B6 Flashcards
Compare bacteria cells to animal cell:
Bacteria are smaller and simpler than animal cells.
Why do Bacteria have a cell wall?
To stop the cell from bursting and to retain it’s structure.
What is the flagellum used for?
To help them swim/move.
What are the four types of bacteria?
1)Rods 2)curved rods 3)spheres 4)spirals.
How do bacteria reproduce?
Asexual reproduction which means that they are clones from one bacterium splitting.
What increases bacteria’s r. of reproduction?
Warm and a high source of nutrients.
What technique should be used for culturing bacteria?
Describe how to do this:
Aseptic.
1) Get a petri dish and put some agar jelly on it.
2) Pass the inoculation loop through the bunsen flame whilst wearing gloves and place the bacteria on the agar jelly.
How do viruses reproduce?
They can only reproduce inside living cells.
1) Virus latches onto a living cell and pierce the host cell, injecting it with its genetic material.
2) The host cell then reproduces the viruses causing the cell to burst, setting the viruses free to continue this cycle.
What are the 4 x disease transmissions?…with examples.
1) In food:contaminated with bacteria e.g. food poisoning
2) In water:contaminated with bacteria(usually sewage)e.g. Cholera.
3) Airborne:Viruses can be spread into the air e.g. by sneezing e.g. Influenza
4) Contact: Fungi can be picked up by a host were an infected person has been e.g. athlete’s foot.
Antibiotics can only…
cure bacteria infections not viral infections.
How can bacteria evolve to become resistant?
By randomly mutating their DNA which leads to changes in the bacteria’s characteristics sometimes making them more resistant to certain types of antibiotics. As these bacteria can’t be killed off, they reproduce more creating a resistant gene.
1) What did Pasteur discover?
Discovered that microbes were in the air.
2)What did Lister do?
Discovered that microbes can infect open, un-cleaned wounds-began to treat wounds with antiseptic carbolic acid.
3)What did Fleming do?
Discovered antibiotic: Penicillin by accident as whilst cleaning petri dishes he noticed that the bacteria didn’t grow where mould was.
What useful thing does Bacteria make?with technique.
Yogurt:
1) Sterilise all equipment.
2) Then pasteurise the milk at 72’c to kill bacteria.
3) Then a starter culture is added. This is incubated in a fermenter. The bacteria then break down the lactose sugar in the milk into lactic acid. This causes the milk to clot.
4) A sample is taken to see if ok. Then flavours e.t.c. are added.
