Bio Lect3 Flashcards
1
Q
What does membrane transport deal with?
A
The transport of molecules, particularly ions, across biological membranes
Membrane transport is crucial for maintaining cellular homeostasis.
2
Q
What is meant by ‘trans’-membrane transport?
A
The movement of substances across biological membranes
This includes ion transport and nutrient transport.
3
Q
Membrane transport involves the transport of what specific types of molecules?
A
Ions and nutrients
These molecules are essential for various cellular functions.
4
Q
True or False: Membrane transport refers to the transport of membranes.
A
False
It specifically refers to the transport of molecules across membranes.
5
Q
Why is membrane transport necessary for life?
A
Membrane transport is necessary for life to protect metabolic reactions within the cell against the environment
This protection is crucial for maintaining homeostasis and cellular function.
6
Q
What role does membrane transport play in communication?
A
Membrane transport is necessary for life to communicate and exchange materials between the cell and the environment
This exchange is vital for nutrient uptake and waste removal.
7
Q
What function do transport proteins serve in the cell membrane?
A
Transport proteins allow for the ‘controlled’ interaction of the cell with the environment
These proteins help regulate what enters and exits the cell, ensuring proper cellular function.
8
Q
What is the permeability of membranes for small hydrophobic molecules and gases?
A
High permeability
Examples include O2
9
Q
What is the permeability of membranes for water?
A
Limited permeability
10
Q
What is the permeability of membranes for ions such as potassium and large solutes like glucose?
A
Very low permeability
11
Q
What do transport proteins create in the membrane?
A
A hydrophilic passage
12
Q
Name two functions of transport proteins in membranes.
A
- Create a filter
- Provide possibility for energy coupling
13
Q
What is the protective function of the membrane primarily attributed to?
A
The lipid bilayer
14
Q
What type of barrier does the lipid bilayer present?
A
A diffusion barrier for most molecules
15
Q
What molecules does the lipid bilayer allow to diffuse freely?
A
Small hydrophobic molecules and gases
16
Q
Fill in the blank: The lipid bilayer is a barrier for all other molecules, particularly __________.
A
ions such as potassium and sodium
17
Q
Which large solutes are mentioned as having very low permeability in the membrane?
A
Sugars and peptides
18
Q
What is one potential regulation function of transport proteins?
A
Provide possibility for regulation
19
Q
What is facilitated diffusion?
A
A process where transport proteins create a hydrophilic pore for molecules to diffuse through.
20
Q
What role do transport proteins play in facilitated diffusion?
A
They create a hydrophilic pore that allows molecules to diffuse through.
21
Q
Fill in the blank: A _______ is an example of a water channel used in facilitated diffusion.
A
aquaporin
22
Q
True or False: Molecules can directly diffuse through the lipid bilayer during facilitated diffusion.
A
False
23
Q
What are the two types of forces that drive the movement of molecules across membranes?
A
Chemical gradient and electrical gradient
24
Q
What does the chemical gradient refer to?
A
Concentration gradient
25
What does the electrical gradient refer to?
Charge gradient
26
Which gradient is relevant only for charged molecules?
Electrical gradient
27
Provide an example of a cation.
Proton H+
## Footnote
Other examples include Potassium K+, Ammonium NH4+, Histidine, and Spermidine.
28
Provide an example of an anion.
Chloride Cl-
## Footnote
Other examples include Nitrate NO3-, Glutamate, Malate, and Pyruvate.
29
What type of molecules do cations refer to?
Positively charged ions
30
What type of molecules do anions refer to?
Negatively charged ions
31
What is the electrochemical gradient?
The net driving force for the movement of a molecule resulting from the combination of the chemical and electrical gradient.
## Footnote
This gradient influences how molecules move across membranes.
32
What is the case for an uncharged molecule in terms of the electrochemical gradient?
Movement is driven solely by the chemical gradient.
## Footnote
Uncharged molecules do not respond to electrical gradients.
33
What happens in the case of a cation in an electrochemical gradient?
Cations move toward areas of lower concentration and are attracted to negatively charged regions.
## Footnote
Cations carry a positive charge, influencing their movement.
34
What is the behavior of an anion in an electrochemical gradient?
Anions move toward areas of higher concentration and are attracted to positively charged regions.
## Footnote
Anions carry a negative charge, affecting their directional movement.
35
True or False: The direction of the net driving force for an anion depends on the relative sizes of chemical and electrical gradients.
True
## Footnote
The balance between these gradients determines the overall movement.
36
What determines the energy requirement of transport?
The electrochemical gradient
## Footnote
The electrochemical gradient is a combination of the concentration gradient and the electrical gradient across a membrane, influencing the movement of ions and molecules.
37
What is active transport?
Active transport moves substances against the electrochemical gradient and requires the input of energy.
38
What is passive transport?
Passive transport moves substances down the electrochemical gradient and requires no input of energy.
39
True or False: Active transport requires energy.
True
40
True or False: Passive transport requires energy.
False
41
What is the relationship between active transport and passive transport?
Active transport is a prerequisite for passive transport.
42
Fill in the blank: Active transport moves substances against the _______.
electrochemical gradient
43
Fill in the blank: Passive transport moves substances down the _______.
electrochemical gradient
44
What is required to establish the electrochemical gradient?
Energy investment
45
What is the difference between active and passive transport?
Active transport requires energy, while passive transport does not.
46
Name the transport proteins involved in active transport.
* Pumps
* Co-transport systems
47
What are the transport proteins involved in passive transport?
* Channels
* Carriers
48
Fill in the blank: _______ transport requires energy to move substances across a membrane.
[Active]
49
True or False: Passive transport can occur against the concentration gradient.
False
50
What type of transport uses channels and carriers?
[Passive transport]
51
Fill in the blank: _______ systems are a type of transport protein used in active transport.
[Co-transport]
52
What is the function of the sodium/potassium pump?
To transport sodium and potassium ions across the cell membrane
## Footnote
It maintains the electrochemical gradient essential for various cellular functions.
53
What type of energy do pumps like the sodium/potassium pump utilize?
Energy coupling
## Footnote
This process is coupled to the hydrolysis of ATP.
54
What are ATPases?
Transport proteins that couple transport to the hydrolysis of ATP
## Footnote
They play a critical role in active transport mechanisms.
55
Which pump is driven by light energy?
Bacteriorhodopsin
## Footnote
It is an example of a light-driven pump.
56
What occurs during the conformational change of the sodium/potassium pump?
The transporter binds 3 Na+ from the inside of the cell
## Footnote
This change is crucial for the pump's function.
57
What does phosphorylation favor in the sodium/potassium pump?
P-Enzi*
## Footnote
Phosphorylation is an essential step in the pump's mechanism.
58
What does the sodium/potassium pump release to the outside of the cell?
3 Na+
## Footnote
This release is part of the ion exchange process.
59
How many K+ ions does the sodium/potassium pump bind from the outside of the cell?
2 K+
## Footnote
This is part of the pump's function to maintain ion balance.
60
What does dephosphorylation favor in the sodium/potassium pump?
Enzi
## Footnote
Dephosphorylation is the reverse step that resets the pump.
61
List examples of pumps.
* Sodium/potassium pump
* Proton pump
* Calcium pump
## Footnote
These pumps are crucial for various cellular processes.
62
Fill in the blank: The sodium/potassium pump transports _______ ions out of the cell and _______ ions into the cell.
3 Na+, 2 K+
## Footnote
This specific ion exchange is vital for maintaining membrane potential.
63
True or False: The sodium/potassium pump only transports sodium ions.
False
## Footnote
It also transports potassium ions into the cell.
64
What is the first step in the pump mechanism?
Three Na+ ions bind to cytoplasmic high-affinity binding sites.
65
What occurs during the second step of the pump mechanism?
ATP is hydrolyzed, transferring a phosphate group to the pump.
66
What happens in step three of the pump mechanism?
The pump conformation changes, moving Na+ ions to the extracellular side of the membrane.
67
What is the fourth step in the pump mechanism?
Na+ ions dissociate, and two K+ ions bind to high-affinity extracellular sites.
68
What occurs in the fifth step of the pump mechanism?
The bond linking phosphate to the pump protein is hydrolyzed, releasing inorganic phosphate.
69
What happens during the sixth step of the pump mechanism?
The pump conformation changes, moving K+ ions to low-affinity cytoplasmic sites.
70
What is the final step of the pump mechanism?
K+ ions dissociate, and the pump is ready for another cycle.
71
What do pumps establish in cells?
Electrochemical gradients
## Footnote
Electrochemical gradients are created by the movement of ions across membranes, which is crucial for various cellular processes.
72
What molecule is often associated with energy transfer in cells?
ATP
## Footnote
ATP (adenosine triphosphate) is the primary energy carrier in living organisms.
73
What type of pump is responsible for moving H+ ions?
Proton pump
## Footnote
Proton pumps transport protons across membranes, contributing to the establishment of electrochemical gradients.
74
Fill in the blank: The cytoplasm contains _______ ions.
H+
## Footnote
The presence of H+ ions in the cytoplasm is essential for maintaining pH and driving various biochemical reactions.
75
What can be driven by the electrochemical gradients established by pumps?
Active transport of other molecules
## Footnote
Active transport relies on energy to move substances against their concentration gradient, often utilizing the gradients created by pumps.
76
True or False: Electrochemical gradients are only used for the transport of H+ ions.
False
## Footnote
Electrochemical gradients can drive the transport of various ions and molecules, not just H+.
77
What is the role of extracellular fluid in relation to H+ ions?
Contains H+ ions
## Footnote
The extracellular fluid's concentration of H+ ions contributes to the electrochemical gradients across the cell membrane.
78
What do co-transporters couple together?
The downward movement of one ion (driver) to the uphill movement of another solute (substrate)
## Footnote
Co-transport systems are essential for various cellular processes, including nutrient absorption and ion regulation.
79
What is the definition of symport?
A co-transport system where the driver ion and substrate move in the same direction ('piggyback' principle)
## Footnote
Symport mechanisms are important in various biological systems, facilitating the transport of molecules across membranes.
80
What are co-transport systems?
Co-transporters couple the downward movement of one ion (driver) to the uphill movement of another solute (substrate).
81
What is antiport in co-transport systems?
Driver ion and substrate move in the opposite direction ('revolving door' principle).
82
Fill in the blank: Co-transporters couple the downward movement of one ion (_______) to the uphill movement of another solute (substrate).
[driver]
83
True or False: In antiport systems, the driver ion and substrate move in the same direction.
False
84
What is transport coupling?
The functional linkage of primary pumps with co-transport systems
## Footnote
Transport coupling is essential for various cellular processes.
85
Is transport coupling inherent to all life forms?
Yes
## Footnote
This indicates its fundamental role in biological functions.
86
In which parts of the cell does transport coupling occur?
Different cells and organelles
## Footnote
This includes a variety of cellular structures.
87
What is passive transport?
Passive transport moves substances down the electrochemical gradient
88
Does passive transport require energy?
No, it requires no input of energy
89
What does passive transport rely on?
Previously established electrochemical gradients, formed by the active transport.
90
What are the types of transport proteins involved in passive transport?
Transport proteins for passive transport include:
* Channels
* Carriers
91
What is passive transport?
A process that allows substances to cross membranes without energy input
## Footnote
Passive transport relies on concentration, electrical gradients.
92
What role does a channel play in passive transport?
Provides an aqueous pore for the passage of ions
## Footnote
Channels facilitate the movement of ions based on their electrochemical gradients.
93
How does a carrier function in passive transport?
Undergoes a conformational change that exposes ion binding sites to different sides of the membrane
## Footnote
This mechanism allows for the selective transport of specific ions.
94
What do both channels and carriers facilitate in passive transport?
The movement of solutes down their electrochemical gradients
## Footnote
This movement is driven by the natural tendency of solutes to move from areas of higher concentration to lower concentration.
95
What is the primary function of ion channels?
They exert a tight control of passage.
96
Are ion channels selective?
Yes, they are selective.
97
How much more permeable are some K+ channels to K+ compared to Na+?
100-fold higher permeability.
98
What does it mean that ion channels are 'gated'?
They can open and close upon specific stimuli.
99
What types of stimuli can cause ion channels to open or close?
Voltage and chemical ligands.
100
Fill in the blank: Ion channels are not just _______.
[pores]
101
True or False: Ion channels allow any ion to pass through without selectivity.
False.
102
What is an example of a physiological process that involves ion channels?
Action potential.
103
What method is used to measure how single channel proteins gate?
Patch clamp
## Footnote
The patch clamp technique allows for the study of individual ion channels in detail.
104
What device is essential for the patch clamp method?
Current amplifier
Suction pipettes
## Footnote
The current amplifier is used to detect the tiny ionic currents flowing through the ion channels.
105
What tool is used to create a seal with the cell membrane in patch clamp?
Suction pipette
## Footnote
The suction pipette is crucial for establishing a high-resistance seal with the membrane to isolate the ion channel.
