Genetic mutations

Question 1

Mutations

Answer 1

A mutation is any change in the genetic material of a cell

Mutations are important for several reasons:
- Mutations are the source of new variation important for evolution
- Mutations are important since they can lead to various human medical conditions including various types of cancer

Question 2

Causes of Genetic Mutations

Answer 2

Spontaneous mutations arise from inaccurate DNA replication

Induced mutations are caused by mutagens
- Chemical mutagens
- Radiation

Question 3

There are 2 main types of mutations

Answer 3

Mutations can happen on a number of different scales

1. Point Mutations involve only a single base pair in a DNA molecule
2. Chromosomal Mutations occur when sections of DNA are changed
   examples: Inversions, Gene Duplications, Translocation and Polyploidy

Question 4

Point Mutations the Details

Answer 4

Point mutations are caused by only ONE base pair that is
1. Substitution (causes silent, missense or nonsense mutations)
2. Insertion (causes frameshift mutations)
3. Deletion (causes frameshift mutations)

Question 5

Substitution

Answer 5

Silent: codes for same amino acid; nothing changes as the protien has the same amino acids in same sequence
Nonsense: premature STOP codon
Missense
- conservative: in the formation of the protein is the same (such as polar, non-polar, because they form tertiary structures)
(can have similar functions
we CONSERVE the function)
- non conservative: opposite

Question 6

Effects of Substitution Point Mutations

Answer 6

Silent mutations: change in bases but leads to no change in amino acids or exons

Missense mutation: change in the base sequence of DNA alters a codon, leading to a different amino acid being placed in the protein sequence

Nonsense mutation: change in the DNA sequence causes a stop codon to replace a codon specifying an amino acid

Question 7

Insertion or Deletion: Frameshift

Answer 7

Frameshift mutation: causes the reading frame of codons to change
- the ripple effects are much greater
ex. no stop codon

insertion: +1 frameshifted translation
deletion: -1 frameshifted translation

Question 8

Chromosomal Mutations

Answer 8

Translocation: movement of another chromosome/codon into another codon sequence
Inversion: Inverting the order of codons

Question 9

Somatic Cell and Germ (sex) Cell

Answer 9

Somatic cells are cells involved in growth, repair, and maintenance
Mutations can lead to cancer and may be involved in aging

Germ cells are found in the gametes
Mutations may appear in the offspring produced by sexual reproduction

Question 10

Cancer

Answer 10

These are six (6) main factors that Signify cancer cells:
Self-sufficiency in growth signals
Evading apoptosis
Sustained angiogenesis
Limitless potential for replication
Insensitivity to antigrowth signals
Tissue invasion and Metastasis