microtubule / microfilament

microtubule / microfilament

A. Definition/Comparison Questions
Instructions:In your own words, define the pairs of terms given below. Write in complete sentences, stating the differences and relationships between the two terms, and give specific examples where appropriate.
A complete answer usually requires four to eight sentences.
Each question is worth four marks, for a total of 40 marks.
1. bioluminescence / fluorescence
2. endoplasmic reticulum (ER) / Golgi complex

3. microtubule / microfilament
4. enthalpy / free energy
5. active site / allosteric site
6. first law of thermodynamics / second law of thermodynamics
7. antiport / symport
8. exocytosis / pinocytosis
9. NADH / NADPH
10. aerobic respiration / photorespiration
B. Short Answer/Short Essay Questions
Instructions: Answer each of the questions given below in your own words. Write in complete sentences where appropriate. A complete answer usually requires one to two sentences per mark, so a three-mark question would be answered in three to six sentences. This section is worth a total of 40 marks.
(2 marks) 1. What is a circadian rhythm?What are circadian rhythms?
Circadian rhythms are physical, mental and behavioral changes that follow a roughly 24-hour cycle, responding primarily to light and darkness in an organism’s environment. They are found in most living things, including animals, plants and many tiny microbes. The study of circadian rhythms is called chronobiology.

(2 marks) 2. What is a ribozyme?ribozyme is from ribonucleic acid enzyme, which is also called rna enzyme orcatalyticrna. it is an rna molecule that catalyzes a chemical reaction…Ribozymes are made of RNA yet they are able to catalyze reactions like a protein enzyme would. Often the reaction is just splicing themselves.
it is an enzyme found in the intron of the RNA transcript

 

(3 marks) 3. Define adiabatic cooling.An adiabatic process is a process occurring without exchange of heat of a system with its environment. It is the opposite of adiabatic process, in which heat exchange occurs
Adiabatic processes can occur if the container of the system has thermally insulated walls or the process happens in an extremely short time, so that there is no opportunity for significant heat exchange.

(5 marks) 4. Explain what it means when a reaction has a positive ?G.
?G is the change in free energy of a chemical reaction.
Delta is for difference or change and G is for Gibbs free energy.
G is the energy in a system that is available to do work.
It is the free energy of the products minus the free energy of the substrates.
If the substrates have more free energy than the products, delta-G is negative and the reaction is spontaneous, i.e., exergonic.
If the products have more free energy than the substrates, delta-G is positive and the reaction is not spontaneous, i.e., endergonic.
Free energy will vary with temperature, pressure, and pH but since these are usually constant in humans we will ignore them.

(2 marks) 5. What are gated channels?
(4 marks) 6. Explain what exchange diffusion means, and give an example.
(9 marks) 7. Compare mitochondria and chloroplasts. Include both structure and
function in your answer.
(5 marks) 8. The electron transport chain of aerobic respiration leads to oxidative
phosphorylation of ATP. What is an alternative way to synthesize
ATP? Give an example of a specific reaction that uses this alternative
way.
(8 marks) 9. Chemiosmosis is a process that occurs both in aerobic respiration and
photosynthesis. Explain similarities and differences in chemiosmosis
between the two pathways.
C. Multiple Choice Questions
Instructions: Select the single best answer to each of the questions given below. Each question is worth one mark, for a total of 30 marks.
1. Organisms likely use visible light because
a. a large proportion of the electromagnetic radiation on Earth is light.
b. radiation with a higher energy than light might damage biological molecules more easily.
c. radiation with a lower energy content than light might not have enough energy to excite electrons.
d. radiation with longer wavelengths than light are absorbed by water and carbon dioxide.
e. all of the above
2. Which of the following statements is NOT correct?
a. DNA can be damaged by ultraviolet radiation.
b. The pigment melanin protects plants from excessive damage to their photosynthetic apparatus.
c. Shorter wavelengths of radiation are more harmful to organisms than longer wavelengths.
d. Human skin cells can be harmed by ultraviolet radiation.
e. Visible light contains less energy than ultraviolet radiation.
3. Photoheterotrophs
a. use light as an energy source.
b. are found in protists.
c. use carbon dioxide as a carbon source.
d. are found in certain groups of plants.
e. are NOT found in prokaryotes.
4. Chemoautotrophs
a. use organic or inorganic substances as an energy source.
b. are found in protists.
c. use organic substances as a carbon source.
d. are found in certain groups of plants.
e. are not found in prokaryotes.
5. Under what conditions may adaptive radiation occur? Mostly B
a. when islands are colonized
b. after the demise of a successful group of organisms
c. after the emergence of new physiological pathways
d. when organisms move into new adaptive zones
e. all of the above
6. Climbing plants in tropical forests have a competitive advantage over trees because C
a. they grow relatively slowly.
b. they have a high amount of supporting structure.
c. they have a low amount of leaf biomass.
d. they receive a good amount of sunlight
e. they are usually parasites supported by trees.
7. Which of the following groups of organisms are decomposers? B
a. animals
b. fungi
c. plants
d. algae
e. all of the above
8. Which of the following items is NOT associated with monsoons?
a. rain shadow
b. reversal of wind direction
c. adiabatic cooling
d. high precipitation
e. low air pressure
9. Which of the following is NOT true about ocean currents?
a. They move clockwise in the northern hemisphere.
b. They move counter-clockwise in the southern hemisphere.
c. They are partly caused by trade winds and westerlies.
d. They mix water thoroughly, resulting in a uniform water temperature at similar latitudes.
e. They are influenced by the Earth’s rotation.
10. Some sea slugs are able to perform photosynthesis. They do this by
a. producing their own chlorophyll.
b. eating algal cells and moving the cells to the endodermis.
c. having a mutualistic association with algae.
d. having algal chloroplasts in their endodermis.
e. all of the above.
11. The total potential energy in a system is called
a. entropy.
b. free energy.
c. enthalpy.
d. exothermic.
e. endothermic.
12. Under which condition will a reaction be spontaneous?
a. when?G is positive
b. when?H is negative
c. when the product(s) will have more free energy than the reactant(s)
d. when?S is negative
e. none of the above
13. The binding of a substrate to an enzyme causes a change in the enzyme’s shape. This shape change is known as
a. allosteric inhibition.
b. activation.
c. reversible inhibition.
d. induced fit.
e. denaturation.
14. The part of an enzyme that interacts with its substrate(s) is called d
a. an allosteric site.
b. an induced-fit.
c. a reaction site.
d. an active site.
e. a cofactor.
Use the following figure to answer the next question.

15. Which of the following statements is TRUE?
a. The figure represents a spontaneous reaction.
b. The reactants have more free energy than the products.
c. The products have more free energy than the reactants.
d. The figure represents an exergonic reaction.
e. ?G is negative.
16. Which of the following substances is most difficult to move across a membrane?
a. Na+
b. O2
c. H2O
d. glycerol
e. CO2
17. Receptor mediated endocytosis
a. moves liquids out of the cell.
b. moves unspecified substances into the cell by forming a pocket in the plasma membrane.
c. is very specific.
d. involves a proton pump.
18. Which of the following does NOT apply to electrochemical gradients?
a. There is a difference in the concentration of ions between the two sides of the membrane.
b. There is a difference in the electrical charge between the two sides of the membrane.
c. There is a difference in the electrical charge but not in the concentration of ions between the two sides of the membrane.
d. The energy of the gradient can be used for a number of purposes.
e. Nerve impulses are based on electrochemical gradients.
19. Which of the following is NOT true of symport?
a. Two substances move in opposite directions.
b. Two substances move in the same direction.
c. The diffusion of one substance provides the energy for the transport of a second one.
d. Ions are usually involved.
e. Amino acids are one type of substance involved.
20. A cell needs ________ to obtain unsaturated fatty acids from saturated fatty acids.
a. glycoproteins
b. glycerol
c. cholesterol
d. phospholipids
e. desaturases
21. The role of the oxygen molecules required for aerobic respiration is to
a. accept electrons directly from either NADH or FADH2.
b. accept the low energy electrons at the end of the electron transport chain.
c. form ATP.
d. to produce CO2.
e. store high energy electrons to pass to complex I of the electron transport chain.
22. During chemiosmosis, ________ are transferred from NADH and FADH2 to electronacceptor molecules, and the energy released is used to create a(n) ________ gradient across the inner mitochondrial membrane.
a. ATP molecules; ADP molecule
b. water molecules; oxygen
c. protons; electron
d. ADP molecules; ATP molecule
e. electrons; proton
23. Which of the following terms would you associate with lactate fermentation?
a. NADPH
b. glycolysis
c. ethanol
d. citric acid cycle
e. electron transport chain
24. During the citric acid cycle, each acetyl group entering the cycle yields
a. four ATP, two NADH, and one FADH2.
b. one ATP, two NADH, and four FADH2.
c. three ATP, two NADH, and one FADH2.
d. one ATP, three NADH, and one FADH2.
e. one ATP, two NADH, and three FADH2.
25. Which of the following statements concerning decarboxylation reactions is FALSE?
a. They are one type of general reaction that occurs during aerobic respiration.
b. They involve the removal of two protons and two electrons.
c. They occur as part of the citric acid cycle.
d. They produce CO2 that is then exhaled via breathing.
e. They involve the removal of a carboxyl group (-COOH) from a substrate.
26. The genes coding for rubisco are found
a. both in the nuclear DNA and in the chloroplast DNA.
b. both in the nuclear DNA and the mitochondrial DNA.
c. only in the nuclear DNA.
d. only in the chloroplast DNA.
e. only in the mitochondrial DNA.
27. How (exactly) is water split and oxygen released during photosynthesis?
a. An energy-rich photon directly provides the energy to split water.
b. An enzyme in photosystem I uses the energy of a photon to split water.
c. The oxidized form of P680 splits water.
d. A proton pump provides the energy to split water in the thylakoid lumen.
e. ATP originating from the Calvin cycle splits water.
28. Which of the following reactions occur(s) during the Calvin cycle?
a. photolysis of water
b. synthesis of NADPH
c. synthesis of ATP
d. synthesis of sugars
e. all of the above
29. Reaction centre complexes of the light-dependent reactions contain ________ and ________, which receive energy from ________.
a. chlorophyll; antenna complexes; carotenoids
b. accessory pigments; chlorophyll; antenna complexes
c. carotenoids; proteins; chlorophyll
d. proteins; antenna complexes; carotenoids
e. chlorophyll; proteins; antenna complexes
30. In photosynthesis, how many molecules of carbon dioxide, ATP, and NADPH are needed to form two molecules of glucose?
a. 12, 36, and 24
b. 6, 18, and 12
c. 24, 18, and 24
d. 26, 18, and 24
e. 3, 9, and 6
— End of Assignment 1B —

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