Nucleic Acids

Helicase

Unzips DNA strands by breaking hydrogen bonds

SSBs

keep strands apart

Primase

adds short RNA primers to start synthesis

DNA Polymerase

adds nucleotides 5' to 3'

Leading strand

made continuously 5' to 3'

Lagging Strand

made discontinuously in Okazaki fragments 5' to 3'

RNASE

removes RNA primers

DNA Ligase

Joins fragments together with phosphodiester bonds

Topoisomerase

Relieves tension

Telomerase

Extends ends (telomeres)

RNA Polymerase

Binds to promoter region, Synthesizes RNA 5' to 3' using base pairing

Transcription factors

Help RNA Polymerase bind to promoter region

Capping

Adds modified G to 5' end, protection

Polyadenlyation

Adds poly-A tail to 3' end, stability

Splicing

Introns cut, Exons joined

Alternative splicing

Exons joined in different ways to make different combinations from one gene, allows for variety

Binds to start codon via…

Ribosomes via mRNA, initiator tRNA via anticodon pairing

tRNA molecules…

bring AAs to the ribosome

Aminoacyl tRNA synthetase

loads correct AAs on each tRNA

Ribozymes

Ribosomes that catalyze peptide bonds

Nucleotides have…

Phosphate group, 5 carbon sugar, nitrogenous base

Point mutation

Single base changes

Missense mutation

one amino acid changes

Silent

no change in amino acid

Nonsense mutation

changes amino acid to stop codon

Proofreading

DNA polymerase corrects mistakes during replication

Mismatch repair

fixes errors missed by proofreading, uses template strand

Homologous recombination

Uses a homologous template for accurate repair of double stranded breaks

Non homologous end joining

Ligates broken ends directly, more likely to cause mutations

Operon

Cluster of genes under one promoter and operator

Promoter

DNA segment where RNA Pol binds to initiate transcription

Operator

DNA segment that controls access of RNA Pol to genes

Regulatory Gene

codes for repressor protein that can bind to the operator

Repressor

protein that binds to the operator to block transcription

Inducer

Binds to repressor and inactivates it, allowing for transcription

Corepressor

Binds to repressor and activates it, turning off transcription

Negative Control

Transcription is inhibited by a repressor

Positive Control

Transcription is stimulated by an activator

Transcriptional Control

Nucleus, activators, repressors, chromatin remodeling

RNA Processing Control

Nucleus, splicing, capping, poly-A tail

RNA Transport and Localization Control

Nucleus to Cytoplasm, export control, mRNA localization

mRNA Degradation Control

Cytoplasm, deadenylation, decapping

Translational Control

Cytoplasm, initiation control, repressors

Protein Degradation Control

Cytoplasm, Ubiquitin to Proteasome

Protein Activity Control

Cytoplasm, phosphorylation, methylation, acetylation, modifications

DNA 2' carbon

H

RNA 2' Carbon

OH

Adenine

Guanine

Cytosine

Thymine

Uracil

How many H bonds does A-T have?

2

How many H bonds does G-C have?

3

DNA Primary Structure

Sequence of A T G C

DNA Secondary Structure

Two antiparallel strands in a double helix

DNA Tertiary Structure

Supercoiled around histone proteins

RNA Primary Structure

Sequence of A U G C

RNA Secondary Structure

Single stranded loop, double stranded stem

RNA Tertiary Structure

Folded 3D shapes

RNA Quaternary Structure

Multiple RNAs interacting

Protein Building Blocks

Amino Acids

Protein Mainchain Backbone

N-Ca-CO

Protein Sidechain

20 different amino acids

Protein Linkage (bond)

Peptide bonds

Protein Sequence Direction

N to C

Nucleic Acid Building Block

NTPs

Nucleic Acid Mainchain Backbone

Phosphate-Sugar

Nucleic Acid Sidechain

A G C T

Nucleic Acid Linkage (bond)

Phosphodiester bonds

Nucleic Acid Sequence Direction

5' to 3'