CORE ONE: MAINTAINING A BALANCE
IDENTIFY THE ROLE OF ENZYMES IN METABOLISM, DESCRIBE THEIR CHEMICAL COMPOSITION AND USE A SIMPLE MODEL TO DEMOSTRATE THEIR SPECIFITY ON SUBSTRATES. Enzymes are biological catalysts this means that they lower the energy required to start a chemical reaction within a cell but don’t get used up by that reaction. Every reaction and process in the metabolism of the cell is controlled by a specific enzyme. Enzymes are globular proteins whose shapes are specialised so that substrates can form a temporary bond with them. The model that best describes that is the “lock and key”. This is where only one part of the enzyme molecule can form a complex with the substrate. This part is called the active site. •
IDENTIFY THE pH AS A WAY OF DESCRIBING THE ACIDITY OF A SUBSTRATE PH is a scale related to the concentration of hydrogen ions in a solution. PH value of 0-6 indicates an acidic solution. 7PH indicates a neutral solution and 8 – 14 is an alkaline solution.
EXPLAIN WHY THE MAINTENANCE OF A CONSTANT INTERVAL ENVIRONMENT IS IMPORTANT FOR OPTIMUM METABOLIC EFFIENCY Enzymes control all metabolic reactions and processes in the body. Enzymes work optimally in an environment where the optimum temperature and PH conditions are met. At temperatures and PH other than the optimum, the enzymes fail to work as efficient as they should, or not at all.
DESCRIBE HOMEOSTATIS AS THE PROCESS BY WHICH ORGANISMS MAINTAIN A RELATIVELY STABLE INTERNAL ENVIRONMENT. Homeostasis is the process by which the internal environment is kept within normal limits regardless of the external environmental conditions. This includes things such as Temperature, PH, Gas Levels, Water and Salt concentration. This allows the enzyme optimum to be met and the body to work efficiently and to be kept stable.
EXPLAIN THAT HOMEOSTASIS CONSISTS OF TWO STAGES – DETECTING CHANGES FROM STABLE STATE AND – COUNTER REACTING CHANGES FROM STABLE STATE. A receptor detects a change in some variable organisms’ internal environment, for example a sensory neuron pick up a decrease in the temperatures surrounding the body. An appropriate response occurs that counter reacts the changes and thus maintains a stable state, for example shivering to generate heat in the muscles. •
OUTLINE THE ROLD OF THE NERVOUS SYSTEM IN DETECTING AND RESPONDING TO ENVIRONMENTAL CHANGES. Nervous system consists of the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS consists of the brain and spinal cord. The PNS consists of the sensory nerves. When the environmental temperature begins to exceed comfortable levels for the body, the temperature sensors in the skin detect the change in the sensory neuron which conducts a nervous impulse to the brain. Nerve impulses pass this information to the blood vessels, sweat glands, endocrine glands and muscles. •
IDENTIFY THE BROAD RANGE OF TEMPERTURES OVER WHICH LIFE IS FOUND COMPARED TO NARROW LIMITS FOR INDIVIDUAL SPECIES. Species can be found at extremes ranging from -40C to + 120C. However the majority of living organisms are found in -2C to 40C range for each individuals species is even narrower. Below 0C cells risk ice crystals forming in them and about 45C proteins within cells could denature.
COMPARE RESPONSES OF NAMED AUSTRALIANS ECTOTHERMIC AND ENDOTHERMIC ORGANISMS TO CHANGES IN THE AMBIENT TEMPERTURE AND EXPLAIN HOW THESE RESPONSES ASSIST IN TEMPERATURE REGULATION. ENDOTHERMS- In hot conditions, the kangaroo licks its paws, where the skin is thinner and blood supply is closer to the surface, so that heat can be easily released. Evaporation from saliva promotes the loss of heat from the blood. ECTOTHERMS- Magnetic termites pack the walls of their mounds by insulating wood pulp and align their mounds North to South to maximize exposure to the sun in mornings and evenings. When the air is cooler and it minimizes the heat in the middle of the day. ECTOTHERM- Antarctic ice fish...
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