4 - 3 Genetics and Heredity

Question 1

Traits

Answer 1

Genes found on chromosomes in the nucleus of a cell, code for the inherited characteristics

Question 2

Heredity

Answer 2

The passing of traits from parents to offspring

Question 3

Genetics

Answer 3

The scientific study of heredity

Question 4

Physical appearance and mathematics

Answer 4

Lacking today’s technology, the first studies of genetics basics

Question 5

Gregor Mendel

Answer 5

• An Australian monk who loved gardening and mathematics.
• He designed simple experiments with pea plants to determine how heritable traits were transferred from one generation to the next.

Question 6

Mendel’s Conclusions

Answer 6

• Each trait is controlled by two genes that they receive from their parents.
• Some genes are dominant over others (shown in capital letters).
• Genes that are masked by dominant genes are called recessive genes (shown in lowercase letters).
• The combination of these two genes determines the traits offspring will exhibit.
• How often these traits will appear is predictable

Question 7

Genotype

Answer 7

Actual genetic code (Bb)

Question 8

Phenotype

Answer 8

The way genes are expressed; what is seen on the outside

Question 9

Purebred (Homozygous)

Answer 9

Having two identical genes for a trait (BB or bb)

Question 10

Hybrid (Heterozygous)

Answer 10

Having two different genes for a trait (Bb)

Question 11

Reginald Punnett

Answer 11

Based on the work of Mendel, he developed the “Punnett Square” as a method of predicting the results of a genetic cross (breeding).

Question 12

Dominant genes

Answer 12

Symbolized by capital letters

Question 13

Recessive genes

Answer 13

Symbolized by lowercase letters

Question 14

Principles of Genetics

Answer 14

• Inherited traits are passed on from parents to offspring.
• The traits of an organism are controlled by genes.
• Organisms inherit genes in pairs. One gene comes from each parent.
• Genes can be dominant or recessive. Dominant genes can mask recessive genes.
• A Punnett square can be used to predict the results of a cross.

Question 15

Incomplete Dominance

Answer 15

Blending of traits in the hybrid genotype

Question 16

Codominance

Answer 16

Both traits are shown in the hybrid genotype

Question 17

Sex-linked Traits

Answer 17

Specific traits linked to the X or Y chromosomes

Question 18

Allele

Answer 18

Gene options

• Ex. Red Gene or White Gene
• Ex. Blood Types – A Gene, B Gene, O Gene