Cells

• The nucleus is the control center of the cell, containing the genetic material and regulating cell activities.
• Every living thing has cells, which are the basic building blocks of all living things.
• A cell is the basic unit of life.
• Some living organisms such as animals and plants are made of hundreds of trillions of these basic units of life called cells.
• Animal Cells -- A typical animal cell will include the nucleus, a cell membrane and a cell cytoplasm.
• The nucleus is the structure that contains the genetic information, otherwise known as DNA and it controls the actions and the reactions of the cell.
• The cell membrane, which is the border of the cell, acts as the gatekeeper and its controls what enters and exits the cell.
• As well as enabling neighbouring cells to stick to one another.
• The cell cytoplasm is the site of the cell's chemical reactions.
• Lots of chemical reactions occur here such as respiration.
• Respiration takes place in specialised structures called mitochondria.
• Plant Cells -- Plant cells contain the structures that animal cells contain, that we've just discussed, the nucleus, the cytoplasm and the cell membrane, but they also include lots of extra structures.
• Plant cells contain a cell wall which is made of cellulose and provides support for the shape of the cell.
• Plant cells contain chloroplasts which are filled with a chemical called chlorophyll, enabling plant cells to absorb light so it can be used in photosynthesis.
• Chlorophyll is also the substance that gives plants its green colour.
• Plant cells also contain structures known as vacuoles; these are filled with a watery substance which contains dissolved sugars called cell sap.
• The role of the vacuole is to provide support for the cell shape and to store sugars.
• Specialised Cells -- Some cells are specialised; they are able to carry out particular jobs.
• Red blood cells do not possess a nucleus so they have got enough space to be able to absorb and transport as much oxygen as possible.
• Nerve cells are specialised in that they have branched endings called dendrites, enabling them to communicate with lots of other nerve cells.
• White blood cells enable us to fight infections, they can be identified by the characteristic lobed nucleus and they have a flexible cytoplasm so they can engulf pathogens in a process called phagocytosis.
• Some other white blood cells are specialised to produce antibodies and it's these antibodies that fight pathogens.
• Nerve cells have long axons along which the electrical message can travel
• The cell membrane is made up of lipids and proteins
• Protein molecules embedded within the lipid bilayer
• Lipid bilayer - two layers of fatty acids joined together by hydrogen bonds