DNA replication test Flashcards
Pyrimadines
1 ring
cytosine and thymine
Purines
2 rings
Adenine and Guanine
How many hydrogen bonds between A and T?
2
How many hydrogen bonds between G and C?
3
Helicase
Unwinds parental double helix
Primase
synthesizes short RNA primer
DNA polymerase
links DNA nucleotides to growing daughter strand on 3’ end
ligase
links pieces together into a single DNA strand
Okazaki Fragments
lagging strand in DNA replication
rRNA
work bench of protein synthesis
mRNA
carries codon that determines the order of amino acids
tRNA
picks up specific amino acids and joins with codon of mRNA
Introns
noncoding portions of the newly transcribed mRNA
cap
reception of the nucleotide cap by the 5’ end of mRNA
exons
The actual coding portions of mRNA
tail
acquiring of a poly-A tail by the maturing mRNA transcript
mature mRNA transcript
presence of cap and tail, introns snipped out and exons spliced together
codon
individual base triplet in mRNA
The Genetic Code
How the nucleotide sequences of DNA and then mRNA correspond to the amino acid sequence
anticodon
A sequence of 3 nucleotide bases that can pair with a specific mRNA codon
Initiation of translation
attachment of RNA polymerase to the promoter and the start of RNA synthesis
Elongation of translation
RNA strand peels away from its DNA template allowing the 2 DNA strands to come together
Termination
RNA polymerase reacts a sequence of bases that signal the end of the gene
3 stages of a growing polypeptide chain
- Codon recognition
- Peptide bond formation
- Translocation
Codon recognition
The anticodon of an incoming tRNA molecule pairs with the mRNA codon while carrying its amino acid
Peptide Bond Formation
Polypeptide separates from tRNA and attaches by a peptide bond to the amino acid carried by the tRNA
Translocation
P site tRNA leaves the ribosome, while codon and anticodon stay bonded. mRNA and tRNA move as a unit
Mutation
Any change in the nucleotide sequence of DNA
base substitutions
replacement of one nucleotide with another
deletions and insertions
have disastrous effects on a sequence - alter the reading frame
Mutagen
a physical or chemical agent that sources mutation
Virus
a microscopic particle that consists of a nucleic acid enclosed in a protein coat
lytic cycle
results in the destruction of an infected cell
lysogenic cycle
viral dna replication occurs while destroying the host cell
reverse transcriptase
catalyzes the the synthesis of DNA on an RNA template
How many origins of replication and replication forks are shown ins the parental and daughter strand?
3 origins and 6 replication forks
Multiple origins of replication on the DNA molecules of eukaryotic cells serve to. . .
shorten the time necessary for DNA replication
Which enzyme catalyzes the elongation of a new DNA strand?
DNA polymerase
Why does DNA strand grow only in the 5’ to 3’ direction?
DNA polymerases can only add nucleotides to the 3’ end of the growing molecule
Monomers of DNA and RNA
nucleotides
When one DNA molecule is copied to make 2 DNA molecules, how much of the parent DNA remains?
50% of the parent DNA
