Chapter 10.2: From gene to protein Flashcards
transcription is the synthesis of
mRNA to DNA
with transcription a template…
strand of DNA is used
during transcription thymine in DNA is replaced with
uracil in RNA
mRNA directs the synthesis of
polypeptides
translation is the synthesis of
polypeptides
translation is carried out by
ribosomes
translation requires several types of
RNA
RNA is NOT a
protein
what are the purpose of ribosomes?
to translate RNA information
mRNA is…
instructions written by DNA to make a specific protein
rRNA is a structural RNA that
forms the functional subunits of ribosomes
tRNA are structural RNAs that…
recognize and carry amino acids to the growing peptide chain
who determined that the order of nucleotides in DNA encode for the amino acid order?
Francis Crick and Sydney Brenner
what is a codon?
a block of 3 DNA nucleotides corresponding to an amino acid
the genetic code….
specifies which amino acids will be used to build a protein
what is the start codon?
AUG
what is the purpose of stop codons?
to stop translation and release polypeptides
what are the 3 stop codons.
- UAA
- UAG
- UGA
initiation for transcription requires
multiple proteins
termination of transcription occurs at
specific DNA sequences
transcription factors + RNA polymerase leads to _______ and initiates ____ ______
- promoter
- initiates gene expression
what are the 3 mRNA modifications?
- addition of 5’ cap
- addition of 3’ cap
- removal of introns
what are introns?
non-coding sequences
what are exons?
sequences that will be translated
-critical info is stored
tRNAs carry
amino acids to the ribosome for addition to a growing polypeptide
ribosomes are made of a
small and large subunit
ribosomes bring together
specific tRNA anitcodons with mRNA codons
the subunits in ribosomes are made of
proteins and ribosomal RNA (rRNA)
what are the two functions of the ribosomes?
- decode the mRNA
2. form peptide bonds between amino acids
what are the three binding sites for tRNA in a ribosome?
- Anticodon site
- Polymerize site
- Exit site
what are the 3 stages of translation?
- initiation
- elongation
- termination
amino acids are added to the
c-terminus
ribosomes proceed along the mRNA in a
5’ -> 3’ direction
the release factor is a…
protein
how does the release factor introduce hydrolysis?
by adding a water molecule instead of an amino acid
hydrolysis of the polypeptide allows for
release of the polypeptide
what are point mutations?
substitution of a single nucleotide base
what is a silent mutation?
the same amino acid is inserted
during a missense mutation…
a change in the amino acid inserted
during a nonsense mutation…
the amino acid is changed to a stop codon
during a frameshift mutation…
an addition or deletion of a single base occurs
what disease is caused by frameshift mutations?
Huntington disease
