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Cell Biology
Cel Biology
97
Biology
Undergraduate 1
01/17/2016

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Term
What is a cell cortex?
Definition
The protein network on the inside of the cell membrane much like a cytoskeleton around the edge of the cell. Has spectrin fibres connecting different anchor proteins.
Term
What are endosomes?
Definition
These are the transport packages for digestive enzymes from the golgi apparatus to the lysosomes.
Term
What makes up 30% of all globular protein make up?
Definition
Protein turns and twists. These are what gives the globular proteins their structure and what makes them different from the fibrous proteins.
Term
What is a chaperone?
Definition
These are protein molecules that make sure that proteins will fold properly. They can fold and join up different polypeptide chains and this is what makes the proteins have specific functions.
Term
What is protein domain?
Definition
It is the different areas of a protein but still on the same polypeptide chain.Different domains can have different properties which overall adds up to the proteins complete function
Term
What is a protein motif?
Definition
They are complex structures that secondary structures can produce when interacting specifically to produce. Such as beta sheet barrels and alpha helix corner/turn.
Term
What form of isomers are ALL natural isomers in?
Definition
The L isomer. Not the D isomer, the L isomer.
(Optical isomers)
Term
What is SDS?
Definition
Sodium Decadyl Sulphate.
It is able to react with a folded negatively charged protein to cover it in negative charge. Used in gel electrophoresis so that all proteins travel towards the anode.
Term
How to determine the structure of a protein?
Definition
X-ray crystallography allows us to create electron density map and work out protein backbone and then structure.
Nuclear magnetic resonance allows us to work out the H positions and their bonds to work out overall structure
Term
If the forward reaction has a negative ∆G value then..
Definition
The forward reaction is exothermic
Term
If the forward reaction has a positive ∆G value then....
Definition
The forward reaction is endothermic
Term
What is ∆G?
Definition
Gibbs free energy. Represents the total energy in a system and can show energy changes.
Term
What is proteolytic activation?
Definition
When an enzyme is produced by an active suppressor is added as the enzyme is digestive and destructive. Therefore the suppressor is added until the enzyme is required and the proteolytic activation will remove the suppressor so the enzyme is activated.
Term
What is Vmax?
Definition
It is the maximum velocity/work rate of an enzyme.
Term
What is Km?
Definition
The michaleis constant, it represent the concentration of a substrate at half of the maximum reaction rate of the enzyme?
It tells us the concentration of substrate available and how tightly an enzyme will bind to a substrate.
Term
What is V?
Definition
The rate at which a given enzyme is working.
It can be used to see the changes in environment too as the V will go up or down if the enzyme is favourable or unfavourable environments.
Term
What is the Lineweaver-Burk plot graph?
Definition
A plot of 1/Substrate concentration on the x axis and then 1/V on the y axis.
It can be used to find the -1/Km value where the line of best fit intercepts the x axis and the 1/Vmax is where the line of best fit will intercept the y axis.
Term
What is a micelles?
Definition
A ball of phospholipids that organise themselves due to their amphipathic structure in a liquid medium and will only form when the surroundings are at a specific surfactant concentration.
Term
What is the Critical Micelles Concentration?
Definition
The specific concentration of surfactants that has to be in place for the formation of a micelles.
Term
Amphipathic?
Definition
When a molecule has both polar a non polar groups.
A phospholipid is an amphipathic molecule.
Term
What are other polar heads that may be present on a phospholipid instead of phosphate?
Definition
Choline, Ethanolamine and Serine
Term
Why do majority of membrane proteins never leave the membrane?
Definition
They are amphipathic molecules and their middle segment that s burned in the membrane is hydrophobic and will not leave the bilayer.
Term
What is band 3 protein in the erythrocyte cell membrane?
Definition
It is the anion channel and is very involved in the moving of oxygen in and out of the tissue.
Term
What is a membrane raft?
Definition
These are sites of high transport and communication protein and cholesterol concentration. In the membrane they have been found to have more active sites than the other part of the skeleton for signalling and endocytosis.
Term
What is Valinomycin?
Definition
It is a complex molecule that is able to carry potassium ions through membrane walls. This is because it is amphipathic and it has hydrophobic outside and can move through.
Term
What is Gramicidin?
Definition
It is a channel for potassium ions which supposedly slides to open.
Term
What is the nernst equation?
Definition
It describe the relationship between the voltage across a membrane and the solute gradient.
It represents the magnitude of a membrane potential at equilibrium or at any point.
Term
In the Nernst equation, what do the constants roughly add up to?
Definition
-60mV
Term
Coupled transport?
Definition

The ion gradient of an ion is used to drive the transport of another ion that has not got enough of a gradient and the two ions cross together

Also known as secondary active transport.

Term
What is secondary active transport?
Definition
It is when a ion gradient is formed by active transport to use for coupled carrier transport which only works due to the high ion gradient. This coupled transport then uses a carrier to get across the membrane. This career coupled transport is called secondary active transport as the primary active transport was to produce the ion gradient in the first place.
Term
What are gap junctions
Definition
When two membrane transport proteins from two cells bond and a channel former between two cell cytosols. Used for cell to cell communication.
Term
What is a Signal/Leader Protein?
Definition
A small protein sequence will bind to a larger protein and then will attach to a larger molecule (the one that needs to enter the mitochondrial matrix) and the signal protein will bind to a receptor on the mitochondrial outer membrane to allow a channel big enough to open and using a lot of ATP the cell that was needed in the cell is release and assembles and then protease removes the signal protein from the peptide chain and are all separated in the matrix of the mitochondrion.
Term
What is a TOM complex?
Definition
A Transporter Outer Membrane. A transport protein complex in the mitochondrial outer membrane.
Term
What is a TIM complex?
Definition
A Transporter Inner Membrane. A transport protein complex in the mitochondrial inner membrane.
Term
What is a clatharin coated pit?
Definition
It is what is used for endocytosis. It has inner receptors that are embedded into the cell membrane, cargo molecules will bind to these receptors and then the the clatharin coated pit will close up into a ball type shape, taking the membrane with the receptors in with it and then will love not the cell carrying the cargo molecules and then it will breakdown and release the molecules into the cytosol. A molecule called dynamin is used to cut of the membrane with the membrane taken in the clatharin coated pits. Not all endocytosis is done this way. Cargo molecules can be LDLs.
Term
What are the steps of Glycolysis?
Definition
[image]
Term
What are the basic structure steps of glycolysis?
Definition
Glucose -> Fructose 1,6-biphosphate -> 2x glyceraldehyde 3-phosphate -> 2x Pyruvate
NET of 2 ATP and 2 NADH molecules produced
Term
What are the to glucose phosphorylation enzymes?
Definition
Hexokinase - In the brain
Glucokinase - in the liver
They both phosphorylate the glucose in the first step of glycolysis
Term
What anticancer drug could be administered that inhibits glycolysis?
Definition
Careful dosage off arsenic will block the between glycoaldehyde 3-phosphate and the pyruvate.
Term
How does pyruvate enter the Krebs/citric cycle?
Definition
Enters the mitochondrial matrix and then is decarboxylated by oxygen to form CO2 and then NAD+ dehrydrogenates the molecule to form NADH and then the molecule attaches to the Coenzyme A and Acetyl CoA is put into the Krebs cycle.
Term
Krebs cycle NET gains?
Definition
1 ATP
1 FADH2
3 NADH + 3 H+
2 CO2
2 e- to the electron transport chain
1 GTP
Term
What is oxidation?
Definition
Loss of electrons and loss of hydrogen
NADH --> NAD+
Term
What is reduction?
Definition
Gain of electrons and gain of hydrogen
NAD+ --> NADH
Term
How is FADH produced?
Definition
FADH is an important hydrogen carrier and its form of FAD is reduced and two hydrogens are added to form FADH
Term
What is succinate dehydrogenase?
Definition
It is an enzyme that dehydrogenases the succinate molecule in the Krebs cycle to form FADH2 and Fumarate.
This physically occurs in the electric transport chain and is represented with a Q as it is a ubiquinone.
Term
Which way will an electron jump on the redox scale?
Definition
It will jump from a low to a high potential. This means that a low potential pair has a lower affiliation.
Term
What did Peter Mitchell bring into the world of science?
Definition
He brought the theory of oxidative phosphorylation
Term
What is coupling?
Definition
It is the special case of active membrane transport
Term
What is the Nernst Equation in simplest form?
Definition
Eh = Em - Log(reduced/oxidised)
Eh being the redox potential
Em being the midpoint potential
Term
What is the path of electrons in the electron transport chain?
Definition
Complex I -> Complex II -> CoQ -> Complex III -> Cyt -> Complex IV
Complex I - NADH oxidoreductase
ComplexII - Succinate oxidoreductase
Complex III - Ubiquinol oxidoreductase
Complex IV - Cytochrome reductase
Term
What is the calvin cycle?
Definition
It is the cycle in the chloroplasts that takes in CO2 and adds it to RuBP to form 3-Phosphoglycerate and then this form the starch and fatty acids and sucrose.
This cycle continues and receives the ATP and NADPH from the photosynthesis reaction for energy and reducing power
Term
What is the path of electrons in the photosynthesis electron transport chain?
Definition
Broken from H2O being split -> Into Photosystem II -> Platoquionone -> cytochrome -> Plastocyanin -> Photosystem I -> Ferredoxin -> Ferrodoxin NADP reductase, this is where it is added to a NADP and H+ molecule to reduce NADP to NADPH which gives it a higher redox potential and then goes to the calvin cycle
Term
What do plastoquinones do?
Definition
They are insoluble in water but soluble in membranes so they are used in electron transport chains to move electrons to proteins
Term
What is ∆p?
Definition
This is the proton motive force.
∆p = -∆ψ + ∆pH
∆ψ = The Electrical gradient
∆pH = The distribution of H+ ions over across the membrane
Term
What is the basal leak?
Definition
This is the leak of protons from the intermembrane space back into the matrix and lower the proton gradient for the ATPase. Said to have possible evolved to limit the ∆p.
The proton leak is around 20-30%
Term
How can you measure the mitochondrial respiration rates?
Definition
Using a polargraphic oxygen electrode. Uses a platinum and silver electrode and the oxygen that comes into contact with the electrode is reduced and the current passed on is proportional to the partial pressure of O2 and is recorded on PC
Term
What is DNP?
Definition
Dinitrophenol which is an uncoupler an increases metabolic rate largely.
Term
What is the pH in mitochondria?
Definition
The pH is low due to the high concentration of H+ ions. It is lower in the cytosol because of the being actively pumped into the cytosol despite theatres action and the basal leak. The low pH drives H+ back into matrix which reinstates the effect of the membrane potential.
Term
What is ROS?
Definition
It is the Reactive Oxygen Species. They are chemical reactive molecule containing Oxygen. These are used in normal cell biology and cell signalling but a build up can be damaging.
Term
What are free radicals?
Definition
Uncharged molecules with an unpaired electron. These cause damage to cells. High levels of free radicals will cause increased rate of cell damage an cell death.
Term
What is the effect of ROS on eye?
Definition
Caractognesis and retinal damage
Term
What is the effect of ROS on Skin?
Definition
Dermatitis and ageing pigment
Term
What is the effect of ROS on Heart?
Definition
Heart attack
Term
What is the effect of ROS on joints?
Definition
Arthritis
Term
What is the effect of ROS on lung?
Definition
Asthma and hyperoxia
Term
What is the effect of ROS on Brain?
Definition
Trauma and stroke
Term
What is the effect of ROS on gastro intestinal system?
Definition
Hepatitis and liver injury
Term
What is the effect of ROS on teeth?
Definition
Peridontis
Term
What is the effect of ROS on Vessels?
Definition
Atherosclerosis and vasospasms
Term
What is the effect of ROS on multiple organs?
Definition
Cancer can arise from high concentrations of reactive oxygen species
Term
What are the specifics with transmission electron microscopy?
Definition
Resolution 2-20nm, specimens fixed, dehydrated and stained with heavy metals, also freeze-fracture can be used instead
Term
What is a liposome?
Definition
Like a micelles but with a phospholipid bilayer instead of just one layer of phospholipids
Term
What are the specifics of a Scanning electron microscopy?
Definition
Resolution 10nm, samples fixed, dehydrated, and stained with metal, normally gold
Term
How many cells does the average human have?
Definition
5x10^13
Term
What is papain?
Definition
An enzyme used to tenderise cheap steak form papaya.
Term
Oxidoreductase
Transferase
Hydrolase
Lyase
Isomerase
Ligase
Polymerase
Definition
Oxidise/reduce
transfer chemical group
Hydrolytic cleavage
Remove chemical group
Rearrangement
Joining
Polymer synthesis
Term
What is transgluaminase
Definition
An enzyme that is used to bind to protein based structures together in cooking. (Meat glue)
Term
What is streptokinase?
Definition
Given to stroke victims as it is able to phosphorylate the human plasminogen to plasmin which is able to quickly breakdown the clots int he blood. The enzyme is however seen as foreign by antibodies and is therefore resisted. This is why it is replaced with tPA.
Term
What happens when you expose pure protein to concentrated urea?
Definition
The protein completely unfolds and denatures.
But when you remove the urea the protein goes back to the original shape
Term
How can you use enzymes as an anti drug for cancer?
Definition
Cancer cells have a form of Pyruvate kinase called PKM2 and this has medium activity as to balance the substrates to be able to continue functioning. You can engineer a PKM2 activator to stimulate faster pyruvate production to run the cancerous cells out of product so no cell growth can occur
Term
How many types of cell are there in humans?
Definition
Around and about 200.
Term
What is the glycocalyx?
Definition
It is a sugar based structure of acting round some cells that will provide chemical protection and provides information for recognition of cell to cell communication.
Term
What is glyconeogenesis?
Definition
It is the act of taking pyruvate and building it up to form glucose-6-phosphate which can then enter the blood for transport to the target tissue
Term
What is a GPCR and how does Ca2+ get involved?
Definition
They are G protein coupled receptors. Large group of '7TM receptors' and they are involved with opening Ca2+ channels when stimulated. They can also be stimulated by Ca2+ ions as well as many other things and then the receptors induce actions of alpha protein messengers in the cell.
Term
What the stage of a cell cycle and how long does it take?
Where are the checkpoints?
Definition
G1 - 6-12hrs
S - 6-8hrs
G2 - 3-4hrs
Mitosis - 1hr
Total - Around 24 hrs (can be much faster
major checkpoint close to end of G1 and then smaller at G2 and M
Term
What is the CDC28?
Definition

A gene that encodes for key regulators in the cell cycle known as protein kinases. Kinases are phosphorilators.

This version is presnt in budding yeast

Another version is CDC2 which is preset in fission yeast.

Human equivalent is CDK1.

 

Term
What is CDK1?
Definition
It is a gene that code for a protein kinase that regulates the cell cycle.
Term
What are cyclins?
Definition
Cyclins are small proteins in the cell that will regulate the cell cycle regulatory proteins (protein kinases). They occur during periods of the cell cycle and are then disintegrated when not in use
Term
What does CDK stand for?
Definition
Cyclin Dependent Kinases.
These are the protein kinase phosphorilators that regulate the cell cycle
Term
How many CDKs control the human cell cell cycle and how many cyclins control those CDKs?
Definition
6 types of CDK
11 types of cyclin
Term
What does penicillin bind to when in the cell?
Definition
Bacterial transpeptidase (DD-transpeptidase)
Term
What is Differential interference contrast microscopy?
Definition
Uses rate of change in refractive index. Produces apparent 3D images
Term
What does Clavulanic acid bind to and what does it do?
Definition
It binds to ß-lactamse and inhibits its action. ß-lactamase is the reason for penicillin resistance in a lot of bacteria so if they work together, penicillin and clavulanic acid are better at destroying bacteria.
Term
Confocal scanning light microscopy
Definition
Uses laser beam to scan successive single planes of specimen stained with florescent stain
Term
All natural amino acids are in the ... isomer form?
Definition
The L Isomer Form
Term
What is meant by the term augmentin?
Definition
It is when two enzymes work together
Term
What is the allosteric site?
Definition
Non competitive enzyme interaction in which a molecule different to the substrate will bind to and will change the active site shape for example for good or for bad.
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