Unit 5 - Energy transfers in and between organisms
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CONCISE A/A* A level Biology Unit 5 Energy transfers within and between organisms complete revision notes (new spec)
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Unit 5 - Energy transfers in and between organisms
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AQA
I have condensed the entire A Level Biology AQA Unit 5 energy transfers within and between organisms section into an easy to read, concise booklet for MUCH cheaper than the typical revision guides which are too long and often overwhelming. These notes make all of the hardest A level biology topics ...
Unit 5 - Energy transfers in and between organisms
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Energy transfers in and between organisms
The main source of energy for an ecosystem is sunlight
Producers:
• plants
• perform photosynthesis
• use light energy to build biological molecules
Consumers:
• animals
• can’t make their own biological molecules
• eat plants (primary consumers) or other animals (secondary/tertiary consumers) to
obtain biological molecules
Decomposers:
• bacteria and fungi
• perform saprobiotic decomposition
• release enzyme onto dead plants/animals/waste (organic matter) breaking them down to
obtain biological molecules
Why producers (plants) need biological molecules
- Glucose -> respiration
-> store as starch
-> make cellulose
- Amino acids -> make proteins e.g enzymes
- Fatty Acids and glycerol -> make triglycerides as energy stores and protection
-> make phospholipids for membranes
Why consumers (animals) need biological molecules
- Glucose -> respiration
-> store as glycogen
- Amino acids -> make proteins e.g enzymes
- Fatty Acids and glycerol -> make triglycerides as energy stores and protection
-> make phospholipids for membranes
Why decomposers (bacteria/fungi) need biological molecules
- Glucose -> respiration
- Amino acids -> make proteins e.g enzymes
- Fatty Acids and glycerol -> make phospholipids for membranes
How organisms carry energy
- main source = glucose
- stored as starch in plants
,- stored as glycogen in animals
- others: lipids/fats/triglycerides/proteins
, 1.2 Saprobionts, Detritivores and Factors Affecting Rate of
Decomposition
Determining Dry Biomass
- put biomass on mass balance
- dry the biomass -> low temp. incubator or oven
- remeasure the mass
- repeat drying + measuring until the mass remains constant
Biological Molecules in the dry mass of an animal:
- proteins (CHON)
- carbohydrates (CHON)
- nucleic acids e.g ATP, amino acids (CHONP)
- lipids (CHO)
Detritivores = animals that feed on dead, organic material
e.g flies, dung beetles, worms
- All multi-cellular
Saprobionts = organisms that digest their food externally (by secreting enzymes) then absorb the
nutrients
e.g bacteria, fungi, moulds
- Mostly uni-cellular, few multi-cellular
Organic = carbon based
Inorganic = no carbon
What happens to nutrients after being digested?
- into soil to be absorbed by producers (plants)
- cycle restarts
Mycorrhizae = the association between roots and fungi; often a branching network providing
essential nutrients for the growth of the fungi and acting as an extended root system for the plants
Mutualistic Symbiotic Relationship = a close ecological relationship between
individuals of 2 species in which both species benefit
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