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Eukaryotic Cells Divide Labour Among Membrane-Bound Organelles

1. A eukaryotic cell keeps its DNA inside a nucleus and splits its work among separate organelles.
2. Each organelle handles one job, and together they keep the whole cell alive.

The Plasma Membrane Controls What Enters and Leaves

1. The plasma membrane regulates the exchange of substances, letting nutrients in and waste out.
2. It keeps the inside of the cell stable and maintains homeostasis.
3. It also carries receptors for cell communication with the surroundings.

The Cytoplasm Is Where Most Reactions Happen

1. The cytoplasm is the site of many metabolic reactions.
2. It holds the organelles, allowing compartmentalisation so different reactions run at once in separate places.

80S Ribosomes Build the Cell's Proteins

1. Ribosomes are found free in the cytoplasm or attached to the rough endoplasmic reticulum.
2. They translate mRNA into proteins that the cell needs to grow and work.

The Nucleus Stores DNA and Directs the Cell

1. The nucleus holds linear chromosomes made of DNA wound around histone proteins.
2. The nuclear envelope has pores that control which RNA and proteins pass through.
3. It directs the cell by controlling gene expression and passing on genetic information during cell division.

Membrane-Bound Organelles Separate the Cell's Jobs

Mitochondria Release Energy for the Cell

1. The inner membrane folds into cristae that increase the surface area for energy release.
2. The matrix holds the enzymes for the Krebs cycle and other pathways.

The Endoplasmic Reticulum Makes and Moves Molecules

1. The endoplasmic reticulum is a network of membranes that moves materials through the cell.
2. Rough ER is studded with ribosomes and makes proteins for secretion or for membranes.
3. Smooth ER has no ribosomes and handles lipid synthesis, detoxification, and calcium storage.

The Golgi Apparatus Modifies and Ships Products

1. The Golgi apparatus modifies molecules, for example by adding sugars to proteins.
2. It then packages them into vesicles for delivery.

Vesicles, Lysosomes and Vacuoles Store and Recycle Materials

1. Vesicles are small membrane sacs that store or transport substances.
2. Lysosomes hold hydrolytic enzymes that digest waste and pathogens.
3. The large central vacuole, prominent in plant cells, stores water and ions and provides turgor pressure.

The Cytoskeleton Gives Shape and Guides Transport

1. The cytoskeleton is a network of fibres that supports the cell and moves things around inside it.
2. Microtubules are hollow tubes that hold the cell's shape and act as tracks for organelle movement.
3. Microfilaments are thin fibres that support shape and enable movement, such as in muscle cells.

Chloroplasts Capture Light Energy for Photosynthesis

1. Chloroplasts have a double membrane with internal thylakoid membranes stacked into grana.
2. They are the site of photosynthesis, and they occur in plant and algal cells.

The Organelles Work Together as One System

1. The plasma membrane controls exchanges with the environment.
2. The nucleus directs the cell, and the mitochondria supply energy.
3. The ER, Golgi apparatus, and vesicles handle production, packaging, and transport.