Plants

Plant organs: leaf, stem, root

An organ is several tissues working as one part. In a plant the leaf, stem and root are the organs you must be able to read.

CAPS

Grade 10 · Life Sciences · Plants

Life Sciences is two papers. Use the strand to know which one.

  • Where it is examined

    Grade 10 is the chemistry of life, cells, tissues, organs, support and transport, and the biosphere, biodiversity and the history of life.

  • How to write it

    Name the structure, then say what it does. A labelled diagram only scores if the labels are the biological names. “It helps the body” is not a function.

  • How a marker reads it

    A common mix-up is to say roots photosynthesise, or that stomata are for taking up soil water.

A 2-mark “explain” wants two facts, or one fact and its reason. Extra sentences that contradict the first one can cancel a mark.

light

Diagram

Worked theory

Worked theory. A tomato plant on a windowsill. The leaf faces the light so palisade cells can catch it. Stomata on the underside let carbon dioxide in. If those stomata stayed shut all day, photosynthesis would slow because carbon dioxide could not enter. The stem’s bundles move water up from the root and sugars down from the leaf. The root hairs, not the green leaf, are what meet the wet soil. Paint the leaf and you have not explained it. The explanation is what each tissue is for.

More worked examples

  • Bean on wet cotton wool

    A bean left on wet cotton wool splits and a white root grows down, with a fuzzy band of root hairs a few millimetres behind the tip. Those hairs are the organ’s absorbing surface. The shoot that follows grows up and opens leaves. Cover the leaves with petroleum jelly and the plant yellows, because the leaf can no longer take in carbon dioxide. The root hairs in the wet wool are still fine. The failed organ is the leaf.

  • One leaf in a cupboard

    A bean leaf left on the plant in the light stays green and makes starch. A leaf from the same plant, sealed in a cupboard for a week, turns pale. The root and the stem were still in the light on the windowsill plant. The failed part was the leaf that could not get light, so its chloroplasts stopped paying their way. Covering the pot does not test the leaf. Covering the leaf does.

In ordinary words

The leaf is built to photosynthesise: a waxy cuticle, epidermis, palisade cells packed with chloroplasts, spongy cells with air spaces, and stomata that open for carbon dioxide and close to save water. The stem holds the plant up and carries xylem and phloem in vascular bundles. The root anchors the plant, grows hairs for a large surface, and takes up water and mineral salts. A flower is a reproductive organ, not a leaf.

In South Africa

A bean plant in a cooldrink bottle is enough to see leaf, stem and root as three organs.

Part 1 / 4

What it is

An organ is several tissues working as one part. In a plant the leaf, stem and root are the organs you must be able to read.

Diagram
Diagram
Diagram

More worked examples

Board walkthroughs on this topic. Open one, copy the working, then try the next.

Example 1 / 20

Give three ways a leaf is adapted for photosynthesis.

How we got there

Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

Explain in another language · 11

1. What is the question asking?

Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: Give three ways a leaf is adapted for photosynthesis.

In other words — as if you have never seen this before

If you have never seen this before: Think light, CO₂ and water. We will name a method in words, write the formula with no numbers, then substitute one line at a time.

2. What do we already know?

Leaf structure.

3. Which method — and why this one?

Think light, CO₂ and water.

4. Step-by-step working

  1. 01 / 05

    Identify the given

    Broad, thin lamina → large surface area for light; short diffusion distance.

    Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.

  2. 02 / 05

    Identify the given

    Palisade cells with many chloroplasts near the upper surface; stomata for CO₂ entry; veins bring water.

    Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.

  3. 03 / 05

    Step G — Sense-check the size

    Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

    Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

  4. 04 / 05

    Step F — Box the answer with its unit

    Large flat surface, many chloroplasts in palisade layer, stomata and veins.

    Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

  5. 05 / 05

    Step H — What the marker is looking for

    On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

    Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

5. The answer

Large flat surface, many chloroplasts in palisade layer, stomata and veins.

Copy onto your answer sheet — in this order

Answer: Large flat surface, many chloroplasts in palisade layer, stomata and veins.

6. Check it like a marker

Each adaptation must be linked to a need.

7. A trap first-timers fall into

First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”

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