What are the conditions of life?
Movement
Respiration
Sensitivity
Control internal conditions
Reproduction
Nutrition
Growth
What are plants?
- have chloroplasts and cellulose cell walls
* store carbs as starch or sucrose
What are animals?
- no chloroplasts/cell walls/PS
- usually have nervous coordination
- can move from one place to another
- often store carbs as glycogen
What are fungi?
- no PS
- body as mycelium w thread like structures for many hyphae. These have many nuclei
- some single celled
- cell walls of chitin
- fed by extra cellular secretion of digestive enzymes onto food material and absorption of organic products (saprotrophic nutrition)
What are bacteria?
- single celled
- cell wall, membrane, cytoplasm and plasmids, but no nucleus. Instead circular chromosomes of RNA
- some carry PS but most feed off other organisms
What are protoctists?
- single celled
* some, like amoeba have animal cell features but other like chlorella have features like plant cells
What are viruses?
- smaller than bacteria
- parasitic, can only reproduce inside other things
- no cellular structure, but have a protein coat and DNA or RNA
What is a pathogen?
Microbes that can cause disease. Can be fungi, protoctists, bacteria or viruses
How does blood clotting work?
- need to speak wound quickly to avoid blood loss and stop pathogens entering
- ∴ when a blood vessel breaks platelets (small cells in blood) stick together and activate formation of a mesh of proteins called fibrin
- more platelets and RBCs get caught ∴ scab scab is formed to seal cut
What defences does the body have against pathogens?
Respiratory system: Mucus, ciliates epithelial cells Eyes: Enzymes in tears Skin: Waterproof, impermeable Nose: Nasal hair, mucus, sneezing Mouth: Salivary enzymes, coughing reflex Stomach: acid Vagina: acidic secretions
What are phagocytes?
- WBCs that engulf pathogens
- easily pass through cell walls and move towards pathogens, then engulf them, and release enzymes to digest and destroy it
- this is called phagocytosis
What are lymphocytes?
- WBCs that make antibodies/antitoxins
- antigens are substances on the surface of a pathogen- different pathogens have different ones
- antibodies are proteins that can recognise and bind to antigens- different lymphos make ones specific to a particular antigen
- when lymphos meet pathogens w AGs they know they divide quickly and make many ABS to bind, which destroys the pathogen and can help phagos to to engulf and digest pathogen more easily
- bacteria release toxins to makes us ill ∴ ATs made by lymphosto neutralise actions of toxins
How does vaccination work?
• vaccines contain dead or less infectious versions of AGs
• trigger lymphocyte activation- antibody production and formation off memory cells
∴ in future antibody production will happen sooner, faster and in great quantity as mem cells exist
How do antibiotics work?
- destroy cell wall, e.g.g penicillin
* or stop protein synthesis ∴ no genere replication ∴ no cell division, e.g. Tetracycline
How does antibiotic resistance happen?
- Severe infection
- Antibiotics stopped
- Immune system can’t cope w all the pathogens. They multiply
- Many resistant bacteria
- Even w antibiotics immune system can’t stop due to all resistant bacteria
- Infection not cleared
How do we use Microorganisms to create beer?
• yeast anaerobically respires (fermentation) to make ethanol
Glucose ⇒ CO2 + alcohol + some energy
How do we use Microorganisms to create yoghurt?
• anaerobic respiration of lactobacillus
Lactose ➯ lactic acid
• lactic acid lowers pH meaning harmful pathogens can’t enter
• also makes milk clot and denatures the milk enzymes to give it its sharp taste
1. Milk pasteurised to kill bacteria, roughly 85°C
2. Milk is homogenised
3. Milk is cooled and incubated w lactobacillus
4. Milk incubated for several hours
5. Fruit/flavours added
What is an investigation to measure CO2 production by yeast?
Get two test tubes, with a bung and a tube leading from on to the other. Place yeast and sugar solution in the one with the bung, and limewater or hydrogen carbonate indicator (orange to yellow in CO2 in the other). This will change if the yeast respires and produces CO2. Repeat, but with a layer of liquid paraffin covering the yeast and sugar solution to get anaerobic respiration.
What is the point of the steam inlet in a fermenter?
Hot steam sterilises the inside of the fermenter- this is for aseptic conditions to prevent contamination by unwanted Microorganisms
What is the point of the nutrient inept in a fermenter?
Allows sterile nutrias to enter fermenter- microbes need it to grow and reproduce
What is the point of the water jacket with cooling water in a fermenter?
Keeps temp inside constant ∵ Microorganisms for best at an optimum temp
What is the point of the air inlet in a fermenter?
Provides a source of oxygen, as Microorganisms need it for aerobic resp
What is the point of the filter on air inlet in a fermenter?
Stops Microorganisms getting in fermenter ∴ prevents contamination
What is the point of the stirring paddles in a fermenter?
Keeps the mixture in the fermenter agitated ∴ mixes Microorganisms w nutrients and keep temp even
