Gene Expression Flashcards
What is genotype
The genetic composition of a cell
What is genotype determined by
The sequence of DNA bases in its genes
What does the order of DNA bases determine
The sequence of amino acids that are joined together
What does the sequence of amino acids determine
The structure, shape and function of the protein produced
What is RNA
A single strand of RNA nucleotides
What do RNA nucleotides contain
Ribose sugar, a phosphate and a base (adenine, cytosine, guanine or uracil)
mRNA
Carries a copy of a section of the DNA code for a specific protein from the nucleus to the ribosome
rRNA
Ribosomal RNA proteins form the ribosome (where protein synthesis takes place)
tRNA
Carries a specific amino acid on its amino acid attachment site
Codons
Every three bases found on mRNA are grouped together
What are mRNA codons complementary to
The triplet of bases on the original DNA strand
Where is tRNA found
In the cytoplasm and is folded on itself due to hydrogen bonds forming between bases
What are anticodons
The triplet of bases left exposed on tRNA
What are tRNA anticodons complementary to
The mRNA codons
What is transcription
The copying of the DNA code for a specific protein into mRNA
Where does transcription occur
In the nucleus of a cell
What does RNA polymerase do
Unwind a specific section of DNA by breaking hydrogen bonds between bases
What is mRNA formed of
Free RNA nucleotides that pair with complimentary DNA bases (A–U, G–C)
What end does RNA polymerase add nucleotides
The 3’ end of mRNA
What is the primary transcript of mRNA
The mRNA that separates from the DNA template (before splicing)
Introns
Non-coding regions of genes
Exons
Coding regions of genes
What happens to introns during RNA splicing
Introns are cut out and removed from the primary transcript
When is the mature transcript of mRNA formed
When exons are spliced together to form a continuous sequence
Where does the mature transcript of mRNA move from
The nucleus, through the cytoplasm, to a ribosome
mRNA codon AUG
Acts as a start codon and codes for methionine (met)
mRNA codons UAA, UAG and UGA
Do not code for amino acids but they act as stop codons
Where does translation begin
At a start codon and ends at a stop codon
During translation where does the mature mRNA bind to
The ribosome
tRNA binds to its mRNA codon which lines up amino acids in a specific order
What do peptide bonds form between
Amino acids to form a polypeptide chain
How do polypeptide chains fold
By hydrogen bonding and other interactions to form the 3D shapes of proteins
