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133 Cards in this Set

  • Front
  • Back
What is the size of a virus?
20-300 nm
Why is a virus not considered alive?
Viruses are not able to self replicate, they must rely on the machinery of a host. Viruses also cannot perform metabolism.
What is the size of mycoplasma?
100 nm
How large is an average bacteria?
How long is the cell cycle of an average bacteria?
20 minutes
What are some differences between bacteria and eukaryotic cells?
Bacterial contain no membrane bound organelles. The structure of DNA is different. Bacteria undergo binary fission. Bacteria do not process RNA after is it created.
What are some similarities between bacteria and eukaryotic cells?
The function of ribosome is the same (structure is similar). DNA replication, lipid bilayer, aerobic cellular respiration.
Where do ribosomes in the rough ER excrete their proteins?
They are excreted into the lumer of the ER.
What are the three forms of light microscopy?
Conventional wide field, video microscopy, and laser scanning confocal microscopy.
What are the two types of Electron Microscopy?
Trasmission and Scanning
What is the typical wavelenght of the various forms of ligh microscopy?
500 nm
What is the resolution of the various forms of light microscopy?
200 nm
What is the wavelenght of the beam used in Electron Microscopy?
0.01 nm
What is the resolution of TEM?
1-2 nm
What is the resolution of SEM?
10-20 nm
What is the resolution of X-Ray Crystallography?
0.1 nm
What is the wavelenght of the X-Rays used in X-Ray Crystallography?
0.15 nm
What is the resolution of a microscope limited by?
The wavelenght of the light used.
What are the different types of light interference used in light microscopy?
dark-field, phase contrast, and differential interference contrast
What are three benefits of indirect immunofluorescence?
specificity, selectivity, and sensitivity
In relation to the excitation wavelength, what wavelenght is emitted by a sample?
The emission wavelenght is always longer than the excitation wavelength. (Lower energy is always emitted).
What is the color used to excite DAPI?
What is the color used to excite Fluorescein?
What is the color used to excite Rhodamine?
What is the color used to excite GFP?
What color is emitted by DAPI?
What color is emitted by Fluorescein?
What color is emitted by Rhodamine?
What color is emitted by GFP?
What is the only molecule that DAPI will bind to, and where is it found?
DAPI will only bind to DNA in the nucleus or mitochondria.
How are samples prepared for TEM?
The specimen is first fixed using glutaraldehyde and osmium tetroxide. It is them dehydrated and embedded in expoy resin. Sections 50-100 nm thick are cut and layed on a copper grid for support. The sample is then stained with a heavy metal.
What method of microscopy gives 3-D images of the surface of the sample?
What does glutaraldehyde do in the fixation of samples for TEM?
cross-links proteins
What does osmium tetroxide do in the fixation of samples for TEM?
cross-links lipids
What is the name used to describe the vibration of molecules?
Brownian Motion
When are ionic bonds the strogest?
In the absence of water.
What is the general form of amino acids?
A central carbon surrounded by an amino group (NH2), a carboxyl group (COOH), a hydrogen atom, and a side-chain group.
Which of the substiuent groups of an amino acid dictates it's function?
The "R" group.
What is release when a peptide bond is formed?
What are the basic amino acids?
lysine, arginine, histine
What are the acidic amino acids?
aspartic acid and glutamic acid
What amino acids are polar and which atom in the side group causes this?
asparagine (N), glutamine (N), serine (-OH), threonine (-OH), and tyrosine (-OH)
What amino acids can be phosphorylated?
serine, threonine, and tyrosine
Between which amino acids can a disulfide bond be formed?
Between two cysteine amino acids.
How are amino acids phosphorylated?
Which enzyme dephosphorylates amino acids?
What are the two common shapes of protein domains?
α-helix and β-sheet
What is the primary structure of amino acids?
The sequence of amino acids.
What is the secondary structure of amino acids?
The α-helices and β-sheets.
What is the tertiary structure of amino acids?
Three dimensional structure of single poly peptide chain.
What is the quartenary structure of amino acids?
A complex made up of several poly peptide chains.
What does "amphipathic" mean?
A amphipathic molecule has both polar and non-polar regions (phospholipids)
What is the general form of phospholipids?
A polar head made of choline, phosphate, and glycerol bound to 2 non-polar hydrocardon tails.
If phospholipids are placed in water, what form will they take?
They will spontaneously form into a spherical bilayer (micelle) that isolates the non-polar tails toward the inside of the bilayer and the polar heads to water surrounding the micelle.
In what direction do phospholipids more rapidly?
Laterally within the leaflet.
What determines the fluidity of the bilayer?
The temperature of the environment and the composition of the tail.
Where are glycolipids found in cells?
They are always bound to the extracellular side of the plasma membrane.
How are proteins in the PM visualized?
freeze fracture
What are the four classes of membrane proteins?
transporters, anchors, receptors, and enzymes
Where are membrane proteins found in the PM?
Proteins can either be integral and are anchored directly to the PM or peripheral and attached to an integral protein in the PM.
What protein structure is commonly found within the PM?
What membrane proteins are almost always glycosylated?
Transmembrane proteins
How can membrane proteins be removed from the PM?
Membrane proteins can be solubilized by detergents such as SDS (sodium dodecyl sulfate) or Triton X-100.
What detergent will not denature proteins?
Triton X-100
Which detergent will denature proteins?
SDS (sodium dodecyl sulfate)
How can membrane proteins on the cytoplasmic side be studied?
By lysing Red Blood Cells and turning them inside out.
What procedure can be used to identify PM proteins ?
SDS-gel electrophoresis
What are the major proteins of RBCs?
α spectrin, β spectrin, ankyrin, band 3, glycophorin, band 4.1, and actin
What is the function of spectrin, ankyrin, and actin?
They form a membrane that gives the PM mechanical strenght. This is called the cytoskeleton.
What proteins make up the cytoskeleton?
spectrin, ankyrin, and actin
What is the function of ankyrin?
Ankyrin attaches spectrin to band 3
What is the funciton of band 4.1?
Band 4.1 binds glycophorin to a spectrin-actin complex.
Which of the major PM proteins is an ion channel?
Band 3
Describe the Frye and Edidin experiment.
Two cells' membrane proteins were labeled with different fluorphores. The two cells were then fused. The diffusion of the proteins could be monitored based on their different fluorescence.
What RBC plasma membranes proteins are integral?
Band 3 and glycophorin
What RBC plasma membranes proteins are peripheral?
Spectrin, actin, ankyrin, and band 4.1
What RBC plasma membranes proteins are transmembrane?
Band 3 and glycophorin
What RBC plasma membranes proteins are glycosylated?
Band 3 and glycophorin
Where are RBC plasma membrane proteins glycosylated?
The extracellular side of the plasma membrane
What is the intracellular concentration of NaCl in a RBC?
.15 mM
What is the concentration of Na+ within the cell and outside of the cell?
5-15 mM inside and 145 mM outside
What is the concentration of K+ within the cell and outside of the cell?
140 mM inside and 5 mM outside
What is the concentration of Mg2+ within the cell and outside of the cell?
0.5 mM inside and 1-2 mM
What is the concentration of Ca2+ within the cell and outside of the cell?
What is the pH within the cell and outside of the cell
7.2 inside the cell and 7.4 outside of the cell
What is the concentration of Cl- within the cell and outside of the cell?
5-15 mM inside and 110 mM
What molecules can freely pass through the lipid bilayer?
Water and small non-polar molecules like O2
What are the two major classes of membrane proteins?
Carrier proteins (conformational change) and channel proteins (water filled)
Describe passive transport (facilitated diffusion).
Passive transport occurs by diffusion down an electro-chemical gradient
Describe active transport.
Active transport utilizes energy move molecules up their electrochemical gradient (moves molecules from low to high concentration area).
What are the three forms of energy used in active transport?
Light, ATP, and the energy of another molecule moving down its electro-chemical gradient (coupled transport)
What are the three types of carrier mediated proteins?
Uniport - moves a single molecule, symport - moves two molecules in the same direction, antiport - moves two molecules in opposite directions.
What ion gradient is used to take up nutrients in animal cells?
Na+ ions are co-transported with glucose into the cells and then pumped out by the Na+ K+ pump
What chemical causes cells to burst by deactivating a pump, name the pump as well.
Oubain causes the Na+ K+ pump to stop functioning which throws off the osmotic balance of the cell.
Describe ion channels.
Ion channels are usually selective and gated. They are passive, but can be gated by voltage, mechanics, or ligans.
What are the six cell membrane junctions?
tight junction, adherens junction, desmosomes, gap junctions, and hemidesmosomes.
What is the function of a tight junction?
A tight junction seals neighboring cells together in an epithelial that prevents the leakage of molecules between them.
What is the function of a adherens junction?
Joins an actin bundle in one cell to an actin bundle in a neighboring cell
What is the function of a desmosome?
joins the intermediate filaments in one cell to those in a neighbor
What is the function of a gap junction?
Allows the passage of small water soluble ions and molecules in the cytosol.
What is the function of a hemidesmosome?
anchors intermediate filaments in a cell to the basal lamina
What are the two proteins involved in tight junctions?
Occludin and claudin
What molecule links the two cells together in an adherens junction?
What structures are cadherins linked to within the cell?
actin filaments
What fibers are connected by desmosomes?
Desmosomes use a different type of cadherin to bind to keratins
What are hemidesmosomes attached to?
Hemidesmosomes attach keratin inside the cell to integrin proteins bound. These integrin proteins are bound to laminin proteins found in the basal lamina
Desomosomes and hemidesmosomes always attach to what filament within the cell?
What do gap junctions allow to travel between cells?
small molecules
What is the diameter of a gap junction?
1.5 nm
what protein makes up gap junctions?
What regulates the permeability of gap junctions?
pH or calcium concentration. An increase in either of these will shut off the channel
Where does all synthesis of protein occur?
In the cytoplasm
What directs the delivery of proteins and where is this marker located?
A sorting signal made of amino acids within the actual protein direct its delivery.
What are the three ways that proteins are transported across membranes?
Through nuclear pores (gated transport), transmembrane transport of unfolded proteins (mitochondria, ER), and vesicular transport by budding and targeted fusion (ER to Golgi, Golgi to secretion vesicles, secretion vesicles to PM, PM endocytosis)
Where does a protein go if it lacks a signaling protein?
The protein remains in the cytoplasm
What determines if a protein can move through a nuclear pore complex?
Nuclear Localization Signals (Proteins)
What must a protein bind to before it can move through a NPC?
nuclear transport receptor
What must occur before a protein can move into mitochondria or chloroplasts?
They must have the correct signal sequence and then denature.
What directs ribosomes to specific locations on the ER?
A Signal Recognition Protein at the end of the gowing polypeptide chain interacts with an SRP receptor on the surface of the ER. The ribosome them "docks" to the translocation channel and the growing chain is synthesized through the channel and into the ER.
Once the SRP binds to the SRP receptor, what happens?
The end of the protein bound to the SRP is then transferred and bound to the translocation channel.
What happends after the protein is finished synthesizing?
The beginning (N-terminus) of the protein (the signal sequence) is still bound to the translocation channel. This must be cleaved to allow the protein to enter the ER. This is accomplished by the signal pepsidase.
What keeps a single pass protein from moving through the membrane into the lumen of the ER?
Similarly to a soluble protein, the N-terminus is bound to the translocation channel, but the movement of the protein thorugh the channel is halted once a stop transfer sequence is reached. The N-terminus sequence is then cleaved off by a signal pepsidase and released into the cytosol of the cell.
Describe the integration of multipass proteins into the lumen of the ER.
A start transfer sequence is stays attached to the protein in the translocation channel and eventually the PM. The protein stops moving through the PM when a stop transfer sequence is reached.
Where does glycosylation occur within the cell?
Glycosylation occurs within the lumen. After vesicular transport to the PM this will eventually become the exterior of the cell.
What is the structure of the Golgi apparratus?
The Golgi is made up of 4-6 pancake shaped cisternae
On what side of the Golgi do proteins and lipids enter?
The cis side
Proteins and lipids are stored in what when the enter the Golgi?
From what side of the Golgi do transport vesicles leave ?
What are the four major classes of hydrolases that are contained within lysosomes?
proteases, nucleases, glycosidases, and lipases
What is the pH inside a lysosome?
At what pH are the hydrolases contained within a lysosome activated? Deactivated?
Activated at pH of 5 and deactivated at a pH of 7.2
Where are lysosomes formed?
What are the two types of endocytosis? Describe them.
Pinocytosis is the ingestion of fluid and solutes in vesicles < 150 nm. Phagocytosis