DNA Structure
A nucleotide is composed of these three things.
What is a phosphate group, a pentose sugar, and a nitrogenous base?
This enzyme is a key player in DNA replication, by synthesizing the new DNA strand, as well as checking it for errors.
What is DNA polymerase?
This is the name for a "nucleotide triplet" that corresponds to a specific amino acid.
What is a codon?
During translation, this is the site of the ribosome where the growing polypeptide chain is built.
a) A site
b) E site
c) P site
d) None of the above
What is the P site?
During DNA Replication, nucleic acids are assembled in the ___ to ____ direction.
What is the 5' to 3' direction?
Which of these nitrogenous bases is found in DNA but not in RNA?
a) Adenine
b) Cytosine
c) Uracil
d) Thymine
d) Thymine
In many cases, more than one codon codes for the same amino acid. Because of this, we say that the code is __________.
a) inaccurate
b) incomplete
c) not specific
d) redundant
e) tricky
d) redundant
In a eukaryotic cell, transcription takes place __________.
a) on the cell membrane
b) in the rough endoplasmic reticulum
c) in the cytoplasm
d) on free ribosomes
e) in the nucleus
e) in the nucleus
What kind of chemical bond is found between paired bases of the DNA double helix?
a. covalent
b. hydrogen
c. sulfhydryl
d. phosphate
e. ionic
b. hydrogen
During DNA replication, this enzyme helps to prevent overwinding of the DNA as it is unraveled.
a) DNA polymerase
b) Helicase
c) Topoisomerase
d) Ligase
e) Primase
c) Topoisomerase
tRNA during protein synthesis is used to __________ .
a) Deliver amino acids to their proper site during protein synthesis
b) Attach mRNA to the small subunit of the ribosome
c) Guide ribosomal subunits out of the nucleus through the nuclear pores
d) Process mRNA
a) Deliver amino acids to their proper site during protein synthesis
During translation, amino acid elongation occurs until __________ .
a) All tRNAs are empty
b) The ribosome encounters a “stop” codon
c) The polypeptide is long enough
d) No further amino acids needed by the cell
b) The ribosome encounters a “stop” codon
These short sections of DNA are synthesized on the lagging strand of the replicating DNA.
What are Okazaki Fragments?
What determines the nucleotide sequence of the newly synthesized strand during DNA replication?
a. the arrangement of histones in the sugar phosphate backbone
b. the relative amounts of the four nucleoside triphosphates in the cell
c. the nucleotide sequence of the template strand
d. the primase used in the reaction
c. the nucleotide sequence of the template strand
One strand of a DNA molecule has the following sequence: 3′-AGTACAAACTATCCACCGTC-5′. In order for that strand to be transcribed, there would have to be a specific recognition sequence, called a(n) __________, to the left of the DNA sequence indicated.
a) intron
b) promoter
c) AUG codon
d) exon
e) centromere
b) promoter
During translation in a eukaryotic cell, __________.
a) ribosomes move into the nucleus
b) tRNA carries amino acid molecules to the nucleus, where they are added to a growing polypeptide chain
c) polypeptides are synthesized at ribosomes, according to instructions carried by mRNA
d) mRNA is synthesized by the bonding of free nucleotides to the bases on the template strand of DNA
e) ribosomes move out of the nucleus
c) polypeptides are synthesized at ribosomes, according to instructions carried by mRNA
Guanine makes up 38% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be adenine?
a. 31
b. 24
c. 38
d. 12
e. It cannot be determined from the information provided.
d. 12%
At a specific area of a chromosome, the sequence of nucleotides below is present where the chain opens to form a replication fork: 3' T G C A A T C C 5' An RNA primer is formed from this template. Which of the following represents the primer sequence?
a. 3' G C C T A G G 5'
b. 5' G C C U A G G 3'
c. 5' A C G U U A G G 3'
d. 5' A C G T T A G G 3'
e. 5' G C C T A G G 3'
c. 5' A C G U U A G G 3'
What is a key difference with eukaryotic and prokaryotic gene expression?
a) RNA polymerase is only involved in eukaryotic gene expression
b) In prokaryotes, the RNA transcript is immediately available as mRNA and does not require processing
c) In eukaryotes, the RNA sequences function as termination signals
d) In prokaryotes, proteins are made directly from DNA, not RNA
e) All of the above.
b) In prokaryotes, the RNA transcript is immediately available as mRNA and does not require processing
Which of the following statements correctly describes mRNA processing?
a) Introns are cut out of the primary transcript and spliced together at the end of the transcript.
b) Exons are cut out of the primary transcript, and the introns are spliced together.
c) Introns are cut out of the primary transcript, and the resulting exons are spliced together.
d) Exons are cut out of the primary transcript and transported to the endoplasmic reticulum.
e) Introns are cut out of the primary transcript and transported to the ribosomes.
c) Introns are cut out of the primary transcript, and the resulting exons are spliced together.