Tag: biomolecules: chemical constituents of living cells

Quizzes (7) Questions (113)

Questions Related to biomolecules: chemical constituents of living cells

Multiple choice bio-chemistry lipids derived lipids biomolecules: chemical constituents of living cells cell membrane

Cholesterol belongs to which of the following groups

  1. Steroids

  2. Neutral fats

  3. Waxes

  4. Phospholipids
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The steroids are composed of seventeen carbon atoms, bonded in four fused rings: three six-membered cyclohexane rings and one five-membered cyclopentane ring. The steroids differ in the functional group attached to this four-ring core and by the oxidation state of the ring.

Steroids such as cholestrol decrease membrane fluidity. Like lipids, these are highly concentrated energy stores. They are normally metabolized and excreted.
So, the correct option is 'Steroids'.

Multiple choice bio-chemistry lipids derived lipids biomolecules: chemical constituents of living cells cell membrane

Which one of the following is not a correct statement regarding the design of biological membranes?

  1. Carbohydrate molecules associated with membranes tend to be associated with protein molecules embedded in the membrane

  2. Hydrophobic ends of phospholipid molecules in the outer monolayer of the membrane are exposed directly to the extracellular environment

  3. Cholesterol is a type of lipid frequently found in membranes of animal cells

  4. Protein molecules can be located on the inner and outer surfaces of the membrane as well as traverse the entire thickness of the bilayer
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
In a cell membrane, the hydrophobic ends of phospholipid molecules in the outer monolayer of the membrane are sandwiched between the hydrophilic heads of the phospholipid bilayer and are not exposed to the extracellular environment.

So, the correct answer is 'Hydrophobic ends of phospholipid molecules in the outer monolayer of the membrane are exposed directly to the extracellular environment'.
Multiple choice bio-chemistry lipids derived lipids biomolecules: chemical constituents of living cells cell membrane

In the fluid mosaic membrane model, the phospholipid bilayer

  1. Is sandwiched between two protein layers

  2. Is covered by a single protein layer

  3. Has proteins embedded in it

  4. Lies on top of a single protein layer
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In the fluid mosaic model, the phospholipid bilayer has integrated as well as peripheral proteins embedded in it. The integrated proteins are found on the inside and span across the bilayer, while the peripheral proteins are found at the periphery of the lipid layers.

So the correct answer is 'has proteins embedded in it'.

Multiple choice bio-chemistry lipids derived lipids biomolecules: chemical constituents of living cells cell membrane

Function of smooth endoplasmic reticulum is?

  1. Synthesis of lipid

  2. Synthesis of minerals

  3. Synthesis of protein

  4. None
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Its main functions are the synthesis of lipids, steroid hormones, the detoxification of harmful metabolic byproducts and the storage and metabolism of calcium ions within the cell. The smooth ER is distinguished from the other parts of the endoplasmic reticulum by the absence of membrane-bound ribosomes.

Thus A is the correct option. 

Multiple choice bio-chemistry lipids derived lipids biomolecules: chemical constituents of living cells cell membrane

CPPP which is the important component of sterol is mainly stood for?

  1. Cyclopentanoperhydrophenanthrene

  2. Pentanoperhydrophenanthrene

  3. Cycloperhydrophenanthrene

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

CPPP is the abbreviated form of Cyclopentanoperhydrophenanthrene. It is an important component of sterol. Thus the correct answer is option A.

Multiple choice bio-chemistry lipids derived lipids biomolecules: chemical constituents of living cells cell membrane

Steroids are

  1. Tetraterpenes

  2. Polyterpenes

  3. Triterpenes and their derivative

  4. Phenolic compounds
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Steroids are hormonal substances in animals, but they are components of membranes in most organisms. Triterpenes are precursors to steroids in both plants and animals. Steroids are derivatives of triterpenes with 26 or more carbon atoms that have undergone a characteristic type of rearrangement. So, the correct answer is option C.