DNA is genetic material
DNA Replication
Transcription
Translation
Mutations
100
Name the purines.
Adenine and Guanine
100
DNA replication begins at _______________.
the orgins of replication
100
Where does transcription take place in a eukaryotic cell?
Nucleus
100
What is a codon?
Triplets of bases that code for proteins
100
What is a mutation?
The effects of changes to the genetic information of a cell (or virus)
200
Name the scientist(s) responsible for solving the puzzle of the DNA structure, who used X-ray crystallography to study protein structure.
Watson and Crick
200
What are helicases?
an enzyme that untwist the double helix at replication fork.
200
The DNA sequence that initiates transcription is known as the promoter. The crucial DNA sequence is _________.
TATA
200
Where does translation take place?
Cytoplasm/ @ Ribosome
200
What is a point mutation?
Chemical changes in a single base pair of a gene.
300
Which scientist studied two strains of bacteria in mice and found that living R bacteria had been transformed into pathogenic S bacteria?
Frederick Griffith
300
List two functions of DNA polymerase.
Catalyze the synthesis of new DNA Proofreads each nucleotide
300
List the stages of transcription.
Initiation, Elongation, Termination
300
What is the role of tRNA?
Picks up an amino acid in cytosol, deposits amino acid on polypeptide chain at ribsome, then leaves to pick up another amino acid.
300
What is the difference between missence and nonsense mutation?
Missence - substitutions that change one amino acid to another one. Nonsense - change a codon for an amino acid into a stop codon.
400
Explain the alternative models of DNA replication: Conservative, Semiconservative, and Dispersive.
Conservative - 2 parental strands reassociate after acting as templates for new strands Semiconservative - 2 parental strands seperate, and each act as a template for new complimentary strand Dispersive - each daughter strand contains mixture of old and new DNA
400
Take us thru the synthesis of the lagging strand starting with the role of primase and ending with DNA ligase.
Primase adds RNA primer. DNA pol. III adds DNA nucleotides to primer forming Okazaki fragments. DNA pol. I replaces RNA primer with DNA. DNA ligase forms bond between Okazaki fragments.
400
A polymerase initiates RNA synthesis. Which polymerase is used for this?
RNA polymerase II
400
List the 3 binding sites on the ribosome and in order.
A, P, E
400
What happens when one nucleotide pair is lost from the middle of a coding sequence of a gene?
In mRNA, the reading frame downstram from deletion is shifted, leading to a long string of incorrect amino acids in polypeptide, and in most cases, a stop codon will arise prematurely.
500
Explain Hershey and Chase experiment who asked the question, "Is protein or DNA the genetic material of phage T2?"
In batch 1, phages were grown with radioactive sulfur (protein), and showed that the phage proteins did not pass to the bacterial cells. In batch 2, phages were grown with radioactive phosphorous (DNA), and showed that the phage DNA entered bacterial cells. DNA, not protein, functions as the genetic material of phage T2.
500
Explain two ways how DNA replication is so accurate with little errors taking place.
Mismatch repair - enzymes remove and replace incorrectly paired nucleotides DNA pol. III - corrects base pairing Nucleotide excision repair - a nuclease enzyme cuts damaged DNA strand and removes. DNA polymerase repairs by filing in missing nucleotides.
500
Compare DNA polymerase and RNA polymerase in terms of how they function, the requirement for a template and primer, the direction of synthesis, and the type of nucleotides used.
Both assemble nucleic acid chains. Both synthesize in 5' to 3' direction. DNA pol. requires a primer, but RNA pol. can start a nucleotide from scratch. DNA pol. uses nucleotides with sugar deoxyribose and base T, whereas RNA pol. uses nucleotides with sugar ribose and the base U.
500
What 2 processes ensure that the correct amino acid is added to a growing polypeptide chain?
tRNA specifically recoginzes a single amino acid to attach. Second, a tRNAcharged with specific amino acid binds only to an mRNA codon for that amino acid.
500
Which of the following mutations would be most likely to have a harmful effect on an organism? a) a base-pair substitution b) a deletion of 3 nucleotides near the middle of a gene c) a single nucleotide deletion in the middle of an intron. d) a single nucleotide deletion near the end of the coding sequence e) a single nucleotide insertion downstream of, and close to, the start of the coding sequence.
E
M
e
n
u