Bacteria Flashcards
What is mainly different about bacteria from viruses?
Bacteria are complete life forms with all characteristics of living organisms
Where can bacteria be found on earth?
Soil,water and other living organisms in the depth of the ocean
What sizes can bacteria vary from?
0.0005mm to 0.005mm
What is the function of the cell wall of a bacterium?
It gives a bacterium its shape and protects its cytoplasm from the external environment
The cell wall has pores in it which allow dissolved substances to move in and out of the bacterium cell
What can sometimes be found covering the outside of the cell wall
Slime capsule
What is the function of the slime capsule found covering the outside of the cell wall?
It protects the bacteria against digestive enzymes and the immune system of the host
How is the layer of slime found covering the outside of the cell wall created?
It is secreted by the bacterium through its cell wall
Where can the slime capsule be found?
Around parasitic bacteria while they are inside the host
Are some bacteria motile?
Yes
How are bacteria able to move ?
They propel themselves through liquids by means of whip-like movements of one or more flagella
What is the function of the cell membrane in the bacterium cell?
It enclosed the cytoplasm
It is selectively permiable and therefore regulates the substances that pass into and out of it’s cytoplasm
What does the cytoplasm of bacterium cells contain?
Ribosomes
What is the function of ribosomes inside a bacterium cell?
Manufacture bacterial proteins
What lies in the middle of the cytoplasm of bacterium cells?
A singular, circular chromosome made of DNA
What is considered to be additional DNA found in the cytoplasm of bacteria?
Plasmids
What is the function of plasmids?
They contain genes that give bacteria resistance against antibiotics
Are bacteria prokaryotic?
Yes
What allows for bacteria to rapidly exchange materials with their environment?
Their large surface area relative to their volume
Where can a slime capsule be found around bacteria?
Around parasitic bacteria when they are inside the host
For optimum growth what do bacteria require?
Moisture, a suitable temperature, a slightly acidic/alkaline environment and in some cases oxygen
What variety of nutritional types do bacteria display?
Photosynthesis,saprophytic,parasitic forms
Where do most bacteria live?
In or on their food
What do bacteria produce and releases which digests their food extracellularly?
Enzymes
What are aerobic bacteria?
Bacteria that need oxygen for their respiration
How can bacteria reproduce?
Multiplying by dividing in a process called binary fission
How does one bacterium pass resistance genes to another?
By giving them a useful plasmid
Do some bacteria need oxygen for their respiration?
Yes
Can other bacteria be anaerobic or aerobic depending on whether oxygen is available?
Yes
What are endospores?
A light but thick walled structure formed within the bacterial cell which contains the bacterium DNA
How many groups can we classify bacteria into?
16
What do we bases the classifications of bacteria into?
Their shape, ability to move and their metabolism
What are the four main types of bacteria?
Cocci
Bacilli
Spirilla
Vibrio
