Chapter 3

Question 1

Fertilization

Answer 1

union of sperm and ovum to produce a zygote, also called conception

Question 2

Zygote

Answer 2

one-celled organism resulting from fertilization – a zygote has 23 chromosomes from mother and 23 chromosomes from father = 46 in all

Question 3

Ovulation

Answer 3

the rupture of a mature follicle and expulsion of the ovum

Question 4

Cervix

Answer 4

the opening of the uterus

Question 5

Assisted Reproductive Technologies (ART)

Answer 5

conception through artificial means; has a 23.6% success rate, very expensive

Question 6

Dizygotic Twins

Answer 6

twins conceived by the union of two different ova (or a single ovum that has split) with two different sperm cells; also called fraternal twins; not more alike genetically than other siblings

Question 7

Monozygotic Twins

Answer 7

Twins resulting from the division of a single zygote after fertilization; also called identical twins; genetically similar

Question 8

Heredity

Answer 8

the genetic transmission of heritable characteristics from parents to offspring

Question 9

Deoxyribonucleic Acid (DNA)

Answer 9

chemical that carries inherited instructions for the development of all cellular forms of life

Question 10

Chromosomes

Answer 10

coils of DNA that consist of genes – every cell except sperm and ova has 23 pairs of chromosomes

Question 11

Genes

Answer 11

small segments of DNA located in definite positions on particular chromosomes

Question 12

Mutations

Answer 12

permanent alterations in genes or chromosomes that may produce harmful characteristics

Question 13

X Chromosomes

Answer 13

chromosomes containing the genes for femaleness

Question 14

Y Chromosomes

Answer 14

chromosomes containing the genes for maleness

Question 15

Dominant Inheritance

Answer 15

hereditary characteristic that is expressed by an organism

Question 16

Recessive Inheritance

Answer 16

hereditary characteristic that is carried by an organism that does not express or show it

Question 17

Homozygous

Answer 17

possessing two identical alleles for a trait

Question 18

Heterozygous

Answer 18

possessing differing alleles for a trait

Question 19

Phenotype

Answer 19

observable characteristics of a person

Question 20

Genotype

Answer 20

genetic makeup of a person, containing both expressed and unexpressed characteristics

Question 21

Sex-linked Inheritance of Defects

Answer 21

pattern of inheritance in which certain characteristics carried on the X chromosome inherited from the mother are transmitted differently to her male and female offspring

Question 22

Heritability

Answer 22

statistical estimate of contribution of heredity to individual differences in a specific trait within a given population

Question 23

Reaction Range

Answer 23

potential variability, depending on environmental conditions, in the expression of a hereditary trait

Question 24

Cephalocaudal Principle

Answer 24

the upper parts of the body develop before the lower parts of the trunk

Question 25

Proximodistal Principle

Answer 25

The parts of the body near the center develop before the extremeties

Question 26

Germinal Stage

Answer 26

first two weeks of prenatal developed, characterized by rapid cell division, blastocyst formation, and implantation in the wall of the uterus

Question 27

Amniotic Sac

Answer 27

fluid-filled membrane that encases the developing baby, protecting it and giving it room to move

Question 28

Placenta

Answer 28

organ that allows, oxygen, nourishment, and wastes to pass between mother and embryo

Question 29

Umbilical Cord

Answer 29

Cord that connects the placenta to the baby and vice versa

Question 30

Embryonic Stage

Answer 30

second stage of gestation (2-8 weeks), characterized by rapid growth and development of major body systems and organs

Question 31

Trimester

Answer 31

a three-month period of pregnancy

Question 32

Spontaneous Abortion

Answer 32

natural expulsion of the uterus of an embryo that cannot survive outside the womb; also called a miscarriage

Question 33

Stillborn

Answer 33

term for a baby that is born dead after at least 20 weeks' gestation

Question 34

Fetal Stage

Answer 34

final stage of gestation (from 8 weeks to birth), characterized by increased differentiation of body parts and greatly enlarged body size

Question 35

Ultrasound

Answer 35

prenatal medical prodecure using high-frequency sound waves to detect the outline of a fetus and its movements, so as to determine whether a pregnancy is progressing normally

Question 36

Teratogen

Answer 36

environmental agent, such as a virus, a drug, or radiation, that can interfere with normal prenatal development and cause developmental abnormalities