5th Form Flashcards
Advantages of greenhouses
consistent internal environment+additional co2 in air
Water vapour is kept inside so reduces water loss via transpiration
2 types of fertilisers
Organic (animal feces) vs inorganic (chemically formed compounds to produce a specific amount of a particular ion)
organic vs inorganic fertilisers pros and cons
Organic pros:
improves soil structure
greater range of minerals
cheaper
Cons:
bulkier so less practical
may contain pests
inorganic pros:
fast acting
easy to apply
cons
leads to eutrophication
How to replace lost nitrates in soil
Add legumes, which have nitrogen-fixing bacteria, so convert nitrogen gas into ammonium ions. When the soil is ploughed, the ammnium is released into the soil, which is then converted to nitrates by nitrifying bacteria.
examples of biological control agents
pheromones
ladybirds (natural predator)
introduce sterile males
pesticides pros vs cons
reduces pest population immidiatly
cons:
need to regularly apply
chemicals can concentrate up the food chain
pests can become resistant to the chemicals
biological control pros vs cons
only one inital cost
no effect on other animals in the food chain
cons:
not all population killed
takes time to reduce the pest numbers
anaerobic respiration in yeast word and chemical
glucose to ethanol + co2
C6H12O6 to 2C2H5OH + “Co2
hydrogen carbonate indicator for co2
orange to yellow
experiment for anaerobic respiration in yeast
- Dissolve sugar in previously boiled water
- Add yeast and stir
3.Add a layer of vegetable oil - Connect via a bung and gas delivery tube to a second boiling tube containing limewater
bacteria used to make yogurt
lactobactillus bulgaricus
key steps for making yogurt
- Equipment is sterilised
- Milk pasteurised by heating
- lactobactillus bulgaricus is added to the milk and left at 46c for 4 hours
why is lactobactillus good
produces latic acid which lowers the Ph and therefore coagulate the mixture, giing yogurt its texture
why must fish species be seperated in fish farming
interspecficic competition + predation
problems with too many fish in a farmed pond + solutio
intraspecifc competion
rapid pathogenous spread
solution:
add antibiotics or antifungals/chemicals
problems with fish farming
fish may escape and upset ecosystem
fish may introduce pathogens
fish waste/ excess food can cause eutrophication
leaching
when trees are cut down, water runs off the soil instead of being absorbed by the roots. This means
a) there is a loss of minerals in the soil as they dissolve with the water
b) eutrophication can occur
c) the nutrient rich layer of topsoil is eroded
cause and effect of sulphur dioxide
released from cars and factories. They react with water in the atmosphere to create dilute acids. Can decreae the Ph of rivers and lakes, resulting in enzmes in animals being unable to react, creating death of organism. Also increases the dissolution of metal ions in soil, poisoning fish
steps of eutrophication
excess nitrates are abosrbed by algae
algae multiplies rapidly, so plants underneath die
bacteria feeds on dead algae and respires
fish die from lack of oxygen
how does rna differ from DNA
- RNA is single stranded (vs double stranded)
- RNA has a sugar called ribose (deoxyribose)
- RNA has base Uracil while DNA has base thymine
gene
a lengh of DNA which codes for a protein
