Biology Chapter 17

The nitrogenous base adenine is founf in all members of which group?

ATP, RNA, and DNA

We now know that the one gene-one enzyme hypothesis is not entirely accurate because

Many genes code for proteins that are not enzymes; a single gene codes for a single polypeptide chain, and many enzymes are made up of more than one polypeptide chain; many genes code for RNA molecules that have no enzymatic activity. (A, B, and C)

RNA polymerase and DNA polymerase differ in that

RNA polymerase can initiate RNA synthesis, but DNA polymerase requires a primer to initiate DNA synthesis.

What type of bonding is responsible for maintaining the shape of the tRNA molecule?

hydrogen bonding between base pairs

If the triplet CCC codes for the amino acid proline in bacteria, then in plants CCC should code for

proline (same)

A mutant bacterial cell has a defective aminoacyl synthetase that attaches a lysine to tRNAs with the anticodon AAA instead of phenylalanine. The consequence of this for the cell will be that

proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU

Which of the following is least related to the other items?

signal-recognition particles (SRPs) other ones: exons, introns, RNA splicing, mRNA

An extraterrestrial life form is discovered. It has a genetic code much like that of organisms on Earth except that there are 5 different DNA bases instead of 4 and the base sequences are translated as doublets instead of triplets. How many different amino acids could be accommodated by this genetic code?

25

*given a codon table* A possible sequence of nucleotides in the template strand of DNA that would code for the polypeptide sequence phe-leu-ile-val would be

3' AAA-GAA-TAA-CAA 5'

RNA polymerase moves along the template strand of DNA in the ____ direction, and adds nucleotides to the ____ end of the growing transcript.

3' to 5'; 3'

The enzyme polynucleotide phosphorylase randomly assembles nucleotides into a polynucleotide polymer. You add polynucleotide phosphorylase to a solution of adenosine triphosphate and guanosine triphosphate. The resulting artificial mRNA molecule will have ____ possible different codons if the code involved two base-sequences and _____ possible different codons if the code involved three base-sequences.

4; 8

*given a codon table* A peptide sequence has the sequence NH2-phe-pro-lys-gly-phe-pro-COOH. Which of the following sequences in the coding strand of the DNA codes for this peptide?

5' TTT-CCC-AAA-GGG-TTT-CCC

Which of the following helps to stabilize mRNA by inhibiting its degradation?

5' cap and poly-A tail (both C and D)

During translation, chain elongation continues until what happens?

A stop codon is encountered

As a ribosome translocated along an mRNA molecule by one codon, which of the following occurs?

The tRNA that was in the A site moves into the P site; The tRNA that was in the P site moves to the E site and is released. (Both A and C are correct)

Which of the following does not occur during the termination phase of translation?

a tRNA with the next amino acid enters the P site.

From the following list, which is the first event in translation in eukaryotes?

base pairing of activated methionine-tRNA to AUG of the messenger RNA

Which of the following are transcribed from DNA?

exons and rRNA (B and C only)

All of the following are found in prokaryotic mRNA except

introns (others were the AUG codon, the UGA codon, uracil, cytosine)

Which of the following is not directly involved in the process of translation?

ligase

Which of the following is least related to the other items?

other ones: TATA box, transcription, template strand, RNA polymerase answer: translation

What is the sequence of a peptide based on the mRNA sequence 5'UUUUCUUAUUGUCUU 3'?

phe-ser-tyr-cys-leu

Of the following types of mutations, which one is likely to be the most common?

point mutation

Once transcribed, eukaryotic mRNA typically undergoes substantial alteration that includes

the excision of introns

Where is eukaryotic ribosomal RNA transcribed?

the nucleolus