cell energy & digestive system - · pdf filelabel the following on the diagram below ......

IB Biology Review Barnes

Cell Energy & Digestive System Topic 2.5 – Enzymes Enzymes control the metabolism of the cell. Be able to:

Describe how enzymes have an active site to which specific substrates bond.

Outline the process by which enzyme catalysis involves molecular motion and the collision of substrates with the active site.

Explain how temperature, pH and substrate concentration affect the rate of activity of enzymes.

Describe how enzymes can be denatured.

Describe how immobilized enzymes are widely used in industry.

Explain methods of production of lactose-free milk and its advantages.

Design of experiments to test the effect of temperature, pH and substrate concentration on the activity of enzymes.

Conduct an experimental investigation of a factor affecting enzyme activity. Label the following on the diagram below: Enzyme, Substrate, Products, Active Site

Is the above reaction anabolic or catabolic? How do you know? On the graph, explain why the reaction rate is high in the beginning, then levels off


Why does the reaction rate increase until the optimum temperature? What does “optimum” mean? Why does the rate decline rapidly after the optimum? Why are there two different optimal pH values on the graph? What happens to an enzyme that is out of its pH range? Pepsin is produced in the stomach, then would move to the small intestine, which is where trypsin is found. What happens to pepsin once it is in the small intestine? Why? The beads to the right can contain the enzyme lactase, which breaks down lactose. What would be the benefits of treating milk in this way to make it lactose-free? Topic 2.8 – Cell Respiration Cell respiration supplies energy for the functions of life. Be able to:

Outline how cell respiration is the controlled release of energy from organic compounds to produce ATP.

Describe how ATP from cell respiration is immediately available as a source of energy in the cell.

Describe how anaerobic cell respiration gives small yield of ATP from glucose.

Describe how aerobic cell respiration requires oxygen and gives a large yield of ATP from glucose.

Explain how the use of anaerobic cell respiration in yeasts produces ethanol and carbon dioxide in baking.

Explain lactate production in humans when anaerobic respiration is used to maximize the power of muscle contractions.

Analyze the results from experiments involving measurement of respiration rates in germinating seeds or invertebrates using a respirometer.


Are these reactions catabolic or anabolic? How do you know? Are these hydrolysis or condensation reactions?

Outline the relationship between exercise intensity and lactate levels in the blood.

Aerobic Respiration Anaerobic Respiration


Topic 2.9 – Photosynthesis Photosynthesis uses the energy in sunlight to produce the chemical energy needed for life. Be able to:

Explain how photosynthesis is the production of carbon compounds in cells using light energy.

Outline how visible light has a range of wavelengths with violet the shortest wavelength and red the longest.

Describe how chlorophyll absorbs red and blue light most effectively and reflects green light more than other colors.

Describe how oxygen is produced in photosynthesis from the photolysis of water.

Explain why energy is needed to produce carbohydrates and other carbon compounds from carbon dioxide.

Explain how temperature, light intensity and carbon dioxide concentration are possible limiting factors on the rate of photosynthesis.

Outline changes to the Earth’s atmosphere, oceans and rock deposition due to photosynthesis.

Draw an absorption spectrum for chlorophyll and an action spectrum for photosynthesis.

Design an experiment to investigate the effect of limiting factors on photosynthesis.

Analyze the separation of photosynthetic pigments by a chromatograph.

Label from red to violet.


Absorption Spectrum is the range of wavelengths that are absorbed by chlorophyll Action Spectrum is the range of wavelengths of light that can be used in the light-dependent reactions. There are different due to multiple pigments that can absorb light, so those combined together make up the Action spectrum. The Absorption Spectrum shown is JUST one chlorophyll Is photosynthesis anabolic or catabolic? Is this hydrolysis or condensation? Is energy required or released? Where is the energy coming from? (two sources) What effect does increased CO2 have on photosynthesis? Why? What impact does increase in temperature have on photosynthesis? Why? Although not shown on the graph, what impact would increased light intensity have on photosynthesis and why? There is something called a Rf value with this – it’s just the distance traveled by the pigment divided by the solvent front (which is the maximum distance the solvent traveled). It’s expressed as a decimal. The pigments travel differently due to size and how well they dissolve in the solvent. The solvent is organic – a mixture of petroleum ether/acetone. You place the pigment at the bottom of the paper – usually by pressing it into the paper from a leaf using an edge (like a coin). The darker the line, the more pigment is present and usually good separation occurs.


Topic 6.1 – Digestion and absorption The structure of the wall of the small intestine allows it to move, digest and absorb food. Be able to:

Describe how the contraction of circular and longitudinal muscles of the small intestine mixes the food with enzymes and moves it along the gut.

Outline how the pancreas secretes enzymes into the lumen of the small intestine.

Describe how enzymes digest most macromolecules in food into monomers in the small intestine.

Explain how villi increase the surface area of epithelium over which absorption is carried out.

Describe how villi absorb monomers formed by digestion as well as mineral ions and vitamins.

Explain the different methods of membrane transport required to absorb different nutrients.

Explain how processes occurring in the small intestine that result in the digestion of starch and transport of the products of digestion to the liver.

Use dialysis tubing to model absorption of digested food in the intestine.

Draw an annotated diagram of the digestive system.

Identify tissues layers in transverse sections of the small intestine viewed with a microscope or micrograph. Major enzymes of the digestive system:

Organ Enzyme Secreted What it Breaks Down Where the Enzyme Functions

Mouth

Stomach

Pancreas

Gall Bladder


You should be able to label: Longitudinal muscle Circular muscle Epithelium Villi Lumen Sample Paper 1 Questions 1. During aerobic respiration, oxygen gas is consumed at the same rate as carbon dioxide gas is produced. In order to provide accurate volumetric measurements of oxygen gas consumption, the experimental setup should include which of the following? A. A substance that removes carbon dioxide gas B. A plant to produce oxygen C. A glucose reserve D. A valve to release excess water

2. In cells, anaerobic respiration occurs in the A. cell cytoplasm. B. cytochrome system. C. matrix of the mitochondria. D. cristae of mitochondria.

3. Which structure, represented in the diagram shown, absorbs most of the fatty acids and glycerol from the small intestine?

A. Structure A B. Structure B C. Structure C D. Structure D


4. Use the diagram below for the question that follows

Which gas is forming in the test tube shown above? A. carbon dioxide B. hydrogen C. oxygen D. nitrogen 5. The light energy for photosynthesis is captured by A. water. B. hydrogen. C. chlorophyll. D. oxygen. 6. Which of the following diagrams accurately represents the use of gases in both cellular respiration and photosynthesis?

A.

B.

C.

D.

7. Using the diagram below, identify the part of the digestive system that contains structural adaptations called villi.

A. Structure F

B. Structure E C. Structure C D. Structure H

8. Into which parts of the human digestive system are digestive enzymes secreted? A. mouth, esophagus, stomach B. stomach, small intestine, large intestine C. mouth, stomach, small intestine D. esophagus, stomach, large intestine 9. The graph below shows the rate of activity for the enzyme catalase at different temperatures. Catalase helps convert hydrogen peroxide to oxygen gas and water. The rate of catalase activity is directly related to the percent increase in oxygen.

Based on the graph, which of the following conclusions can be made about the functioning of catalase?

A. Catalase is denatured at 34⁰C. B. Catalase cannot function at 51⁰C. C. Catalase functions most efficiently at 51⁰C. D. Catalase works best at 34⁰C.


10. The diagram shows an enzyme catalyzed reaction.

What is represented by Structure X?

A. Substrate B. Product C. Enzyme D. Enzyme-substrate complex

11. The distortion (change in shape) of enzyme molecules that occurs at high temperatures is known as A. synthesis. B. specificity. C. replication. D. denaturation. 12. The graph below shows the effect of substrate concentration on enzyme activity.

Assuming the amount of enzyme has been kept constant, what conclusion can be drawn from section X of the graph?

A. The enzyme has started to denature and the reaction slows down.

B. The reaction has finished and the substrate has been used up.

C. The enzyme is saturated and is working at its maximum reaction rate.

D. Some of the enzyme has been consumed and the reaction has reached a plateau.

13. Enzyme activity was measured for two enzymes at different pH values, shown in the graph below.

At which pH is one enzyme optimal and the other enzyme denatured?

A. pH 5 B. pH 6 C. pH 8 D. pH 10

14. The digestion of starch begins in the A. mouth B. stomach C. gallbladder D. small intestine 15. Which sequence shows the pathway that food takes in the digestive system? A. stomach, esophagus, large intestine, small intestine B. esophagus, stomach, large intestine, small intestine C. stomach, esophagus, small intestine, large intestine D. esophagus, stomach, small intestine, large intestine


Sample Free Response Questions Matter continuously cycles through an ecosystem. A simplified carbon cycle is depicted below.

(a) Identify the key metabolic process for step I and the key metabolic process for step II. [2] (b) Identify an organism that carries out both processes. [1] (c) Explain how carbon is moved through this cycle. [4]

The effects of pH and temperature were studied for an enzyme-catalyzed reaction. The following results were obtained.

(a) Explain how temperature and pH affect the activity of this enzyme. [4] (b) Describe how the structure and function of the enzyme changes at extreme high temperature. [2] (c) If these were results were taken from an experiment, state one controlled variable that would be found in the

pH experiment. [1]


(a) Identify two variables, not already mentioned, that would have to be controlled to ensure that the experimental procedure was valid. [2]

(b) A control tube would be required for each wavelength of light being investigated. Describe the contents of a suitable control tube. [1]

(c) Draw a line graph to show the colorimeter readings against wavelength of light. [4] (d) Explain why the graph of the colorimeter reading against wavelength of light would be considered the action

spectrum. [1]


An investigation was carried out to compare the rate of metabolism in a species of cricket, Gryllus assimilis, at different temperatures. Five crickets were placed in a sealed flask which was fitted with a carbon dioxide sensor as shown in the diagram below.

The flask was placed in a water bath at 5C and left for 10 minutes. The CO2 produced per minute was then measured. This procedure was repeated at 10, 15, 20 and 30C. The results are shown in the table below.

(a) Explain why the flask was left for 10 minutes at each temperature before each reading was taken. [1] (b) A control flask should be included in this investigation. Describe the control and explain its purpose in the

investigation. [2] (c) Draw a line graph to show the results of the investigation. [4] (d) Determine a conclusion from these results as it relates to aerobic respiration. [2]

cell energy & digestive system - · pdf filelabel the following on the diagram below ......

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