Chapter 8: 8.1 More Complex Genetics [Blood Type, Pleiotropy, Epistasis and Polygenic Inheritance]

Question 1

What are the blood types that a human can have?

Answer 1

• Type A
• Type B
• Type AB
• Type O

Question 2

What are blood types determined by?

Answer 2

• Type of carbohydrate added to a protein on the surface of red blood cells
• 3 different enzymes responsible for adding this carbohydrate

Question 3

True or False:

The three different enzymes responsible for adding carbohydrates to proteins are encoded by the same alleles

Answer 3

False, they are encoded by three different alleles

Question 4

Blood Type:

What enzymes are responsible for adding different carbohydrates?

Answer 4

• I(A) adds “A” type carbohydrate
• I(B) adds “B” type carbohydrate
• i does not add carbohydrates

Question 5

True or False:

Blood type is determined by which alleles the person has

Answer 5

True

Question 6

Blood Type:

Blood type alleles
* I(A)I(A)

Answer 6

Type A blood

Question 7

Blood Type:

Blood type alleles
* I(A)i

Answer 7

Type A blood

Question 8

Blood Type:

Blood type alleles
* I(A)I(B)

Answer 8

Type AB blood

Question 9

Blood Type:

Blood type alleles
* I(B)I(B)

Answer 9

Type B blood

Question 10

Blood Type:

Blood type alleles
* I(B)i

Answer 10

Type B blood

Question 11

Blood Type:

Blood type alleles
* ii

Answer 11

Type O blood

Question 12

Blood Type:

Distinguish blood types by the type of carbohydrates they have

Answer 12

• Type A blood: “A” type carbohydrates
• Type B blood: “B” type carbohydrates
• Type AB blood: “A” and “B” type carbohydrates
• Type O blood: No carbohydrates

Question 13

Pleiotropy:

What can be the result of a mutation in a pleiotropic gene?

Answer 13

Can have a broad range of phenotypes associated with it

Question 14

Pleiotropy:

Pleiotropic genes (Pleiotropy)

Answer 14

Can control multiple different seemingly unrelated traits

Question 15

Phenylketonuria is an example of…

Answer 15

Pleiotropy

Question 16

What is phenylketonuria?

Answer 16

Genetically inherited condition that has to do with levels of the amino acid phenylalanine

Question 17

What is the genetic cause of phenylketonuria?

Answer 17

A mutation in the gene that codes for an enzyme responsible for breaking down phenylalanine into tyrosine

Question 18

What does phenylketonuria lead to? (signs and symptoms)

Answer 18

Toxic build up of phenylalanine in the body and low levels of tyrosine
* Nerve damage, mental disorders
* Developmental problems (abnormal gait and posture)
* Seizures
* Skin rashes and fair skin

Question 19

Epistasis

Answer 19

When two or more genes contribute to a phenotype, and the phenotype of one gene is altered by the presence of another

Question 20

Alleles and genes can interact with each other to give…

Answer 20

Different phenotypes

Question 21

True or False:

Epistasis is when one gene contributes to a phenotype

Answer 21

False, it is when TWO OR MORE GENES contribute to a phenotype

Question 22

Polygenic Inheritance

Answer 22

Some traits are determined by the combination of multiple genes
* Known as polygenic inheritance

Question 23

True or False:

Environment can have an effect on the phenotype

Answer 23

True, environment and genes both can determine phenotypes