Chapter 14 - Mendelian Genetics

Question 1

What did Mendel’s particulate hypothesis theorize?

Answer 1

That some trait is being passed from parent to child

Question 2

What are alleles?

Answer 2

The physical expression of a gene located on a chromosome (aka active trait)

Question 3

Why did Mendel choose pea plants as his model study subject?

Answer 3

Because pea plants are easily accessible, can easily be pollinate with various other pea plants and they produce offsprings quickly

Question 4

What are the parental generation in the pea plants?

Answer 4

The very first two plants that are cross pollinated

Question 5

What’s the concept of true breeding?

Answer 5

True breeding involves in offsprings that have homozygous traits, the same as their parents did (TT)

Question 6

What’s F1 generation in context of the pea plant experiment?

Answer 6

The offsprings of P generation plants, they are a hybrid between two true breeding generations.

Only one physical characteristic is expressed

Question 7

What are F2 generations in context of the pea plant experiment?

Answer 7

F2 generations are the offsprings of the hybrid generation F1. In these generations, we can see variability in traits in a orderly ratio. (3:1)

Question 8

Did the F1 generation ever produce white flowers in Mendel’s experiment?

Answer 8

No, they never produced white flowers because the hybrid generation only expressed either one characteristic every single time they were crossed over.

Question 9

What laws did Mendel come up with from the experiment?

Answer 9

1. Alleles exist that cause some characteristic to be passed on to offsprings
2. There is only one allele for each characteristic that’s passed on from each parent (aka TT and Tt)
3. One allele is more dominant/prevalent than the other in an offspring
4. During meiosis, alleles from each parents seperate causing only one allele to be passed on

Question 10

Are alleles just genes?

Answer 10

Yes, they are the genes on chromosomes but alleles refer to specific traits such as eye color on the chromosome.

Question 11

What are homozygous traits and what are heterozygous traits?

Answer 11

Homozygous traits contain two alleles that are the same (PP)

Heterozygous traits contain two different alleles (Pp)

Question 12

How exactly are the alleles of the same trait different?

Answer 12

one can be more recessive and one can be more dominant than the other

Question 13

F1 generations alleles are reffered as being completely

Answer 13

Homozygous

Question 14

F2 alleles can be both

Answer 14

Heterozygous and homozygous

Question 15

What is the sequence of DNA that’s been written for a particular allele called?

Answer 15

Genotype

Question 16

What’s the physical manifestation of an allele called?

Answer 16

Phenotype

Question 17

What did mendel figure out by crossing the green and wrinkled and yellow and smooth pea plants together?

Answer 17

That when alleles of two different traits are indepdent, they provide more variation in the offsprings.

However if the alleles of traits were on the same chromosome, the result would have been something more simpler.

Question 18

Why do the probability laws apply to genetics?

Answer 18

Because the alleles and their dominance/reccessiveness governs the likeliness of allele distribution in offsprings

Question 19

What probability laws apply specifically?

Answer 19

Multiplication rule = applies to independent events (when alleles on different chromosomes)
Addition rule = applies to mutually exclusive events

Question 20

How does the multiplication rule apply to the genotypes?

Answer 20

The multiplication rule applies to the genotypes because we multiple the alleles of two parents against each other

Question 21

How does the addition rule apply to the phenotypes?

Answer 21

To calculate the ratios, all the similar offspring’s alleles are added up.

Question 22

What’s the concept of incomplete dominance?

Answer 22

When F1 hybrids’s parents alleles are neither dominant or reccesive over one another, it results into a mixed result

Question 23

What is codominance?

Answer 23

Codominance is when there no allele can mask the other allele’s appeareance. So black and white alleles aren’t blocking or masking each other and when an offspring has both, both of them show up.

AB Blood type is an example - when both blood types show up because neither blood type is actually blocking the other.

Question 24

What does epistasis do?

Answer 24

When there’s a gene for a particular characteristic whose expression is being controlled by another gene.

So in allele GgKk, the allele Gg is controlling whether Kk is shown or not

Question 25

What’s the difference between polygenetic inheritance and epistasis?

Answer 25

The difference between them is that polygenetic inheritance causes a range of different results but epistasis causes 3 major seperate results

Question 26

What is polygenetic inheritance?

Answer 26

When a characteristic is controlled by more than one gene such as color being determined by multiple different genes. This causes a wide range of phenotypes to occur.

Question 27

Does environment change genetics?

Answer 27

It can influence them

Question 28

How exactly does the environment change the genetic expression in organisms?

Answer 28

The environment’s different elements’ presence can change the gene expression. So two exactly same genotypes can actually have very different results depending on what exists in environment.

Question 29

Why are pedigrees helpful?

Answer 29

They help analyze what the offsprings’ phenotypic expression can be like