Chapter 5 Homeostasis and Cell Transport

Question 1

How does the cell membrane help organisms maintain homeostasis?

Answer 1

by being selectively permeable and controlling which substances enter and leave the cell

Question 2

What is passive transport?

Answer 2

substances crossing the cell membrane without the cell having to use any energy

Question 3

What type of molecules are involved with passive transport?

Answer 3

water, carbon dioxide, oxygen, glucose

Question 4

In what direction do the small molecules move during passive transport?

Answer 4

down the concentration gradient from an area where they are in high concentration to an area where they are in low concentration

Question 5

What is a concentration gradient?

Answer 5

the difference in the concentration of molecules across a distance

Question 6

What type of energy is passive transport driven by/

Answer 6

kinetic energy of the molecules themselves, so the cell does not use any energy

Question 7

How long does diffusion continue?

Answer 7

until equilibrium is reached and the concentration gradient no longer exists

Question 8

What happens to the molecules after equilibrium?

Answer 8

they continue to move equally in all directions

Question 9

What are the three types of passive transport?

Answer 9

diffusion, osmosis, and facilitated diffusion

Question 10

What is diffusion?

Answer 10

the type of passive transport which describes the movement of any molecule down its concentration gradient from an area of high concentration to low concentration

Question 11

What is osmosis?

Answer 11

the type of passive transport which describes the diffusion of water across a selectively permeable membrane

Question 12

What is selectively permeable?

Answer 12

when only certain molecules are allowed to pass through the membrane

Question 13

What is the solute of a solution?

Answer 13

the molecules being dissolved

Question 14

What is the solvent of the solution?

Answer 14

the fluid the molecules are being dissolved in

Question 15

What is the direction of osmosis determined by?

Answer 15

the solute concentrations on the two sides of a membrane. if the solute concentration is high the solvent concentration will be low and vice versa

Question 16

How is water the same as all molecules that move by diffusion?

Answer 16

they will move from an area of high concentration to an area of low concentration of water

Question 17

How do cells respond to the increase or decrease in water concentration in their cytosol?

Answer 17

by either shrinking or swelling

Question 18

What are the terms hypertonic, hypotonic, and isotonic used to describe?

Answer 18

the difference in concentration of solute from one side of a membrane to another

Question 19

How is something hypertonic?

Answer 19

when is has less solute than the other side of the membrane

Question 20

In what direction will water move if a cell is placed in a hypotonic solution?

Answer 20

the water will move into the cell

Question 21

What happens to the cells in hypotonic solutions?

Answer 21

they swell and may burst

Question 22

What is the bursting of cells called?

Answer 22

cytolysis

Question 23

How is something hypertonic?

Answer 23

when it has more solute than the other side of the membrane

Question 24

In what direction will water move if a cell is placed in a hypertonic solution?

Answer 24

water will move out of the cell

Question 25

What happens to a cell placed in a hypertonic solution?

Answer 25

the cell shrinks

Question 26

What is the shrinking of cells called?

Answer 26

plasmolysis

Question 27

How does something become isotonic?

Answer 27

at equilibrium the % of solute is the % on both sides of the membrane

Question 28

What type of environments do most single celled organisms live in?

Answer 28

hypotonic environments in which water is constantly entering

Question 29

How do single cell organisms compensate for the water constantly entering?

Answer 29

they have a specialized organelle called a contractle vacuole that removes excess water

Question 30

What do the cell walls of plant cells do?

Answer 30

they limit the amount of water that can enter plant cells

Question 31

What is turgor pressure?

Answer 31

the pressure that water molecules exert during the cell wall

Question 32

What will plants look like with low turgor pressure?

Answer 32

wilted

Question 33

What is facilitated diffusion?

Answer 33

a type of passive transport in which a molecule utilizes a carrier/transport protein to pass through the cell membrane

Question 34

What does a carrier protein do when a specific molecule binds to it?

Answer 34

the carrier proteins changes shape and transports the molecules down its concentration gradient (high to low) Ex. Glucose