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18 terms

AP Bio Test 1

Enzymes are biological catalysts that function by
a. increasing free energy in a system
b. lowering activation energy of a reaction
c. lowering entropy in a system
d. increasing temperature near a reaction
e. altering the equilibrium of the reaction
B. (lowering activation energy of a reaction)
Ascorbic acid, which is found in citrus fruits, acts as an inhibitor to catecholase, the enzyme responsible for the browning reaction in fruits such as apples. One explanation for the inhibiting function of this acid could be its similarity, in terms of size and shape, to catechol, the substrate of the browning reaction. If this explanation is correct, then this inhibition is most likely an example of ________ inhibition
a. competitive
b. indirect
c. noncompetitive
d. allosteric
e. feedback
a. (competive)
Ascorbic acid, which is found in citrus fruits, acts as an inhibitor to catecholase, the enzyme responsible for the browning reaction in fruits such as apples. Suppose studies indicate that ascorbic acid is not similar to catechol in size and shape and that the pH of the ascorbic acid solution alters the protein folding of the catecholase. If this is true, then this inhibition is most likely an example of
a. competitive inhibition
b. enzyme denaturation
c. noncompetitive inhibition
d. allosteric regulation
e. feedback inhibition
b. (enzyme denaturation)
Osmosis is
a. the movement of water across membranes
b. the active transport of water across membranes
c. unidirectional diffusion of water across membranes
d. unaffected by solute concentrations inside cells
e. a process that requires energy
a. (the movement of water across membranes)
What would happen if a suspension of red blood cells in an isotonic NaCl solution was suddenly diluted with pure water by a factor of 10?
a. Nothing would happen
b. the cells would lose water and shrink
c. The cells would swell and lyse (burst)
d. the cells would take up water, but the cell wall would prevent bursting
e. the cells would pump water out of the cell
c. (The cells would swell and lyse [burst])
In addition to the bilayer lipids and proteins, membranes may contain _______ in the form of ______ and ______.
a. nucleic acids; DNA; RNA
b. carbohydrates; cellulose; starch
c. triglycerides; fats; oils
d. nucleotides; ATP; GTP
e. carbohydrates; glycoproteins; glycolipids
e. (carbohydrates; glycoproteins; glycolipids)
In facilitated diffusion,
a. molecules may be transported against their concentration gradient
b. specific integral membrane proteins mediate transport
c. the rate of transport is independent of the concentration of the molecule transported
d. ATP is used
e. endocytosis is involved
b. (specific integral membrane proteins mediate transport)
All cellular membranes
a. regulate which materials can cross the membrane
b. support the cell and determine its shape
c. produce energy for the cell
d. produce proteins for the cell
e. move the cell
a. (regulate which materials can cross the membrane)
The plasma membrane of a cell
a. separates the cell from its environment
b. regulates what goes into and out of the cell
c. helps maintain a constant internal environment
d. communicates with adjacent cells
e. all of the above
e. (all of the above)
A prokaryotic cell does NOT have a ____ or ______.
a. nucleus; membrane-bound organelles
b. nucleus; DNA
c. nucleus; ribosomes
d. nucleus; membranes
e. cell wall; membranes
a. ( nucleus; membrane-bound organelles)
Ribosomes are made up of
a. DNA and RNA
b. DNA and proteins
c. RNA and proteins
d. proteins
e. DNA
C. (RNA and proteins)
The DNA of prokaryotic cells is found in the
a. plasma membrane
b. nucleus
c. ribosome
d. nucleoid region
e. mitochondria
d. (nucleoid region)
Which of the following statements about the nuclear envelope is true?
a. it contains pores for the passage of large particles
b. it is composed of two membranes
c. it contains ribosomes on the inner surface
d. both a and b
e. all of the above
d. (both a and b)
You would NOT expect to find RNA in which of the following structures?
a. nucleus
b. mitochondrion
c. vacuole
d. ribosome
e. prokaryotic cell
c. (vacuole)
Chromatin is a series of entangled threads composed of
a. microtubules
b. DNA and protein
c. fibrous proteins
d. cytoskeleton
e. membranes
b. (DNA and protein)
In the mitochondria, the energy from "food" molecules (such as glucose) that are partially broken down in the cytosol are converted to
a. ATP
b. CTP
c. GTP
d. TTP
e. UTP
a. (ATP)
Chloroplasts are the structures in which
a. chemical energy is stored in the form of ATP
b. cell division is controlled
c. genetic information is used to make proteins
d. sunlight energy is converted into chemical energy
e. new organelles are made
d. (sunlight energy is converted into chemical energy)
The cytoskeleton consists of
a. cilia, flagella, and microfilaments
b. cilia, microtubules, and microfilaments
c. internal cell walls
d. microtubules, intermediate filaments, and microfilaments
e. calcified microtubules
d. (microtubules, intermediate filaments, and microfilaments)