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Micro Life. Plant cells vs. Animal cells. 4). 1). 2). 5). 3). 6). Only plant cells have these:. Both types of cell have these:. Cell wall – provides support. Cytoplasm - this is where the reactions happen. Nucleus – The “brain” of the cell.
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Plant cells vs. Animal cells 4) 1) 2) 5) 3) 6) Only plant cells have these: Both types of cell have these: Cell wall – provides support Cytoplasm - this is where the reactions happen Nucleus – The “brain” of the cell Chloroplasts – contain chlorophyll Cell Membrane – holds the cell together Large Vacuole – contains sap
Cell growth Look at the pictures carefully and describe how these cells reproduce? Animal cells: Plant cells:
Cells, tissues, organs and systems Basically, all living things are made up of cells… A group of CELLS makes up a TISSUE A group of TISSUES makes up an ORGAN A group of ORGANS makes up a SYSTEM A group of SYSTEMS make up an ORGANISM
Another example Muscle cells Muscle tissue Organ System Organism Here’s another example in humans:
Microbes They can be breathed in through the mouth or nose They can be ingested (eaten) through the mouth They can enter through cuts or bites in the skin or just by touching something Microbes are micro organisms that are too small to be seen. A pathogen is a microbe that can cause diseases if it enters the body: …or other natural openings…
Disease A disease is any condition where the body isn’t working as it should. This could be caused by a malfunction in the body (as with diabetes), or it could be caused by the two types of MICROBE: Bacteria Viruses • 1/1000th mm big • Living cells (some are harmless) • Grow very quickly • Affected by antibiotics • Examples: food poisoning, tetanus, sore throats • 1/1,000,000th mm big • Genetic info inside a protein coat • Not affected by antibiotics • Release poisons • Examples: colds, flu, polio, chicken pox
Fungi Fungi are another form of microbe. There are many different varieties ranging from bread mould to mushrooms. Fungi are useful because they are natural decomposers. They also produce an important chemical called antibiotics which destroy bacteria.
Microbes: our defence against them Tears contain an enzyme that kills bacteria The skin acts as a barrier The breathing organs produce mucus to cover the lining of these organs and trap the microbes Stomach produces stomach acid If our skin is cut platelets seal the wound by clotting Our bodies have many defence mechanisms against invading microbes:
Fighting disease If microbes do enter our body they need to be neutralised or killed. This is done by WHITE BLOOD CELLS: • White blood cells do 3 things: • They eat the microbe • They produce antibodies to destroy the microbe • The produce antitoxins to neutralise the poisons produced by microbes
Producing antibodies You’re going down Step 1: The white blood cell “sees” the antigen (microbe) Step 2: The cell produces antibodies to “fit” the antigen Step 3: The antibodies fit onto the antigens and cause them to “clump” Step 4: The antigens are “eaten” by the white blood cells
Fighting disease NATURAL IMMUNITY This is when antibodies are produced by a person when needed or they are passed on by the mother during pregnancy. ARTIFICIAL IMMUNITY A vaccine with dead microbes is injected – the body is “tricked” into producing antibodies ready for the real thing.
Antibiotics What are antibiotics? Why are human cells unharmed by antibiotics? An antibiotic is a poison that works to destroy bacterial cells while leaving human cells unharmed. Antibiotics destroy the cell wall of bacteria. As viruses have no cell wall, they have no effect on viruses.
Using Antibiotics Antibiotics can be used to kill bacteria. When taking an antibiotic, you must complete the course. For example, the doctor might say that it must be taken for a full 5 days. What do you think will happen if you stopped taking the antibiotic after 2 days because you are feeling better? However, there are also problems with using antibiotics: • Overuse of antibiotics can lead to bacteria becoming resistant • Antibiotics have no effect on a virus, like the common cold. A virus must be allowed to “run its course”.