Chapter 3 Flashcards

1
Q

Describe the structure of the cell membrane (3)

A

1) 75% Phospholipid bilayer and proteins in a fluid mosaic
- separates ICF from ECF
- polar, hydrophilic head & nonpolar, hydrophobic tail with kinks (unsaturated fatty acids)
2) 5% glycolipids: lipids with sugar molec on the outer membrane surface
3) 20% cholesterol: increases membrane stability and fluidity

interstitial fluid (IF): ECF that surrounds cells

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2
Q

What is the membrane potential (3)?

A
  • more Na+ in the ECF, more K+ in the ICF
  • resting membrane potential: voltage measured in resting state
  • due to movement K+ and large anions trapped inside cell
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3
Q

What does it mean to say that the cell membrane is selectively permeable?

A
  • allows specific substances to pass through
  • passive: small/fat-soluble/nonpolar molecules
  • requires channel proteins to let polar/water-soluble substances into cell
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4
Q

How does the arrangement of the phospholipids help make it selectively permeable?

A

-the small kinks in the phospholipid bilayer due to unsaturated bonds allows small/fat-soluble/nonpolar molecules throgh

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5
Q

Give several functions of the 2 types of proteins in the cell membrane.

A
  1. integral proteins: inserted into the membrane
    - most transmembrane but some protrude from one side only
    - functions: transport proteins (channels and carriers), enzymes, receptors
  2. Peripheral proteins: loosely attached to integral proteins
    - functions: enzymes, cell to cell links
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6
Q

What is glycocalyx (5)

A
  • sugar covering at the cell surface (cell surface markers)
  • lipids and proteins attached with carbs
  • every cell type have different pattern of sugars (ID tag - specific biological markers for cell to cell recognition)
  • allows immune system to recognize self and non self
  • cancerous cells change it continuously
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7
Q

Describe these membrane junctions and where each might be found in the body.

  • Tight junction
  • Desmosome
  • Gap junctions
A

Tight junction: impermeable
-line the digestive tract to prevent digestive organisms and enzymes from seeping through into the blood stream

Desmosome: anchor junctions, reduces chances of cell being torn apart due to force
-abundant in tissues subjected to great mechanical stress such as in the skin & heart muslce

Gap junctions: communicating junctions: allows small molec to pass through
-in electrically excitable tissues such as heart and smooth muscle

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8
Q

What is the function of microvilli? Where are they found?

A
  • increase SA

- found on absorptive cells such as kidney and intestinal cells

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9
Q

What factors determine whether a substance can cross the cell membrane?

A

-whether it is hydrophobic, small, or existence of energy & receptors for active transport

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10
Q

4 types of passive transport

A

diffusion, osmosis, facilitated diffusion (glucose), filtration

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11
Q

4 kinds of diffusion

A
  1. simple diffusion: molecules move from high to low concentration
  2. channel-mediated facilitated diffusion: diffusion of large molecules
  3. carrier-mediated facilitated diffusion: molecules attach onto carriers and changes its shape (ex glucose)
  4. osmosis: movement of H2O
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12
Q

Rate increases or decreases:

  • higher temperature
  • large SA
  • larger diffusion molecule
  • larger diffusion distance
  • larger steepness of gradient
A
  • temperature: higher temp = faster
  • SA: high SA = faster
  • large diffusion distance: slower
  • size of substance: slower
  • steepness of gradient: faster
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13
Q

Osmosis (5)

A

-specific kind of diffusion for water
-tonicity: percentage of salt
(9% salt = 9g salt, 91g water)
-isotonic: when the concentration of water is same and no movement; same concentration of molecules in both ECF and ICF
-either wiggle through bilayer or move through aquaporins
-osmolarity: measure of total concentration of solute particles

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14
Q

What happens to cells in a hypertonic environment? What happens in a hypotonic environment?

A
  • hypertonic: more salt on the outside of the cell
  • water diffuses out, causing the cell to shrivle. water follows salt!
  • hypotonic: water moves into the cell, causing it to swell and lyse
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15
Q

2 active processes

A

-active transport, vesicular transport

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16
Q

2 types of channel/carrier proteins

A
  1. Ligand channel proteins (substances/ligands attach to receptors)
    Ex. H2O binds to receptor, which then becomes a 2nd messanger used for chemical reactions
  2. voltage channel proteins: electrical gradient
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17
Q

Active transport (6)

A
  • ATP required
  • transport against the gradient
  • primary: energy comes from ATP hydrolysis
  • secondary: energy comes from the energy stored in ionic gradients created by primary transport
  • ATP energy changes the shape of transport protein to pump ions across the membrane
  • symporters in same directions, antiporters opposite
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18
Q

3 types of endocytosis

A
  1. pinocytosis: transport of water into cell
  2. receptor-mediated pinocytosis
  3. phagocytosis: engulfs large molecules, later fuses with the lysosome to make a phagosome
19
Q

exocytosis (1) examples (5)

A
  • transport out of cell

- hormone secretion, neurotransmitter release, ejection waste, oil secretion from sebaceous glands, sweat production

20
Q

In diffusion, osmosis and facilitated diffusion, is the movement “down” the gradient or “uphill” against the gradient? Do each of the above processes depend on a concentration or pressure gradient?

A

down, yes

21
Q

the sodium-potassium exchange pump is an example of what kind of transport? Why must ATP be used

A
  • active transport
  • used because pumping Na and K from a low to higher concentration
  • 3 Na out. 2K in
22
Q

why would the sodium potassium exchange pump be shut down in poisoning that damage the cells mitochondria? What would happen to the cell

A

-there is not ATP to draw the energy to drive the Na/K pump. The cell’s electrical gradient would disappear

23
Q

Compared to the inside of the cell what is isotonic? hypertonic and hypotonic solutions? what happens to a cell red blood cell placed in each

A
  • isotonic: same solute concentration as outside
  • hypertonic sol: higher concentration of solute outside the cell; water from cell leaves and shrivels
  • hypotonic: solute concentration inside cell higher; water enters and cell lyse
24
Q

what is hydrostatic pressure and what is osmotic pressure

A
  • Osmotic pressure (OP): force of water due to solute concentration (hi solute = hi OP); sucks
  • hydrostatic pressure (HP): force driving filtration; pushes
25
Q

what is membrane potential. Is it more positive or negative on the inside? what ion is more in the intracellular fluid

A

-more positive on the outside because of higher Na concentrations than K concentrations on the inside

26
Q

The Golgi body receives its products from

A

ER

27
Q

the vesicle pinches off the Golgi apparatus has three destinations. name all three of them

A
  1. Exocytosis: secretion of contents outside the cell
  2. Destroyed by fusion with lysosomes
  3. Fuse and incorporate with the cell membrane
28
Q

Mitochondria (2)

A
  • where cellular respiration occurs
  • has its own nucleus
4 steps:
Glycolysis
Citric Acid Cycle
Pyruvate oxidation
Oxidative phosphorylation
29
Q

ER smooth & rough

A
  • smooth: lipid synthesis & calcium storage

- rough: protein synthesis

30
Q

Golgi apparatus

A
  • determines fate of protein

- modifies lipids and proteins

31
Q

Describe a lysosome and its function.

A

-acidic has digestive enzymes that break down waste

32
Q

how does the Tay-Sachs disease cause damage to the neurons? why is the membrane of the lysosome necessary

A
  • lysosomes lack an enzyme needed to break down specific glycolipids in nerve cell membrane.
  • lysosome swell with indigested lipids, interfering with nervous system functioning
33
Q

What is the function of a peroxisome

A

detoxification

34
Q

what is the endomembrane system and what is its function in a cell. 5 organelles.

A
  • produce, degrade, store, and export biological molecules

- includes the ER, golgi, secretory vesicles, lysosome, nuclear envelope

35
Q

describe the components of the cytoskeleton (3)

A
  • microfilaments: semiflexible actin actively lengthens and elongates to change the shape of the cell and allow them to move
  • intermediate filaments: tetramer fibrils that resist tension (attach to desmosome)
  • microtubules: tubulin radiate from centrosome, determine shape of cell and positioning of organelles
36
Q

what components make up Cilia and flagella

A

-centrioles forming the base of cilia and flagella are called basal bodies

37
Q

give the function of Cilia and flagella

A
  • cilia: moves substances across cell surface

- flagella: propels sperm

38
Q

What cell in the body does not contain a nucleus

A

red blood cells

39
Q

apoptosis

A

-apoptosis: controlled cell death to eliminate unneeded, stressed, or aged cells

40
Q

hyperplasia vs hypertrophy

A

-accelerated cell division
-increase in organ/tissue due to an increase in number of cells
Ex. in anemia, RBC divide at an accelerated rate

-growth of an organ/tissue due to an increase in size of its cells

41
Q

atrophy

A

reduction in size or wasting away of an organ/cell resulting from disease or lack of use

42
Q

In protein synthesis, the flow of information is from the DNA to _______ to proteins

A

RNA

43
Q

What are the 6 functions of membrane proteins?

A
  1. Transport
  2. Receptors for signal transductions
  3. Enzymatic activity
  4. intracellular joining
  5. cell-cell recognition
  6. attachment to the cytoskeleton and the extracellular matrix
44
Q

ER smooth & rough

A
  • smooth: lipid synthesis & calcium storage

- rough: protein synthesis