Uh science 9 ig

Cells ig

Science | cells
Cells
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Cells

- [ ] A cell is the smallest living organism and the basic cell unit of life on earth.

- [ ] trillions of these cells make up the human body.

- [ ] Cells have three parts: membrane, nucleus and cytoplasm.

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Nucleus

- [ ] Nucleus resembles the headquarters, there is 1 per cell. unless it's a skeleton muscle cell, in which case there would be 2

- [ ] The nucleus contains majority of the cells DNA, and mitochondria house a small amount.

- [ ] The nucleus sends messages to tell the cell to grow, divide, or die.

- [ ] A membrane called nuclear envelope, separates the nucleus from the rest of the cell.

- [ ] nuclear pores within the membrane allow small molecules and ions to cross back and forth, while larger molecules need to transport proteins to help them through.

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Plasma membrane

- [ ] To make sure all the cells remain separate from there neighbours, the plasma membrane envelopes the cell.

- [ ] Phospholipids make most of this membrane and prevent water-based liquids from entering the cell.

- [ ] The plasma membrane contains a range of receptors, which carry out a number of tasks, including being

Gatekeepers: some receptors allow certain molecules through and stop others

Markers: these receptors act as name badges, informing the immune system that they are part of the organism and not foreign invaders.

Communicators: some receptors help the cell communicate with other cells and the environment.

Fasteners: some receptors help bind the cell to its neighbours.

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Cytoplasm

- [ ] The cytoplasm is the interior of the cell that surrounds the nucleus.

- [ ] It includes the organelles and jelly like fluid called the cytosol.

- [ ] Many of the important reactions that take place in the cell occur in the cytoplasm.
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