Which of the following is a correct description of the events of cellular respiration and teh sequence of events in cellular respiration?
oxidation of glucose to pyruvate; oxidation of pyruvate; oxidation of acetyl-CoA; oxidative phosphorylation
What environmental changes can affect the rate of an enzyme reaction?
pH; substrate concentration; heating or cooling of the enzyme
Fermentation is essentially glycolysis plus an extra step in which pyruvate is reduced from lactate or alcohol and carbon dioxide. This last step ______.
enables the cell to recycle the reduced NADH to oxidized NAD+
Is the following statement true or false: All cells have an equilibrium potential, a difference in electrical charges across their plasma membrane.
False, the difference in electrical charge is membrane potential.
Is the following statement about enzymes true or false: The action of competitive inhibitors may be reversible or irreversible.
In an experiment, mice were fed glucose (C6H12O6) containing a small amount of radioactive oxygen. The mice were closely monitored, and after a few minutes radioactive oxygen atoms showed up in _____.
Above a certain substrate concentration, the rate of an enzyme catalyzed reaction drops as the enzymes become saturated. What would lead to a faster conversation of substrate into product under these saturated conditions?
an increase in concentration of enzyme and/or an increase of temperature by a few degrees.
The formation of glucose-6-phosphate from glucose is an endergonic reaction and is couple to what reaction or pathway?
The hydrolysis of ATP
What process and organelle accounts for the replacement of lipids and proteins lost from the plasma membrane?
exocytosis and the smooth and rough ERs
Most cells cannot harness heat to perform work because?
temperature is usually uniform throughout the cell.
The energy given up by electrons as they move through the electron transport chain is used in what process?
pumping H+ across a membrane
What is the range of wavelengths of light that are absorbed by the pigments in the thylakoid membranes?
blue-violet and red-orange
If an enzyme is added to a solution where its substrate and product are in equilibrium, what will occur?
Nothing; the reaction will stay at equilibrium.
In brewing beer, malatose (a disaccharide of glucose) is ______.
the substrate for alcoholic fermentation
What kind of molecule would be least likely to diffuse through a plasma membrane without the help of a transport protein?
a large polar molecule
True or False: The sodium potassium pump hydrolyzes ATP and results in a net charge of +1 inside the cell.
The active site of an enzyme may resemble a groove or pocket in the surface of a protein into which the _______ fits.
What is an example of cellular work accomplished with the free energy derived from the hydrolysis of ATP, involved in the production of electrochemical gradients?
proton movement against a gradient of protons
Enzymes speed up the rate of the reaction without changing the ________ for the reaction.
DeltaG or Free Energy
What describes the electron transport chain?
Electrons are passed from one carrier to another releasing a little energy at each step.
In the overall process of glycolysis and cellular respiration, ______ is oxidized and _____ is reduced.
glucose is oxidized and oxygen is reduced
When one molecule is broken down into six component molecules, what will always be true?
DeltaS is positive.
Green olives may be preserved in brine, which is a 30% salt solution. How does this method of preservation prevent microorganisms from growing in the olives?
The 30% salt solution is hypertonic to the bacteria, so they lose too much water and plasmolyze
During the reaction C6H12O6 + 6 O2 = 6 CO2 + 6 H2O, which compound is reduced as a result of the reaction.
In the Calvin cycle, CO2 is combined with _______.
a 5-carbon compound to form an unstable 6-carbon compound, which decomposes into two 3-carbon compounds.
Consider the transport of protons and sucrose into a plant cell by the sucrose-proton cotransport protein. Plant cells continuously produce a proton gradient by using the energy of ATP hydrolysis to pump protons out fo the cell. Why, in the absence of sucrose, don't protons move back into the cell through the sucrose-proton cotransport protein?
The movement of protons through the cotransport protein cannot occur unless sucrose also moves at the same time.
_______, but not _______ can nourish themselves beginning with CO2 and other nutrients that are inorganic.
Why is no carbon dioxide produced during glycolysis?
The products of glycolysis contain the same total number of carbon atoms as in the starting material.
Metabolic pathways in cells are typically far from equilibrium. What processes tend to lead to keep these pathways away from equilibrium?
an input of free energy from the outside pathway and the continuous removal of the products of a pathway to be used in other reactions.
If a red blood cell and a plant blood cell were placed in seawater, what would happen to the two types of cells?
Both cells would lose water; the red blood cell would shrive, and the plant plasma membrane would pull away from the cell wall.
What is one of the roles of phospholipids in the structure and function of biological membranes?
Phospholipids form a selectively permeable structure.
What is a good description for heat as it relates to biological reactions?
An increase in heat increases the kinetic energy of the substrates and increases the rate of enzyme-catalyzed reactions
What cell structure exhibits selective permeability between a cell and its external environment?
the plasma membrane
What metabolic pathway is common to both fermentation and cellular respiration of a glucose molecule?
Which part of the catabolism of glucose by cellular respiration requires molecular oxygen (O2) and produces CO2?
a combination of the citric acid cycle and electron transport
During photosynthesis in chloroplasts, O2 is produced from _____ via a series of reactions associated with _______
H2O.... photosystem II
What is a function of membrane proteins that also facilitates tissue formation during embryogenesis?
Membrane proteins with short sugar chains form identification tags that are recognized by other cells.
What condition would tend to create greater membrane fluidity?
a greater portion of unsaturated phospholipids
Where to the reactions of the citric acid cycle occur in a eukaryotic cell?
the matrix of the mitochondrion
True or False: Enzymes can change the equilibrium point of reactions, but they cannot speed up reactions because they cannot change the net energy output.
Enzymes can lower the ____________ of reactions, but they cannot change the ______________.
activation energy ....... net energy output.
In general, the hydrolysis of ATP drives cellular work by _______.
releasing free energy that can be coupled to other reactions.
When a poison such as cyanide blocks the electron transport chain, glycolysis and the citric acid cycle also eventually stop working. Why?
NAD+ and FAD are not available for glycolysis and the citric acid cycle to continue.
What is the source of the energy that produces the chemiosmotic gradient in mitochondria?
electrons moving down the electron transport chain
When solid tumors of animals reach a certain size, the center of the tumor begins to die. To prevent this, the tumor can recruit new blood vessels. What purpose does the recruitment of blood vessels to growing tumors serve?
It supplies oxygen for aerobic cellular respiration and glucose to the rapidly dividing cells
The internal solute concentration of a plant cell is about 0.8 M. To demonstrate plasmolysis, it would be necessary to suspend the cell in what solution?
1.0 M or any solution that is hypertonic to the plant cell
The plasma membrane is referred to as the "fluid mosaic" structure. What do the words "fluid" and "mosaic" refer to?
The fluid aspect of the membrane is due to the lateral and rotational movement of the phospholipids, and the embedded proteins account for the mosaic aspect.
Passive transport permits the solute to move in either direction, but the net movement of the population of the solute occurs ________ of the molecule.
down the concentration gradient
The energy used to produce ATP in the light reactions of photosynthesis comes from _______.
The movement of H+ through a membrane
How is photosynthesis similar in C4 plants and CAM plants?
In both cases, rubisco is not used to fix carbon initially.
What accompanies the conversion of pyruvate to acetyl CoA before the citric acid cycle?
The release of CO2 and the synthesis of NADH
During aerobic respiration, molecular oxygen (O2) is used for what purpose?
at the end of the electron transport chain to accept electrons and form water
What is the role of NADP+ in photosynthesis?
It is reduced and then carries electrons to the Calvin cycle
The concentration of solutes in a red blood cell is about 2%, but red blood cells contain almost no sucrose or urea. Sucrose cannot pass through the membrane, but water and urea can. Osmosis would cause red blood cells to shrink the most when immersed in what kind of a sucrose solution?
a hypertonic solution
During respiration in the eukaryotic cells, the electron transport chain is located in or on the ______.
inner membrane of the mitochondrion
Where in the plasma membrane would cholesterol most likely be found?
in the interior of the membrane
What is the difference between active transport and facilitated diffusion?
Active transport requires energy from ATP, and facilitated diffusion does not.
During photosynthesis in a eukaryotic cell, an electrochemical gradient is formed across the _______.
Where, relative to the cell, is the concentration of potassium much higher than the concentration of sodium while the cell is at resting potential?
Inside the cell
When is the asymmetrical distribution of membrane proteins, lipids, and carbohydrates across the plasma membrane determined?
as the membrane is being constructed
If muscle cells in the human body consume O2 faster than it can be supplied what is likely to result?
The muscle cells will have trouble making enough ATP, will not be able to carry out oxidative phosphorylation, and will consume glucose at an increased rate
What is the function of carbohydrates associated with the plasma membrane?
Membrane carbohydrates function primarily in cell-cell recognition.
What do the sign and magnitude of the DeltaG of a reaction tell us about the speed of the reaction?
Neither the sign or the magnitude of DeltaG have anything to do with the speed of the reaction. The speed of the reaction is determined by the activation energy barrier of the reaction and the temperature.