Membrane Structures and Functions Flashcards
1
Q
Phospholipid Bilayer
A
- Made of a bilayer of phospholipids
- Heads are phoshpates (polar, hydrophilic)
- Tails are lipids (non-polar, hydrophobic)
- Hydrophobic portion acts as a barrier to many molecules
*
2
Q
Integral Proteins
A
- Span from inner to outer portion of bilayer
- Can act as channel proteins to transport molecules across bilayer
3
Q
Peripheral Proteins
A
- Inside - help maintain shape or cell motility
- Can also be enzymes and catalyze reactions in the cytoplasm
4
Q
Glycoproteins
A
- Involved in cell recognition (part of immune system)
- Act as receptors in signaling (as with hormones)
5
Q
Cholesterol
A
- Reduces fluidity in plasma membrane, thus increasing stability
6
Q
Carrier Protein
A
- Specific to molecules
- Changes shape slightly to transport
- Down concentration gradient - facilitated diffusion
- Against concentration gradient - active transport
7
Q
Receptor Proteins
A
- Detect hormones to signal changes in cell function
- Involved in other cell and substance recognition (ex. in immune system)
8
Q
Enzymes
A
- Catalytic proteins
- End in -ase
- ex. ATP Synthetase, Maltase
9
Q
Electron Carriers
A
- Seen in photosynthesis and respiration in oxidation/reduction reactions
10
Q
Diffusion
A
- No energy required
- High concentration -> low concentration
- Caused by kinetic energy of particles
- Direction of movement random
11
Q
Diffusion through a membrane (ex. lungs)
A
- The location that supplies and maintains the concentration of particles is called the source
- The location where the substance is continually removed (or changed) is called the sink
- Maintaining the concentration gradient between the two areas is a feature of biological systems
Source = blood oxygen in lungs Sink = respiring cell
12
Q
Osmosis
A
- Diffusion of water through a membrane
13
Q
What molecules pass through the membrane with little resistance?
A
Oxygen, Carbon Dioxide, Water, Lipids (hydrophobic)
14
Q
Facilitated (passive) Transport Across Membranes
A
- Chanel proteins - create a tunnel for large molecules
- Carrier proteins
15
Q
Active Transport Across the Membrane
A
- Against concentration gradient (low to high cocentration)
- Requires energy (ATP, produced in cell respiration)
- Carrier proteins
- Sodium-potassium pump/Hydrogen-proton pump
- Cells are negatively charged on the inside relative to the outside (creates voltage)
16
Q
Exocytosis
A
- The protein is moved through the rER and modified
- A sperical vesicle is formed from the end of the rER with the protein inside
- Vesicle and golgi membranes fuse. The protein is released into the lumen of the golgi apparatus
- The golgi modifies the protein further
- A new vesicle is formed from golgi membrane which then breaks away
- The vesicle migrates to the plasma membrane fuses secretes content. A process called exocytosis.
17
Q
Endocytosis
A
a vesicle is formed by the enfolding of the plasma membrane
3 types: phagocytosis (cellular eating) pinocytosis (cellular drinking) and receptor-mediated endocytosis
18
Q
Membrane Fluidity
A
- Phospohlipid molecules changing places in horizontal plane caused fluid property of membrane
- Cholesterol reduces fluidity
- Unsaturated hydrocarbon tails - kinks, double bonds, fluid
- Saturated hydrocarbon tails - no kinks, no double bonds, viscous
19
Q
Channel Proteins
A
Facilitated (passive) diffiusion
Aquaporins (facilitated diffusion of water)
ion channels (gated channels, open/close in response to stimulus)
20
Q
- Made of a bilayer of phospholipids
- Heads are phoshpates (polar, hydrophilic)
- Tails are lipids (non-polar, hydrophobic)
- Hydrophobic portion acts as a barrier to many molecules
A
Phospholipid Bilayer
21
Q
- Span from inner to outer portion of bilayer
- Can act as channel proteins to transport molecules across bilayer
A
Integral Proteins
22
Q
- Inside - help maintain shape or cell motility
- Can also be enzymes and catalyze reactions in the cytoplasm
A
Peripheral Proteins
23
Q
- Involved in cell recognition (part of immune system)
- Act as receptors in signaling (as with hormones)
A
Glycoproteins
24
Q
- Reduces fluidity in plasma membrane, thus increasing stability
A
Cholesterol
25
* Specific to molecules
* Changes shape slightly to transport
* Down concentration gradient - facilitated diffusion
* Against concentration gradient - active transport
Carrier Protein
26
* Detect hormones to signal changes in cell function
* Involved in other cell and substance recognition (ex. in immune system)
Receptor Proteins
27
* Catalytic proteins
* End in -ase
* ex. ATP Synthetase, Maltase
Enzymes
28
* Seen in **photosynthesis** and respiration in oxidation/reduction reactions
Electron Carriers
29
* No energy required
* High concentration -\> low concentration
* Caused by kinetic energy of particles
* Direction of movement random
Diffusion
30
* The location that supplies and maintains the concentration of particles is called the **source**
* The location where the substance is continually removed (or changed) is called the **sink**
* Maintaining the **concentration gradient** between the two areas is a feature of biological systems
**Source = blood oxygen in lungs Sink = respiring cell**
Diffusion through a membrane (ex. lungs)
31
* Diffusion of water through a membrane
Osmosis
32
Oxygen, Carbon Dioxide, Water, Lipids (hydrophobic)
What molecules pass through the membrane with little resistance?
33
* Chanel proteins - create a tunnel for large molecules
* Carrier proteins
Facilitated (passive) Transport Across Membranes
34
* Against concentration gradient (low to high cocentration)
* Requires energy (ATP, produced in cell respiration)
* Carrier proteins
* Sodium-potassium pump/Hydrogen-proton pump
* Cells are negatively charged on the inside relative to the outside (creates voltage)
Active Transport Across the Membrane
35
1. The protein is moved through the rER and modified
2. A sperical vesicle is formed from the end of the rER with the protein inside
3. Vesicle and golgi membranes fuse. The protein is released into the lumen of the golgi apparatus
4. The golgi modifies the protein further
5. A new vesicle is formed from golgi membrane which then breaks away
6. The vesicle migrates to the plasma membrane fuses secretes content. A process called exocytosis.
Exocytosis
36
a vesicle is formed by the enfolding of the plasma membrane
3 types: phagocytosis (cellular eating) pinocytosis (cellular drinking) and receptor-mediated endocytosis
Endocytosis
37
* Phospohlipid molecules changing places in horizontal plane caused fluid property of membrane
* Cholesterol reduces fluidity
* Unsaturated hydrocarbon tails - kinks, double bonds, fluid
* Saturated hydrocarbon tails - no kinks, no double bonds, viscous
Membrane Fluidity
38
Facilitated (passive) diffiusion
Aquaporins (facilitated diffusion of water)
ion channels (gated channels, open/close in response to stimulus)
Channel Proteins
