Chaper 14 - Human Chromosomes

Question 0

when are the chromosomes studied?

Answer 0

the chromosomes are studied during mitosis, when they are fully condensed.

Question 1

what is a human genome? where is it carried?

Answer 1

a human genome is a full set of genetic information. it is carried in the DNA.

Question 2

what is a karyotype?

Answer 2

a karyotype is a picture of the complete set of chromosomes, grouped in pairs an arranged from biggest to smallest.

Question 3

how many chromosomes do humans have?

Answer 3

humans have 46 pairs of chromosomes, or two sets of 23.

Question 4

what are the sex chromosomes? how many are there?

Answer 4

the sex chromosomes are the chromosomes that determine an individual’s sex. There are 2 sex chromosomes.

Question 5

what are the sex chromosomes for female? and for male?

Answer 5

Female: XX
Male: XY

Question 6

what are the autosomal chromosomes?

Answer 6

the res of the chromosomes that are not sex chromosomes (44 in total) are the autosomal chromosomes.

Question 7

what gene helps determine skin and hair color?

Answer 7

the MC1R determines skin and hair color.

dominant: dark hair.
recessive: red hair.

Question 8

what is a sex linked gene? what does it determine?

Answer 8

a sex linked gene is a gene that is located on the sex chromosome and usually determines

Question 9

what chromosome carries man related traits only?

Answer 9

the Y chromosome.

Question 10

what is a Barr body? why is it formed?

Answer 10

the barr body is a dense region in the nucleus that is formed when genes in one of the X chromosomes randomly switch off.

Question 11

what is a pedigree?

Answer 11

a pedigree is a chart that shows the relationships within a family used to analyze the pattern of inheritance followed by a particular trait.

Question 12

what can a pedigree tell you?

Answer 12

a pedigree can tell you if an allele for a trait is dominant or recessive, autosomal or sex linked.

Question 13

how do molecules affect phenotypes?

Answer 13

there is a molecular basis for genetic disorders.

Question 14

what is the cause sickle cell disease? what is the consequence?

Answer 14

a disorder caused by a defective allele for beta-globin. The blood cells become more rigid and they get stuck in the capillaries.

Question 15

what is the cause of cystic fibrosis? what is the consequence? is it recessive or dominant?

Answer 15

CF is caused by the deletion of three genetic bases in the gene for a protein called CFTR. The protein is folded improperly and is destroyed.

Question 16

what is the cause of huntington’s disease? what is the consequence?

Answer 16

HD is caused by a dominant allele for a protein found in brain cells. the consequence is that the CAG repeats more that 40 times.

Question 17

what causes chromosomal disorder? what are the consequences?

Answer 17

chromosomal disorders are caused by nondisjunction, a common error in meiosis where homologous chromosomes fail to separate. it can result in a disorder of chromosome numbers.

Question 18

what are some chromosomal disorders?

Answer 18

Chromosomal disorders include
down syndrome
Turner’s syndrome
Klinefelter’s syndrome