Biology II - Chapter 4

One meter consists of _____ millimeters and _____centimeters. How many millimeters are in one centimeter?

1,000: 100: 10 The table shows that 1 meter consists of 1,000 millimeters or 100 centimeters. To find the number of millimeters in a centimeter, divide 1,000 by 100. The result is 10 millimeters. In general, the prefixes "centi" (for 100) and "milli" (for 1,000) can help you understand these terms. One meter consists of 1,000 millimeters and 100 centimeters. How many millimeters are in one centimeter? 10

What four cellular components are shared by prokaryotic and eukaryotic cells?

1. DNA as genetic material 2. ribosomes 3. plasma membrane 4. cytosol

1 meter = _____ centimeters.

100 A centimeter is 1 hundredth of a meter.

Which of these structures stores, modifies, and packages products?

A. golgi apparatus The Golgi apparatus modifies, stores, and packages products of the ER.

Eukaryotic Cells and the Process of Endosymbiosis Step #1

Ancestral cells with nucleus and endomembrane system.

The structure that regulates the passage of material into and out of this bacterial cell is indicated by the letter _____.

C. plasma membrane The plasma membrane is selectively permeable.

Tour of a Plant Cell -- Organelle Functions Central Vacuole

Central Vacuole: Regulates cytoplasm composition, creates internal pressure, and stores cell compounds.

Tour of a Plant Cell -- Organelle Functions Chloroplast

Chloroplast: Makes food by converting light energy into chemical energy.

Describe two different ways in which cilia can function in organisms.

Cilia may propel a cell through its environment or sweep a fluid environment past the cell.

Which of these provides the cell with structural support?

D. microfilaments Microfilaments are a component of the cytoskeleton.

The DNA-containing region of this bacterial cell is indicated by the letter _____.

D. nucleoid region The nucleoid region contains DNA.

Tour of a Plant Cell -- Organelle Functions Golgi Apparatus

Golgi Apparatus: Modifies and packages proteins.

Can you identify the functions of the parts of an animal cell? Mitochondrion

Mitochondria convert chemical fuel into packets of chemical energy that can power the cell.

Tour of a Plant Cell -- Organelle Functions Mitochondrion

Mitochondrion: Converts chemical fuel into packets of chemical energy (ATP) that can power the cell.

Can you identify the functions of the parts of an animal cell? Nucleus

The nucleus stores the genetic information of the cell

Pancreatic cells produce large amounts of enzymes for export into the digestive system. By contrast, muscle cells do NOT export digestive enzymes. How do you think that the number of ribosomes compares in the two cell types?

The pancreatic cell has many more ribosomes than the muscle cell. There are several million ribosomes in cells like those in the pancreas that produce digestive enzymes. The main job of the muscle cell is contraction, not protein synthesis, so it needs far fewer ribosomes.

The _____ is composed of DNA and protein.

chromatin Chromatin is composed of DNA and protein.

__________ is the most prevalent glycoprotein in the extracellular matrix. Hint: Consider the glycoproteins found in the extracellular matrix. Review figure 4.19.

collagen Collagen can comprise 40% of the protein in your body.

The most abundant glycoprotein in the extracellular matrix (ECM) is __________. This protein attaches to __________, which are proteins in the plasma membrane that connect the ECM with the inside of the cell. Hint: Examine Figure 4.19 and recall the glycoprotein that makes up 40% of the proteins in the body.

collagen; integrins Collagen is the most abundant glycoprotein in the extracellular matrix, as well as accounting for about 40% of the protein in the entire body. Integrins are membrane-spanning proteins that transmit signals between the ECM and the cytoskeleton, where they attach to intercellular microfilaments. The most abundant glycoprotein in the extracellular matrix (ECM) is collagen. This protein attaches to integrins, which are proteins in the plasma membrane that connect the ECM with the inside of the cell.

Which technique allowed scientists to figure out that all cells, and not just muscle cells, contained actin filaments? Hint: This technique was applied to actin filament studies in the 1960s.

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.

The contractile vacuole __________. Hint: Consider the types of cells that have contractile vacuoles.

eliminates excess water from the cytoplasm of freshwater protists It keeps the freshwater protists in osmotic balance.

_____ 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.

Bacterial cells are prokaryotic; unlike a typical eukaryotic cell, they _____. Recall that prokaryotic cells lack many of the internal structures found in eukaryotic cells.

lack a nucleus The term prokaryotic literally translates as "before nucleus."

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? Hint: This organelle has many functions, including the breakdown of damaged organelles and digestive functions.

lysosome This organelle functions to remove unwanted or unneeded material from the cell.

Which of the following correctly matches an organelle with its function? The __________ functions in __________. Hint: Consider the different functions of the individual organelles.

lysosome ... recycling of damaged organelles Lysosomes contain hydrolytic enzymes that also digest ingested food. The lysosome functions in recycling of damaged organelles.

Which of the following organelles breaks down worn-out organelles? Hint: Think about the organelle that contained digestive enzymes and fused with a worn-out mitochondrion in the animation.

lysosomes Lysosomes contain digestive enzymes and break down worn-out organelles.

Which of the following organelles is found only in animal cells and NOT in most plant cells? Hint: Examine Figures 4.4A and 4.4B (and associated text) to see organelles that are only found in one type of cell.

lysosomes This organelle is found only in animal cells. Most plant cells do not have a lysosome.

What carries instructions for making proteins from the nucleus into the cytoplasm? Hint: Remember the red molecules that traveled from the nucleus to the cytoplasm in the animation.

mRNA The "m" in mRNA stands for "messenger"; mRNA is the messenger that carries genetic instructions from the nucleus to the cytoplasm.

RNA processing converts the RNA transcript into _____.

mRNA The editing of the RNA transcript produces mRNA.

Which of the following is the correct pairing of a cytoskeletal structure and its approximate diameter? Hint: It's a good idea to develop a mnemonic device for this—you will be seeing these structures throughout biology.

microtubules: 25nm Mictotubules, with an approximate diameter of 25 nm, are the thickest cytoskeletal fiber. They help shape and support the cell, serve as tracks for protein movement, guide the movements of chromosomes in cell division, and are the main components of cilia and flagella.

Where in a cell is ATP made? Hint: Remember where the ATP molecules (starbursts) were made in the animation.

mitochondria ATP is made in mitochondria.

Which of the following is NOT a part of the endomembrane system? Hint: Not all organelles are part of the endomembrane system.

mitochondria Mitochondria are involved in energy processing and are not members of the endomembrane system.

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.

Where is a bacterial cell's DNA found?

nucleoid region Bacteria lack a nucleus; their DNA is found in the nucleoid region.

In the most general sense, which of the following is the correct description of cellular respiration? Hint: Recall the gases we inhale and exhale, and our cells' energy needs.

oxygen is used, carbon dioxide is released, ATP is created Cellular respiration, which occurs in mitochondria, uses oxygen, releases carbon dioxide, and creates ATP, the fuel for cellular work.

Which of these organelles produces H2O2 as a by-product?

peroxisomes Peroxisomes produce hydrogen peroxide as a by-product of their metabolic processes.

You have identified a new organism. It has ribosomes, plasmodesmata, and cell walls made of cellulose. This new organism is most likely a(n) __________. Hint: What group of organisms has cells with these properties?

plant Plant cells have cell walls that are made of cellulose and plasmodesmata, which are cytoplasmic channels that connect adjacent cells.

In a bacterium, where are proteins synthesized?

ribosomes Ribosomes are involved in the manufacture of polypeptides (proteins).

_____ are the sites of protein synthesis.

ribosomes Ribosomes are the site of protein synthesis.

One of the ways smooth endoplasmic reticulum (ER) differs from rough endoplasmic reticulum is that rough ER is covered by... Hint: Think of the structures that docked on the rough ER in the animation.

ribosomes Ribosomes dock on the rough ER, and proteins are completed inside the rough ER.

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 architecture of cell surfaces can be viewed in the most detail using a __________. Hint: Consider the resolving power of each of these types of microscopes, as well as the method of specimen preparation required for their use.

scanning electron microscope The scanning electron microscope uses an electron beam to provide a detailed picture of the outlines of the surface.

Where is calcium stored?

smooth endoplasmic reticulum In addition to storing calcium, the smooth ER also plays a role in detoxification and lipid synthesis.

After their synthesis, proteins are modified and sorted by __________ located in the cell's __________. An example of such a modification is __________. Hint: Proteins are modified after they have been synthesized.

the Golgi apparatus; cytoplasm; adding a phosphate group Proteins are synthesized on ribosomes on the rough endoplasmic reticulum, and then taken by a transport vesicle to the Golgi apparatus in the cell's cytoplasm. After incorporation into the Golgi apparatus, the protein may be modified by adding phosphate groups or altering its carbohydrate portions. It is then removed from the Golgi apparatus by a transport protein or incorporated into the plasma membrane of another organelle. After their synthesis, proteins are modified and sorted by the Golgi apparatus located in the cell's cytoplasm. An example of such a modification is adding a phosphate group.

The term resolving power refers to _____. Hint: Consider what "resolve" means.

the clarity of the image in showing two objects as separate Resolving power is the ability to see two points or objects as separate.

To enter or leave any cell, substances must pass through _____. Hint: Consider the name of the structure that surrounds a cell.

the plasma membrane The plasma membrane defines the boundary of the cell.

Choose the letter that indicates the organelle that contains most of a cell's DNA.

C. nucleus The nucleus contains most of a 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.

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.

Describe the pathway of the protein hormone insulin from its gene to its export from a cell of your pancreas.

An mRNA molecule is transcribed from the gene for insulin and moves into the cytosol. There it joins with a ribosome that becomes attached to the outside of the rough ER (a bound ribosome). The ribosome produces a polypeptide that is threaded into the ER compartment. The polypeptide folds up and may be modified within the ER. It is then packaged into a transport vesicle. The vesicle joins with a Golgi sac, and the protein may be further modified during its journey through the Golgi apparatus. A transport vesicle pinches off from the "shipping" face of the Golgi and fuses with the plasma membrane, secreting insulin from the cell.

Endosymbiosis is the internalization of one species by a host species. According to the endosymbiotic hypothesis, internalized prokaryotes eventually evolved into eukaryotic 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.

Which of the following developments might have contributed to mitochondria becoming endosymbionts in eukaryotic cells? Hint: Organisms survive by adapting.

the increasing availability of atmospheric oxygen As Earth's atmosphere became increasingly oxygen-rich, cells had a survival advantage if they could benefit from an endosymbiont that could use oxygen to release energy. This is the role of mitochondria in eukaryotic cells.

In plants, chlorophyll molecules are located within sacs called __________, which in turn are suspended in the __________ of the __________. Hint: The question concerns the structure of the chloroplast.

thylakoid; stroma; chloroplast The inner membrane of the chloroplast contains a thick fluid called the stroma. Within this, a network of sacs called thylakoids is suspended. These sacs are interconnected and sometimes stacked like poker chips. In plants, chlorophyll molecules are located within sacs called thylakoid, which in turn are suspended in the stroma of the chloroplast.

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.

Transcription is the process by which a DNA template is used for the manufacture of several different types of RNA.

transcription Transcription is the process by which a DNA template is used for the manufacture of several different types of RNA.

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.

In what ways do the internal membranes of a eukaryotic cell contribute to the functioning of the cell?

Different conditions and conflicting processes can occur simultaneously within separate, membrane-enclosed compartments. Also, there is increased area for membrane-attached enzymes that carry out metabolic processes.

Which of these is the double membrane that encloses the nucleus?

E. nuclear envelope This is the nuclear envelope.

_____ are surface appendages that allow a bacterium to stick to a surface.

Fimbriae Fimbriae enable bacterial cells to stick to a surface.

Which of the following is part of the endomembrane system? Hint: The endomembrane system manufactures, processes, and transports lipids and proteins.

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.

Can you identify the functions of the parts of an animal cell? Lysosome

Lysosomes break down macro-molecules using digestive enzymes.

In which of the following ways do lysosomes work within animal cells? Hint: Recall the chemicals that lysosomes contain.

Lysosomes fuse with food vacuoles, digest food, and release nutrients into the cytosol.

Eukaryotic Cells and the Process of Endosymbiosis Step #2

Oxygen-metabolizing bacterium begins to be engulfed by ancestral cell.

Eukaryotic Cells and the Process of Endosymbiosis Step #3

Oxygen-metabolizing bacterium is full engulfed in the cell.

Tour of a Plant Cell -- Organelle Functions Plant Cell Wall

Plant Cell Wall: Strong, protective structure made from cellulose fibrils.

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.

Can you identify the functions of the parts of an animal cell? Ribosome

Ribosomes with with mRNA to synthesize proteins.

Can you identify the functions of the parts of an animal cell? Smooth Endoplasmic Reticulum (ER)

Smooth Endoplasmic Reticulum (ER) is the site of lipid synthesis.

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? Hint: Plant cells have a feature that makes them less flexible than animal cells.

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.

Describe the structure of the plasma membrane of an animal cell. What would be found directly inside and outside the membrane?

The plasma membrane is a phospholipid bilayer with the hydrophilic heads facing the aqueous environment on both sides and the hydrophobic fatty acid tails mingling in the center of the membrane. Proteins are embedded in and attached to this membrane. Microfilaments form a three-dimensional network just inside the plasma membrane. The extracellular matrix outside the membrane is composed largely of glycoproteins, which may be attached to membrane proteins called integrins. Integrins can transmit information from the ECM to microfilaments on the other side of the membrane.

Men with primary ciliary dyskinesia (PCD) have recurrent respiratory tract infections and immotile sperm. What is the cause of these symptoms? Hint: Recall the role of microtubules.

a lack of dynein proteins In PCD, dynein, a motor protein, is lacking. Dynein is attached to the outer microtubules in eukaryotic cilia and flagella. Without it, the structures cannot bend. And without bending, cilia lining the trachea (windpipe) cannot sweep out mucus and debris, and sperm cannot travel to the ovum to fertilize it.

Which cellular organelle is required for photosynthesis to occur in eukaryotic cells? Hint: Consider the organelle that contains photosynthetic pigments.

chloroplast Chloroplasts contain the green pigment chlorophyll and enzymes and other molecules that function in the photosynthetic production of food.

The function of the chloroplast is to _____. Hint: Consider the pigments found within chloroplasts.

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.

What feature of the mitochondrion enhances cellular respiration? Hint: Cellular respiration depends on proteins embedded within a membrane.

cristae Cristae is the term for the extensively folded inner mitochondrial membrane. The folding increases the surface area of the membrane, allowing more proteins to be embedded and thus enhancing the ability of the mitochondrion to produce ATP in cellular respiration.

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).

What changes would you expect to see in the liver cells of someone suffering from chronic alcoholism?

large amounts of endoplasmic reticulum; elevated levels of detoxifying enzymes The smooth endoplasmic reticulum (SER) of liver cells contains enzymes that are involved in alcohol metabolism. With increased alcohol consumption, the amount of SER increases, as does its content of detoxifying enzymes.

A white blood cell is 12-15 µm (microns) in diameter. If you wished to count the white blood cells in a blood sample, which type of microscope would you choose?

light microscope Most plant and animal cells can be observed with a light microscope. This level of magnification is sufficient for visualizing a field of cells that are as large as white blood cells.

Which of the following organelles is found only in animal cells and NOT in most plant cells?

lysosome Lysosomes are membrane-bound sacs containing digestive enzymes that are found only in animal cells. Contractile vacuoles, which keep water and waste products flowing into and out of the cell, perform a similar digestive function in plant cells.

Which organelle plays a role in intracellular digestion?

lysosome The prefix "lyso-" means decomposition.

Which of the following is the correct pairing of a microscopic structure and its approximate size? Hint: Study Figure 4.1E.

mitochondrion: 1 µm Mitochondria are cellular organelles that are about 1 µm in diameter. They fit inside cells, which can be as large as 100 µm.

Which of the following is characteristic of prokaryotic cells but NOT eukaryotic cells? Hint: Prokaryotic cells are simpler than eukaryotic cells.

nucleoid The nucleoid is the region where DNA is located in prokaryotic cells, which lack membrane-bound organelles. DNA in eukaryotic cells is found in the nucleus, which is enclosed by a phospholipid bilayer membrane.

Ribosomal subunits are manufactured by the _____.

nucleolus Ribosomes are manufactured by the nucleolus.

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? Hint: Recall the structure with projections, docking stations, and channels in the animation.

plasma membrane The plasma membrane surrounds the cell and regulates the movement of materials into and out of the cell.

Pancreatic cells produce large amounts of protein. About how many ribosomes would you expect there to be in a pancreatic cell? Hint: Ribosomes are small but very numerous within protein-producing cells.

several million There are several million ribosomes in cells, such as the cells in the pancreas that produce digestive enzymes.

Which listed tissue type would you expect to contain a large proportion of anchoring junctions? Hint: Consider the function of anchoring junctions.

skin Anchoring junctions are most plentiful in tissue that will be stretched or stressed. Skin undergoes both stretching and stress as part of normal wear-and-tear.

Where are lipids made in the cell? Hint: This organelle is not involved in making proteins.

smooth endoplasmic reticulum (ER) The smooth ER makes lipids.

The plasma membrane fits into which of the four general function categories defined in your test? Hint: The plasma membrane provides a boundary between the cell and the outside world.

support, movement, and communication The plasma membrane regulates traffic into and out of the cell. As such, it is an important structure for cell communication with the external environment.

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.

TRUE or FALSE: Animal cells have mitochondria; plant cells have chloroplasts. Explain your answer, and describe the functions of these organelles.

Part TRUE, part FALSE. All animal and plant cells have mitochondria; plant cells do have chloroplasts, but animal cells do not. Both organelles process energy. A mitochondrion converts chemical energy (such as in sugar molecules) to another form of chemical energy (ATP). This process provides eukaryotic cells with ATP needed for cellular work. A chloroplast converts light energy to chemical energy (sugar molecules). These sugar molecules may then provide a plant cell's mitochondria with a source of energy. Or they may be stored in the plant body and passed to animals that eat plants or each other.

Eukaryotic Cells and the Process of Endosymbiosis Step #4

Photosynthetic prokaryote begins to be engulfed by the ancestral cell.

Eukaryotic Cells and the Process of Endosymbiosis Step #5

Photosynthetic prokaryote is full engulfed, resulting in eukaryotic cell with organelles.

Lysosomal storage diseases are rare in the general population. Why? Hint: Recall what happens to a person with such a disease.

Such diseases are usually fatal in early childhood. Lysosomal storage diseases result from the absence of key digestive enzymes normally present in lysosomes. Without these enzymes, undigested material builds up and interferes with the cell's function. The damage is so extensive that most people with such disorders die at a very early age.

The genes for actin are said to be highly conserved. What does this mean? Hint: White blood cells and amoebae exhibit the same type of creeping movement.

The actin gene is similar across many species. The term refers to the similarity of the actin gene in many species over evolutionary time.

Which of the following is the most likely consequence for a cell lacking functional lysosomes? Hint: Consider the "housekeeping" function of 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.

What do the rough endoplasmic reticulum, Golgi apparatus, vacuoles, and lysosomes have in common? Hint: These structures are all members of one of the four main functional compartments of the cell.

They are constructed of a similar type of membrane. Each of these organelles is a member of the endomembrane system and is constructed of the same type of membrane: a phospholipid bilayer.

A transport vesicle within a cell can contain which of the following? Hint: Be as inclusive as possible in your answer.

a newly made glycoprotein, as well as the glycoprotein with its attached phosphate groups Transport vesicles are used for two export functions. First, a protein is exported from the rough endoplasmic reticulum after its manufacture, to the Golgi apparatus, where it will be modified for export from the cell via the cell membrane. Such a modification can include the addition of phosphate groups. (Some proteins will remain within the cell.)

In which cell would you find the most rough ER? a. pancreatic cell that secretes digestive enzymes b. ovarian cell that produces estrogen (a steroid hormone) c. muscle cell in the thigh of a long-distance runner d. white blood cell that engulfs bacteria

a. pancreatic cell that secretes digestive enzymes

Which of the following is one of the major components of the plasma membrane of a plant cell? a. phospholipids b. cellulose fibers c. collagen fibers d. pectins

a. phospholipids

Polypeptides are assembled from _____.

amino acids Proteins are composed of amino acid monomers.

The internal skeleton of a cell is composed of _____. Hint: The cytoskeleton is an internal support system for the cell, which also functions in cell motility.

microtubules, intermediate filaments, and microfilaments These three types of fibers make up the cytoskeleton.

Imagine that you fill a basketball with as many ping pong balls as possible. The volume of the basketball is __________ the total volumes of all the ping pong balls. The surface area of the basketball is __________ than the total surface areas of all the ping pong balls.

approximately equal to; less than Because the ping pong balls fit into the basketball, they have about the same volume as the basketball. However, the total surface area of all the ping balls will be much greater than the surface area of the basketball. This is a similar problem to the one illustrated in Figure 4.2A. Imagine that you fill a basketball with as many ping pong balls as possible. The volume of the basketball is approximately equal to the total volumes of all the ping pong balls. The surface area of the basketball is less than than the total surface areas of all the ping pong balls.

The cells of an ant and an elephant are, on average, the same small size; an elephant just has more of them. What is the main advantage of small cell size? (Explain your reasoning.) a. A small cell has a larger plasma membrane surface area than does a large cell. b. Small cells can better take up sufficient nutrients and oxygen to service their cell volume. c. It takes less energy to make an organism out of small cells. d. Small cells require less oxygen than do large cells.

b. Small cells can better take up sufficient nutrients and oxygen to service their cell volume. Small cells have a greater ratio of surface area to volume.

In which cell would you find the most smooth ER? a. pancreatic cell that secretes digestive enzymes b. ovarian cell that produces estrogen (a steroid hormone) c. muscle cell in the thigh of a long-distance runner d. white blood cell that engulfs bacteria

b. ovarian cell that produces estrogen (a steroid hormone)

Which of the following clues would tell you whether a cell is prokaryotic or eukaryotic? a. the presence or absence of a rigid cell wall b. whether or not the cell is partitioned by internal membranes c. the presence or absence of ribosomes d. both b and c are important clues

b. whether or not the cell is partitioned by internal membranes

_____ is/are identical in structure to centrioles.

basal bodies Basal bodies and centrioles have identical structures.

Peroxisomes are organelles that are involved in the _____. Hint: Peroxisomes are not part of the endomembrane system, but they are included within the functional category.

breakdown of fatty acids Peroxisomes break down fatty acids for fuel, and they are involved in the detoxification of alcohol and other harmful substances.

In which cell would you find the most mitochondria? a. pancreatic cell that secretes digestive enzymes b. ovarian cell that produces estrogen (a steroid hormone) c. muscle cell in the thigh of a long-distance runner d. white blood cell that engulfs bacteria

c. muscle cell in the thigh of a long-distance runner

The ultrastructure of a chloroplast is best studied using a: a. light microscope. b. scanning electron microscope. c. transmission electron microscope. d. light microscope and fluorescent dyes.

c. transmission electron microscope

Which of the following is NOT an example of an organelle found within an animal cell? Hint: Consider the organelles found in animal cells versus other organisms.

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.

In which cell would you find the most lysosomes? a. pancreatic cell that secretes digestive enzymes b. ovarian cell that produces estrogen (a steroid hormone) c. muscle cell in the thigh of a long-distance runner d. white blood cell that engulfs bacteria

d. white blood cell that engulfs bacteria

What changes would you expect to see in the liver cells of someone suffering from chronic alcoholism? Hint: Consider which organelle functions to break down substances such as alcohol.

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.

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 __________. Hint: Consider which of these are components of the cytoskeleton.

microtubules Microtubules are cytoskeletal components, and the shape of a cell is determined by its cytoskeleton.

Where is the genetic information of the cell stored? Hint: Genetic information is encoded in DNA. Think about where you saw DNA in the animation.

nucleus DNA is the genetic information of the cell, and it is stored in the nucleus.

Digestive cells produce and secrete many enzymes that break down ingested food. These cells have a large number of ribosomes __________. Hint: Consider where the proteins that are exported from the cell are produced.

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.

Structures found within a eukaryotic cell and performing specific tasks are collectively termed __________. Hint: Many of these structures are surrounded by their own membranes.

organelles These "little organs" perform a variety of functions, including protein production, energy processing, and breakdown of various molecules.

You, suddenly grown very small because you drank too much TinyMe, are standing between two cells in the trunk of the oak tree behind your apartment. Your feet are stuck in __________. After you free your feet, what is the first barrier that you must cross to enter any of the surrounding cells? Hint: The cell wall is made of more than one layer, and two cells are separated by a layer of a polysaccharide.

pectin; primary cell wall The sticky polysaccharide between cells in plants is pectin, used to thicken jams and jellies. The primary cell wall is the most external part of the cell wall, and the strong secondary cell wall in wood lies next to the plasma membrane. (Of course, you could always slog ahead to find a plasmodesma to enter the cell). Your feet are stuck in pectin. After you free your feet, the first barrier that you must cross to enter any of the surrounding cells is the primary cell wall.

You have identified a new organism. It has ribosomes, chromosomes, a cell wall, and plasmodesmata. This new organism is most likely a(n) __________.

plant Plant cells have cell walls that contain plasmodesmata, which are cytoplasmic channels that connect adjacent cells. They also have ribosomes and chromosomes. You have identified a new organism. It has ribosomes, chromosomes, a cell wall, and plasmodesmata. This new organism is most likely a plant.

Chloroplasts are found in __________. Hint: Consider the function of chloroplasts and what organisms are able to carry out that process.

plant cells and some protists Chloroplasts are lens-shaped organelles found in leaves and other green organs of plants and photosynthetic protists.

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.

What is the function of a bacterium's capsule?

protection A bacterium's capsule has a protective role.

If you wished to clearly observe the organelles inside of a white blood cell, which type of microscope would you choose? Examine Figure 4.1A-C to see which type of microscope is most appropriate for visualizing internal structures of the cells.

transmission electron microscope This type of microscope allows you to view internal structures of living cells.

When you hear the terms contractile, digestive, storage, pigment and poisonous, which of the following organelles comes to mind? Hint: This organelle has a similar role to that of the lysosome.

vacuole Vacuoles perform all of the listed roles, depending on the type of cell they are in. In plants and fungi, vacuoles perform a digestive function. In some protists, contractile vacuoles circulate water throughout the organism. Protein storage vacuoles in plant seeds, pigment vacuoles in flower petals, and vacuoles containing poisonous substances to ward off animals, are other examples.

Which of the following clues would tell you whether a cell is prokaryotic or eukaryotic? Hint: Prokaryotic cells are simpler in structure than eukaryotic cells.

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.