Chapter 20 Flashcards Preview

AP Biology Semester 1 > Chapter 20 > Flashcards

Flashcards in Chapter 20 Deck (45):
1

recombinant DNA

nucleotide sequences from 2 different sources, often two species, are combined in vitro into the same DNA molecule

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genetic engineering

the direct manipulation of genes for pratical purposes

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biotechnology

the manipulation of organisms or their genetic components to make useful products

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DNA cloning

well defined segments of DNA in identical copies

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plasmids

small circular DNA molecules that replicate separately from the bacterial chromosome

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why are cloned genes useful?

to make copies of a particular gene and producing a protein product

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gene cloning

involves using bacteria to make multiple copies of a gene
-foreign DNA is inserted into plasmid, and then that plasmid is inserted into a bacterial cell
-reproduction in the bacterial cell results in cloning of the plasmid including the foreign DNA
-this results in the production of multiple copies of a single gene

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restriction enzymes

cut DNA molecules at specific DNA sequences called restriction sites

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restriction fragments

when a restriction enzyme makes many cuts this creates restriction fragments

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sticky ends

most useful restriction enzymes cut DNA in a staggered way making sticky ends

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DNA ligase

an enzyme that seals the bonds between restriction fragments

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cloning vector

the original plasmid
-can carry foreign DNA in a host cell and replicate there

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genomic library

the collection of recombinant vector clones produced by cloning DNA fragments from an entire genome

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bacterial artificial chromosome (BAC)

large plasmid that has been trimmed down and can carry a large DNA insert

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complementary DNA (cDNA)

made by cloning DNA made in vitro by reverse transcription of all the nRNA produced by a particular cell

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nucleic acid probe

a way to identify a gene of interest... has a sequence complementary to the gene being seeked..this process is called nucleic acid hybridization

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cloned genes can be expressed as protein in (bacteria or eukaryotic cells?)

BOTH

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expression vector

a cloning vector that contains a highly active bacterial promoter

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electroporation

applying brief electrical pulse to create temporary holes in the plasma membranes
-a method of introducing recombinant DNA into eukaryotic cells

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polymerase chain reaction (PCR)

can produce many copies of a specific target segment of DNA
-a 3 step cycle (heating, cooling, and replication) brings about a chain reaction that produces an exponentially growing population of identical DNA molecules

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Taq polymerase

a PCR that is very useful because it can work in very extreme temperatures and still produce copies of a specific target segment

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what does cloning allow researchers to do (3)

1. compare genes and alleles between individuals
2. locate gene expression in a body
3. determine the role of a gene in an organism

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gel electrophoresis

-analyzing and comparing genomes
-separates nucleic acids by size, electrical charge (goes from negative to positive)

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polymorphisms

variations in DNA sequence

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RFLPs (restriction fragment length polymorphisms)

sequence changes that alter restriction sites
-a variation in the length of restriction fragments produced by a given restriction enzyme in a sample of DNA.

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southern blotting

combines gel electrophoresis and DNA fragments with nucleic acid hybridization

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what is used to compare mRNA from different developmental stages

1. northern blotting
2. reverse transcriptase- polymerase chain reaction

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northern blotting

an adaptation of the Southern blot procedure used to detect specific sequences of RNA by hybridization with complementary DNA.

29

reverse transcriptase polymerase chain (RT-PCR)

quicker and more sensitive because it requires less mRNA than Northern blotting
-added to mRNA to make cDNA, which serves as a template for PCR amplification of the gene of interest
-products are run on a gel and the mRNA of interest idnetified

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situ hybridization

uses flourescent dyes attached to probes to identify the location of a specific mRNAs in place in the intact organism

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DNA microarray assays

compare patterns of gene expression in different tissues, at different times, or under different conditions

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in vitro mutagenesis

use this, mutations are introduced into a clone gene, altering or destroying its function

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what are ways to determine gene function

1. disable gene and observe consequences
2. mutations with vitro mutagenesis then when mutated gene is returned to cell, the normal genes function might be determined by examining the mutants phenotype

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RNA interference

Synthetic double-stranded RNA molecules matching the sequence of a particular gene are
used to break down or block the gene’s mRNA

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SNPs (single nucleotide polymorphisms)

genetic markers

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totipotent cell

on that can generate a complete new organism

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stem cell

unspecialized cell that can reproduce itself indefinitely and differentiate into specialized cells of one or more types

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embryotic stem cells can make:

1. liver cells
2. nerve cells
3. blood cells

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adult stem cells

1. blood cells

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gene therapy

alteration of an afflicted individuals genes (very risky)
-vectors are used for delivery of genes into specific types of cells

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transgenic

made by introducing genes from one species into the genome of another animal
-these animals are pharmaceutical "factories" producers of large amounts of substances for medical uses

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genetic profile

individuals DNA sequence

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short tandem repeats

variations in the number of repeats of a specific DNA sequence

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Ti plasmid

most commonly used vector for introducing new genes into plant cells

45

GMO

-putting pesticides on plants so animals dont eat them and thus can have a bigger output in product