Example 1
Which phospholipid region faces the cytosol?
The hydrophilic heads face the watery cytosol. The hydrophobic tails point inward toward other tails.
BUILD FLUENCY. EARN YOUR ASCENT.Sign in
Year 12 · SACE Stage 2
Membrane architecture and organelle functions
Match membrane regions and organelle structures to their named roles.
Method and worked examples
A phospholipid has a water-attracting hydrophilic head and water-avoiding hydrophobic tails. In a bilayer, heads face the watery cytosol and external fluid; tails face one another inside the membrane. Embedded proteins provide functions such as transport and signalling. The bilayer does not consist of a row of heads with every tail exposed to water.
For organelle matching, distinguish storage, production and transport. The nucleus contains nuclear chromosomes; the nucleolus assembles ribosomal components. Rough ER supports many membrane and secreted proteins; smooth ER supports lipid synthesis. Golgi modifies and sorts cargo, lysosomes digest materials, and vacuoles store substances. The cytoskeleton supports shape and intracellular movement. Mitochondria support aerobic respiration; chloroplasts perform photosynthesis.
Example 1
Example 2
Match nucleus, nucleolus and ribosome with DNA storage, ribosomal-component assembly and translation.
Nucleus: nuclear DNA storage. Nucleolus: ribosomal-component assembly. Ribosome: translation. These are distinct structures and functions.
Watch out: Hydrophobic tails face inward; hydrophilic heads face the watery environments.