Exam 1 Review Flashcards
DNA replication, transcription, translation, mutations, sense strands, anti-sense strands, mRNA, tRNA
- a) What is the base sequence of the DNA strand that would be complimentary to the following single-stranded DNA molecule? 5’-ATGTCGCGGGTTGACAATTTAACTGTCGCGCCGGGTTCACCGGATG -3’
3’- TACAGCGCCCAACTGTTAAATTGACAGCGCGGCCCAAGTGGCCTAC -5’
- b) Based on the sequence in the previous question, what would be the DNA base sequence and what amino acids would result? (use the amino acid chart)
Remember we are now using mRNA, making the sequence:
5’- AUG UCG CGG GUU GAC AAU UUA ACU GUC GCG CCG GGU UCA CCG GAU -3’
The amino acids would go as follows:
Met - Ser - Arg - Val - Asp - Asn - Leu - Thr - Val - Ala - Pro - Gly - Ser - Pro - Asp
The open reading frame is determined by the start codon (AUG in this case)
If the Sense Strand codon is 5’-[TAC]-3’ What is the:
- Anti-sense codon
- mRNA codon
- tRNA codon
- Amino Acid
(Given) Sense: 5’-TAC-3’
Anti: 3’-ATG-5’
mRNA: UAC
tRNA: AUG
Amino Acid: Tyr
If the mRNA codon is [CAA] What is the:
Sense codon
Anti-sense codon
tRNA codon
Amino Acid
This problem requires you to work forwards and backwards. Starting with mRNA, you can translate the Anti-sense to GTT, and the tRNA to GUU. From there you can translate the Sense from the anti-sense as CAA and the amino acid from the tRNA as Gln.
Overall:
Sense: CAA
Anti: GTT
(Given) mRNA: CAA
tRNA: GUU
Amino: Gln
T or F: A Mutation ALWAYS causes a mutant Phenotype
False
A messanger acid is 336 nucleotides long, including the initiator and terminator sequence. the number of amino acids in the proteins translated from this mRNA is:
a) 999
b) 630
c) 330
d) 111
e) 110
336/3=112
3 nucleotides per amino acid
112-1=111
(-1 because stop codon does not translate into amino acid)
Answer d) 111
A _____ mutation affects the phenotype only under certain conditions.
a) spontaneous
b) somatic
c) site-directed
d) conditional
d) conditional
Changing the codon ACC to AGA represents a ______ mutation.
a) missense
b) nonsense
c) frameshift
d) deletion
ACC = Thr
AGA =Ars
a) missense
A point mutation that changes a codon specifying an amino acid into a stop codon is called a:
a) missense mutation
b) nonsense mutation
c) frameshift mutation
d) deletion mutation
b) Nonsense Mutation
The enzyme that creates a short RNA oligonucleotide at initiation sites where replication is to be carried out os called:
a) Primase
b) DNA Ligase
c) DNA Gyrase
d) Exonuclease
a) Primase
T or F: Gram-negative bacteria have double cell membranes.
True
T or F: Nucleotides in each strand are linked by 5’-3’ phosphodiester bonds.
True
T or F: DNA synthesis on the lagging strand is continuous.
False (due to Okazaki Fragments)
T or F: Bacteria have one circular chromosome that is the main genome which carries housekeeping genes.
True
T or F: The lagging during DNA synthesis the Okasaki Fragments are being synthesized
True
T or F: The replication of the bacterial chromosome is unidirectional.
False
_______ relaxes the DNA strand
Topoisomerase
______ opens the strand and acts as a guide for primase on both strands.
Helicase
_______ keeps the DNA strand apart during replication process.
SSBP (Single Stranded BInding Protein)
_______ synthesize primer sequences that are used by DNA polymerase III.
Primase
_______ extends strands only in 5’-3’ direction, thus one strand is continuous and one is in short fragments (Okazaki Fragments)
DNA Polymerase
Replication continues until the replication fork enters a region of the chromosome called the ________.
Termination Region
T or F: Partitioning of the chromosome is the distribution of one daughter chromosome to each of the two daughter cells.
True
________ is able to pick up a specific amino acid and transfer it to ribosomes.
tRNA
_______ is synthesized complementary to a gene and subsequently translates into a polypeptide or protein at ribosomes
mRNA
T or F: The promoter is a neuleotide sequence located up-stream of the gene to which RNA polymerase binds at the initiation of transcription
True
_____ is where an aminoacyl-tRNA first attaches.
Site A/acceptor/aminoacyl site
______ is where the growing amino acid chain is temporarily being held by a tRNA as the next xodon in the mRNA is being read.
Site P/Peptide site
The peptide bond is formed by a ribozyme, called ______.
Peptidyl transferase
The 70s ribosome moves a distance of one codon down the mRNA through a process called ______.
Translocation
What breaks the covalent bond that holds the finished protein to the terminal tRNA
Site P/Peptide site
T or F: Sec YEG are proteins that assist the non-covalent folding/unfolding
True
A nucleic acid was analyzed and found to contain 32% A, 18% G, 17% C, and 33% U. The nucleic acid must be:
a) single stranded RNA
b) single stranded DNA
c) double stranded RNA
d) double stranded DNA
a) single stranded RNA
T or F: the Ter region is the area that contains multiple symmetrically arranged sites for trapping the replication fork.
True
Which mRNA codes for the following polypeptide?
Met - Arg - Ser - Leu - Glu
a) 3’-AUGCGUAGCUUGGAGUGA-5’
b) 3’-AGUGAGGUUCGAUGCGUA-5’
c) 5’-AUGCGUAGCUUGGAGUGG-3’
d) 1’-AUGCGUAGCUUGGAGUGA-3’
e) 3’- AUGCGUAGCUUGGAGUGA-1’
c) 5’-AUGCGUAGCUUGGAGUGG-3’
