LSXL7C LaunchPad Week 1

signaling cell; responding cell; receptor protein

A ______ expresses a gene or genes that direct production of the signaling molecule, and the ______ expresses a gene or genes that direct production of the ______. a. responding cell; signaling cell; receptor protein b. responding cell; receptor protein; signal protein c. signaling molecule; responding cell; signaling cell d. signaling cell; responding cell; receptor protein

false

A cell can only respond to signals from other cells, not from physical environment. a. true b. false

True

A cell in a chick embryo is tested to determine whether it is a stem cell of some kind. These tests find: 1. The SR receptor is present 2. DIV genes are on 3. The DIFF (skin) genes are blocked 4. TF of the neural pathway is in the cytoplasm 5. Transducer 2 of the skin pathway is not phosphorylated Based on these results, the transcription factor of the Skin pathway is in the cytoplasm. a. False b. True

connective tissue

A pathologist is carrying out an autopsy. Upon opening the chest cavity, the pathologist sees a thick, fibrous tissue surrounding the heart. This is likely: a. connective tissue b. epithelial tissue c. neural tissue d. muscle tissue

nonpolar; pass through

A receptor that is inside the cell would require a ______ signal molecule that can ______ the plasma membrane. a. nonpolar; pass through b. polar; bind to c. nonpolar; bind to d. polar; pass through

a receptor kinase

A researcher is using a small molecule inhibitor that prevents phosphorylation as a tool to manipulate a signaling pathway. What is the most likely target of this small molecule inhibitor? a. a G protein 𝛂 subunit b. a phosphatase c. a G protein-coupled receptor d. a receptor kinase e. a ligand-gated ion channel

DIV genes, ID genes, DET genes

A stem cell is fate determined once is has received the Self Renewal signal. As result, which genes are newly expressed? (Check all that apply). a. DIV genes b. SR genes c. ID genes d. DET genes e. DIFF (neural) genes f. DIFF (skin) genes

The more molecules that share the responsibility of passing the signal to activate the effector the more quickly and efficiently the message can spread.

After a signal binds to a signal receptor, the next step is transduction. Why is the signal transduction step necessary? a. Transmission of the signal through multiple relay molecules before activating an effort is not efficient. b. The more molecules that share the responsibility of passing the signal to activate the effector the more quickly and efficiently the message can spread. c. The signal transduction pathway is not necessary since the signal can directly activate the effector. d. The efficiency increases when less molecules share the responsibility of moving the signal from one molecule to the next to activate the effector.

a collection of cells that lines cavities or outside surfaces

An epithelial tissue is defined as: a. a few cells embedded into an extensive extracellular matrix b. a collection of contractile cells c. a network of cells that use chemical communication d. a collection of cells that lines cavities or outside surfaces

false

As cells differentiate, they lose their ability to become other cell types because they delete subsets of genes. a. false b. true

cell adhesion molecules found in cell junctions.

Cadherins are: a. cell adhesion molecules found in cell junctions. b. proteins that provide a pathway for molecules to move between cells. c. proteins involved in attachment of cells to the extracellular matrix. d. proteins involved in attachment of cells to the basal lamina.

both intermediate filaments and microfilaments

Cadherins bind to which type of cytoskeleton element(s)? a. microtubules only b. microfilaments only c. both intermediate filaments and microfilaments d. intermediate filaments only

gene regulation

Cells differentiate through: a. the cell cycle b. growth c. timing d. gene regulation

undergo irreversible repression

Cellular differentiation progressively restricts cell fate because the unexpressed genes in the cell: (select all that apply) a. accumulate point mutations b. become more densely packed with nucleosomes c. undergo irreversible repression d. accumulate near the centromeres e. are deleted from the genome

myosin; actin filaments

Contraction of muscles is an example of how the motor protein ______ interacts with the cytoskeletal elements called ______ to produce movement. a. kinesin; microtubules b. myosin; dynein c. actin; dynein d. myosin; actin filaments e. dynein; microtubules

No, these motor proteins are specific to microtubules and cannot move along microfilaments.

Could melanin granules be moved by dynein and kinesin along an actin microfilament? a. Yes, motor proteins all use ATP to cause a conformation change. b. No, these motor proteins are specific to microtubules and cannot move along microfilaments. c. Yes, melanin granules would be moved by these motor proteins along microfilaments.

feature of microtubules.

Dynamic instability is a: a. feature of microtubules and microfilaments. b. feature of microfilaments. c. feature of intermediate filaments. d. feature of microtubules. e. universal feature of the cytoskeleton.

receptors

For multicellularity to develop, there must be a mechanism of signaling among cells in the multicellular organism. Which of the structures in the cell membrane receives signals from the environment or from other cells? a. cadherins b. receptors c. gap junctions d. plasmodesmata

They both allow direct transport of materials between cells.

Gap junctions and plasmodesmata have what feature in common? a. They both are made up pf protein subunits located in the plasma membrane. b. They both allow direct transport of materials between cells. c. They are both found in plant cells. d. They both attach to the cytoskeleton.

paracrine signaling

Growth factors such as platelet-derived growth factor (PDGF ) function in: a. paracrine signaling b. autocrine signaling c. contact-dependent signaling d. endocrine signaling

through integrins

How do cells connect to the extracellular matrix? a. through cadherins b. through gap junctions c. through tight junctions d. through integrins

through a conformational change of the receptor

How does an "activated" receptor transfer information into the cell? a. by altering the ligand-binding site of the receptor b. by decreased phosphorylation of the receptor c. by increased translation of the receptor d. through a conformational change of the receptor

Cadherins in desmosomes would no longer be anchored to intermediate filaments.

If a mutation occurred in the cadherin gene so that the cytoplasmic domain no longer attached to the cytoskeleton, which of the following would occur? a. Cadherins in desmosomes would no longer be anchored to intermediate filaments. b. Cadherins in desmosomes would no longer be anchored to microfilaments. c. Cadherins in hemidesmosomes would no longer be anchored to intermediate filaments. d. Cadherins in adherens junctions would no longer be anchored to microtubules.

toward the plus; kinesin

If the vesicle being carried in the figure (in an animal cell) contains content that is to be excreted from the cell at the plasma membrane, it is probably being transported toward the ______ by the motor protein ______. a. toward the minus; dynein b. toward the minus; kinesin c. toward the plus; dynein d. toward the plus; kinesin

All of these choices are correct.

If two signaling pathways are activated simultaneously: a. one may inhibit the other b. they may inhibit each other c. they may strengthen each other d. All of these choices are correct.

The progenitor cell will become a type 1 cell.

Imagine that there is a loss-of-function mutation in the gene for the Notch receptor in the progenitor cell of C. elegans. How does that mutation affect vulva development? Refer to the figure shown. a. The progenitor cell will become a type 1 cell. b. The type 2 cell will differentiate into a type 1 cell. c. The progenitor cell will become a type 2 cell. d. The progenitor cell will remain a type 2 cell.

receptor activation

In many signaling pathways, once a signaling molecule binds to a receptor, the receptor becomes phosphorylated. This initial phosphorylation step best demonstrates: a. either cellular response or signal transduction. b. termination. c. cellular response. d. receptor activation. e. signal transduction.

intermediate filaments

In skin, the cells of the epidermis connect to the basal lamina through cellular junctions known as hemidesmosomes. Select the cytoskeletal element that helps maintain the integrity of this connection. a. both intermediate microtubules and microfilaments b. intermediate filaments c. microtubules only d. microfilaments only

a signaling molecule that binds to the receptor

In the context of cell signaling, to what does the term ligand refer? a. a signaling molecule that binds to the receptor b. the extracellular domain of a receptor protein c. a type of gated channel d. the proteins activated as part of a signal transduction pathway

ligand H

In the figure shown, there are four ligands (M, H, K, and L) and their corresponding receptors along with four genes (S, T, U, and V), whose activity the receptor controls through signal transduction. The arrows indicate gene activation, the T-bars indicate gene expression. Which ligand acts as a signal resulting in gene U being active and V inactive? a. ligand L b. ligand m c. None of the other answer options is correct. d. ligand K e. ligand H

ligand K

In the figure shown, there are four ligands (M, H, K, and L) and their corresponding receptors along with four genes (S, T, U, and V), whose activity the receptor controls through signal transduction. The arrows indicate gene activation, the T-bars indicate gene expression. Which ligand acts as a signal resulting in gene U being inactive and gene V being active? a. ligand L b. ligand m c. None of the other answer options is correct. d. ligand K e. ligand H

It is going toward the minus.

In the image of a microtubule shown here, the plus and minus ends are labeled. If the motor protein shown is dynein, what can you say about the direction in which the vesicle is being carried? a. The direction cannot be determine from data provided. b. It is going toward the plus. c. It can go in either direction on microtubules. d. It is going toward the minus.

All of these choices are correct.

Intermediate filaments: a. All of these choices are correct. b. play an important role in preventing skin from tearing by shear stress. c. play an important role in maintaining cell shape. d. have a diameter that is larger than a microfilament, but smaller than a microtubule. e. undergo little change in length in comparison to microtubules and microfilaments.

grew better in cell culture containing blood serum containing proteins released by platelets during clotting.

Kohler and Lipton first discovered platelet-derived growth factor (PDGF) by observing that fibroblasts: a. grew better in cell culture containing blood serum containing proteins released by platelets during clotting. b. grew better at the same rate in cell culture containing either blood plasma or serum. c. grew better in cell culture blood plasma without the protein released by platelets.

minus end; dynein

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 center. Assuming that the centrosome is near the cell center, you can predict that these vesicles are moving to the ______ end of microtubules using the motor protein ______. a. minus end; dynein b. plus end; dynein c. minus end; kinesin d. plus end; kinesin

endocrine

Mammalian steroid hormones are signaling molecules that function in which type of cell signaling? a. paracrine b. autocrine c. endocrine d. All of these choices are correct

unicellular eukaryotes.

Many of the signaling pathways used for signaling between cells in complex multicellular organisms first evolved in: a. unicellular prokaryotes. b. complex multicellular prokaryotes. c. unicellular eukaryotes. d. simple multicellular eukaryotes. e. simple multicellular prokaryotes.

repeating actin subunits; a thin double-helix

Microfilaments are composed of ______ in ______ arrangement. a. repeating actin subunits; a thin double-helix b. polymers of actin protein; a hollow tube-like c. polymers of tubulin; a double-helix d. alpha and beta dimer subunits; a double-helix

maintain its size and shape.

Microfilaments help a cell ______. a. separate chromosomes during anaphase of mitosis. b. strengthen the plasma membrane. c. maintain its size and shape.

dynamic; polymerize

Microtubules are ______ because they ______ and depolymerize at their ends. a. unstable; hydrolyze b. dynamic; polymerize c. stable; polymerize d. dynamic; hydrolyze

both plus and minus ends; both plus and minus ends

Microtubules can grow by addition of tubulin dimers to ______, and they can shorten by removal of dimers from ______. a. both plus and minus ends; the minus end b. both plus and minus ends; both plus and minus ends c. the minus end; the plus end d. the plus end; the minus end e. the plus end; both plus and minus ends

alpha-tubulin; beta-tubulin; hollow tube

Microtubules form from dimers of ______ and ______ subunits that polymerize into a ______. a. +tubulin; -tubulin; double helix b. beta-tubulin; gamma-tubulin; beta sheet c. an amino acid; phosphate; double helix d. alpha-tubulin; beta-tubulin; hollow tube

false

Most ligands form covalent bonds with their associated receptors, these complexes are more or less permanent and can only be broken through the hydrolysis of ATP. a. true b. false

All of the choices are correct.

Motor proteins cause movement by: a. All of the choices are correct. b. undergoing a conformational change. c. harnessing energy from ATP. d. binding to the cytoskeleton.

microfilaments

Myosin is a motor protein that associates with: a. microfilaments b. microtubules c. vimentin d. intermediate filaments

Notch is a receptor, and Delta is a signaling molecule.

Notch and Delta are both transmembrane proteins involved in cell communication in the developing nervous system of vertebrate animals. What makes Notch different from Delta? a. Notch is a receptor, and Delta is a signaling molecule. b. Notch is a signaling molecule, and Delta is a receptor. c. Notch is required at higher density than Delta to alter cell fate. d. All of these choices are correct.

the cell does not divide

One example of a cellular response to a signal is the triggering of the cell division. If a mutation occurred in the gene for the signal receptor in this pathway that caused the receptor to reject binding of the signal, what response can be predicted? a. the cell does not divide b. the signal is not produced c. the cell divides repeatedly without the signal

The response of the cell would last longer than it normally would.

Phosphatases are a family of enzymes that remove phosphate groups from a specific proteins; these phosphate groups had been added to the proteins by protein kinases. Vanadate is an inhibitor of phosphatases in eukaryotic cells. What effect would vanadate have on the response of cells to signals received by receptor kinases? a. The response of the cell would last longer than it normally would. b. The response of the cell would be shorter than it normally would. c. The signal would still bind the receptor, so there would be no effect.

ligand H, ligand M, ligand K

Shown are four ligands (M, H, K, and L) and their corresponding receptors along with three genes (U, V, and W), whose activity the receptor controls signal through signal transduction. The arrows indicate gene activation, the T-bars indicate gene repression. If either U or V is required to activate W, which ligands result in W being active? Select all that apply. a. None of the other answer options are correct. b. ligand H c. ligand M d. ligand K e. ligand L

polar; on the surface

Signal molecules that are ______ usually have their corresponding receptor ______ of the cell. a. polar; on the surface b. nonpolar; on the surface c. polar; in the cytoplasm

sequential phosphorylation of proteins in the cytoplasm

Signal transduction in development is often amplified by: a. opening and closing of nuclear pores b. methylation of the target cell's DNA c. sequential phosphorylation of proteins in the cytoplasm d. histone modification in chromosome

an extracellular molecule activates a membrane protein, which in turn activates molecules inside the cell.

Signal transduction is the process by which: a. None of the other answer options are correct. b. an extracellular molecule activates a membrane protein, which in turn activates molecules inside the cell. c. a specific combination of transcription factors determines the development pathway in a cell or group of cell. d. transcription factors bind to cis-regulatory regions of DNA and either activate or repress transcription. e. a single master gene, or signal, activates a series of downstream genes that lead to cell differentiation.

travel by diffusion

Signaling molecules involved in paracrine and autocrine signaling: a. travel by diffusion b. remain attached to the plasma membrane c. travel in the circulatory system

true

Signaling pathways have been conserved in a wide range of organisms. a. true b. false

increased surface are for nutrient absorption.

Structures known as microvilli are associated with: a. increased surface are for nutrient absorption. b. communication between cells. c. adhesion to the extracellular matrix. d. increased rates of cell division.

the presence of the appropriate receptors on the cells of the target tissue or organ.

The ability of a specific tissue or organ to respond to the presence of a hormone is dependent on: a. nothing; all hormones of the body are able to stimulate all cell types because hormones are powerful and nonspecific. b. the location of the tissue or organ with respect to the circulatory path. c. the membrane potential of the cells of the target organ. d. the presence of the appropriate receptors on the cells of the target tissue or organ.

true

The ability of cells to adhere to one another is fundamental to multicellularity. a. false b. true

depolymerization; polymerization; spindle apparatus

The ability of microtubules to undergo rapid ______ and slower ______ is associated with the ability of the ______ to explore the cell and locate chromosomes. a. polymerization; depolymerization; microtubules b. depolymerization; polymerization; spindle apparatus c. synthesis; hydrolysis; microtubules d. synthesis; hydrolysis; cytoskeleton elements

a specialized form of the extracellular matrix found beneath all epithelial tissues.

The basal lamina is: a. an area found beneath all connective tissue that helps them adhere to underlying muscle. b. an area found wherever two different types of tissues meet. c. a specialized form of the extracellular matrix found beneath all epithelial tissues. d. a specialized form of extracellular matrix found only in the skin.

a specialized form of the extracellular matrix found beneath all epithelial tissues.

The basal lamina is: a. an area found beneath all connective tissues that helps them adhere to underlying muscle. b. a specialized form of the extracellular matrix found only in the skin. c. an area found wherever two different types of tissue meet. d. a specialized form of the extracellular matrix found beneath all epithelial tissues.

connective

The extracellular matrix is particularly important for which type of tissue? a. nervous b. connective c. muscle d. epithelial

a network of proteins and polysaccharides outside the cell that play a role in structural support.

The extracellular matrix is: a. a network of proteins found in the cellular membrane that allow for substances to enter the cell. b. a network of proteins and polysaccharides inside the cell that keep organelles in place. c. a network of channel proteins found in the cellular membrane that allow for communication. d. a network of proteins and polysaccharides outside the cell that play a role in structural support.

it can give rise to a complete organism

The fertilized egg is totipotent, which means: a. it can be removed and donated to a surrogate womb. b. it forms the membranes that surround and support the developing embryo. c. it only contains genetic material from the female d. it can give rise to a complete organism e. the Y chromosome does not create interference to the expression of X-linked genes

dimerization of the receptor

The first step following platelet-derived growth factor (PDGF) binding of the receptor is: a. phosphorylation of the receptor b. dimerization of the receptor c. activation of gene expression d. activation of MAP kinase

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

The most likely reason(s) a metastatic tumor cell might lose its connection to the basal lamina would be: a. a change in connexins disrupting gap junctions. b. a change in the cadherin proteins on the cell surface. c. All of the choices are correct. d. a change in the integrin proteins from the cell's surface.

express different genes.

The muscle cells and nerve cells in a mouse look very different and serve very different functions in the mouse's body. These differences exist because the muscle cells and nerve cells in the mouse: a. express different genes. b. copy different genes. c. have different genes. d. use different genetic codes. e. have different chromosomes. f. have different genes.

in that new tubulin or actin subunits are added more quickly.

The plus ends of both microtubules and microfilaments differentiate from the minus ends: a. in that new tubulin or actin subunits are added rather than removed. b. in that new tubulin or actin subunits are added more quickly. c. in that the end that always grows in the direction the cell is moving.

excessive cell division

The presence of excess epidermal growth factor (EGF) receptors can result in: a. normal cell division b. diminished cell division c. excessive cell division

its triple helical structure and bundling.

The strength of collagen come from: a. its ability to bind to polysaccharide molecules. b. its amino acid sequence. c. its triple helical structure and bundling. d. its triple helical structure and bundling, as well as its amino acid sequence.

The addition of a drug that prevents the final kinase from interacting with its target protein in the nucleus.

This figure shows how normal signaling works with Ras protein acting downstream of a receptor kinase. You examine a cell line in which Ras is always activated even in the absence of a signaling molecule. This causes constant activation of the kinases in the MAP kinase pathway. Which condition would be the most likely to turn off this abnormally active signaling pathway? a. This addition of a drug that increases the binding affinity of Ras for MAP kinase enzymes in the cytoplasm. b. The addition of a drug that prevents the final kinase from interacting with its target protein in the nucleus. c. The addition of a drug that prevents the phosphorylation of the receptor kinase. d. The addition of a drug that prevents the dimerization of the receptor kinase.

epithelial tissue

This tissue type can perform absorption or secretion in the body. a. nervous tissue b. epithelial tissue c. connective tissue d. muscle tissue

muscle tissue

This tissue type is made up of cells that can contract. a. connective tissue b. muscle tissue c. epithelial tissue d. nervous tissue

VEGF is a paracrine signaling molecule because it binds to receptors on nearby cells, at the site where new blood vessels are needed.

Vascular endothelial growth factor (VEGF pronounced "Veg-F") is a peptide signaling molecule related to platelet-derived growth factor. VEGF is important in the formation of the circulatory system because its signaling pathway causes the formation of blood vessels in developing embryos during normal development. Tumors also produce and secrete VEGF, causing nearby blood vessels to branch and grow to form new blood vessels that supply these tumors. Given what you know about the different kinds of cell signaling and VEGF, which statements is true? a. VEGF is a paracrine signaling molecule because it binds to receptors on nearby cells, at the site where new blood vessels are needed. b. VEGF is an endocrine-signaling molecule because it is released from platelets into the bloodstream and is carried throughout the body, causing widespread activation of platelet-derived growth factor receptors on cells in a variety of tissues. c. VEGF is an endocrine-signaling molecule because it circulates through the bloodstream inside of platelets.

All of the choices are correct.

What does a ligand-gated channel do? a. All of the choices are correct. b. It allows ions to move across the plasma membrane. c. It opens a channel through the plasma membrane when signal molecules bind. d. It can be closed and restrict ion flow when signal molecules are absent.

It lengthens more slowly than the plus end.

What is the best characterization of the minus end of a dynamic filament? a. It lengthens more slowly than the plus end. b. It lengthens quickly but can also lose its subunits quickly. c. It lengthens more quickly than the plus end. d. It loses subunits quickly.

a change in gene expression

What is the end-result of activating the MAP kinase pathway? a. ion flow b. synthesis of second messenger molecules c. phosphorylation of multiple cytosolic proteins d. a change in gene expression

The response to the signal would persist longer after activation.

What would happen to a signaling pathway if phosphates had reduced levels of function? a. The response to the signal would persist longer after activation. b. The response to the signal would be shorter after activation. c. There would be no change in the persistence of the response to the pathway.

signaling molecule; signal receptor

When cells communicate by the signaling process, one cell produces a ______ that must be received by the ______ on or in the responding cell. a. cell division signal; plasma membrane b. hydrophilic signal; hydrophilic receptor c. nonpolar signal; nonpolar receptor d. signaling molecule; signal receptor e. signaling particle; signal enzyme

They maintain the biconcave shape to maximize gas exchange.

Which best describes a role that microfilaments play in the structure and function of RBC's? a. They anchor and orient the O2-bearing hemoglobin protein molecules. b. They maintain the biconcave shape to maximize gas exchange. c. They provide a track for directing O2 to the proper cellular locations.

receptor activation, signal transduction, response

Which is the correct order for these steps in cell signaling? a. signal transduction, receptor activation, response b. receptor activation, response, signal transduction c. response, signal transduction, termination d. receptor activation, signal transduction, response

oval B

Which lettered item in the figure is similar to the payload on a transport vehicle? a. oval C b. oval E c. oval A d. oval B d. oval D

oval C

Which lettered item in the figure is the motor protein? a. oval C b. oval E c. oval A d. oval B d. oval D

oval E

Which lettered item in the figure represents a tubulin dimer? a. oval C b. oval E c. oval D d. oval A e. oval B

autocrine, paracrine, endocrine

Which of the answer choices correctly lists the types of cellular communication from the shortest to longest distance traveled by the signaling molecule to reach its responding cell? a. autocrine, endocrine, paracrine b. endocrine, paracrine, autocrine c. autocrine, paracrine, endocrine d. paracrine, autocrine, endocrine

All of the choices are correct.

Which of the answer choices is a cellular response to signal transduction? a. a change in the activity of an enzyme b. the release of signaling molecules from the cell c. a change in the proteins found in the cytosol d. All of the choices are correct.

a protein that forms a channel that allows ions to enter the cell when a ligand binds

Which of the answer choices would be considered a cell-surface receptor? a. a protein that acts as an enzyme that attaches phosphate groups to substrates b. a protein that binds a nonpolar steroid hormone and activates transcription c. a protein that causes GDP to be exchanged for GTP in a G protein d. a protein that forms a channel that allows ions to enter the cell when a ligand binds

tight junction

Which of the cell junctions is involved in creating a barrier between cells? a. tight junction b. adherens junction c. desmosome

the EGF ligand

Which of the choices is the diffusible extracellular element in the process of vulval cell differentiation in C. elegans? a. the EGF ligand b. the Notch ligans c. the Notch receptor d. the EGF receptor

individual cells must retain a full range of functions, including reproduction.

Which of the options is not a general requirement for complex multicellular life? a. individual cells must retain a full range of functions, including reproduction. b. cells must participate in a network of genetic interactions that require cell division. c. cell must communicate with one another. d. cells must stick together e. all of the above.

endoderm: multipotent

Which pair of terms correctly matches a cell or group of cells with its ability to differentiate specialized cells? a. fertilized egg: pluripotent b. endoderm: multipotent c. mesoderm: pluripotent d. fertilized egg: multipotent e. ectoderm: totipotent

endocrine

Which signaling system involves the longest distance between release of a signaling molecule and activation of a receptor? a. contact-dependent b. autocrine c. endocrine d. paracrine

Kinesin and dynein move substances along microtubules.

Which statement about intracellular transport is true? a. Kinesin and dynein move substances along microfilaments. b. Kinesin moves substances along microfilaments. c. Kinesin and myosin move substances along microtubules. d. Kinesin and dynein move substances along microtubules.

a receptor kinase

Which type of cell-surface receptor undergoes changes in phosphorylation in response to binding of its ligand? a. a receptor kinase b. a G protein-coupled receptor c. a ligand-gated ion channel d. both the G protein-coupled receptor and the receptor kinase

kinase

Which type of protein adds a phosphate group to another molecule? a. phosphate b. kinase c. phosphorylase d. G protein

plus (+) end growth of microfilaments at the tip of the microvillus but no shrinkage at the minus (-) end

Which would be more likely to cause development of a microvillus on an intestinal epithelial cell? a. plus (+) end growth of microfilaments at the tip of the microvillus but no shrinkage at the minus (-) end b. plus (+) end growth of microfilaments at the tip of the microvillus and shrinkage at the minus (-) end c. minus end growth of microfilaments at the tip of the microvillus and shrinkage at the plus (+) end

Ras activates the MAP kinase signal transduction pathway that regulates cell division.

Why are some mutations of Ras associated with cancer? a. Ras is a type of second messenger. b. Ras binds to growth factor receptors. c. Ras activates the MAP kinase signal transduction pathway that regulates cell division. d. Ras alters ion flow across the cell membrane.

Collagen

______ is a component of the extracellular matrix produced by an animal cell. a. Cadherin b. All of the choices are correct. c. Cellulose d. Collagen