Chapter 3 Cells

Question 1

cell membrane

Answer 1

• encloses the cell; thin an flexible; consists of lipids and proteins, with few carbohydrates
• selectively permeable or semipermeable (only certain substances can enter or leave a cell
• regulates movement of substances in and out of the cell and it the site of much biological activity
• enable the cell to survive and to interact with other cells; use a molecular communication process called signal transduction

Question 2

nucleus

Answer 2

houses the genetic material (DNA)

-enclosed in a doubled-layered nuclear envelope

Question 3

cytoplasm

Answer 3

fills out the cell

Question 4

phospholipid bilayer

Answer 4

• double layer framework of a cell membrane

- each molecule includes a phosphate group and two fatty acids bound to a glycerol molecule.

Question 5

Cholesterol molecules

Answer 5

rigid structures stabilizes the cell

Question 6

ion channels

Answer 6

• in the phospholipid bilayer that allows only particular ions to enter or leave the cell.
• are specific for calcium (CA+2) sodium (Na+2) potassium (K+) or chloride (C1-)

Question 7

Cellar Adhesion Molecule (CAM)

Answer 7

guides a cell’s interactions with other cells.

Question 8

Proteins that have portions that extend from the outer surface of the cell membrane mark the cell as a part of particular tissue or organ belonging to a particular person

Answer 8

• identification of “self”
• important for functioning of the immune system
• many of these proteins that extend from the outsides of cells are attached to carbohydrates, forming glycoproteins.

Question 9

Cytoplasm

Answer 9

• gel like material that includes the cellular organelles
• it makes up most of a cell’s volume
• contains cytosol, protein rods and tubules (microfilament and microtubules) that form a framework, or cytoskeleton

Question 10

cytosol

Answer 10

cytoplasm contains vast and complex networks of membranes and organelles suspended in the more-liquid cytosol

Question 11

cytoskeleton

Answer 11

aka- cell skeleton

the framework (proteins rods, tubules, (microfilaments and microtubules)

Question 12

organelles (5)

Answer 12

ribosomes
endoplasmic reticulum (smooth and rough)
vesicles
Golgi apparatus

Question 13

Ribosomes

Answer 13

tiny, spherical structures composed of proteins and RNA.

• provide structural support and enzymatic activity to link amino acids to synthesize proteins.
• scattered in the cytoplasm and bound to the ER
• polysomes enable a cell to quickly manufacture proteins required in large amounts.

Question 14

polysomes

Answer 14

• clusters of ribosomes in the cytoplasm

- enable a cell to quickly manufacture proteins required in large amounts.

Question 15

endoplasmic reticulum (ER)

Answer 15

• complex organelle composed of membrane-bound, flattened sacs, cylinders and fluid-filled, bubble like sacs called vesicles
• membranous parts are interconnected and communicate with the cell membrane, the nuclear envelop and other organelles
• winds from the nucleus out toward the cell membrane
• provides a vast tubular network that transports molecules from one cell to another
• participates in the synthesis of proteins and lipid molecules (molecules may leave the cell as secretions or be used within the cell for producing new ER or cell membrane as the cell grows
• acts as quality control center for the cell.
• forming protein to start to fold into the shape necessary for is function
• identify and dismantle a misfolded proteins
• studded with ribosomes, which give the ER a textured appearance.
• proteins move through ER tubules to another organelle, the Golgi Apparatus, for further processing

Question 16

Rough ER

Answer 16

parts of the ER with ribosomes

Question 17

smooth ER

Answer 17

as the ER nears the cell membrane, it becomes more cylindrical and ribosomes become sparse and then are no longer associated with ER.

• along the SER are enzymes that are important in lipid synthesis, absorption of fats from the digestive tract, and the metabolism of drugs
• cells that break down drugs and alcohol, such as liver cells have extensive networks of smooth ER

Question 18

Vesicles

Answer 18

membranous sacs that store or transport substances within a cell and between cells

Question 19

large vesicles

Answer 19

contain mostly water form when a part of the cell membrane folds inward and pinches off bringing solid material from outside the cell into the cytoplasm

Question 20

small vesicles

Answer 20

shuttle material from the rough ER to the golgi apparatus as part of the process of secretion

Question 21

golgi apparatus

Answer 21

stack of 5-8 flattened membranous sacs that resemble pancakes

refines, packages and transports proteins synthesized on ribosomes associated with ER.

a cell can have several

proteins arrive at the Golgi apparatus enclosed in vesicles composed of membraned from the ER sugar molecules were attached to some of the proteins in the ER, forming glycoproteins. these vesicles fuse with the membrane at the inner most end of the Golgi apparatus, which is specialized to receive glycoproteins. glycoproteins pass layer to layer through the Golgi stacks, they are modified chemically. when the glycoproteins reach the outer most layer, they are packaged in bits of Golgi membrane which bud off and form transport vesicles. a transport vesicle may then move to and fuse with the cell membrane releasing its contents to the outside secretion

Question 22

mitochondria

Answer 22

elongated, fluid-filled sacs that house most of the biochemical reactions that extract energy from the nutrients in digested food.

• oblong, but vary somewhat in size and shape
• move slowly through the cytoplasm and reproduce by dividing
• inner layer (cristae); increases the surface area
• connected to the cristae are enzymes that control some of the chemical reactions that release energy from nutrients in a process called cellular respiration
• store this energy in the chemical bonds of adenosine triphosphate
• cell can easily use energy stored as ATP.
• contain small amounts of their DNA

Question 23

lysomes

Answer 23

tiny membranous scat that house enzymes that dismantle debris

• bud off sections of the Golgi apparatus
• maintain the acidic pH that enables the enzymes to function; as well as shield the rest of the cell from the acidic conditions.

Question 24

perozisomes

Answer 24

membranous sacs that are abundant in liver and kidney cells

• house enzymes that catalyze a variety of biochemical reactions
• break down hydrogen peroxide (a by product of metabolism) and fatty acids, and detoxify alcohol

Question 25

microfilaments

Answer 25

- thin, thread like strands in the cytoplasm - they form in the cytoskeleton and are also part of certain structures (centrosomes, cilia, and flagella) that have specialized activities - tiny rods of the proteins actin - form meshworks or bundles, and provide cell motility(movement)

Question 26

microtubules

Answer 26

- thin, thread like strands in the cytoplasm - they form in the cytoskeleton and are also part of certain structures (centrosomes, cilia, and flagella) that have specialized activities - long slender tubes with diameters two or three times those of microfilaments - composed of molecules of the globular protein tubulin, attached in a spiral to form a long tube.

Question 27

Centrosome

Answer 27

structure near a Golgi apparatus and the nucleus | - consists of two cylinders called centrioles

Question 28

centrioles

Answer 28

lie at right angles to each other -composed of nine groups of three microtubules during mitosis, the centrioles distribute chromosomes to newly forming cells

Question 29

cilia

Answer 29

- motile structures that extend from the surfaces of certain cells - composed of microtubules similar to centrioles but with two additional microtubules in the center - move coordinated to and fro manner,so that rows of them beat in succession, producing a wave of motions

Question 30

flagella

Answer 30

- motile structures that extend from the surfaces of certain cells - composed of microtubules similar to centrioles but with two additional microtubules in the center - much longer the cilia and usually a cell has only one - moves in an undulating wave, which begins at its base - tail of a sperm cell is a flagellum that enables the cell to "swim"

Question 31

nuclear envelope

Answer 31

consists of inner and outer lipid bilayer membranes protein lined channels called nuclear pores that allow certain molecules to exit the nucleolus is large enough to let out the RNA molecules that carry genes messages but not large enough to let out DNA it's self

Question 32

nucloplasm

Answer 32

nucleus fluid which nucleolus and chromatin are suspended

Question 33

nucleolus

Answer 33

small, dense body composed of largely RNA and proteins | ribosomes form in the nucleus and then migrate through nuclear pores to cytoplasm

Question 34

chromatin

Answer 34

consist of loosely coiled givers of DNA and proteins. - chromatin fivers coil tightly when the cell begins to divide - the condense to form the individual chromosomes - unwinds locally to permit access to the information in certain genes