chapter 9: dna and heredity

Question 0

transgenic

Answer 0

cells transformed by having dna pass through cell membrane (can inject new)

Question 1

bacteriophage

Answer 1

viruses that infect bacteria

Question 2

makeup of dna

Answer 2

nucleotides made up of deoxyribose, phosphate group, and nitrogen base

Question 3

helical

Answer 3

having a spiral shape

Question 4

anti-parallel

Answer 4

strands run in opposite directions

Question 5

base pairs

Answer 5

adenine with thymine

guanine and cystosine

Question 6

semiconservative replication

Answer 6

each strand of parental dna acts as template

Question 7

dna polymerase

Answer 7

catalyzes the addition of nucleotide, helping the chain grow

Question 8

primer

Answer 8

starter strand (often a short single strand of rna)

Question 9

primase

Answer 9

enzyme that synthesizes the primer one nucleotide at a time

Question 10

replication fork

Answer 10

dna and replication occurs in both directions around the circular chromosome

Question 11

leading strand

Answer 11

grows continuously as fork opens up

Question 12

lagging strand

Answer 12

synthesized in opposite direction, away from replication fork
synthesis is of discontinuous stretches

Question 13

okazaki fragments

Answer 13

discontinuous stretches of dna from the lagging strand

Question 14

dna ligase

Answer 14

links fragments to make the lagging strand whole

Question 15

processive

Answer 15

how polymerase works: continous, catalyzing many reactions at a time

Question 16

telomeres

Answer 16

useless repetative sequence at end of chromosomes to prevent joining

Question 17

telomerase

Answer 17

catalyzes the additiob of any lost telemeric sequences

Question 18

proofreading

Answer 18

dna polymerase recognizes mispairing of bases, removes them, and tries again

Question 19

mismatch repair

Answer 19

proteins look for mismatched base pairs after replication. if wrong, a portion of the dna is removed and replaced

Question 20

polymerase chain reaction

Answer 20

laboratory technique developed to understand replication

allows for dna amplification: making multiple copies of short dna sequences in test tubes

Question 21

somatic mutations

Answer 21

occur in somatic (body cells) and are passed on through mitosis
ex: patch of skin cells

Question 22

germline mutations

Answer 22

in cells that give rise to gametes, whill pass the mutation on at fertilization

Question 23

loss of function mutations

Answer 23

result in loss of gene expression or in the production of nonfunctional rna/protein

Question 24

gain of function mutations

Answer 24

leads to protein with altered function

common in cancer

Question 25

conditional mutations

Answer 25

cause phenotypes only infer restrictive conditions

ex: temperature sensitive

Question 26

point mutation

Answer 26

gain loss or substitution of single nucleotide

Question 27

chromosomal mutation

Answer 27

extensive changes in chromosomal structure

Question 28

mutagens

Answer 28

environmental substances that cause mutations, such as radiation or certain chemicals

Question 29

4 types of chromosomal mutations

Answer 29

1. deletions
2. duplications
3. inversions: breaking and rejoining
4. translocations: segments break and join diff chromosomes

Question 30

spontaneous duplication

Answer 30

without outside influence. a few are:

1. dna polymerase can make errors in replication
2. nucleotide bases have alternate structures that affect pairing
3. meiosis is not perf
4. gene sequences interrupted

Question 31

induced mutations

Answer 31

mutagen. examples:
1. chemicals add groups to bases
2. chemicals alter bases
3. radiatiob damages dna