Unit 1B Flashcards
Micro-organism
Very tiny organisms that can only be seen in detail with a microscope.
There are 4 types - bacteria, fungi, viruses and protists
Unicellular
A single celled organism
Properties of micro-organisms
Grow rapidly
Have simple nutrient requirements
Produce a wide range of useful products
Conditions for growing microbes
Food supply
Warmth
Water
Correct pH
Yeast
A single celled fungus used in brewing and baking.
Baking
Yeast feeds on sugar in the dough and produces carbon dioxide gas.
This gets trapped in the dough and causes it to rise.
Brewing
Yeast is used to ferment the sugar in hops and barley into alcohol and carbon dioxide (which makes the beer fizzy).
Wine making
Yeast is used to ferment the sugar in crushed grapes into alcohol.
Fermenter
Large container used to produce beer in commercial quantities, in carefully controlled condidtions.
Batch processing
All the ingredients are placed into the fermenter at the start of the process, and it is emptied out when ready.
Used to brew beer.
Making yoghurt
Yoghurt bacteria are added to sterilised milk that has been heat treated so that it contains no bacteria.
It is placed in an incubator to keep it warm.
The yoghurt bacteria feed on the lactose sugar in the milk and turn it to lactic acid.
The increased acidity thickens and sours the milk to make yoghurt.
Biofuel
A renewable fuel made from plant or animal waste by fermenting it using bacteria.
Can be used for transport, heating or generating electricity.
eg. bioethanol (corn starch), biodiesel (waste oil), biogas (manure or food waste).
Sewage treatment
The sewage is screened and allowed to settle to separate the liquid and solid sludge.
The sludge is stirred and aerated (air is bubbled through it) allowing bacteria to grow on it and break it down.
The liquid part is filtered through gravel containing bacteria which break down the fine sewage particles.
Treated water is returned to the river.
Bioremediation
Using micro-organisms to break down harmful waste into less harmful products.
eg. sewage treatment, using bacteria to break down nuclear waste and using fungi to break down nerve gas.
Photosynthesis
The process that green plants use to make food (sugars).
Chloroplasts
Tiny structures inside plant cells that contain chlorophyll.
Chlorophyll
The green pigment found inside chloroplasts that is used to capture light energy.
Captured light energy
Splits water into oxygen and hydrogen, and is converted to chemical energy.
Oxygen is released as a waste product.
Hydrogen combines with carbon dioxide to make sugar in an enzyme-controlled reaction.
Photosynthesis equation
carbon dioxide + water ——————> glucose + oxygen
Starch
Made by joining glucose molecules together using phosphorylase enzyme.
Used to store the products of photosynthesis.
Iodine
Used to test for starch. Turns blue-black if starch is present.
Variegated leaf
A leaf with green and white areas.
Only the green areas contain chlorophyll.
Limiting factor
A factor that limits the rate of photosynthesis when it is short supply.
There are 3 limiting factors : light intensity, temperature and carbon dioxide concentration.
Greenhouse/polytunnel
Allow conditions to be controlled to increase the rate of photosynthesis.
This makes the plants grow faster.
Light, carbon dioxide and temperature can be controlled and plants can be protected from the wind. Greenhouses are naturally warmer, as heat is trapped by the glass.
Pond plant experiment
Used to measure the rate of photosynthesis.
The oxygen released by the plant can be collected and measured to study the rate of photosynthesis in different conditions.
Respiration
The release of energy from food molecules (sugars) that were made by plants in photosynthesis.
Happens in all cells.
The energy is used for cell division (for growth and repair), building (synthesis) of large molecules, muscle contraction and transport of materials in cells.
Digestive system
Food is eaten and digested into small molecules in the digestive system.
Small molecules pass through the small intestine walls into the blood and are transported to cells.
Aerobic respiration
Molecules are fully broken down in the presence of oxygen, releasing lots of energy.
glucose + oxygen ————————–> carbon dioxide + water + energy
Anaerobic respiration (fermentation)
Molecules are partially broken down in the absence of oxygen, to release a little energy.
glucose ————————–> lactic acid + energy (animals - during vigorous exercise)
glucose —————————–> ethanol + carbon dioxide + energy (plants and yeast)
Limewater
Used to test for the presence of carbon dioxide.
Turns from clear to cloudy.
Germinating peas
Peas that have started to respire and grow.
They give off heat that can be measured with a thermometer.
Dead peas act as a control (comparison) - they don’t produce heat as they are not respiring.
Lactic acid
Produced as a result of the partial breakdown of sugar in animals, in the absence of oxygen (anaerobic respiration).
Produced during vigorous exercise eg. sprinting.
Recovery period
After vigorous exercise has stopped, oxygen is used to breakdown lactic acid.
Percentage change
Work out the difference between 2 numbers, divide by the 1st one, then multiply by 100
Enzymes and respiration
Respiration is an enzyme controlled reaction, so is temperature dependent.
It is slow at low temperatures, increases to an optimum temperature then decreases again as enzymes are damaged by heat.
Controversial procedures
People have different views as to whether certain advances in biology, such as genetic engineering are morally acceptable or not.
Embryonic stem cells
Embryos are made of a ball of cells called embryonic stem cells.
To use them for medical treatments, the embryo must be destroyed.
This is why their use is controversial.
Herbivore
An animal that eats plants to obtain food molecules.
