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Glossary of EFB-307 Genetics, F2009 Exam 2

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L8 - GENE & CHROMOSOME MUTATION FOUNDER MUTATION
FOUNDER MUTATION:
A mutation carried the ancestral founder of a distinct population.
L8 - GENE & CHROMOSOME MUTATION What 7 human conditions have roots in founder mutations?
1. Iron overload
2. Cystic fibrosis
3. Sickle cell disease
4. Blood clots
5. Alcohol toxicity
6. Lactose tolerants
7. Deafness





L8 - GENE & CHROMOSOME MUTATION TRUE/FALSE: There are no advantages to being heterozygous for a founder mutation.
FALSE
L8 - GENE & CHROMOSOME MUTATION What are the 3 main types of mutations?
1. Single-gene mutations
2. Chromosome mutations
3. Genome mutations

L8 - GENE & CHROMOSOME MUTATION SINGLE-GENE MUTATION
SINGLE-GENE MUTATION:
Relatively small change in DNA structure that occurs within a specific gene.
L8 - GENE & CHROMOSOME MUTATION What 2 sites in a gene can a SINGLE-GENE MUTATION alter?
1. Promoter
2. Transcriptional unit
L8 - GENE & CHROMOSOME MUTATION CHROMOSOME MUTATION
CHROMOSOME MUTATION:
Change in the chromosome structure.
L8 - GENE & CHROMOSOME MUTATION GENOME MUTATION
GENOME MUTATION:
Change in the chromosome number.
L8 - GENE & CHROMOSOME MUTATION ALLELE
ALLELE:
One of the different forms of a gene that exists at a single locus.
L8 - GENE & CHROMOSOME MUTATION LOCUS
LOCUS:
Location of a gene on the chromosome.
L8 - GENE & CHROMOSOME MUTATION MUTATE
MUTATE:
To change.
L8 - GENE & CHROMOSOME MUTATION In what 2 ways are alleles generated?
1. Recombination of functional gene domains
2. Gene mutation
L8 - GENE & CHROMOSOME MUTATION What are the 3 gene-altering effects on base (A,C,G,T) generation?
1. Deletions
2. Additions
3. Substitutions

L8 - GENE & CHROMOSOME MUTATION WILD-TYPE (wt)
WILD-TYPE (wt):
Designated standard allele.
L8 - GENE & CHROMOSOME MUTATION FORWARD MUTATION
FORWARD MUTATION:
Any change away from the wild-type allele.
L8 - GENE & CHROMOSOME MUTATION REVERSE MUTATION
REVERSE MUTATION (REVERSION/BACK MUTATION):
Any change back to the the wild-type allele.
L8 - GENE & CHROMOSOME MUTATION IGF1 allele encodes what?
IGF1 allele encodes an insulin-like growth factor.
L8 - GENE & CHROMOSOME MUTATION IGF1 allele affects what?
IGF1 allele is the major determinate of dog size.
L8 - GENE & CHROMOSOME MUTATION IGF1 allele is present and absent in what?
IGF1 allele is present in small dog breeds. IGF1 allele is absent in giant dog breeds.
L8 - GENE & CHROMOSOME MUTATION HAPLOTYPE
HAPLOTYPE:
A specific combination of alleles/sequence variations that can be inherited together.
L8 - GENE & CHROMOSOME MUTATION POLYMORPHISM
POLYMORPHISM:
A sequence variation at a given chromosomal location that is common in a population.
L8 - GENE & CHROMOSOME MUTATION SINGLE NUCLEOTIDE POLYMORPHISM (SNP)
SINGLE NUCLEOTIDE POLYMORPHISM (SNP):
A single-basepair variation in a DNA sequence that is common to a population.
L8 - GENE & CHROMOSOME MUTATION TRUE/FALSE: Size is a quantitative trait.
TRUE
L8 - GENE & CHROMOSOME MUTATION IGF1 allele consists of what haplotype?
SNP (single-nucleotide polymorphism).
L8 - GENE & CHROMOSOME MUTATION What are the 6 agents of gene mutations?
1. DNA replication errors
2. Reactive cellular metabolites
3. Chemicals
4. High-energy radiation
5. Mobile genetic elements
6. Viruses




L8 - GENE & CHROMOSOME MUTATION What are the 3 steps to gene mutation?
1. Mutagenic agents/events
2. Premutational gene damage
3. Repair-system activity

L8 - GENE & CHROMOSOME MUTATION What 3 agents of gene mutation can have no repair-system activity take place?
1. DNA replication errors
2. Mobile genetic elements
3. Viruses

L8 - GENE & CHROMOSOME MUTATION In what 3 ways does the genetic repair-system deal with premutational damage?
1. Cuts out damaged DNA segment; replace with DNA generated from template
2. Reverses damage
3. Bypasses lethal replication block by accepting mutated base

L8 - GENE & CHROMOSOME MUTATION What is the result of no repair-system activity on premutational damage caused by DNA replication errors?
Expansion of small repeat.
L8 - GENE & CHROMOSOME MUTATION What is the result of no repair-system activity on premutational damage caused by mobile genetic elements or viruses?
DNA insertion.
L8 - GENE & CHROMOSOME MUTATION What is the result of premutation damage being cut out and replaced with template DNA by the repair-system?
No mutation.
L8 - GENE & CHROMOSOME MUTATION What is the result of premutational damage reversal by the repair-system?
No mutation.
L8 - GENE & CHROMOSOME MUTATION What is the result of the repair-system's attempt to bypass a lethal replication block by accepted a mutated base?
Base-pair substitution.
L8 - GENE & CHROMOSOME MUTATION POINT MUTATION
POINT MUTATION: Change in a single basepair via base substitution. 5'-AACGCTAGATC-3' becomes 5'-AACGCGAGATC-3'
L8 - GENE & CHROMOSOME MUTATION TRANSITION
TRANSITION:
Change of a pyrimidine (C,T) into another pyrimidine (C,T)
-or-
Change of a purine (A,G) into another purine (A,G).


L8 - GENE & CHROMOSOME MUTATION TRANSVERSION
Change of a pyrimidine (C,T) to a purine (A,G) or vice versa.
L8 - GENE & CHROMOSOME MUTATION PYRIMIDINE BASES
PYRIMIDINE BASES:
C, T
L8 - GENE & CHROMOSOME MUTATION PURINE BASES
PURINE BASES:
A, G
L8 - GENE & CHROMOSOME MUTATION TRUE/FALSE: Transitions are more common than transversions.
TRUE
L8 - GENE & CHROMOSOME MUTATION What is the consequence of addition/deletion mutations?
Frameshift
L8 - GENE & CHROMOSOME MUTATION What are the 3 consequences of base substitution mutations?
1. Silent
2. Missense
3. Nonsense

L8 - GENE & CHROMOSOME MUTATION NONSENSE MUTATION
NONSENSE MUTATION:
Produces a premature stop codon.
L8 - GENE & CHROMOSOME MUTATION SUPPRESSOR MUTATION
SUPPRESSOR MUTATION:
Produces a mutant tRNA anticodon that suppresses codon mutations.
L8 - GENE & CHROMOSOME MUTATION Thymine residues along a DNA backbone, irradiated with UV light, form what?
Thymine photodimer.
L8 - GENE & CHROMOSOME MUTATION SLIPPAGE MUTATION
SLIPPAGE MUTATION:
When DNA replication slips at repeated bases and either adds extra nucleotides or misses adding needed nucleotides.
L8 - GENE & CHROMOSOME MUTATION What are 2 diseases caused by trinucleotide repeats?
1. Huntington disease (HD)
2. Fragile X syndrome (FRAXA)
L8 - GENE & CHROMOSOME MUTATION TRINUCLEOTIDE REPEAT (TNRE)
TRINUCLEOTIDE REPEAT (TNRE):
Phenomenon where a sequence of 3 nucleotides increases from one generation to the next.
L8 - GENE & CHROMOSOME MUTATION TRUE/FALSE: In individuals without TNRE mutations, there are still regions of the chromosome with trinucleotide repeats.
TRUE
L8 - GENE & CHROMOSOME MUTATION What 2 conditions occur in persons with TNRE disorders?
1. Trinucleotide repeats increase above a certain critical size.
2. Trinucleotide repeats become prone to frequent expansion.
L8 - GENE & CHROMOSOME MUTATION What protein base is most susceptible to expansion by TNRE disorders?
CAG (glutamine).
L8 - GENE & CHROMOSOME MUTATION What is the effect of glutamine expansion in individuals with TNRE disorders?
Proteins include long chains of glutamine that cause them to aggregate together.
L8 - GENE & CHROMOSOME MUTATION TRUE/FALSE: Protein aggregation in individuals with TNRE disorders is not correlated to the progression of their disease.
FALSE
L8 - GENE & CHROMOSOME MUTATION What are the 2 features of TNRE disorder inheritance?
1. Disorder severity worsens in future generations (ANTICIPATION)
2. Disorder severity is dependent on whether it is inherited from the father or the mother.
L8 - GENE & CHROMOSOME MUTATION ANTICIPATION
ANTICIPATION:
When genetic disorder severity worsens in future generations.
L8 - GENE & CHROMOSOME MUTATION In HD, the TNRE worsens if inherited from which parent?
Father
L8 - GENE & CHROMOSOME MUTATION In myotonic muscular dystrophy, the TNRE worsens if inherited from which parent?
Mother
L8 - GENE & CHROMOSOME MUTATION TRUE/FALSE: The genetic origins of TNRE are well-understood.
FALSE
L8 - GENE & CHROMOSOME MUTATION What is the most common cause of gene mutation?
DNA replication errors
L8 - GENE & CHROMOSOME MUTATION TRUE/FALSE: DNA replication is inherently inaccurate.
TRUE
L8 - GENE & CHROMOSOME MUTATION TRUE/FALSE: Cancers develop faster in cells that divide quickly.
TRUE
L8 - GENE & CHROMOSOME MUTATION The inherent inaccuracy of DNA replication is advantageous to what?
Viruses
L8 - GENE & CHROMOSOME MUTATION MUTATION RATE
MUTATION RATE:
Likelihood that a gene will be altered by a new mutation.

Expressed as (# of new mutations in a given gene) per generation.


L8 - GENE & CHROMOSOME MUTATION What is the range of mutation rates per generation?
10-5 to 10-9 per generation.
L8 - GENE & CHROMOSOME MUTATION Why is the mutation rate for a given gene inconsistent?
Mutation rates can be increased by the presence of mutagens.
L8 - GENE & CHROMOSOME MUTATION TRUE/FALSE: Mutation rates for a given gene are constant.
FALSE
L8 - GENE & CHROMOSOME MUTATION TRUE/FALSE: Mutation rates vary substantially between species.
TRUE
L8 - GENE & CHROMOSOME MUTATION TRUE/FALSE: Mutation rates vary substantially between different strains of the same species.
TRUE
L8 - GENE & CHROMOSOME MUTATION HOT SPOTS
HOT SPOTS:
Locations within the chromosome that are more susceptible to mutation.
L8 - GENE & CHROMOSOME MUTATION What are 2 reasons why some genes will mutate faster than other genes in the same individual?
1. Some genes are larger than others, providing more space for mutations.
2. Some genes are located at hot spots on the chromosome.
L8 - GENE & CHROMOSOME MUTATION MUTATION FREQUENCY
MUTATION FREQUENCY:
(number of mutant alleles of a specific gene)
divided by
(total number of genes in a population)


L8 - GENE & CHROMOSOME MUTATION What are the 2 classes of gene mutation in multicellular eukaryotes?
1. Somatic
2. Germinal
L8 - GENE & CHROMOSOME MUTATION SOMATIC MUTATION
Mutation in vegetative cells involved in aging/cancers, not passed on to future generations.
L8 - GENE & CHROMOSOME MUTATION GERMINAL MUTATION
GERMINAL MUTATION:
Source of new alleles that can be passed on to future generations.
L8 - GENE & CHROMOSOME MUTATION If 1 million bacteria were plated and 10 were mutant, what would be the mutation frequency?
10/1,000,000 = 1 in 100,000 = 10-5
L8 - GENE & CHROMOSOME MUTATION What type of mutation creates patches of mutated cells?
Somatic
L8 - GENE & CHROMOSOME MUTATION GENETIC MOSAIC
GENETIC MOSAIC:
Organism composed of patches of mutated cells.
L8 - GENE & CHROMOSOME MUTATION What are the three types of phenotypically expressed mutations?
1. Loss-of-function
2. Gain-of-function
3. Silent

L8 - GENE & CHROMOSOME MUTATION What is the inheritance character of loss-of-function mutations?
Recessive/Incompletely dominant
L8 - GENE & CHROMOSOME MUTATION What is the inheritance character of gain-of-function mutations?
Dominant/Codominant
L8 - GENE & CHROMOSOME MUTATION TRUE/FALSE: Gain-of-function mutations are rare.
TRUE
L8 - GENE & CHROMOSOME MUTATION What are the 2 instances where silent mutations may cause phenotypic changes?
1. Disrupts RNA processing
2. Disrupts gene expression
L8 - GENE & CHROMOSOME MUTATION RADIATION BREEDING
RADIATION BREEDING:
The practice of exposing crops to gamma radiation to produce beneficial mutations.
L8 - GENE & CHROMOSOME MUTATION What is an example of a loss-of-function mutation?
"Ruby red" grapefruit
L8 - GENE & CHROMOSOME MUTATION How many crop varieties have been developed by radiation mutation?
Over 2,000.
L8 - GENE & CHROMOSOME MUTATION What type of mutation causes cancer?
Somatic
L8 - GENE & CHROMOSOME MUTATION What 3 objectives must cancerous cells meet before they can take over a body?
1. Acquire rapid cell division (forms a tumor)
2. Acquire a new blood supply
3. Acquire ability to invade other tissues (metastasis)

L8 - GENE & CHROMOSOME MUTATION METASTASIS
METASTASIS:
The ability of cancerous cells to move to and invade other tissues.
L8 - GENE & CHROMOSOME MUTATION PROTO-ONCOGENES
PROTO-ONCOGENES:
Turn on cell growth/division, normal developmental function genes.
L8 - GENE & CHROMOSOME MUTATION TUMOR SUPPRESSOR GENES
TUMOR SUPPRESSOR GENES:
Suppress cell growth/division.
L8 - GENE & CHROMOSOME MUTATION What are the 2 possible results of a 2nd mutation in a gene that is already mutant?
1. Dead/malfunctioning cell (aging)
2. Cancerous cell
L8 - GENE & CHROMOSOME MUTATION ONCOGENE
ONCOGENE:
Mutant proto-oncogene whose dominant path is to become a cancer cell and whose recessive path is to acquire a second mutation.
L8 - GENE & CHROMOSOME MUTATION In what 4 genes can mutations lead to cancer?
1. Proto-oncogenes
2. Tumor suppressor genes
3. Mutator genes
4. Telomerase genes


L8 - GENE & CHROMOSOME MUTATION How does a mutation in a mutator gene lead to cancer?
Mutator genes are involved in DNA repair and mutations in these genes permit higher levels of mutation in general.
L8 - GENE & CHROMOSOME MUTATION How does a mutation in a telomerase gene lead to cancer?
Leads to unlimited cell division (immortal cells).
L8 - GENE & CHROMOSOME MUTATION What is the minimum number of mutations needed for an individual to develop retinoblastoma?
2 (thus, most common in children)
L8 - GENE & CHROMOSOME MUTATION What is the minimum number of mutations needed for an individual to develop colon cancer?
4-5 (thus, most common in adults).
L8 - GENE & CHROMOSOME MUTATION What is the minimum number of mutations required for an individual to develop small-cell lung cancer?
10-15 (thus, most common in adults with high exposures to mutagens [smokers]).
L8 - GENE & CHROMOSOME MUTATION What are the 4 ways mutations can alter chromosome shape?
1. Deficiency (deletion)
2. Duplication
3. Inversion
4. Translocation


L8 - GENE & CHROMOSOME MUTATION DEFICIENCY MUTATION
DEFICIENCY MUTATION:
Loss of chromosomal segment.
L8 - GENE & CHROMOSOME MUTATION DUPLICATION MUTATION
DUPLICATION MUTATION:
Repetition of chromosomal segment.
L8 - GENE & CHROMOSOME MUTATION INVERSION MUTATION
INVERSION MUTATION:
Change in gene direction along chromosome.
L8 - GENE & CHROMOSOME MUTATION TRANSLOCATION MUTATION
TRANSLOCATION MUTATION:
Segment of one chromosome attaches to another chromosome.
L8 - GENE & CHROMOSOME MUTATION What are the 2 types of translocation mutations?
1. Simple (one-way)
2. Reciprocal (exchange)
L8 - GENE & CHROMOSOME MUTATION What are 3 ways chromosomal mutations affect gene expression?
1. Gene breaks
2. Movement to regulatory sequence
3. Movement to heterochromatic sequence

L8 - GENE & CHROMOSOME MUTATION HETEROCHROMATIC REGION
HETEROCHROMATIC REGION:
Compact, gene-poor chromosomal region.
L8 - GENE & CHROMOSOME MUTATION POSITION EFFECT
POSITION EFFECT:
When a gene's expression is altered due to movement from one region of the chromosome to another.
L8 - GENE & CHROMOSOME MUTATION TRUE/FALSE: Duplication mutations are always detrimental.
FALSE
L8 - GENE & CHROMOSOME MUTATION How can duplication mutations benefit gene evolution?
Provides an opportunity for gene evolution without loss of the original product.
L8 - GENE & CHROMOSOME MUTATION What happened to the lysozyme gene in langur monkeys?
Promoter mutations caused lysozyme gene to be expressed in the stomach instead of the tears, allowing them to digest cellulose-eating bacteria but causing more eye infections.
L8 - GENE & CHROMOSOME MUTATION What happened to the lysozyme gene in ruminants?
Duplication mutations caused the lysozyme gene to express in both the eyes and the stomach, preventing eye infections and allowing digestion of cellulose-eating bacteria.
L8 - GENE & CHROMOSOME MUTATION MONOPLOID NUMBER (X)
MONOPLOID NUMBER (X):
# of chromosome sets not including duplicated/homologous chromosomes.

Can be different from haploid number (n).


L8 - GENE & CHROMOSOME MUTATION What is an organism where the monoploid number (X) differs from the haploid number (n)?
Wheat (6X, 2n)
L8 - GENE & CHROMOSOME MUTATION What is an organism where the monoploid number (X) is identical to the haploid number (n)?
Humans (2X, 2n)
L8 - GENE & CHROMOSOME MUTATION What are the names for each monoploid number from 1X to 6X?
1X: monoploid
2X: diploid
3X: triploid
4X: tetraploid
5X: pentaploid
6X: hexaploid




L8 - GENE & CHROMOSOME MUTATION Any organism that has a monoploid number greater than 2X is what?
Polyploid
L8 - GENE & CHROMOSOME MUTATION What are 4 examples of monoploids (1X)?
1. Male bees
2. Male wasps
3. Male ants
4. Artificially derived plants


L8 - GENE & CHROMOSOME MUTATION What are the 2 types of polyploids?
1. Autopolyploids
2. Allopolyploids
L8 - GENE & CHROMOSOME MUTATION AUTOPOLYPLOID
AUTOPOLYPLOID:
Multiple chromosome sets from 1 species.
L8 - GENE & CHROMOSOME MUTATION ALLOPOLYPLOID
ALLOPOLYPLOID:
Multiple chromosome sets from different species.
L8 - GENE & CHROMOSOME MUTATION What is an example of an allopolyploid?
Triticale (wheat X rye)
L8 - GENE & CHROMOSOME MUTATION In order for an allopolyploid to form, the chromosome sets from 2 different species must be what?
Homologous
L8 - GENE & CHROMOSOME MUTATION TRIPLOID
TRIPLOID:
Result of tetraploid X diploid cross, sterile due to pairing problems during meiosis.
L8 - GENE & CHROMOSOME MUTATION What are 2 examples of triploids?
1. Bananas
2. Seedless watermelons
L8 - GENE & CHROMOSOME MUTATION What are 5 examples of polyploidy in animals?
1. Flatworms
2. Leeches
3. Brine shrimp
4. Amphibians
5. Fish



L8 - GENE & CHROMOSOME MUTATION Why are Salmonidae (salmon and trout) thought to be polyploids?
Salmonidae contain twice as much DNA as closely related fish.
L8 - GENE & CHROMOSOME MUTATION TRUE/FALSE: Polyploidy is rarer in plants than in animals.
FALSE
L8 - GENE & CHROMOSOME MUTATION ANEUPLOIDY
ANEUPLOIDY:
Chromosome number differs from wild-type by part of a chromosome set.
L8 - GENE & CHROMOSOME MUTATION MONOSOMIC
MONOSOMIC:
2n-1
L8 - GENE & CHROMOSOME MUTATION TRISOMIC
TRISOMIC:
2n+1
L8 - GENE & CHROMOSOME MUTATION NULLISOMIC
NULLISOMIC:
2n-2
L8 - GENE & CHROMOSOME MUTATION DISOMIC (haploids)
DISOMIC (haploids):
n+1
L8 - GENE & CHROMOSOME MUTATION TRUE/FALSE: Aneuploidy is generally deleterious.
TRUE
L8 - GENE & CHROMOSOME MUTATION What causes aneuploidy?
Nondisjunction during meiosis/mitosis.
L8 - GENE & CHROMOSOME MUTATION DISJUNCTION
DISJUNCTION:
Normal separation of chromosomes to opposite poles during division.
L8 - GENE & CHROMOSOME MUTATION NONDISJUNCTION (meiosis)
NONDISJUNCTION (meiosis):
Homologous chromosomes failing to separate.
L8 - GENE & CHROMOSOME MUTATION NONDISJUNCTION (mitosis)
NONDISJUNCTION (mitosis):
Sister chromatids failing to separate.
L8 - GENE & CHROMOSOME MUTATION What is an example of an aneuploidy disease in humans?
Down syndrome.
L8 - GENE & CHROMOSOME MUTATION What causes Down syndrome?
Trisomy (2n+1), extra copy of autosome #21.
L8 - GENE & CHROMOSOME MUTATION What are 4 phenotypes of Down syndrome?
1. Mental retardation
2. Broad, flat face
3. Short stature
4. Heart problems


L8 - GENE & CHROMOSOME MUTATION 1 in how many children born will have Down syndrome?
1 in 600-700 (most common human aneuploid).
L8 - GENE & CHROMOSOME MUTATION TRUE/FALSE: The chance of nondisjunction causing Down syndrome increases with the mother's age.
TRUE
L8 - GENE & CHROMOSOME MUTATION TRUE/FALSE: Most aneuploids survive to birth.
FALSE
L8 - GENE & CHROMOSOME MUTATION How many cases of Down syndrome are linked to nondisjunction in the father?
5%
L8 - GENE & CHROMOSOME MUTATION SOMATIC ANEUPLOID
SOMATIC ANEUPLOID:
Aneuploidy occurring in early development mitosis.
L8 - GENE & CHROMOSOME MUTATION GYNANDROMORPH
GYNANDROMORPH:
Genetic mosaic created by somatic aneuploidy.
L8 - GENE & CHROMOSOME MUTATION What is an example of a somatic aneuploid?
Io Moth (50% of males and 50% of females)
L9 - GENE REGULATION What are 5 potential carbon sources for bacteria?
1. Glucose
2. Lactose
3. Maltose
4. Galactose
5. Xylose



L9 - GENE REGULATION CATABOLISM
CATABOLISM:
Metabolic pathways that break down molecules into energy.
L9 - GENE REGULATION How do bacteria prevent themselves from producing the enzymes for potential carbon sources until the source is actually present?
Gene regulation.
L9 - GENE REGULATION LAC OPERON
LAC OPERON: Negative control expressed only in the presence of lactose.
L9 - GENE REGULATION Lactose serves as what for the Lac operon?
Inducer
L9 - GENE REGULATION OPERON
OPERON:
Bacterial gene that encodes several products (polycistronic).
L9 - GENE REGULATION POLYCISTRONIC
POLYCISTRONIC:
Gene that encodes several products.
L9 - GENE REGULATION What 3 products does the Lac operon encode?
1. B-galatosidase (Z)
2. Permease (Y)
3. Transacetylase (A)

L9 - GENE REGULATION What is the function of B-galatosidase (Z) in bacteria?
B-galatosidase cleaves lactose into glucose/galactose.
L9 - GENE REGULATION What is the function of permease (Y) in bacteria?
Permease transports lactose into the bacterial cell.
L9 - GENE REGULATION What is the lactose-related function of transacetylase (A) in bacteria?
Transacetylase (A) has no lactose-related function.
L9 - GENE REGULATION I GENE
I GENE: Constitutively expresses Lac repressor.
L9 - GENE REGULATION TRANS-ACTING ELEMENT
TRANS-ACTING ELEMENT:
Product of a gene that affects another gene.
L9 - GENE REGULATION CIS-ACTING ELEMENT
CIS-ACTING ELEMENT:
DNA sequence that affects adjacent genes.
L9 - GENE REGULATION OPERATOR (Lac)
OPERATOR (Lac): Portion of the Lac operon that binds to the I-gene-produced repressor.
L9 - GENE REGULATION IPTG
IPTG: Synthetic Lac operon inducer that mimics lactose structure, binding to the I-produced repressor but not cleaved.
L9 - GENE REGULATION TRUE/FALSE: IPTG concentration does not remain constant after binding to the I-produced Lac repressor.
FALSE
L9 - GENE REGULATION What happens if the operator of the Lac operon can no longer bind to the I-produced repressor?
Constitutive Lac operon expression.
L9 - GENE REGULATION Oc MUTATION
Oc MUTATION: Operator sequence changes.
L9 - GENE REGULATION I- MUTATION
I- MUTATION: Changes I-produced repressor conformation so that it no longer binds to Lac operon operator.
L9 - GENE REGULATION What happens due to I- mutation expression?
Constitutive expression of the Lac operon.
L9 - GENE REGULATION TRUE/FALSE: I- is dominant.
FALSE
L9 - GENE REGULATION Is MUTATION
Is MUTATION: Changes I-produced repressor conformation so that it no longer binds to the Lac operon inducer (lactose).
L9 - GENE REGULATION What happens due to Is mutation expression?
Lac operon is not expressed.
L9 - GENE REGULATION TRUE/FALSE: Is is dominant.
TRUE
L9 - GENE REGULATION How would you determine if the Is mutation is dominant or recessive?
Perform a cross with complementation using a partial diploid where both alleles are present in the cell.
L9 - GENE REGULATION TRUE/FALSE: It takes fewer resources for a bacteria to utilize a glucose growth medium than a lactose growth medium.
TRUE
L9 - GENE REGULATION What happens if a bacterium with a Lac operon is placed on a growth medium with both lactose and glucose?
Lac operon does not turn on; bacterium utilizes glucose.
L9 - GENE REGULATION Glucose catabolism by bacteria inhibits the formation of what?
cAMP (cyclic adenosine monophosphate).
L9 - GENE REGULATION If you increase the amount of glucose in a bacterial growth medium, the amount of cAMP produced by the bacteria does what?
cAMP production decreases.
L9 - GENE REGULATION What part of the Lac operon does cAMP bind to?
CAP (catabolite activator protein).
L9 - GENE REGULATION CAP increases the the binding of what to the Lac operon's promoter?
RNA polymerase.
L9 - GENE REGULATION TRUE/FALSE: An increase in CAP leads to an increase in Lac operon expression.
TRUE
L9 - GENE REGULATION What kind of control is the cAMP/CAP complex?
Positive (required for activation).
L9 - GENE REGULATION What are 2 gene products of a bacterium in a high glucose growth medium?
1. Inactive adenylate cyclase.
2. No cAMP.
L9 - GENE REGULATION What are 2 gene products of a bacterium in a low glucose growth medium?
1. Active adenylate cyclase.
2. cAMP.
L9 - GENE REGULATION What is the state of Lac mRNA under: glucose, no lactose?
No Lac mRNA produced.
L9 - GENE REGULATION What is the state of Lac mRNA under: glucose, lactose?
Little Lac mRNA produced.
L9 - GENE REGULATION What is the state of Lac mRNA under: no glucose, lactose?
Abunt Lac mRNA produced.
L9 - GENE REGULATION NEGATIVE CONTROL
NEGATIVE CONTROL:
Prevents expression.
L9 - GENE REGULATION POSITIVE CONTROL
POSITIVE CONTROL:
Enhances expression.
L9 - GENE REGULATION INDUCIBLE SYSTEM
INDUCIBLE SYSTEM:
Gene is normally off.
L9 - GENE REGULATION REPRESSIBLE SYSTEM
REPRESSIBLE SYSTEM:
Gene is normally on.
L9 - GENE REGULATION List examples of the 3 following components in the Lac operon: 1. Inducible system 2. Positive control 3. Negative control
1. Lac operon 2. cAMP/CAP 3. I gene
L9 - GENE REGULATION What is an example of a repressible system?
trp operon
L9 - GENE REGULATION On average, how many cis-acting elements exist in human genes?
5
L9 - GENE REGULATION What is the highest number of cis-acting elements possible in a human gene?
20
L9 - GENE REGULATION Developmental genes are regulated by what?
Regulatory cascades
L9 - GENE REGULATION MASTER SWITCH
MASTER SWITCH:
Gene that commits development down just one of many paths.
L9 - GENE REGULATION What is a developmental gene example governed by a master switch?
Sex determination
L9 - GENE REGULATION Is the Lac operon model system prokaryotic or eukaryotic?
Prokaryotic
L9 - GENE REGULATION How many RNA polymerases do eukaryotes have?
3
L9 - GENE REGULATION In eukaryotes, what RNA polymerase transcribes all mRNA?
RNA Polymerase II
L9 - GENE REGULATION To initiate transcription, what must RNA polymerase bind to?
Promoter
L9 - GENE REGULATION TRUE/FALSE: In eukaryotic gene regulation, silencers/enhancers work like volume dials, not light switches.
TRUE
L9 - GENE REGULATION ENHANCER
ENHANCER:
Enhances RNA polymerase binding.
L9 - GENE REGULATION SILENCER
SILENCER:
Inhibits RNA polymerase binding.
L9 - GENE REGULATION TRUE/FALSE: Enhancers/Silencers cannot be tissue-specific.
FALSE
L9 - GENE REGULATION TRUE/FALSE: Enhancers/Silencers can be located upstream or downstream, near to or far from the core promoter.
TRUE
L9 - GENE REGULATION CORE PROMOTER
CORE PROMOTER:
Transcription start site, where RNA polymerase binds to the DNA.
L9 - GENE REGULATION PROMOTER PROXIMAL ELEMENTS
PROMOTER PROXIMAL ELEMENTS:
1. CCAAT box
2. GC-rich region

L9 - GENE REGULATION What 3 sequences are needed to initiate transcription?
1. Core promoter
2. CCAAT box
3. GC-rich region

L9 - GENE REGULATION How far upstream from the TATA box is the core promoter?
30 BP
L9 - GENE REGULATION How far upstream from the core promoter are the promoter proximal elements?
100-200 BP
L9 - GENE REGULATION GLOBAL GENE CONTROL
GLOBAL GENE CONTROL:
Cells in one part of the body can control gene expression in other cells throughout the body (eukaryotes).
L9 - GENE REGULATION What is an example of global gene control in humans?
Endocrine system
L9 - GENE REGULATION What are 5 functions of the endocrine organs?
1. Sex determination
2. Fight/flight response
3. Metabolic rate
4. Sugar regulation
5. Growth



L9 - GENE REGULATION What kind of hormones does the endocrine system produce?
Steroid
L9 - GENE REGULATION What are the 5 steps of global gene control by the human endocrine system?
1. Endocrine cell's genes order production of enzymes
2. Cell #1's enzymes create steroid hormones
3. Steroid hormones travel through blood
4. Steroid hormones encounter receptor protein on cell #2
5. Steroid hormones bind to enhancers in cell #2's genes



L9 - GENE REGULATION A hormone-responsive enhancer represents what kind of system and what kind of control?
Inducible system, positive control.
L9 - GENE REGULATION During what 5 processes can gene products be regulated?
1. DNA transcription
2. Splicing
3. Subcellular localization
4. Subunit complex formation
5. Protein modification



L9 - GENE REGULATION What 4 protein-transitional products can be regulated?
1. Primary DNA transcript
2. mRNA
3. Polypeptide
4. Protein (inactive)


L9 - GENE REGULATION What sex is XX in fruit flies? In humans?
Both female
L9 - GENE REGULATION What sex is XY in fruit flys? In humans?
Both male
L9 - GENE REGULATION What sex is XXY in fruit flies? In humans?
Fruit flies: female
Humans: male
L9 - GENE REGULATION What sex is XO in fruit flies? In humans?
Fruit flies: male
Humans: female
L9 - GENE REGULATION Different outcomes from what 2 sex chromosomes show sex is determined by different mechanisms in fruit flies and humans?
XXY, XO
L9 - GENE REGULATION For fruit flies, an X:A ratio of 1.0 results in what sex?
Female
L9 - GENE REGULATION For fruit flies, an X:A ratio of 0.5 results in what sex?
Male
L9 - GENE REGULATION DIMER
DIMER:
Quaternary combination structure of 2 polypeptides.
L9 - GENE REGULATION In fruit flies, how many genes encode for sex-determining transcription factors?
2
L9 - GENE REGULATION In fruit flies, what does the X chromosome have that an autosomal chromosome doesn't?
Functional DNA binding domain
L9 - GENE REGULATION In fruit flies, what does the Sxl gene encode?
Female-specific splicing
L9 - GENE REGULATION In fruit flies, what does the tra gene encode?
Control of dsx gene RNA splicing.
L9 - GENE REGULATION The dsx gene in fruit flies is an example of what kind of system and what kind of control?
Repressible system, negative control?
L9 - GENE REGULATION For fruit flies, what does the dsx gene repress in females? In males?
Females: male-specific structural genes repressed.
Males: female-specific structural genes repressed.
L9 - GENE REGULATION Why does the early promoter of the Sxl gene turn on in female fruit flies, but not in males?
Many active transcription factors in females.
L9 - GENE REGULATION TRUE/FALSE: The Sxl gene in fruit flies is a master switch.
TRUE
L9 - GENE REGULATION In fruit flies, what are the 5 steps of the female-specific regulatory cascade?
1. Sxl gene ON 2. tra gene ON 3. dsx gene causes female-specific mRNA splicing 4. dsx-F protein produced 5. Male-specific genes repressed
L9 - GENE REGULATION In fruit flies, what are the 5 steps of the male-specific regulatory cascade?
1. Sxl gene OFF 2. tra gene OFF 3. dsx gene causes male-specific mRNA splicing 4. dsx-M protein produced 5. Female-specific genes repressed
L9 - GENE REGULATION In fruit flies, a null mutation of Sxl results in what sex?
Male
L9 - GENE REGULATION In fruit flies, a null mutation of tra results in what sex?
Male
L9 - GENE REGULATION TRUE/FALSE: Male is the default sex of fruit flies.
TRUE
L9 - GENE REGULATION TRUE/FALSE: Male is the default sex of humans.
FALSE
L9 - GENE REGULATION In fruit flies, a null mutation of dsx results in what sex?
Male AND female (hermaphroditic)
L9 - GENE REGULATION What determines sex in mammals?
Presence/Absence of the Y chromosome.
L9 - GENE REGULATION What are the 2 characteristics of sex determination in mammals?
1. Non-autonomous
2. Global
L9 - GENE REGULATION What are the 2 characteristics of sex determination in fruit flies?
1. Autonomous
2. Every cell
L9 - GENE REGULATION What drives the appearance of secondary sexual phenotypes in mammals?
Presence/Absence of testes.
L9 - GENE REGULATION In mammals, gonads form within how many months of conception?
2
L9 - GENE REGULATION List the 4 steps that result in the enhancement of male-specific gene expression in mammals.
1. Y chromosome present, testes form.
2. Testes secrete testosterone (steroid).
3. Testosterone binds to androgen-receptors in all body cells (global).
4. Testosterone-binding androgen receptors act as transcription factors which enhance male-specific gene expression.


L9 - GENE REGULATION What happens due to a null mutation in the androgen-receptor gene in mammals?
Tfm (testicular feminization syndrome): XY female with female secondary phenotypes but testes instead of ovaries.
L9 - GENE REGULATION TRUE/FALSE: If a woman is exposed to excess amounts of testosterone, or if she produces too much testosterone from her own body, she will become male.
FALSE
L9 - GENE REGULATION What gene drives testes formation?
SRY gene
L9 - GENE REGULATION How was the SRY gene identified?
Studies of sex reversal (XX males).
L9 - GENE REGULATION SEX REVERSAL
SEX REVERSAL:
XX males, caused by translocation of Y chromosome onto X chromosome.
L9 - GENE REGULATION What is the sex-determining master switch in mammals?
SRY gene
L9 - GENE REGULATION What gene was proved to exist when XX male mice were cloned from female mice?
SRY gene
L10 - GENETIC ENGINEERING In what year was modern biotechnology born?
1972
L10 - GENETIC ENGINEERING In what year was recombinant human insulin first produced?
1978
L10 - GENETIC ENGINEERING RECOMBINANT DNA
RECOMBINANT DNA:
DNA resulting from combinations of 2 source DNAs.
L10 - GENETIC ENGINEERING What are 5 processes that result in recombinant DNA?
1. Crossing-over during meiosis
2. Chromosomal rearrangement
3. Development of immune response cells
4. Viral/Transposon activity
5. Modern molecular techniques



L10 - GENETIC ENGINEERING CLONING
CLONING:
Creation of genetically identical copies of DNA molecules, cells, or whole organisms?
L10 - GENETIC ENGINEERING What are 3 examples of processes that result in clone creation?
1. Bacterial replication
2. Development of identical twins
3. Plant propagation from cuttings

L10 - GENETIC ENGINEERING GENETIC ENGINEERING
GENETIC ENGINEERING:
Using cloning and DNA recombination to modify a gene, cell, or organism.
L10 - GENETIC ENGINEERING What are the 4 basic tools used for the creation of recombinant DNA?
1. VECTOR (plasmids) 2. DNA CUTTERS (restriction endonucleases) 3. DNA CONNECTORS (DNA ligase) 4. DNA CLONE AMPLIFIER (E. coli)
L10 - GENETIC ENGINEERING PLASMID
PLASMID:
Circular DNA molecule.
L10 - GENETIC ENGINEERING What are the 2 types of plasmids and how many copies of each can exist in a cell?
1. STRINGENT (1-2 copies)
2. RELAXED (100s of copies)
L10 - GENETIC ENGINEERING What do bacteria use plasmids for?
Genetic exchanges
L10 - GENETIC ENGINEERING What are the 4 steps used to prepare a plasmid for use as a vector?
1. Make smaller (3 Kb) 2. Add selectable marker (ampicillin resistance) 3. Select polylinker or multiple cloning site 4. Add scorable marker (optional - LacZ gene)
L10 - GENETIC ENGINEERING What do white and blue markers indicate on a vector plasmid?
WHITE: inserted DNA
BLUE: failed to insert DNA
L10 - GENETIC ENGINEERING What do bacteria use restriction endonucleases for?
Defense against viruses.
L10 - GENETIC ENGINEERING What does the "endonuclease" in restriction endonuclease refer to?
ENDONUCLEASE: Because it cleaves DNA internally.
L10 - GENETIC ENGINEERING How does a bacterium keep restriction endonuclease from cleaving its own chromosome?
Bacterial chromosomes are methylated (marked).
L10 - GENETIC ENGINEERING What is the naming convention for restriction endonucleases?
Bacteria, strain, order of discovery Ex. HinddIII Hind: bacteria d: strain III: 3rd endonuclease discovered
L10 - GENETIC ENGINEERING What are the 4 types of RE recognition sequences?
4, 5, 6, 8
L10 - GENETIC ENGINEERING TRUE/FALSE: Larger recognition sites for REs are found more often than smaller sites.
FALSE
L10 - GENETIC ENGINEERING What are 3 examples of REs and what does each one produce after cleaving?
1. HaeIII (blunt ends) 2. HindIII (5' overhangs) 3. PstI (3' overhangs)
L10 - GENETIC ENGINEERING What do bacteria use DNA ligase for?
Connection of newly synthesized DNA fragments, DNA repair.
L10 - GENETIC ENGINEERING In genetic engineering, what is the most commonly used DNA ligase?
T4
L10 - GENETIC ENGINEERING What are the 4 steps used to join DNA fragments into recombinant molecules?
1. Cut DNA from 2 sources with same RE
2. Denature ends of each DNA and mix
3. Permit annealing of DNA ends
4. Use DNA ligase to form new phosphodiester bonds between resulting fragments


L10 - GENETIC ENGINEERING Why is DNA ligase needed to form new phosphodiester bonds between new recombinant molecules?
The new molecules are not covalently linked yet.
L10 - GENETIC ENGINEERING After recombinant molecules have been created, what 3 further steps should be followed to create an ample supply of the recombinant DNA?
1. Ligate recombinant DNA to a plasmid vector. 2. Transform E. coli bacteria by placing plasmid vector in their environment. 3. Grow E. coli to amplify recombinant DNA.
L10 - GENETIC ENGINEERING What process can create DNA clones without host cells?
Polymerase Chain Reaction (PCR).

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