B6 - Bacteria

Question 1

What can be the 4 shapes of a bacteria cell?

Answer 1

Rods

Curves rods

Spheres

Spirals

Question 2

What is a flagellum and where is it found?

Answer 2

The flagellum is found in a bacteria cell

It is a tail that helps the bacteria to move around.

Question 3

Explain each structure of a bacteria. What is it made off?

Answer 3

• cell wall :

Helps to keep their shape and not burst

• one strand of DNA :

Found in the cytoplasm and control cell’s activities and replication

• plasmid :

Many small loops of DNA

• cell membrane
• cytoplasm

Question 4

Why can bacterias survive in almost any habitat? E.g. Soil, water, air, food and human body.

Answer 4

They can consume a range of organic nutrients from any surrounding. (Some can even produce their own!)

These nutrients provide them with energy which helps them survive everywhere.

Question 5

How do bacteria reproduce?

Answer 5

By asexual reproduction

• a binary fission (split in two) and become clones of each other.

Question 6

How fast do bacteria reproduce and when is their optimum state of reproducing?

Answer 6

-Bacterias reproduce really fast

(if a disease-causing bacteria enter your body, it will cause the disease before your body respond to it)

• Reproduced even faster when its warm and there is a good source of nutrients

(This is why food should be stored carefully and sometime put in fridge as it will slow down the reproducing of bacteria)

Question 7

Why is aseptic technique?

Answer 7

Used for culturing (growing) bacteria on an agar plate (Petri dish containing agar jelly)

Question 8

How does aseptic technique work?

Answer 8

• aseptic technique is used to protect yourself from infection
  1) wear gloves and tie up hair
  2) sterilise equipment before and after use (using a Bunsen burner to sterilise the inoculation loop after use)
  3) sealing the dish once transferred the bacteria inside it.
  4) disposing the bacteria safely after use - done by pressure sterilising

Question 9

What other things can bacteria be used for?

Answer 9

Making yoghurt

Question 10

How do you make yoghurt using bacteria?

Answer 10

1) sterilise equipment to kill off unwanted microorganismes
2) milk is pasteurised (heated up to 72C to kill unwanted microorganismes) then cooled down.
3) lactobacillus bacteria is added
4) mixture is incubated (heated to 40C) in a fermenter.
5) bacteria break down the lactose sugar in milk into lactic acid.
6) sample is taken to make sure is it at the right consistency. Flavour is added and colour too