Lecture 18: Genetics

Question 1

How many copies of genes do we inherit? And from whom?

Answer 1

2 copies, from you biological mother and father.

Question 2

What does the study of genetics entail?

Answer 2

Inheritance

Question 3

What does the study genetics consider?

Answer 3

phenotype and genotype

Question 4

What are different versions of a gene called?

Answer 4

Alleles

Question 5

What are the different types of genotype?

Answer 5

Homozygous and heterozygous

Question 6

Define homozygous and heterozygous.

Answer 6

• Homozygous: both copies are the same

- Heterozygous: both copies are different

Question 7

What can cause complications with gene expression?

Answer 7

The production of a protein by an allele that overpowers the other allele.

Question 8

What is the name of an allele that can overpower another allele?

Answer 8

The dominant allele.

Question 9

What is the name of an allele that can be overpowered by another allele?

Answer 9

The recessive allele.

Question 10

How can one study inheritance easily?

Answer 10

Over many generations of a species.

Question 11

What are organisms called that are typically homozygous?

Answer 11

True breeding organisms

Question 12

What must a heterozygote always have?

Answer 12

A dominant phenotype.

Question 13

How many alleles do humans have? Explain why?

Answer 13

-two alleles, because they are diploid.

Question 14

Explain the type of genotype that someone with Rr has.

Answer 14

-A heterozygous genotype

Question 15

Explain the type of genotype that someone with RR has

Answer 15

-A dominant homozygous

Question 16

Explain the type of genotype that someone with rr has

Answer 16

-A recessive homozygous

Question 17

What is used to make predictions?

Answer 17

The Punnett Squares.

Question 18

Describe how Punnet squares are used?

Answer 18

• Indicate which each parent can produce
• Create all possible combinations of offspring
• Predict the probability that two parents have a certain type of offspring.

Question 19

Define test cross.

Answer 19

A test cross involves breeding and unknown specimen with a recessive individual. And the ratio of offspring tells you the unknown genotype of the other parent.

Question 20

What genotype carries a recessive disease?

Answer 20

The heterozygous genotype that carries the disease

Question 21

What genotype has a recessive disease?

Answer 21

The recessive homozygous genotype that has the disease.

Question 22

What type of disease is cystic fibrosis?

Answer 22

A recessive disease.

Question 23

If two parents have a recessive disease, what % chance will the child have this disease as well?

Answer 23

100%

Question 24

Can cystic fibrosis can be verified with genetics? if so, when?

Answer 24

Yes, at a fetal stage.

Question 25

How fraction of people carry the cystic fibrosis recessive disease?

Answer 25

1/25

Question 26

How can genetic diseases be sexist?

Answer 26

since women have two X chromosomes and men only have one X chromosomes, any recessive disease carried through the X chromosomes will be expressed in the male phenotype. For a girl to inherit a recessive disease on the X chromosome, her mother and father must have it.

Question 27

What are alleles that are equally expressed (neither is dominant over the other) called? Give an example

Answer 27

Co-dominant alleles.

An example is X and Y sex chromosomes.

Question 28

When a trait is dominant or recessive on the X chromosomes, what is the particular inheritance patterns called?

Answer 28

Sex-linked trait.

Question 29

What is the most practical method in which to track human inheritance over many generations?

Answer 29

Pedigree charts.

Question 30

Why shouldn’t you reproduce with relatives?

Answer 30

It helps propagate genetic mistakes

Question 31

In gene therapy, what is the difference between In vivo and Ex vivo?

Answer 31

• In vivo: the genes are transferred directly into cells while still in the patient (internal)
• Ex vivo: the cells are taken from the patients and the genes of the cells are modified in a lab (external) then the cells are transferred back into the patient.