Lecture 8

Question 1

Where is the human LCT gene located?

Answer 1

2q21

Question 2

What does the human LCT gene do?

Answer 2

makes lactase (lactase breaks lactose into glucose and galactose)

Question 3

What type of TFs is human LCT gene regulated by? Where is the human LCT gene on? What type of gene expression is this?

Answer 3

positive TFs. On in intestine cells

this is an example of spatial gene expression: when a gene is on in only some cells. This is important in multicellular organisms

Question 4

Is LCT on in children or adults? What type of gene expression is this?

Answer 4

on in children, on in most adults

temporal gene expression: when a gene is on in only some developmental stages. Important in multicellular organisms

Question 5

What is homozygote? heterozygote? How do you write them as?

Answer 5

homozygote: a cell/organism with identical alleles of a gene of interest
A/A and a/a

heterozygote: a cell/organism with different alleles of a gene of interest
A/a

Question 6

What does it mean if a person has LCT persistence? LCT non-persistence?

Answer 6

LCT persistence: LCT remains active in adults, and can digest milk

LCT non-persistence: LCT turned off after weaning (age 8), lactose intolerance

Question 7

Is LCT persistence or non-persistence dominant?

Answer 7

LCT persistence

Question 8

Homologous chromosomes usually have the same (blank(s)) and often have different (blank(s)).

Answer 8

same length, centromere position, bands, genes

different alleles

Question 9

In heterozygotes, which allele is expressed?

Answer 9

dominant allele conceals the recessive allele

i.e. A-gene. A allele is dominant to the a allele

Question 10

How do you express an allele if you know the dominant phenotype of a cell/organism but don’t know if it is A/A or A/a

Answer 10

A/_