Question

5) (A) What is the backbone of sphingolipids? (B) What type of linkage is found between the sphinolipid backbone and a fatty acid? Is this the same type of linkage most commonly seen in other lipids? (C) What two types of linkages can be found between the sphingolipid backbone and the polar head group? (3 pts) 6) Describe primary and secondary active transport. How do these mechanisms vary from facilitate diffusion? (3 pts)

Answer 1

5). Backbone: Sphingolipids are a class of lipids containing a backbone of sphingoid bases, a set of aliphatic amino alcohols that includes sphingosine.

The sphingosine backbone is O-linked to a (usually) charged head group such as ethanolamine, serine, or choline.

Amide linkage:- The backbone is also amide-linked to an acyl group, such as a fatty acid.

No it is not the same type...

Different lipids show different type of linkages like Some Phospholipids Have Ether-Linked Fatty Acids.. Fats contain ester linkage between fatty acid and glycerol..

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Sphingolipids have a base made of a long (carbon) chain called sphingosine, which is bound with fatty acids using amide linkages to make ceramides . The sphingoid base backbone is synthesized from a long- chain fatty acyl-CoA and serine. Ceramide is the most basic sphingolipid, with only a hydrogen in the Csp-3 position and an amide- linked fatty acid. ;. More complex (phosphor)sphingolipids have headgroups attached via phosphodiester linkages, The

Sphingosine HO—3CH-CH=CH-(CH2)2-CH Fatty acid Sphingolipid (general structure) 2CH-N- H CH2–0-X Name of sphingolipid Name of X Formula of X Ceramide -H Sphingomyelin Phosphocholine -P-0-CH,—CH,—Ñ(CH3); CH_OH Neutral glycolipids Glucosylcerebroside Glucose KoH HH Ả OH OH Lactosylceramide (a globoside) Di-, tri-, or tetrasaccharide Glc Gal (Neu5AC) Ganglioside GM2 Complex oligosaccharide Gal GalNAc)

6). Primary active transport, also called direct active transport, directly uses metabolic energy to transport molecules across a membrane....

Substances that are transported across the cell membrane include metal ions, such as Na+, K+, Mg2+, and Ca2+. These charged particles require ion pumps or ion channels to cross membranes and distribute through the body...

Types of primary active transporters are:-

1. P-type ATPase: sodium potassium pump, calcium pump, proton pump
2. F-ATPase: mitochondrial ATP synthase, chloroplast ATP synthase
3. V-ATPase: vacuolar ATPase
4. ABC (ATP binding cassette) transporter: MDR, CFTR, etc.

In secondary active transport, also known as coupled transport or cotransport, energy is used to transport molecules across a membrane; however, in contrast to primary active transport, there is no direct coupling of ATP; instead it relies upon the electrochemical potential difference created by pumping ions in/out of the cell..

Eg is Electron Transport Chain in respiration...

Types of Cotransport:- Symport:- both molecules transported in same direction.. eg:- Na and Glucose cotransport in intestine...

Antiport:- in different direction.. eg. the Na+/Ca2+ exchanger, used by many cells to remove cytoplasmic calcium, exchanges one calcium ion for three sodium ions...

Uniporter Synporter Antiporter

Difference:-

This difference is that active transport needs energy, while facilitated diffusion does not need energy. The energy that active transport uses is ATP (adenosine triphosphate). When the protein changes shape in facilitated diffusion, it is because the substances bond onto the protein and the protein, because of this bond, changes it shape. This happens because the substances are going with the concentration gradient. Facilitated diffusion is needed because the substances it transports are too big to pass through the cell membrane. They want to go with the concentration gradient, but just can’t without integral proteins. With active transport, the protein changes shape by using ATP. Energy is needed in this form of transport because the substances are going against the concentration gradient. A great is example is the sodium-potassium pump (Na/K pump). This allows sodium and potassium to move against the concentration gradient...

Active Transport Passive Transport Primary Secondary Facilitated Diffusion (Uniport) Simple diffusion Uniport Cotransport Antiport Symport ADF Low P + ADP ATP High High om booooo Nom 20 An BUS NU Woo 000 High High High Pump-mediated Carrier-mediated Carrier Channel mediated mediated Free