Grade 12 results are out. Where to check yours

Unit notes and practice questions

Grade 9 Biology unit 1: Introduction to Biology

Everything here is for unit 1 of the Grade 9 Biology textbook: what the chapter covers, the short notes, practice questions with their answers, and the lesson video where one exists.

Get it on Google Play
4
Cards
10
Practice questions on unit 1
1–18
The textbook pages for unit 1

What unit 1 covers

  1. 1.Definition of Biology
  2. 2.Why do we study Biology?
  3. 3.The scientific method
  4. 4.Tools of a Biologist method
  5. 5.Laboratory tools
  6. 6.Field tools
  7. 7.Handling and using of light Microscope
  8. 8.Parts and function of light microscope
  9. 9.Handling and using microscope
  10. 10.General Laboratory Safety Rules

Short notes for unit 1

The cards filed under this chapter on the Grade 9 Biology page. Open one at a time.

ToolPrimary Function
AutoclaveSterilizes equipment and kills bacterial spores using steam
IncubatorMaintains optimal temperature for microbial growth
Petri dishHolds solid culture media such as agar
Slide and cover slipSupports specimen and prevents drying during viewing
Dissecting kitHolds tools required to cut and examine internal organs
TongsLifts heated crucibles, beakers, and hot glassware

When you use it

Use this reference table to match laboratory equipment with their functions.

Watch out

Do not confuse an autoclave, which sterilizes at high heat, with an incubator, which maintains growth temperature.

Drafted from Grade 9 Biology, pages 1-18, then checked twice before it went up

When you use it

Use this sequence when planning an investigation or ordering the steps of scientific inquiry: Observation, Question, Hypothesis, Experiment, Conclusion, and Communication.

Watch out

A hypothesis must be proposed before the experiment is run, and it must be testable through repeatable testing.

Drafted from Grade 9 Biology, pages 1-18, then checked twice before it went up

Mtotal=Meyepiece×MobjectiveM_{\text{total}} = M_{\text{eyepiece}} \times M_{\text{objective}}
MtotalM_{\text{total}}
Total magnification11
MeyepieceM_{\text{eyepiece}}
Magnification of the eyepiece lens11
MobjectiveM_{\text{objective}}
Magnification of the objective lens11

When you use it

Use this formula to calculate total magnification from the given ocular and objective lens powers.

Watch out

Total magnification is the product of eyepiece and objective magnifications, not their sum.

Drafted from Grade 9 Biology, pages 1-18, then checked twice before it went up

When you use it

Use this rule when describing microscope focusing procedures.

Watch out

Never use the coarse adjustment knob under high power objectives. It moves the stage too far and can break the glass slide and the lens.

Drafted from Grade 9 Biology, pages 1-18, then checked twice before it went up

Practice questions on unit 1

10 multiple-choice questions written against this chapter, each with its answer and the reason. Try one before you open the answer.

Question 1

The word Biology is derived from two Greek words: bios and logos. What does the word bios mean?

  1. A.Life
  2. B.Study
  3. C.Earth
  4. D.Science
Show the answer and why

Answer: A Life

Why

The textbook states that Biology comes from two Greek words: bios meaning life, and logos meaning study.

Question 2

In the scientific method, what is a hypothesis?

  1. A.A final conclusion accepted by all scientists
  2. B.A proposed scientific explanation that is testable
  3. C.A tool used to magnify small microorganisms
  4. D.A published paper in a scientific journal
Show the answer and why

Answer: B A proposed scientific explanation that is testable

Why

A hypothesis is a proposed scientific explanation (possible answer) for a question or set of questions, and it must be testable through experimentation.

Question 3

If a student uses a compound light microscope with a 10x eyepiece lens and a 40x objective lens, what is the total magnification?

  1. A.30x
  2. B.50x
  3. C.400x
  4. D.4000x
Show the answer and why

Answer: C 400x

Why

The total magnification of a compound light microscope is calculated by multiplying the eyepiece magnification by the objective lens magnification (10 multiplied by 40 equals 400x).

Question 4

What should you immediately do if a laboratory chemical splashes onto your skin and causes a burn?

  1. A.Apply cooking oil over the burn
  2. B.Cover the burn tightly with a dry cloth
  3. C.Flood the burned area with cold tap water for several minutes
  4. D.Wait until the end of the laboratory class to report it
Show the answer and why

Answer: C Flood the burned area with cold tap water for several minutes

Why

Laboratory safety rules state that if someone is burned or exposed to a chemical, they must immediately flood the affected area with cold tap water for several minutes to minimize damage.

Question 5

Which piece of equipment is used to kill microorganisms and their resistant spores by using high temperatures and highly pressurized steam?

  1. A.Incubator
  2. B.Autoclave
  3. C.Hotplate
  4. D.Petri dish
Show the answer and why

Answer: B Autoclave

Why

An autoclave is used to sterilize biological samples and equipment by exposing them to high temperatures and highly pressurized steam, which kills both microorganisms and their spores.

Question 6

Antibiotics such as penicillin are produced by which of the following organisms?

  1. A.Mould fungi or bacteria
  2. B.Viruses
  3. C.Insects
  4. D.Green algae
Show the answer and why

Answer: A Mould fungi or bacteria

Why

The textbook states that antibiotics, such as penicillin, are produced by mould fungi or bacteria.

Question 7

What is the primary role of the diaphragm (iris) on a light microscope?

  1. A.To hold the microscope slide firmly in place
  2. B.To control the amount and size of the light beam reaching the specimen
  3. C.To connect the eyepiece tube to the objective lenses
  4. D.To move the stage quickly for rough focusing
Show the answer and why

Answer: B To control the amount and size of the light beam reaching the specimen

Why

The diaphragm is located under the stage and functions to regulate the light intensity and control the size of the beam of light that reaches the specimen.

Question 8

How does the coarse adjustment knob differ from the fine adjustment knob on a light microscope?

  1. A.Coarse adjustment brings the image into general focus roughly, while fine adjustment achieves sharpness.
  2. B.Coarse adjustment turns the light on, while fine adjustment changes the objective lenses.
  3. C.Coarse adjustment is used only with 100x lenses, while fine adjustment is used with 4x lenses.
  4. D.Coarse adjustment moves the eyepiece, while fine adjustment holds the slide.
Show the answer and why

Answer: A Coarse adjustment brings the image into general focus roughly, while fine adjustment achieves sharpness.

Why

The coarse adjustment captures the distance roughly and quickly to bring the specimen into general focus, while the fine adjustment moves the stage minimally to achieve sharpness.

Question 9

Why are electron microscopes able to view extremely small structures such as viruses that cannot be seen under a light microscope?

  1. A.They use thicker glass slides and wide cover slips.
  2. B.They use a beam of electrons and electromagnets instead of light and glass lenses.
  3. C.They use two light bulbs placed beneath the stage.
  4. D.They use single convex lenses attached to wooden handles.
Show the answer and why

Answer: B They use a beam of electrons and electromagnets instead of light and glass lenses.

Why

Electron microscopes provide much higher magnification and resolution because they use a beam of electrons and electromagnets instead of a beam of light and glass lenses.

Question 10

A laboratory technician in Addis Ababa wants to culture a large population of bacteria using only liquid broth media. Which glassware is designed specifically for this purpose?

  1. A.Petri dish
  2. B.Dissecting pan
  3. C.Flask
  4. D.Crucible
Show the answer and why

Answer: C Flask

Why

A flask has a flat bottom and a long narrow neck that allows mixing without spilling. It is essentially a large volume culture tube used only with broth media to produce large populations of microorganisms.

The app holds 12 questions on this unit, marked as you go. These are the first 10.

The textbook pages for unit 1

Unit 1 runs from page 1 to page 18 of the Ministry of Education edition.

Ministry of Education edition, English, 165 pages

Download the PDF

All Grade 9 Biology short notes

Practise this unit in the app

Temari turns this chapter into timed practice and marks it as you go, with an AI tutor to explain anything that did not land.

Start free

Temari.et is also an Android app, free on Google Play.

Get it on Google PlayAbout the Temari app
Sign inCreate your account