Cell structure (animal cells) — KCSE Biology

KCSE Biology · 97 practice questions · 3 syllabus objectives · 3 revision lessons

35 easy35 medium27 hard

Last updated · Aligned to the KNEC KCSE syllabus

What You'll Learn

Key learning outcomes for this topic, aligned to the KNEC KCSE syllabus.

Draw and label an animal cell as seen under an electron microscope

Distinguish between plant and animal cells

Cell structure (animal cells)

Revision Notes

Concise lesson notes for Cell structure (animal cells), written to the KCSE Biology marking standard. Read the first lesson free below.

Drawing and Labeling an Animal Cell

To draw and label an animal cell as seen under an electron microscope, start by outlining the cell's shape, which is generally irregular and flexible. Key structures to include:

  • Cell membrane: A thin, flexible barrier surrounding the cell.
  • Nucleus: The control center, often spherical and contains genetic material.
  • Cytoplasm: The jelly-like substance filling the cell.
  • Mitochondria: Bean-shaped organelles responsible for energy production.
  • Endoplasmic reticulum (ER): A network of membranes; rough ER has ribosomes, while smooth ER does not.
  • Ribosomes: Tiny structures for protein synthesis, often found on the rough ER.
  • Golgi apparatus: Stacked membranes involved in modifying and packaging proteins.
  • Lysosomes: Small, round organelles containing enzymes for digestion.

When labeling, ensure the names are clear and placed near the respective structures. Use a ruler for neatness and clarity. Remember to use a pencil for drawing and a pen for labeling to enhance visibility.

Key points to remember

  • Draw an irregular shape for the animal cell.
  • Label the cell membrane, nucleus, and cytoplasm clearly.
  • Include organelles like mitochondria and Golgi apparatus.
  • Use neat lines and clear handwriting for labels.
  • Ensure labels are positioned close to the structures.

Worked example

Draw an animal cell and label the nucleus, mitochondria, and ribosomes.

  • The cell is oval-shaped with a clear cell membrane.
  • The nucleus is large and centrally located.
  • Mitochondria are shown as oval structures with inner folds.
  • Ribosomes are depicted as small dots on the rough ER.

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More lessons in this topic

Lesson 2: Differences Between Plant and Animal Cells

Objective: Distinguish between plant and animal cells

Animal cells and plant cells have distinct structures that serve different functions. Here are the key differences:

  • Cell wall: Plant cells have a rigid cell wall made of cellulose, providing structure and support. Animal cells lack a cell wall and have only a flexible cell membrane.
  • Chloroplasts: Plant cells contain chloroplasts for photosynthesis, allowing them to convert sunlight into energy. Animal cells do not have chloroplasts since they obtain energy by consuming food.
  • Vacuoles: Plant cells typically have a large central vacuole for storage and maintaining turgor pressure. In contrast, animal cells have smaller vacuoles, if present, that serve various storage functions.
  • Shape: Plant cells are usually rectangular or cube-shaped due to the cell wall, while animal cells are generally round or irregular in shape.

Understanding these differences is crucial for recognizing how each cell type contributes to the overall function of an organism.

  • Plant cells have a rigid cell wall; animal cells do not.
  • Chloroplasts are present in plant cells for photosynthesis.
  • Plant cells have a large central vacuole; animal cells have smaller vacuoles.
  • Plant cells are typically rectangular; animal cells are usually round.

Question: List two differences between plant and animal cells.

  • Plant cells have a cell wall; animal cells have only a cell membrane.
  • Plant cells contain chloroplasts; animal cells do not.
Lesson 3: Understanding Animal Cell Structure

Objective: Cell structure (animal cells)

Animal cells are complex structures that perform various functions necessary for life. They are eukaryotic cells, meaning they have a defined nucleus and membrane-bound organelles. Key components of an animal cell include:

  • Cell membrane: A semi-permeable barrier that controls the entry and exit of substances.
  • Nucleus: Contains genetic material (DNA) and regulates cell activities.
  • Cytoplasm: Jelly-like fluid where organelles are suspended and metabolic reactions occur.
  • Mitochondria: Known as the powerhouse of the cell, they generate energy (ATP) through respiration.
  • Ribosomes: Sites of protein synthesis, found either floating in the cytoplasm or attached to the endoplasmic reticulum.
  • Endoplasmic reticulum (ER): Rough ER has ribosomes and synthesizes proteins, while smooth ER synthesizes lipids and detoxifies.
  • Golgi apparatus: Modifies, sorts, and packages proteins and lipids for secretion or use within the cell.

Understanding these structures and their functions is crucial for grasping how cells operate and interact within living organisms.

  • Animal cells are eukaryotic with a defined nucleus.
  • Key organelles include mitochondria, ribosomes, and Golgi apparatus.
  • Cell membrane regulates substance movement in and out.
  • Cytoplasm is where metabolic reactions occur.
  • Each organelle has a specific function contributing to cell health.

Describe two functions of the mitochondria in animal cells.

  • Mitochondria produce ATP through aerobic respiration, providing energy for cellular processes.
  • They also regulate metabolic activities and apoptosis (programmed cell death).

Sample Questions

Read 3 questions and answers free. Sign up to access all 97 questions with full KNEC-style marking schemes and a personalised study plan.

1
easySHORT ANSWER4 marks

In the study of microscopic organisms, understanding the components and functions of a light microscope is essential for accurate observation and analysis. This knowledge enables students to effectively explore the intricate details of animal cell structures. (a) State the function of each of the following parts of a light microscope: (i) Eyepiece lens (1 mark) (ii) Revolving nosepiece (1 mark) (iii) Fine adjustment knob (1 mark) (b) Which part of the microscope is used to obtain a sharper outline of a specimen under high power? (1 mark)

Answer & marking scheme

Part (a_i) — 1 mark
Magnifies the image produced by the objective lens for viewing; (1 mk)
Part (a_ii) — 1 mark
Holds the objective lenses and allows rotation to change magnification; (1 mk)
Part (a_iii) — 1 mark
Brings the specimen into rough/approximate focus by raising or lowering the body tube; (1 mk)
Part (b) — 1 mark
Fine adjustment knob; (1 mk)
2
easyCalculation3 marks

In the study of cellular biology, understanding the measurements and magnification techniques is essential for accurately analyzing the intricate structures of animal cells. This knowledge is fundamental for students as they explore the microscopic world. (a) Convert 2 mm to μm (micrometres). (1 mark) (b) Convert 1500 μm (micrometres) to mm. (1 mark) (c) State the formula used to calculate the magnification of an object viewed under a light microscope. (1 mark)

Answer & marking scheme

Part (a) — 1 mark
2000 μm (micrometres); (1 mk)
Part (b) — 1 mark
5 mm; (1 mk)
Part (c) — 1 mark
Magnification = Image size ÷ Actual size; (or Magnification = Eyepiece lens × Objective lens); (1 mk)
3
easySHORT ANSWER4 marks

In the study of microscopic organisms, understanding the components and functions of a light microscope is essential for accurate observation and analysis. This knowledge enables students to effectively explore the intricate details of animal cell structures. (a) State the function of each of the following parts of a light microscope: (i) Eyepiece lens (1 mark) (ii) Condenser (1 mark) (iii) Fine adjustment knob (1 mark) (b) Which part of the microscope is used to obtain a sharper outline of a specimen under high power? (1 mark)

Answer & marking scheme

Part (a_i) — 1 mark
Produces the primary magnified image of the specimen; (1 mk)
Part (a_ii) — 1 mark
Holds the objective lenses and allows rotation to change magnification; (1 mk)
Part (a_iii) — 1 mark
Provides illumination/directs light through the specimen; (1 mk)
Part (b) — 1 mark
Fine adjustment knob; (1 mk)
4

In the study of cellular biology, understanding the measurements and magnification techniques is essential for accurately analyzing the intricate structures of animal cells. This knowledge is fundamental for students as they explore the microscopic world. (a) Convert 0.5 mm to μm (micrometres). (1 mark) (b) Convert 5000 nm (nanometres) to μm (micrometres). (1 mark) (c) State the formula used to calculate the magnification of an object viewed under a light microscope. (1 mark)

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Frequently asked questions

What does the KCSE Biology topic "Cell structure (animal cells)" cover?

Cell structure (animal cells) covers Draw and label an animal cell as seen under an electron microscope; Distinguish between plant and animal cells; Cell structure (animal cells), all aligned to the official KNEC KCSE Biology syllabus.

How many practice questions are available for Cell structure (animal cells)?

HighMarks has 97 Cell structure (animal cells) practice questions for KCSE Biology, each with a full marking scheme. The first 3 are free; sign up to access the rest, plus all KCSE mock exams and past papers.

Are these aligned with the KNEC KCSE syllabus?

Yes. Every objective on this page is taken directly from the official KNEC KCSE Biology syllabus. Practice questions match the KCSE exam format and are graded against the standard KNEC marking scheme.

How should I revise Cell structure (animal cells) for the KCSE exam?

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