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Define:
Metabolism
Involves the production and use of enery via synthesis and breakdown of molecules
Define:
Catabolism
Breakdown of molecules, usually releases energy
Define:
Anabolism
Systhesis of molecules, usually requires energy
Describe the process of cellular respiration using the concept of metabolism
Cells have a constant requirement for energy but only a small amount of energy can be stored --> continuous cellular respiration is necessary for cells to gain energy and survive.
Cellular respiration involves a series of metabolic reactions which convert biochemical energy into ATP
Describe the pathways which occur within a living cell, with reference to:
Stepwise reversible reactions
Is a chemical reaction involving consecutive reations
Describe the pathways which occur within a living cell, with reference to:
Energy conservation
Very little energy can be stored in the cell
Describe the pathways which occur within a living cell, with reference to:
Enzyme catalysis
energy production must be catalysed to meet the cells demands, expecially during physical activity. The enzymes increase energy production but must also be able to inhibit energy synthesis if not required
Explain the role of energy rich bonds and energy storage molecules in the cell with reference to ATP
The bond between phosphate molecules in ATP are energy rich.
When these bonds are broken, they provide energy for the cells to use
Locate on a diagram of a cell the metabolic sites for:
Glycolysis
Cytoplasm
Locate on a diagram of a cell the metabolic sites for:
The Krebs Cycle
Mitonchondria (inside the double matrix)
Locate on a diagram of a cell the metabolic sites for:
The electron transfer chain
Mitochondria (inner membrane
Describe carbohydrate metabolism in therms of:
Carbohydrates are a chain of saccarides joined by chemical bonds. The carbohydrate metabolism aims to release energy via the breakdown of the large molecule and use it to produce high energy phosphate bonds
Describe carbohydrate metabolism in therms of:
Glycolysis
  • Glucose enters the cell, and undergoes phosphorylation (using 2 ATP)
  • Glucose molecule splits into two (producing 4 ATP) small net amoun of energy gain +2ATP
  • End product of glycolysis is pyruvate
  • Glycolysis is an anaerobic pathway
Describe carbohydrate metabolism in therms of:
Krebs, citric acid, or TCA cycle
  • Pyruvate enteres the mitochondria if oxygen is available (aerobic pathway)
  • Pyruvate is converted into Acetyl CoA (irreversible reaction catalysed by pyruvate dehydrogenase)
  • Acetyl CoA enters the Krebs cycle -  a serious of 8 reactions produce: CO2 (waste produced, breathed out), ATP (only one produced directly by the krebs cycle), NADH, FADH2 (important co-enzymes which carry H+ ions)
Describe carbohydrate metabolism in therms of:
The electron transport chain
  • Co-enzymes transport H+ to the electron transport chain
  • electrons jump along chain, releasing energy which binds p to ADP, creating 90% of the ATP we need
Differentiate between anaerobic and aerobic metabolism on the basis of:
Substrates Used
Anaerobic - Glucose
Aerobic - Pyruvate, Acetyl CoA, NADH, FADH2
Differentiate between anaerobic and aerobic metabolism on the basis of:
The products
Anaerobic - 2 pyruvate, 2 ATP, 2NADH
Aerobic - CO2, ATP, NAD, FADH
Differentiate between anaerobic and aerobic metabolism on the basis of:
The energy yeild from matabolism through the pathway
Anaerobic - Little energy per glucose molecule (2ATP)
Aerobic - Much greater energy per glucose molecule (28ATP)
Explain how a lack of oxygen will affect each of the 3 phases of cell respiration
Without oxygen, only glycolysis can be used to produce energy. This system is anaerobic, therefore work in the absense of oxygen (only for a short period of time before the system gets fatigued)
Without oxygen, the Krebs cycle cannot work and therefore, there is only a limited amount of energy able to be produced, for a short time
Describe the aerobic breakdown of glucose in terms of:
Recycling of reducded NADH2
The coenzyme NADH must be recycled fo that the krebs cycle has a constant supply. It the enzyme is not available, energy production will cease
Describe the aerobic breakdown of glucose in terms of:
The metabolic products and their effects on enzyme regulation
if products are in excess, inhibition occurs
Describe the aerobic breakdown of glucose in terms of:
Energy input and output
The aerobic breakdown of glucose (C6H12O6) in glycolysis produced 6ATP molecules
Describe the conditions under which lipids are used as an energy source and explain how they are metabolised
  • Lipids function primarily as an energy reserve
  • They are easy to store, but more difficult to breakdown than glycose (much larger molecule)
  • Lipids are broken down in the presence of oxygen, during extended periods of activity and produce more ATP than glucose
Describe the role of lipids as energy reserves
Lipids can be easily stored in cells all over the body as they are insoluble in water - they are hard to beakdown
Describe the role of glycogen as a short term energy store and describe glycogen breakdown
Glycogen requires water for storage and is only effective as short term energy storage
Glycogen is stored in the form of glycose and can retuen to glucose form to undergo glycolysis
Describe protein catabolism in terms of hydrolysis of peptide bonds and the conversion of amino acids into other metabolic intermedates
Protein is only used as an energy source in extreme cases where carbohydrates and lipids are not available (starvation)
Proteins are more effectively used by the body to build proteins
Proteins have a carbon skeleton, their amino acids can be broken down into pyruvate, Acetyl CoA and Krebs Cycle intermediates.
These can then be metabolised to produce ATP in a similar fasion to carbohydrates
Explain the importance of glycose as a blood fuel
Glucose is an important blood fuel as it can deliver energy all over the body quickly, to all cells
Explain the role of glyconeogenesis in blood glucose concentration
Glyconeogenesis is the production of glucose from fats, proteins and lactate
Compare provision of energy for cells in terms of metabolism of carbohydrates, fats and proteins
Carbohydrates are very efficient at producing energy but have limited stores - short duration, high intensity
Fats are low intensity, long duration exercises - aerobic zone. Lipids have extense stores
Proteins are rarely used for energy. Only used when supplies of carbohydrates and lipids run out
Inter-relate carbohydrate, lipid and protein metabolism and glycolysis as inputs to the Krebs cycle and electron transport chain
Describe the contribution of aerobic and anaerobic metabolism to energy production under conditions of changing energy requirements and oxygen availability
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