Chapter 3 -- Genetics and Heredity

Question 1

Genotype

Answer 1

Total genetic endowment inherited by an individual

Question 2

Phenotype

Answer 2

Observable and measurable characteristics and traits of an individual; a product of the interaction of the genotype with the individual

Question 3

Gene

Answer 3

Large segment of nucleotides within a chromosome that codes for the production of proteins and enzymes. These proteins and enzymes underlie traits and characteristics inherited from one generation to the next

Question 4

Allele

Answer 4

Alternative form of a specific gene; provides a genetic basis for many individual differences

Question 5

Gamete

Answer 5

Sperm cells in males, egg cells in females, normally containing only 23 chromosomes

Question 6

Chromosome

Answer 6

Threadlike structure of DNA, located in the nucleus of cells, which forms a collection of genes. A human body cell normally contains forty-six chromosomes

Question 7

Human Genome

Answer 7

Entire inventory of nucleotide base pairs that compose the genes and chromosomes of humans

Question 8

DNA

Answer 8

Long, spiral staircase-like sequence of molecules created by nucleotides identified with the blueprint for for genetic inheritance

Question 9

Karyotype

Answer 9

Pictorial representation of an individual’s chromosomes

Question 10

Autosomes

Answer 10

One of 22 pairs of homologous chromosomes. The two members of each pair are similar in size, shape, and genetic function. The two sex chromosomes are excluded from this class

Question 11

X Chromosome

Answer 11

Larger of the two sex chromosomes associated with genetic determination of sex. Normally females have two X chromosomes and males, only one.

Question 12

Y Chromosome

Answer 12

Smaller of the two sex chromosomes associated with genetic determination of sex. Normally males have one Y chromosome and females, none

Question 13

Homozygous

Answer 13

Genotype in which two alleles of a gene are identical, thus having the same effects on a trait

Question 14

Heterozygous

Answer 14

Genotype in which two alleles of a gene are different. The effects on a trait will depend on how the two alleles interact.

Question 15

Dominant Allele

Answer 15

Allele whose characteristics are reflected in the phenotype even when part of a heterozygous genotype. Its genetic characteristics tend to mask the characteristics of other alleles

Question 16

Recessive Allele

Answer 16

Allele whose characteristics do not tend to be expressed when part of a heterozygous genotype. Its genetic characteristics tend to be masked by other alleles.

Question 17

Polygenic

Answer 17

Phenotypic characteristic influenced by two or more genes

Question 18

Epigenetics

Answer 18

The field of study concerned with how environmental factors interact with DNA and its transcription into mRNA to influence cell functioning and the phenotype

Question 19

Williams Syndrome

Answer 19

Dominant genetic disorder involving the deletion of a set of genes, which results in affected individuals’ typically having a strong social orientation, good musical ability, and some unusual linguistic capabilities accompanied by intellectual impairment and severe deficits in numerical and spatial ability.

Question 20

Sickle Cell Disease

Answer 20

Genetic blood disorder common in regions of Africa and other areas where malaria is found among descendants of the people of these regions. Abnormal blood cells carry insufficient oxygen.

Question 21

Phenylketonuria

Answer 21

Recessive genetic disorder in which phenylalanine, an amino acid, fails to be metabolized. Unless dietary changes are made to reduce intake of phenylalanine, sever intellectual impairment occurs

Question 22

Fragile X Syndrome

Answer 22

disorder associated with a pinched region of the X chromosome; a leading genetic cause of intellectual impairment in males

Question 23

Down Syndrome/ Trisomy X

Answer 23

Disorder resulting from extra chromosomal material on pari number twenty one; associated with intellectual impairment and distinct physical features

Question 24

Amniocentesis

Answer 24

method of sampling the fluid surrounding the developing fetus through insertion of a needle; used to diagnose fetal genetic and developmental disorders

Question 25

Chorionic Villus Sampling

Answer 25

method of sampling fetal chorionic cells; used to diagnose embryonic genetic and developmental disorders

Question 26

Fetal Blood Sampling

Answer 26

method of withdrawing blood from the umbilical cord of the fetus; used to diagnose genetic disorders, especially those that affect the blood

Question 27

Maternal Blood Screening

Answer 27

tests performed on a woman’s blood to determine whether the fetus she is carrying has an increased risk for some types of chromosomal and metabolic disorders

Question 28

Ultrasonography

Answer 28

method of using sound wave reflections to obtain a representation of the developing fetus; used to estimate gestational age and detect fetal abnormalities

Question 29

Behavior Genetics

Answer 29

study of how characteristics and behaviors of individuals, such as intelligence and personality, are influenced by the interaction between genotype and experience

Question 30

Heritability

Answer 30

proportion of variability in the phenotype that is estimated to be accounted for by genetic influences within a known environmental range

Question 31

Concordance Rate

Answer 31

percentage of pairs of twins in which both members have a specific trait identified in one twin