proteinsynthesis Flashcards
define gene
base sequence of DNA that codes for the aminoacid sequence of a polypeptide or a functional RNA
define gene locus
the fixed position a gene occupies
define chromsome
one DNA molecule folded into a condensed form, wrapped around histone proteins in eukaryotes
what is an intron
DNA base sequences within genes which dont code for an amino acid sequence
what is an exon
DNA base sequences within genes that code for an amino acid sequence
what are non-coding multiple repeates
DNA base sequences betwen genes which do not code for an amino acid sequence
why is genetic code known as degenerate
more than one triplet can code for the same amino acid
why is genetic code known as non-overlapping
every triplet codes for one amino acid
why is genetic code described as universal
the same tiplets code for the same amino acids in all living organisms
what is the genome
the complete set of gene in a cell
what is the proteome
full range of proteins that a cell is able to produce
state the differences between a DNA nucleotide and an RNA nucleotide
- DNA nucleotides consist or a phosphate group, a deoxyribose sugar and a base whereas RNA nucleotides consist of a phosphate group, a ribose. sugar and a base
- instead of thymine on DNA, RNA has uracil
-DNA is a double helix, whereas RNA is only one polynucleotide strand
describe the structureof mRRNA
- single stranded polypeptide chain
describe th structure of tRNA
one polynucleotide chain with regions where it is double stranded giving it a clover leaf structure.
- has a binding site complimentary to a specific amino acid
- has a regio of 3 bases known as an anticodon.
what is a triplet
3 DNA bases whihc ocde for a specific amino acid
what is a codon
a sequence of three bases on mRNA molecule which code for a specific amino acid
what is an anticodon
a sequence of 3 bases on a tRNA molecule which code for a specific amino acid
what is splicing
process by which introns are removd from the mRNA strand.
describe the process of transcription
- an ezyme attaches to and unwinds DNA double heliix at site to be transcribed
- hydrogen bonds between the two strands are broken, DNA strands separate
- one strand is used as a template
- free RNA nucleotides join to the exposed DNA bases and bind via complimentary base pairing: adenine to thymine, cystosin to guanine.
- the ezyme RNA polymerase joiins free RNA nucleotides toogether forming phosphodiester bonds which form pre-mRNA ehich contain intrns and exons.
- introns are removed by splicing
- exons are joined together tp produce an RNA molecules that coes for the protein or functional RNA
describe the process of translation
-mRNA attatches to ribosome
- 2 codons fit into the ribsome at one time
- tRNA carrying a specific amino acid binds to the first codon on mRNA via complimentary base pairing
- a second tRNA strand carrying a specific amino acid binds to second codon on mRNA starnd via complimentary base pairing with its anticodon.
- enzymes join aminoacids together forming pepptide bonds using energy from hydrolysis of ATP
- ribosome moves onto netx codon
- tRN is removed fom first codon and collects another of the same amino acid.
- anoher tRNA carrying a specific amino acid binds to the 3rd codon on mRNA via complimentary base ppairing with its anticodon and a new peptie bond is formed
- this process repeats until a stop codon is reaached
- polyypeptide detaches from the ribosome.
describe the differences in DNA between prokaryotic/ chloroplast/ mitochondria DNA and Eukaryotic DNA
prokaryotic, chloroplast and mitochondria DNA:
- circular
- shorter than eukaryotic
- not associated with histone proteins
- does not form chromosomes
-does not contain no-coding DNA
eukaryotic DNA:
- linear DNA
- associated with histone proteins
- forms chromosomes
- contains introns and no-coding multiple repeats
