Midterm 2 - DNA Replication and Gene Expression Flashcards
1
Q
semi-conservative replication
A
- DNA synthesis
- two original strands of molecule separate
- each strand acts as a template for the synthesis of a new, complementary strand
2
Q
DNA polymerase III
A
- make more DNA
- primary enzyme complex
3
Q
DNA polymerase I
A
- make more DNA
- prokaryotes
- replication and repair
3
Q
primase
A
- enzyme
- synthesizes RNA primer
- new synthesis
4
Q
ribonucleotides
A
- building blocks of RNA
5
Q
deoxyribonucleotides
A
- nucleotide
- contains deoxyribose as its sugar
6
Q
origin of replication
A
- genome
- where replication is initiated
7
Q
replication fork
A
- Y-shaped structure
- formed during initiation of replication
8
Q
helicase
A
- during replication
- enzyme
- helps to open up the DNA helix by breaking the hydrogen bonds
9
Q
single-stranded DNA binding protein
A
- during replication
- protein that binds to the single-stranded DNA
- keeps two strands apart so that they can serve as templates
10
Q
template strand
A
- DNA strand
- specifies the complementary mRNA molecule
11
Q
RNA primer
A
- made by primase
- short stretch of nucleic acid
- complementary to the template
11
Q
DNA ligase
A
- repair DNA damage
- joining of breaks in backbone of duplex DNA
12
Q
leading strand
A
- synthesized continuously in the 5’-3’ direction
- in direction of replication fork
13
Q
lagging strand
A
- during replication
- replicated in short fragments and away from the replication fork
14
Q
okazaki fragments
A
- DNA fragment
- synthesized in short stretches on the lagging strand
15
Q
DNA polymerase I proofreading
A
- polymerase detects an incorrectly paired nucleotide
- removes and replaces nucleotide
15
Q
exonuclease activity
A
- act as proof-readers during DNA polymerization
16
Q
central dogma
A
- states that genes specify the sequence of mRNAs, which in turn specify the sequence of proteins
17
Q
codon
A
- 3 consecutive nucleotides in mRNA
- specify the insertion of an amino acid or the release of a polypeptide chain during translation
18
Q
transcription
A
- generation of new copy of DNA in cell
- converting DNA into messenger RNA
19
Q
non-template strand
A
- not used to transcribe mRNA
- identical to the mRNA except that T nucleotides in DNA are replaced by U nucleotides in mRNA
20
Q
promoter
A
- DNA sequence
- RNA polymerase and associated factors bind and initiate transcription
21
Q
TATA box
A
- conserved promoter sequence in eukaryotes and prokaryotes
- helps establish the initiation site for transcription
22
Q
transcription initiation complex
A
- determine whether gene is expressed
22
Q
termination of transcription
A
- final step of transcription
- required for preventing the inappropriate transcription of downstream genes
23
Q
pre-mRNA
A
- first form of RNA created through transcription in protein synthesis
- primary transcript of eukaryotic mRNA as it comes off the DNA template
24
Q
RNA processing
A
- processed before functional
25
Q
intron
A
- non-protein-coding intervening sequences
- spliced from mRNA during processing
26
Q
exon
A
- sequence present in protein-coding mRNA after completion of pre-mRNA splicing
26
Q
5’ cap
A
- specially altered nucleotide
- vital in creation of stable and mature messenger RNA
27
Q
poly-A tail
A
- modification added to 3’ end of pre-mRNAs
- to protect mRNA from the degradation and assist mRNA export from the nucleus
28
Q
polyadenylation signal
A
- sequence motif recognised by the RNA cleavage complex
29
Q
translation
A
- process of converting the genetic info from mRNA into a sequence of amino acids or proteins
30
Q
messenger RNA (mRNA)
A
- transfer info from DNA to the cell machinery that makes proteins
31
Q
transfer RNA (rRNA)
A
- temporary carriers of amino acids
32
Q
anticodon
A
- 3-nucleotide sequence in tRNA molecule
- corresponds to an mRNA codon
33
Q
aminoacyl-tRNA synthetases
A
- enzyme
- “charges” rRNA molecules by catalyzing a bond between the tRNA and a corresponding amino acid
34
Q
polypeptide elongation cycle
A
- amino acids brought to the ribosome by tRNAs and linked together to form a chain
35
Q
reading frame
A
- sequence of triplet codons in mRNA
- specify a particular protein
- a ribosome shift of one or two nucleotides in either direction abolishes synthesis of that protein
36
Q
STOP codon
A
- trinucleotide sequence within a messenger RNA molecule
- signals a halt to protein synthesis
