Chapter 6 Genetics, Conception, and Fetal Development VOCAB

Question 1

Alleles

Answer 1

An alternate form of a gene.

Question 2

Aneuploidy

Answer 2

An abnormal number of chromosomes.

Question 3

Cephalocaudal

Answer 3

Progression from head to toe (head-to-rump)

Question 4

Chromosomes

Answer 4

Threadlike packages of genes and other DNA in the nucleus of a cell.

Question 5

Diploid

Answer 5

Having a pair of chromosomes (46, or 23 pairs, in humans) that represents one copy of every chromosome from each parent; the number of chromosomes normally present in body cells other than gametes.

Question 6

Euploid cell

Answer 6

A cell with the correct or normal number of chromosomes within the cell.

Question 7

Gamete

Answer 7

Reproductive cell; in the female an ovum and in the male a spermatozoon.

Question 8

Genotype

Answer 8

Genetic makeup of an individual.

Question 9

Haploid

Answer 9

Having one copy of a chromosome from each pair (23 in humans, or half the diploid number). Gametes normally have a haploid number of chromosomes.

Question 10

Hematopoiesis

Answer 10

Production of blood cells; normally occurs in the bone marrow but may occur in extramedullary sites.

Question 11

Heterozygous

Answer 11

Having two different alleles for a genetic trait.

Question 12

Homologous

Answer 12

pairing at meiosis and having the same structural features and pattern of genes.

Question 13

Homozygous

Answer 13

Having two identical alleles for a genetic trait.

Question 14

Human genome

Answer 14

The complete set of genetic instructions in the nucleus of each human cell.

Question 15

Hydramnios

Answer 15

Excessive volume of amniotic fluid (more than 2000 ml at term). Also called polyhydramnios.

Question 16

Karyotype

Answer 16

A picture of a cell’s chromosomes, arranged from largest to smallest pairs.

Question 17

Lanugo

Answer 17

Fine, soft hair covering the fetus.

Question 18

Meiosis

Answer 18

Reduction cell division in gametes that halves the number of chromosomes in each cell.

Question 19

Mitosis

Answer 19

Cell division in body cells other than the gametes.

Question 20

Monosomy

Answer 20

Presence of only one of a chromosome pair in every body cell.

Question 21

Multiple-marker screening

Answer 21

Analysis of maternal serum for abnormal levels of alpha-fetoprotein, human chorionic gonadotropin, and estriols that may predict chromosomal abnormalities of the fetus; often called triple-screen or quad screen.

Addition of tests such as inhibin A have improved accuracy of the results, leading to alternate names for the package of tests.

Question 22

Mutation

Answer 22

Change in a gene that usually affects its function. Mutations may be in either the gametes or the somatic cells.

Question 23

Nuchal cord

Answer 23

Umbilical cord around the fetal neck.

Question 24

Oligohydramnios

Answer 24

Abnormally light or reduced menstruation.

Question 25

Oogenesis

Answer 25

Formation of gametes (ova) in the female.

Question 26

Phenotype

Answer 26

The outward expression of one's genetic makeup.

Question 27

Polyploidy

Answer 27

Having additional full sets of chromosomes

Question 28

Pseudomenstruation

Answer 28

Vaginal bleeding in the newborn, resulting from withdrawal of placental hormones.

Question 29

Sex chromosomes

Answer 29

The X or Y chromosome. Females have two X chromosomes; males have one X and one Y chromosome.

Question 30

Somatic cells

Answer 30

Body cells other than the gametes, or germ cells.

Question 31

Spermatogenesis

Answer 31

Formation of male gametes (sperm) in the testes.

Question 32

Translocation

Answer 32

Attachment of all or part of a chromosome to another chromosome.

Question 33

Trisomy

Answer 33

Presence of three copies of a chromosome in each body cell.

Question 34

Vernix caseosa

Answer 34

Thick, white substance that protects the skin of the fetus.

Question 35

Zygote

Answer 35

Cell formed by union of an ovum and sperm.