mendelian genetics

Question 1

what is P in terms of generation of cross-breeding?

Answer 1

parental gen (true-breeding)

Question 2

what is F1 in terms of generation of cross-breeding?

Answer 2

filial gen (offspring from that true breeding)

Question 3

what is a gene?

Answer 3

Information that is passed on from parents to offspring if the information is packaged as discrete particles.

Question 4

what are alleles?

Answer 4

• individuals have 2 copies of each gene, one inherited from the mother and the other from the father.
• Genes controlling a trait can differ - these different forms of a gene are called alleles

Question 5

how many copies of genes and alleles are present in each gamete?

Answer 5

one

Question 6

where do the genes reside?

Answer 6

The genes for a particular trait reside at a specific
locus (position) on a certain chromosome

Question 7

what is a genotype?

Answer 7

combination of alleles (RR,rr,Rr)

Question 8

what is homozygous?

Answer 8

two of the same allele (RR,rr)

Question 9

what is heterozygous?

Answer 9

one of each allele (rR, Rr)

Question 10

what is Mendel’s law explained through?

Answer 10

Both laws are explained by chromosomal behavior
during Meiosis

Question 10

what is Mendel’s 1st Law?

Answer 10

Law of Segregation

Question 11

Explain Mendel’s 1st Law

Answer 11

Genes segregate at meiosis so that
each gamete contains only one of the
two possessed by the parent

Question 12

when during meiosis 1 do R and r segregate?

Answer 12

Anaphase 1

Question 13

what happens in meiosis 2 after the R and r segregate in anaphase 1?

Answer 13

Following Meiosis II, each gamete has just one unreplicated copy of each chromosome and
thus one allele per pair of genes

Question 14

what is Mendel’s 2nd law?

Answer 14

independent assortment (A Dihybrid Cross)

Question 15

what does hybrid mean?

Answer 15

means the alleles are heterozygous

Question 16

when is it a dihybrid cross?

Answer 16

when something is heterozygous at two different genes (RrYy)

Question 17

what does the 9:3:3:1 phenotypic ratio mean for a dihybrid cross?

Answer 17

it reflects all the combinations in the cross

Question 18

explain Mendel’s 2nd law

Answer 18

Alleles of different genes assort
independently during gamete formation

Question 19

what is the phenotypic ratio of a dihybrid cross

Answer 19

9:3:3:1

Question 20

how do you explain independent assortment through meiosis?

Answer 20

As a cell reaches Metaphase I of meiosis, the paired homologous can line up one of two ways

Question 21

does it matter where the different alleles go when they line up during independent assortment?

Answer 21

Where R or r goes does not determine where Y or y goes - determines by chance