BACTERIA
BACTERIA CAN BE EXTREMELY HELPFUL AND EXTREMELY HARMFUL
HELPFUL
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HARMFUL
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Basic Bacterial structure
Bacteria are unicellular organisms that are found in so many places - we don't actually realize the extent to which they live. There thousands found inside and on us!
Bacteria all contain some DNA however it is not found within a nucleus - it just floats around the cytoplasm. Bacteria have both a cell wall and a cell membrane. They also have a slime capsule which offers them protection. Bacteria have one main organelle, ribosomes, which produce proteins (needed to make enzymes and have many other functions). They may also contain aflagella (tail). They are incredibly small and can only be seen under a microscope, unless grown in colonies on an agar plate - which we can see because there are so many. |
LIFE PROCESSES
Like all other living things, bacteria must carry out MRSCGREN in order to live! We are only going to focus on 5 of these processes
Bacterial Nutrition
BACTERIA CAN BE AUTOTROPHS OR HETEROTROPHS
AUTOTROPH
Some species of bacteria can actually make their own food, just like plants! These types of bacteria can be referred to as autotrophic, or autotrophs.
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HETEROTROPH
Many bacteria are heterotrophs - they can only gain nutrients from eating and digesting other organic (living, was once living) material. If bacteria gain their nutrients from dead or decaying matter, they are called saprotrophs. Other bacteria can gain nutrients from eating living organisms - they are just called heterotrophs.
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PARASITISM
When a bacterium lives and feeds off living matter, causing harm to that organism, the bacterium is called a 'parasite'
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MUTUALISM
Some bacterium have a relationship with their host where they both benefit (e.g. bacterium inside the gut of herbivores) - these bacteria are called mutualists
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COMMENSALISMBacteria that do neither harm nor good to their host are called commensals - for example bacteria that live on our skin
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Heterotrophic Bacteria Must Break Down (Digest) the Organic Matter of Other Organisms. They do This Using a Process Called Extra-Cellular Digestion.
Extra-cellular means outside of the cell therefore the breakdown of nutrients actually occurs outside the bacteria.
.There are 3 steps to this process.
1. Enzymes are made and secreted (released) onto the food source. 2. The enzymes break down the organic matter by speeding up the catabolic ("breaking-down") reactions that must occur. 3.The enzymes and digested nutrients are absorbed back into the bacterial cell via active transport. From here, the bacterial cell can use the nutrients to fuel any processes that require energy (e.g. movement and reproduction). Note: active transport is the bulk-movement of substances across a semi-permeable membrane, requiring energy. Here is a complete guide to dispose of dead animals like cat dog etc. |
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