THE NATURE AND VARIETY OF LIVING ORGANISMS

Flashcards of key vocabulary terms and definitions from the transcript.

Characteristics

Features which allow us to recognise something for what it is.

Nutrition

Plants make their own food, animals eat other organisms

Respire

Release energy from their food

Excrete

Get rid of waste products

Respond to stimuli

Are sensitive to changes in their surroundings

Control their internal conditions

Maintain a steady state inside the body

Reproduce

Produce offspring

Grow and develop

Increase in size and complexity, using materials from their food.

Plants

Multicellular organisms with chloroplasts that perform photosynthesis and have cell walls made of cellulose.

Photosynthesis

The process that uses light energy to convert water and carbon dioxide into organic substances.

Vertebrates

Animals with a backbone (vertebral column).

Invertebrates

Animals without a backbone.

Glycogen

A substance in which animals store carbohydrate.

Fungi

Organisms with cell walls made of chitin that do not photosynthesize; includes mushrooms, molds, and yeasts.

Hyphae

Thread-like filaments that make up the network of a mould.

Mycelium

The network of hyphae that forms the main body of a fungus.

Saprotrophic nutrition

Nutrition by absorbing nutrients from dead organic material, with digestion taking place outside the organism.

Extracellular enzymes

Enzymes that are secreted out of cells to break down food.

Protoctists

A diverse group of mainly microscopic, single-celled organisms which are neither plants, animals nor fungi.

Protozoa

Protoctists that resemble animal cells, such as Amoeba.

Algae

Protoctists that have chloroplasts and carry out photosynthesis, similar to plants.

Eukaryotic organisms

Organisms composed of eukaryotic cells, which contain a nucleus and membrane-bound organelles.

Eukaryotic

Cells 'having a nucleus'.

Prokaryotic organisms

Organisms made of simpler cells without a nucleus or membrane-bound organelles.

Prokaryotic

Cells 'before nucleus'.

Bacteria

Small, single-celled organisms with a cell wall, cell membrane, and cytoplasm, but no nucleus.

Plasmids

Small circular rings of DNA found in bacteria, carrying some of the bacterium's genes.

Pathogens

Organisms that cause disease.

Viruses

Parasitic entities that can only reproduce inside living cells; composed of genetic material and a protein coat.

Host

The cell in which a virus lives.

Ribonucleic acid (RNA)

A chemical similar to DNA.