Chapter 14: Human Heredity

Question 0

Karyotype

Answer 0

Micrograph of the complete diploid set of chromosomes grouped together in pairs, arranged in order of decreasing size

Question 1

Genome

Answer 1

An entire set of genetic information that an organism carries in its DNA

Question 2

Sex chromosomes

Answer 2

One of two chromosomes that determines an individual’s sex

Question 3

Barr body

Answer 3

A dense region in the nucleus of cells of a female human formed by one of the X-chromosomes deactivating and condensing

Question 4

Autosome

Answer 4

chromosome that is not a sex chromosome, also called an autosomal chromosome

Question 5

Sex-linked gene

Answer 5

Gene located on a sex chromosome

Question 6

Pedigree

Answer 6

Chart that shows the presence or absence according to the relationships within a family across several generations

Question 7

Nondisjunction

Answer 7

Error in meiosis in which homologous chromosomes fail to separate properly

Question 8

Sickle-Cell Disease

Answer 8

Genetic disorder caused by a a defective allele for beta-globin, one of two polypeptides in hemoglobin. This results in less-soluble hemoglobin, which causes hemoglobin molecules to stick together when the blood’s oxygen level decreases. The molecules clump into long fibers, forcing cells into a distinctive sickle shape. The rigid structure of a sickle-cell gets stuck in capillaries and can cause damage to cells, tissues, or organs.

Question 9

Cystic Fibrosis

Answer 9

Genetic disorder caused by the deletion of three bases in the gene for the protein called cystic fibrosis transmembrane conductance regulator (CFTR), which normally allows chlorine ions to pass through cell membranes. The loss of the three bases results in a loss of a single amino acid- phenylalanine- which causes the protein to fold improperly and then be destroyed. Therefore, cell membranes cannot transport chlorine ions, and tissues throughout the body malfunction. Cystic fibrosis is caused by a recessive allele: people with only one copy of the normal allele can produce enough CFTR for their cells to function properly.

Question 10

Huntington’s Disease

Answer 10

Genetic disorder caused by a dominant allele found for a protein in brain cells which contains a long string of bases in which the codon CAG- coding for the amino acid for glutamine- repeats over and over again. Symptoms including metal deterioration and uncontrollable movements do not usually appear until middle age.

Question 11

Turner’s Syndrome

Answer 11

Genetic disorder caused by the absence of one X chromosome in females

Question 12

Down Syndrome

Answer 12

Chromosomal disorder caused by non-disjunction when a child inheriting 3 copies of chromosome 21, causes mild to severe me tal retardation and birth defects

Question 13

Turner’s syndrome

Answer 13

Chromosomal disorder caused by non-disjunction when a woman inherits only one X chromosome, causes sterility

Question 14

Klinefelter’s Syndrome

Answer 14

Chromosomal disorder caused by non-disjunction when a man inherits an extra X chromosome, which causes problems in meiosis and sterility