Introduction to Mendelian Genetics

Question 1

What does filial (F1) mean?

Answer 1

The first generation (parent’s first offspring)

Question 2

What is a monohybrid cross?

Answer 2

A cross that shows the inheritance of one trait

Question 3

What is a dihybrid cross?

Answer 3

A cross that shows the inheritance of two traits

Question 4

Mendel originally thought that the different traits were because of blending, how did he reason against this when he discovered that the blending theory was wrong?

Answer 4

The results of the pea experiment can be explained by:
- Information being handed down from parents through discreet packages (which we call genes).
- The genes that control the trait can differ (which we call alleles - the different variations of a gene)

Question 5

What is the locus?

Answer 5

The specific place on a chromosome where a certain gene is located

Question 6

Homozygous vs Heterozygous

Answer 6

Homozygotes have two of the same allele
Heterozygotes have one of each

Question 7

What is mendel’s first law?

Answer 7

The law of segregation. States that “genes segregate at meiosis so that each gamete contains only one of the two possessed by the parent.”
Following meiosis 2, each gamete has just one unreplicated copy of each chromosome and thus one allele per pair of gametes.

Question 8

What is mendel’s second law?

Answer 8

The law of independent assortment. States that “alleles of different genes assort independently during gamete formation.”
- Shown by a dihybrid cross
As a cell reaches metaphase 1 of meiosis, homologous pairs of chromosomes can line up one of two ways.