c3 Flashcards
- What does the enzyme helicase do during DNA replication?
unwinds the double helix structure of DNA, separates to two single strands by breaking the hydrogen bonds between base pairs.
- what is a single stranded binding protein?
Binds to the DNA strands in order to keep them separated
- What does the enzyme primase do in DNA replication?
adds RNA primer to each strand, signaling where replication should start.
4.. What is the role of DNA polymerase in DNA replication?
Attaches to primer & adds new nucleotides to original strands
-Builds a new strand by pairing each base with its complementary base.
- leading strand is copied continuously.
-RNA primer is removed after
- What happens on the lagging strand during DNA replication?
ligase closes gaps creating a complete strand. At sugar phosphate bone
6.What is the end result of DNA replication?
2 identical double-stranded DNA molecules are produced, each with one original strand and one newly synthesized strand.
template strand
single strand of DNA used as a guide to make a new one.
Nucleotides
are the building blocks of DNA, made of A, G, C, and T.
direction DNA strands run in
anti parallel
what does DNA replication being semi-conservative mean
(one old strand, one new strand
RNA is temporary becuase
it needs to be replaced in the end with the final DNA structure
why is it important to replicate DNA
in order to fully duplicate cells properly, and to ensure each daughter cell receives a copy of the DNA.
where does DNA replication occur
nucleus of eukaryotic cells.
why is proofreading important
to prevent errors that could lead to incorrectly coded genes or proteins
lagging strand
DNA strand replicated in short fragments, joined by DNA ligase.
what organelle is responsible for protein synthesis
ribosome, , it reads the mRNA transcript and turns it into a protein.
what is transcription?
to make a mRNA strand from DNA
product of transcription
mRNA
3 types of RNA
Messenger RNA (mRNA)
Transfer RNA (TRNA)
Ribosomal RNA (rRNA)
mRNA transcript
piece of mRNA that will float out of the nucleus into the cytoplasm
template
DNA strand that serves as a guide for producing mRNA; determines the sequence of the mRNA.
exons
short sequences of the mRNA nucleotides used to make proteins
introns
Long sequences of the mRNA nucleotides that don’t code for anything (they interrupt coding)
spliceosome
removes introns before mRNA leaves and joins together exons
Poly A tail
to protect the mRNA strand from breaking down, as it also helps with translation initiation.
A codon
is a set of 3 nucleotides on the mRNA strand.
Anti-Codon
is a set of 3 nucleotides on the tRNA strand.
Initiation phase:
-RNA P binds to open the double helix
-recognizes promoter sequence and attaches to it before actual gene
Elongation phase
RNA P binds to mRNA strand using dna as template
-mRNA is complimentary to sense strand
Termination phase
-mRNA transcript floats out of nucleus & into cytoplasm
-RNA P detaches, helix reforms
-Ribosomes will read transcript and turn it into a protein
what is genetic engineering
take a desired trait from one organism and implant it into the genome of another organism
Recombinant DNA
creating a molecule of recombinant DNA. recombinant:
Within own species or
From another species (transgenic)
what is the Polymerase chain reaction (PCR)
to make copies of a specific dna sequence
gel electrophoresis
used to separate DNA in order to compare them,Smaller molecules move faster, larger ones move slower.
what is a mutation
changes in the sequence of dna
silent mutation
When the codon changes to something else with the same amino acid
missense mutation
Affects protein: can affect the function of protein, works less affective or not at all
non-sense mutation
stops codons
point mutation
Small changes in DNA that only affect one base pair
insertion mutation
nucleotides being added
nucleotides being removed
deletion mutation
nucleotides being removed
frameshift mutation
Insertion or deletion of DNA bases that changes the way the genetic code is read, leading to incorrect proteins.
translocation mutation
transfer of a large piece of DNA and putting it in a different spot in the genome.
inversion mutation
section of chromosome when inverts itself (usually not harmful)
causes of mutations
-Spontaneous mutations – mistakes made by DNA Polymerase III or I
-induced Mutations – caused by mutagens
Ex – UV light, X-rays, other radiation chemicals
DNA and RNA similarities
both have C,G,A, sugar, phosphate backbone
DNA compared to RNA
has thymine, 2 strands, deoxyribose sugar
RNA compared to DNA
has uracil, 1 strand, ribose sugar, temporary
restriction enzymes
cut DNA at specific sequences.
