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Higher Biology
Unit 1: DNA & the Genome
Unit 1.3 - Control of DNA Expression
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Cards (34)
What is gene expression?
Gene expression is the activation of
certain genes
in a cell to
produce particular proteins.
Only a
fraction
of the genes in a cell are
expressed.
RNA is made up of what?
A
single
strand of
nucleotides.
RNA nucleotides are made up of what?
A
phosphate
group, a
ribose
sugar and a
base.
What are the four types of RNA bases?
Adenine
,
uracil
,
guanine
,
cytosine.
What are the 3 types of RNA?
mRNA
,
tRNA
,
rRNA.
What does mRNA (messenger) do?
Carries a
copy
of the
DNA
code from the
nucleus
to the
ribosomes.
What does tRNA (transfer) do?
Found in the
cytoplasm
where it binds to
specific
amino
acids
and transports them to the
ribosome.
What does rRNA (ribosomal) do?
Forms a complex with
protein
molecules
to make the
ribosome.
What are the two stages of gene expression?
Transcription
and
translation.
Where does transcription take place?
In the
nucleus.
What enzyme breaks apart the hydrogen bonds and unwinds the double helix shape of DNA during transcription?
RNA polymerase
What does RNA do during transcription?
Synthesizes a
primary transcript
of
mRNA
from using
RNA nucleotides
by
complementary base pairing.
What does Uracil pair with?
Adenine.
What is a triplet of bases called?
Codon
What does a codon code for?
A
specific amino acid.
What are coding regions called?
Exons
What are non-coding regions called?
Introns
What does RNA splicing form?
A
mature mRNA transcript
What happens to the introns in a primary transcript?
They are
removed.
What happens to exons during RNA splicing?
Exons are
joined together
to form the
mature transcript.
What are ribosomes composed of?
Proteins
and
rRNA
Why does tRNA fold?
Complementary base pairing.
What does tRNA do in translation?
Carries
amino acids
to the
ribosome
What do tRNA molecules have on them?
An
anticodon
and an
amino acid attachment site.
What is each anticodon complementary to?
An
mRNA codon.
Where does translation begin?
At the
mRNA start codon
Where does translation end?
At a
stop codon.
What happens when the tRNA anticodon binds with a codon?
It translates the
genetic code
into a
sequence
of
amino acids.
What bonds join amino acids together?
Peptide bonds.
What is a chain of amino acids called?
A
polypeptide chain
What is alternative RNA splicing?
Process of removing
introns
and joining
exons
in
different
combinations to produce
multiple
mRNA transcripts from a single
gene.
Why do polypeptide chains fold?
To form the
three dimensional
shape of a
protein.
What is a phenotype?
Observable characteristic
of an
individual
What is an organism's phenotype determined by?
The
protein's
produced as the result of
gene expression
and also
environmental factors.