MB CH4: Homework
What are the inner folds of the mitochondria called?
cristae
A bacterial cell's DNA is found in its
nucleoid
The plant cell wall
is a protective structure made of cellulose fibrils. The cell wall is a structure that protects the plant cell and is made of cellulose fibrils.
1 meter = _____ centimeters.
100 A centimeter is 1 hundredth of a meter.
The eyepiece of a light microscope has a magnification level of 10x. If you were looking at a paramecium under the lowest-power objective (4x), what would be the total magnification of the microscope at this setting?
40x Total magnification is (4x) × (10x) = 40x.
Which of the following statements about cells is true?
All cells have internal structures that move.
_____ are found only in plant cells, but _____ are found in both plant and animal cells.
Central vacuoles; ribosomes Central vacuoles are found only in plant cells. Ribosomes are found in both plant and animal cells.
Which of the following is part of the endomembrane system?
Golgi apparatus The endomembrane system includes the ER, the Golgi apparatus, lysosomes, and vesicles. It manufactures, processes, and transports lipids and proteins. The Golgi apparatus processes and packages proteins.
Which of the following is a function of the central vacuole?
Storing compounds produced by the cell One of the functions of the central vacuole is to store compounds produced by the cell.
Which of the following describes the function of the chloroplast?
The chloroplast converts light energy to chemical energy. The chloroplast makes food for the plant cell by converting light energy to chemical energy.
A scientist wants to examine living cells lining the respiratory tract to determine how the cells use tiny hairs to move dirt and mucus away from the lungs. Which of the following instruments would be best, and why?
a light microscope, because it allows observations of whole, live cells
A scientist wants to magnify a pollen grain 8,000 times and examine the ridges and pores on its surface. Which of the following instruments would be best?
a scanning electron microscope
Can you label the structures of a plant cell?
a. Central vacuole b. Cell wall c. Chloroplast d. Golgi Apparatus e. Smooth Endoplasmic Reticulum (ER) f. Rough Endoplasmic Reticulum (ER) g. Nucleus h. Mitochondrion
Which type of cytoskeletal protein is also involved in muscle contractions?
actin Actin is a component of the cytoskeletal microfilaments, and also interacts with the protein myosin during muscle contraction.
Cell theory states that
all living things are composed of cells and that all cells come from other cells.
The membranous compartmentalization of a cell
allows different chemical conditions to be maintained in different parts of the cell.
Polypeptides are assembled from _____.
amino acids Proteins are composed of amino acid monomers.
Microfilaments differ from microtubules in that microfilaments
are mainly composed of actin, whereas microtubules are composed of tubulin.
_____ is/are identical in structure to centrioles.
basal bodies Basal bodies and centrioles have identical structures.
Peroxisomes are organelles that are involved in the _____.
breakdown of fatty acids Peroxisomes break down fatty acids for fuel, and they are involved in the detoxification of alcohol and other harmful substances.
Which of the following structures is/are used by prokaryotes for attaching to surfaces?
capsule
A scanning electron microscope is used to study ________, whereas a transmission electron microscope is used to study ________.
cell surfaces; internal cell structures
Which of the following is NOT an example of an organelle found within an animal cell?
cell wall Cell walls are found in plant cells, but not in animal cells.
What name is given to the rigid structure, found outside the plasma membrane, that surrounds and supports the bacterial cell?
cell wall The cell wall is a rigid supporting structure.
The function of mitochondria is
cellular respiration
Which cellular organelle is required for photosynthesis to occur in eukaryotic cells?
chloroplast Chloroplasts contain the green pigment chlorophyll and enzymes and other molecules that function in the photosynthetic production of food.
The complex of proteins and DNA in a nondividing cell is called
chromatin
The _____ is composed of DNA and protein.
chromatin Chromatin is composed of DNA and protein.
Cilia differ from flagella in that
cilia are typically more numerous and shorter than flagella.
Mitochondria differ from chloroplasts in that mitochondria
contain membrane folds called cristae, whereas chloroplasts contain disk-like vesicles in stacks called grana.
The nucleus of a cell
contains DNA
The nucleoid region of a prokaryotic cell
contains the cell's DNA.
The primary role of _____ is to bind animal cells together.
desmosomes The primary role of desmosomes (anchoring junctions) is to bind cells together.
Which technique allowed scientists to figure out that all cells, and not just muscle cells, contained actin filaments?
electron microscopy In the 1960s, staining actin filaments and visualizing them with an electron microscope allowed scientists to discover that these structures are present in all cells.
Which organelles comprise the endomembrane system of a cell?
endoplasmic reticulum, Golgi apparatus, lysosome
Which of the following components is external to the plasma membrane?
extracellular matrix The extracellular matrix is external to the plasma membrane.
It is essential for heart muscle cells to beat in a coordinated fashion. The cell junctions that would best facilitate this are
gap junctions.
Mitochondria and chloroplasts are similar in that they both __________; however, they are different in that only chloroplasts, and not mitochondria, __________.
have a double membrane ... carry out photosynthesis Mitochondria and chloroplasts are both enclosed by membranes. However, mitochondria are the sites of cellular respiration, and only chloroplasts carry out photosynthesis.
The nucleolus __________.
is rich in ribosomal RNA In the nucleolus, ribosomal RNA is synthesized. This RNA combines with special proteins and forms the ribosomes.
The endosymbiosis hypothesis is supported by all of the following pieces of evidence except the fact that
mitochondria lack ribosomes like prokaryotes.
After reading the paragraph below, answer the questions that follow. Much of the intracellular structure of a eukaryote cell is involved in protein synthesis. The accompanying figure shows the amounts of protein in cells at different parts of the cell cycle between two cell divisions. G1is a stage just after the cell has divided, and G2 is the stage just before the cell divides again. S is a stage when the cell is synthesizing material such as DNA, mitochondria, and other organelles. The data show that
not all cells at any given stage have the same amount of protein.
Structures found within a eukaryotic cell and performing specific tasks are collectively termed __________.
organelles These "little organs" perform a variety of functions, including protein production, energy processing, and breakdown of various molecules.
The _____ is the bacterial structure that acts as a selective barrier, allowing nutrients to enter the cell and wastes to leave the cell.
plasma membrane The plasma membrane is selectively permeable.
Of the following organelles, which group is involved in manufacturing the substances needed by the cell?
ribosome, rough endoplasmic reticulum, smooth endoplasmic reticulum Each structure is capable of synthesis.
The Golgi apparatus
stores, modifies, and packages proteins.
Which part of the mitochondrion shown enhances its ability to produce ATP by increasing the surface area of a mitochondrial membrane?
structure D
Membrane proteins are synthesized by ribosomes that are attached to __________.
the endoplasmic reticulum Ribosomes bound to endoplasmic reticulum generally make proteins destined either for inclusion into membranes; for packaging within certain organelles, such as lysosomes; or for export from the cell. The ribosomes attached to its surface are what give the RER its "rough" appearance.
A drug that interferes with microtubule formation is likely to completely disrupt
the movements of sperm cells.
After reading the paragraph below, answer the questions that follow. The skin is the body's largest organ. It's made up of many different types of cells. Oils, produced by the sebaceous glands, prevent the skin from drying and splitting. The pigment melanin, produced by melanocytes in the epidermis, protects the skin from the harmful effects of ultraviolet radiation. Sweat, released through ducts to the skin surface, helps to cool the body. The types of cells that produce these compounds have different numbers of specific organelles, depending on their function. The oil from the sebaceous glands is produced by which of the following cell organelles?
the smooth endoplasmic reticulum
The stroma is the
thick fluid enclosed by the inner chloroplast membrane.
In eukaryotic cells the first step in protein synthesis is the _____.
transferring of information from DNA to messenger RNA Transcription is the first of the two main steps of protein synthesis.
What name is given to the process in which the information encoded in a strand of mRNA is used to construct a protein?
translation Translation is the process by which information encoded in RNA is used to manufacture a polypeptide.
Which of the following structures is essential for the successful operation of the endomembrane system?
transport vesicles Transport vesicles provide a means for moving materials from one part of the endomembrane system to another.
Light microscopes
use light and glass lenses to magnify an image.
A cell is exposed to a substance that prevents it from dividing. The cell becomes larger and larger. This situation
will eventually be problematic, since the cell's ability to absorb nutrients through its outer membrane will not increase as quickly as its cytoplasmic needs.
Which of the following statements regarding plasmodesmata is false?
Plasmodesmata are found in plants and animals.
Dynein feet
are found on microtubules in cilia and flagella and cause movement by grabbing and pulling at adjacent microtubule doublets.
What component of the cell membrane connects signals from the outside of the cell with the inside of the cell and vice versa?
integrins Integrins span the membrane and integrate signals, transmitting information between the extracellular matrix and the cytoskeleton of the cell.
Protein synthesis requires the use of mRNA, which
is translated by the ribosomes into the amino acid sequences of proteins.
The maximum size of a cell is limited by _____.
its need for enough surface area to make exchanges with its environment Because volume increases at a faster rate than surface area, large cells have proportionately less plasma membrane surface area.
Which of the following correctly matches an organelle with its function? The __________ functions in __________.
lysosome ... recycling of damaged organelles Lysosomes contain hydrolytic enzymes that also digest ingested food.
What carries instructions for making proteins from the nucleus into the cytoplasm?
mRNA The "m" in mRNA stands for "messenger"; mRNA is the messenger that carries genetic instructions from the nucleus to the cytoplasm.
When elongated, tube-shaped cells from the lining of the intestine are treated with a certain chemical, the cells sag and become rounded. The internal structures disrupted by this chemical are probably __________.
microtubules Microtubules are cytoskeletal components, and the shape of a cell is determined by its cytoskeleton.
The internal skeleton of a cell is composed of _____.
microtubules, intermediate filaments, and microfilaments These three types of fibers make up the cytoskeleton.
Animal cells are surrounded by a(n) ________________, whereas plant cells are also surrounded by a(n) ________________ .
plasma membrane; cell wall
Dye injected into a plant cell might be able to enter an adjacent cell through a(n) _____.
plasmodesma 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.
Which plant structure is most like gap junctions in animal cells?
plasmodesmata Plasmodesmata form channels between adjacent plant cells which have a similar function to gap junctions in animal cells.
An immune system cell called the plasma cell produces thousands of antibodies (a type of protein) per second for release into the body. What type of intracellular structure would you expect to be very prominent within the cell?
the rough endoplasmic reticulum
Smooth endoplasmic reticulum
stores calcium ions in muscle cells.
Which of these structures stores, modifies, and packages products?
*A* The Golgi apparatus modifies, stores, and packages products of the ER.
Choose the letter that indicates the organelle that contains most of a cell's DNA.
*C* The nucleus contains most of a cell's DNA.
The ____________________ builds compounds, whereas the ________________ breaks things down.
endoplasmic reticulum; lysosome
The DNA-containing region of this bacterial cell is indicated by the letter _____.
*D* The nucleoid region contains DNA.
Which of the following statements regarding the Golgi apparatus is false?
The Golgi apparatus decreases in size when a cell increases its protein production.
Secretory proteins are
released from the cell through the plasma membrane.
The structure that regulates the passage of material into and out of this bacterial cell is indicated by the letter _____.
*C* The plasma membrane is selectively permeable.
Which of these provides the cell with structural support?
*D* Microfilaments are a component of the cytoskeleton.
Which of these is the double membrane that encloses the nucleus?
*E* This is the nuclear envelope.
Drag the terms on the left to the appropriate blanks on the right to complete the sentences. The nucleus contains DNA organized into chromosomes. The nucleus directs most activities of the cell and is surrounded by a nuclear envelope. Nuclear pores allow materials, such as RNA, to pass out of the nucleus.
1. *DNA* is the self-replicating material present in nearly all living organisms; it is the main constituent of chromosomes and the carrier of genetic information. 2. *RNA* is used in all steps of protein synthesis and carries the genetic information of many viruses. 3. The *NUCLEUS* is the most prominent membrane-bound organelle in eukaryotic cells, and it houses most of a cell's DNA. 4. The *NUCLEAR ENVELOPE* is the two-layered membrane that encases the nucleus of a eukaryotic cell, separating the nucleus from the cytoplasm. 5. A protein-lined channel in the nuclear envelope that regulates the transportation of molecules between the nucleus and the cytoplasm is called a *NUCLEAR PORE*. 6. The round body that sits inside the nucleus of a eukaryotic cell and makes ribosomal subunits from proteins and ribosomal RNA is known as the *NUCLEOLUS*. 7. *CHROMOSOMES* are tightly coiled bundles of DNA and protein found in the nucleus of most living cells.
Endosymbiosis is the internalization of one species by a host species. According to the endosymbiotic hypothesis, internalized prokaryotes eventually evolved into eukaryotic organelles. Drag the images to the targets of Group 1 in the order of the endosymbiotic hypothesis. Then match each description with the appropriate step.
1. Ancestral cell with nucleus and endomembrane system. 2. Oxygen-metabolizing bacterium begins to be engulfed by ancestral cell. 3. Oxygen-metabolizing bacterium is fully engulfed in the cell. 4. Photosynthetic prokaryote begins to be engulfed by ancestral cell. 5. Photosynthetic prokaryote is fully engulfed, resulting in a eukaryotic cell with organelles. **** Ancestral prokaryotic cells evolved into the first eukaryotic cells through an inward folding of the plasma membrane and the engulfment and incorporation of other free-living prokaryotic cells. Those engulfed cells functioned as organelles that metabolize oxygen and photosynthesize.
One centimeter = ________ millimeters.
10
A normal size range for a typical eukaryotic cell is _____.
10 to 100 micrometers
The diameter of most animal and plant cells ranges from
10 to 100 micrometers.
A 100 mm x 100 mm x 100 mm cell has a surface area that is _____ and a volume that is _____. When this volume is broken into many smaller cells, that are 10 mm x 10 mm x 10 mm, the sum of the surface areas of the smaller cells is _____ than the surface area of the initial cell.
60,000 mm2 ... 1,000,000 mm3 ... larger The smaller cell has a larger surface (600 mm2) to volume (1,000 mm3) ratio. This accounts for why most cells are microscopic.
A child dies following a series of chronic bacterial infections. At the autopsy, the physicians are startled to see that the child's white blood cells are loaded with vacuoles containing intact bacteria. Which of the following explanations could account for this finding?
A defect in the lysosomes of the white blood cells prevented the cells from destroying engulfed bacteria.
Drag the labels onto the diagram to identify the structures of an animal cell.
A. Cytoskeleton B. Ribosomes C. Nucleus D. Smooth Endoplasmic Reticulum (ER) E. Cytosol F. Golgi Apparatus G. Rough Endoplasmic Reticulum (ER) H. Mitochondrion I. Plasma Membrane
Drag the labels to the appropriate locations in this diagram.
A. Fimbriae B. Nucleoid C. Plasma Membrane D. Cell Wall E. Capsule F. Flagella G. Bacterial Chromosome H. Ribosomes
Drag the labels to the appropriate locations in this diagram. First drag pink labels to pink targets to label the two host cells. Then drag blue labels to blue targets to label the structures and endosymbionts of the two cells.
A. Oxygen-using prokaryote B. Mitochondrion C. Nucleus D. Endoplasmic Reticulum E. Host cell: Ancestor of all eukariots F. Photosynthetic prokaryote G. Chloroplast H. Host cell: Ancestor of photosynthetic eukaryotes
The purpose of cellular respiration is the production of __________.
ATP Cellular respiration produces ATP for use in the cell's enzyme reactions that require energy.
Cyanide inhibits mitochondrial function; as a result, the rate of
ATP synthesis decreases.
Which of the following statements regarding cells is false?
All cells have a cell wall.
Why do both mitochondria and chloroplasts possess circular chromosomes?
Both mitochondria and chloroplasts descended from free-living prokaryotes engulfed and maintained by early eukaryotic cells. Endosymbiotic theory explains the basis for a variety of peculiar features shared between mitochondria, chloroplasts, and prokaryotes.
Which of the following is NOT a feature of both mitochondria and chloroplasts?
Both possess pigments active in photosynthesis. Such pigments are possessed by chloroplasts, but not by mitochondria.
After reading the paragraph below, answer the questions that follow. Much of the intracellular structure of a eukaryote cell is involved in protein synthesis. The accompanying figure shows the amounts of protein in cells at different parts of the cell cycle between two cell divisions. G1is a stage just after the cell has divided, and G2 is the stage just before the cell divides again. S is a stage when the cell is synthesizing material such as DNA, mitochondria, and other organelles. Which of these conclusions cannot reasonably be drawn from the graph?
Cells export a large amount of protein following cell division.
Which of the following statements about cellular metabolism is false?
Cellular metabolism occurs in animal but not plant cells.
__________ is the most prevalent glycoprotein in the extracellular matrix
Collagen Collagen can comprise 40% of the protein in your body.
Which of the following statements about electron microscopes is true?
Electron microscopes focus electron beams to create a magnified image of an object.
_____ are surface appendages that allow a bacterium to stick to a surface.
Fimbriae Fimbriae enable bacterial cells to stick to a surface.
_____ aid in the coordination of the activities of adjacent animal cells.
Gap (communicating) junctions Gap junctions allow for the passage of material between cells, thus facilitating communication between these cells.
A researcher made an interesting observation about a protein made by the rough endoplasmic reticulum and eventually used to build a cell's plasma membrane. The protein in the membrane was actually slightly different from the protein made in the ER. The protein was probably altered in the _____.
Golgi apparatus Vesicles carrying proteins from the ER fuse with the Golgi apparatus, where the proteins may be altered.
Which of the following statements about internal membranes in eukaryotic cells is false?
In eukaryotic cells, internal membranes standardize the internal environment of all cellular organelles.
Your throat is dry, and you want the last cough drop in the box to last a long time in your mouth. What should you do?
Keep the cough drop whole. This maintains the smallest surface-to-volume ratio and slows the dissolution of the cough drop.
Which of the following statements about lysosomes is false?
Lysosomes synthesize proteins from the recycled amino acids.
Drag the labels onto the flowchart to trace the movement of proteins through the endomembrane system and out of the cell.
Manufacturing: Rough ER Transport: Vesicle from ER Processing: Golgi apparatus Transport: Vesicle from Golgi Secretion: Plasma membrane
Which plant cell organelle converts chemical fuel into packets of chemical energy that can power the cell?
Mitochondrion In both plant and animal cells, it's the mitochondria that convert chemical fuel into packets of chemical energy that can power the cell.
Drag the correct description under each cell structure to identify the role it plays in the cell.
Nucleus: Stores the genetic information of the cell. Lysosome: Breaks down macromolecules using digestive enzymes. Mitochondrion: Converts chemical fuel into packets of chemical energy that can power the cell. Ribosome: Works with mRNA to synthesize proteins. Smooth ER: Site of lipids synthesis.
Which of the following statements about the cytoskeleton is false?
Once laid down, the elements of the cytoskeleton are fixed and remain permanently in place.
Which of the following statements about plant cell walls is false?
Plant cell walls protect plant cells by forming an impermeable layer around the cell.
________ cells lack a membrane-enclosed nucleus.
Prokaryotic
What name is given to the process in which pre-mRNA is edited into mRNA?
RNA processing RNA processing edits the RNA transcript that has been assembled along a DNA template.
The accompanying figure shows data from an experiment in which researchers measured how far dynein (a motor protein) traveled in the presence and absence of dynactin (another type of protein). The y-axis shows the percent of the time that the researchers observed either dynein or dynein + dynactin "walking" a certain distance on a microtubule. What can you conclude from these data?
The addition of dynactin caused dynein to travel farther along the microtubule.
Which of the following is the most likely consequence for a cell lacking functional lysosomes?
The cell becomes crowded with undigested wastes. A lysosome is a membrane-enclosed sac of hydrolytic enzymes that the cell uses to digest macromolecules—in some cases, recycling the cell's own organic material.
Which of the following statements about the functions of a plant cell central vacuole is false?
The central vacuole of a plant cell may digest chemicals for recycling.
Which of the following statements regarding the endomembrane system is false?
The endomembrane system is a system of interrelated membranes that are all physically connected.
What is the relationship between the Golgi apparatus and the plasma membrane?
The finished products of the Golgi apparatus may leave the cell through vesicles that fuse with the plasma membrane. Transport vesicles from the Golgi move to the plasma membrane for export. In some cases the finished products become part of the plasma membrane or part of another organelle.
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 a layer of epithelial cells.
One function of the central vacuole in plant cells is facilitating cell growth: the central vacuole absorbs water and increases in size, expanding the volume and size of the plant cell while doing so. Animal cells, however, do not grow by this method. What is an essential difference between animal and plant cells that could explain how a plant cell can withstand this expansion of the central vacuole?
The plant cell wall provides a more rigid structure. The plant cell can use the central vacuole for growth because the cell wall is rigid.
How are cell surface proteins exported out of the cell?
The protein is folded, then packaged for transport to the Golgi apparatus. The protein structure is critical to the normal function of the protein. Once folded, then it will be transported to the Golgi apparatus via a transport vesicle.
After reading the paragraph below, answer the questions that follow. Studies of the endomembrane system often involve the use of a protein that can emit a green fluorescence (glow). A researcher wants to make a video of cell behavior, so she initially labels the outer nuclear envelope of a cell with the fluorescent tag and records a video for several hours. Later, she sees that the tag is part of a transport vesicle very close to the plasma membrane. What likely happened during the intervening time?
The tag was seen in the Golgi before being seen in a transport vacuole.
What do the rough endoplasmic reticulum, Golgi apparatus, and lysosomes have in common?
They are constructed of interrelated membranes. Each of these organelles is a member of the endomembrane system and is constructed of the same type of membrane.
The endosymbiosis hypothesis proposes that
a small cell lived inside a larger cell to the benefit of both cells.
Resolution is the
ability of an optical instrument to show two close objects as separate.
A certain cell has a dense nucleoid region, ribosomes, but no membrane-enclosed organelles. Based on this information, it could be __________.
an archaean Archaea and other prokaryotes have no internal membrane-enclosed organelles. However, they do have both ribosomes and a region called the nucleoid region where their DNA can be found.
After reading the paragraph below, answer the questions that follow. The skin is the body's largest organ. It's made up of many different types of cells. Oils, produced by the sebaceous glands, prevent the skin from drying and splitting. The pigment melanin, produced by melanocytes in the epidermis, protects the skin from the harmful effects of ultraviolet radiation. Sweat, released through ducts to the skin surface, helps to cool the body. The types of cells that produce these compounds have different numbers of specific organelles, depending on their function. The epidermis is made up of epithelial cells which are held tightly together side by side to prevent pathogens from entering the body and to prevent unnecessary water loss. What type of junction holds epithelial cells together to achieve this function?
anchoring junction
Skin cells are fastened into strong sheets by
anchoring junctions
In the plasma membrane, the phospholipid heads
are hydrophilic and face outward toward the aqueous solution on both sides of the membrane.
You are told that the cells on a microscope slide are plant, animal, or bacterial. You look at them through a microscope and see cell walls and membrane-bound organelles. You conclude correctly that the cells
are plant cells.
Which of the following cells has the greatest surface-to-volume ratio?
bacterium
Mitochondria are found in _____.
both plant cells and animal cells Mitochondria are found in nearly all eukaryotic cells.
Which is a typical function of lysosomes?
breaking down of damaged organelles, such as mitochondria Lysosomes do break down damaged organelles; lysosomes are rarely found in plant cells.
Tay-Sachs disease
causes an accumulation of lipids in brain cells.
Many researchers think that the first eukaryotic cells obtained energy for life-sustaining functions from organic compounds. Given this information, which of the following organelles most likely appeared last in eukaryotic cells?
chloroplast If the earliest eukaryotic cells had contained chloroplasts, they would not have had to obtain organic compounds through food.
What are the three organelles that plant cells have but animal cells do not?
chloroplast, central vacuole, cell wall
Unlike animal cells, plant cells have ________ and ________. Unlike plant cells, animal cells have ________.
chloroplasts; cell walls; centrioles
Plant cells have two energy-related organelles. ________________ harness light energy to create sugars and ________________ break down these sugars to create ATP.
chloroplasts; mitochondria
During cell reproduction, chromatin fibers coil up into structures called
chromosomes.
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, which is structurally very similar to a centriole.
The function of the chloroplast is to _____.
convert light energy to chemical energy The function of the chloroplast is to convert light energy from the sun to the chemical energy of a glucose molecule.
The ________ of a mitochondrion is/are an adaptation that increases the surface area and enhances a mitochondrion's ability to produce ATP.
cristae
What mitochondrial feature enhances cellular respiration?
cristae These folds increase the surface area of the membrane, allowing more proteins to be embedded and thus enhancing the ability of the mitochondrion to produce ATP.
The structural framework in a cell is the
cytoskeleton The cytoskeleton is the structural framework in a cell ("cyto" refers to cell and "skeleton" refers to a structural framework).
Where would ribosomes be located that are responsible for producing enzymes which play a role in sugar metabolism?
cytosol The first steps of sugar metabolism occur within the cytosol. Therefore, the ribosomes in the cytosol are responsible for making the necessary enzymes.
After reading the paragraph below, answer the question that follows. Studies of the endomembrane system often involve the use of a protein that can emit a green fluorescence (glow). A researcher wants to make a video of cell behavior, so she initially tags the outer nuclear envelope of a cell with the fluorescent tag and records for several hours. Later, she sees that the tag is part of a secretory vesicle. The ability to stain protein molecules with a fluorescent dye would most clearly allow researchers to go beyond what they could previously detect with a microscope by allowing them to
detect ribosome activity.
After reading the paragraph below, answer the questions that follow. Much of the intracellular structure of a eukaryote cell is involved in protein synthesis. The accompanying figure shows the amounts of protein in cells at different parts of the cell cycle between two cell divisions. G1is a stage just after the cell has divided, and G2 is the stage just before the cell divides again. S is a stage when the cell is synthesizing material such as DNA, mitochondria, and other organelles. The technique used to produce the data displayed might be useful for a cancer biologist who wishes to
determine the effect of drugs on protein synthesis at various times in the cell cycle.
Which of the following are stored in the lysosomes of the cell?
digestive enzymes The lysosome is a sac of digestive enzymes.
Cilia and flagella move thanks to the energy provided by __________, a special motor protein that can harvest energy from ATP.
dynein arms The dynein arms of cilia and flagella break down ATP for energy for motility.
The contractile vacuole __________.
eliminates excess water from the cytoplasm of freshwater protists It keeps the freshwater protists in osmotic balance.
Most animal cells are
embedded in an extracellular matrix.
Where are chlorophyll molecules located within the chloroplasts?
embedded in the thylakoid membrane Chlorophyll molecules are embedded within the thylakoid membrane, which is the most extensive membrane system within plant cells.
After reading the paragraph below, answer the questions that follow. Studies of the endomembrane system often involve the use of a protein that can emit a green fluorescence (glow). A researcher wants to make a video of cell behavior, so she initially labels the outer nuclear envelope of a cell with the fluorescent tag and records a video for several hours. Later, she sees that the tag is part of a transport vesicle very close to the plasma membrane. The fluorescent tag likely became incorporated into which of the following organelles during the video?
endoplasmic reticulum
What type of microscopy allowed scientists to visualize the cytoskeleton in living cells?
fluorescence microscopy
Hexokinase is an enzyme that is involved with glycolysis (the breakdown of glucose for energy release) that occurs in the cytoplasm. What cellular structure makes hexokinase?
free ribosomes
Which of the following structures is directly involved in the passage of electrical signals between cells as, for example, in the vertebrate heart?
gap junctions Communicating junctions provide cytoplasmic channels between adjacent cells that allow ions to flow, coordinating the contractions of those cells.
A manufacturing company dumps its wastes into a nearby pond. One of the wastes is found to paralyze the contractile vacuoles of certain protists. A biologist looking at individual samples of these organisms taken from the pond would find that they
have gained water and burst.
What changes would you expect to see in the liver cells of someone suffering from chronic alcoholism?
increased levels of endoplasmic reticulum activity The smooth endoplasmic reticulum of liver cells has enzymes that are involved in alcohol metabolism. This organelle is affected in the liver cells of alcoholics.
Signals are transmitted between the extracellular matrix to the cytoskeleton through __________ proteins.
integrin Integrins span the plasma membrane, and can thus directly interact with both the extracellular matrix and the cytoskeleton.
The extracellular matrix attached to cells via glycoproteins may then bind to ________ in the plasma membrane.
integrins
Which of the following would be most affected by a mutation that prevented cells from forming tight junctions?
integrity of the inner lining of the digestive tract
Bacterial cells are prokaryotic; unlike a typical eukaryotic cell, they _____.
lack a nucleus The term prokaryotic literally translates as "before nucleus."
A disease called primary ciliary dyskenisia is characterized by abnormal ciliary movements. In these cilia, microtubule functioning is disrupted due to microtubules missing an essential component. This disease could be caused by __________.
lack of dynein proteins Dynein is part of the proteins that make up microtubules. Defects in dynein proteins are responsible for this disease.
Which organelle plays a role in intracellular digestion?
lysosome The prefix "lyso-" means decomposition.
The cells of a person with adrenoleukodystrophy (ALD) swell with a buildup of fatty acids. In other words, fatty acids are not being broken down. Which organelle is most likely failing to function correctly?
lysosome This organelle functions to remove unwanted or unneeded material from the cell.
Which of the following organelles is found only in animal cells and NOT in most plant cells?
lysosome This organelle is found only in animal cells. Most plant cells do not have a lysosome.
Which of the following organelles breaks down worn-out organelles?
lysosomes Lysosomes contain digestive enzymes and break down worn-out organelles.
Tay-Sachs disease results from the malfunction of
lysosomes.
RNA processing converts the RNA transcript into _____.
mRNA The editing of the RNA transcript produces mRNA.
The main function of the rough endoplasmic reticulum is the production of
membrane and proteins secreted by the cell.
Mitochondria appear in the greatest numbers in cells that are _____.
metabolically active Mitochondria are the sites of cellular respiration, the catabolic process that generates ATP by extracting energy from food molecules, with the help of oxygen.
The protein actin is a component of a(n) __________.
microfilament Microfilaments are primarily composed of actin, a globular protein.
The cilia and flagella of eukaryotic cells are composed of _____.
microtubules Eukaryotic cilia and flagella are composed of microtubules.
Which of these are hollow rods that shape and support the cell?
microtubules Microtubules are rods that also play a role in organelle movement.
Which of the following cytoplasmic structures functions in the transport of vesicles from the endoplasmic reticulum to the Golgi apparatus?
microtubules Vesicles travel along microtubules as they move from one part of the cell to another.
According to the accompanying figure, which of the following are large enough to see in the light microscope?
mitochondria
After reading the paragraph below, answer the questions that follow. Studies of the endomembrane system often involve the use of a protein that can emit a green fluorescence (glow). A researcher wants to make a video of cell behavior, so she initially labels the outer nuclear envelope of a cell with the fluorescent tag and records a video for several hours. Later, she sees that the tag is part of a transport vesicle very close to the plasma membrane. The fluorescent tag likely did not become incorporated into which of the following organelles?
mitochondria
Where in a cell is ATP made?
mitochondria ATP is made in mitochondria.
Which of the following is NOT a part of the endomembrane system?
mitochondria Mitochondria are involved in energy processing and are not members of the endomembrane system.
Which cell structure is responsible for metabolism?
mitochondrion Mitochondria are involved in the process of converting the chemical energy of food to ATP.
Which of these organelles carries out cellular respiration?
mitochondrion Mitochondria convert the chemical energy of organic molecules to chemical energy in the form of ATP.
The membranes of the endoplasmic reticulum are continuous with the membranes of the __________.
nuclear envelope These two membranes are continuous.
Which of the following structures is exclusively associated with prokaryotic cells?
nucleoid
Where is a bacterial cell's DNA found?
nucleoid region Bacteria lack a nucleus; their DNA is found in the nucleoid region.
Ribosomal subunits are manufactured by the _____.
nucleolus
Where is the genetic information of the cell stored?
nucleus DNA is the genetic information of the cell, and it is stored in the nucleus.
Most of the DNA in a eukaryotic cell is in the _____.
nucleus The nucleus contains most of the genes that control the eukaryotic cell.
The genetic center of the eukaryotic cell is the __________.
nucleus The nucleus is the genetic center of the cell, and it contains the hereditary information.
Digestive cells produce and secrete many enzymes that break down ingested food. These cells have a large number of ribosomes __________.
on the rough endoplasmic reticulum The rough endoplasmic reticulum is responsible for producing proteins that will be inserted into membranes, packaged in certain organelles, or exported from the cell.
Flagella and cilia are both composed of tubulin subunits. Despite this similarity, key differences exist between these two structures. For example, __________.
only cilia move as a coordinated team Cilia work together in a coordinated team, much like the oars on a rowing team. This allows them to propel fluids along their surfaces for locomotion or feeding.
Which organelle is involved in the breakdown of fatty acids and the detoxification of alcohol?
peroxisome
Which of these organelles produces H2O2as a by-product?
peroxisome Peroxisomes produce hydrogen peroxide as a by-product of their metabolic processes.
The endomembrane system includes all of the following organelles except the
peroxisome.
Which of the following cell structures are associated with the breakdown of harmful substances?
peroxisomes
The function of chloroplasts is
photosynthesis.
You have identified a new organism. It has ribosomes, plasmodesmata, and cell walls made of cellulose. This new organism is most likely a(n) __________.
plant Plant cells have cell walls that are made of cellulose and plasmodesmata, which are cytoplasmic channels that connect adjacent cells.
Chloroplasts are found in __________.
plant cells and some protists Chloroplasts are lens-shaped organelles found in leaves and other green organs of plants and photosynthetic protists.
Which location in the cell is unlikely to contain ribosomes or ribosomal subunits?
plasma membrane
The _____ is a selective barrier, regulating the passage of material into and out of the cell.
plasma membrane The plasma membrane regulates the passage of material into and out of the cell.
What structure acts as a selective barrier, regulating the traffic of materials into and out of the cell?
plasma membrane The plasma membrane surrounds the cell and regulates the movement of materials into and out of the cell.
The cell junctions in plant cells that provide channels between adjacent cells are generally _____.
plasmodesmata Plasmodesmata form channels between adjacent plant cells.
In plants, __________ are the cell junctions that allow the free exchange of small molecules that assist in communication. In animal cells, similar cell junctions are known as __________.
plasmodesmata ... gap junctions Plant cells are interconnected by plasmodesmata, which form tubelike structures that penetrate through the cell walls. Gap junctions are formed by specialized channels found in animal cells. Both Plamodesmata and gap junctions allow the free exchange of small molecules and help coordinate the activities of neighboring cells.
Which of the following would distinguish a bacterial cell from an animal cell?
presence of a cell wall Prokaryotic cells have cell walls. Some eukaryotic cells do also, but animal cells do not.
Contractile vacuoles
prevent cells from bursting as a result of the influx of excess water.
A woman is having trouble becoming pregnant. Examination of her partner's sperm indicates that dynein feet are missing from the flagella in his sperm cells. A physician explains that this could interfere with fertility by
preventing the sperm from swimming to the egg cell.
Archaea are composed of ________ cells.
prokaryotic
What is the function of a bacterium's capsule?
protection A bacterium's capsule has a protective role.
After reading the paragraph below, answer the questions that follow. Much of the intracellular structure of a eukaryote cell is involved in protein synthesis. The accompanying figure shows the amounts of protein in cells at different parts of the cell cycle between two cell divisions. G1is a stage just after the cell has divided, and G2 is the stage just before the cell divides again. S is a stage when the cell is synthesizing material such as DNA, mitochondria, and other organelles. The protein measured in the cells was likely synthesized by
ribosomes
_____ are the sites of protein synthesis.
ribosomes
Which of the following structure(s) is/are found in prokaryotic cells?
ribosomes Both prokaryotic and eukaryotic cells do have ribosomes.
In a bacterium, where are proteins synthesized?
ribosomes Ribosomes are involved in the manufacture of polypeptides (proteins).
One of the ways smooth endoplasmic reticulum (ER) differs from rough endoplasmic reticulum is that rough ER is covered by
ribosomes Ribosomes dock on the rough ER, and proteins are completed inside the rough ER.
After reading the paragraph below, answer the questions that follow. The skin is the body's largest organ. It's made up of many different types of cells. Oils, produced by the sebaceous glands, prevent the skin from drying and splitting. The pigment melanin, produced by melanocytes in the epidermis, protects the skin from the harmful effects of ultraviolet radiation. Sweat, released through ducts to the skin surface, helps to cool the body. The types of cells that produce these compounds have different numbers of specific organelles, depending on their function. Melanocytes use many enzymes to produce melanin. Based on their function, you would expect melanocytes in the skin to have a higher than usual number of
ribosomes.
Insulin is a protein that is produced by pancreatic cells and secreted into the bloodstream. Which of the following options correctly lists the order of the structures through which insulin passes from its production to its exit from the cell?
rough ER, transport vesicles, Golgi apparatus, transport vesicles, cell membrane
Which of these manufactures cellular membranes by adding membrane proteins and phospholipids to its own membrane?
rough endoplasmic reticulum As membrane proteins grow from ribosomes on rough ER, the proteins are embedded into the rough ER membrane.
The cells that produce hair made of protein contain a lot of ________, while the cells that produce the oils that coat the hair contain a lot of ________.
rough endoplasmic reticulum; smooth endoplasmic reticulum
The architecture of cell surfaces can be viewed in the most detail using a __________.
scanning electron microscope The scanning electron microscope uses an electron beam to provide a detailed picture of the outlines of the surface.
You would expect a cell with an extensive Golgi apparatus to _____.
secrete a lot of material The Golgi apparatus intercepts ER vesicles, modifies the contents for export, and repackages the material in a Golgi vesicle that can fuse with the plasma membrane.
Pancreatic cells produce large amounts of protein. About how many ribosomes would you expect there to be in a pancreatic cell?
several million There are several million ribosomes in cells, such as the cells in the pancreas that produce digestive enzymes.
A basal body is
similar in structure to centrioles.
Where is calcium stored?
smooth endoplasmic reticulum In addition to storing calcium, the smooth ER also plays a role in detoxification and lipid synthesis.
In muscle cells, the _____ is/are specialized for the storage and release of calcium.
smooth endoplasmic reticulum When a muscle cell is stimulated by a nerve impulse, calcium is released from the smooth ER, triggering the contraction.
Where are lipids made in the cell?
smooth endoplasmic reticulum (ER)
Which tissue would likely contain large amounts of anchoring junctions?
stomach tissue Stomach tissue is muscle tissue that initiates movement (churning of food) and expansion.
The plasma membrane would fit into which general function category?
support, movement, and communication The plasma membrane is an important structure for cell communication with the external environment.
Intermediate filaments
surround the nucleus.
Which of the following is a function of the rough endoplasmic reticulum?
synthesizing receptor proteins These proteins are made by the rough endoplasmic reticulum and then processed by the Golgi apparatus before being inserted into the cell membrane.
Lysosomes are derived from __________ and function in __________.
the Golgi apparatus and rough endoplasmic reticulum ... digestion of worn-out organelles Lysosomes are membrane-enclosed sacs of hydrolytic enzymes that are used to digest macromolecules. They are produced by budding off the Golgi apparatus.
The term resolving power refers to _____.
the clarity of the image in showing two objects as separate
To enter or leave any cell, substances must pass through _____.
the plasma membrane The plasma membrane defines the boundary of the cell.
GPCRs are receptor proteins found in the plasma membrane that are important for cellular communication. What cellular structure makes GPCRs?
the rough endoplasmic reticulum
Which of these cell junctions form a barrier to the passage of materials?
tight junctions Tight junctions form a barrier that prevents fluids from moving between cells.
The function of the nucleolus is
to manufacture ribosomal RNA.
What name is given to the process in which a strand of DNA is used as a template for the manufacture of a strand of pre-mRNA?
transcription Transcription is the process by which a DNA template is used for the manufacture of several different types of RNA.
Which microscope would be best suited to the measurement of the internal structures of a bacterial cell?
transmission electron microscope Specimens are cut into extremely thin sections, which allows viewing of the components contained within the cell. The transmission electron microscope also has great resolving power, which allows the structures to be differentiated.
If you wished to clearly observe the organelles inside of a white blood cell, which type of microscope would you choose?
transmission electron microscope This type of microscope allows you to view internal structures of living cells.
A pathologist who wants to examine a patient's liver cells to determine if the mitochondria have an internal structural defect will likely need to use a
transmission electron microscope.
Which of the following correctly matches an organelle with its function? The _____ functions in _____.
vacuole ... storage Plant cells have a central vacuole, whereas most animal cells have several smaller vacuoles located throughout the cytoplasm.
As cell size increases, the
volume increases proportionally more than the surface area.
Which of the following clues would tell you whether a cell is prokaryotic or eukaryotic?
whether or not the cell is partitioned into compartments by internal membranes Prokaryotic cells lack any internal membranous compartmentalization whereas eukaryotic cells have membrane-bound organelles.