Cell Structure, Organelles & Specialized Cells

These flashcards review cell structure, organelles, differences between plant and animal cells, and adaptations of specialised cells such as red blood cells, muscle cells, and root hair cells.

What is the living material that makes up all cells called?

Protoplasm

Name the three major parts of the protoplasm.

Cell membrane, cytoplasm, and nucleus

What two types of molecules primarily compose the cell membrane?

Lipids and proteins

Why is the cell membrane described as partially permeable?

It allows only certain small and soluble substances to pass through while restricting others.

From what substance is the plant cell wall mainly made?

Cellulose

Is the plant cell wall fully permeable, partially permeable, or impermeable?

Fully permeable

List two functions of the cell wall.

Protects the cell from injury and gives the cell a fixed shape.

What are organelles?

Specialised structures within the cytoplasm that carry out specific cellular activities.

Why is the cytoplasm considered the site of cellular activities?

It contains organelles where metabolic reactions take place.

Which organelle controls cell activities and is essential for cell division?

The nucleus

What genetic material do chromosomes contain?

DNA (deoxyribonucleic acid)

What structure separates the nucleus from the cytoplasm?

The nuclear membrane

State the main function of ribosomes.

Protein synthesis

What is the structural difference between rough and smooth endoplasmic reticulum?

Rough ER has ribosomes attached; smooth ER does not.

Describe the typical vacuole arrangement in plant versus animal cells.

Plant cells usually contain one large central vacuole; animal cells have many small, scattered vacuoles.

Give two substances commonly stored in a plant cell’s central vacuole (cell sap).

Sugars and mineral salts (also amino acids)

Which organelle is the site of aerobic respiration?

The mitochondrion

Summarise the equation for aerobic respiration inside mitochondria.

Glucose + oxygen → carbon dioxide + water + energy

Which pigment inside chloroplasts absorbs light energy?

Chlorophyll

State the overall purpose of photosynthesis carried out in chloroplasts.

To convert light energy into chemical energy stored in glucose while releasing oxygen.

Name three structural differences between typical plant and animal cells.

Plant cells have a cell wall, chloroplasts, and one large vacuole; animal cells lack cell walls and chloroplasts, and have many small vacuoles.

Define cell differentiation.

The process by which a cell becomes specialized for a specific function.

What protein in red blood cells binds to oxygen?

Haemoglobin

Explain how the biconcave shape of a red blood cell aids its function.

It increases surface-area-to-volume ratio for faster oxygen uptake.

Why do mature red blood cells lack a nucleus?

To create more space for haemoglobin and thus carry more oxygen.

Give one reason red blood cells can pass through narrow capillaries easily.

They are flexible because they lack a rigid cell wall.

Why do muscle cells contain numerous mitochondria?

To supply large amounts of energy needed for contraction.

What role do contractile protein fibres play in muscle cells?

They shorten (contract) and lengthen (relax) to produce movement.

How does the long, narrow extension of a root hair cell support its function?

It greatly increases surface-area-to-volume ratio for faster absorption of water and mineral salts.

Why is the water potential kept low inside the root hair cell’s vacuole?

A lower water potential promotes the entry of water by osmosis from the surrounding soil.