Which of the following is the simplest collection of matter that can live?
cell
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
-Although the resolution of the light microscope is far less than that of electron microscopes, light microscopy is the only technique that permits one to observe living cells.
Which of the following statements is true about cell fractionation?
Cell fractionation separates cells into their component parts
-The organelles are usually separated by centrifugation.
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
-The high surface area is likely to be associated with high transport rates of compounds across the plasma membrane. The greater the surface area, the greater the potential for trans
Which of the following is/are likely to limit the maximum size of a cell?
the cell's surface-to-volume ratio
the time it takes a molecule to diffuse across a cell
the shape of the cell
ANSWER: All of the choices are correct.
Which of the following structures is found in eukaryotic but NOT prokaryotic cells?
mitochondria
-Only eukaryotic cells have membrane-bound organelles such as mitochondria.
A substance moving from outside the cell into the cytoplasm must pass through __________.
the plasma membrane
-The plasma membrane defines the boundary between the cytoplasm and the outside of the cell.
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 presence of membrane-bounded organelles in eukaryotes permits cellular functions to occur in specialized, isolated compartments.
Bacterial cells are prokaryotic. Unlike a typical eukaryotic cell, they __________.
have no membrane-bounded organelles in their cytoplasm
-Prokaryotic cells have no membrane-bounded organelles.
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
-Some protists (such as algae) can photosynthesize, and so can plants. As both the protists and plants are eukaryotes, they contain organelles.
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.
-Proteins and ribosomal RNA are assembled into ribosomal subunits in the nucleolus.
Which of the following is FALSE in respect to eukaryotic chromosomes?
Chromosomes appear only as a cell is about to divide.
-This is false. Although chromosomes become more compact as a cell prepares to divide, they are always present in the cell.
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 radioact
the nucleus
-Large numbers of nucleotides would be used to make new DNA as the cells grew, and the DNA is housed in the nucleus.
Which of the following groups is primarily involved in synthesizing molecules needed by the cell?
ribosome, rough endoplasmic reticulum, smooth endoplasmic reticulum
-Each of these structures is capable of synthesizing molecules needed by cells.
Which of the following categories best describes the function of the rough endoplasmic reticulum?
manufacturing
-The rough endoplasmic reticulum is involved in the manufacture of proteins for the endomembrane system.
You would expect a cell with an extensive Golgi apparatus to __________.
secrete large amounts of protein
-The Golgi apparatus modifies and sorts the lipids and proteins produced in the ER. Cells that secrete large amounts of material require an extensive Golgi apparatus.
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
Golgi apparatus
-Vesicles carrying proteins from the rough ER fuse with the Golgi apparatus, where the proteins may be altered
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
-This is the only answer in which the protein is a membrane protein.
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
-Proteins of the endomembrane system are synthesized in the rough ER, modified and sorted in the Golgi, and then transported to other organelles of the endomembrane system such as vacuoles.
A protein that ultimately functions in the plasma membrane of a cell is most likely to have been synthesized __________.
in the rough endoplasmic reticulum
-All of the membrane proteins of the endomembrane systems are made in the rough ER.
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
-The mitochondria are not part of the endomembrane system and must synthesize their own lipids.
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
-Like the ribosomes in bacteria, the ribosomes in the mitochondria are smaller than those found free in the cytoplasm or bound to endoplasmic reticulum in the eukaryotes.
Which of the following statements about chloroplasts and mitochondria is true?
Chloroplasts and mitochondria synthesize some of their own proteins.
-Chloroplasts and mitochondria can synthesize some of their own proteins because they contain DNA and ribosomes.
Which type of cell is most likely to have the largest number of mitochondria?
muscle cells in the legs of a marathon runner
-Cellular respiration releases energy that cells need in order to carry out their functions. Active muscle cells need large amounts of energy.
Which of the following is FALSE?
Mitochondria contain ribosomes in the intermembrane space.
-The ribosomes in the mitochondria are found in the matrix of the mitochondria, not in the intermembrane space.
Which of the following organelles might be found inside other organelles?
ribosomes
-Ribosomes are nonmembranous organelles that are found in the cytoplasm but also in mitochondria and chloroplasts.
Microtubules and microfilaments commonly work with which of the following to perform many of their functions?
Golgi apparatus
-Microtubules guide vesicles from the ER to the Golgi and from the Golgi to the plasma membrane.
Which of the following structures is found in animal cells but NOT in plant cells?
centrioles
-Although plant cells have a microtubule organizing center, they lack a pair of centrioles.
Which statement about the cytoskeleton is true?
Components of the cytoskeleton often mediate the movement of organelles within the cytoplasm.
-The interaction of motor proteins with the cytoskeleton is responsible for the movement of organelles in cells.
Cilia and flagella move due to the interaction of the cytoskeleton with which of the following?
motor proteins
-Motor proteins, such as dynein, use energy to move parts of the cytoskeleton.
Basal bodies are most closely associated with which of the following cell components?
cilia
-The microtubule assembly of a cilium or flagellum is anchored in the cell by a basal body.
Dye injected into a plant cell might be able to enter an adjacent cell through __________.
plasmodesmata
-The cell walls of plant cells contain numerous channels, with strands of cytoplasm passing through them and connecting one cell's cytoplasm to that of an adjacent cell.
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 membranes of neighboring cells are actually fused at a tight junction, forming a seal that prevents the leakage of extracellular fluid across the layer of epithelial cells.
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.
-Both plant cell walls and the ECM of animal cells allow movement of water and small solutes.