Homeostasis & Cellular Transport (in Eukaryotic Cells)

Question 1

Any homeostatic process that changes the direction of stimuli.

Answer 1

Feedback Loop

Question 2

Maintains stimulus.
Sometimes even enhances it.

Answer 2

Positive Feedback Loop

Question 3

Stops or reduces the stimulus.

Answer 3

Negative Feedback Loop

Question 4

The tendency of living things to maintain a steady state (of internal conditions).

Answer 4

Homeostasis

Question 5

Reactions are happening, but put together, the reactions result in stable conditions.
Keeps the conditions close to their set points.
The rafte of the forward process matches the rate of the reverse process.

Answer 5

Dynamic Equillibrium

Question 6

The value around which a specific condition fluctuates.

Answer 6

Set Point

Question 7

Depend on the external environment to set their body temperature.
Cold-blooded —> fish, reptiles
Most do not have cold blood, but simply allow their body temperatures to fluctuate over a much wider range.

Answer 7

Ectotherms

Question 8

Regulation of temperature by organisms.

Answer 8

Thermoregulation

Question 9

Animals that can maintain their body temperature at set points through thermoregulation.
Warm-blooded animals —> most mammals and birds

Answer 9

Endotherms

Question 10

The loss of electromagnetic radiation as heat waves.
ex. Snakes basking in the sun to warm up or lions staying in the shade to cool down.

Answer 10

Radiation

Question 11

The loss of heat as a liquid becomes a gas.
ex. Sweat, panting, elephant spraying itself with water.

Answer 11

Evaporation

Question 12

Loss of heat due to air movement.
ex. Breeze, fan.

Answer 12

Convection

Question 13

Direct transfer of heat by molecules of an organism/object in direct contact.
ex. Sitting on a sun-warmed rock on a cool evening can transfer heat from the rock to the organism.

Answer 13

Conduction

Question 14

The primary way that cells maintain internal stability. —> Involves moving liquids, molecules, proteins, ions, and other solutes into/out of the cell.
Important to maintain correct levels inside/outside the cell.

Answer 14

Cellular Transport

Question 15

Water-attracting.

Answer 15

Hydrophilic

Question 16

Water-repelling.

Answer 16

Hydrophobic

Question 17

Often span the entire membrane.
Shuttle molecules/ions in/out of the cell.

Answer 17

Integral Proteins
Transmembrane Proteins

Question 18

Aren’t a part of the cell but are appendages to the surface of the cell.
Add structure to cells by binding with fibers.
Serves as attachment sites for enzymes or as cell-recognition sites.

Answer 18

Peripheral Proteins

Question 19

The movement of ions and other substances across a cellular membrane without the input of energy.
Tends to happen spontaneously and automatically.
Rate depends on the permeability of the membrane.
Movement WITH/DOWN the gradient.
Includes diffusion, facilitated diffusion, & osmosis.

Answer 19

Passive Transport

Question 20

Type of passive transport by which substances move from areas of high concentration to areas of low concentration (this process continues until the concentration becomes equal throughout a space).

Answer 20

Diffusion

Question 21

When the concentrations of a substance on either side of a selectively permeable cellular membrane are drastically different.
The relative concentration difference between a region with high concentration and a region with low concentration.
Influence the direction in which a given substance will flow.

Answer 21

Concentration Gradient

Question 22

Type of passive transport that involves transport proteins that can function as either channels or carriers.
For molecules that are too large to pass through the pores of a selectively permeable membrane or are unable to pass through the membrane due to their charge or polarity.

Answer 22

Facilitated Diffusion

Question 23

Facilitated diffusion. —> Facilitate the movement of molecules through the membrane by forming special pores/channels that are big enough to accommodate large molecules or have polarity that accepts polar or charged molecules.

Answer 23

Channel Proteins

Question 24

Facilitated diffusion. —> Embedded in the plasma membrane, these proteins bind to a substance to help molecules across the membrane.
Specific.
Proteins undergo structural changes to allow the insoluble molecules to cross the plasma membrane.

Answer 24

Carrier Proteins

Question 25

Type of passive transport. —> The diffusion of water from areas of high water concentration to areas of low water concentration.
SPECIFICALLY associated with WATER.

Answer 25

Osmosis

Question 26

Concentration of solutes within and outside of the cell is equal.
Water is moving across semipermeable membrane at an equal rate in both directions.

Answer 26

Isotonic Solution

Question 27

Concentration of solutes outside the cell is lower than the concentration of solutes inside the cell.
Water present outside the cell with move down its concentration gradient into the cell. —> May cause cell to swell/burst if this process occurs in excess.

Answer 27

Hypotonic Solution

Question 28

The concentration of solutes outside of the cell is higher than the concentration of solutes inside the cell.
Water will move down its concentration gradient out of the cell. —> Causing the cell to shrink.

Answer 28

Hypertonic Solution

Question 29

Differences in water concentration within and outside of the cell causes…
Determining force in water movement and causes water to move from areas of high concentration to areas of low concentration.

Answer 29

Osmotic Pressure

Question 30

Occurs when cells must use energy to move molecules, ions, proteins, lipids, or solutes into regions that already have a high concentration of these substances.
Uses energy to move substances AGAINST/UP their concentration gradient.
Can create chemical, electrical, or electrochemical gradient.

Answer 30

Active Transport

Question 31

There’s an electrical potential (voltage difference) between one side of a selectively permeable membrane and the other.

Answer 31

Membrane Potential

Question 32

The difference in concentration of a specific molecule, protein, or liquids on either side of a membrane.

Answer 32

Chemical Gradient

Question 33

Difference in concentration of electrical charges on either side of a membrane.

Answer 33

Electrical Gradient

Question 34

The combined effects of chemical and electrical gradients.
Both an electrical gradient and a chemical gradient have an effect on the movement of substances. —> Their effects may combine or they may negate.

Answer 34

Electrochemical Gradient

Question 35

Active transport. —> Uses ATP to move 3 sodium ions from inside to outside of the cell and 2 potassium ions from outside to inside the cell.

Answer 35

Sodium-Potassium Pump

Question 36

Steps in the Sodium-Potassium Pump:

Answer 36

1. When the pump is opened toward the inside of the cell, 3 sodium ions bind to it.
2. A molecule of ATP is split to provide the energy for active transport. —> A phosphate group from the ATP is attached to the pump.
3. Attaching the phosphate group causes the enzyme to change shape and it reorients itself to open towards the outside of the cell. The 3 sodium ions are released outside of the cell.
4. While the pump is opened to the outside of the cell, 2 potassium ions bond to the pump and the phosphate detaches.
5. Losing the phosphate group makes the enzyme return to its original shape, opened toward the inside of the cell.
6. The 2 potassium ions are released inside the cell and the cycles is ready to start over.

Question 37

1. When the pump is opened toward the inside of the cell, 3 sodium ions bind to it.
2. A molecule of ATP is split to provide the energy for active transport. —> A phosphate group from the ATP is attached to the pump.
3. Attaching the phosphate group causes the enzyme to change shape and it reorients itself to open towards the outside of the cell. The 3 sodium ions are released outside of the cell.
4. While the pump is opened to the outside of the cell, 2 potassium ions bond to the pump and the phosphate detaches.
5. Losing the phosphate group makes the enzyme return to its original shape, opened toward the inside of the cell.
6. The 2 potassium ions are released inside the cell and the cycles is ready to start over.

Answer 37

Sodium-Potassium Pump

Question 38

Bulk active transport.

Answer 38

Endocytosis

Question 39

Type of active transport (endocytosis).
The movement of food and other particles through the cell membrane.
The cell membrane encases the particle in a package (food vacuole), vacuole is moved into the cytoplasm of the cell, vacuole eventually fuses with a lysosome, and the lysosome’s enzymes break the food into usable materials for the cell.

Answer 39

Phagocytosis

Question 40

Type of active transport (endocytosis).
Occurs when the plasma membrane wraps itself around liquid outside the cello.
Dissolved molecules and ions (nonspecific). —> Everything dissolved is brought into the cell.

Answer 40

Pinocytosis

Question 41

Type of active transport (endocytosis).
Requires the recognition of the molecule by receports on the cell membrane.
These receptors point to the outside of the cell and create pits in the cell membrane. Once the receptors have filled, a signal is sent, and the pit closes off and is ingested by the cell.

Answer 41

Receptor-Mediated Endocytosis