17.1 Laying Foundations

Question 1

What is selective breeding?

Answer 1

The process of choosing and breeding specific organisms for particular physical features or behaviors

Question 2

What was Aristotle’s view on Inheritance?

Answer 2

Egg and Sperm consist of particles from all parts of the body called pan-genes which develop into the parts of the body from which they are derived

Question 3

What is Leeuwenhoek believe about inheritance?

Answer 3

He believed that sperm consisted of a single tiny human living in the head of the sperm

Question 4

What do true breeding plants do?

Answer 4

Exhibit the same characteristics generation after generation

Question 5

What is a mono-hybrid cross?

Answer 5

The offspring of a cross between two parent organisms with different inheritable traits

Question 6

How did Mendel test traits?

Answer 6

He cross bred parental plants with other parental plants and observed the characteristics of the offspring and the offspring’s offspring

Question 7

What is complete dominance?

Answer 7

An individual with one recessive and one dominant form had the same observable physical characteristics as an individual with two dominant forms

Question 8

What generalizations did Mendel infer?

Answer 8

• Discrete genes determine individual traits
• Each individual organism has two copies of each gene
• When gametes are formed, the copies of each factor segregate so that each gamete receives one copy of each gene
• Eggs and sperm fuse randomly. The embryo that develops into a new individual has two copies of each factor -one copy from each parent

Question 9

What is the law of segregation?

Answer 9

A summary of Mendel’s generalizations

Question 10

Who coined the term Gene?

Answer 10

Danish Botanist and Geneticist Johannsen

Question 11

What are the different forms of each gene called?

Answer 11

Alleles ex. Gene is seed shape alleles are round and wrinkled

Question 12

What is used to represent a dominant allele and recessive allele?

Answer 12

The first letter in the description in upper case for dominant alleles and the first letter in lower case to represent recessive alleles

Question 13

What is an individuals Genotype?

Answer 13

The combination of alleles for any given trait

Question 14

What is an individuals Phenotype?

Answer 14

The outward expression of a trait -the physical expression you can observe

Question 15

What does Homozygous mean?

Answer 15

An individual with two identical alleles for a trait ex. RR or rr

Question 16

What does Heterozygous mean?

Answer 16

An individual with two different alleles for a trait ex. Rr

Question 17

How did recessive traits randomly appear in the F2 generation?

Answer 17

When the plants produced gametes, the alleles segregate randomly and each gamete only receives one allele giving an equal chance to receive another recessive trait

Question 18

What is a test cross?

Answer 18

A cross between an organism of an unknown genotype and a homozygus recessive organism

Question 19

When is a test cross used?

Answer 19

When geneticists want to know if a pheotypically dominant individual is homozygous or heterozygous

Question 20

What is a Dihybrid cross?

Answer 20

When plants that were true breeding for two different traits were crossed with plants that were true breeding for the opposite traits ex. TTGG x ttgg

Question 21

What is Mendel’s second law?

Answer 21

The two alleles for one gene assort independently of the alleles for other genes during gamete formation

Question 22

What is incomplete dominance?

Answer 22

A condition in which neither alleles for the same gene can completely conceal the presence of another

Question 23

What is sickle cell anemia caused by?

Answer 23

A specific form of a gene that directs the synthesis of hemoglobin which distort the shape of the cells causing blockages that result in tissue damage

Question 24

What is co-dominance?

Answer 24

When both alleles are fully expressed

Question 25

What is the chromosome theory of inheritance?

Answer 25

A theory proposed by Walter Sutton that genes are carried on chromosomes

Question 26

What were objections to Mendel’s and Suttons theories?

Answer 26

Many people believed that parental gens played a factor and environment played a role