UNIT 1 | GENETICS + HEREDITY

Question 1

Law of Dominance

Answer 1

Some traits can mask other traits when both traits appear in the parents

Question 2

Law of Segregation

Answer 2

During the formation of the reproductive cells the paired factors (genes) separate from one another and then recombine

Question 3

Law of Independent Assortment

Answer 3

Each trait is inherited independent of one another

Question 4

What is the one exception to the law of independent assortment

Answer 4

Blonde hair and blue eyes

Question 5

Incomplete Dominance

Answer 5

Two alleles are neither dominant nor recessive. Both contribute to the phenotype of the offspring (a sort of blending). An example of this is snap dragons

Question 6

Co-dominance and Multiple Alleles

Answer 6

Two alleles may contribute equally in the offspring and are both dominant
An example of this is a speckled offspring of a white chicken and a black rooster

Question 7

Sex-Linked Traits

Answer 7

All organisms that reproduce sexually have a combination of X and Y chromosomes (Male, XY; Female, XX)

Question 8

Non Disjunction

Answer 8

Failure of homologous chromosomes or sister chromatids to separate during cell division

Question 9

What is a pedigree?

Answer 9

A diagram that shows the occurrence of a particular phenotype of a genetic trait from one generation to the next within a biological family

Question 10

Describe a test cross

Answer 10

A genetic cross between homozygous recessive and a suspected heterozygous to determine the genotype

Question 11

Describe a karyotype

Answer 11

A micrograph showing the number and visual appearance of the chromosomes

Question 12

Describe meiosis

Answer 12

Cell division that results in four daughter cells each with half the chromosomes as the parent. The formation of gametes.

Question 13

Name two cells that become a sperm and an egg

Answer 13

Oogonial (egg, ovary)
Spermatogonial (sperm, testes)

Both are diploid (2N)

Question 14

P
F1
F2

Answer 14

Parental Generation
First filial generation
Second filial generation

Question 15

Why do two heterozygous tall plants create three tall plants and one short plant?

Answer 15

The paired genes separate and recombine (law of segregation)

TtxTt=TT, Tt, Tt, tt (3:1)

Question 16

Define heredity

Answer 16

The passing of traits from parent to offspring

Question 17

Define factor

Answer 17

Describing a gene

Question 18

Define gene

Answer 18

Trait

Question 19

Define allele

Answer 19

A form of a trait

Question 20

Define acquired trait

Answer 20

Trait that has been learned (ex scars or attitude)

Question 21

Define inherited trait

Answer 21

Trait passed from parent or ancestor to offspring (ex eye colour)

Question 22

Define autosome

Answer 22

Non sex chromosome

Question 23

Define carrier

Answer 23

A female that caries a gene but does not express it in her phenotype (ex hemophilia; XRXr)

Question 24

Define chromosome

Answer 24

Threadlike structure carrying genetic information in the form of genes

Question 25

Define diploid

Answer 25

A cell that contains two sets of homologous chromosomes

Question 26

Define fertilization

Answer 26

During sexual reproduction, an egg and sperm combine to form a zygote

Question 27

Define gamete

Answer 27

Sex cell (sperm of egg)

Question 28

Define genotype

Answer 28

Symbolic representation of a characteristic

Question 29

Define haploid

Answer 29

A cell that contains only a single set of genes

Question 30

Define heterozygous

Answer 30

Having two different alleles for a particular gene

Question 31

Define homozygous

Answer 31

Having two identical alleles for a particular gene

Question 32

Define homologous

Answer 32

Chromosomes in which one set comes from the male parent and one set from the female parent

Question 33

Define multiple alleles

Answer 33

Three or more alternative forms of a gene

Question 34

Define nondisjunction

Answer 34

Failure of homologous chromosomes or sister chromatids to separate during cell division

Question 35

Define phenotype

Answer 35

Physical characteristic of an organism

Question 36

Define tetrads

Answer 36

Four chromatids in groups of two formed in prophase one

Question 37

Define synapsis

Answer 37

Fusion of chromosome pairs at the start of meiosis that enables crossing over to occur

Question 38

Define autosomal recessive

Answer 38

Two copies of abnormal gene must be present in order to develop a disease

Question 39

Define autosomal dominant

Answer 39

One copy of abnormal gene from one parent needed to get a disease

Question 40

Define purebred

Answer 40

Organism that is the offspring of genetically similar parents that were both homozygous for a trait

Question 41

Define hybrid

Answer 41

Organism that is the offspring of genetically dissimilar parents

Question 42

Define dominant

Answer 42

Expressed in phenotype

Question 43

Define recessive

Answer 43

Only expressed in phenotype when paired with another recessive allele

Question 44

Define meiosis

Answer 44

Process in which a number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell