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Fundamentals I Test 4 Pittler
Flash Cards for Dental School
123
Microbiology
Professional
09/23/2010

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Term
Plants which consistently have offspring with same trait as parent are ___.
Definition
True breeding or Homozygous
Term
What is the name for crossing true breeding plants with two distinct forms of a trait?  What is the result of this?
Definition
Monohypbrid Cross (Heterozygous): progeny only show one form of the trait
Term
Describe a test cross.
Definition
Plant with recessive trait is crossed with plant of unknown genotype.
Term
Describe the progeny of a monohybrid cross.
Definition

1/4 Dominant - True breeding; 1/2 Dominant - Not true breeding; 1/4 recessive

3:1 dominant to recessive

Term
What are the two parts of the law of probability?
Definition

1. probability that multiple independent events will occur together is the product of their chances of happening separately

2. chance an event can occur in multiple independent ways is the sum of the individual chances

Term
What state that each organism possesses two distinct separable units (alleles) for each trait inhetited from each parent?
Definition
Law of segregation
Term
What state that each organism possesses two distinct separable units (alleles) for each trait inhetited from each parent?
Definition
Law of segregation
Term
What is another name for Mendel's units or elementum?  It is also defined as versions of the same gene that differ in DNA sequence at one or more sites.
Definition
Alleles
Term
What indicates the combination of alleles present in an organism?
Definition
Genotype: Homozygous (same alleles) & Heterozygous (different alleles)
Term
What indicates the trait observed?
Definition
Phenotype
Term
What is the most common phenotype called?
Definition
Wildtype; wildtype allele=most frequent allele
Term
What indicates the patterns with which the mutant phenotype is associated? What are the three most common types?
Definition
Mode of Inheritance; Autosomal Recessive, Autosomal Dominant, & X-linked Recessive
Term
What mode of inheritance is described by these characteristics? Heterozygotes exhibit affected phenotype, males & females equally affected and may transmit the trait, and affected phenotype does not skip generations.
Definition
Autosomal Dominant Inheritance
Term
What mode of inheritance is characterised by these statements?  Heterozygotes carry allele but don't exhibit it, males & females equally affected and may transmit the trait, and may skip generations.
Definition
Autosomal Recessive Inheritance
Term
What states that two genes on different chromosomes segregate their alleles independently?
Definition
Law of Independent Assortment (inheritance of one allele doesn't influence inheritance of another)
Term
What is a symbolic representation of family relationships and inheritance of a trait?
Definition
Pedigrees
Term
What is a structure that consists primarily of DNA & proteins that are duplicated & transmitted during mitosis or meiosis?
Definition
Chromosomes
Term
Distinguish between Heterochromaticn & Euchromatin.
Definition

Heterochromatin stains dark, noncoding

Euchromatin stains light, protein coding

Term
What are the three locations you find centrosomes on the chromosome?
Definition
Metacentric=middle, Acrocentric=close to end, Submetacentric=off center, Telocentric=end
Term
What are the two arms of a chromosome?
Definition
P arm = short arm & Q arm = long arm
Term
What is the basic unit of chromatin?  What does it consist of?
Definition
nucleosome; 146bp DNA & 8 histones
Term
Which histone helps compact nucleosome into 30nm fiber?
Definition
H1
Term
What is a critical determinant of chromatin structure?
Definition
Histone tails; methylation & acetylation leads to genomic imprinting & regulation
Term
What does a normal karyotype consist of?
Definition
23 diploid chromosomes; 46 total chromosomes
Term
What is the term for a cell missing a single chromosome or having an extra one?
Definition
Anueploid
Term
What is the term for cells that contain a normal chromosome constitution?
Definition
Euploid
Term
How are chromosomes ordered on a Karyotype?
Definition
by size & centromere position
Term
What states that modifications of the histone tails act as marks that can be read by other proteins to control the expression or replication of chromosomal regions?
Definition
Histone Code Hypothesis
Term
What is described as heritable changes not caused by mutation in the DNA?
Definition
Epigenetics
Term
What is genomic imprinting?
Definition
Each parent passes on a gene for a trait, but only one is expressed.  The other is "imprinted" ie. Barr Bodies
Term
What disease is caused by a defect in imprinting & causes kidney tumors in children?
Definition
Wilms Tumor
Term
What leads to gene silencing?
Definition
Methylation of C residues in CpG island
Term
What disease is caused by a DNA methylation problem?
Definition
Rett Syndrome
Term
What is at the tips of chromosomes and what sequence do you find here?
Definition
Telomeres; TTAGGG
Term
What chromosomal part is found between the protein-rich areas and the telomeres?
Definition
Subtelomeres
Term
T/F Subtelomeres do include some protein-coding genes?
Definition
True
Term
What is the location where spindle fibers attach to the centromere?
Definition
Kinetochore
Term
What technique uses DNA probes that are complimentary to specific base sequences?
Definition
FISH (Flourescence in situ Hydrogenation)
Term
What subdiscipline within genetics focuses on chromosome variations?
Definition
Cytogenetics
Term
What disease is a trisomy of chromosome 21?  What about XO and XXY?
Definition
Trisomy 21=Down's, XO=Turner (female), XXY=Klinefelter (male)
Term
What are the three most common trisomy chromosomes?  What do they have in common?
Definition
13 (Patau), 18 (Edward), & 21(Down); have lowest gene densities
Term
What is the term for an extra chromosome set? What causes this?
Definition
Polyploidy; 2 sperm fertilizing one egg or haploid sperm fertilizing diploid egg
Term
What is the term for having a segment of the chromosome reversed?
Definition
Inversion
Term
What is the term for two chromosome arms exchanged in part or entirely?
Definition
Translocation
Term
What is a chromosome with identical arms?
Definition
Iso chromosomes
Term
What causes a ring chromosomes?
Definition
Deletion of telomeres
Term
What is a common cause of aneuploidy resulting in a gamete with one extra chromosome & another with one missing chromosome?  How do the results differ between the 1st and 2nd meiotic anaphase division?
Definition
Nondisjunction; 1st - copy of each homolog in gamete & two cells with no copies; 2nd - both sister chromatids in one gamete, one with no copy, and two normal cells (better of the two scenarios)
Term
What does nondisjunction cause?
Definition
euploidy
Term
What is the term for different nonhomologous chromosomes that exchange portions of chromosomes or combined parts?
Definition
Translocation
Term
What describes chromosomes that have a region flipped in orientation compared to wild type chromosomes?  What are the two types?
Definition

Inversion

Paracentric: inverted region doesn't include centromere

Pericentric: inverted region includes centromere

Term
In what two ways can mutation occur at the molecular level?
Definition
1. Substitutin one DNA base for another  2. Adding or deleting bases
Term
The mutation of what protein prevents people from being infected with HIV?
Definition
CCR5
Term
Does mutation refer to genotype or phenotype?  What about mutant?
Definition
Mutation=Genotype     Mutant=Phenotype
Term
What is a mutation that does not alter the phenotype?
Definition
Polymorphism
Term
T/F A mutatuion produces individuals with variant phenotypes who are better able to survive in a specific environment.
Definition
True
Term
What type of mutation is limited to an individual and not transmitted to offspring?
Definition
Somatic Mutations
Term
What type of mutation have the possibility of transmission to offspring?
Definition
Germline Mutations
Term
Describe the mutation in red blood cells that leads to Sickle Cell Anemia.
Definition
T in DNA anti-sense strand is changed to A = Glu is changed to Val
Term
What is the result of a beta hemoglobin mutation that results in too few protein molecules?
Definition
Thalessemia (homozygous mutation has more severe phenotype than heterozygous)
Term
What comprises 60% of bone & cartilage?  What is it's structure?
Definition
Collagen; two α1 helices and one α2 helix
Term
Mutation in what protein is responsible for Alzheimer disease?  Where is this protein found & what is it's function?
Definition
Presenilin 1; anchored in Golgi membrane, monitors beta amyloid usage (accumulation placques form)
Term
What are the four main characteristics of Spontaneous mutation?
Definition
1. De novo or new  2. Not caused by exposure to known mutagen  3. Errors in DNA replication  4. DNA bases have slight chemical instability
Term
Spontaneous mutations can produce slightly changed ____s which cause problems for the enzymes that are trying to recognize the sequence.
Definition
tautomers
Term
What is the mutation associated with Familial hyperchlesterolemia?
Definition
Deficient LDL receptors
Term
What mutation is associated with Hemophilia A?
Definition
absent or deficient Factor VIII protein
Term
What three things is spontaneous mutation rate dependent on?
Definition
1. Size dependence  2. Sequence dependence  3. Hot spots
Term
T/F  Most mutations are in coding regions of genes.
Definition
False; most are in noncoding regions
Term
What are the three mutational hot spots, and what is their source?
Definition

1. Short Repetitive Sequence: pairing of repeats may interfere w/replication or repair enzymes

2. Palindromes: associated w/insertions or deletions

3. Duplications of Larger Regions: mispairing during meiosis

Term
What are two major causes of insertions or deletions?
Definition
Hairpins & Non-Reciprocal Recombination
Term
What chromosome is effected by alpha thalassemia?  What are the effects of different numbers of this chromosome?
Definition
16; 4=normal, 3=considered normal, 2=mild anemia, 1=severely anemic
Term
What is the term for a chemical that causes mutation?
Definition
Mutagen
Term
What is the term for chemicals that cause cancer?
Definition
Carcinogens
Term
Which mutation inducer causes removal of a DNA base that is replaced with a mismatch pair?
Definition
Alkylating agent
Term
Which mutation inducer addes or deletes a single base?
Definition
Acridine dyes
Term
Which mutation inducer alters base pairs so that A-T replaces G-C or vice versa?
Definition
Mutagenic chemicals
Term
Which mutation inducer deletes a few bases or breaks chromosomes?
Definition
X-rays & other radiation
Term
T/F  Ames is an in vivo test of mutagenicity of a substance using Salmonella bacteria with a mutation in a gene.
Definition
False; in vitro
Term
What amino acid is involved in the mutation used in the Ames test?
Definition
Histidine
Term
Describe the least penetrating radiation exposure.
Definition
Alpha; least energetic, shortest-lived, absorbed by skin; Uanium & radium
Term
Describe the second most penetrating radiation.
Definition
Beta; tends not to harm unless eaten or inhaled; tritium, C-14, & strontium-70
Term
Describe the most penetrating type of radiation.
Definition
Gamma; goes all the way through body, kills cancer cells; plutonium & cesium
Term
Mutations in what types of cells can cause cancer?
Definition
Oncogenes or Tumor Suppressor Genes
Term
What type of mutation is caused by a change of a single nucleotide to one of the other three possible nucleotides?
Definition
Point Mutation
Term
Differentiate between a Transition and a Transversion.
Definition

Transition: Purine replaces Purine or Pyrimidine replaces Pyrimidine

Transversion: Purine replaces Pyrimidine or vice versa

Term
What is a point mutation that exchanges one codon for another causing substitution of an amino acid?
Definition
Missense Mutation (ie. Sickle Cell)
Term
What type of mutation has a change in amino acid from a normal codon to a premature stop codon?
Definition
Nonsense mutation (ie. Becker muscular dystrophy or Ehlers-Danlos)
Term
What type of mutation alters a site where introns would normally be removed from mRNA?
Definition
Splice Site Mutations
Term
What is the term for a particular form of insertion in which identical sequences are found side by side?
Definition
Tandem Duplication
Term
What is the term for a DNA sequence reminiscent of a gene but isn't translated?  Can it be transcribed?
Definition
Pseudogenes; may or may not be transcribed
Term
What phenomena is described as expansion of the triplet repeat and coincident increase in severity of phenotype occuring with subsequent generations?
Definition
Anticipation (ie. Myotonic dystrophy)
Term
T/F  Different mutations may cause the same disorder.
Definition
True
Term
T/F  All mutations impact protein function.
Definition
False; Silent Mutations don't alter AA sequence because they form Synonymous Codons
Term
What type of mutation only produces a phenotype under particular conditions?
Definition
Conditional Mutations
Term
What number of bases can be replaced by Nucleotide & Base Excision Repair?
Definition
Nucleotide: <30     Base: 1-5   (ie. Xeroderma Pigmentosa)
Term
What occurs when enzymes detect nucleotides that do not base pair in newly replicated DNA?  How is it detected?
Definition
Mismatch Repair; Proofreading
Term
What protein monitors repair of damaged DNA?
Definition
p53
Term
What is a group of diseases caused by loss of cell cycle control?
Definition
Cancer
Term
What type of tumer grows in place? What type invades nearby tissues?
Definition
Benign=stationary, Malignant=invasive
Term
T/F  More often cancer-causing mutations occur in somatic cells & is a genetic disease at the whole-body level.
Definition
False; they are usually somatic cells, but it works at the cellular level not the whole-body
Term
Loss of control over what portion of the chromosome can contribute to cancer?
Definition
Telomere
Term
T/F  Germline inherited cancers must have a second mutation in the somatic cell to spark cancer in the body.
Definition
True
Term
What are two unique characteristics of cancer cells?
Definition
Rounder (doesn't adhere to normal cells) & plasma membrane is more fluid
Term
What is secreted by tumor cells that are starved for Oxygen?
Definition
Vascular Endothelial Growth Factor - stimulates capillaries to extend branches toward tumor
Term
Are Proto-oncogenes normal cells or mutated cells?
Definition
Normal
Term
Can oncogenes effect viral & transcribing genes nearby?
Definition
Yes
Term
T/F  Reciprocal translocation produces two different fusion genes.
Definition
True
Term
Is phosphorylation normally present in cancer cells?
Definition
No
Term
What type of gene normally stops cells from dividing?
Definition
Tumor Suppressor Genes
Term
What states that two mutations, one in each copy of the RB gene, are required to cause a phenotypic result?
Definition
Knudson's Two Hit Hypothesis
Term
What is the breast cancer susceptibility gene, and how does it function?
Definition
BRCA1; one mutation is inherited & a second must be acquired at the cellular level
Term
What is described as a change in one gene can compensate for the mutation in another, could be the result of epigenetics?
Definition
Incomplete Penetrance
Term
What are the three environmental impacts of cancer?
Definition
Exposure to carcinogens, Exposure to radiation, and Variation in diet
Term
What type of vegetables can lower cancer risk?
Definition
Cruciferous
Term
What are the 5 treatments for breast cancer?
Definition
Remove tissue, Destroy tissue, Use phenotype to select drug, Use genotype to select drug, Genomic level
Term
What four properties of DNA are most genetic technologies based on?
Definition

1. DNA can be cut at specific sites

2. Different lengths of DNA can be size-separated by electrophoresis

3. Single strand of DNA will stick to its complement

4. DNA can be copied by a polymerase enzyme

Term
T/F  Most recognition sites where restriction enzymes cut are palindromes.
Definition
True
Term
What charge does DNA have?  Describe it's movement on a gel.
Definition
Negative; moves toward positive electrode, shorter lengths move faster
Term
What are the two methods for analyzing the way in which DNA sticks to its complement?
Definition
PCR and Southen Blotting (slow & requires large amount of DNA)
Term
What is a method for producing large quantities of a specific region of DNA from tiny quantities?
Definition
Polymerase Chain Reaction (PCR); requires much less DNA than Southern Blotting
Term
What DNA polymerase can copy DNA?
Definition
Taq DNA Polymerase
Term
What are the possible samples for PCR? Do they have to be pure?
Definition
hospital tissue, single hair, dried blood, mummified tissue, frozen tissue; No-can be pure or impure
Term
What method uses mRNA as a marke of gene expression?  What is it used for?
Definition
Microarrays; measure differences in gene expression between two cell types or to study chromosomal aberrations in cancer cells (diagnose & stage tumors)
Term
What are the problems with microarray analysis?
Definition
Gene expression≠mRNA concentration, Difficult to interpret, Standardization b/w labs, Lots of noise, Lots of genes, Low sample size
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