cell membranes and transport Flashcards

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1
Q

why is it called the FLUID MOSAIC MODEL?

A

FLUID- VISIONS and INDIVIDUAL PHOSPHOLIPIDS can MOVE position

MOSAIC- embedded with PROTEINS, resulting in a mosaic of components

MODEL- based on SCIENTIFIC EVIDENCE

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2
Q

what do GLYCOPROTEINS act as?

A

RECEPTORS or ANTIGENS in cell RECOGNITION

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3
Q

what does CHOLESTEROL do?

A

makes cell more STABLE

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4
Q

what is the function of the phospholipid bilayer?

A

control the MOVEMENT of substances IN and OUT of the cell. Also to CONTAIN RECEPTORS for other molecules

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5
Q

phosphate heads are…

A

HYDROPHYLLIC so INTERACT with water. They’re SOLUBLE

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6
Q

fatty acid tails are…

A

HYDROPHOBIC so REPEL water and are TUCKED into the inner membrane. They’re INSOLUBLE

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7
Q

what factors affect the permeability of the plasma membrane?

A

HIGH TEMP- increases KINETIC energy meaning phospholipids move more and increases permeability

TOO HIGH TEMP- may DENATURE and DAMAGE membrane

TOO LOW TEMP- ice CRYSTALS may form which PIERCE the cell membrane and increase permeability

ETHANOL and pH

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8
Q

how would the steepness of the concentration gradient affect rates of diffusion?

A

BIGGER DIFFERENCE in concentration causes a QUICKER rate of diffusion

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9
Q

how does lipid solubility affect rate of diffusion?

A

NON POLAR molecules diffuse more EASILY than POLAR molecules because they are SOLUBLE in FATTY ACID TAILS

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10
Q

how does surface area affect rate of diffusion?

A

The GREATER the surface area the FASTER the diffusion can take place. This is because the MORE MOLECULES/IONS can cross the membrane at any one moment.

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11
Q

name 4 factors that affect the rate of diffusion

A

TEMPERTURE, LIPID SOLUBILITY, STEEPNESS OF CONC GRADIENT and SURFACE AREA

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12
Q

what is facilitated diffusion?

A
  • requires a CHANNEL PROTEIN in the cell membrane to transport LARGE, POLAR molecules, charged and water soluble molecules across the membrane.
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13
Q

what is simple diffusion?

A
  • the passive movement of SMALL, NON POLAR lipid soluble molecules such as co2 from an area of HIGH concentration to an area of LOW concentration.
  • molecules move directly THROUGH the phospholipid BILAYER
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14
Q

what is active transport?

A
  • can transport ALL TYPES of molecules through CARRIER PROTEINS from an area of LOW concentration to an area of HIGH concentration.
  • requires ENERGY in the form of ATP.
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15
Q

what is cytosis?

A

a form of active transport where parts of the plasma membrane form INFOLDINGS/OUTFOLDINGS There are two types of cytosis - EXOCYTOSIS + ENDOCYTOSIS

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16
Q

what are the two types of cytosis?

A

EXOCYTOSIS and ENDOCYTOSIS

17
Q

which type of cytosis includes when vesicles FUSE with the surface membrane and SECRETES its contents outside (EXits)

A

EXOCYTOSIS

18
Q

osmosis

A

The NET MOVEMENT of WATER molecules across a SELECTIVELY PERMEABLE membrane from a region of higher water potential to a region of lower water potential.

19
Q

water potential

A

the TENDENCY of water to move IN/OUT of a system

20
Q

what is the water potential of water

A

0kPa

21
Q

does water potential increase or decrease with the addition of a solute?

A

DECREASES

22
Q

solute potential

A

a MEASURE of the REDUCTION in WATER POTENTIAL due to a SOLUTE

23
Q

why does water potential decrease when a solute is present?

A

the water molecules will CLUSTER around the solute

24
Q

HYPOTONIC

A

UNDER concentrated

25
Q

HYPERTONIC

A

OVER concentrated

26
Q

pressure potential

A

PHYSICAL pressure exerted by CELL WALLA by preventing FURTHER UPTAKE of water

27
Q

what’s the equation for water potential

A

solute potential + pressure potential

28
Q
A