4:2 Gene Expression Flashcards
(27 cards)
What is a gene?
A unit of inheritance.
A specific sequence of nucleotides on DNA containing information for the formation of a functional product.
What is an allele?
An alternative sequence of DNA to a gene which may result in formation of a functional/non-functional product
What is transcription?
The process that makes an RNA copy of DNA
What is translation?
The process that uses information in the RNA to synthesize protiens
What is an example of how the nature of the genetic code is degenerate but specific?
Every codon codes for only one amino acid but some amino acids are specified by more than one codon
Example of how is genetic code triplet in nature?
UUU
UUA
UUC
Etc
State the three properties of the genetic code
- Triplet in nature
- Degenerate but specific
- Almost universal
Give an example of how the genetic code is nearly universal?
In mitochondria, chloroplasts and some some organisms, there are slight difference in stop codons
What is the relationship between the non template strand and the template strand?
They are complementary.
What is the relationship between the non-template strand and the mRNA strand?
They are similar
What is the relationship between the template strand and mRNA?
They are complementary (RNA pairing)
Describe transcription
- The DNA carrying the gene unwinds and unzips and the two DNA strands are separated.
- One of the DNA strands called the template strand is used to make the mRNA
What happens to the mRNA after transcription?
It leaves the nucleus through the nuclear pore.
It then attaches to a ribosome.
It then moves on to translation.
What is mRNA translation?
- The ribosome translates the message in mRNA into a sequence of amino acids joined together to form a polypeptide
As the ribosome moves along the mRNA, The polypeptide produced gets longer as more amino acids are joined together by peptide bonds.
At the end of the mRNA strand in the ribosomes detaches from the mRNA and the polypeptide is released.
What are the four types of genetic code Mutations?
Silent
Missense
Nonsense
Frameshift
What causes the silent mutation of a gene?
A change in the nucleotide sequence that does not change the amino acid specified by a codon
What is the effect of a silent mutation?
There is no change to the protein structure.
What is the cause of missense mutation in genes
It is a change in nucleotide sequence that changes the amino acid specified by codon
What is the effect of the missense mutation?
This results in a change in primary structure of protein which may be beneficial, neutral or deleterious
What causes the nonsense mutation in genes?
A change in the nucleotide sequence that results in a early stop codon
What is the effect of a nonsense mutation?
A shortened polypeptide, usually deleterious.
What is the cause of the frameshift mutation in genes?
A change in the reading frame of the nucleotide sequence. Caused by an addition or deletion of a nucleotide.
What is the effect of frameshift mutation?
This causes a drastic change in the sequence of amino acids after the point of mutation. This results in change in primary structure of protein and is almost always deleterious
What are chromosomes mutations due to?
- Deletions
- Duplications
- Inversions
- Translocations
