molecular genetics unit 6

Where is DNA located in eukaryotes vs. prokaryotes?

Eukaryotes: in the nucleus; Prokaryotes: in the nucleoid region (no membrane)

What is the central dogma of molecular biology?

DNA → RNA → Protein

What does Chargaff’s Rule state?

A = T and G = C

What are the types of RNA and their functions?

mRNA: codes for proteins, tRNA: brings amino acids, rRNA: part of ribosome, miRNA: gene regulation

What is the sugar difference between DNA and RNA?

DNA: deoxyribose, RNA: ribose

Which nitrogenous base is in RNA but not DNA?

Uracil (RNA); Thymine (DNA)

What is meant by DNA’s antiparallel structure?

One strand runs 5'→3', the other 3'→5'

What is DNA replication described as?

Semi-conservative (one old strand, one new strand)

What enzymes are involved in DNA replication?

Helicase, DNA polymerase, Primase, Ligase, Topoisomerase

What are Okazaki fragments?

Short DNA fragments on the lagging strand

What are the steps of transcription?

Initiation, Elongation, Termination

What is transcription?

Copying DNA into RNA

What is translation?

Decoding mRNA to build proteins

What are codons and anticodons?

Codons: mRNA triplets; Anticodons: tRNA triplets

What are the steps of translation?

Initiation, Elongation, Termination

What is an operon?

A group of prokaryotic genes regulated together

What do repressors and activators do in operons?

Repressors inhibit transcription; Activators promote transcription

What is the lac operon and how is it regulated?

Metabolizes lactose; turned on by allolactose (inducer)

What is the trp operon and how is it regulated?

Produces tryptophan; turned off by tryptophan (corepressor)

How is gene expression regulated in eukaryotes?

Chromatin access, transcription factors, RNA processing, translation, protein activity

What is PCR used for?

To amplify DNA sequences

What does gel electrophoresis do?

Separates DNA fragments by size

What is DNA sequencing?

Determines the order of nucleotide bases