DNA STRUCTURE
How many hydrogen bonds occur between Guanine and Cytosine?
Three hydrogen bonds
The enzyme that adds nucleotides to the newly synthesized DNA strand.
DNA Polymerase
Where does transcription occur in eukaryotic cells?
The nucleus
The structure where translation occurs
The ribosome
Mutation type that does not shift the reading frame.
What type of bond holds the backbone of DNA together?
Covalent bonds
This enzyme “unzips” DNA by breaking hydrogen bonds.
Helicase
What is the start codon for all DNA sequences?
MET - Methionine (AUG)
Molecules that bring amino acids to the ribosome.
tRNAs
If a mutation changes one codon into a STOP codon, predict the effect on the protein.
Translation will stop early, producing a shortened (likely nonfunctional) protein.
What three components make up a nucleotide?
Phosphate, sugar, nitrogenous base
The enzyme that seals fragments of DNA together during replication.
Ligase
The enzyme that synthesizes mRNA
RNA polymerase
A tRNA molecule has the anti-codon sequence CGA. What amino acid is it carrying?
Alanine --> The codon for Ala is GCU (which is complementary to the anticodon CGA)
Provide an example of a physical mutagen.
UV, x-ray, gamma rays
The backbone of DNA and RNA is composed of what alternating groups?
Sugar and phosphate groups
The model describing how replication results in one old strand and one new strand.
Semi-conservative replication
RNA polymerase binds to what sequence in order to initiate transcription.
The promoter
Translate the following mRNA sequence:
CGU AGU UAU
Arginine - Serine - Tyrosine
What type of mutation occurred here?
ORIGINAL: AUG GGG CGC AAU UAU UGC CGC
NEW: AUG GGG CGC AUA UUA UUG CCG
U insertion in the fourth codon, causing a frameshift
List three ways DNA differs from RNA.
Any of the following:
Double stranded
Contains deoxyribose
Nitrogenous bases: A, T, G, C
More stable
Function: Stores genetic information
Which strand of DNA do the Okazaki fragments form?
The lagging strand
The name of the sequence that ends transcription.
The terminator
A mutation has occurred in a gene that encodes ribosomal RNA. How might this affect translation in that cell?
Incorrect assembly of the ribosome resulting in reduced or incorrect protein synthesis
Why do insertion or deletion mutations often have a more severe effect than substitutions?
They can cause a frameshift, changing all downstream codons and drastically alter the protein.