Biology Exam 4 Practice Test 41 Questions with Verified Answers,100% CORRECT, Exams of Nursing

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Biology Exam 4 Practice Test 41 Questions with Verified

Answers

For this pair of items, choose the option that best describes their relationship. (A) The probability that amino acids with polar side chains are hydrophobic. (B) The probability that amino acids with side chains containing an -OH group are hydrophilic. A) Item (A) is greater than item (B). B) Item (A) is less than item (B). C) Item (A) is exactly or very approximately equal to item (B). D) Item (A) may stand in more than one of the above relations to item (B). - CORRECT ANSWER B All of the following contain amino acids EXCEPT A) hemoglobin. B) cholesterol. C) antibodies. D) enzymes. E) aquaporins. - CORRECT ANSWER B The bonding of two amino acid molecules to form a larger molecule requires which of

the following? A) removal of a water molecule B) addition of a water molecule C) formation of an ionic bond D) formation of a peptide bond E) both A and D - CORRECT ANSWER E Upon chemical analysis, a particular polypeptide was found to contain 300 amino acids. How many mRNA nucleotides were translated to create this protein? A) 901 B) 900 C) 300 D) 301 E) 100 - CORRECT ANSWER B Which type of interaction stabilizes the alpha helix and the beta pleated sheet structures of proteins? A) hydrophobic interactions B) nonpolar covalent bonds C) ionic bonds

D) hydrogen bonds E) peptide bonds - CORRECT ANSWER D The tertiary structure of a protein is the A) bonding together of several different polypeptide chains by weak bonds. B) order in which amino acids are joined in a polypeptide chain. C) unique three-dimensional shape created by bonds between R-groups. D) organization of a polypeptide chain into an alpha helix or beta pleated sheet. E) overall protein structure resulting from the aggregation of two or more polypeptide subunits. - CORRECT ANSWER C A hydrophilic R-group of an amino acid in hemoglobin would NOT be attracted to: A) the water molecules surrounding hemoglobin. B) a hydrophobic amino acid R group of hemoglobin. C) a charged amino acid R group of hemoglobin. D) a polar amino acid R group of hemoglobin. E) an amino acid R group of hemoglobin containing an -OH group. - CORRECT ANSWER B Altering which of the following levels of structural organization could change the function of a protein? A) primary

B) secondary C) tertiary D) quaternary E) all of the above - CORRECT ANSWER E The structural level of a protein least affected by a disruption in hydrogen bonding is the A) primary level. B) secondary level. C) tertiary level. D) quaternary level. E) All structural levels are equally affected. - CORRECT ANSWER A Humans can produce the amino acid alanine from other components in the body, but valine cannot be produced in the human body. From this you can conclude: A) Alanine is a non-essential amino acid B) Valine is a non-essential amino acid C) Valine is an essential amino acid D) A and B E) A and C - CORRECT ANSWER E

In sickle cell anemia, hemoglobin function is affected. WHY? A) The structure of hemoglobin remains unaffected, but its binding of oxygen is diminished. B) One hydrophilic amino acid in the primary structure is replaced by a different hydrophilic amino acid. C) One hydrophobic amino acid in the primary structure is replaced by a different hydrophobic amino acid. D) The final shape of the protein is altered, as are the shape of red blood cells. E) The sickle-shaped blood cells aggravate (worsen) the symptoms of malaria. - CORRECT ANSWER D Sickle cell anemia reduces a person's expected life span by, on average, 25- years. Which of the following is the BEST description of why natural selection has not removed sickle cell anemia from the human population? A) Sickle cell anemia is caused by a recessive allele B) Those with the aa genotype benefit from high survival due to malaria resistance C) Those with the AA genotype benefit from high survival due to malaria resistance

D) Heterozygotes for sickle cell anemia have the highest survival in non-malaria countries E) Heterozygotes for sickle cell anemia have the highest survival in malaria- stricken countries - CORRECT ANSWER E Which of the following is NOT a function of RNA in a normal animal cell? A) carrying amino acids to ribosomes for protein synthesis. B) serving as a component of ribosomes. C) acting as the template to create DNA. D) splicing of pre-mRNA. E) all of these are functions of RNA. - CORRECT ANSWER C Which of the following is NOT a difference between DNA and RNA? A) RNA nucleotides use a different phosphate than DNA nucleotides. B) One of RNA's nitrogenous bases is different than DNA's. C) DNA nucleotides contain a different sugar than RNA nucleotides. D) DNA is a double helix, but RNA is usually single-stranded. E) A and D are correct. - CORRECT ANSWER A A particular triplet of bases in the template strand of DNA is 3' CAT 5'. The corresponding codon for the mRNA transcribed is A) 3' CUA 5'.

B) 5' GUA 3'.

C) 5' UTC 3'.

D) 3'GAU 5'.

E) 3' CUU 5'. - CORRECT ANSWER B

The mRNA sequence for a certain polypeptide is 5'...GAGCCGUAA...3'. If the last A is changed to a U via a substitution mutation, what effect will this have on the protein? A) No change B) The polypeptide will be longer C) The polypeptide will undergo a frameshift D) The polypeptide will be shorter E) The polypeptide will definitely work better - CORRECT ANSWER B

20. Differential gene regulation means that different cell types have the same _______ but express different _______. A) proteins, mRNAs B) genomes, proteins C) mRNAs, genes D) genes, chromosomes

E) DNA, genomes - CORRECT ANSWER B Transcription in eukaryotes requires which of the following in addition to RNA polymerase? A) snRNA B) start and stop codons C) ribosomes and tRNA D) several transcription factors (TFs) E) aminoacyl synthetase - CORRECT ANSWER D Which of the following is not involved in mRNA processing? A) promoter B) spliceosomes C) 5' cap and poly (A) tail D) exons E) introns - CORRECT ANSWER A What are the coding segments of a stretch of eukaryotic RNA called? A) anticodons B) transposons C) introns D) exons

E) rightons - CORRECT ANSWER D Which of the following is NOT true about splicing? A) Splicing involves the removal of non-protein coding sequences B) Splicing involves the fusion of protein-coding sequences C) Splicing is done by the ribosome D) Splicing can generate different mRNAs from the same gene E) Splicing must occur before translation - CORRECT ANSWER C Which of the following is TRUE? A) RNA polymerase uses RNA as a template, and DNA polymerase uses a DNA template. B) RNA polymerase requires helicase to unzip the helix for it. C) RNA polymerase reads 5' to 3', but DNA polymerase reads 3' to 5'. D) RNA polymerase can initiate RNA synthesis without a primer, but DNA polymerase requires a primer. E) RNA polymerase does not need to separate the two strands of DNA in order to synthesize an RNA copy, whereas DNA polymerase must unwind the double helix before it can replicate the DNA. - CORRECT ANSWER D Put the following translation events in order:

i. elongation of the polypeptide ii. base pairing of methionine-tRNA to AUG of the mRNA iii. the larger ribosomal subunit binds to smaller ribosomal subunits iv. peptide bonding between the first two amino acids v. the small subunit of the ribosome recognizes and attaches to mRNA A) i, ii, iii, iv, v B) v, iv, iii, ii, i C) v, iii, ii, i, iv D) v, ii, iv, i, iii E) v, ii, iii, iv, i - CORRECT ANSWER E As a ribosome moves along an mRNA molecule by one codon, which of the following occurs? A) The tRNA that was in the P site moves into the A site B) The tRNA that was in the A site departs from the ribosome via a tunnel. C) The tRNA that was in the A site moves into the P site. D) The tRNA that was in the A site moves to the E site and is released. E) The polypeptide enters the E site. - CORRECT ANSWER C Which of the following mutations is least likely to be detrimental?

A) A substitution at the beginning of a gene B) A substitution at the end of a gene C) A deletion at the end of a gene D) An insertion at the end of a gene E) An insertion at the beginning of a gene - CORRECT ANSWER B Each of the following options is a modification of the sentence THECARWASRED. Which of the following is analogous to a frameshift mutation? A) CARWASRED B) THECARWARED C) THEREDWASCAR D) THERACWASRED E) THECARWASDED - CORRECT ANSWER B Which statement about prokaryotes is NOT true? A) Prokaryotic translation starts at AUG, which codes for methionine B) Prokaryotic mRNA receives a 5' cap before translation C) In prokaryotes, transcription and translation of an RNA molecule can occur at the same time D) Prokaryotic DNA includes a promoter for each gene

E) Prokaryotic ribosomes stop translating at one of three stop codons - CORRECT ANSWER B Which of the following is not a reason cells need to regulate their genes? A) To produce differentiated tissues and organs B) In some cases, not all of a cell's products are needed constantly. C) Single-celled bacteria often work together in colonies. D) It is a waste of energy to produce proteins that aren't needed. E) Some protein functions are mutually exclusive. - CORRECT ANSWER C What would happen if a scientist experimentally moved the trp repressible operator from its regular location in a prokaryote's operon to the end of the gene instead? A) The trp gene will not be transcribed. B) RNA polymerase will not be able to bind to the promoter. C) The repressor will no longer bind to the operator. D) The enhancer won't bind to the activators. E) The trp gene will be transcribed continuously. - CORRECT ANSWER E Spleen cells and kidney cells in one species of animal owe their differences in structure to A) having different genes expressed. B) having different genes.

C) having unique ribosomes. D) having different chromosomes. E) using different RNA polymerases. - CORRECT ANSWER A The human body regulates blood glucose levels via a negative feedback system. Which of the following would NOT be consistent with this process? A) When glucose levels are low, the body releases more glucose into the bloodstream from storage molecules. B) When glucose levels are high, the body releases more glucose into the bloodstream from storage molecules. C) When glucose levels are high, the body pulls glucose out of the bloodstream and puts them into storage. D) When glucose levels are high, the body feels full, triggering us to stop eating. - CORRECT ANSWER B Enhancers are used by ____ to regulate ____. A) eukaryotes, transcription. B) eukaryotes, translation. C) eukaryotes, mRNA splicing. D) prokaryotes, transcription. E) prokaryotes, translation. - CORRECT ANSWER A

In eukaryotes, general transcription factors A) bind to sequences downstream from the promoter during transcription. B) are required for the expression of specific protein-encoding genes. C) prevent RNA polymerase from binding to the promoter. D) help RNA polymerase bind to the promoter. E) usually lead to a high level of transcription even without additional specific transcription factors. - CORRECT ANSWER D

41. If you wanted to experimentally turn a human hair follicle cell into a muscle cell, what would the best way to do this? A) Replace the follicle cell's DNA with the muscle cell's DNA. B) Replace the follicle cell's activators with the muscle cell's activators. C) Insert a keratin (hair protein) repressor into the follicle cell. D) Insert an actin (muscle protein) repressor into the follicle cell. E) Ask it Nicely - CORRECT ANSWER B The bicoid protein is normally concentrated at the head end of an embryo. If large amounts of the product were injected into the tail end as well, which of the following would occur?

A) The embryo would grow to an unusually large size. B) The embryo would grow extra wings and legs. C) The embryo would probably show no head development and die. D) Head structures would form in both sides of the embryo. E) The embryo would develop normally. - CORRECT ANSWER D The hosts a virus can infect are determined by: A) the proteins on the virus surface and the host cell surface. B) whether the virus' nucleic acid is DNA or RNA. C) the proteins in the host's cytoplasm. D) the enzymes produced by the virus before it infects the cell. E) the enzymes carried by the virus. - CORRECT ANSWER A Which of the following is not a part of some or all viruses? A) nucleic acids B) a protein coat C) phospholipids D) glycoproteins E) ribosomes - CORRECT ANSWER E What is the name given to viruses with single-stranded RNA that acts as a template for

DNA synthesis? A) viroids B) bacteriophages C) proviruses D) retroviruses E) all viruses do this - CORRECT ANSWER D Which of the following places the events of the viral life cycle in the correct order? A) genome replication, capsid assembly, host cell entry B) host cell entry, genome replication, capsid assembly C) capsid assembly, release from host cell, genome replication D) genome replication, host cell entry, host cell release E) genome replication, host cell entry, protein synthesis - CORRECT ANSWER B Which of the following is/are characteristics of HIV? A) It carries its own reproductive enzymes for reverse transcription. B) It inserts its genetic material permanently into the host's genome. C) Its nucleic acid is DNA D) A and B E) All of the above - CORRECT ANSWER D

AZT is a nucleotide analog used to treat HIV. It is a nonfunctional thymine (T) nucleotide. Which step would AZT hamper in the reproductive cycle of the HIV virus? A) reverse transcription of DNA from RNA B) entry into the cell C) transcription of RNA from proviral DNA D) viral assembly within the cell - CORRECT ANSWER A