Bio Exam 3 masteringbiology HW

Why are ribonucleoside triphosphates the monomers required for RNA synthesis rather than ribonucleoside monophosphates? a. Ribonucleoside triphosphates have high potential energy, making the polymerization reaction exergonic. b. Ribonucleoside triphosphates have low potential energy, making the polymerization reaction endergonic. c. Only ribonucleoside triphosphates contain the sugar ribose. d. Ribonucleoside monophosphates cannot form complementary base pairs with the DNA template.

a. Ribonucleoside triphosphates have high potential energy, making the polymerization reaction exergonic.

What is meant by translocation? a. The ribosome slides one codon down the mRNA. b. The two ribosomal subunits are joined in a complex. c. The polypeptide chain grows by one amino acid. d. The completed polypeptide is released from the ribosome.

a. The ribosome slides one codon down the mRNA.

A knock-out allele is ______. a. a mutated form of a gene that does not make a functioning product b. a mutated form of a gene that creates proteins with additional segments c. a wild-type (normal) form of a gene that produces a protein with increased activity d. a wild-type (normal) form of a gene that is difficult to detect e. a mutated form of a gene that creates proteins with additional functions

a. a mutated form of a gene that does not make a functioning product

A promoter is ______. a. a sequence in DNA that brings RNA polymerase near the site for transcription b. one or more eukaryotic proteins that bind to DNA near the start of a gene c. a protein that associates with bacterial RNA polymerase to help it bind to DNA d. a sequence in RNA that promotes the release of RNA polymerase from DNA

a. a sequence in DNA that brings RNA polymerase near the site for transcription

Translation occurs in the _____. a. cytoplasm b. lysosome c. nucleus d. Golgi apparatus e. nucleoplasm

a. cytoplasm

After DNA replication is completed, _____. a. each new DNA double helix consists of one old DNA strand and one new DNA strand b. each new DNA double helix consists of two new strands c. each of the four DNA strands consists of some old strand parts and some new strand parts d. there are four double helices e. one DNA double helix consists of two old strands and one DNA double helix consists of two new strands

a. each new DNA double helix consists of one old DNA strand and one new DNA strand

The first step in the replication of DNA is catalyzed by _____. a. helicase b. primase c. DNA polymerase d. ligase e. single-strand binding protein

a. helicase

The primers used for DNA synthesis are ______. a. short RNA sequences b. proteins that bind to single-stranded DNA c. short amino acid sequences (peptides d. RNA polymerases e. short DNA sequences

a. short RNA sequences

Spliceosomes are composed of _____. a. snRNPs and other proteins b. polymerases and ligases c. introns and exons d. the RNA transcript and protein e. snRNPs and snurps

a. snRNPs and other proteins

The direction of synthesis of an RNA transcript is _____. a. 1' —> 5' b. 5' —> 3' c. 1' —> 3' d. 3' —> 5' e. 2' —> 4'

b. 5' —> 3'

At which site do new aminoacyl tRNAs enter the ribosome during elongation? a. E-site b. A-site c. P-site d. B-site

b. A-site

Two important checkpoints that regulate the cell's progression through the cell cycle occur in the _____ and _____ phases of the cell cycle. a. prophase, telophase b. G1, G2 c. G1, S d. S, M

b. G1, G2

How did the P site of the ribosome get its name? a. It is the site occupied by incoming aminoacyl tRNAs. b. It is where the polypeptide chain attached to the tRNA is transferred to the aminoacyl tRNA for peptide-bond formation. c. It is where amino acids are joined to tRNAs, producing aminoacyl tRNAs. d. In this site the tRNA no longer has an amino acid attached and is about to exit the ribosome.

b. It is where the polypeptide chain attached to the tRNA is transferred to the aminoacyl tRNA for peptide-bond formation.

Which part of a deoxynucleoside triphosphate (dNTP) molecule provides the energy for DNA synthesis? a. Sugar b. Phosphate groups c. Free 3' hydroxyl (-OH) group d. Base

b. Phosphate groups

Which of the following statements about DNA synthesis is true? a. DNA polymerase adds dNTP monomers in the 3' to 5' direction. b. Primers are short sequences that allow the initiation of DNA synthesis. c. Nucleotides are added in a random fashion to single-stranded DNA. d. As DNA polymerase moves along the template strand, each new nucleotide provides a 5' hydroxyl group for the next reaction to occur

b. Primers are short sequences that allow the initiation of DNA synthesis.

Where does translation take place? a. Golgi apparatus b. Ribosome c. Endoplasmic reticulum d. Nucleus

b. Ribosome

During RNA processing a(n) _____ is added to the 3' end of the RNA. a. 3' untranslated region b. a long string of adenine nucleotides c. 5' untranslated region d. coding segment e. modified guanine nucleotide

b. a long string of adenine nucleotides

The RNA segments joined to one another by spliceosomes are _____. a. caps b. exons c. snRNPs d. tails e. introns

b. exons

Which of the following damages cells and causes cell aging? a. exercise b. inflammation c. reducing stress d. all of the above

b. inflammation

A point mutation that results in the substitution of one amino acid for another within a protein is a ______. a. silent mutation b. missense mutation c. deleterious mutation d. neutral mutation e. beneficial mutation

b. missense mutation

5' caps and 3' poly(A) tails of eukaryotic mRNAs ______. a. protect mRNA from degradation and enhance transcription b. protect mRNA from degradation and enhance translation c. mark the beginning and end of introns, respectively d. act as sites for the start and stop of translation, respectively

b. protect mRNA from degradation and enhance translation

What is the function of DNA polymerase I? a. synthesis of a short RNA, complimentary to single-stranded DNA b. removing primers and synthesizing a short section of DNA to replace them c. synthesis of the short section of double-stranded DNA required by DNA polymerase d. closing the gap at the 3' end of DNA after excision repair

b. removing primers and synthesizing a short section of DNA to replace them

In DNA replication, a. the original strands remain together. b. the replica strands are complementary to the templates. c. each replica strand has the same base sequence as its template. d. DNA copies itself. e. both (b) and (d).

b. the replica strands are complementary to the templates.

A diploid species has ten different types of chromosomes. A haploid cell of this species contains how many chromosomes? a. Not enough information b. 20 c. 10 d. 5

c. 10

What catalyzes DNA synthesis? a. dNTPs b. Replication fork c. DNA polymerase d. Primer

c. DNA polymerase

Which of the following steps occurs last in the initiation phase of translation? a. An aminoacyl tRNA binds to the start codon. b. A peptide bond is formed between two adjacent amino acids. c. The large ribosomal subunit joins the complex. d. The small subunit of the ribosome binds to the 5' cap on the mRNA.

c. The large ribosomal subunit joins the complex.

Where are okazaki fragments found? a. only on the leading strand b. only at the origin of replication c. only on the lagging strand d. only within primase e. only in front of the replication fork

c. only on the lagging strand

Telomerase is needed to ______. a. create repetitive DNA sequences that allow the assembly of the kinetochore b. allow DNA replication at the ends of chromosomes to occur in the 3' to 5' direction c. prevent the loss of DNA bases at the ends of linear chromosomes d. open the two strands of DNA in front of the replication fork e. synthesize telomere proteins

c. prevent the loss of DNA bases at the ends of linear chromosomes

The action of helicase creates _____. a. primers and replication bubbles b. primers and DNA fragments c. replication forks and replication bubbles d. DNA fragments and replication forks e. DNA fragments and replication bubbles

c. replication forks and replication bubbles

The polarity of a DNA strand refers to the fact that _________________________. a. the two ends of the strand have the same chemical group b. DNA lacks an OH group at one position of the ribose sugar c. the two ends of the strand have different chemical groups d. when two DNA strands pair they run in the same direction e. only A and T and G and C pairs form

c. the two ends of the strand have different chemical groups

During transcription, in which direction is (1) RNA synthesized and in which direction is (2) the DNA template "read"? During transcription, in which direction is (1) RNA synthesized and in which direction is (2) the DNA template "read"? a. (1) 3'—>5' (2) 5'—>3' b. (1) 3'—>5' (2) 3'—>5' c. (1) 5'—>3' (2) 5'—>3' d. (1) 5'—>3' (2) 3'—>5'

d. (1) 5'—>3' (2) 3'—>5'

The Hershey-Chase experiment answered the question of whether protein or DNA was the genetic material by learning whether ______. a. DNA could be radioactively labeled using 32P b. DNA or protein migrated at the same or different rates when centrifuged c. enzymes that destroyed DNA or destroyed protein prevented transformation of bacteria d. DNA or protein from a virus entered bacterial cells during infection e. protein could be radioactively labeled using 35S

d. DNA or protein from a virus entered bacterial cells during infection

Topoisomerase works to _______________. a. recognize origins of replication and open a replication bubble at these sites b. incorporate new DNA building blocks in the growing DNA strand c. incorporate new RNA building blocks at the beginning of a chain d. prevent twisting of DNA in front of the replication fork e. open up the two strands of DNA at the replication fork

d. prevent twisting of DNA in front of the replication fork

Beginning within the nucleus, the first step leading to the synthesis of a polypeptide is _____. a. removal of introns from RNA and the stitching together of exons b. translation of a DNA nucleotide sequence into a sequence of amino acids c. translation of an RNA nucleotide sequence into a sequence of amino acids d. transferring of information from DNA to messenger RNA e. linking of nucleotides to form a polypeptide

d. transferring of information from DNA to messenger RNA

The synthesis of a new strand begins with the synthesis of a(n) _____. a. short pieces of DNA b. single-strand binding protein c. poly(A) tail d. Okazaki fragment e. RNA primer complementary to a preexisting DNA strand

e. RNA primer complementary to a preexisting DNA strand

DNA polymerases use _________ as their substrates. a. ribonucleotide triphosphates (rNTPs) b. four different nitrogenous bases c. deoxyribonucleoside monophosphates (dNMPs) d. the 5' end of a preexisting DNA strand e. deoxyribonucleoside triphosphates (dNTPs)

e. deoxyribonucleoside triphosphates (dNTPs)

During RNA processing a(n) _____ is added to the 5' end of the RNA. a. 3' untranslated region b. a long string of adenine nucleotides c. 5' untranslated region d. coding segment e. modified guanine nucleotide

e. modified guanine nucleotide

The karyotype of a trisomic individual is symbolized as ____. a. 2n+1 b. 2n-1 c. 3n d. n+1

a. 2n+1

What would be the consequence(s) for DNA synthesis if primase were defective? a. Both leading and lagging strand synthesis would be incomplete. b. Both leading and lagging strand synthesis would be unaffected. c. Leading strand synthesis would be incomplete; lagging strand synthesis would be unaffected. d. Lagging strand synthesis would be incomplete; leading strand synthesis would be unaffected.

a. Both leading and lagging strand synthesis would be incomplete.

Why is the new DNA strand complementary to the 3' to 5' strands assembled in short segments? a. DNA polymerase can assemble DNA only in the 5' to 3' direction b. it is more efficient than assembling complete new strands c. only short DNA sequences can extend off the RNA primers d. DNA polymerase can assemble DNA only in the 3' to 5' direction e. the replication forks block the formation of longer strands

a. DNA polymerase can assemble DNA only in the 5' to 3' direction