Chapter 13 Molecular Basis Of Inheritance

Question 1

In_______, Watson and Crick introduced a model for _______

Answer 1

1953, DNA

Question 2

Hereditary information is encoded in

Answer 2

DNA

Question 3

The role of DNA was worked out by studying_______ and the _______ that infected them

Answer 3

Bacteria, viruses

Question 4

Discovery of genetic of DNA began with research by _______ in _______

Answer 4

Frederick Griffith, 1928

Question 5

Griffith mixed heat heat killers remains of pathogenic strain with harmless strain and some living cells became pathogenic. He called this_____

Answer 5

Transformation

Question 6

Chargaff’s Rules

Answer 6

The base composition of DNA varies between species

In any species the percentages of A and T bases are equal and the percentages of G and C bases are equal

Question 7

Franklin used ______ to determine the molecular structure of DNA

Answer 7

X-ray crystallography

Question 8

Watson and Crick SemiConservative Model of Replication

Answer 8

Predicts that when a double helix replicates, each daughter molecule will have one old strand derived from the parent molecule and one newly made strand.

Question 9

Conservative model

Answer 9

Two parent strands rejoin

Question 10

Dispersive model

Answer 10

Each strand is a mix of old and new

Question 11

Replication begins at sites called _________, where the two DNA strands are separated, opening up a replication bubble

Answer 11

Origin of replication

Question 12

At each end of the bubble is a _________, a Y shaped region where the parents strands of DNA are being unwound

Answer 12

Replication fork

Question 13

Helicases

Answer 13

Are enzymes that untwist the double helix at the replication forks

Question 14

Single strand binding proteins

Answer 14

Bind to and stabilize single stranded DNA

Question 15

Topoisomerase

Answer 15

Relieves the strain caused by tight twisting ahead of the replication fork by breaking, swiveling, and rejoining DNA strands

Question 16

The initial strand is a short RNA

Answer 16

Primer

Question 17

DNA polymerase cannot initiate_______ of a polynucleotide, they can only add nucleotides to an already existing chain base paired with the template

Answer 17

Synthesis

Question 18

The enzyme_______, starts an RNA chain with a single RNA nucleotide and adds RNA nucleotides one at a time using the parent DNA as a template

Answer 18

Primase

Question 19

The new DNA strand will start from the

Answer 19

3’ end of the RNA primer

Question 20

Enzymes called_________, catalyze the elongation of new DNA at a replication fork

Answer 20

DNA polymerases

Question 21

The rate of elongation is about _____ nucleotides per second I’m bacteria and ______ per second in human cells

Answer 21

500,50

Question 22

dATP is

Answer 22

Used to make DNA and is similar to the ATP of energy metabolism

The difference is in the sugars: dATP has deoxyribose and ATP has ribose

Question 23

As each monomer nucleotide joins the DNA strand,

Answer 23

It loses two phosphate groups as a molecule of pyrophosphate

Question 24

Newly formed DNA strands must be formed _______ to the template strand

Answer 24

Antiparallel

Question 25

DNA polymerase add nucleotides only in the free 3’ end of a growing strand. Therefore a new DNA strand can only elongate in the

Answer 25

5’ to 3’ direction

Question 26

Leading strand

Answer 26

DNA polymerase synthesizes moving toward the replication fork

Question 27

To elongate the other new strand, the ___________, DNA polymerase must work in the direction away from the replication fork

Answer 27

Lagging strand

Question 28

The lagging strand is synthesized as a series of segments called

Answer 28

Okazaki fragments

Question 29

After formation of Okazaki fragments, DNA polymerase removes

Answer 29

The RNA primers and replaces the nucleotides with DNA

Question 30

The remaining gaps are joined together by

Answer 30

DNA ligase

Question 31

The proteins that participate in DNA replication form a large complex

Answer 31

DNA replication machine

Question 32

__________ proofread newly made DNA, replacing any incorrect nucleotides

Answer 32

DNA polymerase

Question 33

In________ of DNA, other enzymes correct errors in base pairing

Answer 33

Mismatch repair

Question 34

For linear DNA, the usual replication machinery cannot complete

Answer 34

The 5’ ends of daughter strands

Question 35

Repeated rounds of replication produce shorter DNA molecules with

Answer 35

Uneven ends

Question 36

Eukaryotic chromosomal DNA molecules have special nucleotide sequences at their ends called

Answer 36

Telomeres

Question 37

Telomeres typically consist of

Answer 37

Multiple repetitions of one short nucleotide sequence Telomeres do not prevent the shortening of DNA molecules but they do postpone it

Question 38

An enzyme called_________ catalyzes the lengthening of telomeres in __________

Answer 38

Telomerase, germ cells

Question 39

Telomerase is not active in most

Answer 39

Human somatic cells

Question 40

In a bacterium, the DNA is supercoiled and found in a region of the cell called the

Answer 40

Nucleoid

Question 41

A complex of DNA and protein found in the nucleus of eukaryotic cells

Answer 41

Chromatin

Question 42

Proteins called________ are responsible for the first level of DNA packing in ________

Answer 42

Histones, chromatin

Question 43

Four common types of histones

Answer 43

H2A, H2B, H3 and H4

Question 44

A__________ consists of DNA wound twice around a protein core of eight histones, two of each of the main histone types

Answer 44

Nucleosome

Question 45

The condensed chromatin is called___________, leas compacted chromatin is called

Answer 45

Heterochromatin, euchromatin

Question 46

Nucleic Acid Hybridization

Answer 46

The base pairing of one strand of a nucleic Acid to another complementary sequence

Question 47

Genetic Engineering

Answer 47

The direct manipulation of genes for practical purposes

Question 48

Plasmids

Answer 48

Small circular DNA molecules that replicate separately from the bacterial chromosome

Question 49

Recombinant DNA

Answer 49

Result of inserting foreign DNA into a plasmid

Question 50

Production of multiple copies of a single gene

Answer 50

Gene cloning

Question 51

The plasmid that carries the cloned DNA is called

Answer 51

Cloning vector

Question 52

Bacterial Restriction Enzymes

Answer 52

Cut DNA molecules at specific DNA sequences called restriction sites

Question 53

A restriction enzyme usually makes many cuts yielding

Answer 53

Restriction fragments

Question 54

Sticky ends

Answer 54

Cleaves DNA in a staggered manner. Sticky ends can bind with other complementary sticky ends

Question 55

Gel electrophoresis

Answer 55

Separates a mixture of nucleic Acid fragments based on length

Question 56

Polymerase Chain Reaction

Answer 56

Can produce many copies of a specific target segment of DNA

Question 57

The key to Polymerase Chain Reaction is an unusual heat stable DNA polymerase called

Answer 57

Taq Polymerase

Question 58

Once a gene is cloned, complementary base pairing can be used to determine the genes complete nucleotide sequence in a process called

Answer 58

DNA sequencing

Question 59

Purines

Answer 59

Two carbon nitrogen ring bases Adenine and Guanine

Question 60

Pyrimidines

Answer 60

One carbon nitrogen ring bases Thymine and Cytosine