BIOL 1710 CH15 & CH16

These flashcards cover key concepts of protein synthesis, transcription, translation, gene regulation, and the roles of different types of RNA.

What is the process of converting DNA to RNA called?

Transcription.

What is the role of mRNA in protein synthesis?

mRNA carries the genetic code from the DNA to the ribosome for protein synthesis.

What are codons?

Codons are sequences of three nucleotides in mRNA that correspond to specific amino acids.

What initiates transcription in prokaryotes?

A promoter region where RNA polymerase binds before starting transcription.

How does transcription differ between prokaryotes and eukaryotes?

In prokaryotes, transcription occurs in the cytoplasm, while in eukaryotes, it occurs in the nucleus.

What do introns and exons refer to in mRNA processing?

Introns are non-coding regions that are removed, while exons are coding regions that are retained.

What is the role of a spliceosome?

A spliceosome removes introns and joins exons together in mRNA processing.

What is the significance of a 5' cap and a poly-A tail in mRNA?

They protect mRNA from degradation and assist in translation.

What is the function of tRNA during translation?

tRNA carries amino acids to the ribosome and matches its anticodon with the codon on mRNA.

What is a stop codon?

A codon that signals the end of protein synthesis and does not code for any amino acid.

What is gene expression?

The process of transcribing and translating genes into proteins.

What is an operon?

A cluster of genes under the control of a single promoter, allowing coordinated expression.

What is the role of a repressor in gene regulation?

A repressor blocks transcription of a gene when bound to the operator region.

How can lactose induce gene expression in bacteria?

The presence of lactose binds to the repressor, allowing transcription of lactose-digesting genes.

What is alternative splicing?

The process by which different exons are combined to produce various protein variants from a single gene.

What are the three main types of RNA involved in protein synthesis?

mRNA (messenger RNA), tRNA (transfer RNA), and rRNA (ribosomal RNA).

What is the significance of the codon AUG?

AUG is the start codon that codes for the amino acid methionine.

What distinguishes RNA nucleotides from DNA nucleotides?

RNA contains Uracil (U) instead of Thymine (T), along with Adenine (A), Guanine (G), and Cytosine (C).

During transcription elongation, in which direction is the DNA template strand read, and in which direction is the mRNA synthesized?

The DNA template is read in a 3' to 5' direction, while mRNA synthesis occurs in a 5' to 3' direction.

How is transcription typically terminated in prokaryotes?

Termination can involve the formation of a hairpin loop in the newly synthesized RNA, which causes the RNA polymerase to dissociate.

What unique aspect characterizes the timing and location of transcription and translation in prokaryotes compared to eukaryotes?

In prokaryotes, transcription and translation occur simultaneously in the cytoplasm without compartmentalization.

What is the function of an activator in the regulation of operons in prokaryotes?

Activators are molecules that enhance transcription, often by binding to regulatory regions and facilitating RNA polymerase attachment.

What fundamental principle of molecular biology is described by the Central Dogma?

The Central Dogma states that genetic information flows from DNA to RNA (transcription) and then from RNA to protein (translation).

Describe the initiation step of translation.

mRNA binds to the ribosome, and the first tRNA carrying methionine attaches to the P-site, specifically matching the start codon AUG on the mRNA.