chapter 2.1

Question 1

zygote

Answer 1

the new cell formed by the process of fertilization

Question 2

genes

Answer 2

the basic unit of genetic information

Question 3

DNA

Answer 3

the substance that genes are composed of that determines the nature of every cell in the body and how each will function

Question 4

chromosomes

Answer 4

rod shaped portions of dna that are organized in 23 pairs

Question 5

mitosis

Answer 5

the replication of most types of cells, nearly all the cells of the body will contain the same 46 chromosomes as the zygote

Question 6

meiosis

Answer 6

each gamete receives one of the two chromosomes that make up each of the 23 pairs

Question 7

monozygotic twins

Answer 7

twins produced by a single fertilized ovum

Question 8

dizygotic twins

Answer 8

twins who are produced when two separate ova are fertilized by two separate sperm at roughly the same time

Question 9

dominant trait

Answer 9

the one trait that is expressed when two competing traits are present

Question 10

recessive trait

Answer 10

a trait within an organism that is present, but is not expressed

Question 11

genotype

Answer 11

the underlying combination of genetic material present (but not outwardly visible) in an organism

Question 12

phenotype

Answer 12

an observable trait; the trait that actually is seen

Question 13

homozygous trait

Answer 13

inheriting from parents similar genes for a given trait

Question 14

heterozygous trait

Answer 14

inheriting from parents different forms of a gene for a given trait

Question 15

pku

Answer 15

an inherited disorder in which a child is unable to make use of phenylalanine, an essential amino acid present in proteins found in milk and other foods

Question 16

polygenic inheritance

Answer 16

inheritance in which a combination of multiple gene pairs is responsible for the production of a particular trait

Question 17

reaction range

Answer 17

the potential degree of variability in the expression of a trait due to environmental conditions

Question 18

x-linked genes

Answer 18

genes that are considered recessive and located only on the x chromosome

Question 19

behavioural genetics

Answer 19

studies the effects of heredity on behaviour

Question 20

spontaneous mutation

Answer 20

genes spontaneously change their form

Question 21

down’s syndrom

Answer 21

a disorder produced by the presence of an extra chromosome on the twenty-first pair; once referred to as mongolism

Question 22

fragile x syndrome

Answer 22

a disorder produced by injury to a gene on the x chromosome, producing mild to moderate intellectual impairment

Question 23

sickle-cell anemia

Answer 23

a blood disorder that gets its name from the shape of the red blood cells in those who have it

Question 24

tay-sachs disease

Answer 24

a disorder that produces blindness and muscle degeneration prior to death: there is no treatment

Question 25

klinefelter syndrome

Answer 25

a disorder resulting from the presence of an extra X chromosome; the syndrome produces underdeveloped genitals, extreme height, and enlarged breasts

Question 26

genetic counselling

Answer 26

the discipline that focuses on helping people deal with issues relating to inherited disorders

Question 27

karyotype

Answer 27

a chart containing enlarged photos of each of the chromosomes

Question 28

first trimester screen

Answer 28

combines a blood test and ultrasound sonography in the eleventh to thirteenth week of pregnancy and which can identify chromosomal abnormalities and other disorders such as heart problems

Question 29

ultrasound sonography

Answer 29

high frequency sound waves scan the mothers womb to produce an image of the unborn baby, whose size and shape can then be assessed

Question 30

chorionic villus sampling (CVS)

Answer 30

a test that involves taking samples of hairlike material that surround the embryo; used to find genetic defects

Question 31

amniocentesis

Answer 31

the process of identifying genetic defects by examining a small sample of fetal cells drawn by a needle inserted into the amniotic fluid surrounding the unborn fetus

Question 32

germ line therarpy

Answer 32

cells with defective genes are taken from an embryo, repaired and replaced

Question 33

temperament

Answer 33

patterns of arousal and emotionality that represent consistent and enduring characteristics in an individual

Question 34

multifactorial transmission

Answer 34

the determination of traits by a combination of both genetic and environmental factors in which a genotype provides a range within which a phenotype can be expressed

Question 35

do we inherit our personality

Answer 35

yes

Question 36

neuroticism

Answer 36

degree of emotional stability and individual characteristically displays

Question 37

extroversion

Answer 37

degree to which a person seeks to be with others, to behave in an outgoing manner , and generally to be sociable

Question 38

how do we know which personality traits reflect heredity?

Answer 38

some evidence comes from direct examination of genes themselves

Question 39

schizophrenia

Answer 39

genetic factors and run in families but not the sole cause

Question 40

disorders

Answer 40

heredity often produces a tendency toward a future course of development but when and whether the characteristic will be displayed depends on the environment

Question 41

three ways a childs genetic predisposition might influence his or her environment

Answer 41

• children tend to focus on aspects of their environment hat are most in tune with their genetic abilities
• the gene-environment influence might be more passive and less direct
• the genetically driven temperament of a child might evoke certain environmental influences