The Cell and Its Environment

Question 1

What is homeostasis?

Answer 1

Biological balance

Balance that every organism, organ, and cell must maintain in face of constant changing conditions

Question 2

What is an example of homeostasis at the organism level?

Answer 2

When humans are hot, they sweat, drink cold liquids, turn on AC
Pike (fish) seek cold water at the bottom of the pond

Question 3

What is an example of homeostasis at the organ level?

Answer 3

Heart with exercise beats faster. Weakened heart will beat faster causing growth.
If one kidney fails, the other will take over and increase in size.
If both fail, dialysis will filter waste from the blood.

Question 4

What are the three types of membranes?

Answer 4

Semi-permeable membrane: regulates what enters and leaves the cell
Permeable membrane: all molecules can enter and leave
Nonpermeable membrane: no molecules

Question 5

What determines if a molecule enters a cell or not?

Answer 5

Size of molecule
Size of pores
Concentration of molecules inside and outside cell

Question 6

What are the two types of transport in a cell?

Answer 6

Active transport: molecules move in and out of a cell due to energy within the cell
Passive transport: molecules move in and out of a cell and the cell has no control

Question 7

What is diffusion?

Answer 7

Movement of molecules from an area of higher concentration to an area of lower concentration

Question 8

What is equilibrium?

Answer 8

Concentration of molecules is equal inside and outside the cell

Question 9

What two factors affect diffusion?

Answer 9

Temperature- with increased temperature, rate of diffusion increases
Pressure- molecules move from an area of greater pressure to an area of lesser pressure

Question 10

What is osmosis?

Answer 10

Water molecules move from an area of greater concentration to an area of lesser concentration

Question 11

What is turgor?

Answer 11

Internal water pressure

Question 12

What results from too much turgor in an animal cell?

Answer 12

Cytolysis- the bursting of a cell

Question 13

How do some single celled organisms regulate water intake?

Answer 13

Using a contractile vacuole “sump pump”

Question 14

How do fish regulate water intake?

Answer 14

Gills rid of water

Urinate

Question 15

How do humans regulate water intake?

Answer 15

Urinate
Sweat
Cry
Breathe

Question 16

What is a hypotonic solution?

Answer 16

Greater concentration of solutes inside the cell so water enters the cell

Question 17

What is a hypertonic solution?

Answer 17

Concentration of solutes is greater outside the cell, water leaves the cell

Question 18

What is an isotonic solution?

Answer 18

When the concentration of solutes and water is equal both inside and outside the cell (strive toward isotonic solution)

Question 19

What happens when a paramecium is placed in distilled water as opposed to pond water?

Answer 19

Distilled water creates a hypotonic solution, so water enters the cell through osmosis causing cytolysis. Pond water creates a hypertonic solution so water exits the cell through osmosis to dissolve other particles.

Question 20

What is the difference between equilibrium and an isotonic solution?

Answer 20

In equilibrium, one molecule is equal. In an isotonic solution, all molecules are equal.

Question 21

What is plasmolysis?

Answer 21

Loss of turgor

Causes plants to wilt and die

Question 22

What are two possible causes of plasmolysis?

Answer 22

Lack of water

Over-fertilization

Question 23

What is an example of active transport?

Answer 23

Iodine molecules entering algae cells

Question 24

What would probably happen to an animal cell if we inject it with chloroform?

Answer 24

If injected with a little, it would lose cytoplasm but will repair itself.
If injected with a lot, cell will die.