Most Commonly Asked Diagrams in Life Processes

The life processes chapter has more diagrams than any other chapter in Class 10 Biology, and diagram questions are where students who know the content still lose marks. The reason is rarely the knowledge. It is a missing label, a wrongly drawn chamber, or a sketch so crowded that the examiner cannot read it.

This guide lists the diagrams that come up again and again, what each must show, the labels to include, and the slip to avoid. Use it with a pencil in your hand.

Seven Diagrams, One Method

The same five steps work for every biology diagram.

1. Draw the outline first, big enough to label. Half a page is usually right.
2. Add the major parts in their correct positions before any detail.
3. Add the details such as valves, folds or tubes.
4. Label with ruled lines that end on the part, do not cross each other, and sit in a tidy column.
5. Write a title under the diagram.

If you want the same discipline for another subject, the habits are the same as in labelling the human eye diagram for full marks.

The Human Alimentary Canal

Draw it as one continuous tube with two glands attached, following the path of the food.

Mouth → Oesophagus → Stomach → Small intestine → Large intestine → Rectum → Anus

Labels include: mouth (buccal cavity), salivary glands, oesophagus, stomach, liver, gall bladder, pancreas, small intestine, large intestine, rectum, anus.

Slip to avoid: drawing the liver and pancreas as part of the tube. They are glands that send their juices into the small intestine through ducts.

The Human Respiratory System

Labels include: nasal passage, pharynx, larynx, trachea (with its rings of cartilage), bronchi, bronchioles, lungs, alveoli, ribs and diaphragm.

Slip to avoid: forgetting the cartilage rings on the trachea, which keep the airway open, and drawing the lungs as solid blobs with no branching airways.

The Human Heart

Draw a four-chambered heart, as seen from the front, and then add the main blood vessels.

Body  →  Right atrium  →  Right ventricle  →  Lungs

Body  ←  Left ventricle  ←  Left atrium     ←  Lungs

Labels to include: right atrium, right ventricle, left atrium, left ventricle, vena cava, pulmonary artery, pulmonary vein, aorta, and the valves between atria and ventricles.

Slips to avoid: swapping the sides (the right side of the heart appears on the left of your drawing, because you draw it as it faces you), and drawing both ventricle walls the same thickness. The wall of the left ventricle is thicker, because it pumps blood to the whole body. For a step-by-step guide, see how the human heart pumps blood.

The Nephron and the Excretory System

Two diagrams are usually asked. The first is the whole system: kidneys, ureters, urinary bladder and urethra, with the renal artery and renal vein. The second is a single nephron.

Nephron labels to include: glomerulus, Bowman’s capsule, renal tubule, collecting duct, and the blood vessels around the tubule.

Slip to avoid: drawing the glomerulus outside the capsule. It is a knot of capillaries sitting inside it. There is a dedicated guide in the excretory system diagram labelling guide.

Smaller Diagrams That Still Score

A Labelling Checklist

• Is the diagram big enough to label without crowding?
• Does every label line end exactly on the part?
• Are all the parts listed in the question included?
• Are the sides, the chambers and the directions of flow correct?
• Is there a title?

Read the Command Word

The first word of a diagram question tells you how much to do, and each one asks for something slightly different.

Misreading this is a quiet way to lose marks. A student who only draws when the question says “draw and label” has done half the work.

Flow Charts Worth Knowing

Some questions ask for a pathway, not a picture. These four appear most often, and each is easy to write once you have seen it.

Passage of food in a human

Mouth → Oesophagus → Stomach → Small intestine → Large intestine → Anus

Transport of water in a plant

Root hair → Root cortex → Xylem → Stem → Leaf → Stomata (water vapour leaves)

Transport of food in a plant

Leaf (made by photosynthesis) → Phloem → Stem, roots, fruits and growing parts

Urine formation

Blood → Glomerulus (filtration) → Bowman’s capsule → Renal tubule (selective reabsorption) → Collecting duct → Ureter → Bladder → Urethra

Write the name of the process in brackets where it happens, as shown. That small addition often earns a mark by itself.

The Respiration Pathway as a Diagram

The two routes of respiration are another standard figure, and you can draw them as a branching chart.

Glucose (in the cytoplasm)

   ↓

Pyruvate

   ├─ with oxygen    → Carbon dioxide + Water + Energy (in the mitochondria)

   ├─ without oxygen (yeast)  → Ethanol + Carbon dioxide + Energy

   └─ without oxygen (muscle) → Lactic acid + Energy

Writing the place next to each step shows the examiner that you understand where each stage happens, not just what the products are.

Drawing Under Time Pressure

In the exam hall, you do not have time for a perfect picture, so decide in advance what “good enough” is.

• Practise a two-minute version of every diagram, with the correct shape, the right proportions and all the labels, rather than a ten-minute version with shading.
• Draw the labels column first, then the lines. Keeping the labels in a neat column on one side stops the lines from crossing.
• Use the same layout every time. If you always draw the heart with the vessels coming out of the top, your hand will remember where each label goes.

Why Diagrams Are Worth the Effort

A labelled diagram is the most compact way to show that you understand how a body part is built. A well-drawn heart, for example, shows the four chambers, the valves and the flow of blood in one picture, which would take a page of writing. If you practise the diagrams regularly, you will find that the rest of the chapter becomes easier too, because the diagrams force you to learn where each part sits and how it connects to the next.

Diagrams in Your Textbooks

These diagrams belong to Life Processes, which is Chapter 5 in the CBSE Class 10 Science textbook for 2026-27 and Chapter 6 in the Karnataka SSLC textbook, according to published listings. For the whole chapter at a glance, see life processes in one comparison table, and for practice questions, try the important questions on life processes. Confirm the current portions with your own board.

Frequently Asked Questions

Q1. Which diagrams are most commonly asked in the life processes chapter?

The human alimentary canal, the human respiratory system, the human heart, the excretory system and the nephron are asked most often, along with smaller diagrams such as stomata, Amoeba, and villi.

Q2. Why is the right side of the heart drawn on the left of the diagram?

Because the heart is drawn as it faces the viewer, as in a mirror. The right side of the person’s heart therefore appears on the left side of the page.

Q3. How can I make my labelled diagrams neater?

Draw large, use a pencil first, label with ruled lines that end on the part and do not cross, keep the labels in a column, and add a title.

Q4. Which parts of the alimentary canal are glands and not part of the tube?

The salivary glands, liver and pancreas are glands. They pass their secretions into the canal through ducts, but the food itself does not pass through them.

Q5. Why does the wall of the left ventricle appear thicker?

The left ventricle pumps blood to the whole body, which needs more pressure than pumping blood to the nearby lungs, so its muscular wall is thicker.

Draw Less, Label More

A good biology diagram is not a good painting. It is a clear, correct map with every part named. Practise each of these diagrams until you can draw them in about two minutes, and the section stops being a worry and starts being a reliable source of marks.