biology

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calculating magnification size of a cell

Magnification = image size ÷ cell size

difference between a plant cell and an animal cell

The key differences between a plant cell and an animal cell are:

1. Cell Wall: Plant cells have a rigid cell wall outside the cell membrane, providing structural support and protection. Animal cells lack a cell wall.

2. Chloroplasts: Plant cells contain chloroplasts, which are essential for photosynthesis. Animal cells do not have chloroplasts.

3. Vacuole: Plant cells typically have one large, central vacuole that stores water, nutrients, and waste, and helps maintain turgor pressure. Animal cells may have several small, temporary vacuoles, or none at all.

4. Centrioles: Animal cells have centrioles, which are involved in cell division. Plant cells typically lack centrioles.

5. Shape: Plant cells often have a fixed, rectangular, or cube-like shape due to the cell wall. Animal cells tend to have an irregular or rounded shape.

6. Energy Storage: Plant cells store energy as starch, while animal cells store energy as glycogen.

specialised cells

• ciliated cells (movement of mucus in the trachea and bronchi)

• root cells (absorption)

• palisade mesophyl cells (photosynthesis)

• neurones (conduction of electrical impulses)

• red blood cells (transport of oxygen)

• sperm and egg cells (reproduction)

Diffusion

• Net Movement: Although individual particles move randomly, the overall (net) movement is from high to low concentration.

• Concentration Gradient: The difference in concentration between two regions drives diffusion.

• Random Motion: Particles move in all directions due to kinetic energy, but statistically more particles move from crowded areas to less crowded ones.

• No Energy Required: Diffusion is a passive process and does not require cellular energy (ATP).

substances move into and out of cells by diffusion through the cell membrane. This process allows particles such as oxygen, carbon dioxide, and small lipid-soluble molecules to passively cross the membrane from areas of higher concentration to areas of lower concentration, without the need for energy.