BIOL 1001 Chapter : Chapter 5 Cell Membranes Part 2 Of 2

13 views2 pages

azuremammoth471

15 Mar 2019

School

Department

Course

Professor

For unlimited access to Textbook Notes, a Class+ subscription is required.

Document Summary

Chapter 5 cell membranes part 2 of 2. Cells need to move molecules against a concentration gradien (from low concentration to high concentration) This requires energy because its fighting diffusion. (like pumping water uphill) Active transport of solutes against a concentration gradient. Active transport is an energy-requiring process during which a transport protein pumps a molecule across a membrane against its concentration gradient. Used to maintain ion gradients (e. g. , ca2+ ions) Energy is also required for endocytosis and exocytosis. -endocytosis is the cellular uptake of large molecules (a. k. a. macromolecules) and particulate substances (food) by the localized pinching off of a region of the plasma membrane to form a vesicle. Three types: phagocytosis, pinocytosis and, receptor-mediated endocytosis. Endocytosis - phagocytosis (large particles) phagocytosis (cell eating) is the endocytosis of solid particles fig 5. 14. Pinocytosis (cell drinking) is the endocytosis of fluid droplets fig.

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

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

QUESTION 1

Ion diffusion across plasma membrane needs

		a concentration gradient across the membrane
		specific transporters
		ATP
		provide extra energy for the transport

2 points

QUESTION 2

There are four types of large biological molecules

2 points

QUESTION 3

Active transporters transport substances across cell membrane against ____________

2 points

QUESTION 4

Which of the following is a nonpolar amino acid?

	1.	Valine
	2.	Serine
	3.	Aspartic acid
	4.	Glutamic acid

2 points

QUESTION 5

Membrane potential of a cell is created by:

	1.	sodium ion concentration difference between inside and outside of the cell
	2.	a difference in protein concentration across the cell membrane
	3.	an electrical potential difference between the intracellular fluid and the surrounding extracellular fluid
	4.	a difference between the potassium concentration inside and outside of the cell

2 points

QUESTION 6

A mutation resulted in a change from a valine to a glutamic acid in a peptide sequence. This mutation will NOT change the protein folding

True

False

2 points

QUESTION 7

Ions can be transported across plasma membrane by

	1.	diffusion
	2.	No need of transporters
	3.	osmosis
	4.	active transport

2 points

QUESTION 8

Phospholipid is composed of

	1.	A glycerol backbone
	2.	One protein group
	3.	One carbohydrate group
	4.	Two fatty acid chains and one phosphate group

2 points

QUESTION 9

Prokaryotic cells and eukaryotic cells are similar in

	1.	Plasma membrane
	2.	nucleus
	3.	mechanism for protein translation
	4.	endoplasmic reticulum

2 points

QUESTION 10

Disulfide bonds are formed between two histidine residues

True

False

BIOL 1001 Chapter : Chapter 5 Cell Membranes Part 2 Of 2

Document Summary

Get access

Related Documents

BIOL 1001 Chapter : Ch 5 Pt 2

BIOL 1001 Chapter : Chapter 5 Cell Membranes Part 2 Of 2

BIOL 1001 : Biology 1001 Test 3

Related Questions