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Cells and Living Things - Specialized Cells

Grade 6IGCSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Specialized cells are cells that have developed specific shapes and structures to perform particular functions through a process called differentiation.

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Red Blood Cells (Erythrocytes): Adapted for carrying oxygen (O2O_2). They have a biconcave shape to increase surface area and lack a nucleus to make more room for hemoglobin (HbHb).

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Nerve Cells (Neurons): Long, thin cells that carry electrical impulses. They have branched endings (dendrites) to connect with many other cells.

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Ciliated Cells: Found in the respiratory tract; they have tiny hair-like structures called cilia that move mucus containing trapped dust and bacteria away from the lungs.

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Sperm Cells: Adapted for reproduction. They have a tail (flagellum) for swimming and many mitochondria to provide energy in the form of ATPATP.

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Root Hair Cells: Plant cells with a long 'hair' extension that increases the surface area for the absorption of water (H2OH_2O) and mineral ions.

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Palisade Mesophyll Cells: Found in leaves; they contain many chloroplasts for photosynthesis, represented by the equation 6CO2+6H2O→C6H12O6+6O26CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2.

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Levels of Organization: Specialized cells →\rightarrow Tissues →\rightarrow Organs →\rightarrow Organ Systems →\rightarrow Organism.

📐Formulae

Magnification=Measured size of imageActual size of objectMagnification = \frac{\text{Measured size of image}}{\text{Actual size of object}}

Actual Size=Image SizeMagnification\text{Actual Size} = \frac{\text{Image Size}}{\text{Magnification}}

6CO2+6H2O→lightC6H12O6+6O26CO_2 + 6H_2O \xrightarrow{\text{light}} C_6H_{12}O_6 + 6O_2

💡Examples

Problem 1:

A student views a root hair cell under a microscope. The image size of the cell is 30 mm30\text{ mm}, and the actual size is 0.15 mm0.15\text{ mm}. Calculate the magnification used.

Solution:

Magnification=30 mm0.15 mm=200×Magnification = \frac{30\text{ mm}}{0.15\text{ mm}} = 200\times

Explanation:

To find the magnification, divide the measured image size by the actual size of the cell. Ensure both measurements are in the same units (mm).

Problem 2:

Explain why a Red Blood Cell does not contain a nucleus and how this helps its function.

Solution:

The lack of a nucleus provides more internal space for the protein hemoglobin (HbHb).

Explanation:

By removing the nucleus, the cell can maximize the amount of hemoglobin it carries, allowing it to transport more oxygen (O2O_2) molecules to body tissues.

Problem 3:

Identify the specialized plant cell that contains the most chloroplasts and state its primary function.

Solution:

The Palisade Mesophyll cell.

Explanation:

These cells are located near the top of the leaf to capture maximum sunlight. The high concentration of chloroplasts allows the cell to perform photosynthesis efficiently, converting CO2CO_2 and H2OH_2O into glucose (C6H12O6C_6H_{12}O_6).

Specialized Cells - Revision Notes & Key Formulas | IGCSE Grade 6 Science