General stuff (P3)

Question 1

Lipids basic principles -

Answer 1

• Non-polar
• Large complex, macromolecules
• C,H AND O

Question 2

Triglyceride formation -

Answer 2

One glycerol and 3 fatty acids. Both have a hydroxyl group, these groups lead to the formation of a water molecule

Question 3

Saturated fatty acids -

Answer 3

No double bonds present between carbon atoms, the carbon form all the maximum bonds with hydrogen atoms

Question 4

Unsaturated fatty acids -

Answer 4

Have double bonds between carbon atoms, these bonds allow the molecule to bend but no pack closely together.

Question 5

Phospholipids general principles -

Answer 5

Modified triglycerides and negatively charged being soluble in water. Contain 2 fatty acid tails and a phosphate group.

Question 6

Phosphate heads are?

Answer 6

Polar and will interact with water (hydrophilic)

Question 7

Phospholipid tails -

Answer 7

Are non-polar and are repelled by water (Hydrophobic)

Question 8

Cholesterol -

Answer 8

Sterol (alcohol) and primary in plasma membranes and it positions between the phospholipids, adds stability and fluidity, stops them becoming to fluid at higher temperatures and keep them fluid at low temperatures.

Question 9

Identifying lipids -

Answer 9

Emulsion test

Solution is mixed with ethanol

The resulting mixture is mixed with water and shaken

If remains clear it is negative but if a white emulsion forms at the top of the solution a lipid is present

Question 10

Cell membrane theory -

Answer 10

The model is known as the fluid mosaic model, as the phospholipids are free to move within the layer relative to each other, giving the membrane flexibility and as the proteins embedded in the bilayer vary in shape and size and position this is similar to a mosaic.

Question 11

Intrinsic proteins in membranes - transport across a membrane

Answer 11

Transmembrane proteins -

Channel proteins - Provide a hydrophilic channel that allows passive movement, held by hydrophobic core of membrane and hydrophobic R-groups

Carrier proteins - play a role in passive and active transport and usually involves the protein structure changing shape.

Question 12

Glycoproteins -

Answer 12

Intrinsic proteins
Embedded in the plasma membrane and play a role in cell adhesion where cells join together to form at right junctions at certain tissues and receptors for chemical signals. Resulting in a response for cell communication and signalling like neurotransmitters and hormones.

Question 13

Glycolipids -

Answer 13

Similar to glycoproteins, lipids with an attached carbohydrate chain, called antigens and can be recognised by the cells of the immune system of being self or non-self cells.

Question 14

Extrinsic proteins -

Answer 14

Present on one side of the bilayer, and have normally hydrophilic R-groups and interact with polar heads or intrinsic proteins

Cholesterol - Positions between phosphate heads has a hydrophilic end and hydrophobic end. Adds stability by making them not too rigid.

Question 15

Compartmentalisation -

Answer 15

The formation of separate membrane-bound areas. Allows specific conditions required for different cellular reactions.

Question 16

Nitrogen fixation -

Answer 16

Nitrogen gas in the atmosphere is turned into ammonia by bacteria known as rhizobium and is used by the plant which gains amino acids and the bacteria gain carbohydrates

Question 17

Ammonification -

Answer 17

When ammonia is made from dead animals (decomposers), animal waste turns into nitrogen compounds and nitrogen ions

Question 18

Nitrification -

Answer 18

When ammonia ions in the soil are changed into compounds which can be used by plants by nitrates.

Question 19

Denitrification -

Answer 19

Nitrates in the soil are made into nitrogen by denitrifying bacteria

Question 20

Hepatic portal vein -

Answer 20

Brings blood from duodenum and pancreas which are products rich in digestion.

Question 21

Bile duct -

Answer 21

Takes bile made by liver to gall bladder for storage

Question 22

Sinusoids -

Answer 22

Blood is mixed in spaces which surround hepatocytes which lead to the central vein to the hepatic vein.

Question 23

Kupfer cells -

Answer 23

Attached to the walls of sinusoids act as macrophages digest foreign particles and disease.

Question 24

Canaliculi -

Answer 24

Space where the bile broken down by the hepatocytes move and from these into bile ducts and gall bladder.

Question 25

Deamination -

Answer 25

AA contain nitrogen and cant be usually stored so are broken down and excreted. Removal of the amine group of NH2 to ammonia of NH3 which is toxic and undergoes the ornithine cycle, where it combines with carbon dioxide in the mitochondria to make urea. Released and goes into the blood and remove by the kidneys.

Question 26

Detoxification in liver -

Answer 26

Takes sites of toxins such as drugs and alcohol and make them less harmful. E.g Ethanol is broken down by the enzyme alcohol dehydrogenase into ethanal for cellular respiration.