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1.2: Osmosis Teacher's Preparation Notes - Biology

1.2: Osmosis Teacher's Preparation Notes - Biology


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This activity provides a sequence of learning activities designed to optimize student learning and understanding of osmosis by beginning with a student investigation of osmosis at the macroscopic level and then moving to analyzing osmosis at the molecular and cellular levels. In Part I, "What is happening to these eggs?" students observe and analyze the effects of osmosis on eggs. In Part II, "Osmosis – Effects on Animal and Plant Cells", analysis and discussion questions introduce students to a molecular and cellular understanding of osmosis and challenge students to apply their understanding of osmosis to several real-world phenomena.

Learning Goals

In accord with the Next Generation Science Standards:

  • This activity helps students to prepare for the Performance Expectation:
    • MS-LS1-2. "Develop and use a model to describe the function of a cell as a whole and ways parts of cells contribute to the function."
  • Students learn one aspect of the Disciplinary Core Idea (LS1.A) "… the cell membrane forms the boundary that controls what enters and leaves the cell."
  • Students engage in recommended Scientific Practices, including "… carrying out investigations", "interpreting data", and "constructing explanations and designing solutions".
  • Discussion of this activity can incorporate two Crosscutting Concepts: "Cause and effect: Mechanism and explanation" and "Structure and function".

Specific Learning Goals include:

  • A selectively permeable membrane allows some types of molecules or ions to pass through, but not others.
  • In biological organisms, each cell is surrounded by a selectively permeable cell membrane which regulates what gets into and out of the cell. Water is a small molecule that readily crosses the selectively permeable cell membrane.
  • Movement of water across a selectively permeable membrane is called osmosis; osmosis results in the net movement of water from a solution with a lower concentration of solutes to a solution with a higher concentration of solutes.
  • If the solution surrounding a cell has a greater concentration of solutes than the cytosol inside the cell, there will be a net movement of water out of the cell. Conversely, if the solution surrounding a cell has a lower concentration of solutes than the cytosol inside the cell, there will be a net movement of water into the cell. This can cause animal cells to burst. However, in plant cells, the influx of water is limited by pressure from the surrounding cell wall.

Supplies

  • For each student group (or just one set of supplies to prepare a demonstration):
    • 2 eggs (To minimize the chance of salmonella infection you may want to use pasteurized eggs, in which case gloves would probably not be necessary.)
    • 2 containers with covers (or plastic wrap)
    • White vinegar (enough to cover each egg in its container)
    • Corn syrup (enough to cover one egg in its container)
    • Water (enough to cover one egg in its container, plus water to wash the corn syrup off of the egg on day 3)
    • At least 3 gloves (An alternative that may be acceptable would be to have students wash their hands thoroughly each time after they have handled an egg.)
    • Paper towels
  • You will also need student access to a sink and either a scale with the container for weighing eggs and/or a measuring tape. Obviously, the activity will proceed more rapidly if you have more than one sink, scale and/or measuring tape.

Instructional Suggestions and Background Information

Part I will require approximately 15 minutes on three consecutive class days. If you can't do Part I as a student investigation, you can present it as a demonstration, which will require less time.

A key is available upon request to Ingrid Waldron ([email protected]). The following paragraphs provide additional instructional suggestions and background information – some for inclusion in your class discussions and some to provide you with the relevant background that may be useful for your understanding and/or for responding to student questions.

I. What is Happening to These Eggs?

An unfertilized egg is a single cell, but a very atypical cell in size and makeup. Most of the egg yolk and white consist of storage molecules (mainly fat in the yolk and mainly protein in the white). In a fertilized, incubated egg these storage molecules are used during the development of the chick. The egg’s DNA is contained in a small spot on the surface of the yolk. The shell membranes that surround the egg cell membrane and lie just under the shell have protein fibers that give the shell membranes much greater strength than a cell membrane. The large size and strong shell membranes of a chicken egg make it useful for demonstrating osmosis, a process which also takes place in more typical cells, but is not as easy to observe.

Overall, a chicken egg is 74% water, which is similar to typical animal cells with ~70% water. White vinegar is about 95% water and 5% acetic acid. Corn syrup is about 20% water, and the rest is monosaccharides, disaccharides and oligosaccharides. A chicken egg has 88% water in the white and 48% water in the yolk. The higher concentration of water in the white is the major reason why, in an egg that has been in corn syrup, the white is much more reduced and the yolk becomes more prominent.

On Day 1, students can see bubbles forming as the acetic acid of the vinegar reacts with the calcium carbonate of the shell to produce CO2 bubbles:

2 CH3COOH + CaCO3 – > Ca(CH3COO)2 + H2CO3 – > Ca(CH3COO)2 + H2O + CO2

On Day 2, there will still be patches of shell on the surface of the eggs. It is possible to remove most of these patches of shell by washing while rubbing gently. However, this step is not necessary and there is a significant risk that students may break the shell membrane. The membranes surrounding the egg are relatively tough, but you do need to be gentle!

On Day 3, students will be able to see a dramatic difference in appearance between the enlarged egg that has been in the water and the shrunken, shriveled egg that has been in corn syrup. The water that diffuses out of the egg in corn syrup typically forms a layer of water on top of the corn syrup; this layer of water will be particularly obvious if you use dark corn syrup, but it is easier to see the shrunken egg if you use clear corn syrup.

You may want to relate the appearance of the egg in corn syrup to the use of salt to kill slugs by causing osmotic loss of water. It should be mentioned that salt in the soil is not good for plant health, so other approaches to getting rid of garden slugs are generally preferable. You may also want to mention the use of salt to preserve foods by making an environment that is too hypertonic for bacteria to survive.

If you modify this activity so your students are not making their own quantitative measurements, you may want to have the following sample data.

Day

Egg 1

Egg 2

Weight (grams)

Circumference (cm)

Weight (grams)

Circumference

1

56.3 (with shell)

~14.0

52.6 (with shell)

~13.9 cm

Egg put into vinegar

Egg put into vinegar

2

72.7 (without shell)

~15.1

65.2 (without shell)

~15.0

Egg put into water

Egg put into corn syrup

3

83.5

~16.0

36.2

~9.9

II. Osmosis – Effects on Animal and Plant Cells

This section engages students in understanding the effects of osmosis on animal and plant cells. In addition, students use their understanding of osmosis to explain several real-world phenomena. You can use this section without the first section, but you would want to omit question 12 in the Student Handout since this question engages students in applying their understanding of osmosis to the results of the egg experiment.

The Student Handout does not introduce the terms hypertonic, hypotonic and isotonic (or hyperosmotic, hypo-osmotic and iso-osmotic), but you can add these terms if they are part of your learning goals for your students.

The molecular mechanism of osmosis is still controversial. The mechanism presented in most college biology textbooks is described below since it provides one way of understanding the phenomenon of osmosis. However, it should be noted that current evidence indicates that this is not the predominant mechanism responsible for osmosis.

Na+, Cl-, and the water molecules that are bound to these ions cannot cross the selectively permeable membrane. Only free water molecules (water molecules that are not bound to ions or other dissolved substances) can cross the selectively permeable membrane.

During osmosis, diffusion results in movement of free water molecules in both directions across the selectively permeable membrane, but more free water molecules move from the region of higher concentration of free water molecules to the region of lower concentration.

The concentration of free water molecules is lower in water with dissolved salt because some of the polar water molecules are attracted to the charged ions, so these water molecules are no longer free but are instead bound to water. Osmosis results in the net movement of water from the region of higher concentration of free water molecules (pure water) to the region of lower concentration of free water molecules (water with dissolved salt).

As mentioned above, current evidence indicates that this is not the most important molecular mechanism for osmosis.

For question 13, the contrast between animal and plant cells illustrates how adaptations are interrelated. Since animals cannot make their own food they generally need to move to get food, so rigid cell walls would be a disadvantage. Furthermore, for many animals, the function of the circulatory, respiratory and digestive systems depends on contractions of muscle cells, which is another reason why rigid cell walls would be a disadvantage.


Sadie cells generally require isotonic surrounding extracellular fluid, whereas plant cells can flourish in hypotonic surrounding fluid. When there is little water in the soil, plant roots are unable to take up water, so the extracellular fluid becomes hypertonic and cells lose turgor pressure which is necessary to support the plant's structure. This is why a plant wilts if there is no rain or you forget to water the plant. In a hypotonic surrounding solution, the net flow of water into a plant cell will stop when enough water has entered the cell so the turgor pressure (b) and the countervailing cell wall pressure (c) match the solute potential (due to the greater solute concentration inside the cell). (For additional explanation, see http://media.collegeboard.com/digitalServices/pdf/ap/bio-manual/Bio_Lab4-DiffusionandOsmosis.pdf).

Challenge Questions

When a person rapidly consumes large quantities of water, this can result in hypotonic extracellular fluid, because the influx of water is too rapid to allow the normal osmotic regulation by the kidneys. The consequent osmotic effects can result in swollen cells, with the most harmful effects on the brain cells, which are especially prone to malfunction due to increased mechanical pressure as the swollen brain cells press against the skull. Hyponatremia (low concentration of sodium) and water intoxication can be fatal. This has been observed in some marathon runners who have consumed excessive amounts of fluids; this can result from excessive consumption of either water or sports drinks, both of which are hypotonic relative to our bodies' extracellular fluids and sweat. This example illustrates that dose makes the poison; in other words, at high enough doses even a necessary and relatively innocuous molecule like water can become fatal. This example also illustrates that official advice (e.g. that athletes need to drink more fluids) can result in harmful outcomes if carried to extremes. The former official advice that athletes should drink "ahead of their thirst" is currently disputed as a result of recent evidence that optimum athletic performance and health is generally observed when athletes have free access to water and drink to thirst ("Dehydration and endurance performance in competitive athletes", Nutrition Reviews 70 (suppl. 2): S5132-6; http://serendip.brynmawr.edu/exchange/bioactivities/sportsdrinks).

Athletes who are very active in a hot environment can become dehydrated as a result of copious sweating, although this is less likely if they have the opportunity to drink when they are thirsty. Dehydration can result in a decreased volume of body fluids, including decreased blood volume. As a result, not enough blood returns to the heart and the heart can't pump enough blood to maintain adequate circulation, so blood pressure drops. This can result in decreased athletic performance and increased risk of heat cramps, heat exhaustion, and in extreme cases heat stroke. Thus, it is important to replace lost water and salt.

Someone who is stranded at sea without any water should not drink ocean water. Ocean water is saltier than the most concentrated urine that human kidneys can produce. Therefore, drinking ocean water will cause an increase in the salt concentration of the body's extracellular fluid, and the hypertonic extracellular fluid will result in dehydration of the body's cells.

The challenge question concerning archaea that are adapted to highly saline environments makes the point that different types of cells are adapted to different environments. This question challenges students to be creative in proposing how cells might adapt to highly saline environments. Many archaea that live in highly saline environments synthesize small organic molecules (e.g. sugars), and the high concentrations of these solutes inside the cell help to balance the high concentration of salt in the surrounding environment so the cell does not lose water by osmosis. This illustrates how osmosis depends on the total concentration of solutes, even when the specific solutes differ. Some halophilic archaea (e.g. Haloferax) have a different adaptation to highly saline environments; they pump potassium into the cell in order to maintain osmotic equilibrium; in these archaea, enzymes and structural cell components have special characteristics to allow them to function at high salt concentrations.

Students may propose other possible adaptations for living in extremely salty environments, and it will be enlightening to discuss their proposals. For example, students may propose having a cell membrane that is impermeable to water; this will provide the opportunity to discuss the problems that would result from having such an impermeable cell membrane. Students may also propose that archaea might pump water across the cell membrane into the cell to counteract the osmotic effects of the hypertonic surrounding solution; thus far, biologists have not found any biological molecule that can directly pump water; instead, water is moved across cell membranes by osmotic gradients which cells can set up by pumping ions.


You can run this as a demonstration, or a class practical where pairs of pupil have an egg and each pair place their eggs in different solutions (amalgamating results to provide whole-class data). If you can manage the number of eggs, each group could have three eggs.

Apparatus and Chemicals

For each group of students:

150 cm 3 of each salt solution to be used.

For the class – set up by technician/ teacher:

De-shelled eggs (Note 1)

Sodium chloride solutions in a range of concentrations, for example, 0%, 10%, 20%. (150 cm 3 of each concentration for each working group)

Health & Safety and Technical notes

Hydrochloric acid (HCl) is described as IRRITANT at concentrations above 2.0 M, causes burns and is irritating to the respiratory system. Technicians will need to take precautions when preparing the eggs, but the rinsed eggs should be low hazard for students to handle.

Sodium chloride is described as low hazard. See CLEAPSS Hazcard.

Wear eye protection as some of the sodium chloride solutions are strong.

Rinse hands if splashed by solutions.

1 To de-shell chicken’s eggs, leave overnight in a large beaker of acid (1.5 M - 2 M of hydrochloric acid is ideal). This will dissolve the shells. Weigh down the eggs with a second beaker containing water, so they are pushed down into the acid and do not float above the surface. This ensures all the shell is removed and there is not a patch left. Trying to pick off a patch will break the egg! Rinse the eggs before use. A de-shelled egg is strong enough to handle with care. If consecutive lessons are several days apart, store the eggs in solutions in the refrigerator.

Ethical issues

These eggs are sold as foodstuffs and are unlikely to be fertile. There may be ethical issues associated with farming processes, but not specifically with this use of the eggs. Students who are vegetarians or vegans may object to handling animal material.

Procedure

SAFETY: Make sure the acid is rinsed off the eggs before use.

Preparation

a De-shell the eggs in acid overnight. Rinse before students handle them.

Investigation

b Ensure the egg is dry by gently patting it with a paper towel.

c Place the egg on a balance and record the mass in a suitable table.

d Put the egg in a 200 cm 3 beaker.

e Pour in enough sodium chloride solution to cover the egg. Record the concentration of sodium chloride used.

f Leave the egg until next lesson – at least 24 hours.

g Pour the sodium chloride solution off the egg.

h Dry the egg carefully using a paper towel.

i Place the egg on the balance and record the mass in the table.

j Calculate change in mass and percentage change in mass.

k Compare the results for the different concentrations of sodium chloride.

Teaching notes

The egg is not a single animal cell. However the egg’s membrane is selectively permeable, so it is a good model to show osmotic effects in animal tissue.

Run the practical by following the procedure, or as investigations with the following variations.

  • Use a full range of salt solutions 0%, 5%, 10%, 15%, 20% etc.
  • Time: Put the eggs in either distilled water or 20% salt solution. Remove and weigh at timed intervals, for example, every 10 minutes.
  • Temperature: Put eggs in a fixed solution at different temperatures, such as 0°C, 5°C, 10°C, 15°C, 20°C, 25°C, and weigh after a fixed time, for example, 30 minutes.

Health and safety checked, September 2008

Downloads

Download the student sheet Investigating osmosis in chickens' eggs (54 KB) with questions and answers.

Related experiments

© 2019, Royal Society of Biology, 1 Naoroji Street, London WC1X 0GB Registered Charity No. 277981, Incorporated by Royal Charter


Osmosis: Demonstration and Types (With Diagram) | Botany

In all biological systems, the solvents is water. Semipermeable membranes permit the movement of solvent molecules but prevent the movement of solute molecules.

Osmosis is a special form of diffusion in which water molecules diffuse in the presence of semipermeable membrane from hypotonic solution to hypertonic solution.

All diffusing molecules are known to possess some kinetic energy, called free energy. Free energy of pure water is higher than that of the same in a solution. The addition of solutes to the water (or solvent) lowers the free energy of the latter and thereby brings a fall in its diffusion pressure.

The lowering of free energy in the solution is due to the attraction and collision between solvent (water) and solute molecules. Thus, higher the concentration of a solution, lower is its free energy or diffusion pressure.

Demonstration of Osmosis:

The basic principles of osmosis can be illustrated most clearly by a simple physical experiment (Fig. 1.2).

A semipermeable membrane, such as parchment paper, is tied over the base of a thistle funnel. The base of the thistle funnel is then filled with a sugar solution and the apparatus placed in a jar of water. The membrane is only slightly permeable to the molecules of sugar but is readily permeable to water. Because of the presence of the sugar molecules the concentration of water within the funnel is lower than the concentration outside in the jar of water.

Water molecules pass through the membrane. The net movement of water will be into the sugar solution. Because of this inward movement, the volume of water inside increases, and hence the solution rises in the stem of the funnel.

The liquid will continue to rise until the height of the water column is such that the pressure exerted downward (i.e., hydrostatic pressure) prevents further inward diffusion. Such a hydrostatic pressure is termed osmotic pressure.

Endosmosis and Exosmosis:

‘Osmosis in which the direction of osmotic flow of water is into the cell”.

Changes in the Cell Due To Endosmosis:

(i) Increase in the volume of the cell sap causing an increase in the internal pressure, (i.e. Turgor pressure).

(ii) Dilution of the cell sap due to the absorption of water.

(iii) Enlargement of the protoplast due to endosmosis. The enlarged protoplast is pressed against the cell wall due to the Internal pressure.

(iv) Cell wall is rigid. It resists increases in the volume and exerts a counter pressure on the enlarging protoplast. (Wall Pressure).

“When the osmotic flow of water is from the inside of the cell to the outer hypertonic medium through the cell membrane.”

Changes in the Cell Due to Exosmosis:

(1) Loss of turgor and decrease in turgor pressure of the cell.

(2) Shrinking of the cell protoplast (plasmolysis).

(3) Cell wall become relaxed.

(4) Decrease in W.P. corresponding to the decrease in T.R

(5) Concentration of the cell sap increases due to the loss of water.

Osmotic Pressure:

Osmotic pressure is also defined as ‘The hydrostatic pressure developed in a solution due to the osmotic flow of solvent (such as water) when the solution is separated from pure solvent by a semipermeable membrane. Osmotic pressure term was coined by Pfeffer. Osmotic pressure is measured in atmosphere, bars or Pascal’s. Instrument used for measuring O.P. is called Osmometer.

Now a days, the term osmotic potential (i.e. solute potential = Ψs) is preferred over osmotic pressure. Numerically, osmotic potential is equal to osmotic pressure but opposite in sign. Osmotic pressure has a positive value while osmotic potential (Ψs) has equal but negative value.

Osmotic pressure can be calculated by the following relationship:

C = Molar concentration of solution.

R = Gas constant which is 0.082

T = Absolute temperature 273°C

Normal Range of Osmotic Pressure Values in Different Plant Groups

Osmotic Concentration (Types of solutions):

1. Hypertonic solution (Hyper = More than):

A solution whose osmotic concentration (solute potential) is more than that of another solutions or cell sap (tonoplasm) is called hypertonic solution. If a cell is placed in hypertonic solution water comes out of the cell by the process of exosmosis and cell becomes flaccid.

2. Hypotonic solution (Hypo = Less than):

A solution whose osmotic concentration (solute potential) is less than that of another solution or cell sap (tonoplasm) is called hypotonic solution. If a cell is placed in hypotonic solution, water enters into the cell by the process of endosmosis and cell becomes of turgid.

3. Isotonic solution (Iso = Same):

A solution whose osmotic concentration (solute potential) is equal to that of another solution or cell sap (tonoplasm) is called isotonic solution. If a cell is placed in a isotonic solution, there will be no change in the cell and the solution.


Unit 3B Transport (2018-2019)

2. Start working on Plasma Membrane Questions (worksheet) using pages 77-78 in the textbook.

Homework - The Plasma Membrane Questions due Friday

Thursday, Nov 8

1. Structure of the Plasma Membrane Notes

2. Work on The Plasma Membrane Questions

Homework - The Plasma Membrane Questions due tomorrow

Friday, Nov 9

3. Work on The Plasma Membrane Internet activity

Homework - Plasma Membrane Internet Activity due Wednesday

Monday, Nov. 12

2. Diffusion through a membrane lab - Pre-Lab and set-up

Homework - Define terms on page 97 (due Wednesday)

Tuesday, Nov. 13

2. Finish Diffusion through a membrane lab

Homework - Define terms on page 97 tomorrow

Wednesday, Nov. 14

Thursday, Nov 15

2. Osmosis in Plant Cells Lab

Per 7 & 9 - No Class (Early Dismissal)

Friday, Nov 16

Osmosis in Plant Cells Lab

Monday, Nov 19 (PM) and Tuesday, Nov. 20 (AM) - (1/2 days for conferences)

1. Finish Cells & Osmosis Notes

2. Facilitated Diffusion Notes

2. Diffusion & Osmosis Activity

Wednesday, Nov. 21-23 - No School (Thanksgiving)

Monday, Nov. 26

2. Facilitated Diffusion & Active Transport Notes

Homework: Section 5-1 & 5-2 Reviews due Wednesday

Tuesday, Nov. 27

3. Review (online) - Passive & Active Transport animation review questions (Google form on Google Classroom)

Homework - Section 5-1 and 5-2 Review due tomorrow Per 3 & 7 - Passive & Active Transport animation review questions (Google form on Google Classroom)

Wednesday, Nov. 28

Online Review Quizzes - watch the animation and take the quiz located below. Record your answers on the worksheet you got in class.

Homework - finish transport animation with Google Forms, online quizzes AND Section 5-2 Review

Thursday, Nov. 29 - Test on the plasma membrane, transport & homeostasis


Trouble Shooting and Cleanup

Tip: "While running the osmosis/diffusion lab today, my students made an interesting discovery. The iodine solution reacted with the glucose test strips (Carolina Biological osmosis lab replacement kit) and turned a color indicating a positive glucose reaction. The students wanted to know how could they determine if glucose diffused out of the dialysis bag since the iodine in the beaker solution already gave them a positive test. Likewise, at the end of the experiment when the iodine had diffused into the dialysis bag, they wanted to know how they could detect that glucose had left (as indicated by a lessened color reaction with the glucose test strips). We ended up running a dialysis bag without iodine so we could detect the glucose by itself, but if you follow the lab as written, you might need to consider this problem."
Jeff Smith, Indiana Academy, Muncie, Indiana. 10/5/99


1.2: Osmosis Teacher's Preparation Notes - Biology

Tuesday
Biology Keystone Exam (No 3rd or 4th)

Lab: Quizlet Module 2 Review

Big Idea: Interdependence in Nature
Ecosystems and Communities
4.1 Climate
-Differentiate between weather and climate.
-Identify the factors that influence climate.
4.2 Niches and Community Interactions
-Define Niche
-Describe the role competition plays in shaping communities.
-Describe the role predation and herbivory play in shaping communties.
-Identify the three types of symbiotic relationships in nature.
4.3 Succession
-Describe how ecosystems recover from a disturbance
-Compare succession after a natural disturbance with succession after a human -caused disturbance.
4.4 Biome
-Describe and compare the characteristics of the major land biomes.
-Identify the areas that are not classified into a major biome.
4.5 Aquatic Ecosystem
-Identify the major categories of freshwater ecosystems.

Continue Keystone Review Packet

H.W. Have Ch. 5 and 6 Note Shell Complete for tomorrow

Finish Ch. 4, Chapter 5 & 6 Note Shell

Big Idea: Matter and Energy, Interdependence in Nature
The Biosphere
3.1 What is Ecology
-Describe the study of ecology?
-Explain how biotic and abiotic factors influence an ecosystem?
-Describe the methods used to study ecology.
3.2 Energy, Producers, and Consumers
-Define primary producers
-Describe how consumers obtain energy and nutrients
3.3 Energy Flow in Ecosystems
-Trace the flow of energy through living systems.
-Identify the three types of ecological pyramids
3.4 Cycles of Matter
-Describe how matter cycles among the living and nonliving parts of an ecosystem.
-Describe how water cycles through the biosphere.
-Explain why nutrients are important in living systems.
-Describe how the availability of nutrients affects the productivity of ecosystems.

Evolution Study Island due Tuesday

Biome Chart and Ch. 6 Packet Due Wednesday

Evolution Study Island Due

Biome Chart and Ch. 6 Packet Due - due tomorrow

Work on Chapter Review Questions - due tomorrow

Correct Review Questions and Review for test

Complete Ch. 4 Note Shell for Homework for Monday

Big Idea: Matter and Energy, Interdependence in Nature

-Describe the study of ecology?

-Explain how biotic and abiotic factors influence an ecosystem?

-Describe the methods used to study ecology.

3.2 Energy, Producers, and Consumers

-Describe how consumers obtain energy and nutrients

3.3 Energy Flow in Ecosystems

-Trace the flow of energy through living systems.

-Identify the three types of ecological pyramids

-Describe how matter cycles among the living and nonliving parts of an ecosystem.

-Describe how water cycles through the biosphere.

-Explain why nutrients are important in living systems.

-Describe how the availability of nutrients affects the productivity of ecosystems.

Biome Chart and Ch. 6 Packet Due - due May 1st

Discuss Keystone and Open Ended Questions

Work on Keystone Packet as a class.

Biome Chart and Ch. 6 Packet Due - due May 1st

Food Web - Practice Labeling and construct your own

Begin Working on Keystone Review Packet

Biome Chart and Ch. 6 Packet Due - due May 1st

2nd Bench Mark/ When finished work on Evolution Study Island

Biome Chart and Ch. 6 Packet Due - due May 1st

Big Idea: Evolution of Populations

-Define evolution in genetic terms

-Identify the main sources of genetic variation in a population

-State what determines the number of phenotypes for a trait

17.2 Evolution as Genetic Change in Populations

-Explain how natural selection affects single-gene and polygenic traits.

-Explain how different factors affect genetic equilibrium.

17.3 The Process of Speciation

-Identify the types of isolation that can lead to the formation of new species.

-Describe the current hypothesis about Galapagos finch speciation.

19.2 Patterns and Processes of Evolution

-Identify the processes that influenced survival or extinction of a species or clade.

-Contrast gradualism and punctuated equilibrium.

-Describe adaptive radiation and convergent evolution.

-Explain the evolutionary characteristics of coevolving organisms.

-Explain the endosymbiotic theory.

Review for Ch. 17 and 19.2 Test

Big Idea: Evolution of Populations

-Define evolution in genetic terms

-Identify the main sources of genetic variation in a population

-State what determines the number of phenotypes for a trait

17.2 Evolution as Genetic Change in Populations

-Explain how natural selection affects single-gene and polygenic traits.

-Explain how different factors affect genetic equilibrium.

17.3 The Process of Speciation

-Identify the types of isolation that can lead to the formation of new species.

-Describe the current hypothesis about Galapagos finch speciation.

19.2 Patterns and Processes of Evolution

-Identify the processes that influenced survival or extinction of a species or clade.

-Contrast gradualism and punctuated equilibrium.

-Describe adaptive radiation and convergent evolution.

-Explain the evolutionary characteristics of coevolving organisms.

-Explain the endosymbiotic theory.

Continue What Darwin Never Knew

Finish Note Packet for Thursday

Quizlet Warmup - Vocab Quiz on Friday

Have Note Packet done for Thursday

Study Island - Evolution - due by Monday

Have Note Packet done for Thursday

Quizlet Warm Up - Vocab Quiz on Monday

Ch. 17 and 19.2 Test Next Tuesday

Quizlet Live Review- Vocab Quiz Monday

Review Questions Pg. 504-505 #1-25, Pg. 566 12-20 - Due Monday

Big Idea - Evolution
16.1 Darwin's Voyage of Discovery
- Discuss Darwin's contribution to science
-Describe the three patterns of biodiversity noted by Darwin
16.2 Ideas the Shaped Darwin's Thinking
- Identify the conclusions drawn by Hutton and Lyell about Earth's History
-Describe Lamarck's hypothesis of evolution
-Describe Malthus's view of population growth
-Explain the role of inherited variations in artificial selection

16.3 Darwin Presents His Presents

-Describe the conditions under which natural selection occurs

-Explain the principle of common descent

16.4 Evidence of Evolution

-Explain how geologic distribution of species relates to their evolutionary theory

-Explain how fossils and the fossil record document the descent of modern species from ancient ancestors.

-Explain how molecular evidence can be used to trace the process of evolution.

Finish What Darwin Never Knew

Chapter Review Questions pg. 476-477 #1-29 - due Wednesday

Chapter Review Questions pg. 476-477 - due Thursday

Work on Ch. Review Questions

Read Section 17.1 and 17.2 and complete 17.1 and 17.2 in packet (Due Monday)

Big Idea - Evolution
16.1 Darwin's Voyage of Discovery
- Discuss Darwin's contribution to science
-Describe the three patterns of biodiversity noted by Darwin
16.2 Ideas the Shaped Darwin's Thinking
- Identify the conclusions drawn by Hutton and Lyell about Earth's History
-Describe Lamarck's hypothesis of evolution
-Describe Malthus's view of population growth
-Explain the role of inherited variations in artificial selection

16.3 Darwin Presents His Presents

-Describe the conditions under which natural selection occurs

-Explain the principle of common descent

16.4 Evidence of Evolution

-Explain how geologic distribution of species relates to their evolutionary theory

-Explain how fossils and the fossil record document the descent of modern species from ancient ancestors.

-Explain how molecular evidence can be used to trace the process of evolution.

Read 16.1 and 16.2 (Pgs. 450 - 458), complete section review questions. Pg. 453 # 1,2

Begin Chapter 16 Powerpoint and Notes

Correct Section Review Questions
Work on 16.1 and 16.2 Packet

Complete Chart of People who Influenced Darwin

Correct 16.1 and 16.2 Packet

Begin Notes on 16.3 and 16.4

Read Pgs. 460-473 and complete 16.3 and 16.4 Packet

Lab Pd. 1 - What Darwin Never Knew

Current Articles on Evolution

-Explain the relationship between genes and the environment.

Watch dihybrid video and complete worksheet

-Explain the relationship between genes and the environment.

Begin Monohybrid Problems

Monohybrid Practice Worksheet

Monohybrid Quiz on Wednesday

Correct Monohybrid Worksheet

Complete Practice Problems

Monohybrid Quiz on Thursday

Introduce Dihybrids - Wolf problem for homework

Correct Monohybrid Problems

Practice More Monohybrid Problems

Finish Coin Toss Baby Lab

-Explain the relationship between genes and the environment.

Genetic Engineering Research

DNA Crime solving video clip

Finished Genetic Engineering Research

-Summarize the process of DNA fingerprinting and explain its uses.

Test on Transcription/Translation

Read Biotechnology Article and Answer Questions - due Wednesday

Collect Biotechnology Article Questions

Genetic Engineering Research Activity

Big Idea: Growth, Development, and Reproduction

Big Ideas: Information and Heredity, Cellular Basis of Life

DNA
1. Contrast RNA and DNA.
2. Explain the process of transcription.

Ribosomes and Protein Synthesis
1. Identify the genetic code and explain how it is read.
2 Summarize the process of translation.
Mutations
1. Define mutations and describe the different types of mutations.
2. Describe the effects mutations can have on genes.

Finish Notes if necessary

13.1 and 13.2 Packets due Tomorrow

Transcription/Translation Quiz on Wednesday

Protein Synthesis Worksheet

Transcription/Translation Quiz tomorrow

DNA Vocab Quiz on Thursday

Review for Ch. 13 Test on Monday

Big Idea: Growth, Development, and Reproduction

Big Ideas: Information and Heredity, Cellular Basis of Life

DNA
1. Contrast RNA and DNA.
2. Explain the process of transcription.

Ribosomes and Protein Synthesis
1. Identify the genetic code and explain how it is read.
2 Summarize the process of translation.
Mutations
1. Define mutations and describe the different types of mutations.
2. Describe the effects mutations can have on genes.

Work on 13.2 Packet - due Wednesday

Video Clip on Translation Process - Human Genome Animation

Finish Notes if necessary

Protein Synthesis Worksheet

Video Clip on Translation Process - Human Genome Animation

Complete 13.1 and 13.2 Packet for Tuesday

1. Identify the chemical components of DNA.

2. Discuss the experiments leading to the identification of DNA as the molecules that carries the genetic code

3. Describe the steps leading to the development of the double-helix model of DNA

1. Summarize the events of DNA replication

2. Compare DNA replication in prokaryotes with that of eukaryotes

Begin Constructing DNA Model

Work on Ch. 13 Intro Questions

Pipe Cleaner Model Activity

Hand out midterm review packet - due next Friday

Meiosis Diagram/checklist Worksheet - finish for homework, due tomorrow

Midterm Review Packet due next Friday

Vocab Warm up - Quiz next Tuesday

Mitosis/Meiosis Test next Wednesday

Correct Homework Wksh, meiosis diagrams/checklist

Midterm Review Packet due next Friday

Correct HW - 10.3 and 10.4 packet

Students will be able to identify the possible benefits and issues relating to stem cell research.

Review Mitosis - Worksheet

Read 10.3 and 10.4. - Complete Worksheets for Monday

Big Idea: Cellular Basis of Life, Energy

Discuss where organisms get energy.
Define Cellular Respiration
Determine the relationship between photosynthesis and cellular respiration
9.2 Objectives
Determine what happens during the process of glycolysis and the krebs cycle
9.3 Objectives
Explain how organisms generate energy when oxygen is not available.

Finish Cell Respiration Notes

Review Cell Respiration - Energy in a cell worksheet

Review Cell Respiration and Photosynthesis - Quiz Wednesday

Photosynthesis/Cell Respiration Quiz

Work on Ch. 10 Intro Questions - Due Friday

Warm up - Get chromebooks and answer question in Google Classroom

Begin Mitosis Notes - Ch 10.1

Chapter 10 Intro Questions due Tomorrow

Continue Ch. 10 Notes - 10.2

Big Idea: Cellular Basis of Life, Energy

Students will be able to explain why ATP is useful to cells.
Students will be able to explain the purpose of photosynthesis.
8.2 Objectives
Students will learn the equation for photosynthesis
Students will be able to describe the role of light, pigments, and electron carrier molecules in photosynthesis.
8.3 Objectives
Students will be able to list the events in the light dependent reactions and in the dark reactions.
Students will be able to compare and contrast the light and dark reactions.

Students will be able to explain how different factors can affect the rate of photosynthesis.

Reinforcement Worksheet on ATP

Check and correct Photosynthesis Graphs

Finish Photosynthesis Notes

Photosynthesis Quiz Tomorrow

Begin Ch. 9 Intro Questions

Big Idea: Cellular Basis of Life, Energy

Students will be able to explain why ATP is useful to cells.
Students will be able to explain the purpose of photosynthesis.
8.2 Objectives
Students will learn the equation for photosynthesis
Students will be able to describe the role of light, pigments, and electron carrier molecules in photosynthesis.
8.3 Objectives
Students will be able to list the events in the light dependent reactions and in the dark reactions.
Students will be able to compare and contrast the light and dark reactions.

Students will be able to explain how different factors can affect the rate of photosynthesis.

Finish Photosynthesis Notes

No Class - Parent Teacher Conferences

No Class - Early Dismissal

Big Idea: Cellular Basis of Life, Energy

Students will be able to explain why ATP is useful to cells.
Students will be able to explain the purpose of photosynthesis.
8.2 Objectives
Students will learn the equation for photosynthesis
Students will be able to describe the role of light, pigments, and electron carrier molecules in photosynthesis.
8.3 Objectives
Students will be able to list the events in the light dependent reactions and in the dark reactions.
Students will be able to compare and contrast the light and dark reactions.

Students will be able to explain how different factors can affect the rate of photosynthesis.

Week 12 11/12 - 11/16
Monday

Review for cell transport quiz tomorrow

Work on Ch. 8 Intro Questions 8.1 and 8.2 - due Friday

Begin Photosynthesis Notes

Chloroplast Graphing Worksheet

Parent Teacher conferences- no class

Early Dismissal - weather related

Finish Photosynthesis Notes

Or possibly Photosynthesis Lab

1. Explain what is happening during diffusion and osmosis.

2. Compare and contrast passive and active transport

1. Explain how individual cells maintain homeostasis.

2. Determine how the cells of multicellular organisms work together to maintain homeostasis.

Correct Osmosis/Diffusion Worksheet

Quizlet Live Vocab Review

Finish Gummy bear osmosis/diffusion lab

Work on 7.3 part of cell packet

1. Examine functions of all cell organelles.

2. To learn how cell structures are adapted to their functions.

4. Compare and contrast chloroplasts and mitochondria.

5. Explain importance and structure of cell membrane.

1. Explain what is happening during diffusion and osmosis.

2. Compare and contrast passive and active transport

Review Prokaryotes and Eukaryotes

Work on 7.1 and 7.2 of Cell Packet - Complete for Tuesday

Review for Cell Organelle Test on Wednesday

Notes on Cell Membrane Structure

2. Describe how the different types of microscopes work.

3. Distinguish between prokaryotes and eukaryotes.

1. Examine functions of all cell organelles.

2. To learn how cell structures are adapted to their functions.

4. Compare and contrast chloroplasts and mitochondria.

5. Explain importance and structure of cell membrane.

Correct Organelle Worksheet

Cell Diagram - Students draw and label from board

Cell Organelle Quiz on Friday

Review Organelles - Quiz tomorrow

Work on 7.3 Questions - due Tuesday

2. Describe how the different types of microscopes work.

3. Distinguish between prokaryotes and eukaryotes.

1. Examine functions of all cell organelles.

2. To learn how cell structures are adapted to their functions.

4. Compare and contrast chloroplasts and mitochondria.

5. Explain importance and structure of cell membrane.

Cell Theory and Eukaryotes/Prokaryotes

Correct Organelle Chart in Class

Finish Correcting Organelle Chart

Warm up - cell drawings worksheet

Finish Coloring Cell Diagram

Big Idea: Matter and Energy

To learn the basic chemical principles that affect living things.

1. Identify the three subatomic particles found in atoms

2. Describe the two main types of chemical bonds

1. Explain the unique properties of water.

2. Explain the difference between acidic and basic solutions.

1. Describe the unique qualities of carbon

2. Describe the structures and functions of each of the four groups of macromolecules.

1. Explain how chemical reactions affect chemical bonds

2. Describe how energy changes affect how easily a chemical reaction will occur.

3. Explain why enzymes are important to living things.

Complete Review Crossword for Thursday

Ch. 2 Chemistry Test on Friday

Look at Pineapple record results and work on questions

Ch. 2 Chemistry Test on Friday

Ch. 2 Chemistry Test tomorrow

Begin working on Ch. 7 Cell Questions

Big Idea: Matter and Energy

To learn the basic chemical principles that affect living things.

1. Identify the three subatomic particles found in atoms

2. Describe the two main types of chemical bonds

1. Explain the unique properties of water.

2. Explain the difference between acidic and basic solutions.

1. Describe the unique qualities of carbon

2. Describe the structures and functions of each of the four groups of macromolecules.

1. Explain how chemical reactions affect chemical bonds

2. Describe how energy changes affect how easily a chemical reaction will occur.

3. Explain why enzymes are important to living things.

Review Macromolecules - make foldable

Review Macromolecules - Sorting Game

Quiz on 2.3, Organic Molecules Thursday

Quiz on 2.3, Organic Molecules Thursday

Work on Review Packet - due Wednesday

Big Idea: Matter and Energy

To learn the basic chemical principles that affect living things.

1. Identify the three subatomic particles found in atoms

2. Describe the two main types of chemical bonds

1. Explain the unique properties of water.

2. Explain the difference between acidic and basic solutions.

1. Describe the unique qualities of carbon

2. Describe the structures and functions of each of the four groups of macromolecules.

1. Explain how chemical reactions affect chemical bonds

2. Describe how energy changes affect how easily a chemical reaction will occur.

3. Explain why enzymes are important to living things.

Finish Water Lab - Questions

Review Properties of water

Begin 2.3 Organic Chemistry Notes

Chemical Models - Build Sucrose

Big Idea: Matter and Energy

To learn the basic chemical principles that affect living things.

1. Identify the three subatomic particles found in atoms

2. Describe the two main types of chemical bonds

1. Explain the unique properties of water.

2. Explain the difference between acidic and basic solutions.

1. Describe the unique qualities of carbon

2. Describe the structures and functions of each of the four groups of macromolecules.

1. Explain how chemical reactions affect chemical bonds

2. Describe how energy changes affect how easily a chemical reaction will occur.

3. Explain why enzymes are important to living things.

Complete Chapter 2 Questions

Chapter 2 Chemistry Notes

Review Inorganic Chemistry

Students will be able to identify the parts of a microscope.

Students will learn the correct procedure to follow when completing microscope drawings.

Students will able to correctly use the microscope to observe microscopic organisms.

Make sure Study Island is done for tomorrow

Review Characteristics of Life Lab

Begin working on Chapter Review Questions - due Wednesday

Correct Review Questions/Review for test

Introduce Microscope - Label parts

Begin working on Ch. 2 questions - due next Monday

-State the goals of science

-Describe the steps used in the scientific method

-Explain the significance of a scientific theory

-Explain the eight characteristics of life

Check 1.2 and 1.3 Questions

Chapter 1 Test next Wednesday

Chapter 1 Test next Wednesday

Characteristics of Life Lab - finish for homework

Vocab Review - Vocab Quiz Tuesday

Use computers to set up study island. Due 9/11

T est on Ch. 1 next Wednesday

-Introduce course material and familiarize students with resources

-State the goals of science

-Describe the steps used in scientific methodology.

-Explain what a scientific theory is.

Assign Chromebooks, log in to Google Classroom

Complete Personal Info Form

Discuss Importance of Course

Homework - Have book covered by Thursday

Review Syllabus - Have parent sign for H.W. for Wed.

Share Previous year student quotes

H.W. - Read and Complete Outline for Section 1.1, pages 3-9, book covered by Thursday.

Turn in Parent Syllabus Sheets

H.W. - Read and complete Section 1.1 questions for tomorrow. Pages 3 -15 , Book covered by Thursday.

Books will be checked for covers, Parent Signature Sheets Collected

H.W. - Read and Outline Section 1.2 and 1.3, pages 10-25

Applied Biology Syllabus

Worm diagrams & Chordate Powerpoint

No Class - Awards Ceremony

Collect Ch. 15 and 16 Packets

Chapter 5
Big Idea: Interdependence in Nature
Populations
5.1 How Populations Grow
-List the Characteristics used to describe a population
-Identify factors that affect population growth
-Describe exponential growth
-Describe logistic growth
5.2 Limits to Growth
-Identify factors that determine carrying capacity.
-Identify the limiting factors that depend on population density.
-Identify the limiting factors that do not depend on population density.
5.3 Human Population Growth
Discuss the trend of human population growth.
Explain why population growth rates differ in countries throughout the world.
Chapter 6
Big Idea: Interdependence in Nature
Humans in the Biosphere
6.1 A Changing Landscape
-Describe human activities that can affect the biosphere
-Describe the relationship between resource use and sustainable developement
6.2 Using Resources Wisely
-Describe how human activities affect soil, land, air, and water resources
6.3 Biodiversity
-Describe biodiversity and explain its value.
-Identify current threats to biodiversity.


1.2: Osmosis Teacher's Preparation Notes - Biology

a. Engage - Discuss with the class the necessity for the cell membrane as a physical barrier protecting the contents of the cell. The selective permeability of the cell should be emphasized.

b. Demo - Students explore the diffusion through a simple demo. Students will write down their observations as the teacher adds a drop of food coloring to a beaker of water. This demo is repeated in cold water and hot water to study the effect of temperature on the process of diffusion. Students are asked to write down and share other examples of diffusion experienced in everyday life.

a. Pre-lab - Students explore the effect of different concentrations of salt solution on Elodea cells under the microscope (Slides are prepared in advance). Students are encouraged to sketch the cells and make observations on their appearance. The post-activity discussion should focus on the student's explanations of the changes they observed.

b. Lab activity - Students work in groups of 2-3 to design and test their own hypothesis regarding the effects of various salt solutions on the mass and appearance of potato slices. Review the Elodea activity if necessary.

Download Osmosis Lab - Powerpoint or PDF

As a post-laboratory exercise, discuss mechanisms by which cells and our body counter the effects of unfavorable osmotic environments.


Photosynthesis

General Process of Photosynthesis

  • Sunlight is absorbed by chlorophyll (found in thylakoidmembranes of the chloroplast).
  • Chlorophyll molecules are arranged into photosystems.
  • This absorbed energy is used to split water into three different components:
    1. Hydrogen ions (also called protons) are stored in the chloroplast – an area called the proton pool.
    2. Oxygen passes out of plant cell and leaf into the atmosphere.
    3. Electrons are given to chlorophyll.
  • Chlorophyll that has energy because of sunlight transfers that energy to its electrons, creating high-energy electrons.
  • These high-energy electrons are combined with protons and carbon dioxide to make glucose.

Detailed Process of Photosynthesis

Photosynthesis occurs in the chloroplast in two stages:

  • Light stage – requires the direct input of light and occurs in the thylakoid membranes.
  • Dark stage (light-independent stage OR Calvin Cycle) – does not require the direct input of light and occurs in the stroma.

Light Stage

  • Sunlight photon strikes a cluster of chlorophyll molecules called a photosystem.
  • The chlorophyll molecules transfer the energy to a reaction center chlorophyll (RCC).
  • The energy is absorbed by an electron which becomes a ‘high-energy electron‘.
  • The energised electron is released from the RCC and can take one of two paths:

1. Cyclic pathway (pathway 1)
2. Non-cyclic pathway (pathway 2)

A photosystem

1. Cyclic pathway
  • The energised electron is picked up by an electron acceptor.
  • It is passed from electron acceptor to electron acceptor losing energy along the way.
  • This energy is used to power the production of ATP from ADP and a phosphate.
  • Once the electron has been passed through it is taken back up by the RCC (chlorophyll).
  • The ATP is passed onto the next stage of photosynthesis – the dark stage.
2. Non-cyclic pathway (pathway 2)
  • The energised electron is picked up by an electron acceptor.
  • It is passed from electron acceptor to electron acceptor losing energy along the way.
  • This energy is used to power the production of ATP from ADP and a phosphate.
  • The photosystem is deficient in electrons and splits water into electrons, protons and oxygen gas (photolysis).
  • The electrons are taken up by the photosystem, the protons are stored in a proton pool within the chloroplast and the oxygen gas is either released into the atmosphere or used in respiration.
  • The electrons that passed through the electron acceptors are now low-energy electrons and are now passed onto another photosystem.
  • Light strikes this second photosystem and the electrons are re-energised.
  • The electrons are released and captured by NADP + to become NADP – .
  • Protons are attracted towards and taken up by NADP – to become NADPH.
  • NADPH and ATP are passed onto the next stage of photosynthesis – the dark stage.

Dark Stage (Calvin cycle)

  • NADPH and ATP from the light stage are used to reduce (addition of protons and electrons) carbondioxide in the stroma of the chloroplast.
  • Glucose isformed in this reaction.
  • As a result, NADPH is converted back to NADP + and ATP is converted back to ADP and a phosphate.

Mandatory Experiment: to investigate the effect of light intensity OR carbon dioxide concentration on the rate of photosynthesis

Equipment:

  • Pondweed (Elodea)
  • Metre stick
  • Pond water
  • Thermometer
  • Paperclip
  • Sodium hydrogen carbonate
  • Stopwatch
  • Backed blade
  • Strong fluorescent light source
  • Beaker and test tube

Method:

  • Obtain fresh pondweed.
  • Cut a small section using the backed blade and crush the cut end slightly between your fingers.
  • Place pondweed in a test tube with pond water.
  • Ensure the cut end is facing upwards and weigh the pondweed down by attaching a paperclip.
  • Shine the strong light source on the pondweed for 5 minutes to allow the pondweed to adjust.
  • Move the light source various distances from the pondweed.
  • Allow the pondweed to adjust to each new light intensity for 5 minutes before counting the number of bubbles per minute.
  • Count the number of bubbles per minute at each distance.
  • Calculate the light intensity at each distance by using the following formula: 1 /d 2 (where d is the distance from the light source)
  • Fill in the table below:
Apparatus setup for examining the effect of light intensity on the rate of photosynthesis

Note: It’s okay to touch the eggs, but remember to wash your hands afterwards to avoid any nasty surprises!

1. Place one egg in each glass. Pour in enough vinegar to cover each egg. Bubbles will start to form around the egg, and it’ll float up. To keep it submerged, put a butter knife in the glass to hold it down.

2. Put the three glasses in the refrigerator and allow to sit for 24 hours.

3. Gently holding the egg in the glass, pour out the old vinegar. Replace with fresh vinegar, and let sit in the refrigerator for another 24 hours. Repeat this process until the shells are fully dissolved and only the membrane remains. This should take about 2-3 days.

4. Gently remove the eggs using the slotted spoon and rinse with tap water in the sink. Rinse out the empty glasses as well.

5. Gently put the shell-less eggs aside for a moment on a plate.

6. Prepare three different sugar-water solutions as follows, labeling with sticky notes:

Glass 1: Label “hypertonic”. Pour in one cup of corn syrup.

Glass 2: Label “isotonic”. Add 1 ½ tablespoons corn syrup to the one cup measuring cup, and fill the remainder with distilled water. Pour into glass (make sure you get all the corn syrup out!) and stir to dissolve.

Glass 3: Label “hypotonic”. Pour in one cup of distilled water.Gently put one shell-less egg in each of the glasses, and let sit in the refrigerator for another 24 hours.

7. Remove the glasses from the refrigerator, and gently put the eggs on a plate. If you weighed the eggs before putting them in each solution, weigh them again. What happened to each of the eggs?


Biology Notes PDF for SSC & Railways Competitive Exams

Download Biology notes PDF useful for class 11th, class 12th, SSC CGL, CHSL Competitive exams, UPSC (Civil services – IAS) and RRB NTPC, ALP & railway Group-D.

IMPORTANT SCIENTISTS RELATED TO BIOLOGY

A Biologist best known for his science of evolutions Charles Darwin
French Biologist known for his discoveries of the Principals of Vaccination and Pasteurization Louis Pasteur
American Molecular Biologist known for his contribution to the discovery of structure of DNA with Francis Crick and Rosalind Franklin in 1953 James Watson
Scottish Physican known for his discovery of enzyme and the world’s first antibiotic substance benzyl penicillin (Penicillin G) Alexander Fleming
German Microbiologist credited as the founder of modern bacteriology Robert Koch
Renowned Swedish Botanist Known for Binomial Nomenclature, Taxonomy Carl Linnaeus
German botanist and co-founder of Cell Theory along with Theodor Schwann and Rudolf Virchow Matthias Jakob Schleiden
Italian biologist and physician, who is referred to as the Father of microscopical anatomy, histology, physiology and embryology Marcello Malpighi
German Jewish physician and scientist who worked in the fields of hematology, immunology, and antimicrobial chemotherapy Paul Ehrlich
Austrian biologist, physician, and immunologist credited with the development of Blood Group System, discovery of Rh Factor and Poliovirus Karl Landsteiner
French physician who won the Nobel Prize in Physiology in 1907 for his discoveries of parasitic protozoans as causative agents of infectious diseases such as malaria and trypanosomiasis Charles Louis Alphonse Laveran
Estonian scientist considered as the founding father of embryology Karl Ernst von Baer
Romanian-American cell biologist. Described as “the most influential cell biologist ever”, in 1974 he was awarded the Nobel Prize in Physiology and Medicine along with Albert Claude and Christian de Duve George Emil Palade
Dutch microbiologist and botanist and often considered one of the founders of virology and environmental microbiology Martinus Beijerinck

IMPORTANT ON-LINERS IN BIOLOGY FOR RRB EXAMS (ALP AND GROUP D), SSC EXAMS, UPSC EXAMS

  • Cell is the basic building block of all living Organisms, it is the smallest unit of Organisation in a living thing.
  • There are two types of Cells: Prokaryotes and Eukaryotes
  • Cell was first discovered and coined by Robert Hooke in 1665
  • Theory of Cell is first credited to Theodor Schwann and Matthias Jacob in 1830s
  • Cell Nucleus was first described by Franz Bauer in 1804 however, the discovery is credited to Scottish Botanist Robert Brown in 1831 for his detailed description of Cell Nucleus

Constituents of a Cell:

  • Cell Organelles: Organelles are observed in Eukaryotic Cells which have definite shape of nucleus, Cell Organelles use membrane to distinguish their functions from the rest of the Organelles Example of Cell Organelles : Mitochondria, Golgi Apparatus, Ribosome etc…
  • Endocytosis: The process of engulfing matter by a living cell to be utilized for the energy-using process. Amoeba uses this process for processing of food
  • Substances like CO2 and Oxygen move through the cell membrane by a process called Diffusion.
  • Osmosis is the process of movement of molecules through a semi-permeable membrane into a region of higher solute concentration in the direction that tends to equalize the solute concentration on both the sides.
  • Water molecules are transported through the cell membrane by this process of Osmosis
  • Osmosis is a case of Diffusion (through a semi-permeable membrane)
  • Protein and Fat help in building the cell membrane which is known as cell biogenesis
  • The Fluid in a cell excluding the Nucleus containing Organ Cells that perform specific functions of the cell is called Cytoplasm
  • The cell organelle which combines simple molecules into complex molecules and packages them into vesicles and sends them out of the cell is called Golgi Apparatus
  • Digestion of any foreign material is done by lysosomes to keep the cell clean, in one way it is the waste disposal system of the cell.
  • The Power House of the cell – Mitochondria, energy required for various cell processes is released by Mitochondria through ATP (Adenosine-tri-Phosphate) molecules
  • ATP (Adenosine-tri-Phosphate) is referred to as the Energy Currency of the cell
  • The Cell Division is initiated by the Centrioles
  • Chromosomes carry all the information that is required by the cell to grow, divide and reproduce
  • The cell organelles which are found only in plants are Plastids
  • Large network of membrane bound tubes similar in structure to Plasma Membrane where Proteins, Fat Molecules are manufactured is called Endoplasmic Reticulum (ER), There are two types of Endoplasmic reticulum
  • The process in which water is purified in the cell by removing the impurities when it flows from a dilute solution (hypotonic) to a concentrated solution(hypertonic) through a semi permeable membrane is called Reverse Osmosis. In this process, little pressure is applied to overcome the Osmotic Process
  • The Non-Living Part Cell Organelles of the Cell are Vacuoles and Granules
  • The Brain of the Cell – Cell Nucleus which control the different processes in the cell

v They are made up of DNA and similar pattern of DNA is called Gene

– These tissues are tightly packed and form a continuous sheet

– The intercellular spaces in these tissue is negligible

– Cells of epithelium play a crucial role in exchange of materials between the body and the external environment

  • Endocrine is a collection of gland which secrete certain chemical messages called hormones
  • Endocrine glands lack ducts and are also called as ductless glands
  • Different endocrine glands present in the human body are

Contain Millions of Islets of Langerhans which contain

a-cells – which secrete Glucagon and

HORMONES
Hormones are classified into three types based on their structure

  • Antagonism is the paired process of contraction and simultaneous expansion of various muscles in the body
  • Immunity is the body’s ability to repel foreign substances and cells
  • Cell Wall is absent in Animals
  • Cells in an animal burst when surrounded by Hypertonic medium
  • Cells in Plant doesn’t burst when surrounded by Hypertonic Medium due to the presence of Cell Wall
  • Lysosomes are also called the Suicidal Bags of a cell
  • Water constitutes the major component of the cell
  • The chemical process that occurs in a living organism to continue life is called Metabolism
  • Carbohydrates are the important biomolecules that are a major part of the living organisms. They are also called as the Hydrates of Carbon and are primarily produced by Plants
  • All proteins are polymers of Amino Acids
  • Proteins synthesized in the body are called non-essential amino acids
  • Proteins obtained through diet are called essential amino acids
  • Proteins soluble in water are called Globular Proteins Ex: Insulin
  • Proteins not soluble in water are called Fibrous Proteins Ex: Keratin
  • Vitamins are organic compound required by the body to perform biological functions for growth and maintenance of the Organism
  • Vitamins are generally classified as :
  • The in-organic nutrients called as Minerals which are equally essential for the human body in small traces are
  • Fat – one of the three main macronutrients is also known as triglycerides which are esters of three fatty acid chains and alcohol glycerol
  • Cholesterol and triglycerides are lipids, which are insoluble in water but soluble in alcohol
  • The Blood Pressure is controlled by Adrenal Gland
  • Any enzyme that converts proteins into peptides is called protease

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Watch the video: N5 Biology - Transport Across Cell Membranes (November 2022).