Adv Bio Ch. 17

Place the events in the synthesis of a polypeptide in the proper order.

1) small sub unit binds to mRNA and an initiator tRNA 2) the larger unit attaches to the small sub unit wight he initiator tRNA in the P site 3)an amino acid acetyl tRNA matches its anticodon to the codon in the A site 4)a peptide bond forms 5)a tRNA translocates from the A to the P site and an unattached tRNA leaves the ribosome from the outside

Which point mutation would most likely to have a catastrophic effect on the function of a protein?

A base deletion near the start of a gene

What would be the DNA strand that would code for phe-leu-ile-val? UUU-CUU-AUU-GUU

AAA-GAA-TAA-CAA

What is the energy source for translation?

ATP and GTP

Termination

After polymerase transcribes past the signal sequence pre mRNA is cut and released

Frameshift

Base pair insertions or deletions that are not multiples of three nucleotides. Produce nonfunctional proteins

Nonsense

Base pair substitution that creates a stop codon

Silent

Base pair substitution that doesn't change. Amino acid translation

Missense

Base pair substitution that results in the insertion of a different amino acid

mRNA

Carries the codon from DNA to ribosomes

Four steps of polypeptide synthesis:

Codon recognition Peptide Bond formation Translocation Termination

The template for transcription is _____.

DNA

Once transcribed, eukaryotic mRNA typically undergoes substantial alteration that includes what?

Excision of introns

A mutation in which part of a gene is likely to be the most damaging to a cell?

Exon

What are the coding segments of a stretch of eukaryotic DNA called?

Exons

What are polyribosomes?

Groups of ribosomes reading a single mRNA simultaneously

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

Hydrogen bonding between base pairs

A frameshift mutation could result from either ____ or ____ of the base.

Insertion.Deletion

What is the effect of a nonsense mutation in a gene?

Introduces a premature stop codon into the messenger RNA

Small nuclear RNA

Part of spliceosomes and plays a catalytic role in splicing pre messenger RNA

rRNA

Performs catalytic functions at the binding site

What is the product of translation?

Polypeptide

What is the product of transcription?

Pre mRNA

During splicing, which molecular component of the spliceosome catalyzes the excision reaction?

RNA

The template for translation is _____.

RNA

Elongation

RNA polymerase II moves along the strong connecting RNA nucleotides

Explain the redundancy and the wobble phenomenon.

Redundancy- several triplets may code for the same amino acid to make sure one is available

What is the energy source for transcription?

Ribonucleoside triphosphate

Initiation

Transcription factors binded to a promoter factor and polymerase II separates DNA strands

tRNA

Transfer. Carries amino acid to its position on the polypeptide

If the triple of bases coding in DNA is AAA. What is the anticodon on tRNA?

UUU

What is a ribozyme?

an RNA with enzymatic activity

What is the most abundant type of RNA?

rRNA (ribosomal)