Quan Exam 2 Flashcards
genetics is the study of ____; it involves the study of ___, individuals, their offspring, and the ____ within which organisms live.
heredity; cells; populations
geneticists investigate all forms of ____ and the nature of the underlying ____ of such characteristics
inherited variation; genetic basis
a ____ is constructed by mating individuals from two parent strains, each of which exhibits one of the two contrasting forms of the character under study
monohybrid cross
the physical appearance of a trait is called the ____ of the individual; the ____ properties of an organism that are genetically controlled
phenotype; observable
the specific allele or genetic constitution of an organism
genotype
individuals that result from the self fertilization of the F1 generation are called the ____
F2 generation (by an F1 cross)
mendel’s postulates
- principles of paired factors - unit factors in pairs
- Principle of dominance- dominance/recessiveness
- law of segregation (purity of gametes); mendel’s first law of inheritance
- law of independent assortment (Mendel’s second law of inheritance)
genetic characters are controlled by _____ that exist in pairs in individual organisms
unit factors
when two unlike unit factors responsible for a single character are present in a single individual, one unit factor is said to be ____ to the other, which is said to be ____
dominant; recessive
during the formation of gametes, the paired unit factors ____ or ____ randomly so that each gamete receives one or the other with equal liklihood
separate; segregate
during gamete formation, segregating pairs of unit factors ____ ____ of each other
assort independently
a diagram used to predict an outcome of a particular cross or breeding experiment
punnett square
punnett squares used by biologists to determine the probability of an offspring to have a particular ____
genotype
a ____ is constructed by mating individuals from two parent strains; there are 2 pairs of contrasting forms of character under study
dihybid cross
a sequence of DNA bases containing biologically useful information (unit factor)
gene
specific location or position of a gene on a chromosome
gene locus
alternative form of a gene (unlike unit factor)
allele
chromosome pairs of approx. the same length, centromere positioning, and staining pattern
homologues
homologues are for genes with the same corresponding gene ____
loci
the first division in meiosis separates ____
homologous chromosomes
the second division in meiosis separates _____
sister chromatids
haploid (1n) is the result of ____ and has one set of chromosomes aka gametes
meiosis
combining the gene products from the two alternative alleles produces an intermediate phenotype
incomplete or partial dominance
in a heterozygous gene, both alleles are dominant and expressed without blending
co-dominance
the existence of two or more discontinuous, segregating phenotypes in a population
polymorphism
the phenomenon of masking or modifying the effects of one gene pair by the expression of another gene pair
epistasis
expression, or the lack of expression of certain genes can affect the survival of an organism
lethal allele
the gene that determines a specific character is located on a sex chromosome; genes on sex chromosomes will NOT distribute evenly
sex linkage
during meiosis, a limited number of ____ events occur randomly between homologous chromosomes
crossover
the closer two loci reside along the axis of the chromosome, the ____ likely it is that any crossover event will occur between them
less
the ____ of a genetic disorder is the proportion of individuals with the at-risk genotype who actually express the trait
penetrance
trait is expressed in 100% of persons with that genotype
complete penetrance
an enzyme that cuts DNA at or near specific recognition nucleotide sequences known as restriction sites
restriction enzymes
in a ____ molecule, both strands terminate in a base pair
blunt-ended
____ or ____ ends are created by various overhangs (a stretch of unpaired nucleotides in the end of a DNA molecule)
adhesive; sticky
a rapid and sensitive method for radioactively, or non-isotropically, labeling DNA fragments, and is useful for visualizing small amounts of DNA
end-labeling
a type of hybridization that uses labeled complimentary DNA, RNA, or modified nucleic acid strands (i.e. probe) to localize a specific DNA or RNA sequence in a portion or section of a tissue
in situ hybridization
circular bacterial DNA
plasmid
the enzyme that has ligating ability of nucleotides
ligase
a collection of the total genomic DNA from a single organism
genomic DNA library
in a genomic DNA library, the DNA is stored in a population of identical ____, each containing a different ____ of DNA
vectors; insert
cDNA is ____ DNA that is synthesized from a ____ template in a reaction catalyzed by the enzyme _____
double-stranded; single-stranded RNA; reverse transcriptase
a method of investigating the sequence of specificity of DNA binding proteins in vitro
DNA foot printing
DNA foot printing can be used to study ____ interactions both outside and within cells
protein-DNA
a molecular biology method that is used to make specific and intentional changes to the DNA sequence of a gene and any gene products
site-directed mutagenesis
a genetic technique that uses homologous recombination to change an endogenous gene; also a replacement strategy based on homologous recombination
gene targeting
gene targeting can be used to ____ a gene, remove ____, ___ a gene, and introduce ____
delete; exons; add; point mutation
3 phases of transcription
initiation, elongation, and termination
a region of DNA that initiates transcription
promoter
the template strand of DNA has the ____ on the DNA strand
anticodons
the coding strand of DNA is the ____ that has the ____ used in translation
mRNA; codons
the sigma factor enables specific binding of ____ to ____ and is needed for ____
RNA polymerase; gene promoters; RNA synthesis
the calculated order of most frequent resides, either nucleotide or amino acid, found at each position in a sequence alignment
consensus regions in a promoter
two types of transcription termination in prokaryotes
- rho dependent
2. rho independent
rho-dependent termination is controlled by the rho protein, which tracks along behind the ____ on the growing ____ chain
polymerase; mRNA
near the end of the gene, the polymerase encounters a run of ____ on the _____ and it stalls; as a result, the rho protein collides with the polymerase; the interaction with rho releases the ____ from the ____ bubble
G nucleotides; DNA template
mRNA; transcription
rho-independent termination is controlled by specific sequences in the ____
DNA template strand
as the polymerase nears the end of the gene being transcribed, it encounters a region rich in ____ nucleotides. The mRNA folds back on itself and the complementary ____ nucleotides bind together
C-G
the result is a stable ___ that causes the polymerase to stall as soon as it begins to transcribe a region rich in ___ nucleotides; the complementary ____ region of the mRNA transcript only forms a weak interaction with the template DNA
hairpin; A-T; U-A
this, coupled with the stalled polymerase, induces enough instability for the ____ to break away and liberate the new ____
core enzyme; mRNA transcript
mRNA transcription that has genetic information in it that will create many proteins
polycistronic transcription
mRNA transcription that contains only the genetic information for 1 protein
monocistronic transcription
what does an operon consist of?
three adjacent structural genes, a promoter, a terminator, and an operator
a substance that acts on an operon to inhibit mRNA synthesis
repressor
a segment of DNA to which a transcription factor binds to regulate gene expression
operator
the lac operon is regulated by several factors including the availability of ____ and ____
glucose; lactose
lac operon can be activated by _____
allolactose
lactose binds to the ____ of lac operon and prevents it from repressing ____
repressor protein; gene transcription
components of chromatin
protein, RNA, and DNA
the most tightly packed DNA, it is transcriptionally silent, and differs from cell to cell
heterochromatin
de-condensed DNA that is transcriptionally active
euchromatin
____ is chromatin that is decondensed and can be ____; ____ is condensed and cannot be ____
euchromatin is decondensed and can be transcribed
heterochromatin is condensed and cannot be transcribed
which polymerase transcribes mRNA?
polymerase 2
there are ___ general transcription factors that bind to all genes and there are _____ that will only bind to certain genes
5; gene-specific transcription factors
_____ are needed to bind pol 2 to the promoter
general transcription factors
_____ is the first transcription factor to bind to DNA
TBP (transcription binding protein)
location of enhancers
upstream, downstream, or in reverse orientation (last one is not natural and must be engineered)
____ limit the distance that enhancers operate; these proteins ___ the gene from outside effects
insulators; buffer
insulators prevent the ___ region from acting outside the ____ and prevent the spread of _____
control; domain; heterochromatin
an independently folded protein domain that contains at least one structural motif that recognizes double- or single-stranded DNA
DNA binding domain
DNA binding domains include ____ and _____
zinc finger proteins; leucine-zipper proteins
3 types of RNA processing
- 5’ capping
- addition of the poly A tail (3’ polyadenylation)
- splicing of introns (RNA splicing)
polyadenylation involves lots of ____ added at the ___ end
adenosines; 3’
splicing of an RNA molecule:
- cleavage at the 5’ splice site
- formation of a lariat like intermediate
- cleavage at the 3’ splice site
- exons are ligated
how cells communicate with eachother
intercellular signaling
signaling within a cell
intracellular signaling
an extracellular signaling molecule binds to a ____ which activates ____ that can interact with ____
receptor protein; intracellular signaling proteins; target proteins
target proteins can have an effect on ____, alter ____, and alter ____ or _____
cell metabolism; gene expression; cell shape; movement
location of receptors
cell surface receptors and intracellular receptors
different types of intercellular signaling
contact dependent, paracrine, synaptic, and endocrine
can one signaling molecule perform multiple functions?
yes
signaling through cascade of intermediate signaling complexes happens through a series of ____ reactions which are initiated by a ____ or ____ acting on a receptor
chemical; stimulus; first messenger
signaling is transduced to the cell interior through ____ (which ____ the initial signal) and ultimately to _____, resulting in a cell response to the initial stimulus
second messengers; amplify; effector molecules
_____ and ____ have extracellular ligand binding domains and cytoplasmic catalytic domains
intrinsic tyrosine kinase receptors; intrinsic serine kinase receptors
ion channel-linked receptors; there are 5
ionotropic receptors
____ are very important in muscle contraction
nicotinic acetylcholine receptors (nAChRs)
2 types of metabotropic receptors
muscarinic acetylcholine receptors and beta-adrenergic receptors
receptor inactivation
- receptor sequestration
- receptor down regulation
- receptor inactivation
- production of inhibitory protein
types of G protein coupled receptors:
Alpha S, Alpha I, and Alpha Q
alpha S stimulates ____
adenylyl cyclase
Alpha I inhibits ____
adenylyl cyclase
Alpha Q activates ____
phospholipase C (PLC)
in dissociation of G protein subunits, the ____ will deactivate from the ____when activated/phosphorylated and can then interact with whatever next molecule in a sequence
alpha unit; beta gamma unit
____ dissociates when activated by ____, a small molecule that plays a key role in the regulation of intracellular signal transduction
protein kinase A; cAMP
cAMP is derived from ____ by the catalytic action of a signaling enzyme ____
ATP; adenylyl cyclase
protein kinase A phosphorylates something and ____ removes a phosphate
protein phosphatase-1
cAMP transduces its effects on ____ interconversion by regulating a key signaling enzyme, _____
glycogen-glucose-1-phosphate; protein kinase A (PKA)
PKA phosphorylates target proteins on ____ and ____ residues
serine; threonine
a calcium channel that stimulates intracellular calcium mobilization
IP3
activates protein kinase C
DAG
____ is an activating cofactor for PKC; in the absence of ___, PKC activity will be repressed
Ca++
enzyme-linked receptors:
- insulin
- insulin-like growth factors (IGFs)
- nerve growth factor (NGF)
- brain derived neurotrophic factor (BDNF)
- epidermal growth factor (EGF)
- platelet derived growth factor (PDGF)
enzyme-linked receptors do not use ____ and are specifically used in ____
G-proteins; cell growth
receptor dimerization: in _____, a signal molecule will interact and cause _____
receptor tyrosine kinase (RTK); autophosphorylation
in receptor dimerization, the two domains in the ____ will come together, inducing ____ of the other domain
receptor tyrosine kinase (RTK); phosphorylation (autophosphorylation)
Ras are small ____ involved in ____
G-proteins; cell proliferation
Ras are ____, they have ___ dependent switches, and they activate ____
membrane bound; GTP; MAP kinases
the phosphorylation cascade results in a change in ____ or ____
gene expression; protein activity
____ use the NF-kB signaling pathway; this pathway starts with a ____ and eventually NF-kB translocates to the ____
cytokines; TNF-alpha (tumor necrosis factor); nucleus
in the nucleus, NF-kB binds with a ____, then the cell can transcribe _____
coactivator; target NF-kB genes
start codon
AUG / methionine; signals the start of protein synthesis
this will be dictated by the start codon, and each successive triplet will be read in register until a stop codon is reached
reading frame
transfer RNA is a ____ shaped structure with the codon on the “middle leaf” that will signal a ____
cloverleaf; amino acid
amino-acyl tRNA is an enzyme that catalyzes the formation of an ____ bond, linking the ____ of the adenosine nucleotide of the tRNA to the ____ group of the amino acid (A site inside the ribosome)
ester; 3’ hydroxyl group; carboxyl
stop codons
UAA, UAG, UGA
signal the end of protein synthesis and do not specify an amino acid
____ are used to facilitate protein folding
molecular chaperones
cellular machinery for protein turnover; a multicatalytic complex designed for degradation of cytosolic proteins
proteasome
targets proteins to the proteasome for degradation
ubiquitin
