memorise Flashcards
How do bacteria reproduce?
Bacteria reproduce asexually, through a process called binary fission.
- DNA copies itself, splits into two and attaches itself the the cell membrane.
- The cell membrane grows and pinches together in the middle
- The cell membrane breaks in the centre, leaving two identical cells with a complete chromosome.
How do bacteria gain nutrients
Extracellular digestion involves enzymes being allowed out through the cell membrane and being secreted onto food molecules. The enzymes catalyse (break down) the food into molecules small enough to be absorbed into the bacterium.
Saprophytic bacteria feed off dead and decaying matter. Bacteria which are parasitic feed off living matter.
How do fungi gain nutrients
Extracellular digestion.
The hyphae release enzymes onto the food source. The enzymes break down the food into food molecules which are then absorbed by the hyphae. The glucose from this is used in respiration.
How do bacteria grow
Bacteria grow bigger by using nutrients gained through digestion of food and energy released through respiration. When cells reach about optimum size, they split into two.
How do fungi grow
Fungi grow bigger through the nutrients absorbed by extracellular digestion. As they get taller, sporangia appear and eventually, the sporangia will become so large that it bursts.
How do bacteria respire
All living things respire (breathe) in order to convert glucose into energy.
Aerobic bacteria use oxygen in their respiration process. Their reaction is:
C6H12O6 (glucose) + O2 (oxygen)→ 4H2O (Water) + 2CO2 (Carbon dioxide) + Energy
Anaerobic bacteria do not use oxygen in respiration thus are less efficient and produce ethanol as a product.
C6H12O6 (glucose)→ CH3CH2OH (Ethanol) + CO2 (Carbon dioxide) + Energy
How do fungi respire
Aerobic fungi use oxygen in their respiration process. Their reaction is:
C6H12O6 (glucose) + O2 (oxygen)→ H2O (Water) + CO2 (Carbon dioxide) + Energy
Anaerobic fungi do not use oxygen in respiration thus are less efficient and produce alcohol as a product.
C6H12O6 (glucose) → CH3CH2OH (Alcohol) + CO2 (Carbon dioxide) + Energy
[Yeast is an anaerobic fungi useful in baking].
How do bacteria excrete
Aerobic bacteria release carbon dioxide and water. Anaerobic bacteria release alcohol and carbon dioxide.
Most saprophytic bacteria excrete usable nutrients. Pathogenic bacteria excrete toxins (strong poisons) and also some glucose products.
How do fungi excrete
Saprophytic fungi digest dead plant and animal matter and release nutrients.
How do bacteria reproduce
Bacteria reproduce through binary fission.
- The single loop of chromosome duplicates and attaches to the cell membrane.
- The cell membrane then grows to double its original size.
- A thick cell wall grows between the two DNA molecules, which then split off into two identical cells.
How do fungi reproduce
Fungi can reproduce sexually or asexually.
1: A mature sporangium bursts, releasing many spores, which are carried away by the wind.
2: The spores land on a food source and grow hyphae - long, thin, branching cells.
3: After a few days of growth, sporangia grow from the hyphae and soon, they will release spores of their own, restarting the cycle.
How do viruses reproduce
Viruses cannot reproduce without the aid of another organism - they are obligate parasites. This means they must find a host cell, attach to it, and then inject their genetic material into the host cell.
Once inside, the DNA or RNA hijacks the cell processes, forcing it to produce the viruses’ nucleic acid and the containing capsule, which later assembles into fully functional viruses.
In the final stage, enzymes are released breaking down the cell wall of the host cell, releasing the newly produced viruses.
Can viruses be considered living? Why or why not?
The main function viruses perform is reproduction. They do not grow, feed, respire or excrete. zzzzz!!!!!!!!!!!!!!!!!
How does temperature affect the life-processes of microbes?
Bacterial growth rate doubles for every 10ºC rise in temp. Above a certain optimum temp, growth slows. Most bacteria are killed at higher temperatures, between 55-60ºC.
Enzymes involved in life processes of bacteria are slowed down by low temperatures
How does oxygen availability affect the life-processes of microbes?
affects respiration: Bacteria and fungi can respire with or without oxygen - most will use aerobic respiration if O2 is available, as it is much more efficient.
Some organisms require there to be no oxygen present for respiration to occur - this is anaerobic respiration. It is less efficient, but can be carried out almost anywhere.
