Chapter 17 - APBIO

What is the 'one gene-one polypeptide' hypothesis?

The idea that each gene codes for a single polypeptide (protein).

What are transcription and translation?

Transcription is the synthesis of RNA under the direction of DNA. Translation is the synthesis of a polypeptide under the direction of mRNA.

What is a codon?

A three-nucleotide sequence in mRNA that codes for a specific amino acid or stop signal.

What is the wobble hypothesis?

The idea that the third nucleotide in many codons is less important for specifying the correct amino acid, allowing more flexibility in base pairing.

What is the function of RNA polymerase?

It pries DNA apart and hooks RNA nucleotides together based on the DNA code.

What is the transcription initiation complex?

The assembly of RNA polymerase and transcription factors at the promoter region of a gene to begin transcription.

What are the three main modifications made to eukaryotic mRNA?

1. Addition of 5' cap, 2) Addition of 3' poly-A tail, 3) RNA splicing to remove introns.

What is alternative RNA splicing?

The process by which different combinations of exons from a single gene can be joined to produce multiple mRNA and protein variants.

What are the three main sites on a ribosome during translation?

P site (peptidyl), A site (aminoacyl), and E site (exit).

What are the three main stages of translation?

Initiation, elongation, and termination.

What is a frameshift mutation?

A mutation caused by the insertion or deletion of nucleotides that alters the reading frame of the genetic code.

What is a silent mutation?

A base-pair substitution that does not affect the amino acid sequence of the protein.

Name three types of RNA and their functions.

mRNA (carries genetic information), rRNA (part of ribosomes), tRNA (carries amino acids during translation).