BI110 Lecture Notes - Lecture 9: Membrane Transport Protein, Atp Hydrolysis, Lipid Bilayer

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goldant554

4 May 2017

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Hydrophobic nature of membranes restricts free movement of many molecules and substances essential for life. Passive transport: the movement of a substance across a membrane without need to expend chemical energy such as atp (cid:894)aka atp isn"t produced(cid:895) Diffusion: net movement of a substance from region of higher to lower concentration. Primary mechanism of solute movement within a cell and between cellular compartments separated by a membrane. Rate of diffusion depends on the concentration difference on two sides of membrane, or concentration gradient. The gradient itself is a form of potential energy atp is(cid:374)(cid:859)t used (cid:271)ut you still (cid:374)eed e(cid:374)ergy to get so(cid:373)ethi(cid:374)g to move. The bigger the gradient the more potential energy it has, and the faster the rate of transportation it will have. Diffusion rate is affected by temperature (more higher temp, more energy, more movement, more diffusion) Any temperature, the smaller molecule diffuses faster than the larger molecule.

Related Questions

1 Which of the following statements is false?

(a) CO₂ and O₂ can diffuse freely across the cell membranes.

(b) The differences in permeability between artificial lipid bilayers and cell membranes arise from variations in phospholipid content.

(d) Cells expend energy in the form of ATP hydrolysis to maintain ion concentrations that differ from those found outside the cell.

2 Cells use membranes to help maintain set ranges of ion concentrations inside and outside the cell. Which of the following ions is the most abundant inside a typical mammalian cell?

(a) Na⁺

(b) K⁺

(d) Cl^â

3 Pumps are transporters that are able to harness energy provided by other components in the cells and drive the movement of solutes across membranes, against their concentration gradient. This type of transport is called _____________.

(a) active transport.

(b) free diffusion.

(d) passive transport.

harlequinbuffalo618

1,Match the descriptions to the type of transport.

- A. B. C.	Water enters a cell because it is hypertonic compared to the extracellular environment, increasing its turgor pressure
- A. B. C.	Water enters guard cells because the guard cells are hypertonic compared to the surrounding cells
- A. B. C.	Potassium ions are pumped into guard cells
- A. B. C.	The motor cells of a Venus fly trap are hypotonic compared to surrounding cells, causing water to leave the motor cells
- A. B. C.	Sugar is loaded into the phloem

A.	Both active and passive transport
B.	Passive Transport
C.	Active transport

2,Describe what is wrong with the following statement and explain why:

All prokaryotic and eukaryotic cells contain plasma membrane, nucleus, ribosomes, organelles, cytoplasm, and cell walls.

What is short-distance transport?

	a,	The movement of solutes from a region of low concentration to a region of high concentration
		b,The movement of water, nutrients, and other substances between cells
c,		The movement of substances from a region of high concentration to a region of low concentration
d,		The movement of water across a semipermeable membrane from a region of low solute concentration to a region of high solute concentration.

What terms describe the movement of water across a semipermeable membrane from a region of high water concentration towards a region of low water concentration (and high solute concentration.)

What is found in the proptoplasm?

Cell wall, cytoplasm, plasma membrane, nucleus, and other cell organelles

Plasmodesmata, cell wall, and plasma membrane

Cell wall, cytoplasm, and plasma membrane

Cytoplasm, nucleus, and other cell organelles

The channels that allow nutrients and protoplasm to pass between plant cells are called _________________.

What happens when a plant cell is placed in a hypotonic solution?

Water will enter the plant cell and the plasma membrane will swell and cell lysis will occur

Water will leave the plant cell and the plasma membrane will pull away from the cell and plasmolysis will occur

Water will enter the plant cell and the plasma membrane will swell and push against the cell wall

Water will leave the plant cell and the plant cell will lose turgor pressure, causing the plant to wilt

________________ transport uses cellular energy.

What molecules make plasma cell membranes hydrophilic on the outside and hydrophobic on the inside?

What type of cells do plants have?

		Bacterial
		Archaeic
		Eukaryotic
		Prokaryotic

1. Which of the following pairings are/is correct?

Cholesterol: has a hydrophilic and hydrophobic end
Cholesterol: does not have a hydrophilic end since it is a lipid
Cholesterol: is often times wedged in between the phospholipids
1st and 2nd choices only
1st and 3rd choices only
2nd and 3rd choices only
All of the above
None of the above

2. Which of the following pairing/s is/are correct?

Cholesterol: helps maintain the integrity of the cell membrane
Cholesterol: the rigid four carbon rings prevent lipid tails from packing too closely
Cholesterol: the rigid four carbon rings also prevent the membrane from being too fluid
1st and 2nd choices only
1st and 3rd choices only
2nd and 3rd choices only
All of the above
None of the above

3. Which of the following pairing/s is/are correct?

Membrane proteins: help maintain concentration gradients
Concentration gradient: the difference of amounts of solutes on two sides of a solution
Solutes: are the substances dissolved in a solution
1st and 2nd choices only
1st and 3rd choices only
2nd and 3rd choices only
All of the above
None of the above

4. Which of the following pairing/s is/are correct?

Molecules: move around randomly on their own
Molecules: when concentrated create an unstable environment due to increased collisions of molecules
Diffusion: is the movement of molecules from a region of low concentration to a region of high concentration
1st and 2nd choices only
1st and 3rd choices only
2nd and 3rd choices only
All of the above
None of the above

5. Which of the following pairing/s is/are correct?

Passive movement: movement of molecules that is energetically favorable b/c free energy is released in the process
Passive movement: requires energy from outside of the system
Passive movement: occurs as molecules move up their concentration gradients
1st and 2nd choices only
1st and 3rd choices only
2nd and 3rd choices only
All of the above
None of the above

6. Which of the following pairings/s is/are correct?

Active movement: is a passive process
Active movement: is an energetically unfavorable process
Active movement: releases free energy
1st and 2nd choices only
1st and 3rd choices only
2nd and 3rd choices only
All of the above
None of the above

7. Which of the following pairing/s is/are correct?

Transport channels: allow movement of all ions through
Transport carriers: allow movement of all ions through
Channels : passive movement
Carriers: active movement
1st and 2nd choices only
1st and 3rd choices only
1st, 2nd, and 3rd choices only
2nd and 3rd choices only
All of the above
None of the above

8. Which of the following paring/s is/are correct?

Active transporters: movement of molecules up their concentration gradients
Active transporters: require energy
Active transporters: ATP dependent pumps, antiporters, symporters
1st and 2nd choices only
1st and 3rd choices only
2nd and 3rd choices only
All of the above
None of the above

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BI110 Lecture Notes - Lecture 9: Membrane Transport Protein, Atp Hydrolysis, Lipid Bilayer

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