Biology 11 past paper 2025

In tRNA molecule, the main function of **middle loop** is to:

MCQ1 marksannual

How does the **Golgi complex** play a role in cell secretion and cell division?

Part B3 marksannual

Explain the steps of life cycle of Human Immunodeficiency Virus (HIV). Also draw its life cycle.

Part C7 marksannual

**Prostaglandins** are derivatives of:

MCQ1 marksannual

Compare the characteristics of **Cofactors** of enzymes with one example of each.

Part B3 marksannual

Explain different stages of xerarch succession on bare rock starting from lichens to flowering plants.

Part C7 marksannual

Write any three main features of **Bryophytes**.

Part B3 marksannual

Explain **translation process** starting from initiation complex till termination. Also draw diagram of initiation complex and elongation steps.

Part C7 marksannual

Enlist any three physical methods used to control bacteria with their mechanisms.

Part B3 marksannual

How electrons move through **electron transport chain** till they reach final acceptor? Explain. Draw diagram of electron transport chain.

Part C7 marksannual

Which enzymes break specific **covalent bonds** without hydrolysis?

MCQ1 marksannual

Justify the statement "Water is a universal solvent".

Part B3 marksannual

Describe the pathways involved in moving signals from outside to inside the cell with their diagrams.

Part C6 marksannual

**Viroids** cause:

MCQ1 marksannual

**Endospore formation** is a mechanism in bacteria to survive under unfavorable conditions. Justify.

Part B3 marksannual

Elaborate the structures and roles of **steroids** and **prostaglandins** as important group of lipids.

Part C6 marksannual

The type of flagella arrangement shown in the bacteria is: [image/diagram reference needed]

MCQ1 marksannual

List the **Accessory glands** associated with male reproductive system with their respective locations.

Part B3 marksannual

Explain the mechanism of photoperiodism.

Part C6 marksannual

Genetic material moves from donor to recipient bacterium in:

MCQ1 marksannual

What is **incomplete dominance**? Explain with a suitable example.

Part B3 marksannual

Write three distinguishing characteristics and one example of each of the phylum **Cnidaria**, **Arthropoda** and **Mollusca**.

Part C6 marksannual

Mutualistic fungi which grow between root cells of plants and do not penetrate cells is:

MCQ1 marksannual

Why and how does cyclic photophosphorylation occur in light reactions?

Part B3 marksannual

Growth movements shown by climbing plants with a supporting structure is:

MCQ1 marksannual

Write steps of **lytic cycle** in bacteriophage.

Part B3 marksannual

What is **mycorrhiza**? Differentiate between its types.

Part B3 marksannual

Radial symmetry and water vascular system are found in phylum:

MCQ1 marksannual

What is **point mutation**? How does it cause sickle cell anaemia?

Part B3 marksannual

Uterine lining in female starts breaking due to less concentration of:

MCQ1 marksannual

Compare **apoplast** and **symplast** pathways involved in uptake of water by roots in plants.

Part B3 marksannual

A forest was completely destroyed by fire. After about hundred years, a new forest evolved. The type of **succession** shown is:

MCQ1 marksannual

**Molecular biology** provides evidence of evolution. Justify the statement with reference to any three examples.

Part B3 marksannual

Write about **de-nitrification** and **assimilation** processes in nitrogen cycle.

Part B3 marksannual

In TS of a dicot stem, which substances are expected to pass through labelled parts **P** and **Q** respectively?

MCQ1 marksannual

Write about the structure and functions of **ovary** and **oviduct** in female reproductive system.

Part B3 marksannual

The structures which help bacteria to survive under unfavorable conditions include:

MCQ1 marksannual

What is **Y-linked inheritance**? How are these traits transmitted? Also give two examples.

Part B3 marksannual

Name and briefly explain **Growth Phases** of bacteria. (Any three)

Part B3 marksannual

Complete the table with reference to enzymes: - **a.** Break large molecules with water - **b.** Lyases - **c.** Cytochrome oxidase [Table structure not provided in stem]

Part B3 marksannual

Coat color in Labrador retriever shows **epistasis**. If a black ($BbEe$) and a chocolate ($bbEe$) Labrador retrievers are crossed: a. Show genotypes and phenotypes of offspring(s)…

Part B3 marksannual

Illustrate the conversion of pyruvic acid to acetyl CoA as link reaction between glycolysis and Krebs cycle.

Part B3 marksannual

Write difference in flower, stem and seed of **dicots** and **monocots**.

Part B3 marksannual

Name any three enzymes with their functions involved in DNA replication.

Part B3 marksannual

Elaborate the **endosymbiont theory** regarding evolution of chloroplast and mitochondria.

Part B3 marksannual

How is **maltose** different from **sucrose** in glycosidic linkage, monosaccharide units and specific role?

Part B3 marksannual

What are the limitations of Lamarckism?

Part B3 marksannual

Write characteristics of **angiosperms** with reference to vascular tissues and alternation of generation.

Part B3 marksannual