BI110 Lecture Notes - Lecture 14: Amphiphile, Coenzyme Q10, Phagocytosis
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November 5, 2013
Biology Midterm 2 Review
Which statement is not true for enzymes?
A: they make an endergonic reaction proceed spontaneously.
Which is an inorganic enzyme helper?
A: a cofactor.
- Coenzyme is an organic helper.
Which of the following statements describes the enzyme cycle?
A: after catalysis, enzymes are released unchanged to bind another substrate.
Which of the following statements is NOT true of an enzyme-catalyzed reaction:
A: an enzyme catalyst is necessary because the reaction is not spontaneous.
True: -enzymes helps the reaction get to the transition state.
- Some enzymes need cofactors, like vitamins (vitamin deficiency).
Which has a shape similar to an enzymes substrate?
A: a competitive inhibitor.
Which factor does not affect enzyme activity?
A: free energy.
Factors that don’t: temperature, pH, and substrate concentration.
Which statement about feedback inhibition is true?
A: it involves allosteric binding of pathway end products to early products of enzymes.
Which statement about enzyme activity is not true?
A: increasing the temperature of the enzyme in the reaction will destroy the enzyme
- As the temperature increase, the activity of the enzyme will increase as well.
Why do phospholipids spontaneously assemble into bilayers in aqueous
A: they are amphipathic.
Also true: the hydrophobic effect.
Which of the following statements is not true of desaturases:
A: their expression is increased at higher temperatures.
Which of the following is not a function of membrane proteins?
A: diffusion barrier.
Membranes with higher amount of saturated fatty acids will remain fluid and
functional higher temperatures:
Desaturases remove hydrogen atoms from the phosphate groups of phospholipids:
At low temperatures, sterols restrain the movement of membrane lipids:
- Sterols are attached to the hydrophilic heads- they’ll hold it together it terms of
high temperature, not low temperature.
Which of the following is true about activation energy?
A: it is a kinetic barrier to spontaneous reactions.
Which statement correctly describes a catalyst?
A: it speeds up a chemical reaction.
Which is not a shared feature of peripheral and integral membrane proteins?
A: multiple stretched of 17-20 amino acids.
Which of the following would likely cross the membrane through simple diffusion?
A: oxygen and carbon dioxide.
Which describes aquaporin?
A: They form a substrate-specific hydrophilic channel.
** Know hydrophilic and hydrophobic questions.
Which is not true of secondary active transport?
Which statement about exocytosis is false?
A: it is often called pinocytosis.
Which is not associated with cell signaling using surface receptors?
What would happen to an animal cell it is was placed in a beaker with a hypertonic
A: the cell would shrink.
Which of the following statements is false?
A: cells can’t measure the ratios of products to reactants.
Enzymes function by:
A: acting as a catalyst by increasing the rate of the reaction.
During catalysis of a reaction by an enzyme a transition states is formed. Which
mechanism listed below is not a method by which enzymes form this transition
A: altering the shape of the enzyme to open up the active site and then the enzyme is
released with the changed conformation.
Which of the following does not affect membrane fluidity?
A: number of integral membrane proteins.
** Rate of reaction decreases once 40 degrees and enzyme becomes denatured,
decreasing enzyme function.
Feedback inhibition involves:
** Know the steps of allosteric regulation
The functions of proteins in a semi-permeable lipid bilayer are:
A: to aid in transport, recognition and attachment to other cells, and provide a semi-
permeable environment inside the bilayer.
A reaction at equilibrium will have:
A: highest entropy possible and rate of reverse…
Common factor between active transport and endo/exocytosis?
A: both use concentration gradients, and methods of transport across membrane, use ATP.
Which of the following is false about secondary transport?
a) Transport is indirectly driven by ATP hydrolysis.
b) Transport proteins break down the ATP.
c) Use concentration gradient.
d) All of the above.
What helps a cell survive and cope with high temperature?
a) Decreasing the amount of unsaturated fatty acid.
b) Presence of sterols, which bond to the hydrophilic heads of the lipid bilayer.
c) Increasing the amount of saturated fatty acids.
d) All of the above.
** Higher amount of solution= hypertonic.
Diffusion is driven by potential energy, which occurs because?
a) Electrical gradient.