Q.What is present on the surface of the leaves which helps the plant prevent loss of water but is absent in roots?

The question asks about a microbody — a small, membrane-bound organelle — that handles two jobs: catabolising (breaking down) long-chain fatty acids and helping make phospholipids. The key is to match each organelle’s known functions to these tasks.

1. Peroxisomes are the classic site of β-oxidation of very long-chain fatty acids (VLCFAs). In animal cells, this is a major peroxisomal function; in plant cells, peroxisomes also break down fatty acids (especially in germinating seeds). They also contain enzymes for ether-phospholipid synthesis (like plasmalogens), which is a key part of phospholipid production. So peroxisomes fit both criteria.

2. Glyoxysomes are a special type of peroxisome found in plant seeds. They do break down fatty acids (via the glyoxylate cycle) to produce sugars, but they are not generally involved in phospholipid synthesis in the way the question implies. They are a subset, not the general answer.

3. Sphaerosomes (also called oleosomes) are lipid-storage organelles in plant cells. They store fats but do not catabolise them or synthesise phospholipids — they are just fat droplets. …

Peroxisomes are small, membrane-bound organelles found in the cytoplasm of eukaryotic cells. They are crucial for various metabolic reactions, particularly those involving the breakdown of certain molecules and detoxification. Their functions often involve oxidative reactions, which produce hydrogen peroxide, a toxic byproduct, which they then neutralize. Understanding these core functions helps in identifying what they do not do.

Here's a breakdown of each option:

1. Analyze Option (A) Synthesis of glycolipids:

   Glycolipids are lipids with a carbohydrate attached. Their synthesis primarily occurs in the endoplasmic reticulum and the Golgi apparatus, where enzymes add carbohydrate groups to lipid precursors. Peroxisomes are not known to play a direct role in the synthesis of glycolipids. While peroxisomes are involved in lipid metabolism, their role is more focused on the breakdown of specific lipids and the synthesis of certain specialized lipids like plasmalogens, not general glycolipid synthesis.

2. Analyze Option (B) Catabolism of long chain fatty acids:

   This is a well-established and significant function of peroxisomes. They are responsible for the $\beta$-oxidation of very long-chain fatty acids (VLCFAs) and branched-chain fatty acids. In animal cells, while mitochondria also perform $\beta$-oxidation, peroxisomes are essential for the initial breakdown of VLCFAs before they can be further processed in mitochondria. In plants and yeast, peroxisomes are the primary site for all $\beta$-oxidation.

   Fatty acid + $O_2 \xrightarrow{\text{Peroxisomal enzymes}}$ Acetyl-CoA + $H_2O_2$

3. Analyze Option (C) Role in photorespiration: …

Checking each statement:

• (A) Peroxisomes participate in photorespiration — correct; the glycolate/photorespiratory pathway involves peroxisomes.
• (B) "Lysosomes perform glycolate cycle" — wrong; the glycolate cycle occurs in peroxisomes (with chloroplasts and mitochondria). Lysosomes contain hydrolytic enzymes for intracellular digestion. …

Understanding the Question

We're given four statements pairing cellular structures with their characteristics. Our task is to identify which statements are correct and then select the answer choice containing those correct pairs.

Let me analyze each statement systematically:

Evaluating Each Statement

Statement I: Interphase nucleus — synthesis phase — metabolically active

1. The interphase is the period between cell divisions when the nucleus is not undergoing mitosis
2. During interphase, the S phase (synthesis phase) occurs, where DNA replication takes place
3. The nucleus during interphase is indeed metabolically active, with active transcription, DNA replication, and various nuclear processes occurring

This statement is CORRECT ✓

Statement II: Nucleosome — two coils — Histone

1. A nucleosome is the basic structural unit of chromatin
2. It consists of DNA wrapped around a histone octamer (8 histone proteins: 2 copies each of H2A, H2B, H3, and H4)
3. The DNA makes approximately 1.65-1.75 turns (often described as about two coils) around the histone core
4. Histones are indeed the protein component of nucleosomes

This statement is CORRECT ✓

Statement III: Contractile vacuole — Excretion — single membrane

1. Contractile vacuoles are found in freshwater protists and help regulate water balance (osmoregulation)
2. While they do expel excess water and some waste products, their primary function is osmoregulation, not excretion
3. They are indeed bounded by a single membrane

This statement is PARTIALLY CORRECT but MISLEADING — the primary function attribution is questionable ✗

Statement IV: Lysosomes — cis-trans faces — Autolysis …