Chapter 2 Notes

Question 1

Plasma Membrane

Answer 1

The plasma membrane, sometimes called the cell membrane, forms the outer, limiting barrier separating the internal contents of the cell from the external environment.

Question 2

Cytoplasm

Answer 2

Cytoplasm is a general term for all cellular contents located between the plasma membrane and the nucleus. The three components of the cytoplasm are cytosol (a viscous fluid), inclusions (nonfunctional, temporary structures that store cellular products), and organelles (tiny structures that perform specific cellular functions).

Question 3

Nucleus

Answer 3

The nucleus is the cell’s control center. It controls protein synthesis (production of new proteins), and in so doing, it directs the functional and structural characteristics of the cell

Question 4

Plasma Membrane Structure

Answer 4

Phospholipid bilayer containing cholesterol and proteins (integral and peripheral) and some carbohydrates (externally

Question 5

Plasma Membrane Function

Answer 5

Contains receptors for communication; forms intercellular connections; acts as physical barrier to enclose cell contents; regulates material movement into and out of the cell

Question 6

Cytoplasm Structure

Answer 6

Contains cytosol, a viscous fluid, and inclusions and organelles

Question 7

Cytoplasm Function

Answer 7

Place of many metabolic processes of the cell; stores nutrients and dissolved solutes

Question 8

Cytosol Structure

Answer 8

Viscous fluid medium with dissolved solutes (ions, nutrients, proteins, carbohydrates, lipids, and other small molecules)

Question 9

Cytosol Function

Answer 9

Provides support for organelles; serves as viscous medium through which diffusion occurs

Question 10

Organelles Structure

Answer 10

Membrane-bound and non-membrane-bound structures that have unique functions and activities

Question 11

Organelle Function

Answer 11

Carry out specific metabolic activities of the cell

Question 12

Inclusions Structure

Answer 12

Droplets of melanin, protein, glycogen granules, or lipid; usually non-membrane-bound

Question 13

Inclusions Function

Answer 13

Store materials

Question 14

Nucleus Structure

Answer 14

Surrounded by double membrane nuclear envelope (each membrane is a phospholipid bilayer); contains nucleolus and chromatin

Question 15

Nucleus Function

Answer 15

Acts as cell control center; controls all genetic information (DNA); site of ribosome subunit assembly

Question 16

Nucleur Envelope Structure

Answer 16

Double membrane boundary between cytoplasm and nuclear contents

Question 17

Nucleur Envelope Function

Answer 17

Physical barrier that controls movement of materials between the nucleus and the cytoplasm

Question 18

Nucleur Pore Structure

Answer 18

Openings through the nuclear envelope

Question 19

Nucleur Pore Function

Answer 19

Allow for passage of materials between nucleus and cytoplasm

Question 20

Nucleuolus Structure

Answer 20

Spherical, dark-staining, dense granular region in the nucleus

Question 21

Nucleuolus Function

Answer 21

Synthesizes rRNA and assembles ribosomes in the nucleus

Question 22

Chromatin and chromosomes Structure

Answer 22

Filamentous association of DNA and histone proteins

Question 23

Chromatin and Chromosome Function

Answer 23

Site of genes in the DNA

Question 24

Smooth endoplasmic reticulum (smooth ER) Structure

Answer 24

Interconnected network of membrane tubules and vesicles; no ribosomes

Question 25

Smooth ER Function

Answer 25

Synthesizes lipids; metabolizes carbohydrates; detoxifies drugs, alcohol

Question 26

Rough endoplasmic reticulum (rough ER) Structure

Answer 26

Flattened intracellular network of membrane sacs called cisternae; ribosomes attached on cytoplasmic surface

Question 27

Rough ER Function

Answer 27

Synthesizes proteins for secretion, new proteins for the plasma membrane, and lysosomal enzymes; transports and stores molecules

Question 28

Golgi Apparatus Structure

Answer 28

Stacked series of flattened, smooth membrane sacs with associated transport vesicles (also called shuttle vesicles)

Question 29

Golgi Apparatus Function

Answer 29

Modifies, packages, and sorts newly synthesized proteins for secretion, inclusion in new plasma membrane, or lysosomal enzyme synthesis

Question 30

Lysosomes Structure

Answer 30

Membrane sacs with digestive enzymes

Question 31

Lysosome Function

Answer 31

Digest materials or microbes ingested by the cell; remove old/damaged organelles; self-destruct (autolyze)

Question 32

Peroxisomes Structure

Answer 32

Membrane-enclosed sacs; usually contain large amounts of specific enzymes to break down harmful substances

Question 33

Peroxisome Functions

Answer 33

Convert hydrogen peroxide formed during metabolism to water

Question 34

Mitochondria Structure

Answer 34

Double membrane structures with cristae; fluid matrix contents at center

Question 35

Mitochondria Function

Answer 35

Synthesize most ATP during cellular respiration; “powerhouses of cell”

Question 36

Ribosomes Structure

Answer 36

Dense cytoplasmic granules with two subunits (large and small); may be free in cytoplasm (free ribosomes) or bound to rough ER (bound ribosomes)

Question 37

Ribosomes Function

Answer 37

* Synthesize proteins for: * use in the cell (free ribosomes) * secretion, incorporation into plasma membrane, or lysosomes (bound ribosomes)

Question 38

Cytoskeleton Structure

Answer 38

Organized network of protein filaments or hollow tubules throughout the cell

Question 39

Cytoskeleton Function

Answer 39

Provides structural support; facilitates cytoplasmic streaming, organelle and cellular motility, transport of materials, and chromosomal movement and cell division

Question 40

Microfilaments Structure

Answer 40

Actin protein monomers formed into filaments

Question 41

Microfilaments Function

Answer 41

Maintain cell shape; aid in muscle contraction and intracellular movement; separate dividing cells

Question 42

Intermediate Filaments Structure

Answer 42

Various protein components

Question 43

Intermediate Filaments Function

Answer 43

Provide structural support; stabilize cell junctions

Question 44

Microtubules Structure

Answer 44

Hollow cylinders of tubulin protein; able to lengthen and shorten

Question 45

Microtubules Function

Answer 45

Support cell; hold organelles in place; maintain cell shape and rigidity; direct organelle movement within cell and cell motility as cilia and flagella; move chromosomes at cell division

Question 46

Centrosome Structure

Answer 46

Amorphous region adjacent to nucleus; contains a pair of centrioles

Question 47

Centrosome Function

Answer 47

Organizes microtubules; participates in spindle formation during cell division

Question 48

Centrioles Structure

Answer 48

Paired perpendicular cylindrical bodies; composed of microtubule triplets

Question 49

Centrioles Function

Answer 49

Organize microtubules during cell division for movement of chromosomes

Question 50

Cilia Structure

Answer 50

Short, membrane-attached projections containing microtubules; occur in large numbers on exposed membrane surfaces

Question 51

Cilia Function

Answer 51

Move fluid, mucus, and materials over the cell surface

Question 52

Flagellum Structure

Answer 52

Long, singular membrane extension containing microtubules

Question 53

Flagellum Function

Answer 53

Propels sperm in human male

Question 54

Microvilli Structure

Answer 54

Numerous thin membrane folds projecting from the free cell surface

Question 55

Microvilli Function

Answer 55

Increase membrane surface area for absorption and/or secretion