Lipids and Membranes

Question 1

What is the reaction type between a fatty acid and glycerol molecule?

Answer 1

Condensation reaction

Question 2

What is the bond formed between a fatty acid and glycerol?

Answer 2

Ester bond

Question 3

What are the 3 roles of triglycerides?

Answer 3

Storage, insulation, protection

Question 4

how do the structure and properties of triglycerides relate to their function?

Answer 4

1. High ratio of energy storing bonds to C atoms
2. Low mass to energy ratio
3. No osmotic affect on the water potential in cells

Question 5

what it the difference between triglycerides and a phospholipid?

Answer 5

A fatty acid group is substituted for a phosphate group in a phospholipid

Question 6

What are the 3 functions of the plasma membrane?

Answer 6

1. Control transport through a partially permeable membrane
2. Act as a receptor site
3. Separate cell from outside environment

Question 7

What molecules do partially permeable membranes not let through?

Answer 7

Water soluble molecules, charged molecules, polar molecules

Question 8

What are the 2 types of protein found in the membrane?

Answer 8

Extrinsic (in one layer)

Intrinsic (crosses the whole membrane)

Question 9

What are some examples of polar molecule which need to cross the membrane?

Answer 9

Ions and Glucose

Question 10

What is the name given to the carbohydrates attached to the proteins in the membrane?

Answer 10

Glycoproteins

Question 11

What is the function of glycoproteins?

Answer 11

They allow for extra functions in the proteins embedded in the membrane

Question 12

what is the function of a glycolipid?

Answer 12

Act as recognision sites and maintain the stability of the membrane
Allow cells to attach to one another and thereby form tissues

Question 13

What is the function of cholesterol in the membrane?

Answer 13

Increase strength and stability by restricting movement of other molecules in the membrane.

Question 14

Why is the plasma membrane described as fluid mosaic?

Answer 14

Fluid- molecules can move around

mosaic- different types of molecule associated with the membrane

Question 15

What can the molecules in the fluid mosaic model do?

Answer 15

Move sideways, leave and join membranes

Question 16

What is Fick’s law?

Answer 16

Rate of diffusion is proprtional to :

[SA x Difference in Conc]/ Membrane thickness

Question 17

what are some features of facilitated diffusion?

Answer 17

Specific
Works down a conc gradient
Limited by number of channel proteins
Passive 
Used to transport charged, polar or hydrophillic substances

Question 18

which substances required channel proteins to cross the membrane?

Answer 18

Ions

Question 19

What is the definition of osmosis?

Answer 19

The movement of water across a partially permeable membrane down a water potential gradient.

Question 20

What is crenation?

Answer 20

When water leaves the cell by osmosis and shrinks

Question 21

What are some examples of active transport?

Answer 21

Uptake of glucose and amino acids in the small intestine
Absorption of mineral ions in plant roots
Exchange of sodium and potassium in neurons