Chapter 3

Question 0

Chromosomes

Answer 0

Molecules of DNA

Question 1

DNA

Answer 1

Molecule that contains the chemical instructions for cells to manufacture various proteins: promotes growth & sustains life.

Question 2

Allele

Answer 2

A variation that makes a gene different in some way from other genes for the same characteristics.

Question 3

Genome

Answer 3

The full set of genes that are the instructions to make an individual member of a certain species.

Question 4

Genotype

Answer 4

An organism’s genetic inheritance or genetic potential.

Question 5

Homozygous

Answer 5

Two genes of one pair that are exactly the same in every letter of their code.

Question 6

Heterozygous

Answer 6

Two genes of one pair that differ in some way.

Question 7

Zygote

Answer 7

Two gametes come together (1 sperm, 1 ovum)

Question 8

Stem cells

Answer 8

From which any other specialized type of cell can form into one kind of cell.

Question 9

Monozygotic (identical) twins

Answer 9

Originate from one zygote that splits very early in development and have the same genotype.

Question 10

Dizygotic (fraternal) twins

Answer 10

Result from fertilization of two separate ova by two separate sperm.

Question 11

Phenotype

Answer 11

The observable characteristics of a person including appearance personality intelligence and all other traits.

Question 12

Polygenic traits

Answer 12

Every trait is affected by many genes

Question 13

Multifactorial traits

Answer 13

Almost every trait is influenced by many factors.

Question 14

Additive traits

Answer 14

Height is affected by the contributions of about 100 genes.

Question 15

Dominant genes

Answer 15

Completely controls the phenotype with no noticeable effect of recessive genes.

Question 16

Carrier

Answer 16

A person whose genotype includes a gene that is not expressed in the phenotype

Question 17

X-linked

Answer 17

A gene carried on the X chromosome.

Question 18

Heritability

Answer 18

Statistical term that indicates what portion of the variation in a particular trait within a particular population is inherited. Environment can affect expression of these genes.

Question 19

Down syndrome

Answer 19

Three copies of chromosome 21

Question 20

Genetic counseling

Answer 20

Consultation and testing by trained professionals

Question 21

Phenylketonuria

Answer 21

Recessive condition results in inability to mobilize phenylalanine and can cause brain damage mental retardation and other symptoms.