The following reaction depicts the activity of a particular class of enzymes:
Substrate E → Product
A compound containing adjacent carbon atoms bearing X and Y groups is converted into X–Y and a compound containing a C=C double bond.
Identify the enzyme class E from the following options:
Lyases catalyse the removal of groups from substrates without hydrolysis, often resulting in the formation of double bonds.
Streptokinase is used as a clot buster, statins lower blood cholesterol, lipases are used in detergent formulations and Cyclosporin A is an immunosuppressive agent.
Select the correct statements regarding cell membrane in eukaryotic cell.
(A) Membrane of human RBCs has approximately 52% protein.
(B) Major phospholipids are arranged in a bilayer.
(C) Extensions of the plasma membrane into the cell form mesosomes.
(D) Tails towards the inner part of lipids are hydrophobic and thus protected from aqueous medium.
(E) Glycocalyx is present on the outer surface of the plasma membrane.
Choose the correct answer from the options given below:
Human RBC membrane contains about 52% protein. Phospholipids form a bilayer with hydrophobic tails inward, glycocalyx is present externally, whereas mesosomes are found only in prokaryotes.
Choose the correct statements regarding cell organelles and their inclusions.
(A) The endomembrane system includes Golgi complex, endoplasmic reticulum and mitochondria.
(B) Rough endoplasmic reticulum bears ribosomes on its surface.
(C) Both mitochondria and plastids have circular DNA.
(D) A network of microtubules, microfilaments and intermediate filaments present in the cytoplasm is called cytoskeleton.
(E) Mitochondrion is a single membrane-bound structure.
Choose the correct answer from the options given below:
RER bears ribosomes, mitochondria and plastids possess circular DNA, and the cytoskeleton is formed by microtubules, microfilaments and intermediate filaments. Mitochondria are double membrane-bound and are not part of the endomembrane system.
The toxin proteins isolated from Bacillus thuringiensis, coded by which of the following genes would control cotton bollworms and corn borer, respectively?
The cryIAc gene is effective against cotton bollworms, whereas the cryIAb gene is effective against corn borer.
Which of the following floral formula is the correct
floral formula of Solanaceae family ?
AI-generated explanation. Check against your textbook.
Explanation:
The floral formula of Solanaceae (e.g., potato, tomato) in NCERT is pentamerous and gamopetalous with a superior, syncarpous ovary. The standard formula is K5 C5 A5 G(5) — 5 sepals (calyx), 5 petals fused into a tube (corolla), 5 stamens, and a 5-celled syncarpous ovary. Thus, option 3 is correct.
🧠 Did You Know?
Solanaceae flowers are usually regular and zygomorphic in some genera, but NCERT describes the common pentamerous, actinomorphic flowers with fused corolla in this family.
💡 NCERT Memory Line:
Solanaceae: K5 C5 A5 G(5) – pentamerous, fusion in corolla, superior syncarpous ovary.
