Gene expression Flashcards
(28 cards)
Genes are encoded
into DNA and the genetic code is found in all forms of life
human genes
have introns (non coding) exons (coding)
gene expression is when
genes are transcribed and translated during
genes in a cell
only a fraction of the genes in a cell are expressed
gene expression is controlled
by the regulation of transcription and translation
gene expression is influenced
by intracellular and extracellular environmental factors
genes produce
proteins
gene expression results in
the phenotype of an individual human
protein have a variety
of structures
molecular shapes
which allows a wide range of functions
polypeptides
proteins make polypeptides
chain amino acids held together by peptide bonds and folded in various ways
gene expression involves
three types of RNA
RNA
single stranded
its nucleotides contain ribose instead of deoxyribose
the base uracil (U) replaces the thymine(T) found in DNA.
DNA in the nucleus
in transcribed to produce messenger RNA (mRNA), which carries a copy of the genetic code
RNA polymerase
moves along DNA, unwinding the double helix and aligning RNA nucleotides by complementary base pairing to a primary transcript
introns are removed from the primary transcription and the exons spliced to form
a mature mRNA transcription
alternative RNA splicing allows
different mRNAs to be formed from the same primary transcription depending on which RNA segments are treated as exons and intons
codons
triplets of bases on mRNA
products of translation of mRNA
polypeptides
codons code for a
amino acid
stop and start condons
Ribosomes are made from
ribosomal RNA (rRNA)
mRNA carries a
copy of DNA code from the nucleus to ribosomes
Transfer RNA (tRNA) folds becauase
base pairings and forms a triplet anticodon site an attachment site for specific amino acid
amino acid are carried
by specific tRNA molecules
tRNA anticondons
align to their complementary codons on mRNA