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255 Cards in this Set

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DNA Polymerase
starts DNA synthesis; enzyme that takes the substrate; during replication, an enzyme that joins the nucleotides complementary to a DNA template
DNA Helicase
enzyme that helps unwind the 2 DNA strands in DNA replication; type of DNA polymerase?
DNA ligase
enzyme that joins strands together to make DNA backbone; type of DNA polymerase substrate?; used during prod of recombinant DNA to join foreign DNA to vector DNA
not confined to nucleus - occurs in both nucleus and cytoplasm; like DNA, is a polymer of nucleotides; contains uracil for base; mRNA, tRNA, and rRNA
messenger RNA
mRNA; takes a message from DNA in the nucleus to the ribosomoes in the cytoplasm; codes for proteins (codons); 3 bases; unstable (must adapt quickly); heterozygous
Transfer RNA
tRNA; transfers amino acids to the ribosomes; covalent bond to AA's; small; contains anti-codons
Ribosomal RNA
rRNA; along with proteins, makes up the ribosomes, where polypeptides (amino acids) are synthesized; structural component; stable; different sizes
DNA->RNA; DNA serves as a template for RNA formation, then RNA moves into cytoplasm; forms mRNA; binds to RNA polymerase or promoter/enhancer sequence; DNA unwinds and exposes base pairs (helicase); is dependent on mRNA synthesis
RNA->mRNA->Proteins; mRNA transcript directs the sequence of amino acids in a polypeptide; ribosomoes; genetic code; mRNA is involved in polypeptide synthesis; ribosome scans down mRNA looking for start codon and then finds each's anti-codon; stops when reaches stop codon
RNA->DNA; Exception to transcription and translation?; Ex = HIV; ssRNA->RNA->DNA->dsDNA; reverse transcriptase
1 codon = 3 bases (triplets); base sequence in mRNA that causes the insertion of a particular AA into a protein, or termination of translation
triplet code
main feature of code; each codon in genetic code consists of 3 nucleotide bases
3 Properties of the genetic code
1. the genetic code is degenerate - most AA have more than 1 code
2. gen code is unambiguous - each triplet codon has only 1 meaning
3. gen code has 1 start and 3 stop signals
Genetic Code
64 codons total (but only 61 code for AA's); specifies protein synthesis in the cells of all living things; the genetic code is a triplet code; each codon consists of 3 DNA nulceotides (U,A,G,C); except for the 3 stop codons, all the codons code for the 20 AA's; redundant
RNA polymerase
enzyme that is involved in transcription
defines the start of a gene, the direction of the transcription, and the strand to be transcribed; binding site for RNA Polymerase
causes RNA polymerase to stop transcribing the DNA and to release the mRNA molecule (which is now RNA transcript)
RNA transcript
mRNA molecule formed during tansciption that has a sequence of bases complementary to a gene
only in Eukaryotes; segments of DNA that are never expressed; junk sequences; don't code for anything
segments of DNA that are expressed
complex enzyme with RNA on the nuclear membrane that contains several kinds of ribonucleoproteins; cuts the primary mRNA (removes introns) and then rejoins the adjacent exons
RNA's with an enzymatic function; each one leaves RNA only at specific locations
the opposite end of a molec, group of 3 bases that is complementary to a specific codon of mRNA (the opposite; Ex: GAA - CUU); tRNA's
complex of several ribosomes are often attached to and translating the same mRNA
What are the anti-codon's for each base pair (U,A,G,C)?
U - A
G - C
What are the 4 types of microbial genetics?
Bacteria, Viruses, Yeast, Neurospora
What are the 3 types of mutants?
Antibiotic resistant (Ex: Penicillin), Auxotrophs (requires something else for growth), Conditional Lethal (Temperature Sensitive)
requires something for its own growth; opposite of prototroph; Ex: E.Coli Arginine
Conditional Lethal
Type of mutant; under certain conditions (temp) it is lethal; Ex: Polyoma virus
Two ways to isolate mutants?
Agar petridish (only ones that grow are resistant); Prototype (Replica plating)
Replica plating
Mutagenize cells in order to find an auxotroph; plate cells on medium containing arginine, touch plate to velvet, transfer to new, clean plate; everything grows except for auxotrophs; use with different temps, like auxotrophs
gene regulation in only prokaryotes; cluster of genes that are coordinate patrolled: either turned on or off; contains promoter, operator, and structural genes
can exist and replicate on their own (independent of cell DNA) in states of either plasmid or genome; Ex is F-Factor
self-duplicating circular ring of accessory DNA in the cytoplasm of bacteria; common vector of rDNA
Way to achieve genetic diversity in bacteria; Genetic DNA elements that jump around, moving stuff, found in bacteria and humans; specific DNA sequence capable of randomly moving from one site to another in the genome and between chromosomes
Genetic engineering
Alteration of genomes for medical or industrial purposes
E.Coli males
have F+ Factor (which codes for proteins and allows male DNA -> female cell); exists as plasmids
E.Coli females
don't have the F- Factor; exists as a plasmid
E.Coli Supermales
Hi Frequency Recombination; have F- Factor integrated into genome; episome
What are the 4 ways to achieve Genetic Diversity?
Mutation, Mating/Recombination, Viral "transduction", Transposons
Exchange of DNA between bacteria by means of a bacteriophage
enzyme that monitors activity of transposons; it is induced when glucose is gone and lactose is present; breaks down the disaccharide lactose -> glu -> galactose
Regulator genes
Promotor gene and operator gene; they don't code for proteins, codes for a repressor that controls whether the operon is active or not
Lactose operon
When a segment in a genome is denied glucose and has lactose present it immediately begins to make 3 enzymes needed for the the metabolism of lactose (1 of which is B-galactosidase); uses regulator genes; in prokaryote is a binding site for RNA polymerase, in eukaryote is a binding site for a repressor protein
An inducer for lactose operons that combines with repressor protein to make repressor fall off of proteins
Lactose Promoter
is weak: low affinity for RNA polymerase -> small amounts of B-gal made
Cyclic Adenosine Mono Phosphate; used to activate protein kinase and protease (thus releasing glycose); 2nd messenger in Fight or Flight
CAP; CRP (What do they stand for?)
Captain Crap: CAP = Catabolic Activator Protein; CRP = cAMP Receptor Protein
cAMP-CRP Complex
Activates lactose promoter, protein regulation, RNA Polymerase binds efficiently; High Glucose = Low cAMP level, Low Glucose = High cAMP level
Promoter Gene
A short sequence of DNA where RNA polymerase first attaches when a gene is to be transcribed
Operator Gene
A short portion of DNA where an active protein repressor binds. When an active repressor is bound to the operator, RNA polymerase cannot attach to the promoter and transcription does not occur
a portion of DNA wrapped around a group of histone molecules
Genetic mutation
a permanent change in the sequence of bases in DNA
mutagens that increase the chances of cancer
Genetic Mutations
due to a change in base sequences, or errors in replication, environmental mutagens, or transposons
Restriction Enzymes (RE)
see's palindromic sequences and cuts DNA into fragments; enzyme needed to introduce foreign DNA into vector DNA; cleaves DNA; ends up with sticky ends
Same forwards as backwards; Ex:
Recombinant DNA molecule
2 sticky DNA fragments that stick together by base pairing, DNA ligase
Cloning Vector
agent used to introduce new DNA into a host cell; 3 types: Plasmid, Phage, Mammalian Viruses
Small circular DNA molecules found in many bacteria; type of cloning vector
Viruses that specifically infect bacteria; some leave many surviving cells with viral DNA in lost cell's DNA; type of cloning vector
Mammalian Viruses
Use infected viruses that don't kill infected lost cells; type of cloning vector
Gene Cloning
Cuts plasmid with RE, Cuts human DNA with same RE, joins the 2 with DNA ligase -> recombinant DNA plasmids; transfects E.Coli w/reDNA plasmids, detect E.Coli colonies that produce human insulin -> production of insulin (through asexual means)
Genomic library
Collection of all genes in a certain organism; different pieces represent entire genome of organism; All DNA is out and isolated, cut up, inserted into cloning vector at random (plasmid or phage)
DNA Probe
single strand of DNA with a starting DNA; used to investigate part of gene, sythesize base sequence and make it radioactive -> Hot Probe
Hot Probe
radioactive DNA probe; some sequence as a gene of interest; used to make a genomic library
Polymerase Chain Reaction; amplifies small amount of DNA -> automated process using probe -> replication -> 2 molecs of DNA; makes copies of a targeted DNA sequence; requires DNA Polymerase and nucleotides
Restriction fragment length polymorphism (many shapes and sizes)
Determine the sequence and map for every gene in an organism; to determine AA sequence in proteins; can ID all mutations
ID-ing every active region in every protein made by an organism or cell type; can design drugs to inhibit or activate specific target protein
recombinant DNA (rDNA)
rDNA; contains DNA from 2 or more different sources
DNA ligase
enzyme needed to introduce foreign DNA into vector DNA; seals DNA into an opening created by the restriction enzyme
Ways to clone a segment of DNA
Recombinant DNA technology and Polymerase Chain Reaction (PCR)
all the genetic information of an individual or a species
Human Genome Project Goals
construct a map that shows the sequence of base pairs AND GENES along our chromos
binding sites
promoter and operator genes
What are the 3 levels in gene regulation in Eukaryotes?
Transcription, translation, post-translation
inactive enzyme -> active enzyme -> protein; protein kinase control
What are the 3 types of Cell differentiation?
Fatal development, cell maturation, tissue/organ regeneration and repair (liver, ligaments)
Fatal Development
x-chromo inactivation or tissue/organ specificity
Cell Maturation
happens in bloodcells: DNA - destroyed, microphage
Go (G-knot)
in the Cell Cycle, is the terminal differentiation - no more cell division; occurs during mitosis
Cell Cycle
Mitosis, G1 (gap phase 1), DNA synthase, G2 (gap phase 2)
Gene synthesis
positive control
What are the 3 classes of hormones?
Proteins (Ex: Endorphins), Amines (Ex: Adrenaline), Steriods (Ex: Testosterone, from cholesterol at transcriptional level)
Signal transduction
adrenaline binds to plasma membrane; converts ATP --> cAMP
What do hormones do?
Affect gene regulation through transcription
8 Homeotic Genes (HOX)
master regulators that control transcription factors (basically, which parts go where); all contain homeobox, a 180 base pairs protein binding site, sequence of DNA
What are the 3 causes of cancer?
Radiation, Chemicals, Viruses
What are properties of Cancer Cells?
loss of growth control (don't know when to stop in response to stop signals), metastasis (not supposed to go), "immortality" (keep dividing)
Cells go where they are not supposed to go
DNA sequences at the tip of a chromosome; everything your cells divide, the telos get shorter and eventually stop dividing; in cancer cells the telo's don't divide; in normal cells they become shorter (for daughter cell)
Mendalian Inheritance
sexual reproduction; when you cross heterozygote and end up with a homozygous recessive gene Aa x Aa --> 1/4 aa
Somatic Inheritance
Cellular division: if mutation, causes cancer;
normal cell ---(mutation)---> cancer cell
Tendency for mutation to be expressed; actual/predicted
Mutation can "turn on/off" an oncogene and convert normal cell to a cancer cell by a mutation; needed to cause cancer; some cells survive infection; viral DNA integrates
Tumor Suppressor Genes (TSG)
cause apoptosis; Code for proteins that help kill cancer cells or prevent them from dividing; Ex: Rb (RetinolBlastoma) and p53; in breast cancer genes are BRCA1 and BRCA 2
Protein kinase
enzymes that take ATP and stick it on a protein -> protein kinase
program cell death -> cellular suicide (comes from TSG) and activated by p53; cancer cells are fugitives from apoptosis
Viral oncogenes
oncogenes found in tumor viruses; cause human cancers
Breast Cancer
has TSG; mutations of breast genes/proteins increase the risk for other cancers
1st messenger in Fight or Flight (also considered epinephrine)
What are gene defects?
I don't know, but you need to! Look it up! Try the extra readings!
What are problems for the Immune System?
Infections, Cancer, Transplants
a difficulty for the immune system, when there is too little immunity (Ex: AIDS)
hyper immunity
a difficulty for the immune system, when there is too much immunity (Ex: bee sting)
a difficulty for the immune system, when your immune system attacks your own cells (innapropriate difficulty)(Ex: diabetes)
self vs non-self; many pathogens avoid host immune response by "host mimicry"
humoral immunity
type of immune system/response; B-lymphocyte cells are involved and they produce antibodies against antigens in blood, Ex: Toxins; killer T-cells produce protein perforin (which causes cells to break open); and also uses Helper T-lymphocytes
Cell mediated immunity
another type of immune response; Ex: organ tissue transplant, some tumor cells
Killer T-cells
Tc lymphocytes; produce the protein perforin
Helper lymphocytes/T-cells
produce proteins called cytokines (or interleukins) which produce hormones
engulf and dispose/kill cell; produce proteins called cytokines (or interleukins) which produce hormones
Protein that is made from Macrophages and Helper T-lymphocytes; produces hormones; attacks viruses and cancer cells
cell that has the full genetic potential of the organism, including the potential to develop into a complete organism; can divide and differentiate into 1 (or many = poripotent) cell types in the body
many totipotents; in organs like spleen and liver; cells that can divide and differentiate into many cell types
clonal selection
proteins bind to B-lymphocyte cells that have a receptor to recognize foreign enemies; the antigen selects which lymphocyte will undergo clonal expansion and produce more lymphocytes bearing the same type of receptor
A mitogen is a substance that causes a cell to begin dividing.
antigen acts as a?
antigen acts as a mitogen!
:-( something that is seen as a foreign substance, usually a protein or a polysaccharide, so that our immune system to reacts by making antibodies (through B-lymphocytes)
memory B-cells
the few B-cells that don't die off (following division); they have receptors that recognize virus/bacteria
a protein that has 2 Heavy chains, 2 Light chains, 1 codes for Heavy, other for Light; produced in response to the presence of an antigen; each antibody combines with a specific antigen; recombination occurs - every B-cell has different genes and DNA
Structure of an antibody
Heavy & Light chains each have: V=variable region (700), C=Constant region (5), J=joining region (2)
has 1 Heavy chain and 1 Light chain (70 million different possible antibody's can be made)
cells that make antibodies and delete part of DNA
:-) only work against BACTERIA (not viruses); produced to counter an antigen by B-lymphocytes
Probability of spontaneous mutations; 10^-12 is the resistance to both antibodies, (so use a combination of treatments!); become resistant through MUTATIONS, which occur randomly
Resistance Transfer Factor
Resistance Transfer Factor: has many genes for antibiotic resistance
What is Dr. Green's favorite organism?
The virus lamdaphage (which integrates)
reverse transcriptase
enzyme in HIV, copies RNA --> DNA in a cell, which then becomes stable component in cell
temperate phage
phage that is passive or lysogenic
Virulent phage
type of phage that ??
Lysogenic cells
Bacteriophage in which the virus incorporates its DNA into that of a bacterium
Pox Virus
the only virus that doesn't integrate; causes smallpox disease
attenuated virus
a virus grown in another host (cultured) and is then introduced into a human because it is no longer fatal/too harmful
Herpes virus (I and II)
Ex: shingles, DNA integrates in neurons, becomes latent (silent) like lamda; when it infects a nerve cell, it doesn't die
DNA Tumor Viruses
integrates, circular DNA, Ex: SV40 and Polyoma
type of RNA virus; 3 strains, each needs a different antibody; virulent; usually causes stomach yeast?
type of RNA virus; pandemic in 1918-19 killed 20 million people; has a high frequency of recombination and very different strains of viruses; permits years of change before infecting humans
Retrovirus family
type of RNA virus; Ex: HIV and Leukemia; all possess reverse transcriptase; all can integrate copied RNA and DNA (take out and replicate years later); most do not kill host cells (except HIV); have oncogenes; in DNA synthesis RNA --> DNA --> RNA --> Protein
HIV virus
avoids human immune system; mutates with high frequency or recombination; virus weakens and kills host immune system since T-lymphocytes and macrophages are sensitive to HIV; spreads via cell fusion; virus integrates into cell DNA
continuous DNA synthesis
template strand on outside
discontinuous DNA synthesis
lagging strand, breaking down
Hershey-Chase experiment
isolated T-phage, found only phosphate in DNA cells
Messelson and Stahl
DNA replicates semiconservatively
thyamine dimer
thyamine's for a dimer bulge (an example of DNA damage); DNAase cuts out t-dimer; DNApolymerase fix's gap and fills enzyme
mutagen; gets in the way of DNA repair
benign tumor
when a cell mass doesn't metastasize (cancerous they do metastasize)
heterogeneous nuclear; trying to leave nucleus (through spliceosome); in eukaryotes; DNA -> hnRNA -> mRNA -> Protein
What is the start codon?
AUG (codes for methyamine)
How many bases are necessary to code for a protein with 50 AA's?
153. (need 50 codons x 3 = 150 + 3 stop codons)
What is the relationship between codons, Amino Acids, and bases?
3 bases = 1 codon = 1 amino acid
How many genes does Dr. Green think humans have?
About 30,000 human genes
Prokaryote (bacteria and viruses)
has small RNA processing; no organized chromatin
has big RNA processing; yes organized chromatin
enzyme that cuts a protein;
Fight or Flight
produces ATP/energy
Theory of endosymbiosis
Chloroplast and mitochondria were once free living bacteria; structure:
(1) DNA (small circular DNA, no chromatin, histones, chromosomes, or mitosis)
(2) Ribosome structure (like bacteria)
(3) Protein Synthesis (sensitive to antibodies, Ex: Strep); Endosymbiosis; Can't grow or isolate chromosomes or mitochondria because some genes moved to the nucleus DNA
What is the evidence that we all have a common origin?
Metabolic Pathways (glycogen, krebs cycle, oxidative phosphylations via protein gradient); Universal Genetic Code/Protein Synthesis; the cell
Union between different species
Hemoglobin (Gene Family)
B has 146 Amino Acids; Probability = (1/20)^n x f, n = # of identical AA's; Gene duplication and independent mutation causes new genes
have lots of stop signals, they are expressed, proteins aren't produced
Gene Duplication
1 gene duplicated to make 2 (at site where DNA Polymerase stops replicating)
movement of genes; transposons that pick up genes and move them to other sites; explains alpha and beta on different chromosomes; uses transduction; leads to creation of new genes
Protein enzymes (name some)
protein kinase, active transporters, ATP synthase
region of a protein that has 1 function; 1 EXON = 1 DOMAIN
1 Exon = 1 Domain; code for a small portion of protein (region; exons can duplicate, move (translocation) to new locations; binds ATP on protein enzyme
Fruit flies: how many genes
about 600 genes identified in a fruit fly are nearly identical to humans that can cause disease
Different enzymes have same domains (list some)
RNA Polymerase; ATP synthase; Protein Kinase; transport proteins
For each Amino Acid, the probability is (1/20)^n, n = # of AA that match
How many bases code for 10 AA?
10 x 3 = 30 (domain); 10 x 3 + 3 = 33 (WHOLE protein of end of protein; chance of (1/4)^__30__ = probability of having 30 identical bases in a sequence
Viruses are not ?
Virus acts as a ?
mitogen (--> mitosis --> secreting antibodies); clonal selection model
SRY Gene
appears female but has y-chromosome
How are bacteria different from eukaryotic cells?
Bacteria do not possess a nucleus
What is a cytocrome and what does it do?
A cytocrome is a protein in a human cell that catalyzes redox reactions
How many different Amino Acids are used as building blocks for proteins found in all living things?
20 Amino acids total
What are the characteristics of a hydrophilic proteins?
hydrophilic: polar and charged --> soluble in water
What are the characteristics of a hydrophobic protein?
hydrophobic: non-polar
What does the lysosome do?
Lysosome: degradation of detnatured cellular proteins
What does the mitochondria do?
mitochondria synthesizes ATP by using the E-TC (in animals)
What does the nucleolus do?
Nucleolus sythesizes ribosomal RNA
What synthesizes ALL proteins?
what modifies proteins by adding carbohydrates?
golgi apparatus
What region on an enzyme does a substrate bind to?
active site
How do enzymes catalyze biochemical reactions?
By lowering the activation energy of the substrate
What is the "secret of Life"?
The ability to drive chemical reactions that are called endergonic reactions; Ex: synthesis of energy
What is glycolysis?
The anaerobic oxidation of glucose to pyruvate
Where are glycolysis enzymes?
Outside of mitochondria's outer membrane - cytosol
Where does the Krebs cycle take place?
in the matrix in the innermost mitochondrial compartment
Where does the E- Transport CHain take place?
Cristae folds across the inner membrane in mitochondria
Where are protons produced by the E- transport chain?
intermembrane space of mitochondria
Where is ATP synthase?
inner membrane of mitochondria
What 2 stages of meiosis give rise to genetic diversity?
Prophase I (chromosomes pair up randomly) and Metaphase I (chromosomes line up at metaphase point)
What is the probability that a couple with 2 sons will have another son for their 4th child?
An enzyme has 4 identical polypeptide subunits, all called a. In a person who is heterozygous for the gene that codes for this enzyme, what fraction of the enzyme molecules would be comprised of 4 non-mutated a subunits, thus being active enzyme?
(1/2)^4 = 1/16, since the probability of being good is 1/2
What is semi-conservative DNA replication?
One parental strand goes to each of the 2 DNA molecules
Draw a base sequence that would be attacked by UV light
Thymine dimer: CATTGAC
What is the code for a start codon?
Draw a thymine dimer!
Why is caffeine a suspected carcinogen?
Caffeine causes mutations
What are carcinogens?
Chemicals that cause cancer
What happened in the Hershey-Chase Experiment?
DNA, not proteins, was shown to be the genetic material
What does E.Coli need to grow?
E.Coli needs glucose and salts
What do auxotrophs need to grow?
Something additional - arginine
How many bases (including start and stop signals), are necessary for the DNA to code for the protein (Ex: protein has 30 amino acids)
93: 30 x 3 + 3 = 93
What do tRNA's do?
tRNA carries amino acids to the ribosomes for protein synthesis
What type of gene cells contain introns?
What type of gene cells contain exons?
Eukaryotes AND prokaryotes
Eukaryotic DNA is ___________ into _____, which is then spliced into ____ by __________, which are unique enzymes because they contain RNA
Eukaryotic DNA is transcribed into hnRNA, which is then spliced into mRNA by spliceosomes, which are unique enzymes because they contain RNA
What is unique about spliceosomes?
spliceosomes contain RNA
How many genes code for Hemoglobin, a2B2?
2: 1a + 1B
What 2 regulator genes are expressed in the lactose operon?
promoter and operator genes
What binds to RNA polymerase?
What binds to the repressor protein?
When is the lactose operon induced?
Lactose operon is turned on when (1) lactose binds to the repressor protein and (2) the concentration of glucose is very low
A high concentration of _____ is caused by a low concentration of ______
A high concentration of cAMP is caused by a low concentration of glucose (low glucose --> high cAMP)
What does cAMP bind to when it is present in high concentrations?
cAMP binds to the proteins CRP and CAP, forming the CRP-CAP Complex which turns the lactose operon on
Where would a restriction enzyme cut the DNA sequence:
What creates sticky ends in DNA?
When a restriction enzyme cuts human DNA and E.Coli DNA and all of the resulting fragments are joined together
What is an example of an episome?
the F factor
What 2 states can the F factor replicate into?
autonominously and integrated
When an episome is autonomously integrated what is the result?
it's genes can be transferred in a high frequency, leading to male E.Coli becoming super males since they can transfer their genes to females quickly
What are plasmids?
Plasmids are episomes that have lost their ability to integrate
What is the 1st messenger in "fight or flight"?
adrenaline = 1st
What is the 2nd messenger in "fight or flight"?
cAMP = 2nd
What enzyme does cAMP activate?
How does protein kinase facilitate post-translational control?
Protein kinase adds a phosphate group from cAMP to another enzyme, thereby activating the enzyme
What regulates gene expression at the level of transcription?
Steriod hormones
In what stage of the cell cycle does the most extreme shutdown of gene expresssion occur?
What does cAMP activate in E.Coli AND eukaryotes?
What technique is used to analyze DNA samples for restriction fragment length polymorphisms?
Gel Electrophoresis
What does RFLP stand for?
Restriction Fragment Length Polymorphisms
Why don't base pair mutations always cause changes in protein primary structure?
(1) the mutation may reside in introns and (2) redundancy in the genetic code
Why do viruses, carcinogens, and radiation cause cancer?
They cause mutations
What does the activation of oncogenes do?
Oncogenes cause somatic cells to develop into cancer cells
How many oncogenes does every normal human cell have?
100 oncogenes
When ______ are inactivated by mutations, there is a high incidence of cancer
Tumor Supressor Genes
What is an example of a Tumor Suppressor Gene?
What is a common first step that results in a series of biochemical reactions that convert a normal cell into a cancer cell?
activation of protein kinase
What do telomeres do in normal cells but not in cancer cells?
In a normal cell, telomeres become shorter every time the cell divides
What is responsible for rejection of kidney transplants?
cell-mediated immunity
What is responsible for producing antibodies against viruses and bacteria in the blood?
humoral immunity
"Clonal selection" in antibody production is when?
foreign antigens act as mitogens when they bind to B-lymphocytes
What is autoimmunity and give an example:
When the immune system starts attacking it's own cells; Ex = diabetes
What is carried out by Retroviruses when they establish a latent (non-virulent) infection?
Retroviruses integrate their own DNA into the host's DNA
THe mutation frequency for penicillin resistance and streptomycin resistance is 10^-5 and 10^-6. What is the frequency of resistance for both together? How many bacteria must be present in order to find one that is resistant to both antibodies?
10^-11; 10^11
How does the influenza virus avoid host immunity?
What is an attenuated virus? What is an example?
A virus that was grown in an animal cell and is no longer pathogenic to man; Ex: Sabin's vaccine
Why don't antibiotics stop viral replication?
Viruses are not bacteria, and antibiotics only stop bacteria
How does p53 in humans prevent cancer?
p53 causes damaged cells to commit apoptosis
What is Polymerase Chain Reaction used for?
PCR: Making billions of copies of DNA
What did the blocking of Nitric Oxide in mice result in?
violence, kill, rape other cage mates
What do mutations in the CKR5 gene do?
CKR5 makes people resistant to infections by HIV or AIDS virus
What is the big risk in cloning mice?
They grew to be very obese