Bio 1 - Chapters 6-9 Study Modules
The internal solute concentration of a plant cell is about 0.8M. To demonstrate plasmolysis, it would be necessary to suspend the cell in what solution?
1.0 M
Which of the following plant cells would exhibit the most turgor pressure?
A cell placed in a hypotonic solution
The extracellular matrix of the animal cell has all of the following molecular components except __________.
A middle lamella
All of the processes involved in cellular respiration produce ATP. Which of the following processes produces the most ATP?
Oxidative phosphorylation
Which of the following statements about passive transport is correct?
Passive transport permits the solute to move in either direction, but the net movement of the population of solute molecules occurs down the concentration gradient of the molecule.
Which of the following molecules are most abundant in the plasma membrane?
Phospholipids
Which of the following statements about the role of phospholipids in the structure and function of biological membranes is correct?
Phospholipids form a selectively permeable structure.
Dye injected into a plant cell might be able to enter an adjacent cell through __________.
Plasmodesmata
Cell junctions in plant cells are called __________, and communicating junctions in animal cells are called __________.
Plasmodesmata, gap junctions
What would the value of ΔS be for a chemical reaction in which a molecule is broken down into smaller components?
Positive
How does the "fluid mosaic model" describe the structure of the plasma membrane?
Proteins in the membrane contribute to the mosaic quality of the membrane while the lateral and rotational movements of phospholipids contribute to its fluidity.
Which of the following statements is correct regarding ATP?
The energy in an ATP molecule is released through hydrolysis of one of the phosphate groups.
At low pH, a particular enzyme catalyzes a reaction at a high rate. At neutral pH, the enzyme is completely inactive. What statement best explains the difference in how pH affects the function of this enzyme?
The enzyme is adapted for low pH but is denatured at neutral pH, leaving it nonfunctional.
The process of stabilizing the structure of an enzyme in its active form by the binding of a molecule is an example of __________.
allosteric regulation
Animal cells have unique organelles called __________ that are composed of structures called __________.
centrosomes; centrioles
Bacterial cells are prokaryotic. Unlike a typical eukaryotic cell they __________.
have no membrane-bounded organelles in their cytoplasm
Enzyme activity is affected by pH because __________.
high or low pH may disrupt hydrogen bonding or ionic interactions and thus change the shape of the active site
The walls of plant cells are largely composed of polysaccharides and proteins that are synthesized __________.
in the rough endoplasmic reticulum and in the Golgi apparatus
All cells have voltages across their membranes. This voltage is called a(n) __________ and is often maintained by __________.
membrane potential; electrogenic pumps
Microfilaments function in cell motility including __________.
muscle contraction, amoeboid movement, and cytoplasmic streaming in plants
The endoplasmic reticulum is part of the endomembrane system, which also includes the __________.
nuclear envelope, the Golgi apparatus, lysosomes, and vesicles
Evidence that supports the prokaryotic origins of mitochondria and chloroplasts are all of the following except __________.
that mitochondria and chloroplasts have multiple copies of linear DNA molecules associated with their inner membranes
Which of the following substances would be most likely to pass through the plasma membrane without the help of a transport protein?
A nonpolar molecule, such as a hydrocarbon
As ATP begins to build up in a cell, metabolism slows down. How does this happen?
ATP acts as an allosteric inhibitor to many of the enzymes involved in metabolism, thus slowing their function.
Which of the following is a correct difference between active transport and facilitated diffusion?
Active transport requires energy from ATP, and facilitated diffusion does not.
Which of the following correctly states the relationship between anabolic and catabolic pathways?
Anabolic pathways synthesize more complex organic molecules using the energy derived from catabolic pathways.
How does cholesterol affect membrane fluidity?
At body temperature, it makes the membrane less fluid
At low temperatures, a particular enzyme catalyzes a reaction, but at a slow rate. At high temperatures, the enzyme is completely inactive. What statement best explains the difference in how temperature affects the function of this enzyme?
At low temperatures, there is not enough free energy for the enzyme to function at a high rate, and at high temperatures, the enzyme is denatured, leaving it nonfunctional.
During aerobic respiration, molecular oxygen (O2) is used for which of the following purposes?
At the end of the electron transport chain to accept electrons and form H2O
Cells A and B are the same size, shape, and temperature, but cell A is metabolically less active than cell B; cell B is actively converting oxygen to water in cellular respiration. Oxygen will diffuse more rapidly into cell __________ because __________.
B; the diffusion gradient in cell B is steeper
Why is energy required for active transport?
Because it moves solutes against their concentration gradient
Which of the following statements correctly describes cofactors and coenzymes?
Both are nonprotein enzyme helpers; but most cofactors are metal ions, and coenzymes are organic molecules that are a specific type of cofactor.
If a red blood cell and a plant cell were placed in seawater, what would happen to the two types of cells?
Both cells would lose water; the red blood cell would shrivel, and the plant plasma membrane would pull away from the cell wall.
How does ATP drive mechanical work inside a cell?
By binding to motor proteins
How does ATP drive transport work inside a cell?
By phosphorylating a transport protein
Which of the following molecules is most likely to passively diffuse across the plasma membrane?
Carbon Dioxide
What function do carbohydrates fulfill in the plasma membrane?
Cell-to-cell recognition
The organelle that is a plant cell's compartment for the storage of inorganic ions such as potassium and chloride is the __________.
Central Vacuole
In facilitated diffusion, __________ proteins provide openings in the plasma membrane for substances to flow through without changing structure, and __________ proteins allow passage of substances through the plasma membrane after undergoing a subtle change in shape.
Channel; carrier
Which of the following is false in respect to cells' chromosomes?
Chromosomes are only visible as a cell is about to divide.
Basal bodies are most closely associated with which of the following cell components?
Cilla
Which of the following pairs of pathways and their location in the cell is incorrectly matched?
Citric acid cycle: cytosol
Which of the following statements is correct regarding competitive and noncompetitive enzyme inhibitors?
Competitive inhibitors bind to the active site of an enzyme while noncompetitive inhibitors bind to an enzyme away from the active site
Which statement about the cytoskeleton is true?
Components of the cytoskeleton often mediate the movement of organelles within the cytoplasm.
A nursing infant is able to obtain disease-fighting antibodies, which are large protein molecules, from its mother's milk. These molecules probably enter the cells lining the baby's digestive tract via which process?
Endocytosis
Which of the following states the relevance of the first law of thermodynamics to biology?
Energy can be freely transformed among different forms as long as the total energy is conserved.
If the entropy of a living organism is decreasing, which of the following is most likely to be occurring simultaneously?
Energy input into the organism must be occurring to drive the decrease in entropy.
Which of the following statements about enzyme function is correct?
Enzymes can lower the activation energy of reactions, but they cannot change the equilibrium point because they cannot change the net energy output.
Which of the following statements about enzymes is true?
Enzymes speed up the rate of the reaction without changing the ΔG for the reaction
In terms of cellular function, what is the most important difference between prokaryotic and eukaryotic cells?
Eukaryotic cells are compartmentalized, which allows for specialization.
The primary manner in which cells manage their energy resources in order to do work is called energy coupling. Which of the following statements accurately defines energy coupling?
Exergonic reactions drive endergonic reactions.
Which of the following processes and organelle(s) accounts for the replacement of lipids and proteins lost from the plasma membrane?
Exocytosis and E.R. (both smooth and rough)
Which of these statements describes some aspect of facilitated diffusion?
Facilitated diffusion of solutes may occur through channel or transport proteins in the membrane.
Cells must regulate their metabolic pathways so that they do not waste resources. What is the most common mechanism that regulates cellular respiration in most cells?
Feedback inhibition of glycolysis
Fermentation by itself produces no ATP but keeps glycolysis going, which produces a small amount of ATP. How does fermentation do this?
Fermentation oxidizes NADH to NAD+, which facilitates the production of ATP in glycolysis.
Which of the following reactions would be endergonic?
Glucose + fructose → sucrose
Which metabolic pathway is common to both fermentation and cellular respiration of a glucose molecule?
Glycolysis
Most of the ATP in cellular respiration is produced by the process of chemiosmosis. How does this process produce ATP?
H+ flows across the inner mitochondrial membrane through the enzyme ATP synthase
Observing a fluorescent micrograph cell with intermediate filaments would help you identify the cell as a __________.
Human skin cell
A protein that ultimately functions in the plasma membrane of a cell is most likely to have been synthesized __________.
In the rough E.R.
The network of fibers that organizes structures and activities in a cell __________.
Is the cytoskeleton
Which of the following statements about diffusion is true?
It is a passive process.
What is the role of oxygen in the electron transport chain?
It is reduced to form water.
Which of the following statements concerning carbohydrates associated with the plasma membrane is correct?
Membrane carbohydrates function primarily in cell-cell recognition.
Which of the following is true regarding metabolic pathways?
Metabolic pathways consist of a series of reactions, each catalyzed by a different enzyme.
After completion of the citric acid cycle, most of the usable energy from the original glucose molecule is in the form of __________.
NADH
During the energy payoff phase of glycolysis, __________.
NADH and ATP are produced
In what molecule(s) is the majority of the chemical energy from pyruvate transferred during the citric acid cycle?
NADH and FADH2
The region of a bacterial cell that contains the genetic material is called the __________.
Nucleoid
Which of the following is a correct description of the events of cellular respiration and the sequence of events in cellular respiration?
Oxidation of glucose to pyruvate; oxidation of pyruvate; oxidation of acetyl-coA; oxidative phosphorylation
In preparing pyruvate to enter the citric acid cycle, which of the following steps occurs?
Pyruvate is oxidized and decarboxylated, and the removed electrons are used to reduce an NAD+ to an NADH.
Most of the electrons removed from glucose by cellular respiration are used for which of the following processes?
Reducing NAD+ to NADH in glycolysis and the citric acid cycle AND producing a proton gradient for ATP synthesis in the mitochondria.
Which of the following groups is primarily involved in synthesizing molecules needed by the cell?
Ribosomes, E.R. (both rough and smooth)
You would expect a cell with an extensive Golgi apparatus to __________.
Secrete a lot of protein
What is the functional connection between the nucleolus, nuclear pores, and the nuclear membrane?
Subunits of ribosomes are assembled in the nucleolus and pass through the nuclear membrane via the nuclear pores.
Which of these statements about enzyme inhibitors is true?
The action of inhibitors may be reversible or irreversible.
Which of the following is changed by the presence of an enzyme in a reaction?
The activation energy
Red blood cells contain approximately a 2% concentration of solutes. A red blood cell is placed into a solution that contains a 4% concentration of solutes to which the cell is not permeable. What will happen to the red blood cell?
The cell wall decrease in size as water flows out of it
Most of the NADH that delivers electrons to the electron transport chain comes from which of the following processes?
The citric acid cycle
Which of the following metabolic pathways produce(s) the most ATP, per glucose molecule metabolized, during cellular respiration?
The electron transport chain and oxidative phosphorylation
What best characterizes the role of ATP in cellular metabolism?
The free energy released by ATP hydrolysis that may be coupled to an endergonic process via the formation of a phosphorylated intermediate.
Your intestine is lined with individual cells. No fluids leak between these cells from the gut into your body. Why?
The intestinal cells are bound together by tight junctions.
The energy from the electrons in NADH and FADH2 fuel what process in the electron transport chain?
The pumping of H+ across the cristae of the mitochondrion
A cell is placed into a solution and the cell shrinks. Which of the following is true regarding the solution?
The solution is hypertonic
Which of the following is correct regarding peripheral proteins?
These proteins are found only on the surface of the plasma membrane.
Which of the following is correct regarding integral proteins?
These proteins exhibit both hydrophilic and hydrophobic properties.
A small amount of ATP is made in glycolysis by which of the following processes?
Transfer of a phosphate group from a fragment of glucose to ADP by substrate-level phosphorylation
Fermentation is essentially glycolysis plus an extra step in which pyruvate is reduced to form lactate or alcohol and carbon dioxide. This last step __________.
enables the cell to recycle the reduced NADH to oxidized NAD+
The function of cellular respiration is to __________.
extract usable energy from glucose
ATP allosterically inhibits enzymes in ATP-producing pathways. The result of this is called __________.
feedback inhibition
During the energy investment phase of glycolysis, __________.
glucose is phosphorylated before it is split into two three-carbon molecules
In the overall process of glycolysis and cellular respiration, __________ is oxidized and __________ is reduced.
glucose; oxygen
Cells are small because __________.
of the geometric relationships between surface and volume
Which of the following structural arrangements of the components in biological membranes facilitates the cell membrane's property of selective permeability?
proteins embedded into two layers of phoshpolipids
Muscle tissues make lactate from pyruvate to do which of the following?
regenerate NAD+
An exergonic (spontaneous) reaction is a chemical reaction that __________.
releases energy when proceeding in the forward direction
In general, the hydrolysis of ATP drives cellular work by __________.
releasing free energy that can be coupled to other reactions
Cell motility, which includes changes both in cell location and in the movement of cell parts, requires interactions of the cytoskeleton __________.
with motor proteins
