Eukaryotic Cell
What is the major difference between a eukaryotic and prokaryotic cell?
Eukaryotic Cells possess membrane bound-organelles
What is cellular metabolism?
Sum of all the reactions that occur in a cell which involve the transfer/usage/production of energy.
What molecule must be present for pyruvate oxidation to occur?
O2
Which part of Cellular Respiration is responsible for the largest amount of ATP production?
Oxidative Phosphorylation
The model that best describes the cell membrane is...
Fluid Mosaic model
Name 5 organelles that are part of the endomembrane system.
Nucleus, Rough ER, Smooth ER, Golgi, Lysosomes, Vacuoles, Peroxisomes
Use the first law of thermodynamics to explain the Proton Motive Force
Electrochemical gradient produces high PE state; chemiosmosis of the protons releases the energy of the gradient; the released energy is used to synthesize ATP
All the Energy is accounted for.
How does glycolysis produce ATP?
What type of reaction allows the TCA cycle to produce high energy electron carriers?
Oxidation
In session, we discussed several components of the cell membrane. List at least 3 of these components.
Phospholipid bilayer, integral and peripheral proteins, glycoproteins, glycolipids, cholesterol
Explain using characteristics whether eukaryotes or prokaryotes evolved first.
Prokaryotes are smaller, have smaller genomes, lack membrane bound organelles, and are overall simpler.
Simpler = evolved first (usually)
How does the cell complete reactions that are nonspontaneous?
1) Reaction coupling
2) Enzymes
How many net NADH and ATP are produced in glycolysis and pyruvate oxidation.
Glycolysis: 2 ATP + 2 NADH
Pyruvate Oxidation: 1 NADH x2 per glucose = 2 NADH
Total: 2 ATP + 4 NADH
How many NADH and ATP are produced per glucose molecule in the TCA cycle.
TCA Cycle: 3 NADH + 1 ATP
TCA Cycle x 2 per glucose = 6 NADH + 2 ATP
Explain how the properties of the cell membrane allow it to be selectively permeable.
Cell membrane is a phospholipid bi-layer which means heavily charged or polar substances cannot easily cross the hydrophobic regions.
Cell membrane is relatively tightly spaced which means large (even nonpolar) molecules cannot easily cross.
What three pieces of evidence support the endosymbiont theory of chloroplasts and mitochondria ?
1) They are both double membraned - similar to gram negative bacteria
2) They both contain their own genetic information and specific enzymatic machinery
3) They replicate independently of the cell
1) Organic catalysts = not consumed in the reaction
2) Catalyze only one reaction
3) Stabilize the transition state of a reaction
What is the purpose of fermentation?
Recycle high energy electron carriers; without respiration, NADH and FADH2 would not be oxidized back to NAD+ and FAD+
A researcher is observing the metabolism of a mutant cell. She notices that the normal quantity of high energy electron carriers as well as normal release of water as a byproduct from the ETC. Yet there is a significant deficiency in the amount of ATP produced. What mutation would explain these observations?
Cell has mutant ETC Protein Complexes 1, 3, and 4; these complexes are not pumping protons into the intermembrane space so no proton motive force can be used to produce ATP.
Describes the types of cellular transports discussed in class and how they are different
Diffusion: passive transport of materials down concentration gradient; does not require energy; does not require proteins
Facilitated Diffusion: passive transport of materials down concentration gradient assisted by cellular proteins; does not require energy; requires transport proteins
Active Transport: transport of materials against concentration gradient; requires energy; requires transport proteins
Type 2 diabetes is often called insulin-independent diabetes as despite production of insulin, blood sugar levels are not maintained properly. This is often due to the insulin protein being mutant or abnormal. Based on your understanding of the eukaryotic cell, which organelle(s) could be responsible for this abnormal insulin?
1) Nucleus: mutant DNA or incorrect transcription
2) Rough ER: incorrect translation of mRNA
3) Golgi Apparatus: incorrect packaging and/or post-translational modifications
4)Plasma Membrane: mutant cell surface receptors
Explain how ATP is used to power endergonic reactions.
1)ATP has a very high PE due to 3 phosphate groups sitting next to each other - 3 massive negative charges create huge electrostatic and steric repulsions.
2)Hydrolyzing ATP reduces that PE and converts it to usable energy for the reaction
(Some reactions involve phosphorylation of the substrate - this raises the energy of the reactant to above the product and produces a favorable reaction)
A researcher is observing the metabolism of a mutant cell. He observes that despite normal glycolysis occurring and the presence of O2, the cell does not progress to the TCA cycle. He further observes that all the enzymes involved in the TCA cycle are normal as well. Explain the mutation that could cause this observation.
1) Inability to oxidize pyruvate
2) Mutant Coenzyme A
Explain, in detail, how an FADH2 molecule is used to produce ATP
1) FADH2 is produced TCA cycle
2) FADH2 releases its proteins to ETC Protein Complex 2
3) The electrons travel from complex 2 to complex 3 to complex 4
4) Complex 3 and 4 pump protons into the intermembrane space
5) ATP synthase uses the electrochemical gradient generated by these protons to synthesize ATP - Proton Motive Force
What three factors can affect membrane fluidity and how? Explain in detail.
Temperature: higher temperature means more fluid
Amount of unsaturated vs saturated fatty acids: more unsaturated means more fluid
Presence of cholesterol: promotes fluidity at low temps and restricts fluidity at high temps