Exam 3- Genetics

Question 1

What is an allele?

Answer 1

alternate forms of an allele
- homozygous
- heterozygous

Question 1

What is a gene?

Answer 1

unit of inheritance; basics of every characteristic

Question 2

What are the Mendelian patterns of inheritance?

Answer 2

Organisms attain diversity of form, function, and behavior through hereditary modifications

Question 3

What is the importance of different sequences of nucleotides in DNA?

Answer 3

• genetic differences
• enzyme differences
• appearance differences

Question 4

What was Hippocrates’ early idea of genetics?

Answer 4

• 1st known expansion of hereditary pangenesis
• seeds produced and passed on during conception

Question 5

What was Aristotles early idea of genetics?

Answer 5

Male and female semen produced flesh and blood offspring

Question 6

What was the idea of spontaneous generation?

Answer 6

the supposed production of living organisms from nonliving matter, as inferred from the apparent appearance of life in some supposedly sterile environments.

Question 7

What was the blending concept of inheritance?

Answer 7

black mouse + white mouse DOES NOT EQUAL gray mouse

Question 8

What is experience-dependent inheritance?

Answer 8

• changed back on generations by adapting to the environment
• behavioral changes modify traits inherited by offspring

Question 9

Gregor Medel

Answer 9

• inheritance in common pea
• formulated fundamental laws or heredity in the 1860s
• no knowledge of cells or chromosomes or microscope
• right organism, right experiment, right analysis

Question 10

What are traits?

Answer 10

characteristics
- ex. wrinkled v.s smooth

Question 11

characteristic vs. trait example?

Answer 11

characteristic:
stem length

trait:
tall or short

Question 12

What are the parental plants? what are their offspring called?

Answer 12

The first two plants crossed
- their offspring are called F1

Question 13

What was interesting about Medel’s f2 results?

Answer 13

• in every case of F2 results Mendel saw a 3: 1 ratio
• 3 dominant
• 1 recessive

Question 14

What is a monohybrid cross?

Answer 14

• true breeding
• choose variants that only vary in one trait
• performed reciprocal crosses
  Parental gen = P0
  First filial generation offspring = F1
  Second filial generation offspring = F2
  Formulated Law of Segregation

Question 15

What is true breeding?

Answer 15

• exact same characteristic
• homozygous plants

Question 16

What is the Formulated Law of Segregation?

Answer 16

1:2:1

TT: Tt: tt ( Genotype Ratio)

3: 1
tall: short ( Phenotype Ratio)

Question 17

Law of Segregation

Answer 17

• each individual has a pair of factors ( alleles) for each trait
• the factors ( alleles) separate ( segregate) during gamete formation
• each egg or sperm has only one
• fertilization gives offspring two factors for each trait

Question 18

Genotype? Phenotype?

Answer 18

• genes in cells
• physical manifestation of genes

Question 19

Principle of Dominance?

Answer 19

• dominant allele ( A ) masks expressing of recessive allele (a)

Question 20

Test Cross?

Answer 20

• Individuals with recessive phenotype always have the homozygous recessive genotype ( gg)
• individuals with dominant phenotype have intermediate genotype

Question 21

Dihybrid Cross?

Answer 21

• true breeding plants differing in TWO traits
• F1 plants= both dominant characteristics
• observed phenotypes among F2 plants
• Formulated Law of Independent Assortment

Question 22

What is the Formulated Law of Independant Assortment?

Answer 22

9:3:3:1
- 3:1 tall/short
- 3:1 green/yellow

• a pair of factors for one trait segregate independently of the factors for other traits ( on nonhomologous chromosomes)
• all possible combinations of factors can occur in gametes

Question 23

Multiplicative law?

Answer 23

Mendel’s second law, the law of independent assortment, states that the alleles of one gene segregate into gametes independently of the alleles of another gene.