Specialised cells

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课程笔记

What are specialised cells?

Many cells look similar, but some have special features that help them perform unique jobs.
These are called specialised cells.

Root hair cells

Function: Absorb water and nutrients from the soil to help a plant grow.
Adaptation: Long, hair-like projections increase surface area for efficient absorption.

Sperm cells

Function: Fertilise an egg cell (ovum) for reproduction.
Adaptation: Long tail (flagellum) helps them swim toward the egg.
Adaptation: Streamlined shape and head containing enzymes to penetrate the egg.
Adaptation: Head contains the cell's genetic material.

Nerve cells (neurons)

Function: Transmit electrical signals throughout the body to control body functions, send messages from the brain, and respond to stimuli.
Adaptation: Long extensions called axons and dendrites connect with other nerve cells to transmit signals quickly over long distances.

Muscle cells

Function: Produce movement by contracting and relaxing in response to signals from the nervous system.
Adaptation: Long and can change shape by contracting.
Adaptation: Contain many mitochondria to provide energy for contraction.

Red blood cells

Function: Carry oxygen in the blood to the rest of the body.
Adaptation: Biconcave shape increases surface area for absorbing oxygen.
Adaptation: Small and flexible to fit through tiny blood vessels.

Examples of specialised cells: sperm, nerve, red blood, root hair, and muscle cells.

幻灯片

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练习题

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1.Which of the following is true about specialised cells?
Easy
- AThey have special features to perform unique jobs
- BThey all have the same shape and size
- CThey cannot perform any specific function
- DThey are only found in animals
2.Which of the following cells has a long tail called a flagellum?
Easy
- ASperm cell
- BRed blood cell
- CRoot hair cell
- DNerve cell
3.True or false: Red blood cells have a long tail to help them swim through blood.
Easy
- AFalse
- BTrue
- CCannot tell
- DOnly in some animals
4.Root hair cells are adapted to absorb water and nutrients by having:
Easy
- ALong, hair-like projections that increase surface area
- BA long tail for swimming
- CMany mitochondria for energy
- DA biconcave shape
5.Why do muscle cells contain many mitochondria?
Medium
- ATo provide energy for contraction
- BTo increase surface area for oxygen absorption
- CTo help them swim
- DTo transmit electrical signals
6.Which cell type is responsible for carrying oxygen in the blood?
Easy
- ARed blood cell
- BWhite blood cell
- CNerve cell
- DMuscle cell
7.Nerve cells have long extensions called axons and dendrites. What is the main function of these extensions?
Medium
- ATo connect with other nerve cells and transmit signals quickly over long distances
- BTo absorb water and nutrients
- CTo contract and relax
- DTo carry oxygen
8.Which of the following is NOT a specialised cell mentioned in the source?
Easy
- AWhite blood cell
- BSperm cell
- CRoot hair cell
- DMuscle cell

复习笔记

## Specialised Cells Specialised cells have unique features that help them perform specific functions. ### Root Hair Cells - **Function**: Absorb water and nutrients from soil. - **Adaptation**: Long, hair-like projections increase surface area for efficient absorption. ### Sperm Cells - **Function**: Fertilise an egg cell (ovum) for reproduction. - **Adaptations**: - Long tail (flagellum) for swimming. - Streamlined shape. - Head contains enzymes to penetrate egg and genetic material. ### Nerve Cells (Neurons) - **Function**: Transmit electrical signals to control body functions, send messages, and respond to stimuli. - **Adaptations**: Long extensions (axons and dendrites) connect with other nerve cells for fast signal transmission over long distances. ### Muscle Cells - **Function**: Produce movement by contracting and relaxing in response to nervous system signals. - **Adaptations**: - Long shape, can contract. - Contain many mitochondria to provide energy for contraction. ### Red Blood Cells - **Function**: Carry oxygen in blood to the body. - **Adaptations**: - Biconcave shape increases surface area for oxygen absorption. - Small and flexible to fit through tiny blood vessels. **Key Points**: - Specialised cells have distinct shapes and sizes adapted to their roles. - Root hair cells are for plants, not human hair. - Red blood cells lack a tail; they are biconcave. - Sperm cells fertilise eggs. - Nerve cells transmit electrical signals. - Muscle cells contract using energy from mitochondria.

Specialised cells: Cells with special features that help them perform unique jobs.
Root hair cells: Plant cells with long, hair-like projections that absorb water and nutrients from soil.
Sperm cells: Male reproductive cells with a flagellum, streamlined shape, and enzymes to fertilise an egg.
Nerve cells (Neurons): Cells with long axons and dendrites that transmit electrical signals throughout the body.
Muscle cells: Long cells that contract and relax to produce movement, containing many mitochondria for energy.
Red blood cells: Biconcave, flexible cells that carry oxygen in the blood.
Flagellum: A long tail-like structure that helps sperm cells swim.
Axon: A long extension of a nerve cell that transmits signals away from the cell body.
Dendrite: An extension of a nerve cell that receives signals from other cells.
Mitochondria: Organelles that provide energy for cell functions, abundant in muscle cells.
Biconcave: A shape that is curved inward on both sides, increasing surface area for oxygen absorption in red blood cells.

闪卡

What are specialised cells?

Cells that have special features to help them perform unique jobs.

What is the function of root hair cells?

They absorb water and nutrients from the soil to help a plant grow.

How are root hair cells adapted for absorption?

They have long, hair-like projections that increase surface area for efficient absorption.

What is the function of sperm cells?

They fertilise an egg cell (ovum) for reproduction.

What is the flagellum on a sperm cell?

A long tail that helps the sperm swim toward the egg.

What does the head of a sperm cell contain?

Enzymes to help penetrate the egg cell and the cell's genetic material.

What is the function of nerve cells (neurons)?

They transmit electrical signals throughout the body to control functions, send messages, and respond to stimuli.

What are axons and dendrites?

Long extensions of nerve cells that connect with other nerve cells to transmit signals quickly over long distances.

What is the function of muscle cells?

They produce movement by contracting and relaxing in response to signals from the nervous system.

How are muscle cells adapted for contraction?

They are long and can change shape by contracting; they contain many mitochondria for energy.

What is the function of red blood cells?

They carry oxygen in the blood to the rest of the body.

How are red blood cells adapted for oxygen transport?

They have a biconcave shape that increases surface area for absorbing oxygen, and are small and flexible to fit through tiny blood vessels.

True or false: Specialised cells have the same shape and size as all other cells.

False.

True or false: Red blood cells have a long tail to help them swim through blood.

False.

True or false: Sperm cells fertilise an egg cell for reproduction.

True.

True or false: Electrical signals are transmitted through nerve cells.

True.

True or false: Red blood cells have a large surface area for carrying oxygen.

True.

True or false: Root hair cells are responsible for hair growing on humans.

False.

True or false: Muscle cells contract and relax in response to signals from the nervous system.

True.

True or false: Root hair cells help plants absorb sunlight.

False.

Why do muscle cells contain many mitochondria?

To provide the energy needed for contraction.

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