Biology - 90927 - 1.3 Flashcards
What are bacteria, fungi (yeasts and moulds), and viruses? (micro-…)
Micro-organisms
Order in size of the following cells: mould, yeast, virus, bacteria (rod), bacteria (coccus), animal cell, animal nucleaus
Virus (0.1μm), bacteria (coccus) 1μm), bacteria (rod) (2-3μm), animal nucleus (2.8μm), yeast (5-8μm), animal cell (10μm), mould (often >40μm).
Are bacteria aerobic or anaerobic?
Bacteria may be either
Are bacteria single-celled organisms?
Yes
What do bacteria need to survive?
Food, moisture, warmth.
Bacteria reproduce by?
Binary fission
At what speed can bacteria reproduce in good conditions?
Every 20 mins
Saprotrophic/saprophytic bacteria
Decomposers that feed on dead organisms and wastes (urine and faeces)
Pathogenic bacteria
Parasites that feed on a living host, causing a disease.
Yeast, mould and mushrooms are all
Fungi
What do fungi need to survive?
Warmth, moisture, food
Are fungi aerobic or anaerobic?
Fungi may be either
Hyphae
Fine thread-like structures that spread through the substance that the fungus is living on.
Spores
Asexual reproductive ‘seeds’ that burst out of mature sporangia, settle, and grow
Saprotrophic/saprophytic fungi
Decomposers that feed on dead organisms and wastes (urine and faeces)
Pathogenic fungi
Parasites that feed on a living host, causing a disease.
What do viruses need to survive?
A living host
Are viruses living?
No, they do not grow, feed, respire, or excrete wastes. They do reproduce
How do viruses reproduce?
Enter a living cell (host) and make copies of themselves.
By what process to fungi and bacteria feed?
Extracellular digestion
Extracellular digestion
Enzymes released by hypae, food digested, nutrients absorbed.
How many bacterial cells are in a colony that can be seen by the naked eye?
At least 1 million
How can viruses be cultured?
Using living cells as hosts
Saprotrophs idead temp?
30 degrees. Range 5-45 degrees.
Do campylocacter and Helicobacter pylori require high or low amounts of oxygen
Low (they can survive in the human digestive system)
Aerobic respiration equation
Glucose + oxygen -> carbon dioxide + water + ATP
Anaerobic respiration for lactic acid bacteria
Glucose -> lactic acid + 2ATP
How does yeast respire anaerobically?
Fermentation
Anaerobic respiration equation for yeast
Glucose -> ethanol + carbon dioxide + 2ATP
Do all living cells need water?
Yes
Ideal pH for micro-organisms?
6-8
Which type of micro-organism can handle lower pH
Lactic acid bacteria
Can the toxins produced by micro-organisms kill the micro-organisms?
Yes
Do micro-organisms compete with each other?
Yes
What micro-organisms require a host cell to live and grow?
Viruses and pathogenic bacteria and fungi
Do micro-organisms break down dead plants and animals?
Yes
What does composting do?
Micro-organisms decompose dead plant material, creating nutrient-rich compost, favourable for plant growth.
How does bread rise?
Yeast combined with sugar causes fermentation, breaking down the sugar to produce carbon dioxide. The CO2 causes the rise.
What 2 common food products are produced using lactic acid bacteria?
Cheese and yoghurt
What 4 main steps does cheese making involve?
Acidification, coagulation, dehydration, salting.
pH of yoghurt?
4
Aerobic and anaerobic bacteria feed on which parts of sewage?
Aerobic = liquid sewage. Anaerobic = solid sewage.
How is penicillin made?
Fermentation of the mould, Penicillium, or synthetically.
Epidemiology
Study of patterns of disease
Food poisoning
Any illness caused by eating food contaminated by bacteria or their toxins.
Common bacteria causing food poisoning
Campylobacter, Salmonella, E. coli, Staphylococcus aureus, Listeria, Clostridium botulinum
Poisoning from Campylobacter and Salmonella usually caused by?
Undercooked chicken
What are most plant diseases caused by?
Fungi
Dying plant parts and brown spots could indicate…
Grey mould (fungi) infection
What bacteria attacks the leaves of Golden Kiwifruit?
Psa
Why do pathogenic micro-organisms cause a range of diseases in humans?
Warm, moist bodies provide excellent conditions for growth and reproduction (each pathogen has it’s own environmental requirements)
Can bacteria, and spores from bacteria and fungi grow on objects that are made from plant and animal materials (e.g wood, cotton, leather, wool)? How do the micro-organisms feed?
Yes. Feed by extracellular digestion.
Why is unnecessary prescribing of antibiotics bad?
Encourages the development of resistant bacteria.