Lipid Structure and Functions

What is the characteristic of amphipathic molecules?

With hydrophilic tails attached to non-polar head groups
With hydrophilic tails attached to polar or charged head groups
With hydrophobic tails attached to non-polar head groups
With hydrophobic tails attached to polar or charged head groups (correct)

What is the structural component of sphingolipids?

Serine and fatty acid palmitate
Cholesterol and serine
Sphingosine and fatty acid palmitate (correct)
Sphingosine and cholesterol

What is the function of ubiquinone in the mitochondrial membrane?

It is involved in the synthesis of steroid hormones
It is involved in the formation of bilayers
It functions in conjunction with enzymes in cellular respiration (correct)
It is involved in the regulation of calcium absorption

What is the main source of vitamin A?

Plant pigments such as b-carotene (B) Signup and view all the answers

What is the result of vitamin D stimulation in the intestine?

Stimulation of calcium absorption in the intestine (B) Signup and view all the answers

What is the common characteristic of vitamins A, D, E, and K?

They are all isoprenoids that perform a variety of physiological roles (C) Signup and view all the answers

What is the primary function of Vitamin E in the body?

Suppressing free radical formation (C) Signup and view all the answers

What is the primary function of Vitamin K in the body?

Participating in the enzymatic carboxylation of Glu residues (A) Signup and view all the answers

What is the function of waxes produced by plants?

Preventing water loss (B) Signup and view all the answers

Which of the following lipids is known for its 'hot' taste?

Capsaicin (A) Signup and view all the answers

Which of the following lipids is used therapeutically as a pain reliever?

Capsaicin (C) Signup and view all the answers

What is the common characteristic of Vitamins A, D, E, and K?

They are all isoprenoids (D) Signup and view all the answers

What is the main reason for the maintenance of lipid asymmetry in membranes?

Slow rate of diffusion between leaflets (D) Signup and view all the answers

What is the characteristic of amino acids found in a transmembrane helix?

Highly hydrophobic (C) Signup and view all the answers

What is the term for the movement of lipids within one leaflet?

Lateral diffusion (A) Signup and view all the answers

What is the function of translocases or flippases?

To move lipids between leaflets (B) Signup and view all the answers

What is the characteristic of longer acyl chains in lipids?

Less mobile (C) Signup and view all the answers

What is the characteristic of saturated acyl chains in lipids?

Less mobile (A) Signup and view all the answers

What is the function of bacteriorhodopsin in Halobacteria?

To capture light energy and move protons across the membrane (B) Signup and view all the answers

What is the main function of the β-barrel structure in membranes?

To allow small molecules to diffuse across the membrane (C) Signup and view all the answers

What is the characteristic of lipid-linked proteins in membranes?

They are anchored in the lipid bilayer by a covalently attached lipid group (B) Signup and view all the answers

What is the fluid mosaic model of membrane structure?

A model of membrane protein diffusion (C) Signup and view all the answers

What is the role of highly polar residues in integral membrane proteins?

To mark the point where the polypeptide leaves the membrane (A) Signup and view all the answers

What can limit the mobility of proteins in the membrane?

Their interaction with cytoskeletal proteins (A) Signup and view all the answers

What type of protein moves a single substance at a time?

Uniporter (A) Signup and view all the answers

What is the direction of movement of sodium ions through a symport protein?

Into the cell (B) Signup and view all the answers

What is the purpose of the Na,K-ATPase pump in the cell?

To establish a concentration gradient of sodium and potassium ions (D) Signup and view all the answers

What is the direction of movement of glucose through a uniport protein?

Out of the cell (A) Signup and view all the answers

What is the energy source for the transport of Na+ and K+ ions?

The reaction of converting ATP to ADP + Pi (A) Signup and view all the answers

What is the result of secondary active transport?

Transport of molecules against their concentration gradient (C) Signup and view all the answers