3.4 - Genes and Environment

Question 1

What two things cause a difference in phenotype?

Answer 1

• Genetic makeup (genotype)

- The environment in which an individual develops`

Question 2

What is monohybrid inheritance?

Answer 2

Each allele codes for one characteristic, and each characteristic is controlled by only one allele

Question 3

What is polygenic inheritance?

Answer 3

The characteristic is controlled by alleles at several different loci

Question 4

What is a multifactorial condition?

Answer 4

The condition is caused by genes at multiple loci, as well as environmental factors

Question 5

What is the pigment that makes hair and skin darker?

Answer 5

Melanin

Question 6

What cells is melanin made in?

Answer 6

Melancyotes

Question 7

What hormone stimulates melanin production?

Answer 7

Melancyote-stimulating hormone (MSH)

Question 8

What organelles do melancyotes place melanin into?

Answer 8

Melanosomes

Question 9

How does melanin make skin darker?

Answer 9

Melanosomes are transferred to nearby skin and hair cells, where they collect around the nucleus, protecting the DNA from UV light

Question 10

How does UV light darken the skin?

Answer 10

It increases the amount of MSH and MSH receptors,