Chapter 5 - Genetics (Unit 2)

Question 1

What are Inheritance Patterns?

Answer 1

• Predictable patterns (transmission of traits)
• Inherited traits -> hereditary traits

Question 2

What did Gregor Mendel do?

Answer 2

• Studied pea plants + Inheritance patterns

Question 3

What is Locus?

Answer 3

• location of a gene on a region of a chromosome

Question 4

What is the P generation?
What is the F1 generation?
What is the F2 generation?

Answer 4

P - parental generation
F1 - First generation + hybrid (PxP)
F2 - Second generation (F1 x F1)

Question 5

What is Genotype?

Answer 5

• The genetic make-up of an organism
  Ex: set of genes/alleles

Question 6

What is Phenotype?

Answer 6

• Physical expression/appearance that an organism shows (Ex: looks)

Question 7

What are Hybrids?

Answer 7

• Cross of two diff true breeding organisms
• F1 generation

Question 8

What are Monohybrids?

Answer 8

• Offspring of parents diff in only one trait/gene

Question 9

What does Homozygous mean?

Answer 9

• Both alleles are dom or recess
  (Ex: BB/bb)

Question 10

What does Heterozygous mean?

Answer 10

• Alleles are always dom AND recess
• Dom always shows
  (Ex: Bb)

Question 11

What are Alleles?

Answer 11

• exist in genes
• Either dominant or recessive
• Homozygous or Heterozygous
• Each gamete only carries 1 allele for each trait

Question 12

What is Mendel’s Law of Segregation?

Answer 12

• During gamete formation
• Pair of alleles responsible for each trait separate -> each gamete has one allele for each trait

Question 13

What is Mendel’s Law of Independent Assortment?

Answer 13

• During gamete formation
• Alleles segregate independently of each other
  Ex: One trait is not accompanied by another
  (Ex: Blue eyes + Blonde hair)

Question 14

What is a Dihybrid Cross?

Answer 14

• Involves two separate traits
• Ex: colour and length

Question 15

Describe Incomplete Dominance

Answer 15

• Mix of traits
• An Inheritance pattern where the phenotype of a heterozygous individual falls in bw both parent’s phenotypes
• Same letter is used (Ex: R & r )
  Ex: Snap Dragons

Question 16

Describe Codominance

Answer 16

• Both traits show separately
• Both alleles are completely expressed at the same time
• Is heterozygous + has its own phenotype
• Different letters are used (Ex: R + W)
  Ex: Cattle (Red + White -> Roan)
  Ex: Blood type is Codominant

Question 17

What are Multiple Alleles?

Answer 17

• Many genes have more than 2 alleles
  Ex: ABO blood type

Question 18

Describe Blood Types + Alleles

Answer 18

Four types:
1. A
2. B
3. AB
4. O

I to the pwr of A
I to the pwr of B (Co- dominant)
i is recessive

Question 19

Describe Blood type A

Answer 19

• Possesses A carbohydrates
• Has Anti-B

Question 20

Describe Blood type B

Answer 20

• Possesses B carbohydrates
• Has Anti-A

Question 21

Describe Blood type AB

Answer 21

• Has carbohydrates A + B
• No Anti Bodies
• Universal recipient

Question 22

Describe Blood type O

Answer 22

• Has NO carbohydrates
• Has Anti - A&B
• Universal Donor

Question 23

What is a Polygenic Trait?

Answer 23

• Has a range of phenotypes
• Additive effects of multiple genes
  (Ex: eye colour/height)
• 60 genes -> skin colour

Question 24

What are Environmental Influencers?

Answer 24

• Diff allele combinations = variety in phenotypes
• Nature (heredity)
• Nurture (environment)
• Influence phenotype
  (Ex: humans -> nutrition and sunlight can impact growth)

Question 25

What is Hemophilia?

Answer 25

• Excessive + unexplained bleeding
• Spread in royal families
• Inherited traits -> Males (X-linked)

Question 26

What is the chromosome theory of inheritance?

Answer 26

• Genes located at specific positions of chromosomes
• Segregation + Assortment during meiosis
  -> responsible for inheritance patterns
• Chromosomes assort independently
  (4 unique possible genotypes in gametes)

Question 27

What is Genetic Linkage?

Answer 27

• Tendency for alleles for diff genes on the same chromosome to be inherited together
• Genes with close loci = linked genes
  -> closer = stronger Linkage
  -> father apart -> more likely crossing over will separate them

Question 28

What are sex-linked genes?

Answer 28

• Any gene linked on a sex chromosome
• In humans, most found on X
  Ex: Fruit flies -> white/red eyes
  Female: XX
  Male: XY (only 1 X, therefore more susceptible)

Question 29

What are some sex-linked disorders?

Answer 29

1. Hemophilia
2. Red-green colorblindness
3. Duchenne muscular dystrophy
   *Some rare genes located on the y-chromosome can be passed