gene mutations

Question 1

mutation

Answer 1

• sudden change in the genetic makeup

- results as a change in the sequence of nucleotides

Question 2

What are mutagens?

Answer 2

• factors increasing the rate of mutations : environmental factors (ionising radiation, mutagenic chemicals and viruses and micro-organisms)

Question 3

How do mutagens affect organisms?

Answer 3

• variety of different effects
• somatic mutations, not transmitted to next generation, can cause cells to become malignant and subsequently cancer (plants - vegetative propagation such as budding)
• gametic mutations, occur in reproductive organs, germ-line mutations may lead to variation
• can lead to a new species to evolve, speciation, evolution

Question 4

neutral mutations

Answer 4

• do not affect the life line
• everyone has mutations, most not a phenotype
• some show in phenotype (tongue rollers and non-tongue rollers)

Question 5

beneficial mutations

Answer 5

• natural selection, nature selecting better adapted traits for an organism
• eventually speciation will occur
• most often occur in viruses and bacteria due to rapid reproduction (multi-resistent super-bugs)
• example, change from pale to dark moth to blend with dark ashy walls

Question 6

harmful mutations

Answer 6

• inheritance of mutations in single genes
• inherited as autosomal recessive traits
• heterozygous parents have one normal one mutated
• homozygous recessive parents have both gene copies that are non-functional

Question 7

albinism

Answer 7

• rare group of genetic disorders causing skin, hair, iris or eye to have little to no pigment
• mutation of one of several autosomal genes
• shows pattern of recessive monohybrid inheritance
• vulnerable to sun burn and cancer
• shunned, discriminated, work inside, mocked (prejudice, ignorance from wider community)
• genetic counselling, studying family tree
• not common in the wild, prominent in Africa, may be able to produce more Vitamin D

Question 8

single nucleotide polymorphisms

Answer 8

• STP occurs when a single nucleotide is substituted for another
• point mutations, evolutionary shown in significant amount of populations
• found in non-coding DNA, biological markers