Mod A Unit 2, Les 5 Punnett Squares And Pedigrees

Question 1

What is a Punnett Square?

Answer 1

A graphic used to predict the POSSIBLE genotypes of offspring in a given cross

Question 2

Who created the Punnett Square?

Answer 2

Gregor Mendel

Question 3

What is meant by a genotype?

Answer 3

This is the combination of alleles that you inherit from your parents. (For example B = blue eyes, b = green eyes. Your genotype could be Bb, BB, bb. (The actual combination made)

Question 4

What is meant by a phenotype?

Answer 4

This refers to the observable traits you have no matter what your genotype. Example: B is blue eyes, b is green eyes. Your genotype could be BB or Bj. Your Phenotype is that you have blue eyes. (Does not matter how you got them) (see p.139)

Question 5

True or False: A Punnett square tells you the exact results a certain combination of alleles will make.

Answer 5

False: It only helps you find the probability it’s that a certain genotype will occur.

Question 6

What is probability?

Answer 6

The mathematical chance of a specific outcome in relation to the total number of possibilities. It can be expressed in the form of a ratio. (Practice on p. 141)

Question 7

What is a pedigree?

Answer 7

It is a tool to help study patterns of inheritance through generations of a family.

Question 8

What are sex-linked disorders?

Answer 8

These are ones associated with an allele coming from a sex chromosome. For example, a woman has XX for sex chromosomes. She can carry an allele for colorblindness. XX = she has it, Xx she is a carrier (meaning she doesn’t have it, but can pass it on) Practice on p. 142