Year 10 Science: Matter, Microbes, and Machines Exam Review

Comprehensive practice flashcards covering Matter, Microbes, and Machines from the Year 10 exam review lecture.

What are the distinguishing shape and volume characteristics of a solid, a liquid, and a gas?

A solid has a fixed shape and volume; a liquid has a fixed volume and takes the shape of its container (forming a horizontal surface); a gas expands to fill its container and is easily compressed.

How do the arrangement and movement of particles differ among solids, liquids, and gases?

Solid particles are close together and vibrate about fixed positions; liquid particles are close together and move past one another; gas particles are far apart and move freely in random directions.

Why can a gas be easily compressed, whereas solids and liquids cannot?

Gas particles have large gaps between them, allowing them to be pushed closer together when force or pressure is applied.

What is the difference between a homogeneous mixture and a heterogeneous mixture?

A homogeneous mixture has a uniform composition throughout (such as sugar completely dissolved in water), whereas a heterogeneous mixture has a composition that varies from place to place (such as oil and water forming separate layers).

What are the distinct functions of the nucleus, vacuole, and chloroplast in plant cells?

The nucleus contains DNA and directs cell activities; the vacuole stores water and dissolved substances; the chloroplast carries out photosynthesis using light energy.

Which cellular structures are shared by both plant and animal cells, and what is the role of mitochondria?

Both plant and animal cells share a cell membrane, cytoplasm, nucleus, and mitochondria. Mitochondria release usable energy through cellular respiration.

What is the specific function of the cell membrane?

The cell membrane controls which substances enter and leave the cell.

How does an infectious disease differ from a non-infectious disease in cause and transmission?

An infectious disease is caused by a pathogen and can be transmitted through a suitable route (example: influenza). A non-infectious disease is not caused by a pathogen and cannot be caught from another person (example: inherited cystic fibrosis).

In this diagram of a bacterial cell, identify the structure labelled X and state its function.

Structure X is the flagellum, a long tail-like structure that helps some bacteria move.

How do fungi and bacteria differ in cell organisation and mode of reproduction?

Fungi are composed of cells containing membrane-bound nuclei and reproduce by spores or budding. Bacteria have no membrane-bound nucleus and reproduce by dividing via binary fission.

Why are antibiotics effective against bacteria but ineffective against viruses?

Antibiotics kill susceptible bacteria or inhibit their growth by targeting bacterial cellular structures. They cannot treat viruses because viruses are not cells and do not possess those bacterial targets.

What are the structural features of a virus, and how does it reproduce?

A virus is not a cell; it consists of genetic material ($\text{DNA}$ or $\text{RNA}$) surrounded by a protective protein capsid coat (and sometimes a lipid envelope). It reproduces by using a host cell to make copies.

What are the five stages of viral replication shown in this diagram?

The five stages are: 1. Attachment (virus binds to host cell), 2. Entry (viral genetic material enters), 3. Replication (host manufactures viral parts), 4. Assembly (parts join into new virus particles), and 5. Release (viruses leave to infect other cells).

What are the five main routes through which pathogens spread?

Pathogens spread via direct contact, respiratory droplets, vectors (such as mosquitoes), contaminated food, and contaminated water.

What are the body's three lines of defence against disease and how does each work?

First line: Skin forms a physical barrier to entry. Second line: Phagocytes engulf and digest pathogens. Third line: Antibodies bind specific antigens to neutralise or tag targets.

Why is an agar plate incubated upside down during microbiological culturing?

Storing the plate upside down ensures that condensation forms on the lid instead of falling onto the agar surface, preventing water droplets from spreading colonies and blurring results.

How is work calculated when force and motion act in the same direction?

Work is calculated using $W = F \times d$, where $W$ is work in joules ($\text{J}$), $F$ is force in newtons ($\text{N}$), and $d$ is displacement in metres ($\text{m}$).

How is mechanical advantage defined, and what does a value less than 1 indicate?

$\text{MA} = \frac{\text{output force}}{\text{input force}}$. An $\text{MA} < 1$ means the output force is smaller than the input effort force, which is typically traded for increased movement distance or speed.

According to the F-L-E rule illustrated, which component is in the middle for first-class, second-class, and third-class levers?

In first-class levers the fulcrum is in the middle; in second-class levers the load is in the middle; in third-class levers the effort is in the middle. (fle 123 rule)

How is the ideal mechanical advantage of a lever calculated?

$\text{Ideal MA} = \frac{\text{effort arm}}{\text{load arm}}$, where both distances are measured from the fulcrum.

How is the ideal mechanical advantage calculated for a wheel and axle and for an inclined plane?

For a wheel and axle (effort at wheel): $\text{Ideal MA} = \frac{\text{wheel radius}}{\text{axle radius}} = \frac{\text{wheel diameter}}{\text{axle diameter}}$. For an inclined plane: $\text{Ideal MA} = \frac{\text{ramp length}}{\text{vertical height}}$.

Based on this diagram, what is the formula for the ideal mechanical advantage of a screw?

$\text{Ideal MA} = \frac{\pi \times \text{Diameter}}{\text{Pitch}}$, where diameter is the effort-circle diameter and pitch is the forward distance advanced in one turn.

How is the mechanical advantage of a pulley system determined, and what is the function of a single fixed pulley?

The mechanical advantage is determined by counting the number of rope sections supporting the movable load. A single fixed pulley has an ideal $\text{MA} = 1$ and serves only to change the direction of the applied force.