Chapter 3 - Genetics, Conception, and Prenatal Development

Question 1

Chromosomes

Answer 1

Physical structures of inheritance consisting of DNA and supporting proteins.

Question 2

Deoxyribonucleic Acid (DNA)

Answer 2

Molecules that carry genetic code of a cell

Question 3

Genes

Answer 3

Units of hereditary information; each gene is a segment of DNA in a specific location on a chromosome

Question 4

Mitosis

Answer 4

A lifelong process of nuclear division involving the replication of chromosomes and their distribution into two identical nuclei, usually followed by cell division.

Question 5

Sex chromosomes

Answer 5

The pair of sex-determining chromosomes that each human possesses: XX in females and XY in males.

Question 6

Autosomes

Answer 6

Any of the chromosomes other than the sex-determining chromosomes; also referred to as somatic chromosomes

Question 7

Meiosis

Answer 7

The cell division process in which pairs of chromosomes exchange pieces of genetic material, producing chromosomes with new combinations of genes and traits in offspring.

Question 8

Congenital

Answer 8

A characteristic or condition present from birth

Question 9

Sex-linked inheritance

Answer 9

Transmission of characteristics via a sex chromosome.

Question 10

Down Syndrome

Answer 10

A syndrome, also referred to as Trisomy 21, in which there is an extra chromosome 21, resulting in distinctive facial features and other physical characteristics and mild to severe cognitive disabilities

Question 11

Multifactorial Transmission

Answer 11

The interaction of genes and the environment that produces most complex human characteristics.

Question 12

Ovum

Answer 12

Female sex cell

Question 13

Sperm

Answer 13

Male sex cell

Question 14

Zygote

Answer 14

The cell that results when an ovum is fertilized by a sperm cell

Question 15

Monozygotic Twins

Answer 15

Siblings resulting from a single egg; also known as identical

Question 16

Dizygotic Twins

Answer 16

Siblings resulting from two different eggs, also known as fraternal

Question 17

Infertility

Answer 17

The absence of pregnancy after 12 months of unprotected sexual intercourse

Question 18

Assisted Reproductive Technology (ART)

Answer 18

Fertility treatments in which both egg and sperm are handled

Question 19

Germinal Stage

Answer 19

The first prenatal stage, beginning at conception and lasting approximately two weeks

Question 20

Blastocyst

Answer 20

A hollow, spherical structure composed of approximately 100 identical cells, which are formed through mitosis during the first week of conception.

Question 21

Embryo

Answer 21

The tern for a blastocyst that has become implanted in the uterine wall

Question 22

Embryonic Stage

Answer 22

The second prenatal stage, lasting from 2 to 8 weeks after conception

Question 23

Teratogens

Answer 23

Substances such as alcohol, drugs, nicotine, and radiation that are known to cause harm to the developing embryo and fetus

Question 24

Cephalocaudal Principle

Answer 24

The pattern of growth in which development begins in the head and occurs later in the tail of the organism

Question 25

Proximodistal Principle

Answer 25

The pattern of growth in which development begins in the center of the body and moves toward the extremities

Question 26

Placenta

Answer 26

A network of blood vessels, formed from cells in the trophoblast and in the uterine lining, which conveys oxygen and nutrients to the embryo and carries away waste products

Question 27

Umbilical Cord

Answer 27

The structure through which the embryo is connected to the placenta

Question 28

Ectoderm

Answer 28

The outer layer of the developing embryo, which becomes the brain and spinal cord; sensory organs; and skin, nails, hair, and teeth

Question 29

Mesoderm

Answer 29

The middle layer of the inner cell mass, from which the circulatory and excretory systems, muscles, and skeleton develop

Question 30

Endoderm

Answer 30

The inner layer of the inner cell mass, from which the respiratory and digestive systems develop.

Question 31

Fetal Stage

Answer 31

The third prenatal stage, lasting from 8 weeks until birth

Question 32

Neuron

Answer 32

Nerve cell in the brain, comprised of a cell body, axon(s)