# Explain how the structure of the Golgi apparatus is related to its function in the processing and secretion of proteins.

> IB DP Biology Standard Level (2023 syllabus) — B2.2 Organelles and compartmentalisation · Explain · 4 marks

## Mark scheme (4 marks)

1. The Golgi apparatus consists of a stack of flattened membrane-bound cisternae, providing a series of distinct compartments for the sequential modification of proteins.
2. Proteins enter the cis face (from the rER via vesicles) and exit from the trans face, ensuring directional flow and correct order of modifications such as glycosylation or phosphorylation.
3. The Golgi membrane can bud off small transport vesicles that carry processed proteins to their correct destinations, such as the plasma membrane, lysosomes, or outside the cell via exocytosis.
4. Compartmentalisation within the Golgi cisternae maintains distinct chemical environments (e.g. different enzymes in each cisterna), allowing specific and efficient modifications without interference from other cellular reactions.

## Key terms

- [Golgi apparatus](https://www.gradenine.co.uk/glossary/golgi-apparatus)

## Related

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Source: [GradeNine](https://www.gradenine.co.uk/q/explain-how-the-structure-of-the-a99f0a0f) · Published by Druglandscape Ltd.