BIOL_BCHM_111_21_Energy Order.pdf

Key theme: Life needs energy Energy is the capacity to do work What do we need energy for? How can we harness energy efficiently? How can we store energy efficiently? How do enzymes help metabolism? What do we need energy for? An organisms metabolism transforms matter & energy What do we need energy...

Key theme: Life needs energy Energy is the capacity to do work What do we need energy for? How can we harness energy efficiently? How can we store energy efficiently? How do enzymes help metabolism? What do we need energy for? An organisms metabolism transforms matter & energy What do we need energy for? The free energy change tells us whether something will happen spontaneously How can we harness energy efficiently? Metabolic pathways are linked series of chemical reactions happening inside a cell How can we harness energy efficiently? ATP powers cellular work by coupling exergonic reactions to endergonic reactions How can we harness energy efficiently? ATP powers cellular work by coupling exergonic reactions to endergonic reactions How do we store energy efficiently? What sort of features are required in a fuel molecule? They must contain lots of energy They must be easily stored in a compact manner They must be easily converted into a useful form when needed Most of the fuels that we think of are hydrocarbons How do we store energy efficiently? Lipids are the main energy store in our body Fat (adipose tissue) Protein (muscle) Glycogen (muscle) Glycogen (liver) Glucose (fluids) Total 15,000g 6,000 120 70 20 555,000kJ 102,000 1,920 1,120 320 660,360 How do we store energy efficiently? Why use lipids instead of carbohydrates (and why not protein?) Fats: 37 kJ/g Carbs: 16 kJ/g Protein: 17 kJ/g Alcohol: 27 kJ/g How do we store energy efficiently? Why do plants use starch and we use glycogen? Chloroplast Mitochondria Starch Glycogen granules 0.5 µm 1 µm Glycogen Amylose Amylopectin (a) Starch: a plant polysaccharide (b) Glycogen: an animal polysaccharide How do we store energy efficiently? Carbohydrates are stored as glycogen and transported as glucose How can we harness energy efficiently? What would different athletes use as fuel? How can we harness energy efficiently? What would different athletes use as fuel? Distance: 100m Time: > 10 seconds, WR 9.58 (Bolt) Fuel: muscle ATP, glycogen Produces: lactate Distance: 42km Time: 2-2.5 hours, WR 2:01.39 Fuel: glycogen, FA Produces: CO2 + heat Distance: 42km run, 4km swim, 180km bike Time: 8-10hours Fuel: glycogen, FA, amino acids Produces: CO2 + heat + urea Key theme: Life is ordered Living things require order, and the fundamental unit of life is the cell. Cells use membranes to maintain order. The cell membrane is a mosaic of lipids, carbohydrates, and proteins that work together as a selective barrier Proteins allow compounds to pass through the membrane, through passive or active transport. The cell: an organisms basic unit of structure and function The cell: an organisms basic unit of structure and function Eukaryotic cells have internal membranes that compartmentalise their functions The cell: an organisms basic unit of structure and function Many different molecules come together inside a cell Membrane barriers need to be selectively permeable Cellular membranes are fluid mosaics of lipids and proteins Membrane barriers need to be selectively permeable Cellular membranes are fluid mosaics of lipids and proteins Membrane barriers need to be selectively permeable Transport proteins allow polar molecules through the membrane Carbohydrates provide strength and signals Coronavirus COVID-19 Coronavirus COVID-19 Wash your hands with soap! Soap molecule