Cells Learning Objectives 1 To revise basic cell structure To revise cells tissues and organs 3 That chemical reactions in cells are controlled by enzymes using the example of the mitachondrion

Learning Outcomes All can describe the structure and function of the organelle of animal cells Most can describe the major organs and tissues of the body Some can explain that enzymes control cell reactions using the example of the mitachondrion and respiration

How big is a cell? Most plant and animal cells are between 0.025 µm and 60 µm in size – around half the diameter of a human hair – and too small to see without a microscope. The largest cell in the human body is the female egg cell, (ovum) at around 1,000 µm in diameter. Photo credit: Eye of Science / Science Photo Library Coloured scanning electron micrograph (SEM) of sperm (blue) attempting to penetrate a human egg (red). Each sperm (spermatozoa) has a rounded head and a long tail with which it swims. Women usually release one egg (ovum) per month, whereas men release millions of sperm in each ejaculation. Only one of these sperm can penetrate the egg's thick outer layer (zona pellucida) and fertilise it. Fertilisation occurs when the sperm's genetic material (deoxyribonucleic acid, DNA) fuses with the egg's DNA. When this occurs the egg forms a barrier to other sperm. Magnification: x650 when printed 10 centimetres wide. Teacher notes One micrometer (µm), also known as a micron, is equal to one-millionth of a meter. 1 µm = 0.000001 m. The smallest human cell is the sperm cell – the head is around 5 µm long.

What do cells contain? Teacher notes This activity could be used to gauge students’ existing knowledge of the major organelles in animal and plant cells.

Exploring animal cells Teacher notes This click and reveal activity could be used to check students’ understanding of the organelles found in animal cells.

What is aerobic respiration? Aerobic respiration is a series of reactions that release energy from glucose using oxygen.  + oxygen carbon dioxide water glucose energy : Aerobic Respiration takes place in mitochondria. Teacher notes See the ‘Animal and Plant Cells’ presentation for more information about mitochondria and respiration. Mitochondria are the energy-producing part of the cell.

How do animal cells specialize? In animals, the first type of cells in the developing embryo are stem cells. These are unspecialized cells that go on to form all the different cell types in the adult. stem cell red blood cell sperm cell Teacher notes See the ‘Growth and Development’ presentation for more information about stem cells and human growth. nerve cell muscle cell

How are animal cells adapted? Teacher notes This click and reveal activity could be used to check students’ understanding of animal cell structures and function.

Exploring plant cells Teacher notes This click and reveal activity could be used to check students’ understanding of the organelles found in plant cells.

How do plant cells specialize? Unlike animals, many plant cells retain the ability to differentiate and specialize throughout their life. These cells are found in tissues called meristems. meristem cell root cell leaf cell Teacher notes See the ‘Growth and Development’ presentation for more information about meristems and plant growth. sieve cell

Plant cells: fit for a purpose Teacher notes This matching activity could be used as a plenary or revision exercise on plant cells. Students could be asked to complete the questions in their books and the activity could be concluded by the completion on the IWB.