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Biochem Ch. 6--DNA and Biotechnology

Terms in this set (82)

Macromolecule that stores genetic info in all living organisms
DNA
Contain 5-carbon sugar bound to a nitrogenous base
Nucleosides
Nucleosides with one to three phosphate groups attached
Nucleotides
Nucleotides in DNA contain?
deoxyribose
Nucleotides in RNA contain?
Ribose
DNA is organized according to the?
Watson-Crick model
DNA is always read 5' to?
3'
DNA contains two strands with ? polarity
antiparallel
Adenine and Guanine are known as?
Purines
Cytosine, Uracil and Thymine are known as?
Pyrimidines
Nucleotides are bonded together by two?
Hydrogen bonds
Purines and pyrimidines are?
aromatic heterocyles
Aromatic compounds are cyclic, planar and?
conjugated
The different multiples of pi bonds that can be in an aromatic compound is governed by Huckle's rule and include 6, 10 and?
14
The notion that purines and pyrimidines are equal in number in a DNA molecule is known as?
Chargaff's rules
Most DNA is B-DNA, forming a?
right-handed helix
Z-DNA is present in low concentrations and takes which shape?
zig-zag
High GC content or high salt concentration is common in which type of DNA?
z-Dna
When DNA is brought back together after being denatured, it is said to be?
reannealed
In order to denature DNA pH needs to be acidic or alkaline?
alkaline
DNA is organized into how many chromosomes in human cells?
46
In eukaryotes, DNA is wound around?
histone proteins
H2A, H2B, H3, and H4 are all major classes of _______________.
histones
A bunch of histone proteins with DNA wound around them form ?
nucleosomes
The histone protein H1 can be used to stabilize?
nucleosomes
As a whole, DNA and its associated histones make up?
chromatin
Heterochromatin is dense, transcriptionally silent DNA that appears ? under light microscopy
dark
less dense, transcriptionally active DNA that appears light under light microscopy
euchromatin
Telomeres are located at?
ends of chromosomes
What contains high GC content to prevent unraveling of DNA?
telomeres
During which part of the cell cycle do telomeres slightly shortened?
During replication
The shortening of telomeres can be partially reversed by which enzyme?
telomerase
Centromeres and Telomeres have what in common?
high GC content (aids in strong bonds)
A set of specialized proteins that assist the DNA polymerases
replisome (replication complex)
To replicate DNA, it is first unwound at ________ by ________
origin of replication, helicases
after helicase unzips DNA during replication, two ? are produced on either side of the origin
replication forks
? have a circular chromosome that contains only one origin of replication?
Prokaryotes
? have linear chromosomes that contain many origins of replication?
Eukaryotes
Unwound DNA strands are kept from reannealing or being degraded by?
single-stranded DNA binding proteins
Supercoiling causes torsional strain on the DNA molecule, which can be eased by?
DNA topoisonmerase II (DNA gyrase)
The fact that during DNA replication, one old parent strand and one new daughter strand is incorporated into each of the two new DNA molecules is what makes this process?
Semi-conservative
DNA cannot be synthesized without an adjacent nucleotide to hook onto, so a
small RNA primer is put down by _______
primase
DNA can be synthesized in eukaryotes by DNA polymerase alpha or?
delta
In prokaryotes what is used to synthesized DNA?
DNA polymerase III
When synthesizing DNA, ? reads the template DNA 3' to 5' and synthesize the new strand 5' to 3'
DNA polymerase
The ? only requires one primer and can then be synthesized continuously in its entirety?
Leading strand
The lagging strand requires many primers and it synthesized in discrete sections called?
Okazaki fragments
In prokaryotes, before synthesis has occured, RNA primers can later be removed by which DNA polymerase?
DNA polymerase I
In eukaryotes, after synthesis has occured, RNA primers can be removed by?
RNase H
Oncogenes develop from mutation of ? and promote cell cycling.
proto-oncogenes
What is defined by the unchecked cell proliferation with the ability to spread by local invasion?
Cancer
Metastisis occurs when cancerous cells migrate via bloodstream or ?
lymphatic system
? code for proteins that reduce cell cycling or promote DNA repair
tumor supressor genes
A mutation of a tumor suppressor gene can lead to?
cancer
The daughter strand is identified by its lack of ? and corrected accordingly
methylation
The genes MSH2 and MLH1 are used for ? during the G2 phase of the cell cycle?
mismatch repair
Excision endonuclease is used during nucleotide excision repair to fix?
helix-deforming lesions of DNA (such as thymine dimers)
Base excision repair fixes?
nondeforming lesions of the DNA helix ex.) cytosine deamination
Base excision repair fixes nondeforming lesions of the DNA helix by removing the base, leaving ?
apurinic/apyrimidinic (AP) site
After base excision repair has occured, AP endonuclease removes?
damaged sequence
DNA composed of nucleotides from two different sources
Recombinant DNA
DNA cloning introduces a fragment of DNA into a?
Vector plasmid
Another word for restriction enzyme is restriction ___?
endonuclease
During DNA cloning, a restriction enzyme/endonuclease cuts both plasmid and fragment which are left with?
sticky ends
During DNA cloning, after the fragment binds to the plasmid, it can be injected into a ___ so that replication can occur, generating many copies of the fragment of interest?
bacterial cell
Vectors contain an origin of replication, the fragment of interest, and ?
gene for antibiotic resistance
Large collections of known DNA sequences are known as?
DNA libraries
Genomic libraries contain large fragments of ?
DNA
The DNA from genomic libraries cannot be used to make recombinant proteins or for ?
gene therapy
contain smaller fragments of DNA, and only include the exons of genes expressed by the sample tissue; can be used to make recombinant proteins or for gene therapy
cDNA libraries
cDNA libraries are also known as ?
expression libraries
One major difference between cDNA libraries and regular DNA libraries is that cDNA can be used to make ?
recombinant proteins or (for gene therapy as well)
The joining of complementary base pair sequences
Hybridization
Automated process by which millions of copies of a DNA sequence can be created from a very small sample by hybridization?
polymerase chain rxn (PCR)
Agarose gel electrophoresis separates DNA molecules by?
size
Southern blotting can be used to detect?
presence and quantity of various DNA strands in a sample
After electrophoresis, a DNA sample can be transferred to a membrane that can be probed with ? to help look for a sequence of interest?
single-stranded DNA
DNA sequencing uses dideoxyribonucleotides , which terminate the DNA chain because the lack a ?
3'-OH group
A method of curing genetic deficiencies by introducing a functional gene with a viral vector
gene therapy
Created by integrating a gene of interest into a germ line or embryonic stem cell of developing mouse.
Transgenic mice
Organisms that contain cells form two different lineages are called?
chimeras
Knockout mice are created by ? a gene of interest
deleting
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