Lipids: Structure and function of Phospholipids

Question 1

What is a hydrophilic molecule

Answer 1

A molecule
attracted to water
due to having a charge

Question 2

Thinking about it, is a hydrophilic WATER LOVING or WATER HATING?

Answer 2

Water loving

Question 3

Phospholipid is a lipid (TRUE OR FALSE?)

Answer 3

TRUE

Question 4

What is the diff between phospholipid and triglycerides?

Answer 4

One of the fatty acid molecules is replaced by a phosphate molecule in a phospholipid

Question 5

How does the joining of the phosphate group occur?

Answer 5

through a condensation reaction between hydroxyl groups on both a glycerol molecule and a phosphoric acid molecule

Question 6

what covalent bond links the phosphate molecule to the glycerol ?

Answer 6

a phosphate ester bond

Question 7

What are both the phosphate group and the glycerol together known as ? What are the fatty acid chains known as in a phospholipid molecule?

Answer 7

The head of the phospholipid
The tail of the phospholipid

Question 8

What happens when the phospholipid is surrounded by water? What is formed?

Answer 8

the hydrogen ions DISSIPATE from the phosphoric acid, forming a phosphate group with a negative charge.

Why? OH groups when losing positive hydrogen ions, leave behind negative oxygen ions and the head gains an overall negative charge

Question 9

does having a negative charge cause the molecule to become hydrophilic

Answer 9

yes

Question 10

Are fatty acid tails polar? are they charged?

Answer 10

NO,They are non polar
No, they are not charged

Question 11

What is a hydrophobic molecule?

Answer 11

a molecule repelled from water due to not having a charge

Question 12

Can phospholipids form layers on the surface of the water? how?

Answer 12

yes
the hydrophilic heads are attracted to the water and submerged and the hydrophobic heads are repelled by water

Question 13

What is the name of a
spherical monolayer of phospholipids formed?

Answer 13

micelle

Question 14

Phospholipids can also form a trilayer in cell membrane true or false?

Answer 14

false
bilayer in the cell membrane

Question 15

where can we find a phospholipid bilayer?

Answer 15

in the cell membrane

Question 16

where is the facing of hydrophilic tails and what is the facing of hydrophobic tails?

Answer 16

hydrophillic outwards
hydrophobic inwards

Question 17

what keeps the membrane fluid?
but what keeps it stable?

Answer 17

the fact that phospholipids can move and slide past each other, however they will never expose the hydrophobic tails to water which keeps the membrane stable

Question 18

Role of phospholipid bilayer

Answer 18

• electrical insulation
• control what moves in and out of the cell

Question 19

how is it an electrical insulator?

Answer 19

the inside of a bilayer has no water and does not allow water to flow, so charged ions which are always surrounded by water molecules cannot pass

Question 20

which molecules can pass through bilayer

Answer 20

small non polar molecules
ex: oxygen and carbon dioxide