Mutations

Question 1

Mutation

Answer 1

Random changes in genome
-important for diversity
- happens all the time & randomly
- chromosomal or nucleotide lvl

Question 2

Somatic

Answer 2

A somatic cell is a cell in the body (except gametes)
-mutations in somatic cell only affects the individual.

Question 3

Point mutation

Answer 3

Changes in a single nucleotide of a gene (occurs during DNA replication) . Can result in substitution of 1 nucleotide. Sjuk massa misstag varje dag men majoriteten fixas av enzymer

Question 4

Insertion

Answer 4

2 non-homologous chromosomes accidentally get lined up and one section from ex chromosome 4 is inserted into nmr 20.

Question 5

Deletion

Answer 5

A section of a chromosome is missing - has been deleted by enzyme. (Can result in duplication)

Question 6

Duplication

Answer 6

A section of a chromosome is duplicated/ repeated. Can happen because homologous chromosomes are misaligned and cross over or cuz of deletion.

Question 7

Inversion

Answer 7

A section of the chromosome is cut and flipped upside down then placed back into the same chromosome.

Question 8

Translocation

Answer 8

Fragments of non-homologous chromosomes switch places. Fragment from a attaches to b and vice versa

Question 9

Substitution

Answer 9

When one single nucleotide is substituted for with another that affect 1 codon. Can lead to 3 outcomes: missense, nonsense & silent.

Question 10

Silent mutation

Answer 10

Occurs when mutated codon codes for the same amino acid as the original. (Many different combinations for same amino acid)

Question 11

Frameshift mutation

Answer 11

Insertions or deletions of single nucleotides that result in a shift in the reading frame of the sequence of bases.
* Orginal can be shifted +1 or -1 ➡️changes order of nucleotides ➡️ changes codons ➡️ unfunctional/ wrong protein.
* Can happen anywhere on a gene with different consequences

Question 12

Missense mutation

Answer 12

Occurs when the codon codes for a different amino acid than original. Severity depends on which new amino acid

Question 13

Nonsense mutation

Answer 13

Occurs when the mutated codon codes for termination ➡️ incomplete protein.

Question 14

Chromosomal abnormalities

Answer 14

Mutations in the structure of the chromosome. Occurs mostly during meiosis 1, fertilization; can occur mitosis.
Often lethal consequences in humans

Question 15

Structural chromosomal abnormalities

Answer 15

Difference in structure: deletion, duplication, inversion, insertion, translocation.

Question 16

Numerical chromosomal abnormalities

Answer 16

Changes in nmr of chromosomes, ex 45 or 47 (+/- 1). Often lethal due to cells being built to handle 2 chromosomes/ pair no more/less.
Ex down syndrome, Edward syndrome (trisome)