Quiz 1

Question 1

genetic code

Answer 1

is the correspondence between mRNA codons and the 20 amino acids of life. It enables cells to construct proteins using DNA instructions that have been transcribed into RNA.

Question 2

Alternate splicing

Answer 2

cuts mRNA in different ways, forming slightly different combinations of exons for some genes.

Question 3

Introns

Answer 3

are sequences that are transcribed but then cut themselves out before exiting the nucleus. The protein-encoding exons of the mRNA join and are proofread.

Question 4

Transcription factors

Answer 4

are proteins that control which genes are transcribed in a cell under certain conditions by binding DNA in response to signals from outside the cell.

Question 5

DNA replication is semiconservative

Answer 5

in that the two parental strands separate and each is a template for assembling new daughter strands. Semiconservative means that each new DNA double helix conserves half of the parental one.

Question 6

complementary base pairs

Answer 6

with T and G with C. Hydrogen bonds hold the base pairs together.

Question 7

antiparallelism

Answer 7

The two polynucleotide chains run head-to-toe, based on the relative locations of the carbons in the sugars (5’ to 3’ and 3’ to 5’).

Question 8

nucleotide

Answer 8

A building block of DNA, which consists of one deoxyribose, one phosphate group, and one nitrogenous base.

Question 9

purine bases

Answer 9

adenine and guanine

Question 10

pyrimidine bases

Answer 10

cytosine and thymine

Question 11

gene pool

Answer 11

refers to all the alleles of a given population

Question 12

Pedigrees

Answer 12

are diagrams that depict the transmission of recessive and dominant traits through generations.

Question 13

Dominant alleles

Answer 13

are expressed when one copy is present

Question 14

Recessive alleles

Answer 14

require two copies for expression.

Question 15

genotype

Answer 15

is the allelic makeup of an individual

Question 16

phenotype

Answer 16

is the observable or measurable expression of an individual’s alleles (traits or health condition).

Question 17

stem cells

Answer 17

that “self-renew” as well as produce cells that specialize. These two properties are essential for growth, development, and healing.

Question 18

Mendelian trait

Answer 18

cause by a single gene

Question 19

multifactorial trait

Answer 19

is caused by one or more genes and environmental influences. Most genes do not function alone.

Question 20

karyotype

Answer 20

is a chart of an individual’s chromosomes.

Question 21

somatic cell

Answer 21

23 pairs of chromosomes, constituting two copies of the genome. Twenty-two pairs are autosomes and do not differ between the sexes, and one pair is the sex chromosomes. XX is female; XY is male.

Question 22

Chromosomes

Answer 22

consist of hundreds of genes

Question 23

alleles

Answer 23

arise by mutation, which can cause disease. A mutation also refers to a change in a gene.

Question 24

nitrogenous base pairs

Answer 24

adenine and thymine

guanine and cytosine