CH 16: The Molecular Basis of Inheritance

Question 1

nucleotide

Answer 1

a pentose sugar attached to a nitrogenous base and to a phosphate group.

Question 2

what are the 4 different nitrogenous bases in DNA?

Answer 2

Thymine, Adenine, Cytosine, and Guanine.

Question 3

Which two are single-ring pyrimidines?

Answer 3

Thymine and Cytosine

Question 4

Which two are double-ring purines?

Answer 4

Adenine and Guanine

Question 5

DNA is ___ and ___

Answer 5

antiparallel and complimentary

Question 6

Helicase

Answer 6

unwinds the two DNA strands at the origin of replication by temporarily breaking the hydrogen bonds. CREATES REPLICATION FORKS

Question 7

Single stranded binding proteins

Answer 7

binds to the newly separated DNA strands that were broken down by helicase to prevent them from re-forming the hydrogen bonds between them.

Question 8

Topoisomerase

Answer 8

relieves the overwinding in the DNA double strand caused by helicase’s unwinding the two strands.

Question 9

Primase

Answer 9

attaches a primer of RNA nucleotides that signal for DNA replication to begin at the location of the primer.

Question 10

DNA Polymerase III (3)

Answer 10

adds nucleotides to create new DNA strands using each separated strand as a template.DNA Polymerase III corrects most errors as they occur

Question 11

DNA Polymerase I (1)

Answer 11

replaces RNA nucleotide primers with DNA nucleotides.

Question 12

DNA Ligase

Answer 12

functions in the lagging strand to join the Okazaki fragments into one continuous DNA strand.

Question 13

DNA + histone =

Answer 13

nucleosome

Question 14

chromatin

Answer 14

DNA & proteins are organized as cylindrical fibers

Question 15

chromosomes are made up of

Answer 15

DNA and protein

Question 16

DNA is a polymer of

Answer 16

nucleotides

Question 17

there are _ different types of nucleotides

Answer 17

4

Question 18

A =

Answer 18

T

Question 19

G =

Answer 19

C

Question 20

in 1952,

Answer 20

Alfred Hershey and Martha Chase showed that DNA was responsible for genetic heredity

Question 21

___ is responsible for genetic heredity

Answer 21

DNA

Question 22

what accounts for all the genetic diversity on earth?

Answer 22

the order of the four (A,T, C, G) nucleotides

Question 23

what makes an organism what it is?

Answer 23

the combination and sequence of nucleotides in DNA provide the blueprint for making proteins that makes an organism what it is

Question 24

DNA Replication

Answer 24

the parent DNA strand unwinds and two new strands are created, using the base pairing rules. The result is two strands (sister chromatids) of DNA that each have one parent strand and one newly synthesized strand

Question 25

Prokaryote DNA is circular, ___

Answer 25

circular, round, and only have one replication origin. Replication proceeds in both directions

Question 26

Eukaryotic DNA (linear)

Answer 26

have many replication origins, replication proceeds in both directions

Question 27

new nucleotides can only be added to the __’ end of the new DNA strand that is being built

Answer 27

3’

Question 28

Nuclease

Answer 28

repairs DNA damage and synthesis errors. Example: when we get a sunburn, we hurt our DNA, nuclease goes in and pulls this error region in and DNA Polymerase III can fix it, and DNA Ligase seals the ends together.

Question 29

Mutations

Answer 29

can be passed down from one generation to the next. It is an error. Some can be harmful and some can be beneficial

Question 30

Telomeres

Answer 30

do NOT code for genes, they are short, repetitive nucleotide sequences.

Question 31

Telomerase

Answer 31

In ovary and teste cells, telomerase catalyzes the lengthening of telomeres so that genes are not lost. Good for germs cells, but not for somatic cells.

Question 32

The 5ꞌ end of a DNA strand always has a free __________ group while the 3ꞌ end always has a free __________ group.

Answer 32

phosphate, hydroxyl

Question 33

In DNA replication, the next nucleotide is incorporated into the growing polymer at the __________ of the molecule by an enzyme called __________.

Answer 33

3ꞌ (hydroxyl) end; DNA polymerase

Question 34

DNA polymerase adds nucleotides to the __________ of the leading strands, and to the __________ of the lagging strands (Okazaki fragments).

Answer 34

3’ end; 3’ end

Question 35

Replication of the lagging strand of DNA is accomplished by repeatedly making __________ followed by 1,000–2,000 nucleotide segments called __________.

Answer 35

short RNA primers; Okazaki fragments

Question 36

DNA and RNA are….

Answer 36

nucleic acids

Question 37

prokaryotic DNA is found in the

Answer 37

cytoplasm

Question 38

eukaryotic DNA is packed into the

Answer 38

nucleus of the cell