BIOL 112 Lecture Notes - Lecture 11: Active Transport, Electrochemical Gradient, Passive Transport

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28 Jan 2017

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BIOL 112 Full Course Notes

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Facilitated diffusion: uses the help of a protein. Passive transport just means that it does not require energy, but it includes the two forms of passive transport listed above. In passive transport, the molecules follow the concentration gradient ([high] to [low] concentration) Uses energy directly to move molecules against a concentration gradient. Example: the na+ k+ pump moves na+ out and k+ ions against their concentration gradient. The role of atp in this process is to provide the energy to open: secondary active transport the pump. Active transport to pump an ion (ex: h+), this generates and electrochemical gradient. A second channel uses the energy from the electrochemical gradient to actively move a second molecule. Have lots of different shapes, which are decided by the polypeptide chain/the folding. Also, the shape is determined by how the side chains (r groups) interact with each other. Proteins can be found in the lipid bilayer, working as transporters, receptors, enzymes or anchors.

Related Questions

3. In an aqueous environment, the phospholipids of a membrane____.

a) are arranged in a single layer

b) are arranged in a bilayer with the polar heads of each layerlocated at the surface

c) are arranged in a bilayer with the fatty acid tails locatedat the surface

d) are arranged in a bilayer but the phospholipids have nospecific orientation

e) dissolve

4. which of the following molecules demonstrate dual solubilitycharacteristics

a) sterols only

b) proteins only

c) phospholipids only

d) sterols and phospholipids

e) sterols, phospholipids, and proteins

5. The "mosaic" part of the fluid mosaic model refers to themembrane ____.

a) proteins

b) phospholipids

c) cholesterol

d) functions

e) layers

9. Transport of a molecule across a cell membrane by facilitateddiffusion ____.

a) does not exhibit specificity for a particular type ofmolecule

b) requires the input of energy

c) depends on a concentration gradient

d) goes against the concentration gradient

e) allows non-polar uncharged molecules to diffuse across amembrane

13. A transport system in which transport of an ion in onedirection provides the energy for active transport in the oppositedirection is known as ____.

a) primary active transport

b) active diffusion

c) secondary active transport

d) cotransport

e) osmosis

14. Cells undergo exocytosis ____.

a) to pump protons down a concentration gradient

b) when replicating

c) to secrete protein and wastes from the cell

d) to ingest nutrients

e) as a means of cellular protection

15. What is the molecular basis of familialhypercholestremia?

a) HDL enters cells using a specific receptor on the cellsurface

b) LDL enters cells using a specific receptor on the cellsurface

c) HDL exits cells using a specific receptor on the cellsurface

d) LDL exits cells using a specific receptor on the cellsurface

e) receptor-mediated exocytosis

16. Carrier molecules are utilized for ____.

a) active transport only

b) passive transport only

c) both active and passive transport

d) osmosis

e) transport of all types of molecules

17. All of the following are functions of integral membraneproteins EXCEPT ____.

a) transport of polar molecules

b) reception of chemical signals form other cells

c) cell division

d) recognition of other cells as being "like"

e) cell-cell binding

olivecod348

A hypertonic solution has a higher level of solutes so the water moves out of the cells to the surroundings

A hypotonic solution has a higher level of solutes so the water moves out of the cells to the surroundings

The salt and water solution in the potato is a hypotonic solution

Osmosis is the movement of large molecules across a membrane which require embedded proteins

The plain water in this experiment is the solvent and the salt is the solute.

Passive transport requires no energy and the molecules move with the concentration gradient or from high concentration to low concentration

Active transport required no energy and the molecules move with the concentration gradient or from high concentration to low concentration.

The water on the inside of the potato with the salt molecules is an isotonic solution the same as the solution on the outside of the potato.

Water will not move by simple diffusion (osmosis) into or out of cells it requires energy or protein transporters

The solution of salt water in the potato has a lower concentration of water molecules so the water on the outside should move into the cells

Question 1

Plasma membranes are selectively permeable. This means that

	A.	glucose cannot enter the cell.
	B.	the plasma membrane allows some substances to enter or leave a cell more easily than others.
	C.	plasma membranes must be very thick.

Question 2

Oxygen molecules O₂ crosse a plasma membrane by

	A.	passive transport
	B.	osmosis
	C.	active transport

Question 3

Facilitated diffusion across a biological membrane requires ________ and moves a substance ________ its concentration gradient.

		A. energy and channel proteins; against (up)
		B. transport proteins that make channels ; down
		C. energy ; down

Question 4

When two aqueous solutions that differ in solute concentration are placed on either side of a semipermeable membrane and osmosis is allowed to take place, the water will

		A. move to the side with lower water concentration
	B.	move to the side with higher water concentration
	C.	move to the side with lower solute concentration

Question 5

Kinetic energy differs from chemical energy in that

	A.	chemical energy is a particular form of kinetic energy.
	B.	kinetic energy is the energy of a moving object, whereas chemical energy is the potential energy of molecules.
	C.	kinetic energy is stored energy that has the potential to do work, and chemical energy is the energy of movement.

Question 6

When a cell uses chemical energy to perform work, it uses the energy released from a(n) ________ reaction to drive a(n) ________ reaction.

	A.	exergonic; endergonic
	B.	endergonic; exergonic
	C.	spontaneous; exergonic

Question 7

When an enzyme catalyzes a reaction

		A. it raises the activation energy of the reaction.
		B. it lowers the activation energy of the reaction.
		C. it is used once and discarded.

Question 8

Which of the following statements regarding enzyme function is false?

		A. An enzyme's function depends on its three-dimensional shape.
		B. Enzymes are very specific for their substrates.
		C. Enzymes are used up when they catalyze a chemical reaction so must be synthesized for each new chemical reaction

BIOL 112 Lecture Notes - Lecture 11: Active Transport, Electrochemical Gradient, Passive Transport

BIOL 112 Full Course Notes

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