The Internal Environment of Orgainsms (Study Guide)

Question 1

Your muscle cells have to expend more energy to do their job than your skin cells. Where does this energy come from? Which organelle will your muscle cells have more of as a result?

Answer 1

Energy comes from cellular respiration- the food you eat. Mitochondria get the energy out, so your muscle cells have more mitochondria.

Question 2

In a plant, where does photosynthesis happen? Which organelle?

Answer 2

Photosynthesis happens in chloroplasts

Question 3

What are all living things made of?

Answer 3

cells

Question 4

Describe active transport. How is it different from osmosis or diffusion?

Answer 4

It requires energy from the cell- moving material AGAINST the concentration gradient. Osmosis and diffusion are passive- require no cell energy

Question 5

Where does the energy for osmosis and diffusion come from?

Answer 5

Potential energy

Question 6

What is homeostasis? Why is this important?

Answer 6

Homeostasis - maintaining a constant internal environment, regardless of what happens in the external environment. You must maintain homeostasis to live

Question 7

How does sweating help maintain homeostasis?

Answer 7

Removes the heat, urea, and salt

Question 8

What is passive transport? How is it related to concentration gradient?

Answer 8

Requires no energy from the cell, materials move DOWN the concentration gradient.

Question 9

List types of passive transport. How are they all the same? How are they all different?

Answer 9

Osmosis, diffusion, facilitated diffusion. Same= none require cellular energy. Different = osmosis is h2o only, diffusion is any molecules, facilitated diffusion is large molecules

Question 10

Define diffusion. What direction do the molecules always move?

Answer 10

Movement of molecules from area of high concentration to low concentration. Molecules always move DOWN the concentration gradient.

Question 11

What is equilibrium? How does a substance reach equilibrium? Does motion stop at this point?

Answer 11

Equilibrium= concentration of molecules the same throughout. A substance reaches equilibrium when the concentration is the same = no more concentration gradient. Motion does not stop, but then molecules move in equal #’s in both directions.

Question 12

What does permeability describe? How do permeability and selectively permeability differ?

Answer 12

Ability of molecules to move across a membrane. Permeable= any molecule can move across. Selectively permeable = only some molecules can move across

Question 13

What are some limits to molecules passing through a membrane?

Answer 13

Size of molecules, temperature of molecules, charge of molecule

Question 14

What is osmosis? What direction does it move?

Answer 14

Osmosis= diffusion of WATER only. Moves down the concentration gradient

Question 15

Why can water move through a membrane and not other molecules?

Answer 15

Water is little and fast

Question 16

How does osmosis differ from diffusion? How are they the same?

Answer 16

Osmosis is diffusion of water only, both are movement from area of high concentration to low concentration- down the concentration gradient

Question 17

Describe each term and tell which direction we will see water moving
Hypertonic-
Hypotonic-
Isotonic-

Answer 17

Hypertonic- more solute in container than in cell- water will move OUT of the cell
Hypotonic- less solute in container than in cell- water will move INTO cell
Isotonic- same amount of solute in container and cell- water will NOT move

Question 18

In the dialysis tubing lab what was the tubing simulating? What went through? What didn’t?

Answer 18

Cell membrane. H20, glucose, and iodine went through. Starch didn’t because it’s too big

Question 19

What is active transport? How does it differ from passive transport? Why is active transport needed?

Answer 19

Active transport= movement f a molecule AGAINST the concentration gradient. Requires energy from the cell. It is needed because sometimes cells have to move molecules against the gradient (to get rid of wastes, etc.)

Question 20

In what form is the cellular energy needed for active transport? Where does it come from?

Answer 20

ATP is needed for active transport. It comes from cellular respiration (occurs in mitochondria)

Question 21

List the methods of active transport

Answer 21

Protein pumps, endocytosis, exocytosis

Question 22

How are vesicles used in active transport? How are they recycled throughout the cell?

Answer 22

For endo & exocytosis to move materials into and out of a cell. They are made of cell membrane, so they can merge with membrane and become part of it

Question 23

Explain endo and exocytosis. Give examples of what each would be used for?

Answer 23

Endo is bringing materials in- glucose can be moved into the cell. Exo is moving molecules out- proteins can be moved out

Question 24

From the egg lab- is the membrane of an egg selectively permeable? How do you know?

Answer 24

Yes, the “egg goo” didn’t come out of the membrane and into the beker in the hypertonic solution

Question 25

Where do the circulatory system and the excretory system meet? What happens there?

Answer 25

They meet in the kidneys. Blood enters, is filtered, and clean blood is put back in circulation