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AP Biology > The Molecular Basis of Inheritance > Flashcards

The Molecular Basis of Inheritance Flashcards

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1
Q

Griffith

A

● Performed experiements with several different strains of the bacterium Diplococcus pneumoniae in 1927
● Some strains are virulent and cause pneumonia in human and mice, and some strains are harmless
● He discovered bacterial transformation

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2
Q

Bacterial transformation

A

● bacteria have hte ability to transform harmless cells into virulent ones by transferring some genetic factor from one bacteria cell to another

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3
Q

Avery, Macleod, and McCarty

A

● Published their classic findings that Griffith’s transformation factor is DNA in 1944
● It proved that DNA was the agnet htat carried the genetic characteristics from the virulent dead bacteria tot he living nonvirulent bacteria
● Provided direct experimental evidence that DNA, not protein, was hte genetic material

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4
Q

Hershey and Chase

A

● Carried out experiments that lent strong support to the theory that DNA is the genetic material in 1952
● Proved that DNA from the viral nucleus, not protein from the viral coat, was infecting bacteria and producing thousands of progeny

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5
Q

Rosalind Franklin

A

● Carried out the X-ray crystallography analysis of DNA that showed DNA to be a helix in 1950-1953

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6
Q

Watson and Crick

A

● Proposed the couble helix structure of DNA in a one-page paper in the British journal Nature in 1953
● Two major pieces of informaiton they used were hte biochemical analysis of DNA and the X-ray diffraction analysis of DNA

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7
Q

Meselson and Stahl

A

● Proved that DNA replicates in a semiconservative fashion

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8
Q

Double helix

A

● Structure of DNA molecule

● Shaped like a twisted ladder, consisting of two strands unning in opposite directions–antiparallel

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9
Q

Nucleotides

A

● Consists of a 5-carbon sugar–doxyribose, a phosphate, and a nitrogen base

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10
Q

Nitrogenous bases

A

● Adenine (A) – purines
● Thymine (T) – pyrimidines
● Cytosine (C) – purines
● Guanine (G) – pyrimidines

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11
Q

Histones

A

● A large amount of proteins that combine with eukaryotic DNA
● Only separates briefly during replication

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12
Q

Chromatin

A

Comples of DNA plus histones

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13
Q

Nucleosomes

A

● THe double helix of DNA wraps twice around a core of histones forms nucleosomes
● Looks like beads on a string

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14
Q

Deoxyribonucleic aci

A

● DNA
● Double helix
● Made up of nucleotides

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15
Q

Ribonucleic acid

A

● RNA
● SIngle-strandd helix
● Four bases: Adenine, Cytosine, Guanine, and Uracil (U) that replaces thymine
● Has 5-carbon sugar called ribose

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16
Q

DNA replication

A

● The making of an exact replica of the DNA molecule by semiconservative replication
● THe DNA double helix unzips, and each strand serves as a template for the formation of a new strand composed of complementary nucleotides: A with T, C with G
● THe two new molecules each consist of one old strand and one new strand

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17
Q

Replication fork

A

● A Y-shaped region where the new strands of DNA are elongating
● At each end of the replication bubble

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18
Q

Replication bubbles

A

● Site of DNA replication

● Eventually all replication bubbles fuse

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19
Q

DNA polymerase

A

● Enzyme that catalyzes the antiparallel elongation of the new DNA strands
● Builds a new strand from the 5’ to the 3’ direction by moving along the template strand and pushing the replication fork ahead of it
● In humans, the rate of elongation is about 50 nucleotides persecond
● Cannot initiate synthesis

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20
Q

RNA primer

A

● produced by primase

● First binds to the template, allowing DNA polymerase to add nucleotides to to 3’ end of it

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21
Q

Primase

A

● Produce RNA primer

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22
Q

Leading strand

A

● Unbroken, linear fashing that is built in one of the strand
● Formed toward the replication fork

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23
Q

Lagging stand

A

● Formed away from the replication fork

● Form Okazaki fragments

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24
Q

Okazaki fragments

A

● Fragments in the lagging strand

● about 100-200 nucleotides long and will joined into one continuous strand by theenzyme DNA ligase

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25
Q

Helicases

A

● enzymes that untwist the double helix at the replication fork
● Separate the two parental strands, making these strands available as templates

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26
Q

Single-stranded binding proteins

A

● Act as scaffolding, holding the two DNA strands apart

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27
Q

Topoisomerases

A

● Lessen the tension on the ithgtly wound helix by breaking, swiveling, and rejoining the DNA strands

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28
Q

Mismatch repair

A

● proofreading that corrected errors

● Carries out by DNA polymerase

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29
Q

Telomeres

A

● Nonsesne nucleotide sequences at the ends of hte chromomes in eukaryotes
● Each time the DNA replicates, some nucleotides from the ends of the chromosomes are lost
● THye are created and maintained by the enzyme telomerase
● Normal body cells contain little telomerase–when it gets shorter overtime, this may serve as a clock that counts cell divisions and causes the cell to stop dividing as the cell ages

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30
Q

Transcription

A

● Process by which the information in a DNA sequence is copied (transcribed) into a complementary RNA sequence

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31
Q

Messenger RNA

A

● When a sequence of DNA is expressed, one of two starands of DNA is copied into mRNA according to the base-pairing rules

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32
Q

Ribosomal RNA

A

● Structural
● Along with proteins, it makes up the ribosome, which consists of two subunits, one large and one small
● THe ribosome has one mRNA binding site, and three tRNA binding sites, known as A, P, E sites
● Ribosome is a protein synthesis factory

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33
Q

Transcription RNA

A

● tRNA is shaped like a coverleaf and has a binding site for an amino acid at one end and another binding site foran anticodon sequence that binds to mRNA at the other

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34
Q

Initiation (trascription)

A

● RNA polymerase recognizes and binds to DNA at hte promoter region
● Once RNA polymerase is attached to the promoter, DNA transcription of the DNA template begins

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35
Q

Promoter

A

● Tells RNA polymerase where to begin transcription and which of the two strands to transcribe
● Transcription factors recognize the TATA box, and mediate hte binding of RNA polymerase to the DNA

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36
Q

TATA box

A

● a key area within the promoter, the TATA box, and mediate hte binding of RNA polymerase to the DNA

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37
Q

Transcription initiation complex

A

● THe completed assembly of transcription factors and RNA polymerase bound ot the promoter

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38
Q

Elongation (transcription)

A

● Contieus as RNA polymerase adds nucleotides to the 3’ end of a growing chain

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39
Q

RNA polymerase

A

● Binds to DNA at the promoter region
● Adds nucleotides to the 3’ end of a growing chain
● Pries the two strands of DNA apart and attaches RNA nucleotides according to the base pairing rules
● Has mechanisms for proofreading during transcription

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40
Q

Transcription unit

A

● The stretch of DNA that is transcribed into an mRNA molecule
● Each unit consists of codons

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41
Q

Codon

A

● Triplets of bases in mRNA

● Code for specific amino acids

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42
Q

Termination (Transcription)

A

● Final stage in transcription
● Elongation continues for a short distance after the RNA polymerase transcribes the termination sequence (AAUAAA)
● At this point, mRNA is cut free from the DNA template

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43
Q

RNA processing

A

● Before the newly formed pre-RNA strand is shipped out of the nucleus to the ribosome in the cytoplasm, it is altered or processed by a series of enzymes
● 5’ cap
● Poly A tail
● Splicing

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44
Q

5’ cap

A

● Consisting of a modified guanine nucleotide is added to the 5’ end
● This cap helps the RNA strand bind to the ribosome in the cytoplasm during translation

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45
Q

Poly A tail

A

● Consisting of a tring of adenine nucleotides
● Added to the 3’ end
● THis tail protects the RNA strand from degradation by hydrolytic enzymes, and facilitates the release of mRNA from the nucleus into the cytoplasm

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46
Q

Splicing

A

● Introns are removed by snRNPs, small nuclear ribonucleoproteins, and splicesomes
● This removal allows only exons to leave the nucleus
● mRNA that leaves the nucleus is a great deal shorter than the original transcription unit

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47
Q

Introns

A

● Noncoding regions of the mRNA

● AKA intervening sequences

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48
Q

Exons

A

● Expressed sequences

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49
Q

Alternative splicing

A

● Different RNA molecules are produced from the same primary transcript, depending on which RNA segments are treated as exons and which as introns
● Regulatory proteins specific to a cell type control intron-exon choices by binding to regulatory sequences within the primary transcript

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50
Q

Translation

A

● The process by which the codons of an mRNA sequence are changed into an amino acid sequence
● Include three steps: initiation, elongation, termination

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51
Q

Anticodon

A

● Nucleotid triplet on one end of the tRNA molecule specific to an amino acid
● Complementary to codons

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52
Q

Aminoacyl-tRNA synthetase

A

A specific enzyme that joins each amino acid to the correct tRNA

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53
Q

Start codon

A

● Codon AUG

- also codes for methionine

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54
Q

Stop codon

A

● UAA, UGA, UAG

● Terminate all sequences

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55
Q

Wobble effect

A

● The pairing rules for the third base of a codon are not as strict as they are for the fist two bases
● Ex) UCU, UCC, UCA, UCG all code for the amino acid serine

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56
Q

Initiation (Translation)

A

● Begins when mRNA becomes attached to a subunit of the ribosome
● First codon is always AUG
- It must be positioned correctly in order for transcription of an amino acid sequence to begin

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57
Q

Elongation (Translation)

A

● Continues as tRNA brings amino acids to the ribosome and polypeptide chain is formed
● One mRNA molecule is generally translated simultaneously polyribosomes

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58
Q

Polyribosomes

A

Several ribosomes in clusters

59
Q

Termination (Translation)

A

● Complete when a ribosome reaches one of three termination or stop codons
● The polypeptide chain of amino acid is freed by the release factor from the ribosome and mRNA is broken down

60
Q

Release factor

A

● Breaks the bond between the tRNA and the last amino acid of hte polypeptide chain

61
Q

Mutations

A

● Permanent changes in genetic material
● Occur spontaneously and randomly
● Can be caused by mutagenic agents, including toxic chemicals and radiation
● In somatic cells disrupts normal cell functions
● Are the raw material for natural selection
● In gametes are transmitted to offspring and can change the gene pool of a population

62
Q

Point mutation

A

● Base-pair substitution
● Responsible for sicke cell anemia–abnormal hemoglobin that can cause red blood cells to sickle when oxygen tension is low
- A variety of tissues may be deprived of oxygen and suffer severe, permanent damage
● Could result in a beneficial change or no change (wobble)

63
Q

Base-pair substitution

A

A chemical change in just one base pair in a single gene

64
Q

Insertion/deletion

A

Addition or loss of one letter into the DNA sentence

65
Q

Frameshift

A

● Insertion and deletion are a type of this kind

● The entire reading frame is altered

66
Q

Missense mutation

A

When point mutations or frameshifts change a codon within a gene into a stop codon, translation will be altered into a missense mutation (different meaning)

67
Q

Nonsense mutation

A

When point mutations or frameshifts change a codon within a gene into a stop codon, translation will be altered into a nonsense mutation (produce a stop codon)

68
Q

Virus

A

● Parasite htat can live only inside another cell

● Commandeers the host cell machinery to transcribe and translate all the proteins it needs to fashion new viruses

69
Q

Capsid

A

A protein coat enclosing DNA or RNA in a virus

70
Q

Virual envelope

A

● Derived from membranes of host cells
● Cloaks the capside
● Aids the virus in infecting the host

71
Q

Host range

A

The range of organisms that a virus can attack

72
Q

Bacteriophages

A

● The most complex and best understood virus
● Infects bacteria
● Can reproduce in different ways

73
Q

Lytic cycle

A

● The phage enters a host cell, takes control of the cell achinery, replicates itself, and then causes hte cell to burst, releasing a new generation of infectious phage viruses
● These new viruses infect and kill thousands of cell sin the same manner

74
Q

Lysogenic cycle

A

● Viruses replicate without destroying the host cell
● The phage virus become sincorporated into a specific site in the host’s DNA
● It remains dormant within the host genome and is called a prophage
● As the host cell divides, the phage is replicated along with it and a single infeced cell gives rise to a population of infected cells
● At some point an environmental trigger causes the prophasge to switch to the lytic phase

75
Q

Temperate viruses

A

Viruses capable of both modes of reproducing, ltic and lysogenic, within a baceterium

76
Q

Virulent phage

A

A phage that replicates only by a lytic cycle

77
Q

Retroviruses

A

● Viruses that contain RNA instead of DNA and replicate in an unusual way
● Following infection of the host cell, the retrovirus RNA serves as a template for the synthesis of complementary DNA
● They reverse the usual flow of information from DNA to RNA
● Usually inserts itself into the host genome, becomes a permanent resident, called a prophage, and is capable of making multiple copies of hte viral genome for years

78
Q

Reverse transcriptase

A

An enzyme that direct the reverse transcription process taken by retroviruses

79
Q

Transduction

A

● Phage viruses acquire bits of bacterial DNA as they infect one cell after naother
- This process, which leads to genetic combination, is called transduction

80
Q

Generalized transuction

A

● Moves random pieces of bacterial DNA as the phage lyses one cell and infects another during the lytic cycle

81
Q

Restricted/Specialized transduction

A

● Involves the transfer of specific pieces of DNA
● During the lysogenic cycle, a phage integrates into the host cell at a specific site
● At a later time, when the phage ruptures out of the host DNA, it sometimes carries a piece of adjacent host DNA with it and inserts this host DNA into the next host it infects

82
Q

Bacterial chromosome

A

● Ciruclar, double-stranded DNA molecule
● Tightly condensed into a structure called a nucleoid–no nuclear membrane
● Replicate in both directions from a single point of origin

83
Q

Conjugation

A

● Primitive sexual reproduction by bacteria

● Bacterias exchange DNA

84
Q

Binary fission

A

● The main mode of reproduction of bacteria
● Asexual
● Results in a population with all identical genes, but mutations do occur spontaneously

85
Q

Bacterial transformation

A

● Either a natural or an artificial process tha tprovides a mechanism for the recombination fo genetic information in some bacteria
● Small pieces of extracellular DNA are taken up by a living bacterium, ultimately leading to a stable genetic change in the recipient cell

86
Q

Plasmid

A

● Foreign, small, circular, self-replicating DNA molecule that inhabits a bacterium
● A bacterium can harbor many plasmids and will express the genes carried by the plasmid

87
Q

F plasmid

A

● First plasmid discovered
● F stands for fertility
● Bacteria that contain the F plasmid are called F+; others are called F-
● Contains genes fro the production of pili

88
Q

Pili

A

● Cytoplasmic bridges that connect to an adjacent cell

● Allows DNA to move from one cell to another in a form of primitive sexual reproduction called conjugation

89
Q

R plasmid

A

● Makes the cell in which it is carried resistant to specific antibiotics, such as ampicillin or tetracycline
● Can be transferred to other bacteria by conjugation
● Bacteria that carry this have a distinct evolutionary advantage

90
Q

Operon

A

● Disvoered in the bacterium E. coli
● Important model of gene regulation
● A set of genes and the switches that control the expression of those genes

91
Q

Inducible/lac operon

A

● Three enzymes, B-galactosidase, permease, and transacetylase, must be synthesized to break down lactose into glucose and galactose
● In order for these three genes to be transcribed, the repressor must be prevented from binding tot he operator and RNA polymerase must bind to the promoter region
● Allolactose is the inducer that facilitates this process by binding to the active repressor and inactivating it

92
Q

Repressible/tryptophan operon

A

● Consists of a promoter and five adjacent structural genes (A,B,C,D,E) that code for five separate enzymes necessary to synthesize the amino acid trypotophan
● As long as RNA polymerase binds to the promoter, one long strand of mRNA containing start and stop codons is transcribed
● If adequate tryptophan is present, tryptophan itself acts as a corepressor activating the repressor
● The activated repressor binds to the operator, preventing RNA polymerase from binding to the promoter
● Transcription ceases

93
Q

CAP and cAMP

A

● Catabolite activator protein and cyclic AMP
● Allosteric regulatory protein that switches the energy source to lactose when glucose is in short supply
● The attachment of CAP to the promoter directly stimualtes gene expression

94
Q

Positive gene regulation

A

● Directly stimulates gene expression

● Ex) Attachment of CAP

95
Q

RNA polymerase

A

Enzyme that transcribes a new RNA chain by linking ribonucleotides to nucleotids on a DNA template

96
Q

Operator

A

● Sequence of nucleotides near the start of an operon to which the active repressor can attach
● The binding of the repressor prevents RNA polymerase from attaching tot he promoter and transcribing the operon’s genes

97
Q

Promoter

A

● Nucleotide sequence in the DNA of a gene that is hte binding site of RNA polymerase, positioning the RNA polymerase to begin to transcribe RNA at hte appropriate position

98
Q

Repressor

A

● Protein that inhibits gene transciption

● In the operon of prokaryotes, repressors bind tot he operator

99
Q

Regulator gene

A

● Gene that codes for a repressor

● It is located some distance from its operon and has its own promoter

100
Q

Prions

A

● Misfoolded versions of a protein normally foudn in the brain
● They cause all the normal versions of hte protein to misfold in the same way
● Infectious and cause several brain diseases
- Scrapie in sheep
- Mad cow disease in cattle
- Creutzfeldt-Jakob disease in human

101
Q

Tandem repeats

A

Back-to-back repetitive sequences

102
Q

Telomeres

A

● made up of tandem repeats

● At the end of DNA strands to protect the DNA from information loss

103
Q

Polymorphic regions

A

● Certain noncoding regions of DNA

● Are highly variable from one region to the next

104
Q

Histones

A

● Eukarotic DNA is packaged with proteins called histones in an elaborate complex knwon as chromatin, the basic unit of which is the nucleosome
● Changes to the histone structure alter chromatin configuration, binding it more tightly or more loosely, thus making DNA less or more accessible for transcription and expression

105
Q

Acetylation of histone tails

A

● Adding of acetyle groups (-COCH3) to the histone tails
● Promotes the loosening of that chromatin structure and permits transcription
● Removal of acetyl groups block transcription

106
Q

Methylation of certain bases

A

● Adding methyl groups–CH3 to DNA
● Silences the DNA temporarily or for long periods of time
● Removal of methyl groups can turn genes on
● Probably responsible for the long-term X-chromosome deactivation in females and genes necessary fro normal cell differentiation in embryonic development

107
Q

Epigenetic inheritance

A

● Alterations to the genome that do not directly invovle the nucleotide sequence
● THese chagnes are reversible
● Environmental factors like diet, stress, and prenatal nutrition can alter the expression of genes

108
Q

Degradation of mRNA

A

● Bacterial mRNA molecules are degraded within minutes of their synthesis
● THis rapid degradation of mRNA may be the reason that bacteria change their patterns of protein synthesis and are so adpatable to changes in the environemnt
● human mRNA may continually translate protein for hours or weeks
● molecules of mRNA in developing red blood cells are stable and may translate hemoglobin molecules repeatedly for an exteended time

109
Q

Noncoding RNA

A

● ncRNA
● Bind to and are assisted by specialized binding proteins called Argonaute proteins
● They regulate much of our DNA

110
Q

MicroRNA

A

● miRNA
● Single-stranded RNA about 22 nucleotides long, forms a complex with proteins
● Targets specific mRNA molecules to either dgrade them or block their translation

111
Q

Small interfering RNA

A

● siRNA
● Similar to miRNA in size and function
● The blocking of gene expression by siRNA is called RNA interference (RNAi)

112
Q

Piwi-associated RNA

A

● piRNA
● Recently discovered
● Large class of ncRNAs that guide PIWI proteins to complementary RNAs which are derived from transposable elements
● Similar to RNAi, they protect germ line cells from attack by transposons

113
Q

Recombinant DNA

A

● Tkaing DNA from two or more sources and combining them into one molecule
● occurs in nvature during viral transcution, bacterial transformation, and conjugation and when transposons jump around the genome
● Scientists can also manipulate the gnes–biotechnology or genetic engineering

114
Q

Vector

A

A cell that will carry the plasmid, such as a bacterium

115
Q

Restriction enzymes

A

● Extracted from bacteria
● Cut DNA at specific recognition sequences or sites, such as GAATTC
- OFten these cuts are staggered, leaving single-stranded sticky ends to form a temporary union with other sticky ends

116
Q

Restriction fragments

A

The fragments that result from the cuts made by restriction enzymes

117
Q

Gel electrophoresis

A

● Separates large molecules of DNA on the basis of their rate of movement through an agarose gel in an electric field
● The smaller the molecule, the faster it runs
● The concnetration of the gel can be altered to provide a greater impediment to the DNA, allowing for finer separation

118
Q

DNA probe

A

● Identify the location of a specific sequence within the DNA
● Radioactively labeled single strand of nucleic acid molecule
● Bonds to the complementary sequence wherever it occurs, and hte radioactivity enables scientists to detect its location

119
Q

Polymerase Chain Reaction (PCR)

A

● Cell-free, automated technique by which a piece of DNA can be rapidly copied or amplified
● The DNA piece htat is to be amplified is placed into a test tube with Taq polymerase along with a supply of nucleotides and primers necessary for DNA synthesis

120
Q

Restriction fragment length polymorphism (RFLPs)

A

● The differences of the restriction fragment pattern in every individual
● A RFLP analysis of someone’s DNA gives a human DNA fingerprint that looks like a bar code
● Used in paternity suits to determine if a particular man is hte father of a particular child
● Routinely used to identify the perpetrator in rape and murder cases

121
Q

Complementary DNA (cDNA)

A

● DNA produced by retroviruses–without introns
● Extract fully processed mRNA from cells and then use the enzye reverse transcriptase to make DNA transcripts of this RNA
● The resulting DNA molecule carries the complete coding sequence of interest but without introns

122
Q

Clustered Regularly Interspersed Short Palindromic Repeats (CRISPR)

A

● Genetic engineering tool made of RNA that can be guided to modify a stretch of DNA
● THe targets a particular sequence and permanently disrupts it or can add small pieces of corrective DNA to the same location

123
Q

DNA chips

A

● DNA probes are being coupled with the technology of the semiconductor industry to produce DNA chips that are about 1/2 inch square and can hold personal information about someone’s genetic makeup
● The chips scan a person for mutations, including mutations in the immune system or the breast cancer genes and for a predisposition to tother cancers or heart attacks

124
Q

What’s the paring pattern in nitrogenous bases?

A

● Adenine nucleotide bonds by a double hydrogen bond to the thymine nucleotide
● Cytosine nucleotide bonds by a triple hydrogen bond to the guanine nucleotide

125
Q

Where and how does DNA replication begin?

A

● Speical sites called origins of replication, where hte two strands of DNA separate to form replication bubbles
● Thousands of these bubbles can be seen along the DNA molecule by using the giant DNA molecule that consists of 6 billion nucleotids
● A replication bubble expands as replication proceeds in both directions at once

126
Q

What are the enzymes used in DNA replication (in order)?

A
  1. Helicase
  2. Single-stranded binding protein
  3. Topoisomerase
  4. Primase
  5. DNA polymerase I
  6. Nuclease
  7. DNA polymerae III
    8 Ligase
127
Q

Give a sumaary of how DNA makes protein.

A

● THe triplet code in DNA is transcribed into a codon seuence in messenger-RNA inside the nucleus
● This newly formed strand of RNA, knwon as pre-RNA, is processed or modified in the nucleus
● THe codon sequence leaves the nucleus and is translated into an amino acid sequence (a polypeptide) in the cytoplasm at the ribosome

128
Q

What are the kinds of RNA invovled in protein synthesis?

A

● Messenger RNA is invovled in transcription
● Ribosomal RNA is invovled in translation
● Transcription RNA carries amino acids from the cytoplasmic pool of amino acids to mRNA at the ribosome

129
Q

What does the tRNA do in translation?

A

● Brings amino acids present in the cytoplasm to the codons of hte mRNA strand at hte ribosome according to the base pairing rules
● Can be used repeatedly

130
Q

What energy provide for translation?

A

● Guanosine triphosphate (GTP)

● A molecule closely related to ATP

131
Q

Why do some tRNA molecules have anticodons that can recognize two or more different codons?

A

Wobble effect

132
Q

What does “there are redundancies in the code, but htere is no ambiguity” mean?

A

● Many codons can cod for the same amino acid–redundancy

● One codon only codes for one particular amino acid–no ambiguity

133
Q

Why are some regions of DNA more vulnerable to mutations than others?

A

● Regions of As and Ts are subject to more breakages than regions of Cs and Gs
● A and T are connected by a double hydrogen bond whereas Cs and Gs are connected by a triple hydrogen bond

134
Q

Why can each type of virus only infect one specific cell type?

A

Because it gains entrance into a cell by binding to specific receptors on the cell surface

135
Q

What are the two wyas a bacteriophage can reproduce itself?

A

● Lytic cycle

● Lysogenic cycle

136
Q

Why do bacteria with R plasmid have an evolutionary adtage over bacteria that are not resistant to antibiotics?

A

Resistant bacteria will be selected for (survive) and their populations will increase while nonresistant bacteria die out

137
Q

When glucose and lactose are both present in the intestine, what does E. coli preferentially metabolize?

A

Glucose

138
Q

What are the potential uses of recombinant DNA or gene cloning?

A

● To produce a protein product, such as human insulin, in large quantities as an inexpensive pharmaceutical
● To replace a nonfunctioning gene in a person’s cells with a functioning gene by gene therapy
- Sometimes the human subjects become ill from the viral vector used to carry the gene
- Other times, the gene is inserted successfully and begins to produce hte necessary protein but stops working in a short time
● To prepare multiple copies of a gene itself for analysis
● To engineer bacteira to clean up the environment
- One modified species can even eat toxic waste

139
Q

What are the steps of gene cloning

A

● Isolate a gene of interest
● Insert hte gene into a plasmid
● Insert the plasmid into a vector
- A bacterium must be made competant, which means be able to take up a plasmid
● Clone the gene
- As the bacteria reproduce themsleves by fission, the plasmid and the selected gene are also being cloned
● Identify the bacteria that contain the selected gene and harvest in from the culture

140
Q

How can the gel electrophoresis be used?

A

● To separate protein and amino acids
● DNA must be cut up by restriction enzymes into pieces amll enough to migrate through a gel
● The DNA can be analyzed in many ways once separated
- The DNA strands can be sequenced to determine the sequence of bases A,C,T,G
- The gel can also be used in a comparison with other DNA samples

141
Q

What are the limitations of the PCR technique?

A

● Some information about the nucleotide sequence of the target DNA must be known in advance in order to make the necessary primers
● The size of the piece htat can be amplified must be very short
● Contamination is a major problem
- A few skin cells from the technician working with the sample could make obtainin accurate results difficult or impossible

142
Q

Why can’t scientist clone a human gene in a bacterium without treating it?

A

● The human genes have introns but the bacterias don’t

● The bacterium have no way to edit the introns out after transcription

143
Q

What are some safety concerns of genetic enginnering?

A

● Individuals are concerned that the genes that have been inserted into the vegetables may be dangerous to those who eat them

144
Q

What are some privacy concerns of genetic engineering?

A

● The possibiity that the personal iinformation on a DNA chip might not remain private has caused much controversy
● Health insurance company might charge you a higher premium

AP Biology (15 decks)

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