Chapter 5

Question 0

Define true breeding organism

Answer 0

An organism that produces offspring identical in appearance to itself, generation after generation

Question 1

Define trait

Answer 1

A specific characteristic or feature exhibited by an organism

Question 2

Define cross-fertilization

Answer 2

The fertilization of a female gamete from one organism with the male gamete of another

Question 3

Define parent generation (p generation)

Answer 3

Organisms that are initially crossed and are usually true breeding

Question 4

Define first filial generation (f1 generation)

Answer 4

The offspring of a cross of P generation

Question 5

Define second filial generation (f2 generation)

Answer 5

The offspring of a cross between the F1 generation

Question 6

Define hybrid

Answer 6

Offspring that result from crossing two true breeding varieties of the same species

Question 7

Define mono hybrid

Answer 7

The offspring produced from parents that differ in just one trait

Question 8

Define mono hybrid cross

Answer 8

The cross of two individuals that differ by one trait

Question 9

Define allele

Answer 9

A specific form of a gene

Question 10

Define dominant

Answer 10

The form of a trait that always appears when an individual has an allele for it

Question 11

Define recessive

Answer 11

The form of a trait that only appears when an individual has two alleles for it

Question 12

Define homozygous

Answer 12

Having two identical alleles for a trait

Question 13

Define heterozygous

Answer 13

Having two different alleles for a trait

Question 14

Define genotype

Answer 14

The combination of alleles for any given trait or the genetic make up for an organism

Question 15

Define phenotype

Answer 15

The physical traits of an organism

Question 16

Define Punnett square

Answer 16

A grid used to illustrate all possible genotypes and phenotypes of offspring from genetic crosses

Question 17

Define test cross must edit

Answer 17

A cross between a parent of unknown genotype and a homozygous recessive parent

Question 18

Define dihybrid

Answer 18

Offspring produced from parents that differ in two traits

Question 19

Define dihybrid cross

Answer 19

A cross of two individuals that differ in two traits due to two different genes

Question 20

Who is Gregor Mendel?

Answer 20

He was an Austrian monk in the 1850s that begin experiments that help explain inheritance patterns. He worked with pea plants in the monastery garden. He hypothesized that parents passed down distinct factors to their offspring & were responsible for hereditary traits.

Question 21

Describe Mendels true breeding cross

Answer 21

He chose 7 traits that were expressed in 2 forms. These plans were called the P generation. When crossed, the offspring was called F1 generation. This type of cross is called mono hybrid cross.

Question 22

What is the Mendelian ratio?

Answer 22

The F2 generation produces a 3:1 ratio

Question 23

What is Mendel called because of his work?

Answer 23

The Father of Genetics

Question 24

What does the law of segregation state?

Answer 24

It states that traits are determined by pairs of alleles that segregate during meiosis so that each gamete receives one allele.

Question 25

What does the law of independent assortment state?

Answer 25

It states that is genes are located on separate chromosomes, they will be inherited independently of one another.

Question 26

What is a pedigree?

Answer 26

It is a type of flowchart that uses symbols to show inheritance patterns of traits in the family over many generations. Geneticist can use a pedigree to show how traits, controlled by a single gene or multiple genes, run through a family. This is useful for predicting diseases within a family line.

Question 27

Define incomplete dominance

Answer 27

A situation where neither allele dominates the other & results in partial expression of both traits (blending).

Question 28

Define codominance

Answer 28

A situation where both alleles are expressed fully to produce offspring with a third phenotype

Question 29

What is an example of incomplete dominance?

Answer 29

Snapdragons. C^RC^R x C^WC^W crossed to make C^RC^W (pink).

Question 30

What is an example of codominance?

Answer 30

Shorthorn cattle: red bull + white cow = roan cow

Question 31

What are the three alleles for human blood?

Answer 31

I^A, I^B, i

Question 32

What are the four different types of human blood?

Answer 32

A, B, AB, O

Question 33

What are the alleles possible for each different blood type?

Answer 33

A - I^AI^A or I^Ai
B - I^BI^B or I^Bi
AB - I^AI^B
O - ii

Question 34

Define linked genes

Answer 34

Some traits don’t follow Mendel’s law of independent assortment and are often inherited together. They are found on the same chromosome and do not sort independently. The unlinking of these genes can only happen if crossing over occurs during gamete formation.

Question 35

What is a sex-linked gene?

Answer 35

Any gene located on the X or Y chromosome. For humans, most sex linked genes are found on the X chromosome since it is much larger than the Y chromosome.

Question 36

What are sex-linked traits?

Answer 36

Traits controlled by X-linked or Y-linked genes. Many are genetic disorders (ie, red-green colour blindness & hemophilia).