Chapter 3 - Cell Structures

Question 1

Types of substances that can or cannot move through a cell membrane

Answer 1

Can: nonpolar molecules (fatty acids, vitamins ADEK, steroids), oxygen, carbon dioxide, water
Cannot: ions, polar molecules (polysaccharides, AA, glucose,nucleic acids)

Question 2

Types of membrane proteins

Answer 2

• integral: protein physically embedded in the membrane
• transmembrane: embedded through the membrane (integral)
• : peripheral: associated with the membrane, but not embedded

Question 3

The cell membrane consists of

Answer 3

Cholesterol, phospholipids, sphingolipids, carbohydrates, and proteins

Question 4

Cell plasma membrane (plasmalemma) functions

Answer 4

• physical barrier: separated intracellular fluid and extracellular fluid
• gateway for exchange: regulates exchange between intracellular compartments and interstitial fluid
• communication: signals surrounding cells and senses extracellular environment
• cell structure: anchor cytoskeleton, form tissues

Question 5

Endoplasmic Reticulum (def)

Answer 5

Flat series of membrane layers that specializes in secretion of substances (glands)

Question 6

Rough and Smooth ER (def)

Answer 6

• rough (granular): has ribosomes on the surface for protein synthesis, molecules enter ER and are packed for secretion from the cell (neurotransmitters, hormones; beta cells of pancreas)
• smooth (agranular): no ribosomes, used for sorting of molecules, specializes in lipid synthesis, calcium storage (testes, ovaries)

Question 7

Nucleus (def)

Answer 7

internal, organelle that contains the genetic material for cellular reproduction, consists of a nuclear envelope and nucleolus

Question 8

Mitochondria (def)

Answer 8

The “power house” of the cell; a double-membrane organelle that produces the ATP through oxidative phosphorylation

Question 9

Golgi complex (def)

Answer 9

Set of flat, stacked, membranous sacs that process raw material transported from the ER into finished products; sorts and directs the finished products to their final destination

Question 10

Zymogens (def)

Answer 10

Structures that are produced in an inactive form and are made functional after being cut (insulin)

Question 11

Types of cytoplasmic vesicles

Answer 11

• lysosomes
• peroxisomes
• transport vesicles

Question 12

Lysosome def and characteristics

Answer 12

• contain enzymes that breakdown foreign invaders, other organelles, proteins, CHO, some fats
• serves cell for digestion and secretion
• failure to breakdown glycolipids causes Tay-Sachs

Question 13

Peroxisome (def)

Answer 13

• breakdown fatty acids and amino acids using oxidative enzymes
• produces hydrogen peroxide

Question 14

Transport vesicles (def)

Answer 14

Used in transport and storage of substances

Question 15

Cellular inclusions (def and examples)

Answer 15

• nonmembrane structures within the cytoplasm

* ribosomes, proteasomes, vaults

Question 16

Ribosomes (def)

Answer 16

Granules of RNA and proteins, translate mRNA into proteins

Question 17

Proteasomes (def)

Answer 17

Small protein complex that destroys proteins

Question 18

Vaults (def)

Answer 18

Small complex of RNA and proteins resembling octagonal structures, unknown exact function

Question 19

The protein fibers that compose the cytoskeleton (def and types)

Answer 19

• assists eukaryotic cells in their overall shape, organization, transport, and movement
• microfilaments, intermediate filaments, and microtubules

Question 20

Microfilaments (def)

Answer 20

Mechanical stiffener for microvilli, important in contractile systems (actin and myosin)

Question 21

Microvilli (def)

Answer 21

Stiff projections on the cell surface that increase surface area and are supported by microfilaments

Question 22

Intermediate filaments (def)

Answer 22

Structural support in cells subject to mechanical stress (myosin, keratin)

Question 23

Microtubules (def and examples)

Answer 23

• Maintains cell shape, coordinates complex cellular movement (tubulin)
• centrioles, cilia, flagella

Question 24

Specialized cell junctions

Answer 24

Tight junction, adhering junction, gap junction

Question 25

Tight junction (def)

Answer 25

Prevents passage between cells (occluding junctions)

Question 26

Adhering junction (def)

Answer 26

Strong connection between cells subject to high mechanical stress

Question 27

Gap junctions (def)

Answer 27

Special junctions containing connexons that serve as conduits between cytoplasm of adjoining cells allowing the passage of small molecules