Microbes · Chapter 2: Bacteria and how they live

Year 11 SCX · About 17 minutes with activities · Turn your sound on

Chapter 2 · Bacteria and how they live

Day 0: one celltoo small to see

Day 2: millionsa colony you can see

Feedsextracellular digestion

Excretesdiffusion

Respiresreleases ATP

Multipliesbinary fission

Naked eyetoo small to see

Microscopebacteria visible

Every corner of Earth

Nutrient agarjelly full of food

Fungifluffy, thread-like

Bacteriagreasy, shiny, smooth

Cytoplasmchemical reactions

DNAgenetic material

Cell membranecontrols entry and exit

Cell wallstructure, protection

Slime capsuleprotection

Flagellummovement

1 DNA copies

2 Cell elongates

3 Pinches in half

4 Two cellsidentical

Enzymes secreted

Large food molecule

Smaller molecules

Absorbedinto the cell

Inside: highlots of waste

Outside: lowlittle waste

Diffusion: high → low

Active transportlow → high, uses energy

Chapter 2 recap

Microorganism: an organism too small to be seen with the naked eye. Culture bacteria and fungi on nutrient agar, incubated upside down at 25 °C or below (no human pathogens; condensation can’t drip). Fungal colonies are fluffy and thread-like; bacterial colonies are greasy, shiny, smooth spots.
Bacterial cell: cytoplasm (chemical reactions), DNA (genetic material, a single loop), cell membrane (controls entry and exit), cell wall (structure and protection), slime capsule (protection), flagellum (movement).
Life processes: binary fission (DNA copies → cell elongates → membrane pinches → two identical bacteria); extracellular digestion (secrete enzymes → digest outside → absorb); excretion by diffusion (high → low); respiration: glucose + oxygen → carbon dioxide + water + ATP (aerobic, more ATP) or glucose → lactic acid + ATP (anaerobic).
Next: Chapter 3 · Enzymes

How does a single cell feed, breathe and multiply?

Chapter 2 · About 17 minutes · sound on

0:00

Voice In Chrome this uses Google’s voice; other browsers use the recorded voice. Your choice here is remembered.