Plant and animal cells share a nucleus, cell membrane, cytoplasm and mitochondria. Plant cells also have three extra parts. A cell wall made of cellulose surrounds the membrane and keeps the cell rigid. Chloroplasts contain green chlorophyll, which absorbs light for photosynthesis. A large permanent vacuole holds cell sap and keeps the cell firm.
Some living things are just one cell. Bacteria are tiny cells with no nucleus; their genetic material floats in the cytoplasm. Amoeba and yeast are single cells with a nucleus. A single-celled organism must do every life process itself: move, feed, respire, grow, reproduce, sense and excrete.
Worked example
A cell has a cell wall and a nucleus but no chloroplasts. Could it be from a plant?
- Plant cells have cell walls and a nucleus.
- Root cells grow underground with no light, so they have no chloroplasts.
Answer:Yes: it could be a plant root cell.
Key words
- cell wall
- a tough outer layer of plant cells, made of cellulose
- chloroplast
- where photosynthesis happens
- vacuole
- a space full of cell sap
- unicellular
- made of a single cell
New questions every time.
NGSS-referenced: MS-LS1-2