Mutation

Question 1

Mutation

Answer 1

Alteration in the genetic make up or DNA sequence, resulting in the change of the phenotype or genotype of an organism is termed as Mutation

Question 2

Types of mutation

Answer 2

Spontaneous mutation
Induced mutation

Question 3

Spontaneous mutation

Answer 3

❑ Occurs spontaneously in nature
❑ Frequency of occurrence is very low
❑ It occurs as a part of evolution
❑ It is produced due to naturally occurring components in nature (UV rays, electric
currents etc.)

Question 4

Induced mutation

Answer 4

❑It is induced artificially
❑It occurs comparatively at a higher frequency
❑It is produced by chemical mutagens (mutation causing chemicals) , Gamma rays, X-rays etc…)

Question 5

base substitution mutation example

Answer 5

1. Sickle cell anaemia is an example of base
   substitution mutation.
   2.Glutamic acid (GAG) —> Valine (GUG).
2. This results in the Haemoglobin molecule of
   the RBC to distort and appear sickle shaped

Question 6

Transitions

Answer 6

Transitions are base pair replacement mutations where a
purine is replaced by another purine, or a pyrimidine is
replaced by another pyrimidine.
AT can be replaced by GC and GC can be replaced by AT.

Question 7

Transversions

Answer 7

Transversions are base pair replacement mutations where
a purine is replaced by a pyrimidine and a pyrimidine is
replaced by a purine.
CG can be replaced by GC and TA can be replaced by AT

Question 8

Chromosomal abberation: types

Answer 8

Euploidy
Aneulodploidy

Question 9

Euploidy

Answer 9

It is the change in the entire set or genome. The entire set of chromosome is either added or deleted.

Question 10

Aneuloploidy

Answer 10

when only one or two individual chromosome is added or deleted
❖ Trisomy (2n + 1) – Down’s Syndrome (Autosomal Trisomy)
- Klinefelter’s Syndrome ( Trisomy of sex chromosome)
❖ Monosomy (2n – 1) – Turner’s syndrome (One X chromosome is missing in female)

Question 11

Down syndrome: genetically

Answer 11

❑ Autosomal chromosome abnormality
❑ Trisomy in the 21st chromosome (Triplo-21)
❑ 47 chromosomes in total.

Question 12

Down syndrom appearance

Answer 12

❑ Short stocky body
❑ Varied degree of mental retardation
❑ Characteristic eye folds
❑ Lack of muscle tone

Question 13

Turner syndrome

Answer 13

• Monosomy of sex chromosome (only one X chromosome is present)
• Short stature
• Lack of ovarian development
• Neck abnormalities
• Skeletal disorder

Question 14

Klinefelter syndrome

Answer 14

• Trisomy of sex chromosome- XXY (an additional X chromosome in males)
• Sexually underdeveloped
• Infertility
• Sparse facial and body hair
• Developmental delays