Class 7 · English Version · General science
2026 Class 7 Science · English Version · Chapter 1 · Chapter companion part
Compare microbes using cells, nuclei, shape and evidence rather than treating every small organism as the same.
Class 7 English Version: part A of the companion for chapter 1, Lower Organisms. Eight teaching sections, 30 written tasks and a notebook challenge. Selected companion coverage, not complete textbook coverage; practical and independent review remain.
Open this topic in Skills Lab →
Microorganisms are organisms too small to study clearly with unaided eyes. Some fungi and algae are large enough to see. The chapter title Lower Organisms is a school grouping, not a claim that small life is unimportant or less successful. Microbiology also studies viruses, which are acellular: they are not made of cells.
The source diagram uses Akaryota for acellular agents, Prokaryota for cells without a membrane-bound nucleus, and Eukaryota for cells with such a nucleus. These are the book’s comparison labels, not three universally accepted modern kingdoms. Bacteria are prokaryotic; Amoeba, fungi and algae in these examples are eukaryotic. A small organism is not automatically prokaryotic.
A virus carries genetic material, DNA or RNA, in a protein coat called a capsid; some viruses also have an envelope. A particle is not a tiny complete cell: it has no ribosomes or independent cellular metabolism. Viruses depend on suitable living host cells to make more virus particles. A bacteriophage is a virus that infects bacteria; its head-and-tail drawing is not the shape of every virus.
A bacterium is a single cell with a membrane, cytoplasm, ribosomes and genetic material, but no membrane-bound nucleus. Many have a cell wall. Some bacteria can photosynthesise, so the source description non-green is not a rule for all bacteria. Bacteria can reproduce by binary fission, in which one cell divides into two; viruses cannot do this on their own.
Coccus describes a roughly spherical bacterium; bacillus describes a rod; a vibrio is curved like a comma; a spirillum is spiral-shaped. The book uses Comma as the third shape label. A shape is a descriptive clue, not enough to identify a species or diagnose a disease. A coloured sketch is a model, not an observation through a microscope.
Amoeba has a cell membrane, cytoplasm and a nucleus. Temporary extensions called pseudopodia help it move and surround food. Food vacuoles hold engulfed material; a contractile vacuole helps remove excess water in a freshwater example. These are different jobs. Its changing outline does not mean it lacks a cell boundary or organised internal structures.
A microscope magnifies an image; useful detail also depends on its resolving ability, meaning whether close features can be distinguished separately. A routine school light microscope does not show every detail of a virus or bacterium. Use supplied images, their labels and scale bars. State when information is not visible instead of filling a drawing with imagined observations.
Compare an acellular virus, a bacterial cell and Amoeba in columns: cell present, membrane-bound nucleus, and how more individuals or particles are produced. A virus needs a host cell; a bacterium can divide; an Amoeba is a nucleated cell. Neither small size nor harmfulness alone separates these groups. Leave disease identification to qualified professionals, not a shape-matching game.
A supplied particle has genetic material inside a protein coat and uses a host cell: it fits the virus model. A second example has cytoplasm, ribosomes and DNA but no nuclear membrane: it fits a bacterial cell. These descriptions do not identify a disease.
Printed page 2 describes microorganisms as primitive organisms and then includes nucleated microbes. Use its later structural comparison: Amoeba and fungi have nuclei; bacteria do not have a membrane-bound nucleus. Microscopic does not mean primitive.
A supplied yeast cell has a nucleus and ribosomes. It belongs with eukaryotic cells even though it is small; the presence of a nucleus is more useful than size.
Match each letter to its structure and function. These original study diagrams are simplified models, not microscope observations.
The book uses Akaryota, Prokaryota and Eukaryota as comparison groups. This is not a universal modern three-kingdom classification.
Original schematic, not to scale or a microscope image. The source labels head, DNA, collar, tail and tail fibre; baseplate and sheath/tube distinction add explanation.
Original schematic at a common display size, not actual cell-size measurements. Source figure 1.4 does not clearly match its comma-shaped description; this plate shows a curved vibrio. A thin flagellum is a separate structure, not the bacterial cell body. Colours are study labels.
Original schematic, not to scale. Outer/inner cytoplasm names describe regions and physical state, not extra membranes. All nine lettered details have a text guide.
Show your working on paper and enter your answer here. If it does not match, compare the model and try again.
acellular
Acellular distinguishes a virus particle from a bacterial cell.
capsid
Some viruses also have an envelope; the capsid is the protein coat.
bacteriophage
A bacteriophage infects a bacterium.
prokaryotic
Bacteria have genetic material without a membrane-bound nucleus.
eukaryotic
Amoeba has a membrane-bound nucleus.
coccus
Coccus names the spherical shape, not a disease.
bacillus
Bacillus is the singular shape word.
vibrio
The chapter labels this shape Comma.
pseudopodia
Pseudopodia are extensions of the cell.
binary fission
This cell-division process is different from viral replication in a host.
Write in your own words. A guardian or teacher should review this response.
Amoeba and yeast are microscopic eukaryotes with nuclei. A bacterium is prokaryotic. Size alone does not establish cell organisation.
Give a counterexample and the relevant structural distinction.
Write in your own words. A guardian or teacher should review this response.
A bacterium is a cell with ribosomes and can divide under suitable conditions. A virus particle is acellular and uses a living host cell to produce more particles.
Do not claim that a virus divides like a bacterium.
Write in your own words. A guardian or teacher should review this response.
Use it to compare acellular agents, non-nucleated cells and nucleated cells. Modern classification uses further evidence and does not recognise these three labels as one universal kingdom scheme.
Separate the source’s classroom model from a universal classification claim.
Write in your own words. A guardian or teacher should review this response.
Keep the genetic material but remove the membrane-bound nucleus label; bacteria do not have that nuclear compartment.
Lacking a nucleus does not mean lacking DNA.
Write in your own words. A guardian or teacher should review this response.
Use spirillum for a spiral shape; coccus describes a roughly spherical cell. Shape supports a descriptive label, not a species diagnosis.
Name the observed shape and avoid a disease conclusion.
Write in your own words. A guardian or teacher should review this response.
An extension of cytoplasm surrounds food and encloses it in a food vacuole, where digestion can occur.
Connect the extension, enclosure and vacuole rather than calling it a permanent leg.
Write in your own words. A guardian or teacher should review this response.
A food vacuole contains engulfed food; a contractile vacuole collects and expels excess water.
Compare functions, not merely the circular shapes in a diagram.
Write in your own words. A guardian or teacher should review this response.
It may be a schematic based on other techniques. A routine light microscope has limited resolution; check the source, scale and method before calling details observed.
Distinguish a model from an actual observation.
Write in your own words. A guardian or teacher should review this response.
Some bacteria, including cyanobacteria, photosynthesise. Identify bacteria using their cellular organisation rather than a rule that all are non-green.
Do not turn the book’s simplified description into a universal claim.
Write in your own words. A guardian or teacher should review this response.
Use cell present, membrane-bound nucleus, and reproduction or replication. Harmless and harmful examples occur among microbes, so harmfulness does not identify cell organisation.
Use structural evidence and make no diagnosis.
B
B points inside the protein head.
E
E marks attachment fibres, not a nucleus.
D
D has the spiral outline.
F
F identifies the excess-water-removal structure.
D
D marks the genetic-information compartment.
Write in your own words. A guardian or teacher should review this response.
A is the protein capsid, B the DNA inside it, and E the tail fibres used in host attachment. None is a cell nucleus.
Match all three markers and distinguish protection, information and attachment.
Write in your own words. A guardian or teacher should review this response.
B and C are outer gel-like and inner more fluid cytoplasmic regions; A is the surrounding cell membrane. The regions are not separate cell walls.
Include the source’s plasma gel/plasma sol names without inventing extra boundaries.
Write in your own words. A guardian or teacher should review this response.
E contains food, F is the contractile vacuole for excess-water removal, and H is a small water-filled space whose function is not established just by its circular appearance.
Use the legend rather than assuming every circle has the same function.
Write in your own words. A guardian or teacher should review this response.
I marks the rear uroid region, while D marks the nucleus. A trailing region is not another genetic-information compartment.
Read both marker positions and the structure/function guide.
Write in your own words. A guardian or teacher should review this response.
They are schematic display sizes, not measured images. No real-size comparison follows without a valid scale.
Explain the lack of a measurement scale rather than inventing a cell diameter.
Draw three labelled paper models: virus particle, bacterial cell and Amoeba. Compare their organisation and state one limit of each drawing.
Keep your work on paper or in a local file. This page does not upload it or automatically grade the project.
This original Kidemy practice follows the topic order of 2026 Class 7 Science · English Version, chapter 1, printed pages 1–11. It does not replace the complete chapter or its practical teaching.
Official book catalogue and source →
Teacher-led lessons, schedules and prices for this outline are upcoming. You can use any starter practice above now without booking.
Solo practice works without an account. Sign in to save a practice record to your learner profile.
Exact lesson links and related activities are labelled separately. Return-to-course links retain your selected learning path.