Unit 5 - Energy transfers between organisms Flashcards
What do plants need energy for?
- Photosynthesis
- Active transplant
- DNA replication
- Cell division
- Protein synthesis
What do animals need energy for?
- Muscle contraction
- Maintenance of body temperature
- Active transport
- DNA replication
- Cell division
- Protein synthesis
Equation for photosynthesis
6CO2 + 6H2O + Energy –> C6H12O6 + 6O2
Aerobic respiration
Anaerobic respiration
- Aerobic - respiration using oxygen
- Anaerobic - respiration without oxygen
Equation for aerobic respiration
C6H12O6 + 6O2 –> 6CO2 + 6H2O + Energy
Anaerobic respiration
Products in plants and animals
In plants and yeast - ethanol and carbon dioxide is produced and energy
In humans - Lactate is produced and energy
How is ATP synthesised
ATP is synthesised via a condenstation reaction between ADP and inorganic phosphate using energy.
The energy is stored as chemical energy in the phosphate bond.
The enzyme ATP synthase catalyses this reaction.
Properties of ATP that makes is a good energy source
1) ATP releases only a small, manageable amount of energy at a time so no energy is wasted as heat.
2) It is a small, soluble molecule so it can be easily transported around the cell
3) It is easy broken down so energy can be released instantaneously
4) It can be quickly re-made
5) It can make other molecules more reactive by transferring one of its phosphate groups to them
6) ATP can’t pass out of the cell, so the cell always has an immedicate supply of energy
What is metabloic pathway?
A series of small reactions controlled by enzymes
What is phosphorylation
Adding phosphate to a molecule
What is photophosphorylation
Adding phosphate to a molecule using light.
What is photolysis
The splitting of a molecule using light energy.
What is photoionisation
When light energy excites electrons in an ato or molecule, giving them more energy and causing them to be released. The release of electrons causes the atom or molecule to become a positively charged ion.
What is hydrolysis
The splitting of a molecule using water
What is decarboxylation
The removal of carbon dioxide from a molecule.
Biomass
The mass of living material which can be measured as mass of carbon or dry mass per unit area.
What is gross primary production
The amount of chemical energy made avaliable by a producer
What is net primary production
The amount of energy available for consumers in the plant’s biomass after plant respiratory losses
Nitrogen cycle
1- Nitrogen fixation- Bacteria in root nodules turn N2 gas into ammonia that go onto form ammonium ions
2-Nitrification- ammonium is steb by step converted into nitrate ions by nitrifying bacteria
3- Denitrification- Nitrates in the soil converted into N2 gas by denitrifying bacteria in anaerobic conditions
4- Ammonification- Saprobionts convert dead organisms into ammonia, going onto form ammonium ions- this also occurs with animal waste
Phosphorus cycle
1- Phosphate ions are released from rocks into the soil by weathering
2- Mychorhizae allow phosphate ions to be absorbed into plants roots
3- They are passed through the food chain by consumption and excretion
4- Waste products and dead material are broken down by saprobionts
5- The original weathering releases phosporus into bodies of water aswell- this is taken up the food chain and passed through
6- Guano is the fecal matter of birds which contains a high level of phosphorus
Eutrophication
- Mineral ions leached from the fertilised field stiumate the rapid growth of algae in ponds and rivers.
- Large amounts of algae block light from reaching plants below.
- Eventually plants die because they’re unable to photosynthesise enough.
- Bacteria feed on the dead plant matter. The increased numbers of bacteria reduec the oxygen concentration in the water by carrying out aerobic respiration.
- Fish and other aquatic organisms die because there isnt enough dissolved oxygen.
What does the stroma contain?
Enzymes, sugars and organic acids
Light dependent reaction steps
1) Photoionisation- electrons excited by light energy to higher energy state
2) The electron void which is left causes a water molecule to split (Photolysis)
3)The excited electrons move down the electron transport chain- using energy to actively transport H+ ions into the stroma
4) The electrons are hit again by light at a different photosystem causing them to reduce NADP
5) H+ ions move by facilitated diffusion- providing energy for ATP synthase to synthesise ATP
Calvin cycle
RuBP(5c) + Rubisco —-> 2GP(3c)
2GP+ 2NADPH + 2ATP—> 2triosephosphate(3c) + 2ADP + 2NADP
2 Triose phosphate + ATP —> RuBP + ADP
