unit 1.3: gene expression Flashcards
what is genotype determined by
sequence of DNA bases in its genes
what is phenotype determined by
proteins produced as a result of gene expression
what is gene expression
the activation of a gene that results in the formation of a protein
what is gene expression influenced by
intra-cellular
extra-cellular
environmental factors
what is the second type of nucleic acid
RNA
what does RNA stand for
ribonucleic acid
what sugar does RNA have
ribose
what is the difference between RNA and DNA
RNA:
single stranded
ribose sugar
A, U, G, C bases
DNA:
double stranded
deoxyribose sugar
A, T, G, C bases
what are the 3 types of RNA
messenger RNA (mRNA)
transfer RNA (tRNA)
ribosomal RNA (rRNA)
where is mRNA formed
the nucleus
what does rRNA combine with to form
combines with proteins to form the ribosome
what does tRNA do
carries a specific amino acid to the ribosome to build proteins
what is the process of transcription
RNA polymerase moves along DNA unwinding and breaking hydrogen bonds
RNA polymerase adds nucleotides onto 3’ end of growing mRNA molecule
due to base pairing rules mRNA will be complementary to DNA
produced is the primary transcript
what process occurs after transcription
RNA splicing
what are coding regions
exons
what are the non coding regions
introns
what is the process of RNA splicing
primary transcript (mRNA), introns are removed and exons spliced together to form a continuous sequence, during splicing exon order remains unchanged, this forms the mature transcript, which leaves the nucleus and travels to the cytoplasm
what characteristics does tRNA have
anti-codon binding site
amino acid attachment site
folds due to complimentary base pairing
what is the process of translation
tRNA attaches to mRNA mature transcript at the ribosome and reads from 5’end to 3’end the sequence
a start codon is placed
tRNA anti-codon aligns with codon on mRNA
a specific tRNA molecule then carries the specific amino acid based on the codon found on mRNA
this is added to the growing chain of amino acids
process continues until all codons have been read and stop codon is placed
peptide bonds form between the amino acids and a polypeptide (protein) is formed
what is the structure of the ribosome
small roughly spherical
contain enzymes for protein synthesis
large subunit:
exit tunnel
E site - exit site
P site - peptidyl tRNA binding site
A site - aminoacyl tRNA binding site
small subunit:
mRNA binding site
how can several proteins be produced from one gene
alternative RNA splicing
what is the process of alternative RNA splicing
some exons (coding regions) excluded from the final mature transcript, introns may be retained
what are the main distinct groups of protein structure
fibrous proteins
globular proteins
conjugated proteins
what are the examples of fibrous proteins
keratin
elastin
collagen
actin
myosin
