Ch 6: DNA and Biotechnology

Question 1

Nucleosides

Answer 1

contain a 5-carbon sugar bound to a nitrogenous base

Question 2

nucleotides

Answer 2

nucleosides w 1-3 phosphate groups added

Question 3

___ in DNA contain deoxyribose and in RNA contain ribose

Answer 3

nucleotides

Question 4

Nucleotides are abbrev A,C,G,T,U

Answer 4

adenine
cytosine
guanine
thymine
uracil

Question 5

Watson-Crick model says backbone of DNA is

Answer 5

organized alternating sugar and phosphate groups and is always read 5-3’

Question 6

purines

Answer 6

A and G

Question 7

pyrimidines

Answer 7

C,U,T

Question 8

A pairs with

Answer 8

T or U

Question 9

G three hydro bond with

Answer 9

C

Question 10

purine and pyrimidines are biologically aromatic heterocycles meaning

Answer 10

aromatic - cyclic, planar, conjugated, 4n+2pi electrons (Huckels rule where n needs to come out 0 or positive even integer when set equation equal to numb pi electrons in molecule)

heterocycles - ring structure that contains at least two different element in the ring

Question 11

Chargaff’s rule

Answer 11

purines and pyrimidines are equal in number in a DNA molecule and that because of base pairing the amount of adenine equals the amount of thymine,and C=G

Question 12

most DNA is ___ which forms righ handed helix

Answer 12

B-DNA

Question 13

low concentrations of DNA are in ___ with a zig zag shape, may be seen with hgih GC-content or high salt concentration

Answer 13

Z-DNA

Question 14

What can denature DNA and then allow it to reanneal when gone

Answer 14

heat, alkaline pH, chemicals like formaldehyde and urea can cause denaturation of DNA

Question 15

DNA organized into ___ chromosomes in the human cells

Answer 15

46

Question 16

in eukaryotes, DNA is wound around ____ to form ____ which may be stabilized by another ____

Answer 16

histone proteins (H2A, H2B, H3, H4)
nucleosomes
histone protein (H1)

Question 17

DNA and its associated histones as a whole make up ____ in the nucleus

Answer 17

chromatin

Question 18

heterochromatin

Answer 18

dense, transcriptionally active DNA that appears dark under the light microscopy

Question 19

euchromatin

Answer 19

less dense, transcriptionally active DNA that appears light under the light microscopy

Question 20

telomeres

Answer 20

end of chromosomes; high GC content to prevent unraveling of DNA

during replication, telomeres are slightly shortene. although this can partially be reversed by the enzyme telomerase

Question 21

centromeres

Answer 21

located in the middle of chromosomes and hold sister chromatids together until they are seperated during anaphase in mitosis. they also contain a high GC content to maintain a strong bond between chromatids

Question 22

replisome (replication complex)

Answer 22

is a set of specialized proteins that assist the DNA polymerases

Question 23

Origin of replication

Answer 23

when DNA is replicated it is unwound here by helicases
this produces two replication forks on either side of the origin

prokaryotes - circular chromosome with one OOR
eukaryotes - linear chromosome with many origin of replication

Question 24

unwound strands are kept from reannealing or being degraded by

Answer 24

single-stranded DNA-binding proteins

Question 25

__causes torisonal strain on the DNA molecule, which can be released by ____, which creates nicks in the DNA molecule

Answer 25

supercoiling | DNA topoisomerase II (DNA gyrase)

Question 26

DNA replication is ___ for one old parent strand and one new daughter strand are incorporated into each of the two new DNA molecules

Answer 26

semiconservative

Question 27

DNA cannot be synthesized without ____ so a small RNA primer is put down by ____

Answer 27

an adjacent nucleotide to hook onto primase

Question 28

DNA polymerase 3 (prokaryotes) or DNA polymerase alpha and gamma (eukaryotes)

Answer 28

can then synthesize a new strand of DNA read DNA temple 3 -5' and synthesize new strand 5-3

Question 29

leading strand needs only

Answer 29

one primer and can by synthesized continuously

Question 30

lagging strand needs

Answer 30

many primers and synthesized in sections called Okazaki fragments

Question 31

RNA primers can be removed later by ____ and filled in with DNA by _____

Answer 31

DNA polymerase 1 (prok) or RNase H (euk) DNA polymerase 1 (prok) or DNA polymerase gamma (euk)

Question 32

DNA ligase

Answer 32

can fuse the DNA strands together to create one complete molecule

Question 33

Oncogenes

Answer 33

develop from mutations of proto-oncogenes and promote cell cycling. they may lead to cancer which is unchecked cell proliferation with the ability to spread by local invasion or metastasize

Question 34

Tumor suppressor genes

Answer 34

code for proteins that reduce cell cycling or promote DNA repair

Question 35

during replication, _____ proofreads its work. the ____ is identified by its lack of ____ and corrects accordingly

Answer 35

DNA polymerase daughter strand methylation

Question 36

Mismatch repair also occurs during ___ of the cell cycle and uses genes MSH2 and MLH1

Answer 36

G2

Question 37

Nucleotide excision repair fixes

Answer 37

helix-deforming lesions of DNA (such as thymine dimers) via a cut-and-patch process that requires an excision endonuclease

Question 38

Base excision repair fixes

Answer 38

nondeforming lesions of the DNA helix (such as cytosine deamination) by removing the base, leaving an apurinic/apyrimidinic (AP) site. An AP endonuclease then removes the damaged sequence which can be filled in with the correct bases

Question 39

Recombinant DNA is

Answer 39

DNA composed of nucleotides from two different sources

Question 40

DNA cloning introduces a fragment of DNA into a

Answer 40

vector plasmid

Question 41

building of the cloning, ____ cuts both the plasmid and the fragment, which are left with sticky ends. once a fragment binds to the plasmid, it can be introduced into a bacterial cell and permitted to replicate, generating many copies of the fragment of interest

Answer 41

Restriction enzyme

Question 42

vectors contain

Answer 42

OOR, fragment of interest, one gene of antibodic resistance to permit for selection of that colony after replication once replicated bacterial cells can be used to create a protein of interest or can be lysed to allow for isolation of the fragment of interest from the vector

Question 43

DNA libraries

Answer 43

large collections of known DNA sequences genonmic and cDNA libraries are two examples

Question 44

Genomic libraries

Answer 44

contain large fragments of DNA including both coding and non coding regions of the genome. They CANT be used to make recombinant proteins or for gene therapy

Question 45

cDNA libraries (expression libraries)

Answer 45

contain smaller fragments of DNA and only include the exons expressed by the sample tissue. CAN be used to make recombinant proteins or for gene therapy

Question 46

Hybridization

Answer 46

is the joining of complementary bp sequences

Question 47

automated process by which millions of copies of a DNA sequence can be created from a very small sample by hybridization

Answer 47

Polymerase Chain Reaction (PCR)

Question 48

DNA molecules can be seperated by size using

Answer 48

agarose gel electrophoresis

Question 49

Southern Blotting

Answer 49

can be used to detect the presence and quantity of various DNA strands in a sample. After electrophoresis, the sample is transferred to a membrane that can be probed with single-stranded DNA molecules to look for a sequence of interest

Question 50

DNA sequencing uses____ which terminate the DNA chain bc they lack a 3'-OH. The resulting fragment can be seperated by _____ and the sequence can be read directly from the gel

Answer 50

dideoxyribonucleotides gel electrophoresis

Question 51

method of curing genetic deficiencies by introducing a functional gene with a viral vector

Answer 51

gene therapy

Question 52

created by integrating a gene of interest into the germ line of the embryonic stem cells of a developing mouse

Answer 52

transgenic mice and they can be mated to select for the transgene

Question 53

chimeras

Answer 53

are organisms that contain cells from two different lineages (such as mice formed from integration of transgenic embryonic stem cells into a normal mouse blastocyst)

Question 54

created by deleting a gene of interest

Answer 54

knockout mice