Unit Model Paper — Biology HSSC–I — Unit 1 Cell and Sub-Cellular Organelles

Unit Model Paper — Biology HSSC–I — Unit 1 Cell and Sub-Cellular Organelles — Athens Academy Islamabad

BIOLOGY HSSC–I

UNIT 1 — CELL AND SUB-CELLULAR ORGANELLES · FBISE · EXAM 2027

Questions drawn from the Athens Academy Unit 1 study notes

Time allowed: 2:35 Hours

Total Marks Sections B and C: 68

Every question is from Unit 1 only. Where an OR choice is offered, both alternatives are also from Unit 1.

SECTION – A (Marks 17)

Q. 1 Multiple choice questions. Attempt all.

(17 x 1 = 17)

Section A is not printed on this paper

Section A is compulsory and is collected separately within the first 25 minutes. Practise it on the Athens Academy Islamabad portal, where it is marked instantly:

Unit 1 MCQ bank · Unit 1 Online Quiz · Unit 1 Flashcards — aim for 15/17 three times in a row before attempting this paper.

SECTION – B (Marks 42)

Q. 2 Answer the following questions briefly.

(14 x 3 = 42)

(i)

★ Elaborate the role of peroxisomes in plant and animal cells.BIO-11-1.8.7

2+1

Relate the variety of proteins of the plasma membrane with their respective roles. (Any three)BIO-11-1.5.2

(ii)

★ Illustrate the three layers of the plant cell wall, naming the composition and function of each.BIO-11-1.5.1

Illustrate the fluid mosaic model of the plasma membrane with labelling.BIO-11-1.5.2

(iii)

★ Justify the significance of the Svedberg unit by explaining why a 60S and a 40S subunit form an 80S ribosome.BIO-11-1.4.2

Outline the process of receptor-mediated endocytosis in a flow chart.BIO-11-1.11.1

(iv)

★ How do channel proteins and carrier proteins work in facilitated diffusion? Also give one distinguishing feature of each.BIO-11-1.7.2

How does autophagy occur in a cell? How does it help the cell to withstand unfavourable conditions?BIO-11-1.8.6

2+1

(v)

★ Describe the steps of the cell cycle, stating what happens in G₁, S and G₂.BIO-11-1.12.1

Explain the role of lysosomes in human cells, with three processes they carry out.BIO-11-1.8.6

(vi)

★ A cell is placed in a solution and begins to swell.

How does osmosis cause this?
Why is osmosis called a passive process?

BIO-11-1.7.4

2+1

A prokaryotic cell is shown in a diagram.

Name the structures that store its DNA and synthesise its proteins.
Write the chemical composition of its cell wall.
Name the process by which it divides.

BIO-11-1.9.1

1x3

(vii)

★ Stem cells are classified by potency. Name any three levels of potency with their specific abilities.BIO-11-1.10.3

Write about the structural adaptations of the mitochondrion regarding its membranes, its matrix and its own genetic material.BIO-11-1.8.9

(viii)

★ Briefly explain the flow of a secretory protein through the cell as regulated by the endomembrane system.BIO-11-1.8.4

Write down the steps of phagocytosis carried out by a white blood cell.BIO-11-1.11.1

(ix)

★

How does the concentration of unsaturated fatty acids affect membrane fluidity?
Compare the role of cholesterol in the membrane at high and at low temperature.

BIO-11-1.5.2

2+1

Name any three types of plastid with one salient feature and one example of each.BIO-11-1.8.10

(x)

★ In the sodium–potassium pump, how do ATP and the carrier protein help in the process?BIO-11-1.7.5

2+1

Name and explain two exceptions to cell theory.BIO-11-1.2.4

(xi)

★ Complete the table:

	Description	Organelle
a	Double membrane, has its own DNA and 70S ribosomes
b		Ribosome
c	Single membrane, contains hydrolytic enzymes

BIO-11-1.8.14

The cell cycle is shown in the diagram:

Name the phases marked P and Q.
Which process is shown at X?
Which phase is the shortest part of the cycle?

BIO-11-1.12.1

(xii)

★ Write the working principle of the electron microscope. Also write its resolving power and one advantage over the light microscope.BIO-11-1.3.3

Write down the mechanism of signal transduction in protein signalling.BIO-11-1.6.2

(xiii)

★ What are glyoxysomes? Enlist any two features and give one example of where they occur.BIO-11-1.8.7

How is the cell wall involved in protecting the plant cell? Enlist any three of its functions.BIO-11-1.5.1

(xiv)

★ Name two advantages and one disadvantage of iPSCs, with one major effect of each on patient treatment.BIO-11-1.10.4

Write the mechanism of crossing over in meiosis with reference to the chiasma.BIO-11-1.12.3

SECTION – C (Marks 26)

Attempt the following questions.

(26)

Q.3

★ The cell theory took two centuries to complete. How did cell theory evolve? Name the contribution of each scientist and state the three tenets.BIO-11-1.2.1 · 1.2.2

How are influx and efflux of ions involved in active transport across the plasma membrane? Explain primary and secondary active transport in detail.BIO-11-1.7.5

3+3

Q.4

★ Explain intracellular digestion in the cell. Describe the formation of the lysosome and the processes of autophagy, autolysis and phagocytosis.BIO-11-1.8.6

2+5

Describe the structure and functions of the Golgi complex. Also draw its diagram.BIO-11-1.8.4

2+4
+1

Q.5

★ Give a detailed account of the general characteristics of the chloroplast — its envelope, stroma, thylakoids and grana — and state where the light and dark reactions occur.BIO-11-1.8.10

Explain protein signalling and steroid signalling as two important pathways of cell communication. Describe their roles in living organisms.BIO-11-1.6.3

3+3

Q.6

★ Cells divide to maintain life. Explain mitosis, naming all five stages with what happens in each. Also draw diagrams showing metaphase and anaphase.BIO-11-1.12.2

5+2

What is meiosis? Explain its different stages in the first meiotic division. Also draw a neat sketch of crossing over.BIO-11-1.12.3

1+5
+1

——·(B)·——

BOARD MARKING PATTERN

Section	Structure	Attempt	Marks
A	17 MCQs × 1 mark	All — compulsory, collected in first 25 min	17
B	Q.2, 14 parts × 3 marks, each with an OR choice	All 14 parts, one option each	42
C	Q.3–Q.6, 4 questions, each with an OR choice	All 4 questions, one option each	26
Total	Theory paper	Time: 25 min + 2:35 hours	85

Cognitive split across the paper is approximately 30% knowledge, 50% understanding and 20% application. Sub-parts in Section C carry 4 or more marks each, and questions asking for a labelled diagram award 1 mark for the drawing.

Practical assessment (15 marks, through PBA) is recorded separately and does not form part of this theory paper.

Exam tip — how to use the OR choice

The board gives you an OR on every part, and this is where marks are won and lost. Do not answer in printed order. Spend the first three minutes reading the whole paper and pencil a tick beside the option you can answer best in each pair. Then answer your ticked options first.

Two warnings. First, if a question says “also draw”, the diagram carries its own mark — a perfect description with no drawing still loses it. Second, once you commit to an option, cross out the other cleanly; if you attempt both, the examiner marks the first one only.

Athens Academy Islamabad

Biology · Grade 11 (HSSC–I) · Unit 1 — Cell and Sub-Cellular Organelles · FBISE · Exam 2027

Unit model paper compiled for student practice. Built on the FBISE paper pattern — not produced or endorsed by FBISE.

📃 Chapter 1 · Cells and Sub-Cellular Organelles — Chapter Model Paper

Model Paper: Cells and Sub-Cellular Organelles