DNA, RNA and Proteinsynthesis (Topic 4A) Flashcards
name the type of bond between complementary base pairs in DNA
hydrogen bonds
name the type of bond between adjacent nucleotides in a DNA strand
phosphodiester bonds
what shape is tRNA?
clover leaf shape
what shape is mRNA?
linear
does tRNA have hydrogen bonds?
yes
does mRNA have hydrogen bonds
no
does tRNA have an amino acid binding site?
yes
does mRNA have an amino acid binding site?
no
does tRNA or mRNA have an anticodon?
tRNA
(mRNA has an codon)
describe and explain the difference in the structure of mRNA and pre-mRNA
mRNA has fewer nucleotides because of its splicing
name the fixed position of a gene on a DNA molecule
locus
describe how a gene is a code for the production of a polypeptide (3 marks)
- because base sequence
- in triplets
- determine order of ammo acids in a polypeptide
how is DNA stored in eukaryotic cells?
in chromosomes found in the nucleus
how is DNA stored in prokaryotic cells?
in supercoiled chromosome
a gene is…
a sequence of DNA bases that codes for a single polypeptide
each amino acid is coded for by…
a sequence of three bases, called a triplet or codon
the proteome is…
the full range of proteins a cell is able to produce
introns are…
sections of DNA that don’t code for amino acids
do introns affect the amino acid order?
no
when are introns removed in eukaryotes?
proteinsynthesis
all the bits of DNA that do code for amino acids are called…
exons
an allele is…
all the different versions of the same gene
alleles for the same characteristic can be found at the same fixed position on each chromosome which is called..
the locus
proteinsynthesis is…
the production of proteins from the information contained in a cell’s DNA
the 3 main stages of proteinsynthesis are….
transcription
splicing
translation
transcription is when…
the DNA code is copied into mRNA
translation is when…
the mRNA joins with a ribosome and the code it carries is used to synthesise a protein
mRNA is a _____ polynucleotide strand
single
when is mRNA made?
during transcription
what does mRNA do?
carries the genetic code from the DNA to the ribosomes for translation
what does tRNA do?
carries the amino acids that are used to make proteins to the ribosomes in translation
the 4 steps of transcription are…
- RNA polymerase attaches to the DNA
- complimentary mRNA is formed
- RNA polymerase moves down the DNA strand
- RNA polymerase reaches a stop signal
after transcription what process occurs?
splicing
what happens in splicing?
introns from pre-mRNA are removed and exons are joined together forming mRNA strands.
where does translation occur?
in the cytoplasm on ribosomes
what molecule is needed for translation to work?
a tRNA carrying an amino acid
the 7 steps of translation are…
- mRNA attaches to ribosome
- tRNA anticodon binds to mRNA codon
- tRNA brings specific amino acid
- amino acids join via peptide bonds
- tRNA released
- ribosome moves along the mRNA producing polypeptide
- pre-mRNA is spliced to form mRNA
the genetic code is…
the sequence of base triplets in mRNA which code for specific amino acids
the genetic code is non-overlapping which means…
base triplets don’t share their bases
the genetic code is degenerate this means…
there are more possible combinations of triplets than there are amino acids
the genetic code is universal this means..
the same specific base triplets code for the same amino acid in all living things
