study guide - unit two concept 2

Question 1

Homeostasis

Answer 1

-Need of an organism to stay stable by regulating internal conditions

Question 2

Solute

Answer 2

-What gets dissolved

Question 3

Solvent

Answer 3

-What does the dissolving

Question 4

Solution

Answer 4

-Uniform mixture of two or more substances

Question 5

Concentration

Answer 5

-Amount of solute dissolved in solvent

Question 6

Concentration gradient

Answer 6

-Difference in concentration of a substance from one location to another

Question 7

Phagocytosis

Answer 7

Cell “eating”; when the cell engulfs solids into a vesicle and breaks them down

Question 8

Pinocytosis

Answer 8

Cell “drinking”; when the cell engulfs liquids into a vesicle and breaks them down

Question 9

Differentiate between dynamic and static equilibrium with regards to homeostasis.

Answer 9

A static equilibrium would be constant and unchanging.

A dynamic equilibrium fluctuates above and below the constant state, but the overall rate of “loss” balances out with the overall rate of “gain”.

Question 10

Describe the relationship between response to stimuli and homeostasis.

Answer 10

Organisms are designed to take in different stimuli, communicate the messages of those stimuli, and then initiate a response.
This is how homeostasis, or constant internal stability, is maintained.

Question 11

Differentiate between positive and negative feedback loops. Include two examples of each.

Answer 11

Positive feedback loop – the output of a system intensifies the response, leading to amplification
Ex. Hormones released in human child birth and fruit ripening

Negative feedback loop – the output of a system causes a counter response to return to a set point, leading to stabilization
Ex. Thermoregulation and osmoregulation

Question 12

Explain the role of the cell membrane in maintaining homeostasis on a cellular level. Include which substances can and cannot pass through easily.

Answer 12

Cells maintain homeostasis with highly regulated transport mechanisms.
The selective permeability of the cell membrane allows the cell to control what moves in and out as it brings needed resources in, expels waste, and transports signals in and out of the cell to maintain constant and stable internal conditions.

Small, nonpolar, hydrophobic and/or neutral substances can pass easily
Polar and/or large molecules cannot pass easily

Question 13

Differentiate between passive and active transport.

Answer 13

Passive – requires no extra energy as substances move down the concentration gradient from [high] 🡪 [low]

Active – requires extra energy as substances move against the concentration gradient from [low] 🡪 [high]

Question 14

Simple diffusion and list examples

Answer 14

the spreading out of molecules across a membrane until equilibrium is reached.
net movement of molecules from [high] 🡪 [low]; Ex. O2 and CO2

Question 15

Facilitated diffusion with examples

Answer 15

uses a transport proteins to aid in the movement of molecules from [high] 🡪 [low];

helps to facilitate the diffusion of molecules that normally couldn’t pass through the cell membrane.

Ex. Polar molecules like Ca+2 and large molecules like glucose

Question 16

Osmosis with example

Answer 16

diffusion of water from [high] 🡪 [low]; Ex. Water

Question 17

Molecular Pump

Answer 17

uses energy to pump molecules across the membrane against the concentration gradient
through a protein pannel
low to high

Question 18

Endocytosis

Answer 18

Endocytosis: uses energy and vesicles to move particles into the cell; Ex. White blood cells engulf bacteria for destruction

Question 19

Exocytosis

Answer 19

Exocytosis: uses energy and vesicles to move particles out of the cell; Ex. Neurons secrete neurotransmitters for signaling

Question 20

Explain the difference between hypotonic, isotonic, and hypertonic solutions. You may use a picture to help you describe.

Answer 20

hypo: water concentration is higher than the cells cytoplasm
hyper: water concentration is lower than the cells cytoplasm
isotonic: is identical water concentration to cells cytoplasm.

if a solution is hypertonic to a hypotonic cell, then the cell will shrivel.
if a solution is hypotonic to a hypertonic cell then the cell will swell