Cell Transport

Question 1

Homeostasis

Answer 1

Need of an organism to stay stable by regulation internal conditions

Question 2

Dynamic equilibrium

Answer 2

It is maintained and isn’t always the same, but things will stay within range

Question 3

Stimulus

Answer 3

Change in enviornment

Question 4

Response

Answer 4

A change in the organism, as a result of a stimulus

Question 5

Feedback

Answer 5

Mechanisms evolve to help maintain homeostasis in organisms as they respond to stimuli

Question 6

Positive feedback mechanisms

Answer 6

The output of a system intensifies the response. Example: human childbirth
Hormones->contractions->pressure->release of more hormones->more contractions->more pressure etc.
Fruit ripening
fruit ripens->released ethylene->signals surrounding fruit to ripen->neighboring fruit ripen->release more ethylene etc.

Question 7

Negative feedback mechanisms

Answer 7

The output of a system causes a counter response to return to a set point
Examples:
Human body temperature (thermo-regulation)
Water concentration (osmo-regulation)
Blood sugar regulation

Question 8

Passive cell transport

Answer 8

Passive transport requires NO extra energy by the cells because molecules move from high concentration (squished together) to low concentration (spread out) areas down the concentration gradient
Ex. Simple diffusion, facilitated diffusion , and osmosis

Question 9

Active cell transport

Answer 9

Active transport REQUIRES extra energy(ATP) to be spent to bring materials into the cell or expel materials out of the cell moving from low to high concentration against the concentration gradient.
Ex. Molecular pumps, exocytosis, endocytosis

Question 10

Active transport

Answer 10

When a cell uses energy to pump molecules across the membrane against the gradient through a protein channel/ This allows a cell to concentrate key molecules within the cell, or remove waste quickly from the cell.

Question 11

Using vessicles

Answer 11

Endocytosis: uses vesicles to mover large particles into the cell. Ex. When white blood cells engulf bacteria in order to fight infection

Exocytosis: Uses vesicles to move large particles out of the cell. Ex. When nerve cells secrete neurotransmitters to send signals throughout the body.

Question 12

Simple diffusion

Answer 12

The spreading out of molecules across a membrane until equilibrium is reached. Molecules move down a concentration gradient from high to an area of low. Ex, oxygen and carbon dioxide, and other small, non polar molecules

Question 13

Facilitated diffusion

Answer 13

A transport protein helps to facilitate the diffusion of molecules that normally couldn’t pass through the cell membrane. Transport proteins can act as a channel or a carrier. Molecules move down a concentration gradient from high [] to an area of low [].Ex. Large molecules like glucose (sugar) and polar molecules like calcium

Question 14

Osmosis

Answer 14

The simple diffusion of water across the cell membrane. Water molecules move down a concentration gradient, from high [water] to low [water]until equilibrium is reached. High water concentration means low solute concentration. Low water concentration means high solute concentration.

Question 15

Hypertonic solutions

Answer 15

Water [ ] is lower than the cell’s cytoplasm. Net movement of water out of cell -> cell