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Anatomy > Plasma Membrane > Flashcards

Plasma Membrane Flashcards

1
Q

What are the functions of the plasma membrane?

A

form outer boundary and interacts with external environment

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2
Q

What is the plasma membrane composed of?

A

Phospholipid bilayer

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3
Q

What is the extracellular matrix?

A

Space outside of the cell

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4
Q

What is the intracellular matrix?

A

Space inside of the cell

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5
Q

What does it mean for the plasma membrane to be selectively permeable?

A

It allows some substances to cross more easily than others

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6
Q

Describe how the phospholipid bilayer is arranged

A

2 lipid (fat) layers “tail to tail” with protein molecules scattered throughout

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7
Q

Describe the fluid mosaic model

A

The sea: phospholipids
The icebergs: proteins, carbs, cholesterol

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8
Q

What does it mean for phospholipids to be amphipathic and what is the purpose?

A

It has a hydrophilic head and hydrophobic tail, the hydrophilic head faces outwards so hydrophilic molecules are kept out

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9
Q

What does the amount of cholesterol scattered throughout the phospholipids determine?

A

The fluid nature of the membrane

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10
Q

What are the proteins scattered in the lipid bilayer responsible for?

A

The specialized functions of the membrane

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11
Q

In terms of proteins, fill in the blanks: _____ determines _____.

A

structure determines function

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12
Q

Name 4 membrane proteins

A

enzymes
receptor proteins
transport proteins
marker proteins

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13
Q

What do receptor proteins help pass?

A

Hormones or chemical messengers

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13
Q

What do transport proteins help pass?

A

substances that cannot passively diffuse through the lipid bilayer

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14
Q

Name 3 different types of marker proteins and describe them

A

Glycoprotein: sugar group attached to a protein
Glycolipid: sugar group attached to a phospholipid head
Glycoalyx: term given to all glyco-proteins and –lipids that span the cell surface

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15
Q

What are the 4 pathways to cross the plasma membrane?

A

Diffusion through lipid bilayer (lipid soluble)
Membrane channels (protein pores)
Carrier molecules within the membrane (proteins)
Vesicles (endocytosis, exocytosis)

16
Q

What can pass through the membrane?

A

Nonpolar (lipid soluble) molecules
small molecules

17
Q

What cannot pass through the membrane?

A

Polar (water soluble) - passage slowly, some require transport molecules to cross while others are excluded (too large)
Vesicles – transport into the cell through endocytosis
Ions

18
Q

What are the 3 types of movement through the membrane?

A

Simple diffusion
Facilitated diffusion
active transport

19
Q

What is simple diffusion and what are the two types?

A

Requires NO energy
Movement of solutes from an area of higher concentration to lower concentration in solution (down)
Filtration and osmosis

20
Q

What is a concentration or density gradient?

A

difference between two points

21
Q

What is filtration and what does it require?

A

Passive process by which water and solutes are forced through a membrane or capillary wall by fluid or hydrostatic pressure (hp)
Requires a pressure gradient that pushes solute containing fluid (filtrate) from high to low pressure

22
Q

What is osmosis?

A

Diffusion of water (solvent) across a selectively permeable membrane

23
Q

How does water move?

A

an area of low concentration of solute to an area of high concentration of solute

24
Q

What is a hypotonic solution?

A

lower solute concentration outside the cell

25
Q

What is a hypertonic solution?

A

higher solute concentration outside the cell

26
Q

What is an isotonic solution?

A

solute concentration same

27
Q

What does a cell do when placed in a hypotonic solution?

A

lyses (bursts)

28
Q

What does a cell do when placed in a hypertonic solution?

A

crenates (shrink)

29
Q

Describe facilitated diffusion

A

Mediated by transport proteins
Requires NO energy

30
Q

What are 2 ways for facilitated diffusion?

A

A hydrophilic channel
Loosely bind/carry molecules across

31
Q

Give an example of facilitated diffusion?

A

An aquaporin protein channel allowing the passage of water

32
Q

Describe active transport

A

Requires ENERGY (ATP)
Proteins transport substances against concentration gradient or electrical gradient

33
Q

Give an example of active transport

A

Electrogeneic pumps
- Na+/K+ Pump (Pump Na+ out, K+ in)

34
Q

How does passive transport follow concentrations?

A

high to low
down the concentration gradient

35
Q

How does active transport follow concentrations?

A

low to high
against the concentration gradient

36
Q

What are the 2 types of vesicular transport?

A

Endocytosis: take in macromolecules, form new vesicles
Exocytosis: vesicles fuse with cell membrane, expel contents

37
Q

What are the 3 types of endocytosis?

A

Phagocytosis: solids
Pinocytosis: fluids
Receptor-Mediated Endocytosis: Substances bind to specific receptors on cell surface

Anatomy (4 decks)

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