Bio Chapter 12

Front 1

• Virulence

Back 1

the ability to cause disease in a host

Front 2

Griffith’s transformation experiment

Back 2

Can a genetic trait be transmitted from one bacterial strain to another?

Front 3

• Avery’s contribution to Griffith’s experiment

Back 3

A series of experiments in which the lysed (split open) S cells and separated the cell contents into several fractions: lipids, proteins, polysaccharides, and nucleic acids (DNA and RNA)

Front 4

• Transformation

Back 4

A type of permanent genetic change in which the properties of one strain of dead cells are conferred on a different strain of living cells

Front 5

Hershey-Chase experiments

Back 5

Is DNA or protein the genetic material in bacterial viruses (phages)?

Front 6

Bacteriophages

Back 6

viruses infect bacteria

Front 7

• Nucleotide

Back 7

DNA building block consisting of the pentose sugar deoxyribose, a phosphate, and 1 of 4 nitrogeneous bases

Front 8

(A)

Back 8

adenine

Front 9

(G),

Back 9

guanine

Front 10

(T)

Back 10

thymine

Front 11

(C)

Back 11

cytosine

Front 12

Phosphodiester linkage

Back 12

When nucleotides are linked by covalent bonds. The 3’ carbon of one sugar is bonded to the 5’ phosphate of the adjacent sugar to form a 3’ to 5’ linkage

Front 13

Chargaff’s rule

Back 13

the number of purines equals the numbers of pyrimidines. The number of adenines (A) equals the number of thymines (T) and the number of guanines (G) equals the number of cytosines (C)

Front 14

Double Helix

Back 14

The shape of DNA, consisting of 2 polynucleotide chains arranged in this way

Front 15

Antiparallel

Back 15

Because the two strands of DNA run in opposite directison, they are said to be antiparallel to one another

Front 16

DNA replication

Back 16

A chromosome becomes duplicated so that it consists of 2 identical sister chromatids that later separate at anaphase; the genetic material must be precisely duplicated and disturbed to the daughter cells

Front 17

Semiconservative replication

Back 17

Type of information copying. The result of DNA replication is 2 double helices, each identical to the original one and consisting of one original strand from the parent molecule and one newly synthesized complementary strand

Front 18

• Mutations

Back 18

Genetic changes

Front 19

Meselson-Stahl experiment

Back 19

What is the mechanism of DNA replication

Front 20

o Origins of replication

Back 20

DNA replication begins at specific sites on the DNA molecule

Front 21

o DNA helicases

Back 21

helix destabilizing enzymes that bind to DNA at the origin of replication and break hydrogen bonds, thereby separating the strands

Front 22

single-stranded binding (SSB) proteins

Back 22

bind to single DNA strands and stabilize then; this prevents the double helix from re-forming until the strands are replicated

Front 23

o Replication fork

Back 23

A Y-shaped structure where both DNA strands replicate at the same time at the junction between the separated strands

Front 24

o Topoisomerases

Back 24

enzymes that produce breaks in the DNA molecules and then rejoin strands, relieving strain and effectively preventing supercoiling and knot formation during replication

Front 25

5’ to 3’ direction

Back 25

• DNA synthesis always proceeds in

Front 26

o DNA polymerases

Back 26

The enzymes that catalyze the linking of successive nucleotide subunits

Front 27

o RNA primer

Back 27

a short piece of RNA is synthesized at the point where replication begins

Front 28

RNA

Back 28

a nucleic acid poymer consisting of nucleotide subunits that can associate by complementary base pairing with the single-strand DNA template.

Front 29

DNA primase

Back 29

synthesized to the RNA primer. Is an enzyme that starts a new strand of RNA opposite a short stretch of the DNA template strand.

Front 30

• Leading strand

Back 30

One of the 2 DNA polymerase molecules adds nucleotides to the 3’ end of the new strand that is always growing toward the replication fork. This strand is synthesized smoothly and continuously

Front 31

• Lagging Strand

Back 31

the other DNA polymerase molecule adds nucleotides to the 3’ end of the other new strand. This strand is always growing away from the replication fork. Thus, only short pieces can be synthesized

Front 32

• DNA ligase

Back 32

– an enzyme that links the 3’ hydroxyl of one okazaki fragment to the 5’ phosphate of the DNA immediately next to it, forming a phosphodiester linkage.

Front 33

• Mismatch repair

Back 33

Special enzymes recognize the incorrectly paired nucleotides and remove them; DNA polymerases then fill in the missing nucleotides

Front 34

• Nucleotide excision repair

Back 34

– One type of DNA repair which is commonly used to repair DNA lesions

Front 35

• Telomeres

Back 35

Protective end caps on chromosomes that do not contain protein-coding genes

Front 36

• Telomerase

Back 36

A special DNA replication enzyme can lengthen telomeric DNA by adding repetitive nucleotide sequences to the ends of eukaryotic chromosomes

Front 37

• Cell aging

Back 37

Research evidence suggets that the shortening of telomeres may contribute to this and various types of cancers