2ND LE

Question 1

What is the order of linked genes A, B, and C?

Answer 1

The order of these genes on the chromosome is B-A-C.

Question 2

What is a trait caused by an environmental influence that appears to be inherited called?

Answer 2

A trait caused by an environmental influence that appears to be inherited is called a phenocopy.

Question 3

How many genes does the human mitochondrial genome consist of?

Answer 3

The human mitochondrial genome consists of 37 genes (that encode 13 proteins, 22 tRNAs, and 2 rRNAs).

Question 4

What gene controls X inactivation?

Answer 4

X inactivation is controlled by the XIST gene.

Question 5

What is the probability that June transmits colorblindness and ichthyosis to his son?

Answer 5

The probability that he transmits both traits to his son is 0% (sons inherit X-chromosome from the mother).

Question 6

What are acridine dyes?

Answer 6

Acridine dyes are mutagens that disrupt the reading frame of the gene.

Question 7

What is the characteristic shape of the mathematical plot for a multifactorial, polygenic trait?

Answer 7

The characteristic shape is a bell-shaped curve.

Question 8

What are traditional ways of evaluating multifactorial traits?

Answer 8

Traditional ways include empiric risk and heritability.

Question 9

What are DNA sequences that contribute to polygenic traits called?

Answer 9

They are called quantitative trait loci (QTLs).

Question 10

What are endorphins in relation to opiates?

Answer 10

Endorphins are the human equivalent of opiates.

Question 11

Which neurotransmitters might contribute to causing autism if levels are abnormal?

Answer 11

Serotonin and GABA.

Question 12

What does schizophrenia mean?

Answer 12

Schizophrenia means ‘split mind.’

Question 13

What may a person with narcolepsy experience?

Answer 13

A person with narcolepsy may experience cataplexy in which he or she suddenly collapses.

Question 14

What does it indicate if a cancer cell develops tumors in a healthy mouse?

Answer 14

This experiment indicates that cancer is heritable/transplantable.

Question 15

Where do mutational hot spots occur most often?

Answer 15

They occur most often in regions where the DNA is repetitive/symmetrical.

Question 16

What was the first single-gene disorder for which the mechanism of mutation was understood?

Answer 16

The first single-gene disorder was sickle cell disease.

Question 17

What term describes cancer cells that have lost their specializations?

Answer 17

The term is dedifferentiation/dedifferentiated.

Question 18

What is a passenger mutation?

Answer 18

A passenger mutation does not cause or propel a cancer’s growth and spread.

Question 19

What are genes that normally prevent cell division called?

Answer 19

They are known as tumor suppressor genes.

Question 20

What causes osteogenesis imperfecta?

Answer 20

It is caused by a mutation in a gene that encodes collagen.

Question 21

What arrangement do two linked genes in a heterozygote have?

Answer 21

The genes are said to be in a cis arrangement.

Question 22

What does genetic heterogeneity refer to?

Answer 22

Genetic heterogeneity refers to mutations in different genes that cause the same symptoms.

Question 23

What does a missense mutation do?

Answer 23

A missense mutation causes sickle cell disease by altering the protein’s shape and affecting its gene copies.

Question 24

How is a mitochondrial trait passed?

Answer 24

A mitochondrial trait is passed from mothers to sons.

Question 25

What affects the phenotype in imprinting?

Answer 25

Imprinting affects the phenotype when one allele is imprinted and the other is activated.

Question 26

What can cause mutation during meiosis?

Answer 26

Direct repeats can cause mutation when homologs duplicate during meiosis.

Question 27

How are genes on the X chromosome expressed in human males?

Answer 27

In human males, genes on the X chromosome are expressed.

Question 28

How many genes affect skin, hair, and eye color in humans?

Answer 28

There are more than 10 genes that affect skin, hair, and eye color in humans (nearly 170 genes).

Question 29

Do people with light skin have the same number of melanocytes as those with dark skin?

Answer 29

People with light skin have about the same number of melanocytes as people with very dark skin.

Question 30

What type of mutation changes GAA to UAA?

Answer 30

A mutation that changes the codon GAA to UAA is a nonsense mutation.

Question 31

Where was the first narcolepsy gene discovered?

Answer 31

The first narcolepsy gene was discovered in dogs (canines).

Question 32

What does GGG exhibit when consuming more cocaine for the same effect?

Answer 32

He is exhibiting tolerance.

Question 33

What worsens myotonic dystrophy with each generation?

Answer 33

It worsens because of the increasing number of repeated long DNA sequences.

Question 34

What do all cancers reflect at a general level?

Answer 34

All cancers reflect a defect in DNA repair and cell cycle regulation.

Question 35

What do sporadic cancers result from?

Answer 35

Sporadic cancers result from somatic cells (somatic mutations).

Question 36

What are traditional cancer treatments?

Answer 36

Traditional cancer treatments include surgery, chemotherapy, and radiation.

Question 37

Why are mutations more likely to occur in repeated DNA sequences?

Answer 37

Because the bases in the strand can form base pairs by generating loops that interfere with transcription and enzyme repair.

Question 38

What is a tautomer?

Answer 38

A tautomer is an alternate structure of a molecule.

Question 39

What is the proportion of shared genes between a grandparent and grandchild?

Answer 39

The proportion is 25 percent.

Question 40

What is a source of gamma radiation?

Answer 40

A source of gamma radiation is cesium isotope.