Crossing the plasma membrane

Question 1

Function of triglycerides (EPTTFA)

Answer 1

• Energy source
• Protection of vital organs
• To prevent evaporation in plants
• To insulate body
• Forms myelin sheath
• As a water source

Question 2

Elements in lipid (CHO)

Answer 2

Carbon, hydrogen, oxygen

Question 3

Elements in phospholipid (CHOP)

Answer 3

Carbon, hydrogen, oxygen, phosphorus

Question 4

Cholesterol

Answer 4

Provides stability and flexibility to the membrane

Question 5

Glycoproteins and glycolipids

Answer 5

Carbohydrate chain attached to either a protein or phospholipid.

Often have roles in cell communication eg. antigens

Question 6

Diffusion

Answer 6

The net movement of particles from a high concentration to a low concentration, down a concentration gradient

Question 7

Substances that can cross directly through the phospholipid bilayer

Answer 7

• Small gases eg. O2/Co2
• Small non-polar molecules eg. Urea, ethanol
• Lipid soluble molecules eg. vitamin D
• THE EXEPTION - Water (polar but very small)

Question 8

Is diffusion active or passive?

Answer 8

Diffusion is PASSIVE.

This means it requires no energy from respiration.

Question 9

Osmosis

Answer 9

The net movement of water molecules from a high concentration, through a partially permeable membrane, to a low concentration of water molecules

Question 10

Is osmosis active or passive?

Answer 10

Like diffusion, osmosis is a passive process – it requires no energy from respiration and can occur in the absence of cells – as long as a partially permeable membrane is present

Question 11

Hypotonic

Answer 11

Solution that is lower in solute and higher in water molecules
Water always moves from hypotonic to hypertonic

Question 12

Hypertonic

Answer 12

Solution that is higher in solute and lower in water molecules

Question 13

Isotonic

Answer 13

When two solutions are of EQUAL solute concentration.

There will be no net movement of water between two solutions.

Question 14

Osmosis scaffold - 5 steps

red blood cell example

Answer 14

1. Osmosis has occurred.
2. Water has moved FROM the hypotonic distilled water outside the (red blood cell),
3. THROUGH the (red blood cell) plasma membrane,
4. TO the hypertonic cytosol of the (red blood cell).
5. The (red blood cell) swells and then lyses.

Question 15

Facilitated Diffusion

Answer 15

The diffusion of particles across a membrane using a protein channel

Required for particles that are too large or too polar/charged/hydrophilic to cross the phospholipid bilayer eg. glucose/amino acids

Question 16

Active Transport

Answer 16

The movement of dissolved substances across a membrane from a low to a high concentration using ATP and a protein pump.
Required for large, hydrophilic and polar molecules

Question 17

Bulk Transport - Exocytosis

Answer 17

Bulk movement of large molecules OUT of the cell.

This is primarily proteins but can be other polymers or molecules too big to pass through a protein pump or channel.

Vesicles fuse with the cell membrane and expel their contents outside of the cell eg. release of hormones in endocrine glands.

Question 18

Endocytosis

Answer 18

Bulk movement of large molecules INTO the cells.

The substances hit the cell membrane triggering the formation of a vesicle inside the cell.

There are two types of endocytosis – pinocytosis and phagocytosis.

Question 19

Pinocytosis

Answer 19

Bulk movement of liquids, into the cell.

Question 20

Phagocytosis

Answer 20

Bulk movement of solids into the cell eg. White blood cells engulf bacteria.

Question 21

Collection method scaffold

Answer 21

1. There will be two groups
2. In the experimental group (IV) will be changed by ….
3. Add …
4. Add…
5. Add…
6. The (DV) will be measured by … All other variables will be kept the same e.g. …
7. Repeat the above for the other (IV’s)
8. For the control group repeat the above but with no ….
9. Repeat the experiment at least 5 times
10. If …. then …