MOLBIO LAB 3

A series of nucleotides or polynucleotides

Nucleic Acid

It comprises of a nitrogenous base and a 5-carbon sugar (pentose)

Nucleoside

Nitrogenous base + 5-carbon sugar (pentose) + phosphate residue

Nucleotide

What bond links nucleotides together in nucleic acids?

phosphodiester bonds

Purine bases

Adenine; Guanine

Pyrimidines bases

Cytosine; Thymine; Uracil

The bond between the base pairs in a DNA structure

Hydrogen Bonds

Requirements for proper hydrogen bonding

Strands must be antiparallel; Strands must be complementary

This describes DNA as a right-handed double helix consisting of two antiparallel strands held together by hydrogen bonds between complementary base pairs

Watson-Crick model

This rule states that the amount of Adenine is equal to the amount of Thymine and that the amount of Guanine is equal to the amount of Cytosine.

Chargaff's Rule

At what pH range does all dsDNA molecules retain the same shape and size?

pH range of 4-9

What happens when it is outside the pH range?

Hydrogen bonds may be disrupted; Helix can unwind

The central dogma describes the flow of genetic information:

DNA → RNA → Protein

It exists as a single-stranded polymer

Ribonucleic Acid (RNA)

What protein helps package DNA in the nucleus?

Histone

What is the basic unit of chromatin?

Nucleosome

What form of chromatin is loosely packed and transcriptionally active?

Euchromatin

What form of chromatin is tightly packed and inactive?

Heterochromatin

What process copies DNA before cell division?

Replication

What enzyme unwinds the DNA double helix?

Helicase

What enzyme relieves DNA supercoiling during replication?

Topoisomerase

In what direction does DNA polymerase synthesize DNA?

5′ to 3' direction

What strand is synthesized continuously during replication?

Leading

What strand is synthesized discontinuously?

Lagging

What short fragments are formed on the lagging strand?

Okazaki

What enzyme joins Okazaki fragments together?

Ligase

What process produces RNA from DNA?

Transcription

What region of DNA does RNA polymerase bind to start transcription?

Promoter

What process converts RNA into DNA?

Reverse transcription

What enzyme performs reverse transcription?

Reverse transcriptase

What process produces proteins from mRNA?

Translation

What structure is the site of protein synthesis?

Ribosome

What type of mutation does not change the amino acid?

Silent Mutation

What mutation changes one amino acid to another?

Missense mutation

What mutation creates a premature stop codon?

Nonsense mutation

What mutation shifts the reading frame?

Frameshift

What RNA carries genetic information to the ribosome?

mRNA

What RNA carries amino acids to the ribosome?

tRNA

What RNA forms the ribosome structure?

rRNA

This end must be methylated to form a cap

5' end

This end must have several adenine bases added to form a Poly-A Tail

3' end

Start codon

AUG

What amino acid does AUG specify?

Methionine