Genetics

Question 1

what does the R allele in peas control

Answer 1

starch production. The gene codes for the starch branching enzyme

Question 2

what does the EGLN1 gene code for and why is it an advantage in snow leopards

Answer 2

high altitude

Question 3

How are the Cr allele and Cw allele related in snapdragon flowers

Answer 3

they’re semidominant. Both alleles are expressed to some extent

Question 4

in blood how are the A and B antigens described

Answer 4

codominant

Question 5

how many chromosomes are in drosophila

Answer 5

4. 2 autosomes and 2 sex chromosomes, either XX or XY

Question 6

how are males and females described in relation to gametes

Answer 6

Males= hetrogamatic (gametes either X or Y)
Females= homogamatic (gametes always X)

Question 7

in drosophila is eye colour autosomal or sex linked?

Answer 7

X linked

Question 8

why is there no independant assortment of the body colour and wing type in drosophila

Answer 8

because they are on the same chromosome and close together

Question 9

what is the pseudoautosomal region of the X and Y chromosome

Answer 9

part of chromosomes that are able to recombine during meiosis and allows them to act as homologous chromosomes

Question 10

Describe Kleinfelters Syndrome

Answer 10

male extra X chromosome
underdeveloped testis 
poor beard growth
XXY 
breast development

Question 11

Describe Turner Syndrome

Answer 11

Female 
X0
short stature
ovarian failure
restricted aorta
poor breast development
neck webbing

Question 12

what factor deficiency causes Haemophilia A and B and describe symptoms

Answer 12

A- factor VIII
B- factor IX
swollen joints 
low clotting factor 
risk of uncontrollable bleeding 
X linked recessive

Question 13

Describe colour blindness

Answer 13

X- linked recessive

Question 14

Describe Duchenne muscular dystrophy

Answer 14

loss of muscle function

X-linked recessive

Question 15

describe fabry disease

Answer 15

lysosome storage disorder
cataracts
skin lesions
liver and kidney disorders
X linked recessive

Question 16

describe fragile X mental retardation

Answer 16

mental retardation
X- linked dominant
facial features
large ears

Question 17

describe Lesch- Nyhan syndrome

Answer 17

severe learning difficulties
self mutilate
X linked recessive
excess uric acid
early death

Question 18

describe rett syndrome

Answer 18

X linked dominant
lethal in males
communication and physical disabilities

Question 19

Androgen Insensitivity disorder

Answer 19

46XY (female)
mutation in SRY gene
may have partial mutation
mix of male and female genetalia