3.2.1.2 Structure of Prokaryotic cells

Key differences between eukaryotic and prokaryotic cells:

• Cells are much smaller

• No membrane-bound organelles

• Smaller ribosomes (70S)

• No nucleus (singular circular DNA molecule in cytoplasm instead)

• A cell wall made of murein (a glycoprotein)

MAY ALSO CONTAIN:

• One or more plasmids

• A capsule

• One of more flagella

What do the cell wall in prokaryotic cells contain?

Contains murein, a glycoprotein

What are plasmids?

Plasmids are small loops of DNA which only carry a few genes.

Whats the structure of a capsule?

A slimy layer made of protein

What is the function of capsules?

• Prevents the bacteria from drying out

• Protects the bacteria against the host’s immune system

What is the function of the flagella?

• Rotates to enable the bacteria to move

Viruses are.. (2 keypoints)

• NON-LIVING : no metabolic reactions, cannot move, respire, and no nutrition

• ACCELULAR : not made of cells, no cell membranes

(Viruses are smaller than bacteria and only contain three structures)

What are the structures and functions of viruses?

• Genetic material : Genetic material codes for (viral) proteins

• Capsid : a protein shell that protects the genetic material/RNA/DNA

• Attachment protein : Attachment protein bind to receptors on host cell being infected