Metabolism consists of two types of reactions: Anabolic (Build up of smaller molecules into larger ones) and Catabolic (Break down of larger molecules into smaller ones) Enzymes are proteins. They are a polypeptide chain of amino acids which are heavily folded to form a three dimensional shape. Within this structure is an active site, typically composed of 3-4 amino acids which are areas that substrates will bind to and catalyst chemical reactions. There are two theories to describe enzyme action and specificity.
The original theory, the lock and key theory explains enzyme action by likening it to a lock and key where only a specific substrate will unlock a specific active site. The current theory – the induced fit theory assumes that the substrate plays a role in determining the final shape of the enzyme substrate complex and the active site is more flexible. The substrate enters and binds to the enzyme to shape the active site to properly align the complex for a reaction to take place. 1. Identify pH as a way of describing the acidity of a substrate pH is a measure of the acidity of a substance. It is measured on a scale from 0-14. * pH of 7 is neutral * pH under 7 is acidic * pH over 7 is alkaline/basic Enzymes usually function best at a specific temperature and pH range. If these are o extreme the enzyme will denature. Homeostasis 1. 3 Explain why the maintenance of a constant internal environment is important for optimal metabolic efficiency Homeostasis is the maintenance of a constant internal environment.
This is important tort optimal metabolic efficiency because enzymes are required tort this. Enzymes have specific conditions under which they can operate at an optimal level. Outside these conditions, their activity decreases and may become denatured. Therefore, it is vital for homeostasis to occur so that enzymes can maintain their optimal level of activity and hence, optimal metabolic efficiency 1. Describe homeostasis as the process by which organisms maintain a relatively stable internal environment Homeostasis is the maintenance of a constant internal environment.
If a condition within the body changes such as rise in body temperature, the process of homeostasis ensures that mechanisms within the body detect this change and counteract it so that the body temperature remains at ICC 1. 5 Explain that homeostasis consists of two stages * Detecting changes from the stable state * Counteracting changes from the stable state Homeostasis mechanisms consist of two stages: Changes from the stable state are detected by organs called receptors. E. G. Skin detects lack of heat (cold) * Changes are counteracted using effectors organs. E. G.
Skin produces goose bumps This is known as negative feedback system where the reaction brings about a counteraction to the stimulus. This creates a constant internal environment regardless of external environment. In between the stages of detection and counteraction, the brain and spinal cord (Central Nervous System – CANS) will coordinator the response to the change. 1. 6 Outline the role of the nervous system in detecting and respond to environmental changes The nervous system enables the detection of changes to the body and coordinates the responses to counteract these changes.
It consists of two interaction elements – Central and Peripheral nervous system (CANS and PANS) The CANS is composed of the brain and spinal cord. The spinal cord transmits messages from the receptor organs to special regions of the brain such as the hypothalamus. The hypothalamus receives stimuli from sensory neurons and then coordinates the correct response to counteract the change but sending our messages to effectors organs via motor neurons. The hypothalamus also controls the release of ermines that produce changes in the body. The PANS is composed of all the neurons outside the CANS.
These include sensory and motor neurons. Sensory neurons transmit messages from the receptor organs to the CANS. Motor neurons transmit messages from the CANS to the effectors neurons which conduct the change. 1. 7 Identify the broad range of temperatures over which life is found compared with the narrow limits for individual species Climatic temperatures on Earth can vary from -ICC to ICC. Most animals and plants cannot tolerate this extreme range and hence reside in habit tats that do not vary significantly. Most mammals generally survive between 0-ICC.
Reptiles have a narrower range because their body temperature is the ambient. 1. 8 Compare responses of named Australian exothermic and endothermic organisms to changes in the ambient temperature and explain how these responses assist temperature regulation Reptile: Diamond Python Diamond Python I Physiological I Structural I Behavioral I Cold conditions -Lies on eggs and shivers to increase the temperature of incubation I -Dark in color to absorb heat and can therefore tolerate colder temperatures than most snakes I -Basks in the sun to raise body temperature.
Hibernation-Migration to warmer areas I Warm conditions I I -Is nocturnal – hunting at night to escape heat of the day-Burrowing during the day I Mammal: Red Kangaroo Red Kangaroo I Physiological I Structural Behavioral I Cold conditions I -Increased metabolic rate to create more heat within the body I I Basking in the sun I Warm conditions I -Decrease in metabolic rate I -Panting to release heat-Exposed areas of skin on the forelegs to increase evaporative cooling of the blood from this area-shunting of the blood from the tail to exposed areas of the skin on the forelegs to increase heat loss I -Nocturnal-Licking forelegs to increase evaporation-Sitting in the shade | 1. 9 Identify some responses of plants to temperate change Plants are exothermic and are not above to maintain a constant temperature. Therefore they have a range of adaptations that enable survival in a variety of temperatures. These adaptations include: * Leaf fall To reduce surface area exposed to sun, leaves will drop their leaves. This reduces the effect of transpiration. * Radiation Some plants have shiny leaves which reflect solar radiation. Heat-shock proteins Heat-shock proteins are produced by plants when under stress from high temperatures. These stop denaturing of the enzymes so that normal cell reactions can continue * Transpiration The movement of water up the plant from the roots to the leaves via transpiration stream serves to cool the plant. The evaporation of water from the stomata of the leaves also serves to cool the plant Shoots and leaves of a plant may die but left in the soil are bulbs, roots or rhizomes that will begin to grow again when favorable conditions return * Orientation of leaves Eucalyptus leaves are characterized by drooping towards the ground during hot days. This reduces amount of light rays that are in contact with leaf, reducing amount f heat. Seed Dispersal Some plants rely on extremely high temperate such as those produced by fire to germinate their seeds. * Overvaluations Overvaluations is the process whereby plants must be exposed to cold conditions for them to produce flowers and therefore, reproduce. Maintaining Nutrients 2. 1 Identify the form(s) in which each of the following is carried in mammalian blood: Carbon dioxide, oxygen, water, salts, lipids, nitrogenous waste and other products of digestion. Blood has a critical role in the transportation of substances that are essential to life, such as oxygen, water and glucose throughout the entire body. It also removes waste products from cells that are poisonous in bulk.
These substances include: Substance I What it is carried by I Form it is carried in I Oxygen I Red Blood cells I Oxygenation (02 + Hemoglobin) I Carbon dioxide I Plastered blood cells I * Mostly as bicarbonate ions * Cerebrate (CA + Hemoglobin)Some dissolved in plasma I Water I Plasma I Water molecules I Salts I Plasma I Ions Lipids I Plasma I Chlorine ( Package of digested lipids, phosphoric and cholesterol wrapped in protein) I Nitrogenous wastes I Plasma I Mostly urea I Other products of digestion I Plasma I Whole molecules: For example – loose I 2. 2 Explain the adaptive advantage of hemoglobin Hemoglobin is an adaptive advantage to organisms because it allows for more oxygen to be supplied through the blood. Hemoglobin works effectively as a carrier molecule because it contains iron, an element that easily combines with oxygen.
Human red blood cells contain no nuclei so that they can carry as many hemoglobin molecules as possible. The structure of red blood cells and structure of hemoglobin maximize the amount of oxygen that can be carried in the blood. 2. 3 Compare the structure of the arteries, capillaries and veins in relation to their function Arteries Arteries travel away from the heart to the furthest reaches of the body. To do this, it must be pumped under high pressure resulting in thick muscular walls to cope with the pressure. Artery walls are also quite elastic, enabling them to expand and contract to adjust to the amount of blood traveling through them at any given time. The main artery leaving the heart is called the aorta.
The aorta’s role is to carry oxygenated blood at pressure away from the heart to the tissue of the body. A second main artery leaving the heart is the pulmonary artery (pulmonary = lungs). This carries degenerated blood to the lungs. Arteries are composed of three layers: An outer layer of connective tissue with elastic fibers, a middle layer of muscular tissue also with elastic fibers and an inner layer of epithelial cells. The outer layer is tough to protect the artery and made up of connective tissue which allows it to stretch. The middle layer is muscular to allow for strength and flexibility and the inner layer is smooth to allow easy blood flow.
Veins Blood coming into the heart moves through the veins. Degenerated blood from the body enters the heart via a sell called the even cave, while oxygenated blood from the nuns enter the heart via the pulmonary vein. Bloody returning from the blood does not have as much ‘push’, causing it to be under lower pressure. This results in thinner walls, wider diameters and special devices called valves to prevent the blood from flowing backwards. The movement of blood through the veins is aided by contraction of the muscles running alongside veins. Capillaries Capillaries are the smallest of the blood vessels. They are made up of endothelial – a single layer of flat, overlapping cells.
The diameter is Just wide enough for a slow, single file of red blood cells to pass through. This maximizes opportunity for the exchange of gases, nutrients and wastes between the blood cells and the tissue cells. 2. 4 Describe the main changes in the chemical composition of blood as it moves around the body and identify tissues in which these changes occur 2. 5 Outline the need for oxygen in living cells and explain why the removal of carbon dioxide from cells is essential Cells must have their own supply of oxygen. This is because oxygen is an essential reactant in aerobic cellular respiration which produces usable energy in the form of TAP. Aerobic cellular respiration
Oxygen + Glucose TAP + Carbon Dioxide + Water The process of producing energy requires energy and produces carbon dioxide as a waste product. The accumulation of carbon dioxide in cells results in the lowering of the pH and hence causing an acidic environment. This prevents optimal enzyme activity as well as the possibility of denaturing. 2. 6 Describe current theories about processes responsible for the movement of materials through pants in xylem and phloem tissue Xylem – Water and mineral ions Xylem is the tissue that carries water and dissolved mineral ions (such as nitrates) through a plant. Water enters a plant through its roots, mostly via the root hairs.
O reach the xylem tissue, water forges a pathway between neighboring cell wars or move through the cell walls, either directly or through channels inside the walls. The process though to initiate the movement of water in the xylem of a plant is transpiration. Water lost through the stomata is replaced from the fluids in nearby cells, creating a concentration gradient that draws water by osmosis from the xylem. This ‘pulling effect’ begins at the top of the plant and acts on wall the water below, creating a transpiration stream that relies on passive transport Acting in tandem with the transpiration stream is capillarity – capillary forces. These include cohesion and adhesion forces. This is believed to help ‘pull’ the water up the fine xylem tubes that run through the plant.
Root pressure plays a minor role in the transport of water through the xylem. Internal fluid pressure in roots causes water to be pushed up the stem. Phloem – Nutrients such as carbohydrates, amino acids and hormones Much of the movement of substances in the phloem occurs from the regions of the plant where materials are manufactured to regions of the plant where these materials are used for growth or storage. Different substances move through the sieve tubes of the phloem at different rates. The movement of materials from the leaf to the phloem and from the phloem to where it is needed requires energy and is hence regarded as active transport. Movement of nutrients along the phloem is by passive transport.
In an action referred to as source to sink, sugar and other organic materials manufactured by photosynthesis are believed to move into the phloem by active transport at the leaves (source) then to parts of the plant where they are used and stored (sink). The most widely accepted explanation for this movement is the erasure flow theory. The movement of sugar from leaf cells into the phloem results in a high concentration of solutes in the phloem, which causes water to enter by osmosis. This creates a region tot nigh pressure in that section tot the phloem tube and because of this, sugar is forced from cell to cell away from the source along the phloem. The building up of pressure at the source and reduction of pressure of the sink creates a pressure gradient that insures a constant substance flow. Managing gases, water and wastes 3. Explain why the concentration of water in cells should be maintained within a arrow range for optimal function An adequate supply of water for cells is necessary for several reasons: * Water is the medium that transports and distributes many substances in and between cells (such as nutrients and wastes) * It is the solvent in which many important ions and molecules required for metabolic reactions are dissolved. Such substances are only able to move to where they are needed because they are in a solution and hence, can diffuse across cells. The optimal functioning of cells is reliant on their water content being kept within a very narrow range. The concentration of water inside cells should be isotonic with the fluid outside the cell. If the cell is not isotonic then it leaves it vulnerable to losing or gaining too much water. The regulation of water concentration is required to maintain homeostasis – known as congratulations 3. Explain why the removal of wastes is essential for continued metabolic activity Cells are the site of many metabolic reactions which produce wastes that, if left to accumulate, would poison and eventually kill the cell. Wastes, in particular nitrogenous wastes (by-products of the breakdown of proteins) just be excreted quickly because they have the ability to harm enzymes and slow down chemical reactions, change pH and interfere with the transport of substances across cell membranes. 3. 3 Identify the role of the kidney in the excretory system of fish and mammals The kidney is the main organ involved in congratulations and extraction of wastes in mammals. The kidney filters the blood of metabolic waste products such as urea and maintains a stable concentration of water in the blood stream.
Mammals have 2 kidneys located on either side of the abdomen. They are connected to the renal artery and renal vein. The renal artery carries blood from the heart to the kidney and the renal vein carries blood from the kidney to the heart. The router is the tube that Joins the kidney to the bladder. The urethra carries urine, filtered by the kidney out of the blood, from the kidney to the bladder where it is stored until release. 3. 4 Explain why the processes of diffusion and osmosis are inadequate in removing dissolve nitrogenous wastes in some organisms Multicultural organisms are too large to rely on the processes of diffusion and osmosis to excrete their nitrogenous wastes.
These wastes cannot simply diffuse cross a single-celled membrane to leave an organism. Therefore, complex systems and organs are formed to perform this function. The kidney is developed for the purpose of waste removal through active transport. 3. 5 Distinguish between active and passive transport and relate these to the processes occurring in the mammalian kidney Passive transport is the movement of substances along the concentration gradient. This requires no energy. This type of transport occurs in the kidney in the neoprene at the: * Proximal convoluted tube – K+, water * Loop of Henley – Water * Collecting duct – Water Active transport is the movement of substances against the concentration gradient. This requires energy.
This type of transport occurs in the kidney in the neoprene at the: * Proximal convoluted tube – Nasal, Glucose, H+, Ammonia, drugs (I. E aspirin) * Loop of Henley – Nasal * Distal convoluted tube – K+, H+, Ammonia, drugs, An+, HCI 3. 6 Explain how the processes of filtration and reapportion in the mammalian neoprene regulate body fluid composition Filtration Filtration occurs in the slumberous. Blood is carried to the slumberous via the renal artery. It is made up of a dense bed of tightly packed capillaries. The pressure from this pack causes plasma to be filtered out of the blood and into the Bowman’s capsule. This globular filtrate is made up of such substances such as water, sodium, chloride, glucose, urea, amino acids, and other substances dissolved in plasma.
Orb’s, Web’s, large proteins (I. E hormones) cannot fit through the capillary walls. The Bowman capsule collects the globular filtrate where it passes onto the kidney tubules. This process is passive and is determined by the size of the particles. Reapportion Some substances in the globular filtrate are needed for the body such as glucose ND salts. These substances are reabsorbed back into the bloodstream in the kidney tubules (Proximal convoluted tubule, Loop on Henley and Distal convoluted tubule). A combination of active and passive transport is used for reapportion. The kidney uses both active and passive forms of diffusion in the process of urine titration.
Osmosis trot the kidney tubules back into the b takes place to maintain the concentration of water in the blood. The kidney uses active transport of ions because passive transport is too slow to ensure all the wastes are removed in a timely manner. 3. Outline the role of the hormones, lodestone and DAD (anti-diuretic hormone) in the regulation of water and salt levels in blood DAD (anti-diuretic hormone/ visionaries) and lodestone are the main hormones involved in congratulations. DAD(Anti-diuretic hormone/ Visionaries) When the body is low on water, special receptors in the hypothalamus detect this as a rise in the concentration of solutes in the blood.
IN response, the brain releases DAD which increases amount of water reabsorbed and a decrease in the volume of urine produced. The absorbed water is returned to the blood and solute concentration falls. Lodestone Lodestone is produced by the adrenal glands. When water levels fall, concentration of solutes in the blood rises and this change is detected by receptors in the brain. Low water in blood causes drop in blood pressure simply because a reduced volume of blood. This causes more sodium to be absorbed through the globular filter and more water enters the blood. This is a result of lodestone which causes the neoprene walls to be more permeable. 3. Define instantiations as the maintenance of metabolic and physiological functions in response to variations in the environment and discussions its importance to estuarine organisms in maintaining appropriate salt concentrations Estuarine-dwelling organisms such as crabs, oysters and mangroves must cope with constantly changing salt levels due to changing tidal movements in a transitional habitat between salt and fresh water. Instantiations is the term given to the function of coping with this change in salinity. Instantiations uses metabolic and physiological functions to maintain constant internal salinity, similarly to homeostasis but with salt. Organisms that can tolerate changing levels of salinity are called realizing. Realizing organisms employ various tactics to undergo instantiations and to cope with the changing salinity.
There are two main types of Realizing organisms: * Somersaults * Commemorators Somersaults are organisms which use special physiological mechanisms that allow them to control salt levels in their bodies. An example of this is the mangroves, which cope with salinity levels by accumulating excess salt in bark and leaves which are shed or removed from the tree later. In other words, salt is essentially sent to an internal ‘rubbish bin’ (The bark and leaves). Commemorators lack physiological adaptations to control salt levels and hence, use behavioral mechanisms to control salt levels. An example of this is the bivalves (shells) which shut tightly in order to lock out salty water. Blueprint of Life Evolution 1. Outline the impact on the evolution of plants and animals of: physical conditions in the Environment * Changes in chemical conditions in the environment * Competition for resources * Changes in Evolution of fauna and flora occurs through a slow process of natural selection/ survival of the fittest. This can only occur when the environment is changing as a exult of needing adaptations which best suit the environment. Evolution is not needed to suit a stable environment because organisms are already adapted to it. Physical changes (Water availability, temperature, light levels) and Chemical changes (such as salinity and pollutants such as acid rain or heavy metals) in the environment directly impact the evolution of flora and fauna.
This is due to the fact that current adaptations of an organism may no longer suit the new conditions. Consequently, better-adapted organisms survive and then reproduce to pass on the selective advantage. Competition for resources can lead to evolution so that one species can better exploit the existing resources. As a result of this selective advantage, the second species will experience a decrease in resources and only the fittest will survive. This will lead to modified anatomy, physiology or behavior. As a result, the second species may evolve to become the dominant species, leading to the 1st species to experience a change in environment (no resources). An example of this is the Peppered Moth of the United Kingdom.
In Industrial areas, the black variation of the moth dominates because it is camouflaged against the elution of black soot. Describe, using specific examples, how the theory of evolution is supported by the following areas of study: Paleontology Paleontology is the study of fossils. Fossils are the traces of any past life on Earth. Fossils that Darwin collected in South America were important in the development of his theory of Evolution by Natural selection. By comparison of fossils to extant organisms, similarities can be observed. The evolutionary explanation of this is that modern forms can only be descended from the animals that lived in this area in ancient times.