Bio Test #1

Question 1

Homeostasis

Answer 1

The maintenance of constant conditions in the internal environment of and organism

Question 2

What it the most important part in maintaining homeostasis?

Answer 2

Our cells because without proper cell functions, the body starts to shut down normal homeostatic mechanisms

Question 3

Receptor

Answer 3

Detects any deviations from the set point and signals the change to the control centre along a neuron

Question 4

Effector

Answer 4

Receives a signal from the control centre and causes a change to restore the set point

Question 5

Control centre

Answer 5

Interprets the signal form the receptor and signals to the effector along a neuron

Question 6

Set point

Answer 6

The normal homeostatic range (37C)

Question 7

Negative feedback

Answer 7

Loops are used to control neostatic systems within a narrow range of set points

Question 8

What do cells need to do to maintain homeostasis?

Answer 8

1. Obtain food
2. Convert energy
3. Eliminate wastes
4. Reproduce
5. Grow and repair itself
6. Transport substances

Question 9

Fluid mosaic model

Answer 9

Model for the cells plasma membrane

Question 10

What is plasma membrane made of?

Answer 10

2 layers of phospholipids

Question 11

Passive transport

Answer 11

• Materials move from an area of high concentration to an area of low concentration.
• The materials move with the concentration gradient and does not require energy

Question 12

Diffusion

Answer 12

Materials move from an area of high concentration to an area of low concentration

• in the cell materials will move across the membrane through specialized pores in the cell membrane

Question 13

Osmosis

Answer 13

Water molecules that move across a selectively permeable membrane from an area of high concentration to low concentration

• water will move across the membrane through specialized pores

Question 14

3 possible concentrations for a solution

Answer 14

1. Isotonic
2. Hypertonic
3. Hypotonic

Question 15

Isotonic

Answer 15

A solution with a concentration equal to the cell

Question 16

Hypertonic

Answer 16

A solution with a high concentration

• has high osmotic pressure
• more solute than water

Question 17

Hypotonic

Answer 17

A solution with a low concentration

• Has low osmotic pressure
• Less solute than water

Question 18

Facilitated diffusion

Answer 18

When materials move from an area of high concentration to low concentration but requires the assistance of specialized carrier proteins in the plasma membrane.
Eg.) glucose

Question 19

Active transport

Answer 19

Materials move from an area of low concentration to and area of high concentration. Movement is against the concentration gradient. The cell must use energy in the form of ATP to move the materials

Question 20

Carrier proteins

Answer 20

Can move materials across the membrane AGAINST the concentration gradient

Question 21

Endocytosis

Answer 21

Materials are engulfed by the cell and become enclosed in infoldings of the plasma membrane that eventually form vacuoles

Question 22

2 forms of endocytosis

Answer 22

• Pinocytosis

- Phagocytosis

Question 23

Pinocytosis

Answer 23

Small amounts of liquid brought in

Question 24

Phagocytosis

Answer 24

Solid particles are ingested into the cell

Question 25

Exocytosis

Answer 25

A vacuole of materials will fuse with the plasma membrane forcing contents from the cell

Question 26

Factors that influence the movement of substances across a membrane:

Answer 26

• size of molecule
• concentration gradient
• temperature
• charge of molecules
• surface area

Question 27

Thermoregulation

Answer 27

The ability to maintain a constant temperature

Question 28

Osmoregulation

Answer 28

An internal balance between water and dissolved materials

Question 29

Why is the model for the cells membrane called THE FLUID MOSAIC MODEL?

Answer 29

The plasma membrane is said to be fluid because components of the membrane can move around sideways and can rearrange itself to suit the task.

-mosaic means it’s made up of many different parts

Question 30

How are phospholipids arranged so that water doesn’t seep through the walls of the cell?

Answer 30

There are 2 layers of phospholipids,

• hydrophilic phospholipid head (water loving)
• hydrophobic fatty acid tail (water hating)