Bio 103 Module 2 Test
During the citric acid cycle, each acetyl group entering the cycle yields
1 ATP, 3 NADH, and 1 FADH2.
Consider the following two chemical equations: A. glucose + fructose → sucrose + H2O, ΔG = +27 kJ/mole (or +6.5 kcal/mole) B. glucose + fructose + ATP → sucrose + ADP + Pi, ΔG = −5 kJ/mole (or −1.2 kcal/mole) What is the overall ΔG?
22 kJ/mole
What is calmodulin?
A calcium-binding protein
Peter Mitchell demonstrated ATP production by aerobic bacteria to prove what process?
Chemiosmosis
Which refers to an organic, non-polypeptide compound that binds to the apoenzyme and serves as a cofactor?
Coenzyme
Which is an example of a second messenger?
Cyclic AMP
In which of the following aerobic respiration stages does a chain of several electrons transport molecules and release energy to form a proton gradient?
Electron transport and chemiosmosis
Why type of energy is represented by a positive change in G?
Endergonic
What cellular process is represented in the accompanying figure?
Exocytosis
Which cellular mechanism ejects products, such as hormones, by the fusion of a vesicle with the plasma membrane?
Exocytosis
A(n) exergonic reaction results in a net gain of free energy.
False
An absorption spectrum indicates the relative effectiveness of different wavelengths of light in powering photosynthesis.
False
At a plant's light compensation point the rate of photosynthesis is greater than the rate of respiration.
False
Enzymes called proteases in the ER lumen catalyze folding of proteins into proper conformations.
False
In competitive inhibition, the inhibitor binds to the enzyme at the allosteric site.
False
In photosynthesis, the oxygen atoms released as O2 comes from CO2.
False
In the sodium-potassium pump, sodium ion release causes the carrier protein to return to its original shape and releases two K+ ions into the cell.
False
Insulin stimulates cells to take in glucose by facilitated diffusion, so the down regulation of insulin receptors increases the ability of cells to take in glucose. __________________
False
Mitochondria play an important role in cell necrosis.
False
In glycolysis, a phosphorylated sugar (fructose-1,6-bisphosphate) is split, forming two molecules of
G3P
Which type of electromagnetic waves has the shortest wavelength?
Gamma waves
What is the primary function of the leaf structure labeled as 5 in the accompanying figure?
Gas exchange
Select the phosphorylation reaction.
Glucose + ATP → glucose-P + ADP
Which of the following molecules can be used as a substrate for cellular respiration?
Glucose, lipids, proteins, and fatty acids
What color does chlorophyll reflect?
Green
What are the reactants of the light-dependent reactions of photosynthesis?
H2O, ADP, and NADP+
Which local regulator is stored in cells of the immune system and released during an allergic reaction?
Histamine
Consider the cellular process illustrated in the accompanying figure. What substance would most likely be transported in this manner?
Hormones
What type of protein can transduce a signal in two directions?
Integrins
A receptor on the cell surface usually has several domains. What is the function of the external domain?
It is the docking site for a signaling molecule.
As you climb a flight of stairs, what type of energy are your legs in motion using?
Kinetic energy
The main signaling cascade for cell division and differentiation is the ____ cascade.
MAP kinase
What type of chemical compound diffuses across synapses?
Neurotransmitters
Select the hydrogen acceptor molecule that stores electrons in the process of photosynthesis.
Nicotinamide adenine dinucleotide phosphate (NADP+)
What is the reaction in which a phosphate group is transferred from ATP to the sugar?
Phosphorylation
Which photosynthetic unit consists of a pair of chlorophyll a molecules with an absorption peak of 700 nm?
Photosystem I
Mammalian red blood cells contain which type of membrane?
Plasma membrane
Which statement about plasma membranes is false?
Plasma membranes prevent communication with other cells.
According to the graph in the accompanying figure, chlorophyll absorbs light most strongly in what region of the electromagnetic spectrum?
Red and blue wavelengths
What is the fluid-filled sac within the inner membrane of a chloroplast called?
Stroma
What is it called when a phosphate group is transferred to ADP from a phosphorylated intermediate?
Substrate-level phosphorylation
Which of the following steps in the citric acid cycle directly produces a molecule of ATP (or GTP)?
Succinyl CoA → succinate
How do the phospholipids in vegetable oil differ from those of animal fat?
The fatty acid tails bend.
Which of the following statements about the electron transport chain is true?
The proton gradient established during electron transport is a form of potential energy.
Although glucose molecules constantly diffuse into a red blood cell along their concentration gradient, equilibrium is never reached and a steep concentration gradient is continually maintained. What causes this?
The rapid addition of a phosphate to the glucose molecules
How is paracrine signaling different from other types of signaling?
The signaling molecules are diffused through interstitial fluid and act on nearby cells.
Mutations to ABC transporter genes contribute to cystic fibrosis.
True
The micrometer (μm) is the most convenient unit for measuring cells.
True
The product of the Calvin cycle that is of greatest practical importance to the plant is carbohydrate.
True
Which is a major group of enzyme-linked receptors?
Tyrosine kinases
The equation, G = H − TS, predicts that
as entropy increases, the amount of free energy decreases.
Because enzymes affect the speed of chemical reactions without being consumed, they are referred to as
catalysts.
Which cellular structure is correctly matched to the role it plays within the cell?
centrosome−cell division
Once ligand molecules bind to receptors in coated pits of a plasma membrane, the next step of receptor-mediated endocytosis would be
coated vesicle forms by endocytosis.
Amino acids are metabolized by reactions in which the amino group (2NH2) is first removed, this is known as ________.
deamination
In a reaction in which the rate of the reverse reaction is equal to the rate of the forward reaction, a state of ____ is attained.
dynamic equilibrium
Scaffold proteins ensure that signals are relayed ____.
efficiently
The outer membrane of the nuclear envelope is continuous with the membrane of the ____ and is usually covered with attached ribosomes.
endoplasmic reticulum
Suppose the free energy of the reactants is greater than the free energy of the products. Such a reaction is referred to as a(n) ____.
exergonic reaction
A basal body anchors what part of a cell?
flagellum
When an electron returns to its ground state, energy will be released as heat or as an emission of light, known as
fluorescence.
Which strategy is the most effective for larger cells to have an effective surface area to volume ratio?
having thin, finger-like projections
Intermediate filaments are most closely associated with which of the following?
keratins
Typically, the gate of an ion channel remains closed until a(n) ____ binds to the receptor.
ligand
An electron absorbs a photon of light energy and becomes energized; the electron shifts from a ____ atomic orbital to a __________ atomic orbital.
lower energy; higher energy
The ratio of the size of the image seen with the microscope to the actual size of the object is called:
magnification
Which one of these are the most convenient unit for measuring cells?
micrometer
Which of the following is a key component of the cytoskeleton?
microtubules
Which two organelles are responsible for converting energy into forms that can be used by cells?
mitochondria and chloroplasts
Choanoflagellates are important in the study of cell communication evolution because choanoflagellates have
protein kinases similar to those in animals.
The energy released during the chain of electron transport molecules is used to create a(n) ____ gradient across the inner mitochondrial membrane for chemiosmosis.
proton
The process of receiving an incoming signal is known as _______.
reception
The accompanying image is the product of which type of microscope?
scanning electron microscope
In order for a cell to maintain a high degree of order, it must constantly
use energy.
Upon observing a cell of a grass blade, you notice a prominent sac that occupies a large portion of the cell. Which organelle is this?
vacuole
LDL cholesterol is taken into the cell by receptor-mediated endocytosis.
True
Which of the following statements about phospholipids is false?
They contain three fatty acids chains.
Which of the following is not a property of membranes?
They inhibit the passage of materials.
Which of the following statements is contrary to the second law of thermodynamics?
Total entropy in the universe is decreasing with time.
A reversible inhibitor forms weak chemical bonds with the enzyme.
True