science test #3 cell membrane

Question 1

define passive transport

Answer 1

a type of transport that requires no energy/atp (moves materials along concentration gradient) (LOW -> HIGH)

Question 2

define active transport

Answer 2

a type of transport that requires energy/atp (moves materials against concentration gradient) (HIGH -> LOW)

Question 3

What are the steps for passive transport?

Answer 3

diffusion, osmosis, facilitated diffusion

Question 4

what are the steps for active transport?

Answer 4

Endocytosis, exocytosis, Na-K pump

Question 5

What is permeability?

Answer 5

The degree to which a cell membrane allows substances to pass through.

Question 6

What is a semi-permeable membrane?

Answer 6

A membrane that only allows certain substances to pass through.

Question 7

What is an in-permeable membrane?

Answer 7

A membrane that allows no substances to pass through

Question 8

What is a fully permeable membrane?

Answer 8

A membrane that allows all substances to pass through

Question 9

What is the fluid mosaic model?

Answer 9

The model we use today to represent a cell membrane’s structure

Question 10

define endocytosis

Answer 10

A process in which molecules are entering the cell. (there are 3 types of endocytosis)

Question 11

define exocytosis

Answer 11

A process in which molecules are exiting the cell

Question 12

What are the 3 types of endocytosis?

Answer 12

Pinocytosis, Receptor-mediated cytosis, and phagocytosis.

Question 13

What is pinocytosis?

Answer 13

Pinocytosis is a form of active transport, the most common form of endocytosis. Materials dissolve in water to be brought into the cell.

Question 14

What is receptor-mediated endocytosis?

Answer 14

When integral proteins have receptors on them in order to take in proteins/ substances. A type of active transport.

Question 15

What is phagocytosis?

Answer 15

A type of active transport. It is used to engulf large particles in vesicles.

Question 16

Who discovered cells?

Answer 16

Robert E. Hooke.

Question 17

What is tonicity?

Answer 17

It describes how an extracellular solution can change the volume of a cell by affecting osmosis.

Question 18

What is osmolarity?

Answer 18

It describes the total solute dissolved in a solution (expressed as osmoles of solute per liter of water)

Question 19

What does low osmolarity indicate?

Answer 19

That there is a a greater number of water molecules relative to the number of solute particles.

Question 20

What does high osmolarity indicate?

Answer 20

That there is a fewer number of water molecules with respect to the number of solute particles.

Question 21

Define hypotonic

Answer 21

Extracellular fluid has lower osmolarity than the fluid inside the cell, and water enters the cell (cell will burst)

Question 22

Define hypertonic

Answer 22

Extracellular fluid has a higher osmolarity than the cells fluid. (cell will shrink due to lack of water)

Question 23

Define isotonic

Answer 23

Extracellular fluid has the same osmolarity as the cell (no net movement of water in and out) (cell retains shape) (cell is at equilibrium)

Question 24

Define equilibrium.

Answer 24

Also called homeostasis, it is a state of balance between the number of a certain type of particle on each side of the membrane.

Question 25

What are the two types of transport proteins?

Answer 25

Channel and carrier

Question 26

What is the difference between channel and carrier proteins

Answer 26

Channel proteins are always passive, whereas carrier proteins can be both.

Question 27

What is simple diffusion?

Answer 27

Movement down the concentration gradient. (PASSIVE TRANSPORT) Simple diffusion does not require the assistance of membrane proteins.

Question 28

the cell membrane is known as ___________________.

Answer 28

A phospholipid bi-layer.

Question 29

What is the main goal of a cell?

Answer 29

To reach equilibrium.

Question 30

What is the difference between osmosis and diffusion?

Answer 30

Osmosis is specific to water, while diffusion is not.

Question 31

Once a cell reaches equilibrium, what will happen to the molecules?

Answer 31

They will continue to move but maintain equilibrium.

Question 32

What is diffusion?

Answer 32

A passive process- no energy is used to make molecules move. The movement of molecules from areas of high concentration to low concentration.

Question 33

movement DOWN the concentration gradient is ___________.

Answer 33

passive

Question 34

movement AGAINST/ UP the concentration gradient is _______.

Answer 34

active

Question 35

What happens when the SA/V ratio is below 1:1?

Answer 35

It will not support the cell

Question 36

Will a smaller or larger radius sphere have a larger SA/V ratio?

Answer 36

SMALLER

Question 37

What is the formula for volume of a sphere

Answer 37

4/3πr

Question 38

What is the formula for surface area of a sphere

Answer 38

4πr²

Question 39

What is cytolisis?

Answer 39

The desctruction of a cell (swelling/burst) (HYPOTONIC)

Question 40

What is Plasmolysis?

Answer 40

The shrinking of a cell (shrinking/shirviling) (HYPERTONIC)

Question 41

What is facilitated diffusion?

Answer 41

A type of passive transport, that uses transport proteins to move molecules along the concentration gradient.

Question 42

The heads in a phospholipid bi-layer are made of ________

Answer 42

Phosphates

Question 43

The tails in a phospholipid bi-layer are made of ________.

Answer 43

Lipids