Mutations

Question 1

define mutation

Answer 1

• The random change in the mollecular structure of DNA during the replication of genes

Question 2

Types of mutation

Answer 2

• Qualitative change in the gene
• Changes in the order of genes on a chromosome
• Part of the chromosome is lost or duplicated

Question 3

how does mutation occur in body cells

Answer 3

• Somatic cells carrying the mutations, pass on the altered genetic instructions to their descendant, but they are not passed on to the next generation.
• Mutation is an evolutionary process and is natural

Question 4

Why are developmental psychologists interested in mutations and inherited disorders?

Answer 4

1. can disrupt the mechanisms of developement
2. the presence of inherited abnormalities can be detected early in development
3. Provide support for families of children to reduce negative effects

Question 5

Describe sickle cell anaemia

Answer 5

• This when both parents have this blood cell disorder
• Normal red blood cells are round in shape and cells take on a curved sickle shaoe
• The oxygen supply to the blood is reduced
• DANGER: Clot formation, blockage of small blood vessels
• Severe pain, heart enlargement, anaemia, premature death

Question 6

Describe albinism

Answer 6

• When the individual lacks melanin and possesses little to no pigment in the skin, hair and eyes.
• This can cause vision problems
• It is homozygous whereby its inherited from both parents

Question 7

Describe chromosomal abnormality

Answer 7

• This occurs when a child inherits too many or few chromosomes
• The main cause of chromosomal abnormalities is the age of the mother: as the mother ages, the ovum is more likely to suffer abnormalities due to longer term exposure to environmental factors.
• most of the zygotes fail to develop and are spontaneously aborted by the mothers body

Question 8

Describe sex-linked chromosomal abnormalities

Answer 8

• One chromosome of chromosome pair 23 is damages
• If the intact chromosome is Y (Y0), the fetus does not survive, without chromosome X, it cannot live.
• Fragile X syndrome is where the Y chromosome is intact and the X chromosome is impaired
• X0 girls: no breasts, pubic hair, infrequent mesntruation, infertile due to lack of estrogen production

Question 9

Describe XXY : klinefelter syndrome

Sex-linked chromosomes

Answer 9

• This is for boys
• This is when their development appears normal up until adolescence but they show no signs of maturation
• They exhibit low testosterone levels, infertile. The additional X chromosomes inhibits this development

Question 10

Describe Haemophilia

Answer 10

• This is common among males because they only 1 X chromosomes without an addictional X chromosme to counter the harmful gene
• Problems in blood clotting which can lead to internal and external bleeding

Question 11

Describe Phenylketonuria

Answer 11

• This is an inherited metabolic disorder that can lead to severe intellectual disability if left untreated
• This is a result of a lack of enzyme needed to break down certain proteins.
• This leads to build of phenylketonuria acid in the blood, which interferes with the normal development of brain cells

Question 12

State the common reasons for genetic counseling

Answer 12

1. Family history of a genetic condition
2. Membership in a certain ethinic group increases risk
3. Info regarding results of genetic testing, including blood tests, or ultra sounds
4. If parents are older, they have had several miscarriages, infertility or a medical condition