Tag: bio-chemistry

Questions Related to bio-chemistry

Cholesterol belongs to which of the following groups

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

  1. Steroids

  2. Neutral fats

  3. Waxes

  4. Phospholipids

Show answer
Correct Option: A
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'.

Which one of the following is not correctly matched?

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

  1. Cutin- Consists of long chain fatty acids and polyhydroxy derivatives of these fatty acids

  2. Pectin-Methylated polymer of flacturonic acid

  3. Lignin- Formed by condensation on coniferyl alcohol

  4. Callose- Glycosylated aliphatic acid

Show answer
Correct Option: A

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

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

  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

Show answer
Correct Option: B
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'.

In the fluid mosaic membrane model, the phospholipid bilayer

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

  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

Show answer
Correct Option: C
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'.

Function of smooth endoplasmic reticulum is?

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

  1. Synthesis of lipid

  2. Synthesis of minerals

  3. Synthesis of protein

  4. None

Show answer
Correct Option: A
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. 

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

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

  1. Cyclopentanoperhydrophenanthrene

  2. Pentanoperhydrophenanthrene

  3. Cycloperhydrophenanthrene

  4. None of the above

Show answer
Correct Option: A
Explanation:

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

Select the correct option:

Lecithin is a 

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

  1. Sterol

  2. Glycolipid

  3. Phospholipid

  4. Sphingolipid

Show answer
Correct Option: C
Explanation:

Phospholipids are triglyceride lipids, in which one fatty acid is replaced by phosphoric acid residue often linked to additional nitrogenous group,eg., choline in lecithin.

So, the correxct answer is 'Phospholipid'.

Steroids are

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

  1. Tetraterpenes

  2. Polyterpenes

  3. Triterpenes and their derivative

  4. Phenolic compounds

Show answer
Correct Option: C
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.

Two important processes in a cell, which take place outside the membrane bound organelles, are

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

  1. Enzyme synthesis and DNA replication

  2. Nucleotide synthesis and mutation

  3. Fatty acid synthesis and spindle assembly

  4. Glycolysis and photophosphorylation

Show answer
Correct Option: C
Explanation:
The process of fatty acid synthesis takes place in the cytoplasm and not in a membrane-bound organelle. Also, spindle assembly takes place in the centrioles which also lack a membrane.

So, the correct answer is 'fatty acid synthesis and spindle assembly'.

Mark the statement which is not a significant application of centrifugation.

bio-chemistry biochemical techniques centrifugation separation techniques separation of matter

  1. Used in squeezing clothes in washing machines

  2. Used for seperating cream from milk

  3. Used in laboratories for testing blood/urine

  4. All of the above are application of centrifugation

Show answer
Correct Option: D
Explanation:

The particles which are very small and can easily pass through can be separated by centrifugation. In this, the denser particles settle down and the lighter particles stay at the top.
Hence, all the options are the applications of centrifugation. In this method, suspended particles is rotated at a high speed in a centrifuge.