Tamu Bio 111 Exam 2 review

When biologists wish to study the internal ultrastructure of cells, they can achieve the finest resolution by using

a transmission electronic microscope

The advantage of light microscopy over electron microscopy is that

light microscopy allows one to view dynamic processes in living cells

A primary objective of cell fractionation is to

separate the major organelles so that their particular functions can be determined

In the fractionation of homogenized cells using centrifugation, the primary factor that determines whether a specific cellular component ends up in the supernatant or the pellet is

the size and weight of the component.

Which of the following correctly lists the order in which cellular components will be found in the pellet when homogenized cells are treated with increasingly rapid spins in a centrifuge?

nucleus, mitochondria, ribosomes

Green fluorescent protein (GFP) can be used to fluorescently label a specific protein in cells by genetically engineering cells to synthesize the target protein fused to GFP. What is the advantage of using GFP fusions to visualize specific proteins, instead of staining cells with fluorescently labeled probes that bind to the target protein?

GFP fusions enable one to track changes in the location of the protein in living cells; staining usually requires preserved cells

What is the reason that a modern electron microscope (TEM) can resolve biological images to the subnanometer level, as opposed to tens of nanometers achievable for the best super-resolution light microscope?

Electron beams have much shorter wavelengths than visible light

What technique would be most appropriate to use to observe the movements of condensed chromosomes during cell division

light microscopy

All of the following are part of a prokaryotic cell except

an endoplasmic reticulum

The volume enclosed by the plasma membrane of plant cells is often much larger than the corresponding volume in animal cells. The most reasonable explanation for this observation is that

plant cells contain a large vacuole that reduces the volume of the cytoplasm

A mycoplasma is an organism with a diameter between 0.1 and 1.0 µm. What does the organism's size tell you about how it might be classified?

It could be a very small bacterium.

Which of the following is a major cause of the size limits for certain types of cells?

the need for a surface area of sufficient area to support the cell's metabolic needs

Which of the following statements concerning bacteria and archaea cells is correct?

Archaea cells contain small membrane-enclosed organelles; bacteria do not

The evolution of eukaryotic cells most likely involved

endosymbiosis of an aerobic bacterium in a larger host cell-the endosymbiont evolved into mitochondria

Prokaryotes are classified as belonging to two different domains. What are the domains?

Bacteria and Archaea

If radioactive deoxythymidine triphosphate (dTTP) is added to a culture of rapidly growing bacterialcells, where in the cell would you expect to find the greatest concentration of radioactivity?

nucleoid

Which organelle or structure is absent in plant cells?

centrosomes

Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules

proteins

The nuclear lamina is an array of filaments on the inner side of the nuclear membrane. If a method were found that could cause the lamina to fall into disarray, what would you expect to be the most likely consequence?

a change in the shape of the nucleus

Recent evidence shows that when chromosomes decondense during interphase, their DNA molecules do not intermingle. Instead, they occupy distinct territories within the nucleus. Considering the structure and location of the following structures, which is most likely to be involved in chromosomelocation?

the nuclear matrix

A cell with a predominance of free ribosomes is most likely

producing primarily cytoplasmic proteins

Which type of organelle or structure is primarily involved in the synthesis of oils, phospholipids, andsteroids?

smooth endoplasmic reticulum

Which structure is the site of the synthesis of proteins that may be exported from the cell?

rough ER

The Golgi apparatus has a polarity or sidedness to its structure and function. Which of the following statements correctly describes this polarity?

All of the above correctly describe polar characteristics of the Golgi function

The fact that the outer membrane of the nuclear envelope has bound ribosomes allows one to most reliably conclude that

at least some of the proteins that function in the nuclear envelope are made by the ribosomes on the nuclear envelope

The difference in lipid and protein composition between the membranes of the endomembrane system is largely determined by

the function of the Golgi apparatus in sorting and directing membrane components

Hydrolytic enzymes must be segregated and packaged to prevent general destruction of cellular components. Which of the following organelles contains these hydrolytic enzymes in animal cells

lysosome

Which of the following statements correctly describes some aspect of protein secretion from prokaryotic cells

Proteins that are secreted by prokaryotes are synthesized on ribosomes that are bound to the cytoplasmic surface of the plasma membrane

Tay-Sachs disease is a human genetic abnormality that results in cells accumulating and becoming clogged with very large and complex lipids. Which cellular organelle must be involved in this condition?

the lysosome

The liver is involved in detoxification of many poisons and drugs. Which of the following structures is primarily involved in this process and therefore abundant in liver cells?

smooth ER

Which of the following produces and modifies polysaccharides that will be secreted?

Golgi apparatus

Which of the following contains hydrolytic enzymes?

lysosome

Which organelle often takes up much of the volume of a plant cell?

vacuole

Which organelle is the primary site of ATP synthesis in eukaryotic cells?

mitochondrion

Which plant cell organelle contains its own DNA and ribosomes?

mitochondrion

Which animal cell organelle contains enzymes that transfer hydrogen from various substrates to oxygen?

peroxisome

Thylakoids, DNA, and ribosomes are all components found in

chloroplasts.

In a plant cell, DNA may be found

in the nucleus, mitochondria, and chloroplasts

The chemical reactions involved in respiration are virtually identical between prokaryotic and eukaryotic cells. In eukaryotic cells, ATP is synthesized primarily on the inner membrane of the mitochondria. In light of the endosymbiont theory for the evolutionary origin of mitochondria, where is most ATP synthesis likely to occur in prokaryotic cells?

on the plasma membrane

One of the key innovations in the evolution of eukaryotes from a prokaryotic ancestor is the endomembrane system. What eukaryotic organelles or features might have evolved as a part of, or as an elaboration of, the endomembrane system?

nuclear envelope

A cell has the following molecules and structures: enzymes, DNA, ribosomes, plasma membrane, and mitochondria. It could be a cell from

nearly any eukaryotic organism

Which type of organelle is found in plant cells but not in animal cells?

plastids

Why isn't the mitochondrion classified as part of the endomembrane system?

Its structure is not derived from the ER or Golgi

In a liver cell detoxifying alcohol and some other poisons, the enzymes of the peroxisome remove hydrogen from these molecules and

transfer the hydrogen to oxygen molecules to generate hydrogen peroxide

How does the cell multiply its peroxisomes

They split in two after they become sufficiently large

Motor proteins provide for molecular motion in cells by interacting with what types of cellular structures?

cytoskeletal structures

Movement of vesicles within the cell depends on what cellular structures?

microtubules and motor proteins

The smallest cell structure that would most likely be visible with a standard (not super-resolution) research-grade light microscope is

a mitochondrion

Which of the following contain the 9 + 2 arrangement of microtubules, consisting of nine doublets of microtubules surrounding a pair of single microtubules?

both flagella and motile cilia

Vinblastine, a drug that inhibits microtubule polymerization, is used to treat some forms of cancer. Cancer cells given vinblastine would be unable to

separate chromosomes during cell division

The differences among the three categories of cytoskeletal elements outlined in the table above would suggest that each of the following has specialized roles. Which of the following is a correct match? (All three elements are involved in the maintenance of cell shape.)

microtubules and chromosome movement

Centrioles, cilia, flagella, and basal bodies have remarkably similar structural elements and arrangements. Which of the following hypotheses is most plausible in light of such structural similarities?

Cilia and flagella arise from the centrioles

If an individual has abnormal microtubules, due to a hereditary condition, in which organs or tissues would you expect dysfunction?

sperm, larynx, and trachea: cells and tissues that contain flagella or cilia

Cytochalasin D is a drug that prevents actin polymerization. A cell treated with cytochalasin D will still be able to

move vesicles around the cell

Which of the following statements about the cytoskeleton is true?

Movement of cilia and flagella is the result of motor proteins causing microtubules to move relative to each other

Cells require which of the following to form cilia or flagella?

centrosomes

All of the following serve an important role in determining or maintaining the structure of plant cells. Which of the following are distinct from the others in their composition?

plant cell walls

What do the cell walls of plants and the extracellular matrix of animal cells have in common?

They have functional connections with the cytoskeleton inside the cell

The cell walls of bacteria, fungi, and plant cells and the extracellular matrix of animal cells are all external to the plasma membrane. Which of the following is a characteristic common to all of these extracellular structures?

They are constructed of polymers that are synthesized in the cytoplasm and then transported out of the cell.

When a potassium ion (K+) moves from the soil into the vacuole of a cell on the surface of a root, it must pass through several cellular structures. Which of the following correctly describes the order in which these structures will be encountered by the ion?

primary cell wall → plasma membrane → cytoplasm → vacuole

A mutation that disrupts the ability of an animal cell to add polysaccharide modifications to proteins would most likely cause defects in its

Golgi apparatus and extracellular matrix

The extracellular matrix is thought to participate in the regulation of animal cell behavior by communicating information from the outside to the inside of the cell via which of the following?

integrins

Plasmodesmata in plant cells are most similar in function to which of the following structures in animal cells?

gap junctions

Ions can travel directly from the cytoplasm of one animal cell to the cytoplasm of an adjacent cell through

gap junctions

Which of the following makes it necessary for animal cells, although they have no cell walls, to haveintercellular junctions

Maintenance of tissue integrity and barriers to fluid leakage requires cells to adhere tightly to one another

Recent evidence shows that signals from the extracellular matrix (ECM) can regulate the expression of genes in the cell nucleus. A likely mechanism is that

mechanical signals of the ECM can alter the cytoskeleton, which can alter intracellular signaling

Signals between the ECM and the cytoskeleton may be transmitted by

integrins

ECM proteins are made by ribosomes in which part of a eukaryotic cell?

rough ER

What types of proteins are not synthesized in the rough ER?

mitochondrial proteins

A biologist wants specifically to examine the surfaces of different types of cells in kidney tubules of small mammals. The cells in question can be distinguished by external shape, size, and 3-D characteristics. Which of the following would be the optimum method for her study?

scanning electron microscopy

A newspaper ad for a local toy store indicates that a very inexpensive microscope available for a small child is able to magnify specimens nearly as much as the much more costly microscope available in your college lab. What is the primary reason for the price difference?

The toy microscope magnifies a good deal, but has low resolution and therefore poor quality images

A biologist ground up some plant leaf cells and then centrifuged the mixture to fractionate the organelles. Organelles in one of the heavier fractions could produce ATP in the light, whereas organelles in the lighter fraction could produce ATP in the dark. The heavier and lighter fractions are most likely to contain, respectively

chloroplasts and mitochondria

Which structure is not part of the endomembrane system?

chloroplast

Which structure is common to plant and animal cells?

mitochondrion

Which of the following is present in a prokaryotic cell?

ribosome

Which structure-function pair is mismatched?

microtubule; muscle contraction

Cyanide binds with at least one molecule involved in producing ATP. If a cell is exposed to cyanide, most of the cyanide will be found within the

mitochondria

What is the most likely pathway taken by a newly synthesized protein that will be secreted by a cell?

ER →Golgi →vesicles that fuse with plasma membrane

Which cell would be best for studying lyosomes?

phagocytic white blood cell