Every cell contains a plasma membrane, cytoplasm, genetic material, and ribosomes, providing controlled exchange, metabolic space, inherited information, and protein synthesis.
All cells have a plasma membrane, cytoplasm, ribosomes and genetic material, even though their shapes and internal compartments differ.
The membrane separates the internal reaction space, cytoplasm contains soluble chemistry, ribosomes make polypeptides, and DNA or equivalent genetic material stores instructions. These shared features support the cell-theory definition of a cell.
When identifying a cell, look for:
A prokaryotic cell lacks a nucleus but still has DNA, ribosomes, cytoplasm and a plasma membrane.
A nucleus is not a universal cell feature; it is a eukaryotic compartment.
This objective is assessed through structured response, commonly using Identify / Compare / Contrast.
Identify / Compare / Contrast
Build the answer around this relationship: A plasma membrane encloses every cell and regulates exchange.
Naming a nucleus or membrane-bound organelle as a structure present in every cell.
Representative question
List two structures that neurons have in common with prokaryotic cells.
a. DNA/chromosomes;
b. ribosomes;
c. plasma/cell membrane/phospholipid bilayer;
d. cytoplasm/cytosol;
2
Marking guidance:
max
The SL core is a practical chain. First, understand cells as structural and functional units. Then use microscopes correctly: prepare, stain, calibrate, measure, and choose a method based on resolution and the detail needed. Finally, identify cell types from visible evidence and draw only what the micrograph shows. This is how the topic turns from definitions into exam performance.