Protein Synthesis Flashcards
What is a gene?
a section of DNA that codes for a protein
How does a gene code for a protein?
made out of a sequence of bases
each 3 bases code for 1 amino acid
a sequence of bases codes for a
sequence of amino acids
this determines primary structure
What are the properties of a triplet code?
it is degenerate most amino acids are codes for by more than 1 triplet
it is non overlapping
it is universal
What are exons and introns?
introns are non coding dna
exons are coding dna (EXpressed)
what is the difference between prokaryotic DNA and eukaryotic DNA?
prokaryotic cell - DNA is shorter and are not associated with proteins, circular
eukaryotic cell- DNA is longer, linear and associated with proteins
How does DNA coil?
8 histones attach to a DNA molecule
and form a nucleosome
multiple nucleosomes stack together to form a solenoid fiber
The fiber is then coiled again using scaffolding proteins and becomes chromatin
this condenses more and becomes chromosomes
What are homologous chromosomes?
when one chromosome is maternal and one is paternal
What is an allele?
different forms of the same gene
what is the central dogma of molecular biology?
DNA -> transcription -> RNA -> translation -> protein
Describe how transcription works
RNA polymerase attaches to a DNA sequence
the H bonds break exposing the bases
one of the strands is used like a template
free nucleotides are attracted to their complementary base pair
RNA polymerase joins them together to make mRNA
the RNA polymerase pulls off when it reaches a stop signal
then the mRNA exits via a nuclear pore
Describe the process of translation
the mRNA goes through the ribosome and the ribosome reads the mRNA one triplet code at a time
the ribosome attaches at the start codon AUG and the tRNA molecule then moves on with a complementary anticodon sequence UAC and pairs with the codon.the tRNA has a specific amino acid on the other side.
the mRNA then moves on and another triplet code is read, and another tRNA molecule attaches
the two amino acids are joined by a peptide bond.
What is DNA splicing?
splicing is the process of removing introns via spliceosomes
How does a mutation lead to a non functional enzyme?
the base sequence changes sequence of amino acids changes primary structure changes tertiary structure changes active site changes substrate no longer complementary no longer form ES complexes
What types of mutation are there?
Substitution- one of the bases gets substituted for another one
Deletion- one of the bases gets deleted, amino acids are read differently
