Module 1

Question 1

Chapter 3

Question 2

Given that plant cells have chloroplasts, mitochondria are actually unecessary in plant cells.

Answer 2

False

Question 3

Which statement is true regarding chloroplasts?

Chloroplasts release carbon dioxiode as a waste product.

Unlike mitochondria, chloroplasts only contain an outer (and not an inner) membrane.

Chloroplasts utilize carbon dioxide as a reactant.

Chloroplasts are sites of cellular respiration.

Answer 3

Chloroplasts utilize carbon dioxide as a reactant

Question 4

Imagine that you have two blades of grass. One is from a normal plant, and the other is from a mutant plant that cannot absorb water into its vacuoles. How will the structures of these two blades of grass compare?

Answer 4

The grass blade from the mutant plant will appear limp compared to that from the normal plant

Question 5

Mitochondria and chloroplasts are integral parts of the endomembrane system and are specifically connected to the endoplasmic reticulum.

Answer 5

False

Question 6

During osmosis, water moves down its own concentration gradient. How is it possible to reduce the concentration of a solvent?

Answer 6

When more solutes are dissolved in solvents, the concentration of the solute increases, but per unit volume, the concentration of the solvent decreases.

Question 7

Prokaryotes absorb their nutrients from the environment. However, many prokaryotes have cell walls. What can you conclude from this information?

Answer 7

Cell walls are permeable, allowing nutrients to pass through.

Question 8

In which eukaryotic organelle would you expect to find high levels of the enzymes capable of breaking down proteins and nucleic acids?

Answer 8

Lysosome

Question 9

If you place sterile broth that contains no cells in a bowl out on a table overnight, by morning it will contain a growing population of bacterial cells. According to cell theory, how could this be explained?

Answer 9

The growing population of bacterial cells must have come from other bacteria cells that fell into the broth from the air.

Question 10

Which statement is true regarding chloroplasts?

Unlike mitochondria, chloroplasts only contain an outer (and not an inner) membrane.

Chloroplasts release oxygen as a waste product.

Chloroplasts are sites of cellular respiration.

Chloroplasts utilize oxygen as a reactant.

Answer 10

Chloroplasts release oxygen as a waste product.

Question 11

Mitochondria and chloroplasts both have inner and outer membranes.

Answer 11

True

Question 12

Some broad-spectrum proteases (protein hydrolyzing enzymes) and nucleases (nucleic acid hydrolyzing enzymes) that function in eukaryotic cells have an optimum pH close to 5.0, whereas the cytosol of most cells is closer to pH 7.0. Which part of a eukaryotic cell might you predict to have a low pH suited to maximizing the activity of these enzymes?

Answer 12

Lysosome

Question 13

An amphipathic molecule is one that:

Answer 13

Contains both polar and nonpolar regions.

Question 14

What is the function of the contractile vacuole?

Answer 14

To help single-celled organisms maintain homeostasis in a hypotonic environment.

Question 15

Which of the answer choices would be synthesized on the rough endoplasmic reticulum?

Answer 15

Transmembrane protein receptors

Question 16

Slime molds are studied by biologists because of their ability to change from a diffused state, where individual parts are separated, to a unified slimy mass of protoplasm that forms fruiting bodies that produce spores. According to cell theory, what must be true of slime molds?

Answer 16

The diffused state occurs when slime mold cells separate, and the protoplasm stage occurs when slime mold cells cluster together to form spores.

Question 17

How can lysosomal enzymes that work best at a pH of 5 be fully functional if the pH of the cytoplasm is 7?

Answer 17

Lysosomal enzymes are separated from the cytoplasm by the membrane surrounding the lysosome.

Question 18

What is glycosylation?

Answer 18

The addition of sugars to lipids or proteins

Question 19

The interior region of a phospholipid bilayer is characterized as:

Answer 19

Hydrophobic.

Question 20

In which eukaryotic organelle are various macromolecules broken down?

Answer 20

Lysosome

Question 21

Which statement is true regarding chloroplasts?

Answer 21

Chloroplasts release oxygen as a waste product.

Question 22

Slime molds are studied by biologists because of their ability to change from a diffused state, where individual parts are separated, to a unified slimy mass of protoplasm that forms fruiting bodies that produce spores. According to cell theory, what must be true of slime molds?

Answer 22

The diffused state occurs when slime mold cells separate, and the protoplasm stage occurs when slime mold cells cluster together to form spores.

Question 23

Predict how phospholipids would arrange if they were placed in a nonpolar solution rather than a polar solution like water.

Answer 23

The phospholipid tails would orient toward the solution, and the heads would cluster away from the solution.

Question 24

Similarities between the DNA of certain bacteria and the DNA of both mitochondria and chloroplasts are evidence that these organelles originated as bacteria that were captured by another cell and, over time, evolved to their current function.

Answer 24

True

Question 25

How is a carrier protein different from a channel protein?

Answer 25

Carrier proteins undergo conformational change so that they are open alternately to one side of the membrane or the other.

Question 26

Why is the energy from a molecule of ATP required by the sodium-potassium pump?

Answer 26

It provides the energy required to move sodium and potassium ions against their concentration gradients.

Question 27

Researchers seldom find prokaryotic cells that are greater than 100 micrometers in diameter. Why would the size of prokaryotic cells be restricted?

Answer 27

Prokaryotic cells must absorb all of their nutrients from their environment and therefore require a high surface area to volume ratio.

Question 28

Prokaryotes absorb their nutrients from the environment. However, many prokaryotes have cell walls. What can you conclude from this information?

Answer 28

Cell walls are permeable, allowing nutrients to pass through.

Question 29

Why does active transport of molecules across a membrane require ATP?

Answer 29

An input of energy is needed to drive the movement of molecules from an area of low concentration to one of higher concentration.

Question 30

Mitochondria use a simple sugar called pyruvate and ADP when they function. What do mitochondria produce from those substrates?

Answer 30

ATP and carbon dioxide

Question 31

All of the answer choices are properties of at least some prokaryotic cells except: plasmids. small size. pili. a nucleus. A nucleus

Answer 31

A nucleus

Question 32

Chapter 10

Question 33

Many scientists use a specific type of mouse cell to coat the surface of petri dishes with extracellular matrix proteins. This coating forms a layer on which other kinds of cells, often of different species, can adhere and grow. The mouse cells used to coat petri dishes are likely:

Answer 33

Fibroblasts

Question 34

Metastatic cancer cells have a dynamic actin cytoskeleton associated with their cell membrane. The presence of the membrane cytoskeleton most likely accounts for:

Answer 34

The ability of these cells to move and crawl to new locations in the body.

Question 35

Gap junctions and plasmodesmata have what feature in common?

Answer 35

They both allow direct transport of materials between cells.

Question 36

A patient in a physician's office has a deep cut, and as it is being stitched up, a sample of tissue is taken for testing. Analysis of the tissue reveals it has few cells, surrounded by a large amount of extracellular matrix proteins with some blood vessels, sweat glands, and nerve cells. What kind of tissue is this?

Answer 36

The tissue is most likely dermis and should also have some fibroblasts but few keratinocytes and melanocytes.

Question 37

Many scientists are working to generate organs in vitro. In some cases, cells are seeded onto a "scaffold" shaped like the desired target organ. Such scaffolds are likely composed of extracellular matrix proteins.

Answer 37

True

Question 38

A researcher is assessing the expression of a specific protein in cells. This protein appears as a "web" in the cytoplasm of cells. The protein is likely:

Answer 38

A component of the cytoskeleton.

Question 39

The epidermis contains several layers and receives its nutrients from the dermis by diffusion. What explains why the outermost layers of the epidermis consist of dead cells?

Answer 39

One of the major functions of the epidermis is forming a waterproof barrier. Once that barrier is formed, nutrients cannot pass through it and the cells beyond that layer die.

Question 40

Metastatic cancer cells gain the ability to pass through the basal lamina of blood vessels near the tumor site by expressing specific integrins on their cell surface. Which is the most likely reason that specific integrins are required rather than an overall increase in the expression of integrins?

Answer 40

There are over 20 specific types of collagen, and blood vessel collagen only binds to particular integrins.

Question 41

_____ is a component of the extracellular matrix produced by an animal cell.

Answer 41

Collagen

Question 42

A researcher is studying a population of mutant fibroblasts that fail to flatten and attach to extracellular matrix proteins on a flat surface. This is likely the result of mutations in genes encoding:

Answer 42

Components of cell adhesion

Question 43

Macrophage cells undergo a process called phagocytosis in which material is brought into a cell in the form of membrane vesicles and then transported along microtubules toward the cell center. Assuming that the centrosome is near the cell center, you can predict that these vesicles are moving to the _____ of microtubules using the motor protein _____.

Answer 43

minus end; dynein

Question 44

The natural loss of dead cells from the surface of your skin is a result of:

Answer 44

Breakdown of adherens junctions

Question 45

Gap junctions and plasmodesmata have what feature in common?

Answer 45

They both allow direct transport of materials between cells.

Question 46

The most likely reason(s) a metastatic tumor cell might lose its connection to the basal lamina would be:

Answer 46

A change in the integrin proteins from the cell's surface.

Question 47

_____ is not a cellular function associated with microtubules.

Answer 47

Muscle contraction

Question 48

Cancer can be characterized by:

Answer 48

A mass of rapidly dividing cells called a tumor. Cells with an enhanced ability to adhere to proteins in the basal lamina. Metastasized tumor cells that leave the tumor and invade distant parts of the body.

Question 49

Which answer choice correctly lists components found in the extracellular matrix of animals?

Answer 49

Collagen, laminin, and elastin

Question 50

Which of the cell junctions is involved in creating a barrier between cells?

Answer 50

Tight junction

Question 51

A patient in a physician's office has a deep cut, and as it is being stitched up, a sample of tissue is taken for testing. Analysis of the tissue reveals it has few cells, surrounded by a large amount of extracellular matrix proteins with some blood vessels, sweat glands, and nerve cells. What kind of tissue is this?

Answer 51

The tissue is most likely dermis and should also have some fibroblasts but few keratinocytes and melanocytes.

Question 52

Intermediate filaments:

Answer 52

All of these choices are correct.

Question 53

Myosin is a motor protein that associates with:

Answer 53

Microfilaments.

Question 54

Predict what would happen if an embryonic epidermal cell switched from expressing E-cadherin to expressing N-cadherin.

Answer 54

The cell would leave the epidermis and adhere to neural cells.

Question 55

Which cellular property do red blood cells have that allows them to pass through narrow blood vessels?

Answer 55

A flexible cytoskeleton

Question 56

_____ is not a cellular function of microfilaments.

Answer 56

Movement of motile cilia

Question 57

An epithelial tissue is defined as:

Answer 57

A collection of cells that lines cavities or outside surfaces.

Question 58

Which type of cytoskeletal element is present in animal cells but absent from plant cells?

Answer 58

Intermediate filaments

Question 59

Microvilli are located on the ______ of an intestinal cell.

Answer 59

Apical surface

Question 60

What would you expect to find within connective tissue?

Answer 60

Collagen, fibroblasts, polysaccharides, elastin

Question 61

Many scientists are working to generate organs in vitro. In some cases, cells are seeded onto a "scaffold" shaped like the desired target organ. Such scaffolds are likely composed of extracellular matrix proteins.

Answer 61

True

Question 62

The strength of collagen comes from:

Answer 62

Its triple helical structure and bundling