Lipids

Question 1

What are the 3 major classes of lipids stating examples.

Answer 1

1. simple (fats like triglycerides, waxes)
2. compllex (ex: phospholipids, sphingolipids/glycolipids, lipoproteins)
3. derived (ex: fatty acids, glycelrol, steroids, ketone bodies)

Question 2

What is a complex lipid?

Answer 2

An ester of a fatty acid containing an alcohol, fatty acid, and other groups.

Question 3

Define a simple lipid.

Answer 3

An ester of a fatty acid which upon hydrolysis yields an alcohol (usually glycerol) and fatty acid(s)

Question 4

State the 5 types of lipoprotein complexes in the human body.

Answer 4

1. LDL
2. VLDL
3. HDL
4. Chylomicrons
5. IDL (intermediate density lipoproteins)

Question 5

What is an apolipoprotein?

Answer 5

The protein that binds to lipids on the lipoprotein complex membrane.

Question 6

State 3 components of the lipoprotein complex membrane.

Answer 6

apolipoproteins
cholesterol
phospholipids

Question 7

Prostaglandins are produced from which unsaturated fatty acid?

Answer 7

Arachidonic acid

Question 8

4 symptoms of essential fatty acids (EFAs) include

Answer 8

1. intellectual disability in children
2. thromocytopenia (poor wound healing)
3. alopecia (hair loss due to autoimmune attack)
4. phrynoderma (toad skin)

Question 9

Which saturated fatty acid contributes least to fat storage?

Answer 9

Lauric acid

Question 10

Which phospholipid is only found in mitochondria?

Answer 10

Phosphatidic acid

Question 11

Why is phosphatidic acid essential to mitochondrial functioning?

Answer 11

It is a precursor of phosphatidyl glycerol which is also a precursor of cardiolipin. Low levels of cardiolipin result in mitochondrial disfunction; heart failure, hypothyroidism, and Cardioskeletal myopathy

Question 12

What is the function of phosphatidyl inositol?

Answer 12

Involved in second messenger system in cell signaling; by cleaving into DAG and IP3

Question 13

What is the most abundant phospholipid on the cell membrane?

Answer 13

Phosphatidyl choline

Question 14

State 3 functions of sphingomyelin.

Answer 14

1. Cytokinesis (contains domains for binding actin filaments to contract cell)
2. Apoptosis (hydrolysis signals cell death)
3. Affects cholestrol distribution on plasma membrane (as it forms strong bonds with cholestrol)

Question 15

Which sphingolipid is the most abundant in myelin sheath?

Answer 15

Cerebrosides

Question 16

How are cerebrosides involved in Gaucher’s disease?

Answer 16

Caused by excess deposition of glucocerebrosides on myelin sheath and in phagocytic cells, due to lack or malfunction of the enzyme; glucocerebrosidase

Question 17

What is Gaucher’s disease?

Answer 17

Autosomal recessive condition in which glucocerebrosidase is deficient causing accumulation of glucocerebrosides on myelin sheaths and in phagocytic cells

Question 18

Which sphingolipid is involved in formation of blood groups ABO?

Answer 18

Gangliocides

Question 19

Which molecule is the precursor of steroids?

Answer 19

cholesterol

Question 20

State 3 functions of steroids.

Answer 20

1. regulate metabolism
2. immune response
3. reproduction

Question 21

Which cells in the body don’t contain cholesterol?

Answer 21

Nervous tissue