Midterm 1 Flashcards
What is modern cell theory
al living things are made up of one or more cells, all cells arise from pre existing cells by division
What features do all cells share?
- contain DNA
- plasma membranes
- enzymes
- ATP
small molecules only have _ - forms of amino acids and _- forms of sugars
L + D
WHt are some characteristics of prokaryotes
- no internal membrane components
- no organelles like mitochondria and vaccuoles
- transcription and translation coupled
What are some characteristics of eukaryotes
- internal membrane components
- eukaryote is a monophyletic group
- membrane bound organelles
What separates transcription and translation
the nuclear membrane
What is the nuclear envelope
small molecules and ions can passively diffuse though, however large proteins and RNA require active transport
What is endocytosis
regions of the plasma membrane containing transmembrane protein receptors are invaginated by cytoplasmic coating which pinches off a coated vesicle.
What is phagocytosis
Large insoluble extracellular material taken into a phagosome and delivered to lysosome from destruction
what is autophagy
intracellular material and damaged organelles are engulfed by ER membrane
what is the difference between mono and polycistronic mRNA
monocistronic mRNA is used by eukaryotes and only can translate a single protein at a time
polycistronic mRNA is used by prokaryotes and can translate more than one protein at a time
T or F- Nuclear export can occur in both eukaryotes and prokaryotes
F- only in eukaryotes
T or F- Prokaryotes and Eukaryotes have different ribosome structures
T, 30S+50S prokaryotes + 40S+60S eukaryotes
Are proteins held together by covalent or ionic bonds
covalent
are lipids held together by covalent or ionic bonds
ionic
What are the 4 protein hierarchies + brief descriptions
Primary structure
Secondary structure- a helix and B pleated sheets
Tertiary structure- Folded into 3D conformation
Quaternary structure- multimeric conformation
What are the roles of quaternary proteins
regulation, signalling, transport, catalysis and movement
what is the difference between nucleotides and nucleosides
nucleosides lack a phosphate
phospholipids contain a ________ head and _________ tails
hydrophillic head + hydrophobic tails
what is the endosymbiotic theory
mitochondria and chloroplasts were once primitive bacterial cells
T or F- mitochondria and chloroplasts replicate separately from nuclear DNA
T
what kind of DNA reveals ancient human migration patterns
mtDNA
how is malaria trated
choloroquine and quinine interfere with merozoites ability to degrade hemoglobin, needed for parasite protein synthesis and energy
what are antibiotics
small molecules that ill or inhibit growth or microorganisms
what are useful features for a model organsims
small, easy feeding, non dangerous, short generation time, readily available
what is a common model organsim
yeast, many benefits of both bacteria and eukaryotic cells
what are temperature sensitive mutations
organism only able to grow at permissive tempature, unfolds at nonpermissive temperature
what are the four types of animal tissues
connective, epithelial, muscle and nervous
what is a plants delivery system
the xylem and phloem
how are plant cells held together
plasmodesmata
how are animal cells held together
CAMs (cell adhesion molecules), made of collagen
the cells of epithelium are _______.
polarized
blood vessels are lined with _______ to prevent leakage
endothelium
only about __ % of human DNA encodes proteins
10%
how do we study gene regulation?
observing the pattern of expression through delevopmental time
how are C. elegans a model organsim
-smal, short generation time (3 days) , hermaphroditic, transparent, easy to culture and maintain
T or F- worms can model human disease
T, disease model for alzheimers, parkinsons, etc
T or F: the order in humans and in mice is conserved
T, we share around 99% of genes with mice
what is synteny
occurence of genes in the same order on a chromosome in 2 or more difference species
why do humans appear so different from apes?
different regulation of genes
what are many genetic diseases casued by
mutations
what are the three steps for isolating organelles
- lyse the cells
- seaparate organelles
- use for further study
what are three techniques that can be used to disrupt the cell membrane
High speed blending
Sonication
Tissue homoginizer
what is simple diffusion
can move freely across a concentration gradient
what is facillitated diffusion
channels against a concentration gradiet
after lysis, the mix of suspended cellular components is called the _______
homogenate
What is sequential differential centrifugation
yeilds fractions of organelles that differ in mass and density
what is equilibrium density-gradient centrifugation
separates cellular components by density, more specific
how can cell components be identified after centrifugation
using organelle specific antibodies
or proteomic analysis to identify the protein components
How do organelle specific antibodies work
binding of the antibody provides and handle that helps identify and pruify the organelle
what are the three steps in proteomic analysis of organelles
- isolation of organelle at high purity
- digest with protease, determine pass and sequence using spectrometry
- genome sequence for reference comparison
what does a hermatocrit do
it is the volume of blood cells that are packed by centrifugation, can detect anemia
what is the fluorescence activated cell sorter (FACS)
analyzes and selects cells from thousands of others and sorts them into a separate culture dish
what are monoclonal antibodies
antibodies that are made by identical immune cells that are all clones of a unique parent cell. They all bind to the same epitope
what is the definition of a drug
non-food compounds that cause physiological changes, by binding to targets
what dictates the outcome of a drug
the interaction between the drug and its target
WHat are the two types of strategies when it comes to drug development
Phenoytpe based approach
Target based approach
What is a phenotype based approach
start with asssays, add potential drugs and look for desirable change, then identifiy hits and targets
what is a target based approach
start with a target selected from a biochemical pathway that is linked to a specific disease state, produce enough to convert hits to leads
in light microscopy, resolution is limited by ____ _________
light wavelength
What is the coefficient for resolution and what does it mean?
D, the minimum distance between two distinguishable objects, smaller D value, the better the resolution
What is phase contrast microscopy
degree of darkness depends on the refractive index
what is differential interference contrast microscopy
thin optical section of the objects, detail in thicker objects
what are the three steps in preparing tissues for light microscopy
- Fixing- chemical cross linking of proteins
- Sectioning- cutting tissue into thin slices
- Staining
What is an H+E stain
a stain in which hematoxylin binds to basic molecules wile eosin binds to acidic molecules
what is fluroescence microscopy
absorbs light at one wavelength and requires a dichroic mirror, uses stains
what is immunoflourescence microscopy
commonly used to detect the location of specific proteins, indirect because the flurorochrome is on the secondary antiobdy
what are some advantages to immunoflurescence microscopy
images for different wavelenghts, electronically merged images, secondary antibodes are cheaper
how else can antibodies be targeted to a protein of interest
make a recombiant protein that contains an epitope tag
what are two drawbacks to fluorescence microscopy
cant visualize thick specimens, blurring the image outside the plane of focus
what is confocal microscopy
collect many images and build up the final figure electronically, collect light from small areas at a time
what are the two different types of advance fluorescence microscopy technieques
FRAP (fluoresence recovery after photobleaching) and FRET (forster resonance energy transfer)
What is FRAP
uses high intensity light to pleach transmembrane protein until it no longer fluresces
what is FRET
measures the distance between fluorochromes, reveals protein interactions
What is electron microscopy and the 2 main types
short wavelength yields high resolution images, TEM and SEM
What is Transmission electron microscopy
image is derived from electrons that have passed through the specimen
what is scanning electron microscopy (SEM)
metal-shadowed material reveals the surface features
phospholipids are ampipathic– what does this mean?
have both hydrophillic and hydrophobic properties
T or F: heat can affect the fluidity of a membrane
T!
with a small polar head, what shape does the layer form?
favour inverted micelles
with a similar polar head and hydrophoic regions what does the layer form?
pefers bilayers
with a bulky polar head and only one acyl chain, what does the layer form?
pefers micelles
What are the three types of phospholipids
phosphoglycerides, sphingolipids, and sterols
What are sphingolipids
class of compounds that are fatty acid derivatives of sphingosine
what are sterols
single polar hydroxyl with conjugated 4 ring hydrocarbon tail
where are phospholipids synthesized
cytosolic face of ER
where is sphingomylein synthesized
exoplasmic face of Golgi complex
what helps maintain fluidity in the lipid bilayer
cholesterol
are lysolipids more on the inner or outer leaflet
outer leaflet
where are excess lipids soterd
ER membrane
What are the 3 types of biological membranes
intergral, lipid anchored and periphrial proteins
What are some characteristics of intergral proteins
maily hydrophobic, 20-25 amino acids, positively charged with Arg _ Lys anchor
what are annular phospholipids
fatty acyl chains pack tightly against irregular hydrophobic outer face to form shell around the protein
what are transmembrane helices
guide assembly and stabilization of the bilayer core
what are lipid anchored proteins
protein bound covalently to one or more lipid molecules, lipid protein inserted to one leaflet of the membane
T or F: membrane proteins can flip flop across the membane
F
what are preiphrial membrane proteins
do not directly contact the hydrophobic core, invocled with associating cytoskeleton with plasma membrane
what do lipid binding motifs do
target periphrial proteins to the membane
What do detergents do
can be sued to solubilize lipids and membrane proteins
T or F: detergents are ampipathic
T
what is the difference between ionic and nonionic detergents
ionic deterents contain a charged group while nonionic detergents lack one
what do ionic detergents do
tend to denature proteins
what do nonionic detergents do
can extract transmembrane proteins in folded (Active) form
T or F: Detergents cannot form micelles
F, at high concentrations
What is the soluble portion of the chloroplast
the stroma
where does light energy capture occur in chloroplasts
thykaloid membrane
photosynthesis consists of both ____ and ____ reactions
light and dark
where do dark reactions occur
in the stroma
what happens in the dark reaction
uses NADPH and ATP to drive the endergonic process of sugar formation (hexose)
what are the 4 stages of photosynthesis
- light absorption and O2 formation from H2O
- Electron transport binding to reduce NADP + to NADPH and PMF generation
- Synthesis of ATP
- Carbon fixation, conversion of CO2 to carbohydrates
what does DCPIP do
it can replace the final electron acceptor in photosynthesis
how do cells synthesize new membranes
by the expansion of existing membranes
what is fatty acid biosynthesis needed for
phospholipids and sphingolipids
Saturated fatty acids have __ double bonds
no
what does fatty acid synthease do
generates saturated fatty acids from ocndensation of malonyl coA and acetyl CoA
what do cytosolic proteins do
transport fatty acids in the cytosol
What are the four types of lipoproteins in the bloodstream
Chylomicrons- transport triglycerides
VLDL (Very low density lipoproteins) synthesize and release by lliver, cells remove triglycerides becoming LDL
LDL- less healthy, deliver cholesterol to tissues
HDL- healthy, return excess cholesterol from tissues and bring back to liver
What are lipid bilayers impermeable to
ions, amino acids, water, sugars
T or F- without lipid bilayer, life would not be possible
T
simple diffusion rate is proportion to its _____ _______
concentration gradient
how do we measure simple diffusion
partition coefficeint, K. the higher the K the faster to cross a bilayer
What are the 3 types of transport proteins
Channels, transporters and ATP powered pumps
What do channels do
Form protein lined pathway though the membrane, allows hydrophillic molecules to avoid interacting with the interior
What do transporters do
selective, unipoerters, symporters and anitporters transport molecules up or down a concentration gradient
what do ATP-powered pumps do
use energy of ATP hydrolysis to transport up a chemical concentration gradient, primary active transport
Is the Na/K pup primary or secondary active transport
primary
Na/lysine symporter primary or secondary
secondary
K+ channel releases K+ ___ (up or down) gradient
down
Glucose is used as a substrate for ___
ATP
what is Vmax
the maximum transport rate
what does GLUT1 do
a uniporter of glucose
what happens to glucose inside the cell
enters glycolysis. phosphorylation rapid and constant
aquaporins increase water _____ of cellular membranes
permebillity
