Biochem Chapter 8

Question 1

Membranes are

Answer 1

semipermeable

Question 2

What is passive transport

Answer 2

the movement of a substance across a membrane without the need to expend energy (ATP)

Question 3

What are the types of passive transport

Answer 3

Diffusion, Osmosis, Facilitated Diffusion

Question 4

What is diffusion

Answer 4

the net movement of molecules from an area of high concentration to an area of low concentration until it reaches dynamic equilibrium

Question 5

What types of molecules can diffuse across a membrane?

Answer 5

small and uncharged

Question 6

What types of molecules cannot diffuse across a membrane?

Answer 6

large and charged

Question 7

The rate of diffusion depends on …

Answer 7

Gradient - the greater the concentration difference the faster the movement

Temperature - the higher the temperature the quicker dynamic equilibrium will be reached

Question 8

What is osmosis

Answer 8

the net movement of water across a semipermeable membrane driven by a difference in solute concentrations on the two sides of the membrane

Question 9

How can water move through osmosis?

Answer 9

Freely, or through aquaporins

Question 10

Tonicity

Answer 10

the relative concentration of solutes dissolved in two solutions separated by a permeable membrane

Question 11

Hypertonic

Answer 11

Higher external concentration Ex. Salt Water

Question 12

Hypotonic

Answer 12

Lower external concentration. Ex pure water

Question 13

Isotonic

Answer 13

Equal concentration

Question 14

What happens when cells are put into a hypertonic solution?

Answer 14

Water will rush out of the cell and into the solution. Causes the cell to shrivel

Question 15

What happens when cells are put into a hypotonic

Answer 15

Water will rush into the cell potentially causing it to lyse.

Question 16

What happens to a cell put in an isotonic solution?

Answer 16

Nothing

Question 17

Facilitated Diffusion

Answer 17

the transport of ions and polar molecules through a membrane with the help of membrane proteins and without using energy

Question 18

Types of facilitated diffusion

Answer 18

Channel Proteins and Carrier Proteins

Question 19

What are channel proteins?

Answer 19

integral membrane proteins that form hydrophilic pathways in the membrane so substances like water and ions can cross. Some remain open at all times and others open and close in response to signals such as hormones, electric charge, and pressure

Question 20

What are carrier proteins?

Answer 20

They bind to a specific solute (ex. amino acids) and transport them across the lipid bilayer. When performing the transport step, the carrier protein changes shape, allowing the solute to move from one side of the membrane to the other. They are very selective about what they carry

Question 21

What is active transport?

Answer 21

the movement of substances across membranes against their concentration gradient using pumps. This is an energy-dependent process.

Question 22

What uses ATP directly to move molecules or ions against their concentration gradient

Answer 22

Primary Active Transport

Question 23

What is an example of primary active transport?

Answer 23

Sodium/Potassium Pump (Antiport)

Question 24

Ions/Molecules moving across in opposite directions

Answer 24

Antiport

Question 25

Primary Active transport creates

Answer 25

electrochemical gradients

Question 26

Electrochemical Gradients

Answer 26

the difference in charge across a membrane. It generates a force that drives ion diffusion until the charges are balanced on both sides of the membrane

Question 27

Chemical Gradient

Answer 27

the difference in solute concentration across a membrane. the ion will move across the membrane from high to low concentration through simple diffusion.

Question 28

Secondary Transport

Answer 28

uses the concentration gradient of an ion, established by a primary pump, as its energy source.

Question 29

Example of a secondary transport

Answer 29

Hydrogen-Sucrose pump. This is a symport.

Question 30

Bulk Transport

Answer 30

the movement of large molecules or large quantities of materials into or out of a cell at one time (does require energy)

Question 31

Forms of Bulk Transport

Answer 31

Exocytosis, Endocytosis

Question 32

What is exocytosis

Answer 32

the movement of large molecules out of the cell. Vesicles can release their contents into the extracellular environment

Question 33

What is endocytosis

Answer 33

the form of bulk transport used to bring large amounts of materials into the cell from the extracellular fluid. There are three types, receptor-mediated, phagocytosis, and pinocytosis

Question 34

What is receptor-mediated cytosis?

Answer 34

receptor proteins on parts of the outside of the cell membrane bind with the specific molecules, and the pit folds inward to form a vesicle. The contents of the vesicle can be digested.

Question 35

What is phagocytosis?

Answer 35

[eat] occurs only in specialized cells, such as amoeba or bacteria-eating white blood cells (macrophages). It begins when the solid particle comes in contact with the plasma membrane of the cell and the cell membrane sends out finger-like projections called pseudopods that eventually enclose a vesicle. lysosomes may fuse with a phagocytic vesicle to digest the contents

Question 36

Pinocytosis

Answer 36

[drink] occurs when a cells plasma membrane engulfs a small drop of extracellular fluid