gene expression 1.3 Flashcards
genotype
the genetic material that an organelle possesses
phenotype
the physical appearance of an organism
what determines an organelles genotype
sequence of dna bases in its genes
what determines an organisms phenotype
the proteins that are produced as a result of expression
what determines the structure and function of a protein
the sequence of amino acids
messenger rna function
copies code from the dna molecule and carries it out to the ribosome where the proteins are synthesised
transfer rna function
attaches to a specific amino acid
transport amino acid to the ribosome
joins together with codon of mrna with anti codon of trna
ribosomal rna function
bound to structural proteins so form a ribosome. used in the synthesis of proteins.
what is a ribosome made of
rRNA and protein
what does rna polymerase do to the gene
unzips and unwinds the dna strands by breaking hydrogen bonds exposing a single template strand of DNA
how do free rna nucleotides bind to the dna strand
using base paring rules with weak hydrogen bonds between bases and strong covalent bond between phosphate of one nucleotide and the ribose sugar of the next
how is the addition of free rna nucleotides controlled
by rna polymerase
what direction ae free rna nucleotides added
only at the 3’ end in a 5’ to 3’ direction
when does the mrna stop copying the dna sequence
when a stop codon is reached
what happens once the stop codon is reached
the rna polymerase and mRNA strand are released
rna splicing
introns (non coding regions) are removed
exons (coding regions) are retained and joined together to form mature transcript of mRNA
(order of exons are unchanged)
where does the mature transpript go after splicing
out of a nuclear pore into the cytoplasm to attach to a ribosome
different mature mRNA transcripts are produced from the same transcript depending on what exons are retained
alternative RNA splicing
the site of protein synthesis
ribosome
translation summary
the synthesis of a protein molecule as a polypeptide under the direction of mRNA codons that code for a specific amino acid
what are the triplet of bases on tRNA called
anti-codon
trna has an attachment site for…..
a specific amino acid
where does the trna carry the specific amino acid
to the ribosome to be attached to the growing end of the poly peptide chain
each codon on the mRNA codes for
an amino acid
the tRNA molecule binds briefly tot he mrna codon and the amino acid is then….
added to the polypeptide chain being synthesised
amino acids are joined together by
peptide bonds (type of covalent bond)
poly peptide chains are joined together by
covalent bonds
proteins are made of
carbon, hydrogen, oxygen, nitrogen
primary structure of protein
initial amino acid sequence linked by strong peptide bonds to for a polypeptide chain
secondary structure of proteins
coiling and folding of the polypeptide chain due to hydrogen bonds
