Inheritance and disorders

Question 1

single gene disorders

Answer 1

disorders caused by inheritance of the defective gene and follow basic laws of heredity stated before.

Question 2

Dominant autosomal inheritance

Answer 2

Easily passed on as only one allele is needed for the trait to be seen, however dominant disorders that cause serious defects are rare because they die before they can reproduce. Relates to traits found of autosomal chromosomes

Question 3

Huntingsons (DA)

Answer 3

Involuntary flailing movements of arms and legs and has trouble voluntarily moving limbs. Withering movements and dementia. Controlled by a dominant allele. Not present until later in life so passed on without knowing

Question 4

REcessive, autosomal

Answer 4

A person who has heterozygous has a recessive allele but doesn’t show. (carrier). Only affected if homozygous recessive

Question 5

phenylketonuria

Answer 5

RA. controls the production of an enzyme called phenylalanine hydroxylase, which concerts aa phenylalanine to tyrosine. in no enzyme, phe builds up are becomes toxic damaging growing brain and maybe epilepsy. detected early, a special diet with no phe and substitutes

Question 6

cystic fibrosis

Answer 6

AR. chest infections, lack of digestive enzymes, and lots of NaCl loss. Detected in babies, if they have them low fat and high protein and carb with pancreatic extract and vitamins a d k .Sufferers of this disease produce a thick, sticky mucus which coats their airways and lungs. If it is not cleared daily the person can get serious chest infections.

Question 7

sickle cell anemia

Answer 7

AR. This inherited disease causes the red blood cells to change from their usual round shape to become pointed like a sickle.
Sickle cell disease is caused by a mutation in the haemoglobin-Beta gene found on chromosome 11
Causes the RBCs to become stiff and for a sickle shape.
It means that they get stuck in blood vessels and cannot pick up oxygen properly from the lungs.

Question 8

Sex chromosomes

Answer 8

Examination on 23rd pair of chromosomes in males shows that one pair is similar to femates but other is smaller

Question 9

Sex determination

Answer 9

All eggs produced by females contain an X chromosome while 50 50 female and male in men. As each sperm has an equal chance of reaching the egg, there is a 50/50 chance of of being male or female

Question 10

X- linked characteristics

Answer 10

Y chromosome is very small compared to x therefore y cannot have the same number of genes as x. Most genes on x will match alleles in y. But girls don’t have this problem,

Question 11

Colorblindness

Answer 11

Occurs when light-sensitive cells in theretinafail to respond appropriately to variations in wavelengths of light which allow us to see an array of colours.
Inherited forms- deficiencies in certain types of cones or outright absence of these cones (xr)

Question 12

hemophilia

Answer 12

Blood fails to clot, a mutation in a factor IIIV gene.
Sufferers are treated with the functional protein from GMOs.
The normal blood-clotting allele is dominant and is shown as XH. The recessive allele that causes Haemophilia is shown as Xh.

Question 13

pattern with x linked son and mum

Answer 13

(1) Sons x mus come from mum as he got y from dad so the father cannot pass a sex-linked trait to son. if mum has recessing gene they son will be affected

Question 14

dad and daughter

Answer 14

can only give x so is daughter has a recessive trait the dad must also have it

Question 15

CARRIERS

Answer 15

Exhibit the dominant trait (are unaffected) but carry the defective (recessive) allele and can pass the trait on to their children.
Sex-linked - Females are carriers, males always affected if they have one recessive allele.