Gene expression

Which of the following describes the movement of RNA polymerase during transcription most accurately?

3' → 5' along the template DNA strand

There are 61 mRNA codons that specify amino acids, but only 45 tRNA anticodons. Which of the following correctly describes this difference in numbers?

A single tRNA anticodon can bind to more than one mRNA codon

In comparing DNA replication and transcription, which of the following is not true?

DNA replication begins at the origin of replication, whereas transcription begins at the start codon.

The P site of a ribosome does which of the following?

It holds the tRNA carrying the growing polypeptide chain.

Using the codon table, what would be the predicted amino acid sequence generated by the following template DNA sequence? 5' CAA-GGA-TAA-CGA-AGA-CAT 3'

N-met-ser-ser-leu-ser-leu-C how?: -you tracribe to : 3' GUU CCU AUU GCU UCU GUA 5' -flip to 5'-> 3' 5' AUG UCU UCG UUA UCC UUG 3' -translate now N(5') met ser ser leu ser leu C(3')

Which of the following best describes the termination of transcription in bacteria?

RNA polymerase transcribes through the TERMINATOR SEQUENCE, causing the polymerase to separate from the DNA and release the transcript

In comparing gene expression in eukaryotes and bacteria, which of the following is true?

The genetic code is shared between bacteria and eukaryotes.

Which of the following descriptions about translation in eukaryotic cells is correct?

all polypeptides are first synthesized on free ribosomes

Which of the following correctly describes exon shuffling?

it enables the formation of new genes

A transcription unit that is 8,000 nucleotides long may use 1,200 nucleotides to make a protein consisting of approximately 400 amino acids. Which best describes the difference in the length of sequences between the transcription unit and coding sequence?

many noncoding stretches of nucleotides are present in mRNA.

Which of the following refers to when a point mutation changes an amino acid codon into a stop codon?

nonsense mutation

How do cells distinguish proteins destined for secretion or for segregation to specific intracellular compartments from those that will remain in the cytoplasm?

some proteins, as they begin synthesis, contain a signal region that causes the ribosome with its growing polypeptide to attach to the ER and translocate the polypeptide into the lumen of the ER