Unit 4 (Genetics) Exam Outline

Question 1

Genetics

Answer 1

Study of patterns in heredity and the variation of organisms.

Question 2

Heterozygous

Answer 2

two letters are different

Question 3

Genotypes

Answer 3

genetic makeup of an organism, consists of alleles that the organism inherits from its parents (the letters)

Question 4

Sex chromosomes

Answer 4

A chromosome that determines sex (gender)

Question 5

Crossing over

Answer 5

When 2 homologous chromosomes pair together and they cross each other. Some segments break off and reattach to the other chromosome.

Question 6

Somatic mutation

Answer 6

take place in an organism’s BODY cells and can therefore affect the organism.
Ex: certain types of skin cancer and leukemia results from somatic mutations.
Somatic mutations are NOT passed on to offspring.

Question 7

Universal donor

Answer 7

Type O blood, anybody can receive it because it has no antigens (substance that stimulates as immune response.) Can only take type O blood.

Question 8

Gene

Answer 8

a segment of DNA that contains coding for a polypeptide or protein; unit of hereditary information

Question 9

Incomplete dominance

Answer 9

heterozygous individual expresses both simultaneously WITH blending
ex: red flower & white flower = pink flower

Question 10

Sex linked

Answer 10

Traits whose genes are carried on an x or y chromosome.

Question 11

Germ-cell mutation

Answer 11

occur in the gametes (sperm and
egg cells). They can be inherited by the offspring but do not affect the individual themself.

Question 12

Chromosome mutation

Answer 12

either changes in the structure of a chromosome, or the loss of an entire chromosome.
See section 12-6 (page 225) of old text.

Question 13

Universal acceptor

Answer 13

Type AB blood because it can accept A, B, AB, or O blood, can only give to other type AB’s

Question 14

Alleles-

Answer 14

versions of a trait
Mendel’s factors are now called alleles. Controls the characteristics
The letters that show the genes from mom or dad. Alternate versions of a trait.
(One letter?)

Question 15

Phenotype

Answer 15

Appearance of an organism as a result of its genotype.
Ex: PP, Pp = purple flower
pp = white flower

Question 16

Autosomes

Answer 16

A chromosome that is not a sex chromosome. (Controls other traits)

Question 17

Linkage-

Answer 17

The genes located on one chromosome form a linkage group. Because they are on the same chromosome they tend to be inherited together.

Question 18

Gene mutation

Answer 18

Occurs when a single nucleotide (makes up DNA) is substituted, added or removed

Question 19

Pedigree

Answer 19

A diagram of the genetic history of an individual; can show how a trait is inherited over several generations.

Question 20

Mutation

Answer 20

a change (or error) in the DNA of an organism.

Mutations can involve an entire chromosome or a single
DNA nucleotide (A C T G) and can take place in ANY cell.

Question 21

Somatic mutation

Answer 21

take place in an organism’s BODY cells and can therefore affect the organism.
Ex: certain types of skin cancer and leukemia results from somatic mutations.
Somatic mutations are NOT passed on to offspring.

Question 22

Lethal mutation-

Answer 22

Cause death, often before birth.

Ex: any mutation that causes a miscarriage.
Ex: Albinism in wild animals would result in death shortly after birth because the animal would develop skin cancer faster, and be more vulnerable to predators.

Question 23

Chromosome mutation

Answer 23

either changes in the structure of a chromosome, or the loss of an entire chromosome.
See section 12-6 (page 225) of old text

Question 24

Gene mutation

Answer 24

Occurs when a single nucleotide (makes up DNA) is substituted, added or removed

Question 25

Segregation

Answer 25

Pairs of gene variants are separated into reproductive cells.

Question 26

Independent assortment

Answer 26

During meiosis, the random distribution of genes from different chromosomes to gametes.

Question 27

Linked

Answer 27

Two or more genes on the same
chromosome are said to be LINKED. Because they are on the same chromosome, linked genes tend to be inherited together - this is the OPPOSITE of Mendel’s Law of Independent Assortment!

Question 28

Karyotype

Answer 28

photomicrograph of the chromosomes in a dividing cell found in a normal human. Notice that the 46 human chromosomes exist as 22 homologous pairs of autosomes and 2 sex chromosomes (XX in female, XY in males. See Fig 8-3 p147 of old text.

Question 29

Huntington’s disease

Answer 29

uncontrolled movement of the arms, legs, head, face and upper body

an inherited disorder that causes nerve cells (neurons) in parts of the brain to gradually break down and die. The disease attacks areas of the brain that help to control voluntary (intentional) movement, as well as other areas.

Question 30

Hemophilia

Answer 30

a rare disorder in which the blood doesn’t clot in the typical way because it doesn’t have enough blood-clotting proteins (clotting factors). If you have hemophilia, you might bleed for a longer time after an injury than you would if your blood clotted properly.

Question 31

Cystic Fibrosis

Answer 31

Mucus clogs lungs; liver and pancreas; victims usually don’t live to adulthood.

a genetic condition that affects a protein in the body. People who have cystic fibrosis have a faulty protein that affects the body’s cells, its tissues, and the glands that make mucus and sweat. Normal mucus is slippery and protects the airways, digestive tract, and other organs and tissues.

Question 32

How crossing over can affect the expected ratios (read section on Linkage groups on pages 222-223)

Answer 32

Crossing over causes the F2 generation to have many offspring with the recessive traits instead of lots with the dominant traits. This meant there had to be some kind of change for this to have occurred. This could have been caused by a mutation but that only happens in a small percentage of offspring and this happened in a large amount. The alleles became rearranged so recessive traits became more common.