Chapter 10

Question 1

Multicellular

Answer 1

Organisms composed of more than one cell

Question 2

Multicellular organisms

Answer 2

Organisms composed of more than one cell
Main benefit from the division of labor
Larger genomes = larger proteomes

Question 3

Additional proteins used for:

Answer 3

1. Cell communication
2. Arrangement and attachment of cells
3. Cell specialization

Question 4

Extracellular Matrix and Cell Walls

Answer 4

Extracellular Matrix (ECM)
Network of material secreted from the cells forming a complex meshwork outside of cells

Question 5

Major component of certain parts of plants and animals:

Answer 5

Bone and cartilage of animals
Woody parts of plants

Question 6

The major macromolecules of the ECM

Answer 6

proteins and polysaccharides

Question 7

Extracellular Matrix and Cell Walls - Compoents

Answer 7

Animal cells secrete ECM that helps to support and organize cells
Major macromolecules are proteins and polysaccharides
Proteins form large fibers
Polysaccharides give a gel-like character

Question 8

Extracellular Matrix and Cell Walls - Compoents
Important roles

Answer 8

Strength and structural support
Tissue organization
Cell signaling

Question 9

Proteins of ECM
Adhesive

Answer 9

Fibronectin and laminin
Adhere ECM components together and to the cell surface

Question 10

Proteins of ECM
Structural

Answer 10

Collagen provides tensile strength
Main protein found in bone, cartilage, tendon, skin
Elastin provides elasticity
Expands and returns to original shape

Question 11

elastin

Answer 11

A protein that makes up elastic fibers in the extracellular matrix of animals.

Question 12

glycosaminoglycan (GAG)

Answer 12

The most abundant type of polysaccharide in the extracellular matrix (ECM) of animals, consisting of repeating disaccharide units that give a gel-like character to the ECM.

Question 13

proteoglycan

Answer 13

A long, linear core protein with many GAGs attached to it; found in the ECM.

Question 14

Polysaccharides in animal ECM

Answer 14

After proteins, 2nd major component of ECM
In vertebrates, the most abundant are glycosaminoglycans (GAGs)
1. Long, unbranched polysaccharides with a repeating disaccharide unit
2. Highly negatively charge attracts positive ions and water

Question 15

Glycosaminoglycans in animal ECM

Answer 15

GAGs and proteoglycans resist compression
Form gel-like component
Two GAG examples:
Chondroitin sulfate – cartilage
Hyaluronic acid – found in skin, eyes, joint fluid
Chitin important in ECM for invertebrates
Exoskeleton of arthropods

Question 16

chitin

Answer 16

A tough, nitrogen-containing polysaccharide that forms the external skeleton of many insects and crustaceans and is found in the cell walls of fungi.

Question 17

cellulose

Answer 17

The main macromolecule of the cell wall of plants and many algae; a linear polymer made of thousands of glucose monomers.

Question 18

Plant cell walls

Answer 18

Protective cell wall outside the plasma membrane
Rigidity for mechanical support
Maintenance of cell shape
Direction of cell growth
Usually stronger, thicker and more rigid than ECM than in animals

Question 19

The cell wall of plants are composed of a primary cell wall and secondary cell wall

Answer 19

1. The primary cell wall is thin and flexible. It contains cellulose microfibrils in a meshwork pattern, along with other components shown on the far right.
2. The secondary cell wall is made in successive layers. Each layer contains strong cellulose microfibrils in parallel arrays. The direction of cellulose microfibrils in each layer is varied, as shown on the right.

Question 20

Cell Junctions

Answer 20

Adhere cells to each other and to the ECM
Animals cells have a more varied group of junctions
In plants, cellular organization is different because of the rigid cell wall

Question 21

Anchoring Junctions (Animal Cells)

Answer 21

Attach cells to each other and to the ECM
Rely on cell adhesion molecules (CAMs)
Cadherin
Integrin

Question 22

Cadherins

Answer 22

Extracellular domain of two cadherins, each in adjacent cells, bind to each other to promote cell-to-cell adhesion
Inside the cell, linker proteins connect cadherins to the cytoskeleton
By expressing only certain types of cadherins, each cell will only bind to other expressing same type

Question 23

Integrins

Answer 23

Group of cell-surface receptor proteins
1. 2nd type of CAMs
2. Creates connections between cells and ECM
3. Do not require Ca2+ to function
4. Extracellular domain to bind to ECM
5. Intracellular domain for binding to cytoskeleton

Question 24

Tight Junctions in Animals

Answer 24

Also known as occluding junctions
Forms tight seal between adjacent cells
Prevents ECM from leaking between cells
Tight junctions:
Made by occludin and claudin
Bind to each to form tight seal
Not mechanically strong, not bound to cytoskeleton

Question 25

adherens junction

Answer 25

A mechanically strong type of cell junction between animal cells that is organized into bands. The cells are connected to each other via cadherins, and the cadherins are linked to actin filaments on the inside of the cells.

Question 26

gap junction

Answer 26

A type of junction between animal cells that provides a passageway for intercellular transport.

Question 27

Middle lamella in plants

Answer 27

Plants use additional component of ECM to form cell-to-cell connections
First layer to form when cells dividing
Cement cell walls of adjacent cells together
Middle lamella rich in pectins
Ripening fruit secrete pectinases – this is why ripe fruit becomes soft

Question 28

Middle Lamella in Plants

Answer 28

Plants use additional components of the ECM to form cell-to-cell connections
First layer to form when cells dividing
Middle lamella rich in pectins
Ripening fruit secrete pectinases – this is why ripe fruit becomes soft

Question 29

Plasmodesmata in Plants

Answer 29

Functionally similar to gap junctions
Allow passage of ions and molecules between adjacent cells
Different in that they are open channels where the cell membrane of one cell is continuous with adjacent cell membrane
Desmotubule connects ER membrane of adjacent cells

Question 30

Commom types of cell junctions
Animal
Plants

Answer 30

Animal
1. Anchoring junctions
2. Tight junctions
3. Gap junctions
Plants
1. Middle lamella
2. Plasmodesmata

Question 31

Animal Tissues
Tissue

Answer 31

a group of cells having a similar structure or function

Question 32

Humans have over 200 different cell types that are grouped into a few general categories:

Answer 32

Epithelial - Cells joined together forming continuous sheets to cover or line body surfaces
Connective - Support body or connect tissues
Nervous - Receives, generates and conducts electrical signals
Muscle - Generates force that facilitates movement

Question 33

Organ

Answer 33

Collection of two or more tissues that perform a specific function or set of functions

Question 34

Plant Tissues
1. Dermal Tissue
2. Ground Tissue
3. Vascular Tissue Vascular Tissue

Answer 34

Dermal Tissue - Covering on various plant parts
Ground Tissue - Most of the plant’s body with variety of functions. (Parenchyma, Collenchyma, Sclerenchyma)
Vascular Tissue - Form interconnected conducting vessels for water and nutrients.