FREE NEET Biology Practice MCQ Test: Biomolecules Exercise 2 Questions Answers With Detailed Explanations [PDF]

Answer: (d)

Answer: (d)

Amino acids are mostly synthesized from α-ketoglutaric acid. These are the precursors of amino acids. A five carbon compound formed during Krebs' cycle is a α-ketoglutaric acid which is the first dicarboxylic acid formed. Pyruvic acid converted into alanine, α-ketoglutaric acid into glutamic acid, OAA into aspartic acid, polymerization of such amino acids results into formation of proteins.

Answer: (c)

Phosphorus is present in plasma membrane in the form of phospholipid bilayer. It is an essential component of all nucleic acids not 'certain' nucleic acids. Moreover, phosphorus is never found in proteins.

Answer: (b)

All those sugars which have free aldehyde or ketone group are called reducing sugars. These are able to reduce cupric ions ($Cu^{+2}$) into cuprous ions ($Cu^{+}$). Sucrose, starch are non-reducing sugars.

Answer: (a)

Basic amino acids have an additional amino group without forming amides, thus they are diamino monocarboxylic acids e.g., arginine, lysine, etc.

Answer: (d)

Nitrogen bases are heterocyclic compounds. Length of one turn of DNA is 34Å.

Answer: (b)

Some bacteria (such as Rhodopseudomonas), algae and green plant cells produce carbohydrates.

Answer: (d)

Phospholipids are composed of phosphate group and one or more fatty acids. They have hydrophilic (polar) phosphate group and long hydrophobic (non-polar) hydrocarbon ‘tails’. The phospholipids readily form membrane-like structures in water.

Answer: (a)

In polysaccharides, individual monosaccharide is linked by glycosidic bond. This bond is formed between two carbon atoms of two adjacent monosaccharides. A glycosidic bond is a type of covalent bond that joins a carbohydrate (sugar) molecule to another group, which may or may not be another carbohydrate. Glycosidic bonds are formed by dehydration.

Answer: (d)

Answer: (a)

Answer: (c)

Answer: (b)

Various mineral elements present in living organisms include (i) major minerals (macro minerals)- Calcium (Ca), Chlorine (Cl), Magnesium (Mg), Phosphorus (P), Sodium (Na), Potassium (K), Sulphur (S) and (ii) trace minerals (micro minerals)- Chromium (Cr), Cobalt (Co), Copper (Cu), Fluorine (F), Iodine (I), Iron (Fe), Manganese (Mn), Molybdenum (Mo), Selenium (Se) and Zinc (Zn).

Answer: (d)

Coenzyme is an organic substance that enhances the action of an enzyme by binding with the protein molecule.

Answer: (a)

Answer: (c)

Answer: (d)

According to Chargaff's rules, the amount of adenine is always equal to that of thymine, and the amount of guanine is always equal to that of cytosine i.e., A = T (120) and G = C (120), therefore, the total no. of nucleotides would be 120 × 4 = 480.

Answer: (a)

Answer: (c)

Nucleotides are the building blocks of nucleic acid (DNA and RNA), therefore the information in a genetic nucleic acid resides in the sequences of nucleotide. The biological functions of nucleotides are: storage of data (as part of DNA/RNA); energy currency (ATP); cellular communication (cAMP; ATP allosteric regulator) and co-enzyme catalysis.

Answer: (c)