Genetics final lesson before exam

• Biologie
• Middelbare school
• vwo
• Leerjaar 4

Repeat

Donderdag toets:

Phenotype and genotype

Phenotype = appearance  / Phenotype = genotype + environment

Genotype = genetic code (DNA) 

Body Cell (46)                    Sex cell (23)

Kitty is a long-haired female cat and has mated with Kobus. In her litter we find both long-haired kittens and short-haired kittens. The allele for long hair is recessive

Give the genotypes of both parents, show a punnett square of the cross and explain the expected phenotype ratio in the offspring. Complete this on paper, take a picture and upload here.

In cattle, the allele for a rough tongue is dominant over the allele for a smooth tongue. A cow is heterozygous for the gene. This cow has a calf with a bull that is also heterozygous for this gene.

What is the chance this calf is also heterozygous for this gene? Explain your answer by drawing a punnett square on paper, taking a picture and uploading that here.

In guinea pigs the allele for rough hair is dominant over smooth hair. A rough-haired heterozygous female has a litter. The offspring are all rough-haired. It is unknown who is the father. There are three options:
Male 1: smooth-haired
Male 2: rough-haired (homozygote)
Male 3: rough-haired (heterozygote)
Organise the males from most likely to be the father to least likely.

With newborn babies they extract a bit of blood to get tested. A child is tested and they find it has a metabolic abnormality called PKU. The child will have to follow a special diet. Neither of the parents shows symptoms of this disease. The parents would like to have another child. What is the chance their second child will also have PKU?

1. 12,5%
2. 25%
3. 50%
4. 100%

Is the gene for sickle cell anemia likely to be dominant or recessive? Explain your answer

The disorder shown on the pedigree is ​Maple Syrup Urine Disease​ (MSUD) which is a metabolic disorder that affects the body’s ability to process certain proteins.
1. What is the inheritance pattern of this gene?
a) dominant b) recessive
2. Provide at least one piece of evidence for your claim.

Charcot–Marie–Tooth disease​ (​CMT​)causes motor and sensory neuropathies of the peripheral nervous system.
1. What is the inheritance pattern shown?
2. ​ Provide at least one piece of evidence for your claim.
3. The dashed line represents a possible union. Discuss the probability that such a union would result in a child with CMT.

Cystic fibrosis​ is a disease that affects the ability of cells to move sodium across the cell membrane. This causes mucus to build up in the lungs resulting in respiratory problems.
1. What is the inheritance pattern shown?
2. ​ Provide at least one piece of evidence for your claim.