Practice test. Gene Probability of Appearing in

Gamete P 1/4 Q 1/4 R 1/4

1. Three genes----P,Q, and R--- are not linked. The probability of each gene appearing in a gamete is shown in the table above. Which of the calculations below represent the probability that all three genes will appear in the same gamete?

a. ¼ X ¼ X ¼b. ¼ + ¼ + ¼ c. ¼ ÷ ¼ X ¼ d. (¼)1/3

2. In deer, fur length is controlled by a single gene with two alleles. When a deer homozygous for long fur is crossed with a deer homozygous for short fur, the offspring all have fur of medium length. If these offspring with medium-length fur mate, what percentage of their offspring will have long fur?

a. 100%b. 75%c. 50%d. 25%

3. Which of the following statements best supports the idea that certain cell organelles are evolutionarily derived from symbiotic prokaryotes living in host cells?

a. The process of cellular respiration in certain prokaryotes is similar to that occurring in mitochondria and chloroplasts.

b. Mitochondria and eukaryotes have similar cell wall structures.c. Like prokaryotes, mitochondria have a double membraned. Mitochondria and chloroplasts have DNA and ribosomes that are

similar to those of prokaryotes.

4. Here is the pH values of several common materials: cola, 2; orange juice, 3; coffee, 5; human blood 7.4. Which of the liquids has the highest molar concentration of OH- ?

a. Colab. Orange juicec. Coffeed. Human blood

5. If each of the water molecules in the diagram had all of its potential hydrogen bonding sites filled, like the water molecule in the center of the diagram, what would be the total number of water molecules represented?

a. 5b. 8c. 17d. 20

6. In E.coli replication the enzyme primase is used to attach a 5 to 10 base ribonucleotide strand complementary to the parental DNA strand. The RNA strand serves as a starting point for the DNA polymerase that replicates DNA. If a mutation occurred in the primase gene, which of the following would you expect?

a. Replication would only occur on the leading strand.b. Replication would only occur on the lagging strand.c. Replication would not occur on either the leading or lagging strand.d. Replication would not be affected because the enzyme primase is

involved with RNA synthesis.

7. Allolactose stimulates E. coli to produce mRNAs that code for the enzyme β-galactosidase, which breaks down lactose into glucose and galactose. Which of the following is the best description of the role of allolactose?

a. It inhibits DNA replication when lactose levels are high.b. It inhibits translation of the mRNAs for β-galactosidase.c. It is an allosteric inhibitor of β-galactosidase,d. It regulates expression of the gene for β-galactosidase.

8. In a certain group of iguanas, the presence of brown skin is the result of a homozygous recessive condition in the biochemical pathway producing skin pigment. If the frequency of the genotype for this condition is 36%, which of the following is closest to the frequency of the heterozygote genotype in this population> (Assume that the population is in Hardy-Weinberg equilibrium.

a. 16%b. 24%c. 48%d. 64%

For questions 9-11 refer to the U-tube below. The initial setup of a U-tube with its two sides separated by a membrane that permits the passage of water and NaCl by not molecules of glucose. The U-tube was filled on one side with a solution of 0.4 M glucose and 0.5 M NaCl, and on the other side 0.8 M glucose and 0.4 M NaCl.

9. When this U-tube was set up, at time=0 in the experiment, which of the

following was true?a. The solution on side A was hypertonic to the solution on side B.b. The solution on side B was hypertonic to the solution on side A.c. The two solutions were isotonic.d. Active transport moved glucose from side A to side B.

10.After the experiment ran for 1 hour, the expected fluid levels in the U-tube would be

a. Higher on side A than side B.b. Higher on side B than side Ac. Evend. Equal, but the solutes would be reversed.

11.At the conclusion of the experiment, the NaCl woulda. Show no movementb. Show some movement from side A to side Bc. Show some movement from side B to side Ad. Make side A hypertonic

12.Cells that produce digestive enzymes must contain a lot of ______, whereas cells that detoxify poisons in the liver would have an abundance of ________.

a. Smooth endoplasmic reticulum, lysosomes.b. Rough endoplasmic reticulum, smooth endoplasmic reticulum.c. Smooth endoplasmic reticulum, rough endoplasmic reticulum.d. Rough endoplasmic reticulum, lysosomes.

13.In chemiosmosis, ATP is produced as hydrogen ions flow through channels in the ATP synthase complex. This movement of hydrogen ions is accomplished by which of the following processes?

a. Active transportb. Facilitated diffusionc. Osmosisd. Cotransport

14.In prokaryotic cell, genes that are involved in the same pathway are clustered in operons under the control of a single promotor. How are the coordinated transcriptions of eukaryotic genes involved in the same pathways regulated?

a. Each gene has its own promotor and the genes are located on the same chromosome

b. The gens are located in the same region of the chromosome, and enzymes methylate the entire region to activate transcription.

c. The genes respond to different transcription factors that all activated simultaneously.

d. The genes may be on different chromosomes, but each responds to the combination of control factors.

15.Insulin is a protein that is produced by pancreatic cells and secreted into the bloodstream. Which of the following options correctly lists the order for the structures through which insulin passes from its production to its exit from the cell.

a. Rough ER, transport vesicles, Golgi apparatus, transport vesicles, cell membrane

b. Rough ER, lysosomes, transport vesicles, cell membranec. Rough ER, Golgi apparatus, smooth ER, cell membraned. Rough ER, transport vesicles, Golgi apparatus, vacuole, cell membrane.

16.Which of the following is the best reason the curve for the absorbance of light by chlorophyll a does not perfectly match the rate of photosynthesis?

a. The rate of photosynthesis is always fractionally slower than the rate of absorbance by chlorophyll a.

b. Chlorophyll a transmits light in the green and yellow parts of the spectrum and so the rate photosynthesis is low at those wavelengths.

c. There are fewer chlorophyll a molecules in the cell than the other molecules involved in photosynthesis, so chlorophyll a is the rate-limiting reagent.

d. Chlorophyll a is not the only photosynthetically important pigment in chloroplasts.

Questions 17 and 18 refer to the graphs above. The rate of reaction for three enzymes was calculated at different temperatures, and the rate of reaction for two additional enzymes was calculated at different pH levels. The results are shown in the following graphs. Assume that the y-axis share the same scale.

17.In enzymes 1, 2 and 3, why does the curve of the rate of reaction line for each enzyme drop sharply after the optimal temperature is reaches?

a. The increasing thermal energy of the solution denatures the enzyme, rapidly decreasing the rate of reaction.

b. The substrate is completely converted at the optimal temperature, and without substrate the rate of reaction decreases rapidly.

c. The optimal point of conversion by the enzyme results in a decreasing number of enzyme molecules due to molecular fatigue, resulting in a rapidly decreasing rate of reaction.

d. The final product of the enzyme conversion is a competitive inhibitor interfering at the active site of the enzyme, resulting in a rapidly decreasing rate of reaction.

18.How many times more acidic is the optimal environment for enzyme 4 that the optimal environment for enzyme 5?

a. 6b. 60c. 106

d. 108

19.A child is brought to the hospital with a fever of 1070 F. Doctors immediately order an ice bath to lower the child’s temperature. Which of the following statements offers the most logical explanation for this actions?

a. Elevated temperature will increase reaction rates in the child’s cells and overload the limited number of enzymes found in the cells of a small child.

b. Elevated body temperature may denature enzymes. c. Elevated body temperatures will increase the energy of activation

needed to start various chemical reactions in the body.d. Elevated body temperatures cause molecules to vibrated more quickly

and prevent enzymes from easily attaching to reactants. 20.Two individuals who are carriers for cystic fibrosis have three children

together. None of their children have cystic fibrosis. What is the probability that the couple’s fourth child will be born with cystic fibrosis?

a. 0%b. 25%c. 50%d. 75%

21.Which of the following mutations would be most likely to have a harmful effect on an organism/

a. A deletion of three nucleotides near the middle of the geneb. A single nucleotide deletion in the middle of an intronc. A single nucleotide deletion near the end of a coding sequenced. A single nucleotide insertion downstream of and close to the start of

the coding sequence.

22.An ATP-powered pump that transports a specific solute can indirectly drive the active transport of another solute in a mechanism called cotransport. This is shown in the figure above. The cotransporter protein is able to use the diffusion of H+ ions down their electrochemical gradient into the cell. By what process are the H+ ions being moved in this figures

a. Active transportb. Simple diffusionc. Facilitated diffusiond. Exocytosis

23.Based on the figure above, how might the rate of sucrose into the cell be increased?

a. Decrease the extracellular sucrose concentrationb. Decrease the extracellular pHc. Increase the cytoplasmic pHd. Make the membrane more permeable to hydrogen ions.

24.What is a G protein?a. A specific type of membrane receptor protein b. A protein on the cytoplasmic side of a membrane that becomes

activated by a receptor proteinc. A membrane-bound enzyme that converts ATP to cAMPd. A guanine nucleotide that converts between GDP and GTP to activate

and inactivate relay proteins.

25.Which of the following can activate a protein by transferring a phosphate group to it?

a. cAMPb. G-proteinc. Protein phosphatased. Protein kinase.

26.Which figure shows a water-soluble signaling molecule, and what is the evidence for this?

a. Figure A because the signaling molecule results in a response within the cytoplasm.

b. Figure A because the signaling molecule does not pass through the phospholipid bilayer

c. Figure B because the signaling molecule enters the cell to bind the receptor

d. Figure B because the activated receptor is able to enter the nucleus of the cell.

27.In figure A, which molecule represents the receptor protein and how does it function?

a. Molecule A is the receptor protein because it binds to the plasma membrane surface protein

b. Molecule B is the receptor protein, and molecule A is the ligand that binds it

c. Molecule C is the receptor protein, and it is lipid solubled. Molecule D is the receptor protein and once activate it initiates a

response.28.What is the basis for the difference in how the leading and lagging strands of

DNA molecules are synthesized?a. The origins of replication occur only at a 5’ end.b. Helicases and DNA polymerase work at the 5’ end.c. DNA polymerase can join new nucleotides only to the 3’ end of a

growing strandd. DNA ligase works only in the 3’ to 5’ direction.

29.In a population of squirrels, the allele that causes bushy tail (B) is dominant, while the allele that causes bald tail is recessive (b). If 64% of the squirrels have a bushy tail, what is the frequency of the dominant allele?

a. 0.8b. 0.6c. 0.4d. 0.36

30.Enzymes and energy are required for the synthesis of DNA and RNA. Which enzyme is correctly linked with its function?

a. Telomerase ensure that the transcription machinery starts with the codon AUG.

b. DNA ligase joins together Okazaki fragments from the lagging strand.c. DNA polymerase oversees the binding of mRNA to the ribosome.d. Helicase alters the new DNA strands so it will coil into a double helix.

Answers.1.A 2. D 3. D 4. D 5. C 6. C 7. D8. C 9. B 10. B 11. B 12. B 13. C 14. D15. A 16. D 17. A 18. C 19. B 20. B 21. D22. A 23. B 24. B 25. D 26. B 27. B 28. C29. C 30. B