bio chapter 10

Which of the following most accurately describes the structure of cellulose?

A linear polysaccharide made of repeating molecules of glucose attached end to end.

What are the functions of anchoring junctions?

Attach cells to each other. Bond cells to the extracellular matrix.

How do adhesive proteins work?

They are able to connect to receptors on the surfaces of cells. They have sites that bind to polysaccharides and proteins in the extracellular matrix.

Which of the following statements about plasmodesmata is true?

They can be closed, open, or dilated.

What is the function of cadherins?

They create cell-to-cell junctions.

What is the function of structural proteins found in the extracellular matrix (ECM)?

They impart tensile strength and elasticity.

How do animal cells differ from bacterial, fungal, and plant cells?

They secrete an extracellular matrix for support and organization They do not have cell walls for support and organization

The phenomenon of transepithelial transport is facilitated by what type of cell junctions?

Tight junctions

Bone

Tightly bound polypeptides that form stiff fibers

What is the primary function of glycosaminoglycans (GAGs) and proteoglycans in the extracellular matrix?

To provide resistance to compression

Which of the following is the main function of collagen?

To provide tensile strength to the extracellular matrix.

True or false: The primary cell wall is synthesized before the secondary cell wall.

True

Fill in the blank question. In an anchoring junction, cadherin proteins on the interior of the cell are connected by linker proteins to or intermediate filaments of the cytoskeleton. This promotes a more stable interaction between the two cells.

actin

In animals, cell junctions that hold adjacent cells together or attach cells to the extracellular matrix are known as

anchoring junctions

Although they both provide tensile strength and resistance to compression, the extracellular matrix of animals and cell walls of plants differ because the cell walls of plants ______.

are able to prevent osmotic lysis are more rigid are thicker

Anchoring junctions that create cell-to-cell junctions contain proteins called ______.

cadherins

In adherens junctions, proteins called connect cells to each other. In the cytosol, adherens junctions bind to filaments.

cadherins actin

In a desmosome, proteins called connect cells to each other. In the cytosol, desmosomes are connected to filaments.

cadherins intermediate

The extracellular domains of two cadherin proteins, each in adjacent cells, bind to each other to promote cell-to-cell adhesion. This binding requires the presence of ion

calcium

In plants and animals, cells are linked to one another by ______.

cell junctions

In plants, the structure that provides mechanical support, maintains cell shape, and prevents osmotic lysis is the

cell wall

The main macromolecule of the plant cell wall is the polysaccharide

cellulose

The transmembrane proteins that form tight junctions are called

claudin occludin

Although they are both structural proteins, provides tensile strength, whereas provides elasticity to the body parts in which they are found.

collagen, elastin

Tight junctions are mechanically weaker than anchoring junctions because they do not have strong connections with the

cytoskeleton

Plasmodesmata can change the size of their opening between closed, open and states.

dilated

Anchoring junctions attach adjacent animal cells to each other and to the matrix.

extracellular

True or false: The extracellular matrix of animals tends to be thicker, stronger, and more rigid than the cell walls of plants.

false

In animals, junctions form channels between cells that allow cells to communicate with one another.

gap

Polysaccharides

gel like

In vertebrates, the most abundant polysaccharides in the extracellular matrix are ______.

glycosaminoglycans

The most abundant types of polysaccharides in the extracellular matrix of vertebrates are the

glycosaminoglycans

The four types of anchoring junctions in humans are adherens junctions, desmosomes,

hemidesmosomes focal

The two types of anchoring junctions that connect cells to the extracellular matrix are

hemidesmosomes focal adhesions

Anchoring junctions are animal cell junctions that ______.

hold adjacent cells together or attach cells to the extracellular matrix

Cell adhesion molecules that do not require Ca2+ to function are called

integrins

The metastasis (or spread) of cancer cells can be associated with abnormalities in ______.

integrins

What cell adhesion molecules are composed of two nonidentical subunits?

integrins

Select the two types of cell adhesion molecules (CAMs).

integrins cadherins

The structure of a tight junction is best described as ______.

interlaced strands of protein

Passage of through gap junctions allows the coordinated contraction of cardiac muscle cells.

ions

Specialized structures within a higher organism that link cells together are called cell

junctions

Abnormalities in integrins are often associated with ______.

metastasis of cancer cells

The middle lamella of plant cell walls is rich with ______.

negatively charged polysaccharides

Select the membrane proteins found in tight junctions.

occludin claudin

In a plasmodesma, the ______ of one cell is continuous with that of another cell.

plasma membrane

The blue arrow in this figure points to a type of cell junction called ______, and which is found in ______.

plasmodesma; plants

This micrograph is obtained from plant tissue. The labels point to cell junctions called

plasmodesmata

Proteins are a major component of the extracellular matrix in animals. The second major molecular components are

polysaccharides

The cell wall of plants is composed of two parts: a flexible layer called the cell wall that is synthesized first, and a thicker layer called the cell wall that consists of successive layers.

primary secondary

What component of a plant cell wall is synthesized first?

primary cell wall

Proteoglycans are produced when glycosaminoglycans (GAGs) are linked to ______.

proteins

In the extracellular matrix, most glycosaminoglycans (GAGs) are linked to core proteins, forming large molecules called

proteoglycans

Cadherins are cell adhesion molecules that connect cells to each other. This is accomplished by the binding of a cadherin in one cell to ______.

the same type of cadherin in an adjacent cell

Tight junctions are not mechanically strong because ______.

they do not have strong connections with the cytoskeleton

This figure depicts a type of cell junction called

tight

What type of cell junction is made of membrane proteins called occludin and claudin that form interlaced strands in the plasma membrane?

tight junction

Which of the following structures prevent material from passing in between adjacent cells of animals?

tight junction

The functions of the various proteins in the extracellular matrix are:

to connect cells to components of the extracellular matrix to provide tensile strength to organize the extracellular matrix to provide elasticity

Abnormalities in cadherins and integrins can affect signal pathways within the cell.

transduction

True or false: Cadherins and integrins play roles in cell communication.

true

Glycosaminoglycans and proteoglycans form a gel-like component in the extracellular matrix because their negative charges attract ______.

water

In mammals, collagen is the most prevalent protein, making up what percentage of the total protein mass?

25%

Which of the following anchoring junctions bind to actin filaments in the cytoskeleton?

Adherens junctions Focal adhesions

Which of the following are examples of anchoring junctions found in animals?

Adherens junctions Hemidesmosomes Focal adhesions Desmosomes

What type of animals have cadherin genes?

Both vertebrates and invertebrates

What cell adhesion molecules require calcium ions for binding?

Cadherins

A newly discovered role of the extracellular matrix (ECM) is , which allows cells of multicellular organisms to sense their environment.

Cell

The cells of multicellular organisms can sense their environment through what function of the extracellular matrix (ECM)?

Cell signaling

What is the major component of plant cell walls?

Cellulose

Which of the following is a polysaccharide composed of repeating molecules of glucose attached end to end?

Cellulose

As we age, synthesis of the protein decreases. This causes a loosening of the network of fibers, resulting in wrinkles and sagging of the skin.

Collagen

As we age, the synthesis of a certain protein decreases, causing a loosening of the fibers and resulting in wrinkles and sagging of the skin. What is the name of this protein?

Collagen

Lining of the capillaries

Collagen proteins that form a meshwork pattern

Which of the following statements about adherens junctions are true?

Contain cadherins Bind to actin filaments in the cytosol

What process requires gap junctions?

Contraction of cardiac muscle cells

Which type of anchoring junction contains cadherins that connect cells to each other and to intermediate filaments in the cytosol?

Desmosome

Consider an E-cadherin protein in a particular cell. This protein will most likely bind an ______.

E-cadherin protein in an adjacent cell

Which of the following are structural proteins in the extracellular matrix?

Elastin Collagen

True or false: Cadherin genes are only found in humans.

False

What type of cell junctions is shown in the provided micrograph?

Gap junctions

What types of cell junctions are found in animals?

Gap junctions Anchoring junctions Tight junctions

Tight junctions perform several important roles including what?

Help maintain the polarity of intestinal cells Prevent leakage of materials across cell layers Prevent microbes from entering the body

What is the function of the middle lamella in plants?

Holds adjacent cell walls together

______ are cell adhesion molecules which form connections between the cells and the extracellular matrix.

Integrins

Which of the following body parts contains collagen fibers with loosely bound alpha chains?

Intestines Lungs

What are the functions of the plant cell wall?

It prevents osmotic lysis. It maintains cell shape. It provides mechanical support. It helps to determine the direction of cell growth.

In the extracellular matrix of animals, what adhesive protein organizes the components of the basal lamina?

Laminin

Which of the following proteins are adhesive proteins of the extracellular matrix that bind components of the ECM to each other and/or to cell surfaces?

Laminin Fibronectin

Lining of the intestines

Loosely bound polypeptides that form flexible fibers

What are the functions of the extracellular matrix in animals?

Participates in cell signaling Provides strength Provides structural support Organizes cells and binds body parts together

What is the main component of the middle lamella in plants?

Pectins

What type of macromolecule found within the extracellular matrix (ECM) helps resist compression of the ECM?

Polysaccharides

What macromolecules found in the extracellular matrix (ECM) provide strength and elasticity?

Proteins

Which of the following types of molecules are chiefly responsible for connecting components of the extracellular matrix (ECM) to cells, organizing the ECM, and providing it with tensile strength and elasticity?

Proteins

What do gap junctions do in animals?

Provide passageways for intercellular transport

The primary and secondary cell walls surrounding plant cells are named based upon what?

The timing of synthesis; the primary cell wall is synthesized first.

How do glycosaminoglycans (GAGs) protect cells from compression?

Their negative charge allows them to attract water, giving the extracellular matrix a gel-like quality.