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Cell Biology > Exam 3 > Flashcards

Exam 3 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Charles Overton (1890s)

A

Membranes are basically a lipid substance

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2
Q

Longmuir (1900s)

A

Lipids are phospholipids

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3
Q

Gorther & Grendel (1925)

A

Forms a lipid bilayer

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4
Q

Davson Danielli (1985)

A

Membranes contain proteins “protein sandwich model” proteins on outside

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5
Q

Robertson (1950s)

A

“Unit membrane” membranes function as an inseparable unit lie, membranes cannot be partial & still be functional

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6
Q

Hydrophobic tails

A

nonpolar

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7
Q

Hydrophilic

A

“polar heads” outside

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8
Q

Fluid Mosaic Model (1972) Singer & Nicholson

A
  1. characteristics of membranes are “two-dimensional fluids” (lipids and proteins flow laterally) composed of:
    - Lipid bilayer: “fluid proteins embedded in the lipid bilayer like pieces of mosaic
  2. membranes are asymmetric the two monolayers are composed of different lipids and proteins:
    - Two “faces”
    - Exoplasmic face (E face): faces “outside”
    - Protoplasmic (P faces): also cytoplasmic face (C face): faces “inside”
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9
Q

Exoplasmic face (E face)

A

faces “outside”

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10
Q

Protoplasmic (P faces)

A

Also cytoplasmic face (C face): faces “inside”

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11
Q

Glycolipid

A

carbohydrate chains “antennae” - receptors sensors - environment

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12
Q

Hydrophobic force

A

holds the bilayer together

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13
Q

Chlorestrol

A

animal cell membranes only never plant cell fluidity

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14
Q

Transmembrane protein

A

all the way through. Many transmembrane proteins are transport proteins that facilitate proteins of chemicals through membrane

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15
Q

Channel proteins

A

small, inorganic molecules (porins, aquaporin) or ions (ion channels) by facilitated diffusion

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16
Q

integral proteins (transmembrane proteins)

A

partially or all the way through

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17
Q

uniport

A

one molecule one direction passing by facilitated diffusion

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18
Q

symport

A

2 molecules, same direction, one passing by facilitated diffusion the other by “piggyback”

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19
Q

antiport

A

2 molecules in opposite directions one passing by facilitated diffusion but generates energy to drive the other by active transport in the other direction

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20
Q

Carrier proteins (transporters permeases)

A

large organic molecules by various mechanisms passing facilitated diffusion or by active transport, except never by ATP hydrolysis

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21
Q

Diffusion

A

sometimes called simple diffusion to distinguish it from facilitated diffusion (later)
- the net, (no energy inherent tendency) movement that results from the random kinetic movement of individual molecules from a region of high to low concentrations

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22
Q

Measuring Diffusion

A

the rate of diffusion is a complex function of:
1. The concentration gradient
2. the “resistance” to flow a complex interaction of such characteristics
2.a) The physical and chemical properties of the medium through which the substance is diffusing (density, visiosity, polarity)
2.b) Molecular weight of the diffusing substance according to Graham’s law rate of diffusion
2.c) Temperature: increases the thermal agitation of all molecules

23
Q

Facilitated Diffusion

A

The membrane protein “facilitated” diffusion through the membrane by opening a “tunnel”

24
Q

Osmosis

A

The diffusion of a solvent through a semi-permeable membrane
- permeable to the solvent (water solvent can pass through) not permeable to the solute (solute cannot pass through) high to low concentration of water

25
Q

solute

A

the molecule that is dissolved

26
Q

solvent

A

the substance that the solute is dissolved in

27
Q

osmotic solute has these characteristics

A
  1. soluble in the solvent
  2. cannot pass through the membrane
28
Q

hypotonic osmotic system

A

water flows into cell

29
Q

isotonic osmotic system

A

no net movement of H2O in and out

30
Q

Hypertonic osmotic system

A

water flows out of the cell

31
Q

components of the cytoskeleton summarized

A
  1. microtubules: largest thickest 25nm in diameter
  2. microfilaments
  3. intermediate filaments
32
Q

(components “associated with the cytoskeleton”) known as “motor proteins” or “ mechanoenzymes”

A

they interact with components of the cytoskeleton (above) to produce cellular motion (ATP hydrolysis –> mechanical energy –> movement)

33
Q

(components “associated with the cytoskeleton”) Associated with microtubules

A
  1. dyneins: movement in cilia and flagella
  2. kinesins: movement in mitotic spindle fibers
34
Q

Dyneins

A

movement in cilia and flagella

35
Q

Kinesins

A

movement in mitotic spindle fibers

36
Q

(components “associated with the cytoskeleton”) Associated with microfilaments

A
  1. myosins: associated with actin in muscle cell contraction
37
Q

Microtubules

A

largest (thickest) elements of the cytoskeleton, 25nm in diameter
- long hollow tubules
- globular protein, tubulin: two versions, alpha and beta, bond together to form alphabeta dimer

38
Q

Microtubules are assembled in the microtubule organizing center (MTOC)

A
  • in animals cells, MTOC is the centrosome
  • in plants cells, MTOC is unknown
  • evidence in MTOC is nuclear envelope
39
Q

MTOC is responsible for organizing

A
  1. centrioles: spindle-shaped bundles of microtubules located in the centrosome
40
Q

centrioles

A

Assemble basal bodies located at the base of every cilium (singular) and flagellum (singular)

41
Q

basal bodies

A

assemble cillia (plural) and flagella (plural)

42
Q

Cilia and flagella

A

essentially the same type of structure, differing:
1. length: cilia are short, flagella are long
2. number: cilia are numerous, flagella only one or two per cell

43
Q

microfilaments

A
  • smallest, thinner 7 nm thick
  • structural support of cell, many cell movements:
  • pseudopods in amoeba –> skeletal muscle contraction
44
Q

alpha-actin

A

in skeletal muscle cells

45
Q

F actin

A

filament formed from 2 chains of g-actin coil around each other

46
Q

G actin

A

globular protein- forms a chain

47
Q

Troponin complex

A

protein with 3 subunits:
- one subunit attaches troponin to the actin filaments
- one subunit attaches troponin to tropomyosin
- one subunit binds to Ca2+

48
Q

Tropomyosin

A

filamentous proteins runs along the outer edge of the F-actin filaments

49
Q

Intermediate filaments

A
  • “Intermediate” in thickness 10nm in diameter
  • consists of various rope like fibrous protein with high tensile strength (resist being pulled apart. ex: tug-a-war
  • main function: enables cell to with stand mechanical stresses when stretched
50
Q

Keratin

A

In epithelial cells of vertebrates especially in skin

51
Q

keratin (fibers)

A

hair, feathers, scales, claws, nails

52
Q

vimentin & desmin

A

in connective tissue cells, muscle cells, & the glial cells of nerve cells

53
Q

Neurofilaments

A

neurons in cytoplasm

54
Q

Nuclear lamins

A

nuclear envelope

Cell Biology (5 decks)

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