Practice Test Flashcards
Which of the following is the simplest collection of matter that can live?
A researcher wants to film the movement of chromosomes during cell division. Which type of microscope should she choose and why is it the best choice?
light microscope, because the specimen is alive
Which of the following statements is true about cell fractionation?
Cell fractionation separates cells into their component parts.
Consider two cells with the same volume but with very different surface areas due to differences in their shapes. The cell with the larger surface area is likely to __________.
be involved in the rapid uptake of compounds from the cell's environment
Which of the following is/are likely to limit the maximum size of a cell?
the cell's surface-to-volume ratio; the shape of the cell; the time it takes a molecule to diffuse across a cell
Which of the following structures is found in eukaryotic but NOT prokaryotic cells?
A substance moving from outside the cell into the cytoplasm must pass through __________.
the plasma membrane
In terms of cellular function, what is the most important difference between prokaryotic and eukaryotic cells?
Eukaryotic cells are compartmentalized, which allows for specialization.
Bacterial cells are prokaryotic. Unlike a typical eukaryotic cell, they __________.
have no membrane-bounded organelles in their cytoplasm
Which of the following features do prokaryotes and eukaryotes have in common?
ribosomes, plasma membrane, and cytoplasm
A particular cell has a nucleus and chloroplasts in addition to the fundamental structures required by all cells. Based on this information, this cell could be __________.
a photosynthetic protist cell or a plant cell
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 the following is FALSE in respect to eukaryotic chromosomes?
Chromosomes appear only as a cell is about to divide.
A dish of animal cells was grown in the presence of radioactive phosphorous. The phosphorous largely ended up in nucleotides inside the actively growing animal cells. In which cellular structure or structures would you predict the majority of the radioactive phosphorous to accumulate?
Which of the following groups is primarily involved in synthesizing molecules needed by the cell?
ribosome, rough endoplasmic reticulum, smooth endoplasmic reticulum
Which of the following organelles is UNLIKELY to show enhanced abundance in pancreatic cells that secrete large amounts of digestive enzymes?
free cytoplasmic ribosomes
Which of the following categories best describes the function of the rough endoplasmic reticulum?
You would expect a cell with an extensive Golgi apparatus to __________.
secrete large amounts of protein
A researcher made an interesting observation about a protein made by the rough endoplasmic reticulum and eventually found in a cell's plasma membrane. The protein in the plasma membrane was actually slightly different from the protein made in the ER. The protein was probably altered in the __________.
Consider a protein that is made in the rough endoplasmic reticulum. You observe that when the synthesis of the protein is completed, the protein is located in the ER membrane. Where else in the cell might this protein be found?
embedded in the plasma membrane, functioning in the transport of molecules into the cell
Which of the following sequences represents the order in which a protein made in the rough endoplasmic reticulum might move through the endomembrane system?
Golgi apparatus → lysosome
A protein that ultimately functions in the plasma membrane of a cell is most likely to have been synthesized __________.
in the rough endoplasmic reticulum
Which of the following five membranes is most likely to have a lipid composition that is distinct from those of the other four?
mitochondrial outer membrane
Chloroplasts and mitochondria are thought to be of prokaryotic origin. One piece of evidence that supports this hypothesis is that these organelles contain prokaryotic-like ribosomes. These ribosomes are probably most similar to ribosomes found __________.
in bacterial cells
Which of the following statements about chloroplasts and mitochondria is true?
Chloroplasts and mitochondria synthesize some of their own proteins.
Which type of cell is most likely to have the largest number of mitochondria?
muscle cells in the legs of a marathon runner
Which of the following is FALSE?
Mitochondria contain ribosomes in the intermembrane space.
Which of the following organelles might be found inside other organelles?
Microtubules and microfilaments commonly work with which of the following to perform many of their functions?
Which of the following structures is found in animal cells but NOT in plant cells?
Which statement about the cytoskeleton is true?
Components of the cytoskeleton often mediate the movement of organelles within the cytoplasm.
Cilia and flagella move due to the interaction of the cytoskeleton with which of the following?
Basal bodies are most closely associated with which of the following cell components?
Dye injected into a plant cell might be able to enter an adjacent cell through __________.
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.
Which of the following statements correctly describes a common characteristic of a plant cell wall and an animal cell extracellular matrix?
Both are permeable to water and small solutes.
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.
The plasma membrane is referred to as a "fluid mosaic" structure. Which of the following statements about that model is true?
The fluid aspect of the membrane is due to the lateral and rotational movement of phospholipids, and embedded proteins account for the mosaic aspect.
Consider the currently accepted fluid mosaic model of the plasma membrane. Where in the plasma membrane would cholesterol most likely be found?
in the interior of the membrane
Which of the following is NOT a function of membrane proteins?
energy, carbon, and nitrogen storage
Which of the following functions of membrane proteins is important in tissue formation during embryonic development in animals?
Membrane proteins with short sugar chains form identification tags that are recognized by other cells.
Which of the following statements concerning carbohydrates associated with the plasma membrane is correct?
Membrane carbohydrates function primarily in cell-cell recognition.
Consider the currently accepted fluid mosaic model of the plasma membrane. Where in the membrane would carbohydrates most likely be found?
on the outside (external) surface of the membrane
Which statements about the sidedness of the plasma membrane is correct?
Parts of proteins that are exposed on the cytoplasmic side of the endoplasmic reticulum are also exposed on the cytoplasmic side of the plasma membrane.
The two lipid layers may differ in specific lipid composition.
Every integral membrane protein has a specific orientation in the plasma membrane.
The asymmetrical distribution of membrane proteins, lipids, and carbohydrates across the plasma membrane is determined as the membrane is being constructed.
Which of the following molecules is most likely to passively diffuse across the plasma membrane?
Which of the following would be LEAST likely to diffuse through a plasma membrane without the help of a transport protein? (
a large, polar molecule
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 solute molecules occurs down the concentration gradient of the molecule.
Cells A and B are the same size, shape, and temperature, but cell A is metabolically less active than cell B. and 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
Which of the following statements about diffusion is true?
It is a passive process.
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?
Question 15:A single plant cell is placed in an isotonic solution. Salt is then added to the solution. Which of the following would occur as a result of the salt addition?
Water would leave the cell by osmosis, causing the volume of the cytoplasm to decrease.
Seawater is hypertonic to cytoplasm in vertebrate cells and in plant cells. 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.
Which of these statements describes some aspect of facilitated diffusion?
Facilitated diffusion of solutes may occur through channel or transport proteins in the membrane.
Which of the following is FALSE in regard to facilitated diffusion?
Facilitated diffusion requires the hydrolysis of ATP.
A selectively permeable membrane separates two solutions. Water is able to pass through this membrane; however, sucrose (a disaccharide) and glucose (a monosaccharide) cannot pass. The membrane separates a 0.2-molar sucrose solution from a 0.2-molar glucose solution. With time, how will the solutions change?
Nothing will happen, because the two solutions are isotonic to one another.
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 which of the following solutions?
a hypertonic sucrose solution
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?
A 30% salt solution is hypertonic to the bacteria, so they lose too much water and undergo plasmolysis.
Active transport requires an input of energy and can also generate voltages across membranes. Based on this information, which of the following statements is true?
The sodium-potassium pump hydrolyzes ATP and results in a net positive change outside the cell membrane.
Glucose can be moved into cells via an active transport mechanism when the concentration of glucose inside the cell is higher than the concentration of glucose outside of the cell. This active transport mechanism moves glucose and sodium into the cell at the same time. The glucose moves up its gradient and the sodium moves down its gradient. Which of the following statements about this mechanism is accurate?
To pump glucose up its concentration gradient, sodium moves down its concentration gradient, and the distribution of sodium ions across the membrane forms an electrochemical gradient that drives this mechanism.
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.
A cell has a membrane potential of –100 mV (more negative inside than outside) and has 1,000 times more calcium ions outside the cell than inside. Which of the following best describes a mechanism by which Ca2+ enters the cell?
facilitated diffusion of Ca2+ into the cell down its electrochemical gradient
Which of the following correctly describes a general property of all electrogenic pumps?
Electrogenic pumps create a voltage difference across the membrane.
Which of the following statements about cotransport of solutes across a membrane is correct?
Cotransport proteins allow a single ATP-powered pump to drive the active transport of many different solutes.
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 of the cell. Why, in the absence of sucrose, do protons not move back into the cell through the sucrose-proton cotransport protein?
The movement of protons through the cotransport protein cannot occur unless sucrose moves at the same time.
Which of the following enables a cell to pick up and concentrate a specific kind of molecule?
Which of the following processes and organelles account for the replacement of lipids and proteins lost from the plasma membrane?
exocytosis and smooth ER and rough ER
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?
Which of the following pairs correctly matches a membrane transport process to its primary function?
pinocytosis: the uptake of water and small solutes into the cell by formation of vesicles at the plasma membrane