Genetic Diversity Flashcards
What can genetic diversity be caused by?
-Gene Mutations
-Meiosis (independent segregation of homologous chromosomes and crossing over)
-Random fusion of gametes during fertilisation
-Chromosome mutations
What is a positive of genetic diversity?
Natural selection
What are examples of mutagenic agents?
X-rays, benzene, UV light
What are the several ways that the sequence of nucleotide bases in a gene can be altered?
Substitution, deletion, addition, duplication, inversion and translocation
What can mutations cause?
A different amino acid sequence in the encoded polypeptide
How does degeneracy affect mutations?
Due to degenerate nature of the generic code, not all mutations result in a change to encoded amino acids
What are examples of how the sequence of nucleotide bases in a gene can be altered?
-Substitution
-Deletion
-Addition
-Duplication
-Inversion
-Translocation
What could the substitution of a single base result in?
(6 things)
-Could get a stop codon causing protein synthesis to be prematurely terminated
-A new triplet coding got a different amino acid could result in a non-functional protein forming
-A different amino acid in the polypeptide chain changes but a functional protein is still produced
-Same amino acid could be coded due to degeneracy so the polypeptide chain remains unchanged
-Could cause disease
- Altering to the tertiary structure
How does substitution affect the tertiary structure of the polypeptide chain?
Different position of the bonding causes the protein to fold differently changing the shape of the protein
What does deletion result in?
(4 things)
-Every codon changes
-A frame shift
- The sequence of amino acids is altered from the point of mutation meaning the protein formed is almost always non-functional
- Tertiary structure changes as ionic, hydrogen and disulphide bonds are in different places
What does addition result on?
(3 things)
-A frame shift
-Sequence of amino acids is altered from the point of addition and the protein formed is non-functional
-Tertiary structure changes as ionic,hydrogen and disulphide bonds are in different places
What does duplication result in?
(3 things)
Same impact as addition
-Frame shift
-Sequence of amino acids is altered from the point of addition and the protein formed is non-functional
-Tertiary structure changes as ionic,hydrogen and disulphide bonds are in different places
What does inversion result in?
(6 things)
Same as substitution
- -Could get a stop codon causing protein synthesis to be prematurely terminated
-A new triplet coding got a different amino acid could result in a non-functional protein forming
-A different amino acid in the polypeptide chain changes but a functional protein is still produced
-Same amino acid could be coded due to degeneracy so the polypeptide chain remains unchanged
-Could cause disease
- Altering to the tertiary structure
What does translocation result in?
Same effect as deletion and addition combined
A base is deleted from one location and added at a separate section. Addition and deletion at the same time.
What causes alleles?
Mutations of a gene
How do alleles affect the polypeptide?
They differ in base sequence and code for different sequences of amino acids
This change can affect the position of hydrogen, ionic and disulphide bonds which changes the tertiary structure
How do mutations affect enzymes?
-The is changes to the tertiary structure due to the change in the amino acid sequence
-This affects where bonding occurs
-This affects how the protein folds
-This change to the tertiary structure may alter the shape of the active site and the enzyme is now non-functional as the substrate is no longer complementary
- Enzyme-substrate complexes are not formed
