Chapter 3 Study Skills: Key Terms

Helpfulness: 0
Set Details Share
Page to share:
Embed this setcancel
COPY
code changes based on your size selection
Size:
X
Show:
1

Cell Theory

The cell is the basic structural and functional unit of life; how well an entire organism functions is dependent on individual and combined activities of all of its cells

Bottom line: everything is in service to the cell

2

Principle of Complementarity (of the Cell)

Functions of the cells are dictated by the shapes of the cells and their specific subcellular structures

3

Mitosis

Primary process of (nuclear) cell division in which one parent cell produces two identical daughter cells with the same number of chromosomes as the parent cell

4

Plasma Membrane

Forms the outer boundary of the cell, acts as a selectively permeable barrier; generates electrochemical gradient; cell-cell communication/recognition, cell signaling

5

Cytoplasm

intracellular fluid that is packed with organelles

6

Organelles

Small structures that perform specific functions

7

Nucleus

Organelle that houses DNA and controls cellular activities

8

Extracellular materials

substances contributing to body mass that are found outside the cells

i.e.: interstitial fluid, blood plasma, cerebral spinal fluid, serous fluids and other cellular secretions (mucus, saliva, etc.)

9

Interstitial fluid

Fluid in tissues that bathes all of our cells

10

Selective Permeability

Determines the manner in which substances enter or exit the cell

11

Fluid-Mosaic Model

Depicts the plasma membrane as an exceedingly thin structure composed of a double layer (bilayer) of lipid molecules with protein molecules dispersed in it

12

Integral Proteins

Proteins that are firmly inserted into the lipid bilayer; most are transmembrane proteins that span the entire membrane and protrude from both sides;

Main functions: transport proteins (channels, pores, carriers, pumps), enzymes, and receptors

13

Passive Transport Processes

Transport Processes in which no energy is required

14

Active Transport Processes

Transport Processes in which energy (ATP) is required

15

Diffusion

Tendency of ions or molecules (solutes) to move from an area of higher concentration to an area of lower concentration (moving down along their concentration gradients)

16

Simple diffusion

"Unassisted" diffusion; small, non-charged, lipid-soluble (hydrophobic) molecules diffuse directly through phospholipid bilayer

i.e. gases (oxygen, carbon dioxide), fat-soluble vitamins

17

Facilitated Diffusion

"Assisted" diffusion; large, charged, lipid-insoluble (hydrophilic) molecules are transported passively down their concentration gradient via carrier-mediated or channel mediated channel diffusion

i.e.: glucose, amino acids, ions

18

Carrier-Mediated Facility Diffusion

Molecules (usually sugars or amino acids) bind to protein carriers (transmembrane proteins), which causes the carrier to change shape and move the molecule across the membrane in the process

19

Channel-Mediated Facilitated Diffusion

Molecules move through water-filled channels (transmembrane proteins), which are selective based on size and charge of molecules (often ions)

20

Leakage Channels

Transport channels that are always open

21

Gated Channels

Channels that have gates and opening/closing controlled by chemical or electrical signals

22

Osmosis

Movement of water across a selectively permeable membrane

23

Aquaporins

Channels through which water is diffused during osmosis

24

Hydrostatic Pressure

pressure exerted by the fluid against the walls of blood vessels; caused by the movement of water during osmosis

25

Osmotic Pressure

The force opposing hydrostatic pressure; caused by the movement of water during osmosis

26

Colloid Osmotic Pressure

Force opposing the hydrostatic pressure created by colloids (large non-diffusable proteins) such as albumin (primary blood protein); caused by the movement of water during osmosis

27

Tonicity

The ability of a solution to change the shape or "tone" of cells by altering the cells' internal water volume based on the concentration of a solute

28

Isotonic Solution

Equal concentration of solute inside and outside of the cell, so the cell volume stays the same

29

Hypertonic solution

Greater concentration of solute outside of the cell than inside of the cell, so the cell volume decreases

Medical term: crenation

30

Hypotonic Solution

Lesser concentration of solute outside of the cell than inside of the cell, so the cell volume increases

Medical term: lyse/lysis

31

Solute Pumps

Active transporters that move solutes (usually ions) from an area of low concentration to an area of high concentration (against their concentration gradient)

32

Primary Active Transport

Energy from hydrolysis of ATP causes change in shape of transport protein, which causes solutes (ions) bound to the protein to be pumped across the membrane

33

Sodium-Potassium Pump

Enzyme (called Na+-K+ ATPase); Maintains the sodium (Na+) and potassium (K+) concentration gradients by pumping 3 Na+ molecules out of the cell and 2 K+ molecules into the cell (against their concentration gradients)

Located in all plasma membranes, but especially active in excitable cells (nerves/muscles)

34

Secondary Active Transport

Driven by single ATP-powered pumps (i.e.: Sodium-Potassium Pumps); the movement of sodium against its concentration gradient stores energy, and as sodium is diffused back across the plasma membrane, other substances (i.e.: glucose) are driven into the cell against their concentration gradients

35

Vesicular Transport

Involves the transport of large particles, macromolecules, and fluids across the membrane through vesicles (bubble-like membranous sacs)

36

Endocytosis

Vesicular transport into the cell; A portion of the plasma membrane folds in and encloses a substance within a vesicle to be taken into the cell for destruction or ransport and release from opposite side of the cell

37

Phagocytosis

"Cell-eating"; Membrane projections form and flow around solid particles that are being engulfed, forming a vesicle which is pulled into the cell

Used only by macrophages and certain white blood cells (called phagocytes)

38

Pinocytosis

"Cell-drinking"; fluid-base endocytosis, in which infolding plasma membrane surrounds a very small volume of extracellular fluid containing dissolved molecules

39

Exocytosis

Process in which material is ejected from the cell; Substance being ejected is enclosed within a secretory vesicle, which bind with plasma membrane proteins to release the substance to the exterior of the cell; Usually activated by cell-surface signals or changes in membrane voltage

i.e.: hormones, neurotransmitters, mucus, cellular wastes

40

Membrane Potential/Voltage

The difference in electrical charge between two points, and can be measured; only occurs at the membrane surface

41

Resting Membrane Potential (RMP)

At rest, membrane voltages range from -50 to -100 millivolts (mV) in different cells (inside of the cell is more negative relative to the outside of the cell)

42

Mitochondria

Powerhouse of the cell, providing most of the ATP supply

43

Ribosomes

Small, dark-staining granules composed of proteins/RNAs

44

Free Ribosomes

Ribosomes that float freely in the cytosol

Main function: make soluble proteins that function in the cytosol, as well as those imported into the mitochondria and some other organelles

45

Membrane-Bound Ribosomes

Ribosomes that are attached to membranes, forming the rough endoplasmic reticulum

Main function: synthesize proteins destined either for incorporation into cell membranes or lysosomes, or for export from the cell

46

Endoplasmic Reticulum

Extensive system of interconnected tubes and parallel membranes enclosing fluid-filled cavities (cisterns); continuous with the outer nuclear membrane and accounts for about half of the cell's membranes

47

Rough Endoplasmic Reticulum (Rough ER)

Surface is studded with ribosomes that synthesize proteins

Main functions: ribosomal protein synthesis, membrane synthesis, housing the active sites for enzymes that catalyze lipid synthesis

48

Smooth Endoplasmic Reticulum (Smooth ER)

Continuous with the rough ER, consists of tubules arranged in a looping network with enzymes integrated into its membranes

Main functions: metabolize lipids, synthesize cholesterols/phospholipids/lipid components of lipoproteins/steroid-based hormones, absorb, synthesize, and transport fats, detoxify drugs/cancer-causing chemicals, break down stored glycogen to form free glucose

49

Golgi Apparatus

Consists of stacked and flattened membranous sacs associated with swarms of tiny membranous vesicles

Main function: principle "traffic director" for cellular proteins; modify, concentrate, and package the proteins and lipids made at the rough ER and destined for export from the cell

50

Peroxisomes

Spherical membranous sacs containing a variety of powerful enzymes

51

Oxidases

Enzymes contained within peroxisomes

Main function: use O2 to detoxify harmful substances; neutralize free radicals (highly reactive chemicals with unpaired elections that can scramble the structure of biological molecules)

52

Catalases

Enzymes contained within peroxisomes

Main function: pair with oxidases to neutralize free radicals; oxidases convert them to hydrogen peroxide, which catalases then convert to water

53

Lysosomes

Spherical membranous organelles containing activated digestive enzyme

Main function: digestion of almost all kinds of biological molecules (i.e.: ingested bacteria/viruses/toxins, stressed/dead cells, worn-out/nonfunctional organelles); breakdown of bone to release calcium ions into blood, metabolic functions like glycogen breakdown/release

54

Endomembrane System

System of organelles that work together mainly to 1) produce/degrade/store/export biological molecules, and 2) degrade potentially harmful substances

55

Cytoskeleton

"cell skeleton"; elaborate network of rods running through the cytosol and hundreds of accessory proteins that link these rods to other cell structures

Main function: act as the cell's "bones", "muscles", and "ligaments" by supporting cellular structures and providing machinery to generate various cellular movements

56

Microfilaments

Thinnest elements of the cytoskeleton; semiflexible strands of the protein actin

Involved in cell motility (movement) or changes in cell shape; work with other proteins to generate contractile forces in the cell; forms the cleavage furrow that pinches one cell into two during cell division

57

Intermediate Filaments

Tough, insoluble protein fibers that resemble woven ropes; composed of tetramer (4) fibrils

Most stable and permanent of cytoskeletal elements, have high tensile strength

Act as internal guy-wires to resist pulling forces exerted on the cell

58

Microtubules

Hollow tubes made of spherical protein subunits called tubulin

Determine the overall shape of the cell and the distribution of cellular organelles

59

Centrosome

Cell center

Acts as microtubule organization center

60

Centrioles

Small, barrel-shaped organelles oriented at right angles to each other that are contained within the granular-looking matrix of the centrosome

Form the bases of cilia and flagella

61

Cillia

Whip-like, motile cellular extensions that occur on the exposed surfaces of certain cells that are formed by centrioles

Main function: moving substances in one direction across cell surfaces

62

Flagella

Projections formed by centrioles that are substantially longer than cilia; only flagellated cell in the human body is the sperm cell

63

Basal Bodies

Centrioles forming the bases of cilia and flagella

64

Microvilli

Minute, fingerlike extensions of the plasma membrane that project from an exposed cell surface to increase the plasma membrane's surface area tremendously

Most often found on the surface of absorptive cells (i.e.: intestinal and kidney tubule cells)

65

Multinucleate

"multiple nuclei"; presence of multiple nuclei usually indicates that a larger-than-usual cytoplasmal mass must be regulated

66

Anucleate

"Without a nucleus"; anucleate cells cannot reproduce because they cannot produce mRNA to make proteins

67

Nuclear Envelope

Double-membrane barrier separated by fluid-filled space that binds the nucleus

68

Nuclear Pores

Various points where the nuclear envelope is punctuated; regulate entry and exit of molecules (e.g.: mRNAs) and large particles into and out of the nucleus

69

Nucleoli

Dark-staining spherical bodies where the ribosomal subunits are assembled

70

Chromatin

System of bumpy threads weaving through the nucleoplasm; primary units are nucleosomes

Composed of DNA, histone proteins, and RNA chains

71

Chromosomes

Short, barlike bodies formed by chromatin threads coiling and condensing enormously in preparation for cell division

Compactness prevents the delicate chromatin strands from tangling and breaking during cell division