Topic 3 - Monohybrid Inheritance And Genetic Diagrams

Question 1

What do family trees show?

Answer 1

The inheritance of different phenotypes over generations in the same family.

Question 2

What is a monohybrid cross?

Answer 2

A cross that looks at the probability of the offspring of two parents having certain genotypes and phenotypes.

Question 3

What diagram is used to visualize the combinations of alleles from parents?

Answer 3

Punnett square diagram.

Question 4

What do uppercase letters represent in genetic notation?

Answer 4

Dominant characteristics.

Question 5

What do lowercase letters represent in genetic notation?

Answer 5

Recessive characteristics.

Question 6

In a Punnett square, what is the chance of having an offspring who is homozygous dominant (BB)?

Answer 6

¼ chance.

Question 7

Fill in the blank: A monohybrid cross looks at the probability of the offspring of two parents having certain _______.

Answer 7

[genotypes and phenotypes]

Question 8

What is the purpose of a Punnett square?

Answer 8

To predict the genotype and phenotype probabilities of offspring.

Question 9

What does homozygous dominant mean?

Answer 9

Having two dominant alleles (BB).

Question 10

True or False: You can choose any letter to represent alleles in genetic notation.

Answer 10

True.

Question 11

What is the typical choice of letters used for simplicity in genetic notation?

Answer 11

A or B.

Question 12

What is the significance of family pedigrees in genetics?

Answer 12

They show how a condition (or the allele causing it) is passed down through generations

Pedigrees help visualize inheritance patterns and identify carriers of genetic conditions.

Question 13

How do we represent males and females in family pedigrees?

Answer 13

Males are represented by squares and females by circles

This visual distinction helps in tracking inheritance patterns.

Question 14

What do black shapes represent in a family pedigree?

Answer 14

Affected individuals

Black shapes indicate individuals who exhibit the trait or condition being studied.

Question 15

What do white shapes represent in a family pedigree?

Answer 15

Unaffected individuals

White shapes indicate individuals who do not exhibit the trait or condition.

Question 16

What does a line through a shape mean in a family pedigree?

Answer 16

The individual is deceased

This notation helps track the lineage and history of the family.

Question 17

What does a line passing directly between two shapes indicate?

Answer 17

The two individuals are partners

This shows a marital or partnership relationship in the pedigree.

Question 18

What does a line overhanging a group of individuals signify?

Answer 18

They are siblings

This notation indicates that the individuals share at least one parent.

Question 19

What is the relationship between Bb (heterozygous recessive) offspring and symptoms?

Answer 19

Symptoms depend on whether the condition is recessive or dominant

This highlights the role of dominant and recessive alleles in expressing traits.

Question 20

Fill in the blank: Recessive alleles normally ‘skip a _______.’

Answer 20

generation

This phenomenon occurs when carriers do not express the trait but can pass it to their offspring.

Question 21

True or False: A homozygous recessive offspring can occur if both parents have the allele.

Answer 21

False

If both parents have the allele, homozygous recessive offspring are not possible.