Cells (Onion cells x 400)

What is a cell? (scanning electron micrograph blood cells)

What is a cell? A cell is the very smallest unit of living matter. Human bone Mag: x 160 Bone cells are found in the dark patches on the concentric rings. All living things, including plants and animals, are made up of cells.

What is a cell? A cell is like a chemical factory.

What is a cell? There are many different kinds of cells, doing many different jobs in a plant or animal. Sperm cells

Activity 1 1. A cell 2. A cell 3. No. Plants and animals look different so the cells they are made up of should look different as well. It is the difference in cells that makes plants and animals different. 4. The cells in the skin and the cells in the muscles do different jobs. They have different shapes and structures to help them do the job.

We will focus on a few parts of the cell We will focus on a few parts of the cell. You will study this in more detail in Life Sciences Grade 10.

Cells are microscopic which means that they can only be seen with a microscope Light or Compound Microscope Electron Microscope at UCT

Animal and plant cells The two kinds you need to be most familiar with are simple animal and plant cells. Note: The cell membrane and cell wall lines should be swapped around in the plant cell

Cell parts All cells have some parts in common. Nerve cell Root epidermal cell Red blood cell White blood cell Egg cell Sperm cell Ciliated cells lining respiratory passages

Cells are three dimensional

Electron micrograph of a rat liver cell Mag: x 3700

Cell membrane One part found in all cells is the cell membrane. Note: The cell membrane and cell wall lines should be swapped around in the plant cell

Cell membrane The cell membrane surrounds the cell and holds the cell together. It controls what chemicals can enter and leave the cell. Note: The cell membrane and cell wall lines should be swapped around in the plant cell

Detailed structure of the cell membrane

Nucleus Another part found in all cells is the nucleus.

Nucleus The nucleus controls the cell. Inside the nucleus is DNA which contains genetic information.

Structure of DNA

Cytoplasm All cells also contain cytoplasm.

Cytoplasm Cytoplasm is a jelly-like mixture of chemicals where most of the work of the cell takes place.

Mitochondria Inner membrane forms cristae – increases the surface area for respiration (releasing energy from glucose)

Chloroplast Found only in plants Contain green pigment chlorophyll traps sunlight for photosynthesis