Biology Exam 4 Practice

13. What amino acid sequence will be generated based on the following mRNA codon sequence? 5′-AUG-UCU-GCG-3′ a. Ala-Ser-Met b. Val-Ser-Ala c. Start-Ser-Gly d. Met-Ser-Ala

D

15. Which of the following molecules is a protein produced by a regulatory gene? a. operon b. operator c. promoter d. repressor

D

11. A particular triplet of bases in the template strand of DNA is 5′-AGT-3′. What would be the corresponding codon for the mRNA that is transcribed? a. 3′-UCA-5′ b. 3′-ACU-5′ c. 5′-AGT-3′ d. 5′-UCA-3′

A

12. An mRNA molecule with the sequence 5′-CCG-ACG-3′is being read by a ribosome. During translation which of the following tRNA anticodons will be the first to productively bind with this mRNA? a. 3′-GGC-5′ b. 5′-GGC-3′ c. 5′-UGC-3′ d. 3′-UGC-5′

A

14. Muscle cells differ from nerve cells mainly because they ________. a. express different genes b. contain different genes c. use different genetic codes d. have unique ribosomes

A

28. Which of the following structural features of the digestive system improves the efficiency of exchange of energy and materials with the environment? a. more branching or folds b. increased thickness c. larger cells d. decreased blood supply

A

6. Which of the following processes will occur at the exposed 3′ end of a tRNA molecule? a. An amino acid will bind covalently. b. The single stranded nucleotides (ACCA) will be removed to stabilize the tRNA. c. The small and large subunits of the ribosome will attach to the 3" end. d. The 5′ cap of the mRNA will bind covalently.

A

1. Which statement correctly compares the primary transcript in the nucleus of a eukaryotic cell with the functional mRNA? a. the primary transcript is the same size as the mRNA b. the primary transcript is longer than the mRNA c. the primary transcript is shorter than the mRNA d. both the primary transcript and mRNA contain introns

B

16. Gene regulation is BEST described as the way in which a cell a. Controls whether mRNA or DNA is used as a transcript b. Controls which genes products are being created by the cell c. Controls DNA synthesis d. Controls the distribution of chromosomes into gametes

B

18. When a active regulatory molecule must be bound to a region of the DNA (such as promoter) in order for transcription to occur, this is an example of: a. temporal control b. positive control c. negative control d. feedback inhibition

B

2. Which of the following processes occurs as part of transcription? a. DNA is replicated b. RNA is synthesized c. proteins are synthesized d. mRNA attaches to ribosomes

B

21. Under what conditions does the trp repressor block transcription of the trp operon? a. when the repressor binds to the inducer b. when the repressor binds to tryptophan c. when the repressor is not bound to RNA polymerase d. when the repressor is not bound to the operator

B

24.The functioning of enhancers is an example of ________. a. a eukaryotic equivalent of prokaryotic promoter functioning b. transcriptional control of gene expression c. the stimulation of translation by initiation factors d. post-translational control that activates certain proteins

B

3. Which of the following molecular structures contains codons? a. a protein b. mRNA c. tRNA d. rRNA

B

31. Which type of muscle directly helps move food along the digestive tract? a. cardiac muscle b. smooth muscle c. striated muscle d. skeletal muscle

B

33. Which body system assists with coordination of vertebrate body functions via chemical signals? a. respiratory system b. endocrine system c. integumentary system d. excretory system

B

34. Which of the following is a characteristic of nervous system signals? a. They allow gradual changes to take place in the body. b. They travel quickly throughout the body. c. They usually impact the entire body. d. They require a voltage change to be transmitted.

B

39. The temperature-regulating center of vertebrate animals is located in the ________. a. thyroid gland b. hypothalamus c. subcutaneous layer of the skin d. liver

B

5. Which component is directly involved in translation? a. RNA polymerase b. ribosome c. spliceosome d. DNA

B

9. A single base substitution mutation is likely to have a less harmful effect when the base change results in which of the following? a. a stop codon b. a codon that specifies the same amino acid as the original codon c. an amino acid substitution that alters the tertiary structure of the protein d. an amino acid substitution at the active site of an enzyme

B

10. Which of the following statements describes the effect of a nonsense mutation on a gene? a. It changes only one amino acid in the encoded protein. b. It has no effect on the amino acid sequence of the encoded protein. c. It introduces a premature stop codon into the mRNA. d. It alters the reading frame of the mRNA

C

19. If RNA polymerase cannot bind to the DNA upstream of the coding sequence of a gene a. the coding sequence is termed an operator b. DNA polymerase initiates transcription of the mRNA instead c. transcription cannot occur and the gene product cannot be made d. transcription is enhanced and more gene product is made

C

20. Which of the following conditions is most likely to result in transcription of the lac operon? a. There is more glucose in the cell than lactose. b. There is glucose but no lactose in the cell. c. The cAMP and lactose levels are both high within the cell. d. The cAMP level is high and the lactose level is low.

C

22. DNA methylation and histone acetylation are examples of which of the following processes? a. genetic mutation b. chromosomal rearrangements c. regulation of gene expression d. translocation

C

25. Which of the following is an example of post-transcriptional control of gene expression? a. the addition of methyl groups to cytosine bases of DNA b. the binding of transcription factors to a promoter c. the removal of introns and alternative splicing of exons d. gene amplification contributing to cancer

C

27. The body's automatic tendency to maintain a constant and optimal internal environment is termed as ________. a. balanced equilibrium b. physiological chance c. homeostasis d. static equilibrium

C

32. Which type of cell is specialized to store fat in animals? a. bone cells b. muscle cells c. adipose cells d. red blood cells

C

35. Which of the following increases the rate of heat exchange between an animal and its environment? a. feathers or fur b. vasoconstriction c. wind blowing across the body surface d. a blubber or fat layer

C

37. In a cool environment, an ectotherm is more likely to survive an extended period of food deprivation than would an equally sized endotherm because the ectotherm ________. a. maintains a higher basal metabolic rate b. expends more energy per kilogram of body mass than does the endotherm c. invests little energy in temperature regulation d. has greater insulation on its body surface

C

4. Transcription in eukaryotes requires which of these molecules in addition to DNA? a. tRNA b. ribosomes c. RNA polymerase d. aminoacyl-tRNA synthetase

C

7. Which of the following molecules carries information from DNA and directs incorporation of amino acids at the ribosome? a. enzymes b. rRNA c. mRNA d. tRNA

C

17. Which of these is NOT true of operons a. It includes a set of genes that function together b. Genes in the operon are transcribed together into one mRNA c. Genes in the operon share a single promoter d. Operons are regions of the ribosome that translate regulatory proteins

D

23. Which of the following methods are used by eukaryotes to control gene expression but are NOT used by bacteria? a. organization of genes in operons b. limiting access to free nucleic acids c. regulatory proteins binding to promoter sequences and determining polymerase use d. control of both RNA splicing and chromatin

D

26. Which of the following processes is the best way to determine whether alternative splicing of a given gene occurs? a. Compare the size of the DNA within the given gene and a similar gene in a related organism. b. Compare the sequences of the given gene and a gene known to undergo alternative splicing. c. Isolate the primary transcripts made from the given gene and compare the sequences. d. Isolate mRNA from the given gene and compare the sequences.

D

29. What tissue lines most exchange surfaces of multicellular animals? a. connective tissue b. smooth muscle c. neural tissue d. epithelial tissue

D

30. Which of the following is a typical characteristic of connective tissues? a. little space between the membranes of adjacent cells b. the ability to transmit electrochemical impulses c. the ability to shorten upon stimulation d. relatively few cells and a large amount of extracellular matrix

D

36. Elephants can often be observed using their trunks to spray water over their bodies, which cools them. What type of heat exchange does this process promote? a. conduction b. convection c. radiation d. evaporation

D

38. The panting responses observed in overheated birds and mammals dissipate heat loss by what process? a. countercurrent exchange b. acclimation c. vasoconstriction d. evaporation

D

40. Which of these provides the best advantage for an animal that conforms to a changing environmental condition, such as temperature? a. The animal is more likely to sleep during the day. b. The animal's internal temperature changes opposite to the change in the external temperature. c. The animal spends more time looking for food. d. The animal spends less energy regulating its internal temperature.

D

8. Which answer correctly compares prokaryotic and eukaryotic codons? a. Prokaryotic codons usually contain different bases than those of eukaryotes. b. Prokaryotic codons usually specify different amino acids than those of eukaryotes. c. Organism within a phylum share codons that are distinct from organisms in other phyla. d. Organisms utilize codons that are nearly universal among all organisms.

D