Chapter 4

Question 1

Polygenic traits

Answer 1

Traits that are influenced/ affected by two or more genes

Mainly influenced by environmental factors such as nutrition and exposure to sunlight

Ex: skin, eye, hair color

Question 2

Mendelian traits

Answer 2

Characteristics that are influenced by ONLY ONE allele/gene

Ex: bloody type, sickle-cell anemia

Question 3

Mendelian vs. polygenic traits

Answer 3

Mendelian influenced by ONE gene

Polygenic influenced by 2 or more genes

Question 4

Principle of Segregation

Answer 4

For any particular trait, the pair
of alleles of each parent
separate and only one allele
passes from each parent on to
an offspring

Question 5

Independent assortment

Answer 5

Genes are passed to offspring independently of each other

The inheritance of one trait does not affect the inheritance of another

Question 6

Phenotype

Answer 6

The observable, physical expression of genotypes

Question 7

Genotype

Answer 7

The genetic makeup of an individual

Refers to an organism’s entire genetic makeup or to the alleles at a particular locus

A, AB , O

Question 8

Gene pool

Answer 8

All the genes shared within a population

Question 9

Antigens

Answer 9

Molecules structures on the surface of red blood cells

• Any molecule that could become a target of the immune system response…

• Substances, such as bacteria, viruses, foreign blood cells, etc. that stimulate the immune
system’s antibody production

Question 10

Allele frequency

Answer 10

In a population, the percentage of all the alleles at a locus accounted for by one specific allele

Question 11

ABO blood group

Answer 11

Consists of 3 alleles

A,B,O

Homo: AA, BB, OO

Hetero: AO, BO

Codominance: AB

Question 12

Macro evolution

Answer 12

Changes produced only after many generations, such as the appearance of new species

Question 13

Micro evolution

Answer 13

Small changes occurring within species, such as changes in allele frequencies

Ex: skin pigment

Question 14

Natural selection

Answer 14

when some individuals of a population are better able
to adapt to their environment and, subsequently, produce more offspring.

• Selective agent: The environment

• Differential productive success between
individuals is the key.

produce more offspring means
greater influence on the gene frequencies of the next generation and are therefore “more fit”

Question 15

Genetic drift

Answer 15

The change in allele frequencies produced by random factors

Occurs more rapidly in small population size

Question 16

Founder effect

Answer 16

A type of genetic drift in which allele frequencies are altered by reproductively isolating a small segment of a population from a
larger population.

Causes the smaller population to
diverge genetically from the parent population

Question 17

Gene flow

Answer 17

Exchange of genes between populations

Question 18

Sickle cell trait

Answer 18

Heterozygous condition in which a person has one Hb^A allele and one Hb^s allele

They have some normal hemoglobin

Question 19

Sickle cell anemia

Answer 19

A severe inherited hemoglobin disorder in which red blood cells collapse when deprived of oxygen

Results from inheriting two copies of a mutant allele

Question 20

Mendel is known for?

Answer 20

He discovered the fundamental principles of how traits are inherited

Did not know about chromosomes