LIPID 2

Question 1

Sphingophospholipids

Answer 1

• Lipids not containing glycerol
• composed of a sphingosine backbone
  linked to a fatty acid via an amide bond.
• many types differ in their hydrophilic attachments.
  Derivatives of ceramide, formed by esterification of a fatty acid with the amino group of sphingosine.

Question 2

types

Answer 2

Anki

Question 3

Glycosphingolipids/ Glycolipids

Answer 3

-contain both carbohydrate and lipids components.
* The precursors of both phosphorylated and glycosylated sphingolipids is ceramide.
* Essential components of all membranes in the body,but greatest amounts in nerve tissue.
* Located in the outer leaflet of plasma membrane, thus interact with ECF
* Role: Regulate cellular interactions.

Question 4

Cerebrosides

Answer 4

The simplest neutral glycosphingolipids.
* Consist of ceramide (sphingosine and FA) and a monosaccharide (Glucose or Galactose)
bound by a β-glycosidic bond to the C1.
* Found predominantly in the brain (white matter) and peripheral nervous tissue, with high concentrations in the myelin sheath.
* Functions : Provide protective coating to each nerve , Act as an insulator and Important in nerve conduction
* Galactocerebroside,common in myelin
Glucocerebroside, is primarily an intermediate in the synthesis and degradation of the more complex glycosphingolipids.

Question 5

Cerebrosides diseases

Answer 5

-Autosomal recessive disease
Accumulation of glucocerebrosides is Gaucher’s disease-b glucosidase deficiency.
b galactocerebroside accumulation - Krabbe disease.-deficient in b galactosidase.
Large spleen and liver
Affects CNS and muscle tone.
Accumulation of cerebrosides in liver and spleen causes enlargement

Question 6

Globosides

Answer 6

• Produced by attaching additional monosaccharides to a glucocerebroside.
• E.g: ceramide-glucose-galactose (AKA lactosylceramide). The additional monosaccharides can include substituted sugars such as N- acetylgalactosamine.

Question 7

Acidic Glycosphingolipids

Answer 7

• negatively charged at physiologic pH.
• negative charge is provided by N-acetylneuraminic acid ([NANA] in gangliosides, OR by sulfate groups in sulfatides.

Question 8

Gangliosides

Answer 8

• most complex glycosphingolipids
• Found primarily in the ganglion cells of the CNS, nerve endings.
• Derivatives of ceramide oligosaccharides and contain one or
  more molecules of NANA.
• Notation: G (for ganglioside) plus a subscript M, D, T, or Q to
  indicate whether there is one (mono), two (di), three (tri),
  or four (quatro) molecules of NANA in the ganglioside.

Question 9

accumulation of NANA- containing glycosphingolipids in cells.- lipid disorder

Answer 9

• The most important gangliosides present in the brain are GM1, GM2, GD, and GT
• Tay-Sachs disease : GM2 gangliosides breakdown defect.
• GM1, a more complex ganglioside derived from GM3 , is of considerable biologic interest, as it is known to be the receptor in human intestine for cholera toxin (CTX).

Question 10

Sulfatides

Answer 10

• Sulfated galactocerebrosides that are negatively charged at physiologic pH (due to sulfate group).
• found predominantly in the brain and kidneys.
• degraded in the lysosomes.
  excess can lead to pathological conditions.
• Metachromatic leukodystrophy, lysosomal storage disorder characterized by the accumulation of lysosomal sulfatides due to a deficiency in lysosomal sulfatase, arylsulfatase A.

Question 11

gaucher disease symptoms

Answer 11

• progressive neurologic symptoms
  -pulmonary involvement
  -hepatosplenomegaly
  -thrombocytopenia and anemia
• skeletal involvement

Question 12

Krabbe disease symptoms

Answer 12

• feeding difficulties
• unexpected crying
• extreme irratibility
• fever with no clear etiology
• development delays
• muscle spasms
• poor head ctrl
• frequent vomiting
• developmental regression