Year 9 Biology topic 1

What is the basic unit of life in multicellular organisms?

Cells

How many different types of specialized cells are in the human body?

Over 200

What do cells require for their functions?

Delivery and removal of gases, nutrients, vitamins, minerals, wastes, pH balance, and water.

What is the purpose of communication between cells in multicellular organisms?

To gain requirements and move substances throughout the body.

What are the levels of organization in multicellular organisms?

Cells, tissues, organs, and organ systems.

What is the role of sense organs?

To detect stimuli in the environment.

Name the five senses.

Sight, hearing, touch, taste, and smell.

What are stimuli?

Environmental conditions that the body must respond to, such as light, sound, touch, taste, and smell.

What are receptors?

Specialized cells in sense organs that detect and respond to specific stimuli.

What is the function of thermoreceptors?

To detect variations in temperature.

Where are thermoreceptors located?

In the brain (hypothalamus), spinal cord, abdomen, and skin.

What do mechanoreceptors detect?

Touch, pressure, sound, motion, and muscle movement.

Where can mechanoreceptors be found?

In the skin, skeletal muscle, and inner ear.

What is the role of chemoreceptors?

To detect changes in chemicals such as odors, foods/drinks, pH, and gases in the blood.

Where are chemoreceptors located?

In the nose, tongue (taste buds), brain, and heart.

What do photoreceptors detect?

Changes in light and color.

Where are photoreceptors found?

In the eyes.

What is the function of pain receptors (nociceptors)?

To detect intense stimuli and chemicals indicating danger, injury, or disease.

Where are pain receptors located?

Throughout the body, including skin, muscles, joints, and internal organs.

What is the function of the skin in terms of sense organs?

To contain receptors that detect touch and temperature.

How do chemoreceptors in the nose work?

They detect gaseous molecules dissolved in mucus, sending signals to the brain for smell interpretation.

What are taste buds and where are they located?

Taste buds contain chemoreceptors and are located within bumps called papillae on the tongue.

What are the two types of photoreceptors in the retina?

Rods (detect light intensity) and cones (detect color).

How does the ear detect sound?

Sound waves vibrate the eardrum, which is transmitted through ossicles to the cochlea, where mechanoreceptors send signals to the brain.

What is the main function of the human body systems?

To maintain coordinated balance and support the functions of cells.

What is the significance of the five senses?

They enable survival by allowing the body to detect and respond to changes in the environment.

What are the levels of organisation in multicellular organisms?

Cells, Tissues, Organs, Organ Systems, Organism

What is the basic unit of life that performs specialised roles?

Cells

What do tissues consist of?

Cells of the same kind grouped together

What is the function of organs in multicellular organisms?

Carry out specialised roles within the organism

What are organ systems?

Organs of different kinds working together to form specialised body systems

What is an organism?

The total of all organ systems working together to maintain life

How many body systems are there in humans?

11 body systems

What is the main function of the digestive system?

Breaks down nutrients into a form that can be absorbed and used by cells

What are sense organs?

Organs used to detect stimuli in the environment, including eyes, nose, ears, tongue, and skin

What are stimuli?

Environmental conditions that the body must respond to, such as light, sound, touch, taste, and smell

What are receptors?

Specialised cells in sense organs that detect and respond to specific stimuli

What do thermoreceptors detect?

Variations in temperature of internal and external environments

Where are thermoreceptors located?

In the brain (hypothalamus), spinal cord, abdomen, and skin

What do mechanoreceptors detect?

Touch, pressure, sound, motion, and muscle movement

Where are mechanoreceptors located?

In the skin, skeletal muscle, and inner ear

What do chemoreceptors detect?

Changes in particular chemicals such as odours, foods/drinks, pH, and gases in the blood

Where are chemoreceptors located?

In the nose, tongue (taste buds), brain, and heart

What do photoreceptors detect?

Changes in light and the colour of light

Where are photoreceptors located?

In the eyes

What do pain receptors (nociceptors) detect?

Intense stimuli and chemicals released by damaged or inflamed cells indicating danger, injury, or disease

Where are pain receptors located?

Throughout the body, including skin, muscles, joints, and internal organs

What is the role of the skin in the sense of touch?

Contains pain receptors and mechanoreceptors that detect sharpness and touch

How does the nose contribute to the sense of smell?

Chemoreceptors detect gaseous molecules dissolved in mucus and send messages to the brain

What are taste buds and where are they located?

Contain chemoreceptors and are located within bumps called papillae across the tongue

What are the two types of photoreceptors in the retina?

Rods (detect light intensity) and cones (detect colour)

How do ears detect sound?

Mechanoreceptors in the inner ear detect vibrations caused by sound waves and send messages to the brain

What is the function of the auditory nerve?

Transmits sound information from the inner ear to the brain for interpretation