2CB3 Cell Bio Exam Review

1. cells are highly complex and organized

2. cells posses a genetic program and the means to use it

3. cells can produce more of themselves

4. cells acquire and use energy

5. cells carry out a variety of chemical reactions

6. cells engage in mechanical activities

7. cells are able to respond to stimuli

8. cells can self-regulate

9. cells can evolve

Eukaryotes:

• are multicellular and have membrane bound organelles

• has a nucleus and nuclear division and is separated by a nuclear envelope

• is a diploid so have two copies of genes

• have complex flagella and cilia

• has mitochondria and chloroplasts

Prokaryotes:

• unicellular and no membrane bound organelles

• has no nucleus

• is a haploid

• has simple flagella and cilia

• no mitochondria or chloroplasts

they are protein complexes responsible for the degradation of un-needed or damaged proteins by proteolysis (the breaking of peptide bond). enzymes that help this reaction are called proteases.

3, bacteria, archaea and eukarya in Archaea there are thermophiles, acidophiles, methanogens and halophiles.

is a prokaryote that is the smallest and simplest. It has no cell wall and is thus resistant to antibiotics since antibiotics attack the cell wall.

• E.coli us great for genetic manipulation and is rod shaped

• Yeast is least complex of eukaryotes used to study proteins homologous to human cells (metabolic, neurodegenerative)

• wheat is used for its short generation time, large seed production and height of a few inches

• C.elegans has a defined number of cells (1000), easy to control, precise pattern of cell division, transparent body walls and short generation time

• fruit fly turn into adults in 10 days

• house mouse are good for cancer and also due to their size

Its is an undifferentiated cell that can self-renew and is multi-potent so it can differentiate into 2+ mature cell types.

Is a pluripotent stem cell but cannot turn into the placenta and umbilical cord. They can also self-renew in culture. They can turn into benign tumours known as teratomas.

When a differentiated cell is reprogrammed into another differentiated cell without undergoing the pluripotent state. Acinar cells from the pancreas are transformed into pancreatic beta cells (which produce human insulin) in diabetic mice. To do this 3 genes from a virus will be injected into the acinar differentiated cell and thus it will be involved in the differentiation of beta cells in diabetic mice. They are thus transdifferentiated into a beta cells.

20000 Å

• Small naked RNA molecule (no protein coat)

• Doesn't need to inject into host

• will interfere with gene expression in host

Virion, has a coat

Viruses have surface proteins that bind them to the surface of the host. They have viral specificity and will infect a hosts specific cells depending on its surface proteins.

It involves the sharing of electrons between two atoms

Is where the sharing of electron is unequal and there is a partial charge present on each side of the molecule

Electrons are equally shared between atoms.

Have attractions that are weaker than a covalent bond. Doesnt depend on electron sharing , Depends on attraction between opposite charges. On their own are weak bond, 1-5 kcal, that break and reform.

Aids in dynamic cellular processes. Individually they are weak but collectively they can provide structural stability. Ex the 2 DNA strands

Is electrostatic force between fully charged atoms. Gets weaker in presence of water. Stronger in the core of a proteins. Ex: Phosphate atoms, -ve charge, from DNA are closely associated with +ve charged groups on a protein

When a covalently bonded hydrogen (+ve charge) of one molecule is attracted to the electrons of another molecules atom. Determines structures and properties of water. Ex: The bonds between the 2 stands of DNA

Intermolecular forces (forces between 2 separate molecules) between hydrophobic molecules and water. The hydrophobic molecules will form in a way that will limit their interaction with water. Is not a true bond. Significant within larger biological molecules (away from water). Due to dipoles. Sensitive to the distance between 2 atoms/molecules.

• Carbohydrates

• Lipids

• Proteins (polymers of amino acids)

• Nucleic acids (polymers of nucleotides)

Used for energy storage and structural support. Can be used for biochemical signature on cell surfaces. Participates in cell recognition and structural roles. Chemical Formula: (CH2O)n

Sugar that has a carbonyl (C=O) on internal carbon

Sugars with carbonyl (C=O) on terminal carbon

Usually linear but sometimes cyclic

Due to the reaction of a keto or aldehyde group with hydroxyl group

He will need to get a HbA1c test done from the laboratory. This test will react the linear from of sugar with a protein molecule, if there is too much sugar in the blood the cyclic from of the molecule will not occur, rather it will react with the hemoglobin in the blood and will from a A1c haemoglobin molecule.

The linear form of sugar with react with the hemoglobin protein (A1c) in stead of the cyclic form

Branched animal product ~ alpha(1-4) strand with alpha(1-6) branch points, is the most branched, branched glucose polymers

Branched plant product ~ made up of branched Amylopectin with unbranched amylose, mostly alpha(1-4), helical in structure

Unbranched structural polysaccharide of plant product ~ unbranched glucose polymer beta(1-4), is linear

Alpha helices:

• right hand coil, rod like

• hydrogen bonds parallel to polypeptide backbone

• hydrogen bonds between NH group and C=O of amino acids

• only one type and exists in a single chain

• R groups of amino acids are outside of helix

• Ex. DNA, hemoglobin

Beta Sheets:

• sheet like

• hydrogen bonds are perpendicular to polypeptide backbone hydrogen bonds between neighbouring NH and C=O of adjacent peptide chains

• can be parallel, antiparallel or both

• R groups of amino acids are both inside and outside of sheet

• Ex. Silk

Using detergents (SDS), organic solvents, radiation, heat, change in pH, urea

To study diseases

Is a neurodegenerative disorder that results in dementia, disorientation, confusion, etc. Due to mis-folding of proteins. Amyloid hypothesis: effect in gene plaque (beta-amyloid) formed which causes signal conduction to stop Taupathies: Tau protein enters neuron and causes plaque buildup (beta-amyloid) which sops signal conduction

Loss of heat is exothermic. Gain of heat is endothermic.

GIbbs free energy

+ve delta G is non-spontaneous and increase in free energy of system and decrease in entropy of universe -ve delta G is spontaneous and decrease in free energy of system and increase un entropy of universe

Entropy: decrease in free energy favours product formation which increases entropy

Electrostatic Repulsion: the adjacent negative charges of oxygen in ATP repel each other

Resonance stabilization of products: resonance stability of ADP and Pi is greater than ATP

Solvation of ADP, Pi and H+ id higher than ATP since ATP can lose its phosphate group easier than ADP can

Enzymes are biological catalysts

• they are not prominently altered during a reaction

• they cannot effect the thermodynamics of a reaction (dont supply energy for reaction and doesnt determine reactants:product ration at equilibrium

• are highly specific

• they lower activation energy

• lower temperatures can lower activation energy and more molecules can react, this can also be applied to pH

• enzymes may not work in certain pH or temperatures

• present in cells in small amounts

Both act as a "key" to start the reaction, will bind and activate an enzyme (inactive enzyme, no cofactor/coenzyme, is a apoenzyme). Cofactors are inorganic (metals), coenzymes are organic. Enzyme with cofactor is a holoenzyme

Lock and Key model: enzyme is stiff and substrate fits in perfectly, like a lock and key (hence the name) Induced Fit model: the enzyme will change to fit the substrate Enzyme-Substrate complex will bind using non-covalent forces Substrates are specific to enzymes due to chemistry of active site

Is an inhibitor which binds tightly to enzyme through a covalent bond Ex. nerve gas

inhibitor that binds loosely to enzyme, non-covalently. Two types competitive and non-completive

Compete with substate for active site. Can be overcome if there is more substrate than inhibitor.

• Increases Km without affecting Vmax Ex. ACE inhibitor that stops angiotensin II from binding to ACE and thus will lower blood pressure

Does not bind to active site but instead binds to the allosteric site and will change the shape of the enzymes active site. Cannot be overcome with higher substrate to inhibitor ratio

• Decreases Vmax without affecting Km

• Ex. Tipranavir with inhibit the anti-retroviral protease inhibitor and is used for prevention and treatment of HIV

A) glycolysis since it is a BREAK down of glucose

• gluconeogenesis is the making of glucose from non carbohydrate sources

(protein) kinases add a phosphate group to other proteins/molecules

• Phospholipids

• Sphingolipids

• Cholesterol

Neutral glycolipid with an uncharged sugar a a head group. Present in brain and nerve cells

Has a oligosaccharide head group with 1 or more -ve charged sailic acid residues. Present in brain and nerve cells People who cannot synthesize this (G M3) suffer for a neurological disease that causes seizures and blindness

They are based on the glycolipids since they have an enzyme that adds N-acetylgalactosamine to the ends of RBC membrane glycolipids. A lack of these proteins results in the O-blood group

RBCs were treated with phospholipase. Since different lipids have different properties so each leaflet will have different properties. Responsible for the asymmetry of a membrane

can identify transmembrane segments of known amino acid sequences from integral proteins

Higher temperatures make the membrane more fluid, lower temperatures does the opposite. The more unsaturated (shorter chain) the more fluid.

The lipid is more rigid as it it is converted into a frozen crystalline gel.

The lipid content of the sample taken in the summer will be higher than the lipid content of the sample taken in the winter. In the winter the membrane will be more unsaturated, making the membrane more fluid but due to the lipids crystallizing the membrane will be more rigid. In the winter the membrane will have more double bonds to make it fluid to counteract the effects of the cooler temperature. This would be the opposite in the summer.

• Increasing the number of double bonds by desaturating single bonds, catalyzed by desaturases

• reshuffling of chains between different phospholipid molecules that to make them have 2 unsaturated fatty acids

Through the flipase enzyme

1. simple diffusion through bilayer

2. simple diffusion through aqueous channel

3. ion diffusion channels

4. facilitated diffusion

5. active transpost

Relies on molecular size and polarity. Smaller molecules penetrates the lipid bi-layer faster than larger ones, polar molecules (sugars and amino acids) poorly penetrate membranes, greater the lipid solubility the greater the penetration

ATP is needed for this transport to occur. Ex. the sodium-potassium pump (ATPase) needs ATP to function and let in 2 potassium and let out 3 sodium. The ATP is phosphorylated/hydrolyzed for the diffusion to occur

They are chemicals created and released from the presynaptic cleft and diffuses into the postsynaptic cleft

They cab depolarize (excite) or hyper-polarize (inhibit). They bind to ion channel receptors and simulates/inhibits function

Their action is terminated by re-uptake or enzymatic breakdown

They act as sodium channel blockers by blocking the ion channels in the membrane of sensory cells and neurons. This results is the inhibition of the action potential of the affected cells (skin or teeth) and the brain does not receive info about the stimulus.

Neurotransmitters can be eliminated through enzymes that will destroy the neurotransmitters in synaptic cleft and the neurotransmitter re-uptake process. Ex. cocaine inhibits the re-uptake of dopamine in the synaptic cleft which causes a short feeling of euphoria and makes one want to repeate the activity

The cristae is the inner boundary membrane of the mitochondria. The cisternae is a network of flattened sacks found in the RER and golgi

Cytoplasm of a cell

Matrix of mitochondria

Inner mitochondrial membrane

First step occurs in the cytoplasm and doesnt use oxygen (anaerobic). Glycolysis will produce 2 pyruvate, 2 NADH and net 2 ATP per glucose. Most of the energy is in pyruvate. ATP is produced by substrate-level phosphorylation

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Holoenzyme has a cofactor while an apoenzyme does not

holoenzyme

apoenzyme

1. Flavoproteins

2. Cytochromes

3. Copper atoms

4. Ubiquinone

5. Iron-sulphur proteins

Are polypeptides bound to FAD and FMN which can donate 2p+ and 2e-. Major flavoproteins are NADH dehydrogenase of the ETC and succinate dehydrogenase of the TCA. They are found in the mitochondria

Contain heme prosthetic groups having Fe or Cu ions. Found in the cristae of mitochondria. Cytochrome c is a soluble protein found in the inter-membrane space and is apart of the ETC.

Also known coenzyme Q which is lipid soluble. Able to accept 2e- and 2p+

Complex I: NADH dehydrogenase, is a catalyst for the transfer of e- from NADH to ubiquinone and transports 4H+ per pair of e-

Complex II: succinate dehydrogenase, catalyst for transfer of e- from succinate to FAD to ubiquinone without H+, used in both TCA and ETC

Complex III: cytochrome bc1, catalyst for the transfer of e- from ubiquinone to cytochrome c and transports 4H+ per pair of e-

Complex IV: cytochrome c oxidase, catalyst for transfer of e- to O2 and transports 2H+ per pair of e- across inner membranes

no

Carries out electron transfer and proton translocation

NADH --> FMN --> 7Fe-S complexes --> UQ

Dysfunction is linked to neurological diseases

Background: deltaP is pH gradient which is the conc. gradient of H+ ions between matrix and inter-membrane space; the separation of charge across the membrane created a electric potential (trident symbol); are components of proton gradient The energy present in both components is the proton-motive force (deltaP)

The doctor found that the patient was using uncoupling proteins to his advantage in weight loss, but due to protein uncoupling drugs such as DNP causing electrons to be sent back into the matrix which dissipates the gradient created by the electron transport chain which releases energy; this can account for the loss of energy in the patient.

2 parts; F1 and F0 F1 is the catalytic subunit and has three catalytic sites (3 alpha, 3 beta and 1 gamma) for ATP synthase, has 5 subunits ~ 3 alpha, 2 beta, 1 delta, 1 epsilon and 1 gamma F0 attaches to F1 and contains a channel that allows p+ to be conduced from inter-membrane space to matrix, has 3 subunits ~ 1a, 2b and 10-14c

The coupling of H+ translocation to ATP synthase

Are oxidative organelles which breakdown toxic material in cells through the presence of at least 50 digestive and oxidative enzymes. They also contain catalase (decomposes hydrogen peroxide). causes Zellweger syndrome (ZS) wich results in neurological, visual and liver issues that lead to death in infants

Contains thylakoids in stacks known as granum. Also contains enzymes responsible for carbohydrate synthesis. Also contains small double stranded DNA and ribosomes

Mg+ ion is central to chlorophyll molecules

Light dependant: sunlight is absorbed that converts ATP into NADPH Light independent: uses energy in ATP and NADPH to make carbohydrates

An electron from H2O enters PSII which boosts e- from below energy level of H2O then it moves to PSI which boosts the e- to a level above NADP+. This process of flow of e- from H2O to NADPH+ is called the Z scheme

PSII is responsible for the catalyzation of the light driven process that reduces water and reduction of plastoquinone(PQ). The process starts when light is absorbed by the outer antenna pigment LHCII. Then Pheo- is generated which will transfer e- to PQA and then to PQB to for the negatively charged radical PQB-. The second photon is absorbed and a second electron will be sent through the path mentioned above creating PQB2-. After this photons will enter from the stroma and make plastoquinol (PQH2). Then this complex will diffuse through the thylakoid membrane to bind to cytochrome b6f and will donate its e-. This complex will donate its e- to plastocyanin that will carry e- to PSI to make P700+

Light is absorbed by LHCI and passed to P700. This leads to the making of P700- and chlorophyll a (A0-). Then the NADP+ is catalyzed by the enzyme Ferreodoxin-NADP+ reductase, which contains a FAD prosthetic group and accepts 2e-

Plastocyanin will carry e- to the luminal side of PSI and then transfer these e- to P700+

To reduce NADP to NADPH

There are 8 photons absorbed and the following reaction occurs: 2H2O + 2NADP+ --> O2 + 2NADPH