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Cell Biology
Test 1 Clark (UNR)
105
Biology
Undergraduate 3
02/04/2011

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Term
What is Cell Biology?
Definition
the study of structure, function,
behavior & evolution of cells at a molecular level
Term
What is a cell?
Definition
the structural & functional unit of life
Term
What do all cells use to transcribe info?
Definition
RNA
Term
what reads each codon & converts information
to a specific amino acid
Definition
tRNA
Term
what do all cells use as catalysts?
Definition
protiens
Term
what is free energy used for?
Definition
to create bioogical order among living cells
Term
main source of energy for living orgsanisms?
Definition
sun
Term
what are the macromolecules of sugars, amino acids, and nucleotides?
Definition
polysacharides
protiens
nucleic acids
Term
all cells are at least enclosed by what?
Definition
plasma membrane
Term
two domains of prokaryotes?
Definition
bacteria archaea
Term
algae, protozoans, and fungi are all what?
Definition
Eukaryotes
Term
What to plant cells have in comparison to animal cells?
Definition
cell wall, chloroplasts & large
vacuoles
Term
abiogenesis
Definition
origin of life from non living matter (primordial soup theory)
Term
What is RNA world hypothesis?
Definition
Short RNAs catalyze & are templates for their own replication were precursors to living organisms.
Term
What did the first cell likely look like?
Definition
Replicating RNA in a phospholipid bilayer
Term
How did metabolism evolve
Definition
glycolysis, photosynthesis, oxidative metabolism
Term
What things make a cell easy to study?
Definition
Small
Easy to grow/raise/isolate
Fast generation time
‘Workable’ genetics
Good imaging, e.g. transparent
Cheap
Term
What organisms are best for scientific study?
Definition
tobacco mossaic virus, e. coli, sacromyoces yeast, C. elegans, drosophilia & mice, zebra fish, frogs, thaliana (plant)
Term
the ability to distinguish objects in small distances appart
Definition
resolution
Term
Describe brightfield microscopy
Definition
Cell structures seen by labeling proteins & nucleic acids w/ stains & dyes. Fixation
Term
what microscopy is ideal for living organisms?
Definition
DIC, or phase contrast. (clear)
Term
describe epiflouresent microscopy
Definition
flouresent probes label proteins, (live cells)
Term
describe confocal microscopy
Definition
Enhances contrast & detail by
removing out of focus light
Term
what microscopy can detect subcellular & macromolecular structures?
Definition
SEM & TEM
Term
whats the difference between velocity and equilibrium sedimentation
Definition
seperation based on size and shape, vs. based on buoyant density
Term
how does ion exchange chromatography work?
Definition
cells are separated based on charge
Term
how goes gel filtration chromatography work?
Definition
separates ions based on size
Term
how does affinity chromatography work?
Definition
separates ions based on their affinity to other substrates
Term
Key Characteristics of Prokaryotes?
Definition
usually single celled, no nucleus, cell walls, small
Term
what is a molecule?
Definition
a groups of atoms held together by a covalent bond
Term
what is an ionic bond
Definition
when electrons are donated from one atom to another.
Term
what polarity are covalent bonds?
Definition
either
Term
what are electrostatic attractions?
Definition
attractions between oppositely charged particles
Term
What is a hydrogen bond?
Definition
electropositive hydrogen attracted to electronegative. (stronger in sraight line)
Term
What are van der waals attractons?
Definition
change in the electron cloud of a nonpolar atom induces an oppositely polarized dipole in a nearby nonpolar atom.
Term
what effect draws together non polar molecules in aqueous solution?
Definition
the hydrophobic affect (like oil coming together on top of water
Term
what are the simplest lipids?
Definition
fatty acids
Term
define amphipathic
Definition
part water soluble & part insoluble
Term
amino acids link with what bond to become what?
Definition
peptide bonds
polypeptides
Term
nucleotides use what bonds to form what?
Definition
phosphodiester bonds
nucleic acids
Term
Two strands of DNA are held together by?
Definition
hydrogen bonds and stacking interacitons
Term
What are the functions of nulceotides?
Definition
1. subunits of DNA & RNA
2. Chemical energy (ATP)
Term
How do cells not break the 2nd law of thermodynamics?
Definition
release heat
coupled reactions
Term
3 examples of potential energy
Definition
chemical bond
concentration gradients
electric potential
Term
4 examples of kintetic energy
Definition
heat
electromagnetic
mechanical
electric
Term
photosysnthesis converts _______ energy to __________ energy
Definition
electromagnetic energy
potential
Term
are ALL chemical rxns reversible?
Definition
yes!
Term
2 functions of catalysts
Definition
lower activation energy w/o being consumed
DOESN't alter chemical products and reactants at equilibrium
Term
energetically favorable rxns
reduce_____
increase_________
Definition
free energy
disorder
Term
what is delta G at equilibrium
in an Exergonic Rxn Delta G =?
In an endergonic Rxn Delta G =?
Definition
G=0
G<1
G>1
Term
condensation rxns are energetically______
4 examples of condensation rxns?
Definition
unfavorable
ATP hydrolysis,
polysacharide, nucleic acid & protein formation
Term
What amino acids are acidic?
What's unique about them?
Definition
Glu & Asp
Hydrophilic, found on outside of proteins.
Term
What amino acids are basic?
Definition
Argenine, Lysine & Histodine
Term
What amino acids are polar & uncharged?
what's unique about them?
Definition
Asparagine, Glutamine, Serine, Threonine, & Tyrosine
hydrophilic, form H bonds, outside proteins
Term
Acids are Proton ______
Definition
Donors
Term
What kind of bonds influence protein folding?
Definition
non covalent bonds
Term
What do chaperones do?
Definition
facilitate proper folding of proteins
Term
What do disulfide bonds do?
where usually found?
Definition
stablize protein structure
lysosomal &
secretory proteins
Term
What is mad cow disease caused by?
Definition
misfolded protein (prion) which causes formation of protein aggregates.
Term
3 general protein structures?
Definition
globular, fiberous, integral membrane
Term
Where might an alpha helix protein be found?
Definition
in a transmembrane area
Term
What stabolizes the backbone in a Beta sheet?
Definition
H bonds
Term
What is tertiary structure defined by?
Definition
interacitions between side chains of amino acids
noncovalent bonds & hydrophobic interactions
Term
Quatranary struture is a complex of?
ex?
Definition
multiple proteins
hemoglobin
Term
What is a domain
Definition
a region that can fold independantly into a compact stable structure.
Term
about how many protein domains are there?
common potein domains are called?
Definition
2K
protein modules
Term
Homologs:
Definition
proteins or genes that share a common ancestor
Term
Arangement of domains is usually lost or conserved?
Definition
conserved
Term
What kidn of activities do proteins regulate?
Definition
structure,regulation, movement, catalyst, signaling & transport
Term
How do Ligands Bind proteins?
Definition
non covalent bonds
Term
Specivity?
Affinity?
Definition
Specificity: ability of a protein to bind one molecule over others.
Affinity: tightness or strength of binding.
Term
What are the two models of enzyme/substrate interactions?
Definition
lock and key model
induced fit (glove)
Term
How do enzymes promote catalysis
Definition
binds two substrates & makes them change
binds substrate to enzyme to create partial - or + rxn
strains bound substrate &forces change
Term
How is protein synthesis and degredation regulated?
Definition
1. rate of mRNA transcription
2. mRNA processing, export &
stability
3. rate of translation
4. rate of degradation
Term
What determines the lifespan of a protein?
Definition
Susceptibility to proteolytic degradation (eliminates misfolded or damages proteins)
Term
what molecule degrades proteins?
Definition
ubiquitin & lysosomes
Term
what is allosteric regulation
Definition
the end product goes to the beginning of the chain & inhibits the chain.
Term
Allostery:
Definition
any change in a protein’s
tertiary or quaternary structure induced by noncovalent binding of a
regulatory molecule (allosteric effector).
Term
what does phosphorylation do to protein activity?
Definition
activates or inhibits it
Term
what is atomic weight?
Atomic Number?
Definition
Atomic Weight = No. of Protons + No. of Neutrons
Atomic Number = No. of Protons
Term
4 types of macromolecules in a cell?
Definition
carbs, lipids, proteins, & nucleic acids
Term
glycogen is in _______cells
and Starch is in _______cells
Definition
animal
plant
Term
Difference between a nucleotide and a nucleoside
Definition
nucleoside = sugar +base
nucleotide = sugar + base + phosphate
Term
what is a karyotype?
Definition
display of chromosomes at mitosis
Term
Chromosome:
Chromatin:
Definition
chromosome: single, linear DNA molecule with associated proteins that pack DNA into a more compact structure
chromatin: complex of DNA & protein
Term
pseudogene
Definition
pseudogene: duplicated gene inactivated by mutation
Term
what is essential for chromosome duplication?
Definition
Centromere, replication origins & two
telomeres
Term
what is the structural unit of
chromatin
what do they contain?
Definition
nucleosome

DNA & histones
Term
what are nucleosomes made of?
Definition
mostly basic amino acids
Term
what does H1 histone do?
Definition
helps pull nucleosomes into
30 nm fiber
Term
what phase of chromosomes contain regions of
euchromatin & heterochromatin?
Definition
Interphase
Term
Euchromatin:

Heterochromatin:
Definition
euchromatin: ‘transcriptionally active’, open, decondensed
heterochromatin: ‘transcriptionally inactive’, closed, condensed
Term
How does DNA become accessible?
Definition
Chromatin-remodeling complexes use energy from
ATP hydrolysis to move nucleosomes &
decondense chromatin.
Term
At what step can gene expression be regulated?
Definition
transcription
RNA processing
RNA transport
mRNA degredation
translation
protein activity
Term
What is the most important regulatory mechanism in genes?
Definition
initiating transcription
Term
What makes RNA from a DNA template?
Definition
RNA polymerase
Term
3 steps of transcription in bacteria?
Definition
initiation
elongation
termination
Term
What do repressors do?
activators?
Definition
turn genes off
on
Term
Two parts of transcriptions activators?
Definition
DNA binding domain + activation domain
Term
Wht is passive repression?
Definition
Repressors can compete with activator for same DNA binding site
Term
Where is the control region in most eukaryotic genes?
Definition
Control region includes promoter (where Pol II & general transcription
factors assemble) & regulatory sequences.
Term
What does a DNA binding Domain do?
Activation Domain?
Definition
Recognizes a specificity DNA sequence
Term
How can inhibitors inhibit transcription?
Definition
interacting with Mediator,
general transcription factors or
corepressors
Term
What do HATs Do?
What to HDACs Do?
Definition
activate transcription by adding acetyl groups
repress it by removing them
Term
does DNA methylation turn genes off or on?
Definition
off
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