Biology 8 Review

Characteristics of Life

100

List 3 characteristics of living things

3 of: cells, nutrients, energy, waste, respond, grow, reproduce

200

Which is NOT a characteristic of life?
a) Uses energy
b) Made of cells
c) Made of sunlight
d) Produces waste

c) Made of sunlight

300

What does it mean to “respond to stimuli”? Give an example

The ability of a living organism to detect, interpret, and react to changes in its internal or external environment.

• A plant grows toward light
• You pull your hand away from something hot
• Your stomach growls → you eat
• Pupils shrink in bright light
• You shiver when cold 

400

Is wood alive? Give ONE reason why or why not

Not alive (doesn’t meet all characteristics)

500

Explain the difference between growth and reproduction

• Growth = getting bigger (more cells or size)

• Reproduction = making new organisms

• Growth happens within one organism; reproduction creates a new one

• Growth increases size; reproduction increases population

Cells & Organelles

100

What is the basic unit of life?

cells

200

Which organelle controls what enters and leaves the cell?

Cell membrane

300

Which organelle releases energy from food?

Mitochondria

400

Which organelle is ONLY found in plant cells and makes food?

Chloroplast

500

Give an analogy for the nucleus and explain why.

Examples:

• Brain → controls everything

• Principal → directs activities

• Control center → gives instructions

• Boss → tells cell what to do

Cell Types

100

Which type of cell has a nucleus?

Eukaryotic

200

Which type of cell is bacteria?

Prokaryotic

300

Give ONE difference between plant and animal cells.

• Plant cells have chloroplasts; animal cells don’t

• Plant cells have a cell wall; animals don’t

• Plant cells can photosynthesize; animals cannot

• Plant cells are more rigid; animal cells more flexible

400

Give TWO differences between prokaryotic and eukaryotic cells

• Prokaryotes have no nucleus; eukaryotes do

• Prokaryotes are simpler; eukaryotes more complex

• Prokaryotes are smaller; eukaryotes larger

• Prokaryotes don’t have membrane-bound organelles; eukaryotes do

500

Why do plant cells have chloroplasts but animal cells do not?

Plants make their own food (photosynthesis)

Microbes & Disease

100

What is a pathogen?

A microbe that causes disease

200

Give ONE positive effect of microbes

• Help digest food (gut bacteria)

• Make foods (yogurt, cheese, bread)

• Produce medicines (antibiotics, insulin)

• Help prevent harmful bacteria

300

Give ONE negative effect of microbes

• Cause disease (pathogens)
• Food poisoning
• Food spoilage (mould)
• Produce toxins (red tide) 

400

What is an epidemic?

Disease spreading above normal in a region

500

Explain how “superbugs” form

• Some bacteria survive antibiotics

• These resistant bacteria reproduce

• Over time, most bacteria become resistant

• Caused by overuse/misuse of antibiotics

Immune System & Vaccines

100

What is the first line of defense?

Skin/barriers

200

What do white blood cells do?

Fight pathogens

300

What is immunity?

• Body remembers pathogens

• Faster response next time

• You don’t get as sick or don’t get sick

• Specialized white blood cells recognize pathogens

400

Why don’t antibiotics work on viruses?

Viruses are not alive

500

How does a vaccine work?

• Contain weakened or dead pathogens

• Trigger immune response

• Body “remembers” the pathogen

• Helps fight it faster later

• Types: weakened, killed, pieces (subunit), toxoid