Cell Biology Sample Test

Read each of the following questions carefully and select the most appropriate answer. Feel free to ask for clarification if the question is unclear (2 points each out of a possible 100 points).

1. Which of the following statements about the evolution of present_day organisms are true?

a. Eukaryotes preceded prokaryotes
b. Ancestral eukaryotic forms were aerobic
c. Eukaryote got mitochondria from a symbiotic aerobic eubacteria
d. Fungi are derived from archaebacteria
e. The common ancestor cell was an archaebacterium.

2. List the following items in order to size from the smallest to the largest.

a. Protein molecule
b. Human fat cell
c. Carbon atom                          ___ ___ ___ ___ ___ ___
d. Ribosome  
e. Yeast cell
f. Mitochondrion

3. Phospholipids can form bilayer membranes in aqueous environments because they are:

a. hydrophobic 
b. lipids
c. amphipathic
d. hydrophilic
e. amphoretic

4. Charge repulsion and resonance stabilization are two phenomena that help make possible:

a. coupled reactions
b. condensation reactions
c. most active transport mechanisms
d. all of the above
e. none of the above, I don't know what you are talking about

5. Which of the following enzymes is a key allosteric control point in the glycolytic pathway?

a. Hexokinase
b. Phosphofructokinase
c. Pyruvate dehydrogenase
d. Isocitrate dehydrogenase
e. Phosphoglucose isomerase

6. In mammals, muscle cells are able to convert pyruvate to lactate. What purpose does this serve for the organism?

a. It is an important way of generating NADH.
b. It is an important way of generating NAD⁺.
c. It allows the organism to grow in aerobic conditions.
d. It allows more energy to be extracted from fermented carbon compounds.
e. It is an important way for the body to generate heat.

7. Acetyl CoA is:

9. Which of the following statements about hydrogen bonds are true?
a. They are weak covalent bonds that are easily disrupted by heat.
b. They are weak bonds formed between hydrocarbons in water.
c. They are weak bonds formed between nonpolar groups.
d. They are weak bonds only formed in the presence of water.
e. They are weak bonds involved in maintaining the 3_D structure of macromolecules.

8. A common means of providing energy to an energetically unfavorable reaction in a cell is by:

a. generation of a higher temperature by the cell
b. transfer of a phosphate group from the substrate to ADP
c. enzyme catalysis of the reaction
d. coupling of ATP hydrolysis to the reaction
e. coupling of the synthesis of ATP to the reaction

9. Match the chemical groups shown in the first list with their names selected from the second list.

List 1 List 2

a._OH                     1. Amino
b._C=O                   2. Aldehyde
c._COOH                 3. Phosphate
d._CH₃                    4. Carboxyl
e._NH₂                    5. Carbonyl (ketone)
                              6. Methyl
                              7. Amido
                              8. Ester
                              9. Hydroxyl

10. Which of the following statements are false?

a. All protein molecules function by binding specifically to other molecules.
b. Many proteins can bind to more than one ligand.
c. Binding between protein and ligand generally involves noncovalent bonds.
d. Proteins are designed to bind their ligands as tightly as possible.
e. Changes in the amino acid sequence of a protein can decrease binding to a ligand, even if the amino acid affected by the change does not lie in the binding site for the ligand.

11. Which of the following processes must be coupled to an energetically favorable reaction (_ G) in order to occur?

a. Conversion of protein into amino acids.
b. Polymerization of amino acids into polypeptides.
c. Conversion of glucose to carbon dioxide and water.
d. Formation of a bilayer from phospholipids in water.
e. The hydrolysis of ATP.

12. What unit of length would you generally use to give the measurements of a typical human cell?

a. Centimeters
b. Nanometers
c. Millimeters
d. Micrometers

13. Match the structure with its appropriate function (1 point each)

_____ Nucleus a. phospholipid synthesis
_____ SER c. transcription
_____ Ribosomes d. packaging and processing
_____ Golgi e. hydrolytic enzymes
_____ Vesicles b. semi_autonomous
_____ Mitochondria g. transport and storage
_____ Lysosomes h. protein synthesis

Briefly describe or define the following terms or concepts (2 points each)

14. K_m

15. Hydrated Sphere

16. Coiled Coil

17. Purine

18. Oxidation

Discussion, answer the questions as completely as possible in the time provided. Feel free to ask for clarification if the question is unclear (15 points each).

19. Compare and contrast the structure and function of a phospholipid and an amino acid.

20. Allosteric enzymes often use the product of a metabolic pathway to control the functioning of the pathway. Give an example of an allosteric enzyme, how it functions and the details of the immediate metabolic pathway it controls.

21. The concept of free energy is useful to study some of the important metabolic pathways in the life of a cell. Discuss the concept of coupled reactions in terms of free energy relationships. Include an example of a coupled reaction.