Structure
What nitrogenous base is found in RNA and not DNA?
uracil
What DNA segments are formed on the lagging (discontinuous) strand?
okazaki fragments
Which scientist found that DNA is the "transforming principle"
Avery
Which type of RNA carries the instructions from DNA to the ribosome?
mRNA
What would the effect of a silent mutation in a protein?
no amino acid change, protein functions normally
Adenine and Guanine belong to what category of nitrogenous bases?
purines
What enzyme is needed before DNA polymerase can attach?
DNA primase
What molecule did Hershey and Chase confirm did not carry genetic information?
proteins
What stage of transcription is when RNA nucleotides are added to the growing strand?
elongation
An insertion of one nucleotide occurs near the beginning of a gene. Which mutation is this an example of?
frameshift mutation
What is a nucleotide made up of in DNA?
phosphate group, deoxyribose sugar, nitrogenous base
What property of DNA means each new molecule has one original strand?
semiconservative
Why were viruses used in the Hershey and Chase experiment?
viruses: DNA & Protein, gives us 2 choices
What modification protects mRNA and helps ribosomes recognize it?
5' cap
Why is a frameshift mutation usually more severe than a point mutation?
Shifts reading frame, all downstream codons read incorrectly, likely nonfunctional protein
Why can't adenine bind with cytosine?
adenine: can only form two hydrogen bonds
cytosine: can form three hydrogen bonds
A mutation prevents an enzyme from connecting Okazaki fragments on the lagging strand. Which enzyme failed?
DNA ligase
What did Hershey and Chase label DNA and the protein coat with to determine whether DNA or proteins carried genetic information?
DNA: radioactive phosphorus
Protein coat: radioactive sulfur
If introns are not removed from pre-mRNA, how will the protein be affected?
protein will be misfolded or nonfunctional due to an incorrect amino acid sequence
A mutation deletes two nucleotides from a gene. Why does this almost always produce a nonfunctional protein?
deleting two nucleotides causes a frameshift = nonfunctional protein.
Explain why the two strands of DNA are described as antiparallel, and why this orientation is necessary for replication.
strands run in opposite directions so polymerase can synthesize new strands. Polymerase can only synthesize in the 5' to 3' direction
What are the key processes of the Central Dogma of Molecular Biology and what happens in each process?
Replication: DNA → DNA
Transcription: DNA → RNA
Translation: RNA → Proteins
If Griffith had injected mice with a mixture of heat-killed R strain and live R strain bacteria, what would happen to the mice, and why?
The mice would survive, because the r strain is non-virulent and cannot transform other bacteria
Why are Poly A tails important?
protects mRNA from degradation, helps it exit the nucleus, and assists ribosomes in recognizing and translating the mRNA efficiently
Why is a mutation in the start codon usually more severe than a mutation in the final codon?
A mutation in the start codon can prevent translation from beginning