Chapter 16 Terms

Question 1

transformation

Answer 1

the delivery of DNA into a bacteria cell

Question 2

nucleotide

Answer 2

complementary DNA nucleotides are added to form two daughter DNA molecules

Question 3

nucleoside

Answer 3

Each nucleotide that is added to a growing DNA strand is a nucleoside triphosphate

Question 4

X-ray crystallography

Answer 4

American scientist James Watson examined the x-ray diffraction pattern and determined that the image is a result of a helical molecule
The X-ray images also enabled Watson to deduce the width of the helix and the spacing of the nitrogenous bases

Question 5

antiparallel

Answer 5

subunits run in opposite directions

Question 6

DNA replication

Answer 6

crucial step that must occur in order for DNA to be passed on to new generations of cell during cell division

Question 7

semiconservative replication

Answer 7

predicts that when a double helix replicates, each daughter molecule will have one old strand (derived or “conserved” from the parent molecule) and one newly made strand

Question 8

origins of replication

Answer 8

the site on the parental DNA where replication begins)

-Prokaryotes only have one origin of replication, while eukaryotes have hundreds to thousands

Question 9

DNA helicase

Answer 9

binds to the initiator proteins and begins separating double stranded DNA into single strands in a small area which forms a “replication bubble” and two replication “forks” at each side of the bubble

Question 10

single stranded binding proteins (SSB)

Answer 10

binds to and stabilize single-stranded DNA to make sure that the two strands remain separated

Question 11

topoisomerase

Answer 11

relaxes the tension of DNA from “over-winding” ahead of replication forks by breaking, swiveling, and rejoining DNA strands

Question 12

replication fork

Answer 12

formed in the replication bubble at each side of bubble

Question 13

primase

Answer 13

enzyme that DNA polymerase relies on its assistance
-adds a short RNA primer (8-10 RNA nucleotides complementary to DNA template) to the DNA template that forms a 3’ end for DNA polymerase to attach to and initiate replication from

Question 14

primer

Answer 14

8-10 RNA nucleotides complementary to DNA template

a new RNA primer must be added for each segment that is added to the template

Question 15

DNA polymerase

• DNA polymerase III
• DNA polymerase I

Answer 15

DNA polymerase is the enzyme responsible for adding the complementary DNA nucleotides to the two template strands

Question 16

deoxynucleotide triphosphate (dNTP)

Answer 16

DNA polymerase adds dNTPs to both strands of separated double stranded DNA in 5’ to 3’ direction

Question 17

leading strand

Answer 17

strand that allows for DNA polymerase to continuously add DNA nucleotides since it runs in the same direction as the replication fork

Question 18

lagging strand

Answer 18

strand only allows DNA polymerase to add nucleotides in the direction going away from the replication fork

Question 19

parental DNA strand

Answer 19

double stranded parental DNA with origin of replication(s)

Question 20

Okazaki fragments

Answer 20

short segments that result from the discontinuous addition of DNA nucleotides

Question 21

DNA ligase

Answer 21

Okazaki fragments are eventually connected together by DNA ligase to form a continuous strand

Question 22

Continuous replication vs non-continuous replication

Answer 22

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Question 23

Replication proofreading

Answer 23

newly made DNA are proofread by polymerases, replacing any incorrect nucleotides
-due to proofreading, the finished replicated DNA molecule has a much lower occurrence of mismatching (1 in every 10^10 nucleotides)

Question 24

histones

Answer 24

DNA packaging proteins

Nucleosomes consists of a core of 8 histones

Question 25

Nucleosomes

Answer 25

(10nm fibers)- consists of a core of eight histones (DNA packaging proteins) with DNA wound twice around which forms a 10nm fiber

Question 26

Heterochromatin

Answer 26

Type of chromatin:

During the cell cycle: highly compacted, relatively inactive form of chromatin (not highly transcribed)

Question 27

Euchromatin

Answer 27

During the cell cycle: Less compacted, relatively active form of chromatin (more highly transcribed)