MIAB CRAP

• Distinguish between active and passive transport and relate these to processes occurring in the mammalian kidney:

- Active transport uses energy to transport substances across a membrane it would normally not be able to cross due to a diffusion gradient or its own properties - Passive transport is the movement of substances across a membrane without energy expenditure (this is diffusion and osmosis) - completely random. - A kidney is made up of around a million nephrons. It is within the nephrons that the processes of filtration, reabsorption and secretion occur. - The STRUCTURE of a nephron: • It is a long twisted tubule made up of sections: a Bowman's capsule, connected to (1) a proximal tubule, leading to the (2) loop of Henle, which connects to (3) the distal tubule. This all joins to the collecting duct which leads to the bladder. - The nephrons are densely surrounded by capillaries (this is to provide a large surface area for excretion). - Three processes occur in the nephrons (kidneys): • Filtration: Within the Bowman's capsule is the glomerulus, a dense clump of capillaries. The blood pressure here is so high that fluid and substance from the blood are forced into the Bowman's capsule, and form a fluid called the glomerular filtrate. It flows into the nephron and contains: ➢ Substances the body can reuse: Glucose, water, amino acids, etc. ➢ Wastes: Urea and poisons. • Reabsorption: The substances the body can reuse are reabsorbed into the capillaries surrounding the nephron. E.g. Vitamins and hormones. This is active transport and requires energy. Some other substances passively re-enter the blood. E.g. water by osmosis and salts by diffusion. This occurs in the proximal and distal tubules and in the loop of Henle (discussed in detail later). • Secretion: This is the process where the body actively transports substances from the blood into the nephron. Some toxins, such as urea, tend to diffuse back into the blood, so it must be secreted back into the nephron. It is also done to regulate salt and water levels again, or to remove additional toxins. This is active transport. • Halophytes are plants adapted to living in salty environments. They have: - Salt excluders on their roots - Salt filtration system - Excrete salt from the leaves • Xerophytes are plants adapted to arid and dry conditions. These include: - Thick leaves or a waxy cuticle - Small leaves, hairy leaves - Reflective leaf surfaces - Vertically hanging leaves - Thick bark to prevent wilting

Effects of substrate concentration on enzymes-

- Amount of compound present that the enzyme catalyses. Beyond a certain substrate concentration the rate of reaction is limited by the amount of enzymes. - An increase in the substrate concentration will increase the reaction until all the enzymes active sites are occupied, and then the reaction will occur at maximum rate. - In most enzymes the enzyme concentration is lower than the amount of substrate per molecule of enzyme. - So if the amount of concentration is increased then the rate of reaction will increase linearly. - But when the substrate concentration is increased and the enzyme concentration remains the same it will initially cause an increase in the substrate concentration until a point is reached at which the rate remains constant even if the substrate concentration is increased further. This point is called the saturation point (or Vmax or the maximum velocity). This is when all of the active sites on the enzyme molecules are occupied by a substrate and the reaction is proceeding at its maximum rate. - Further increases cannot increase the rate, as there are no more active sites available to which the substrate can bind. See graph below.

• Explain why the removal of wastes is essential for continued metabolic activity:

- As a result of metabolism, many waste products are formed (e.g. CO2) - If these were allowed to accumulate, they would slow down metabolism and kill the cells (e.g. excess CO2 increases pH, affecting enzyme function) - This is why they need to quickly be removed, or converted into a less toxic form. - When proteins and amino acids are broken down (in a process called deamination), a nitrogenous waste called ammonia, is produced - Ammonia is highly toxic and must be removed or changed to a less toxic form

Analyse information from secondary sources to identify the products extracted from donated blood and discuss the uses of these products. Analyse information from secondary sources to identify the products extracted from donated blood and discuss the uses of these products. Analyse information from secondary sources to identify the products extracted from donated blood and discuss the uses of these products.

- Determine whether the products from donated blood are a benefit or not. The main products extracted from donated blood are: • Red blood cells • Platelets • Plasma These products are spun in a centrifuge to separate them into different products. Further products can be extracted from the plasma. The uses and further products that can be extracted are outlined by the table below: BLOOD PRODUCT USE/TREATMENT Whole Blood To replace large amounts of blood from sever injury. Red Blood Cells Given to patients suffering from anaemia, (iron deficiency in the blood) and in cases of severe bleeding. White Blood Cells Given to patients with a low white blood cell count or in cases of severe bacterial infection. Plasma Given to patients after trauma, or following after a surgical procedure. Platelets Given to patients with severe haemorrhaging (bleeding) or bleeding due to diseases such as leukemia. Cryoprecipitate (contains blood clotting factors) Given to patients suffering from haemophilia A. Alternatively severe bleeding. Prothrombinex - HTTM (contains concentrated clotting factors.) Given to patients with specific bleeding disorders. These specific disorders pertain to patients who are missing certain clotting factors. Biostate (contains factor VIII clotting factor) Given to patients with haemophilia B. Monofix® - VF (contains Christmas factor) Given to patients with haemophilia B Thrombotrol® - VF Given to patients in situations whereby their blood is clotting too quickly. Albumin Administered to patients who are suffering from burns, shock due to blood loss and kidney/liver diseases. Intagram® P Given to patients who suffer from immune disorders such as AIDS, this in turn reduces susceptibility to infections. Hyper - immune globulins (contain - antibodies) Given to patients to treat and/or prevent specific infections such as tetanus or chicken pox. Rh(D) immunoglobulin (Anti - D) This product prevents haemolytic disease in newborn babies of Rh negative babies. Haemolytic disease basically pertains to the mother producing certain antibodies that destroy the baby's red blood cells.

• Explain why the processes of diffusion and osmosis are inadequate in removing dissolved nitrogenous wastes in some organisms:

- Diffusion and osmosis are both examples of passive transport, relying on random movements of molecules. - Diffusion is too slow for the normal functioning of the body and is not able to selectively reabsorb useful solutes. - Osmosis only deals with the movement of water and thus would only allow water to move out of the body, not the nitrogenous wastes. - In the kidney, some useful products are reabsorbed into the body - this would not be possible with diffusion (active transport needed) - Osmosis without active reabsorption of water would result in excess water loss - The kidney functions by using excreting all the blood substances in the nephron 'outside' the body and then selectively (actively) reabsorbing useful materials

Effect of temperature-

- Enzymes have optimum temperature for activity. Activity is how fast an enzyme catalyses a reaction (rate). Enzymes can be denatured (destroyed) by higher temperature. (In investigation) - To measure the affect of one factor others must be constant. All other variables (amount, type and environment of enzyme) must be constant. - Low temperature= low activity of enzymes, due to the fact that enzyme and substrate both have low energy. - High temperature= more molecules reacting due to activation energy, and an increase in reaction rate. - Optimum (Vmax) is 40oC this is when all of the enzyme molecules are acting at maximum capacity. - Effect of temperature directly related to the protein structure of the enzyme - As the temperature increases the enzyme activity increase, until it reaches its optimum temperature. - Due to the fact that the enzyme and substrate molecules are moving faster (rise in kinetic energy) and there are more collisions. (Can also look at prelim chem assignment) - If the heat is able to break the bonds that cause the protein to fold then it destroys the active site. Therefore the substrate has nothing to bond to and is therefore denatured. - At higher temperatures the shape of the enzymes changes, and they may be no longer able to accommodate the substrate. This causes an activity decrease, though if the temperature drops the activity will begin again. - At VERY high temperatures, the enzyme becomes denatured - destroy the characteristic properties of (a protein or other biological macromolecule) by heat, acidity, or other effects that disrupt its molecular conformation. E.g. the chemical bonds holding the protein molecules together are broken and the shape is changed permanently. When the enzyme is destroyed it can no longer accommodate the substrate and will remain inactive even if optimum temperature is returned. It is irreversible.

Explain why the maintenance of a constant internal environment is important for optimal metabolic efficiency

- Maintenance of a constant internal environment is important for optimal metabolic efficiency. - Environment includes (for example) temperature, pH and substrate concentration. If they do not remain the same then the rate of enzyme-catalysed reaction decreases. This could effect the entire pathway, which may produce something vital such as haemoglobin. - Regularly organisms take in nutrients and water to change their levels of activity. They are also exposed to frequent changes in external environments. Despite this they need to maintain an optimum constant internal environment for optimum metabolic efficiency, if the internal environment is stable (e.g. enzymes have their optimum temperature and pH conditions a high level of efficiency for the running of the cell is possible). - Enzymes are essential for proper metabolic functions in an organism - The efficiency is affected by temperature, pH and substrate concentrations. - Enzymes work best only in a limited range of environmental conditions. - Therefore a constant and stable internal environment is required so enzymes can be working at optimum rate, thus metabolism will be at optimum efficiency.

Outline the role of the nervous system in detecting and responding to environmental changes

- Nervous system provides rapid coordination of internal organ systems, and detects changes - The nervous system has two different parts- the central nervous system (CNS) and the peripheral nervous system (PNS). - The central nervous system controls all of an organisms responses - It also receives information and intitiates a response. It is a system of nerves around the body, which are connected to receptors and effectors. - The endochrine system plays a vital role in maintaining a balance. It secrets certain hormones which respond to different stimuli. - E.g. Thermoreceptors detect a change in the surrounding air temperature, (hot). A message from the PNS is relayed to the CNS, which in turn interprets the message. The CNS then initiates a response. Effectors start to produce sweat and dilate blood vessels in order to lose heat, and therefore maintain a balance.

Temperature ranges- Identify the broad range of temperatures over which life is found compared with the narrow limits for the individual species.

- Organisms live in environment with ambient temperatures, ranging from -70oC to 100 oC (e.g. bacteria in snow) to 100 oC (bacteria in hot springs and undersea vents from volcanoes). Ambient temperature is the external or environmental temperature. - Mammals can only live between 0oC- 45oC and are active in between 30-45 oC - Humans are unique due to culture and technology, which aids them to build devices to cope with higher temperatures outside biological temperature range. - For example most terrestrial organisms are found to function best between 0 - 45 degrees. Any higher or lower and the organism risks their cells and proteins denaturing, or their cells becoming frozen. In comparison thermoacidophiles love a hot climate around 100 degrees. If the temperature drops below 55 degrees the thermoacidophiles will eventually become inactive and die.

Explain the adaptive advantage of haemoglobin

- Oxygen, unlike carbon dioxide doesn't react to form an acid. Therefore it can only be held in a water state in solution. - If oxygen is carried in a solution of blood then blood would only carry oxygen in small amounts. - The haemoglobin allows the blood to hold more oxygen. This increases the oxygen carrying capacity of blood, in vertebrates. - The haemoglobin molecule structure is an adaptive advantage because it was a type of molecule, which means it can combine loosely on respiratory surfaces. - This allows the oxygen can flow freely in the capillaries. - Haemoglobin is enclosed in a blood cell; if it were just dissolved in the plasma it would disrupt the osmotic balance of blood. - During the development of red blood cells in mammals the nucleus is lost and after the cells acquire the haemoglobin - In blood (haeme) units are combined in groups of four, which means each individual haemoglobin carries four oxygen's. - This increases the rate and efficiency of oxygen intake and transport.

PH (definition)-

- PH is defined by a negative log to a base of 10 of the H+ concentration- E.g. - log10 10-2 = 2 - Measure of concentration of hydrogen ions released by atoms. Therefore describing acidity of a substance. Neutral is 7, neither acidic nor alkaline.

First hand investigation- Estimating the size of a red and white blood cell. Aim- To estimate the size of a red and which blood cells and draw scaled diagrams of each. Method- 1) Use a commercially available slide of human blood and gather a grid slide. 2) Use a diagram/ picture to identify the cells. Red blood cells contain no nucleus and white blood cells are larger and contain a nucleus. 3) Observe under a low power and then use the reference grid to determine the size of your field of view. Results- Red blood cells are 7 microns in diameter and are a more spherical shape and contain an obvious nucleus. Conclusion- White blood cells are larger than red blood cells.

- RED BLOOD CELLS (Erythrocytes): • Size: 6-9 µm • Shape: Bi-concave discs • Function: Transport of oxygen. • They have no nuclei; they only live for 3 months. After this they are destroyed in the liver or spleen. • 5-6 million in every millilitre of blood. • They are produced in the bone marrow - WHITE BLOOD CELLS (Leucocytes): • Size: 12-15 µm • Shape: Irregular shape; can change shape • Function: To defend against disease • Only 4-12 thousand per millilitre of blood • They are the largest blood cell • They have nuclei, unlike red blood cells • They are produced in the lymph glands. Explain the adaptive advantage of haemoglobin

Effect of pH-

- The charges on the surface of the enzyme molecule are essential for keeping the molecule folded so the active site can function properly. The charge pattern is determined by the charges of the ions (including hydrogen) in the solution in which the enzyme is dissolved. - Enzymes can only tolerate a small range of hydrogen concentrations within which it is active. In the range is the optimum pH, which maintains the active site, most efficiency. - If this is altered too much, on either side (lower or higher pH) then the enzyme molecule is distorted it will lose activity. - Changing pH slightly either side of the pH scale is reversible, but extreme alterations are irreversible. - Enzymes have specific pH (acidity) for activity e.g. stomach enzymes work best under pH of 6, - Changing the pH from the optimum reduces the enzymes activity. - PH is the measure of concentration of H ions per litre of solution. - Enzymes work best at their optimum pH, which is a very narrow range - Extreme affects of to the acidity or alkalinity will affect the bonds holding the 3D globular shape of enzymes, therefore denaturing the enzyme. - There are charges on the surface of the molecule. This keeps the molecule folded for a functioning active site. Enzymes have a small range on the pH scale they can tolerate, usually near neutral. Before and after this range the enzyme denatures.

• Identify the regions of the mammalian kidney involved in the excretion of waste products:

- The kidney is made up of three sections, the pelvis, the medulla and the cortex - The cortex contains the glomeruli. It is very dark red due to the capillaries - The cortex is involved in the filtration of blood - The medulla contains the nephron tubules, as can be observed by the striped appearance of the medulla - This section is involved in the reabsorption and secretion of substances - The pelvis is where all the collecting ducts connect to - The collecting ducts reabsorb water - The renal artery, renal vein and ureters are all connected to the pelvis.

• Explain how the processes of filtration and reabsorption in the mammalian nephron regulate body fluid composition:

- The nephron is a regulatory unit; it absorbs or secretes substances in order to maintain homeostasis. - This regulation maintains the constant composition of body fluids. - Salts and water are adjusted to maintain fluid concentration - Different ions also adjusted to maintain pH. - These different processes happen in the different sections of the nephron. - Proximal Tubule: • Bicarbonate ions are reabsorbed into the capillaries into the blood from the nephron, hydrogen ions are secreted out. This maintains the pH of the blood. • Drugs, such as aspirin, penicillin and poisons are secreted out of the blood • Regulation of salts also occurs here. Sodium ions are actively reabsorbed and chlorine ions follow passively. Potassium ions are also reabsorbed - The Loop of Henle: It has a descending limb and an ascending limb • In the descending limb, it is permeable to water, not salt. • Water passes out of the nephron and into the capillaries by osmosis • In the ascending limb, the walls are permeable to salt, but not water ➢ Ascending limb is thin-walled at the bottom, and thick-walled at the top. • Salt passively passes out into the capillaries at the bottom, thin-walled section, but is actively passed out in the top, thick-walled section. - The Distal Tubule: • Selective reabsorption of sodium ions and potassium ions occurs here again, to regulate the pH of the blood, and the concentration of salts. - The Collecting Duct: • This is the end of the nephron, and connects to the ureters. • The walls are permeable to water only, and water is transported out accordingly to the needs of the body • The final filtrate is called urine.

• Identify the role of the kidney in the excretory system of fish and mammals:

- The primary role is osmoregulation. - This is the regulation of salt and water levels in the body - Fish do not excrete nitrogenous wastes through the kidneys; they use their gills - Their urine contains mainly excess water and salts - Mammals' urine contains urea as well as water and salts

Identify the role of enzymes in metabolism, describe their chemical composition and use a simple model to describe their specificity in substrates

- The role of enzymes- Enzymes is organic catalysts (something which speeds up or brings a chemical reaction with out being used itself) it speeds up reactions and allows them to occur at lower temperature, this means that body temperature does not have to be higher.

• Explain why the concentration of water in cells should be maintained within a narrow range for optimal function:

- Water makes up around 70-90% of living things; it is essential for life - Water is the solvent of all metabolic reactions in living cells, and sometimes directly takes part in it (eg. Respiration) - RECALL: • Isotonic: Concentration of solutes outside the cell is the same as inside the cell. No overall movement of water. • Hypertonic: Concentration of solutes is greater outside the cell than inside. Water tends to move out of the cell. • Hypotonic: Concentration of solutes is greater inside the cell than out. Water tends to move inside the cell. - Living cells work best in an isotonic environment - The levels of water in cells needs to be kept relatively constant - Any change in the concentration of solutes will result in a change in the levels of water in cells which usually results in death (either dehydration or cell bursting) - Enzymes also require specific conditions of functioning, some of which could relate to the levels of water and solutes in cells. - This is why the concentration of water must be kept constant: To ensure the proper functioning of living cells.

Analyse information from secondary sources to identify current technologies that allow measurement of oxygen saturation and carbon dioxide concentrations in blood and describe the conditions under which these technologies are used:

1. What are the current technologies? - ABG (arterial blood gas) analysis o Measures the amount of oxygen and CO2 in blood. o It evaluates how efficiently the lungs and delivering oxygen and getting rid of carbon dioxide. o It measures the partial pressure of oxygen and carbon dioxide, oxygen content and saturation, bicarbonate content and blood pH. o Oxygen saturation is the amount of oxygen actually combined with the haemoglobin compared to the total amount of oxygen it is actually able to combine with. o Arterial blood is collected for this type of analysis. o Uses electrochemical methods Pulse Oximeter: − A pulse oximeter is used for monitoring oxygen saturation (oxygen levels). − It is attached to a finger and uses the transition of light through the tissues to measure oxygen saturation. − This method has its advantages because it is painless, easy to apply, quickly to give results and non-invasive and provides continuous monitoring for patients undergoing anaesthesia or medical ventilation. − Can also be used as a general check-up procedure to analyse O2 levels − This is gained due to the large difference in red light absorbed by the haemoglobin compared to oxyhaemoglobin. 2. The conditions under which the technologies are used- − To assess respiratory diseases and other conditions affecting/or may affect the lungs. E.g. pneumonia and silicosis. − It is used to manage patients receiving oxygen therapy, mechanical ventilation, and anaesthesia, in intestine care, in accident and emergency facilities or for premature babies. − Test of blood pH also provide information on how well the kidneys and lungs are maintaining blood pH. − As a response to signs of low oxygen or high carbon dioxide levels. − For diagnoses and monitoring of patients Pulse Oximeter: − Also used during surgeries, to monitor patients under anaesthesia. − And used to monitor premature babies that are in neo-natal wards. − Used in many conditions - this is because it is painless, easy to apply and quick to give results. − Can also be used as a general check-up procedure to analyse O2 levels.

• Describe adaptations of a range of terrestrial Australian plants that assist in minimizing water loss

Adaptations for minimizing water loss: - Tough coverings on leaves, reduced size of plants leaves and stems, sunken stomata or stomata protected by hairs, water storage, loss of leaves or branches - Modifications to leaves and stems, namely Phyllodes and Cladodes, small flowers or flowers without petals, extensive roots. Example: The Eucalyptus flower has no petals. This is another adapation to minimize water loss, as the presence of flowers requires metabolism and therefore water. Example: Acacia (a sclerophyll) are plants with leaves that have a leathery, hard or spiny covering that may help it minimize dehydration.

Describe the main changes in the composition of the blood as it moves around the body and identify tissues in which these changes occur:

Chemical Composition of the blood as it moves around the body Tissues in which these changes occur- − Blood receives oxygen and carbon dioxide is released. − Blood enters via the right atrium of the heart via the vena cava (major vein) − Blood which enters is high in carbon dioxide − Blood is low in glucose and other nutrients; it is also high in urea, other nitrogenous wastes and various poisons. − As the heart beats, the right ventricle pumps the blood through the pulmonary artery, to the lungs − Where the blood gains oxygen, and loses carbon dioxide. − The blood then enters the left atrium via the pulmonary vein. Lung tissue − Blood receives carbon dioxide and released oxygen − The left ventricle pumps oxygenated blood to the body through the aorta. − The blood loses oxygen and gains carbon dioxide in all body cells, as respiration occurs. Glucose levels also drop. General body tissue e.g. Skin tissue − Water diffuses into the blood. Some substances e.g. alcohol pass into the stomach tissue from the blood through the walls of the stomach Stomach tissue − Digested food, amino acids, glucose- diffuse into the blood and go to the liver. Fatty acids go to the lymph. Small intestine tissue − Glucose is regulated (added or removed) and some poisonous/unwanted substances are removed. Excess vitamins, ions, lipids are removed. Excess amino acids are removed and converted into ammonia, and then into urea, which is added to the blood. − Poisons are also reduced, as the liver changes them to less toxic forms Liver tissue − Water/salts/vitamins absorbed in large intestine and passed into blood. Large intestinal tissue − Urea, excess water, salts removed from blood excreted. Kidney tissue − Hormones are secreted directly into the blood stream. Endocrine tissue

Explain that homeostasis consists of two stages • Detecting changes from the stable state; • Counteracting changes from the stable state

Coordination in animals is controlled by two different systems- - The nervous system - The endocrine system (hormonal system) In plants it is run by the hormone system- - In plants the hormone system brings about coordinated functioning of organ systems. - The feedback mechanisms are self-regulating systems that maintain a balance or homeostasis. It is any circular process where information is fed back to the central control region. E.g. the human body uses feedback mechanisms to deal with changes in body temperature. Stage 1- Detecting changes from the stable state: - Receptor detects changes- stimulus - Body needs to remain in 'stable state' in order to function properly - The changes/deviations to the stable state are a result of changes to the external and internal environment. - These changes provoke a response called a stimulus. - Receptors detect stimuli, to which the organism then reacts to the change. - Internal Stimuli- Light, day length, sound, temperature, odours - External Stimuli- levels of CO2, oxygen levels, water, wastes, etc. inside the body. - Receptors can range from a patch of sensitive cells (e.g. tongue) to complex organs such as eyes and ears. - If human body temp rises, the brain is stimulated by the rise in blood (using the anterior hypothalamus) - Also when a mammal is exposed to the cold the skin receptors increase their activity sending nerve impulses to the posterior hypothalamus. In Plants- - Plants can detect gravity, light intensity and direction and the length of a period of darkness. Stage 2- Counteracting changes from the stable state: - Effectors control change. - After the receptors detect change the organism then reacts to the change. - The response will counteract the change in the stable state so that it is once again maintained. - Effectors- They bring about responses to the stimuli - Effectors can be muscles or glands- Muscles bring about change by movement, glands bring about change by secreting chemical substances. - After detecting the rise in body temp. The hypothalamus them stimulates heat loss by increasing the blood circulation through the skin, increasing sweat and decreasing metabolic activity and muscular activity. Thus lowering body temperature. - After detecting the drop in temperature, activity in the posterior hypothalamus stimulates the sympathetic nervous system to activate mechanisms that conserve heat. In Plants- - Plants after detecting and increase in concentration of fluids, release abscisic acid from chloroplasts so that there is a closing of stomates and an increase in the production of watertight resins.

• Define enantiostasis as the maintenance of metabolic and physiological functions in response to variations in the environment. Discuss its importance to estuarine organisms in maintaining appropriate salt concentrations.

Estuarine organisms such as fish and other invertebrates carry out enantiostasis in order to maintain a suitable internal salt concentration. Estuarine fish maintain a solute concentration in their cells that is similar to the external salt concentration in the estuarine water. They do this by moving small organic molecules in and out of their tissues. The amount of movement of these molecules depends on the salt concentration of the estuarine water. This is important so that metabolism and other process can proceed efficiently.

Gather, process and analyse information from secondary sources and use available evidence to develop a model of a feedback mechanism

Evidence to suggest developing a model of a feedback mechanism- Models in bio can be physical representations such as the model of a DNA molecule, abstract representations, including mathematic expressions or diagrams of ideas and explanations. While models may be criticised for over-simplification nature, they are a tool, which can support understanding, making predictions and further investigations. Models can be based on analogy. A model of a non-living feedback system is the thermostat that controls temperature to a set level in a room. It has a device which measure whether temperature is too low and turns on the cooling system and hot vice versa. This is a negative feedback mechanism, when negative feedback occurs at the increase in the factor is sense and the response is stopped. Think of tank and thermostat. The role of the nervous system in detecting and responding to environmental changes- The nervous system provides rapid coordination of the internal organ system and detects and responds to environmental changes. The nervous system consists of the central nervous system (brain and spinal cord) and peripheral nerves. Special endings of the sensory nerves, such as heat sensors in the skin, which detect stimuli such as, heat pressure or chemical conditions. The receptors relay messages that are processed by the central nervous system and then conveyed to effector organs or muscles that respond.

• Process and analyze information from secondary sources and use available evidence to discuss processes used by different plants for salt regulation in saline environments

Halophytes are plants adapted to living in salty environments. They use a number of processes to enable them to regulate their salt levels like: Salt Exclusion- salt tolerant plants are often able to stop salt from entering their tissues. In most halophytes the roots are able to prevent about 95% of the salt in the soil water from entering. Control of salt movement- Salt levels in the xylem are kept low by salt remaining in the roots or entering older parts of the plant. Xylem sap reaching young leaves and flowers (the growing points) have a very low salt concentration. Older leaves with accumulated salt drop regularly from the plant. Salt Excretion- Leaves of some halophytes actively excrete salt. Salt glands move salt from the leaf tissues to the surface of the leaf. Here the salt crystallizes and is then blown or washed away. Some plants have leaves with salt bladders where salt accumulates. The bladders often burst, releasing their contents onto the surface of the leaf. Osmotic Adjustment - Halophytes usually have a higher concentration of dissolved substances (solutes) in their cells than salt sensitive plants. They may maintain this by producing and storing organic compounds such as glycerol. Unlike high salt levels, these compounds are not damaging or toxic to the cells. In aquatic algae and sea grasses this helps maintain a balance between the concentration inside the plant cells and the sea water outside. Thus plants in saline environments need to regulate their salt levels to survive because too much salt affects the functioning and health of the plant.

Describe homeostasis as the process by which organisms maintain a relatively stable internal environment

Homeostasis is the process by which organisms maintain a stable internal environment- - Blood temperature should be around 37oC and blood pH around 7.38-7.42, blood sugar should remain around 90mg/ 100mL of blood. - Homeostasis is the process, which organisms use to maintain their optimum temperature even when affected by limits caused by changes in external environment, behaviour. They adjust this through changing their psychological process. - Homeostasis- 'staying similar' or 'unchanging'. Refers to the 'steady state' of an organism. - Homeostasis can occur in living and non-living things, but is more common in vertebrates. - Homeostasis is called a self-regulation in non-living things, and homeostasis in living things. - Receptors are constantly monitoring - Control centre compares stimulus with the set point. - Effectors carry the message - Homeostasis first begun by Claude Bernard in 1859. Though he didn't call it this, a man named Walter Cannon did in 1929. - They may be self regulating- e.g. a thermostat, which has certain vital parts: o A system where a set value must be maintained o A detector device, which sends feedback o A control centre, which responds to the feedback o A regulator, which corrects any deviations from the set value. - Living things need to control their- • Body temp and metabolic rate. • Concentrations of dissolved salts and minerals • Concentration of nutrients, e.g. glucose in blood. • Input and output of water • Amount of nitrogenous wastes • O2 and CO2 concentrations. • Removal of malfunctioning cells or foreign substances. - These systems monitor all the activities of cells, their requirements and the wastes produced- to maintain health. - The internal environment of cells are kept within the certain limits of the coordinating systems of the body o Non-Living: refrigerator or lab bath: required temperature set on a thermostat. It is switched on, a sensitive thermometer (detection system) gives feedback to control centre. Activates/ turns off heater to cool and heat to get to ideal temp. • Needs: set value, detector device (which sends feedback), control centre and a regulator. o Living: needs a receptor, a control centre and an effector to carry out homeostatic levels. Receptor plays roll of the detector and monitors changes. Responding is done by the effector. This takes place in two stages: detection and responding.

- The products are the substances, which the substrate(s) becomes, one substrate can be split in two or can be two substances joined. - Enzymes are only needed in small amounts. - Enzymes are unique to one substrate. The enzyme combines to the substrate so that a chemical reaction can take place. - A substrate, which is altered and no longer 'fits' the enzyme- so the enzyme is released. Further research proved this. - The lock and key model assumes that an enzyme has a rigid unchanging shape. - Other models assume that the active site is more flexible and can be changed to the different substrate it is binding to. Like the shape of a sock when a foot is placed in it. This is called the induced fit model.

Specificity of enzymes

- Enzymes control

all chemical processes of living processes. Enzymes are produced within cells.

They are made of

amino acids, which are linked and folded shape, which makes a three-dimensional protein structure.

- The shape allows it to

attach to reactant molecules

- Without enzymes the metabolism would be

be too slow to support life.

- Provides an alternative pathway for a

chemical reaction to occur.

- The protein structure is related to

enzyme specificity.

The long chains of amino acids are

joined together by peptide bonds

- Most of the time the enzyme molecule is

larger protein molecule bigger than the substrate.

- There are six groups including-

o Oxido-reductases catalyse oxidation and reduction reactions. o Transferases transfer chemicals hydrolysis reaction (reactions in which molecules are broken frown into smaller molecules and water is added). o Lyases catalyse reactions that remove or add double bonds to molecules o Isomerases catalyse reactions on which the atoms in molecules become differently arranged in space, which means one isomer is converted into another. o Ligases (or synthetases) catalyse the joining or 'sticking together' of two molecules.

Describe the main changes in the composition of the blood as it moves around the body and identify tissues in which these changes occur:

o PULMONARY CIRCUIT (Lungs): • Blood enters the right atrium of the heart via the vena cava (major vein): • The blood is deoxygenated, and high in carbon dioxide • It is low in glucose and other nutrients; it is also high in urea, other nitrogenous wastes and various poisons. • As the heart beats, the right ventricle pumps the blood through the pulmonary artery, to the lungs: • Here the blood gains oxygen, and loses its carbon dioxide. • The blood then enters the left atrium via the pulmonary vein. o SYSTEMIC CIRCUIT (Body): • The left ventricle pumps oxygenated blood to the body through the aorta. • In the body, various changes occur to the blood. • The blood loses oxygen and gains carbon dioxide in all body cells, as respiration occurs. Glucose levels also drop. • In the LIVER: • Levels of glucose are regulated - excess glucose is changed to glycogen, or glycogen stores are changed to glucose (if needed) • Excess amino acids are changed to ammonia, and then to urea • Poisons are also reduced, as the liver changes them to less toxic forms • In the INTESTINES: • Levels of nutrients from digestion increase. • Glucose, amino acids, ions, lipids and other substances from food enter the blood. The increase is through the small intestines reabsorption of food • In the KIDNEYS: • Salt and water levels are regulated • All urea is removed, toxins are excreted into the urine • The changed blood, again highly deoxygenated, then flows back to the pulmonary circuit. Oxygen in cells Describe current theories about processes responsible for the movement of materials through plants in xylem and phloem tissues- Transport in Plants o Xylem of flowering plants consists of xylem vessels, tracheids, fibres and parenchyma o Water and minerals rise through the xylem through pressure from the roots and vacuums from the leaves. o Phloem consists of fibres, parenchyma, sieve cells and companion cells. Processes involved in the transpiration stream

- Most enzymes made of

proteins

− Cofactors are

small molecules, which help enzymes to act. The inorganic (metallic) ions such as Zinc and Calcium are cofactors. If they are organic molecules they are coenzymes. Without these cofactors or coenzymes they cannot catalyse the reaction. The coenzymes generally bind to the active site, and cofactors generally bind to the active site or the coenzyme, if it has a coenzyme.

- The reactant is called the

substrate and the substrate that is not is called the active site.

- This is due to the fact that the shape of the enzyme must fit

the shape of the substrate material.

Endotherm-

• Controlling Exposure: The goanna controls its body exposure to the sun by sun baking in the cool morning, and staying in shade during the hot hours. • Hibernation: The Bogong moths "hibernate" in hot weather (this is called aestivation). During summer, they gather in caves, their metabolism slows and the body temperature drops. This is to maintain body temperature. • Shelter: The central netted dragon stays in sheltered areas to avoid extreme heat. They can dig burrows or seek shelter in caves or crevices. This reduces the effect of heat on their body. • Nocturnal Activity: Brown snakes can change into nocturnal animals when the temperature becomes very hot. Many desert animals sleep in burrows during the day and are active at night, to escape the heat. • Bearded dragon- Pogona vitticeps

Identify the role of the kidney in the excretory system of fish and mammals-

• Kidney has a duel role- o Excreting nitrogenous wastes o Maintaining a water balance in mammals and fish. o It is also an organ of filtration, reabsorption and secretion. • When amino acids are broken down they create ammonia, which is highly toxic, very soluble and diffuses readily across cells • In fish it is dissolved out through the gills and released into water in small amounts. • In mammals, sharks and some bony fish liver convert ammonia to urea, which is less toxic and releases less water. • The blood carrying the nitrogenous waste is brought from the renal arteries into the kidneys. • Urine is formed in the cortex and the central medulla. • The pelvis is connected to the medulla to the ureter which takes the urine to the bladder for short-term shortage. • Depending on the environment of fish and mammals, the kidneys excrete urine in different concentrations including- o Concentrated urine in ranges of concentrations, such as high in fish and low water in mammals. o Freshwater fish excrete dilute urine resulting from the influx of water from their environment. o They can also reabsorb water into the bloodstream and help overcome water balance problems resulting in an influx of water flowing into the environment. • The primary role is osmoregulation. • This is the regulation of salt and water levels in the body • Fish do not excrete nitrogenous wastes through the kidneys; they use their gills • Their urine contains mainly excess water and salts • Mammals' urine contains urea as well as water and salts • The kidneys ensure that the concentration of blood and interstitial fluid is constant

Explain why the removal of wastes is essential for continued metabolic activity:

• Metabolic wastes- from reactions are o Some are poisonous o They take up space • Alter the process of osmoregulation. • As a result of metabolism, many waste products are formed (e.g. CO2) • If allowed to accumulate, they would slow down metabolism and kill the cells (e.g. excess CO2 increases pH, affecting enzyme function) • Need to quickly be removed, or converted into a less toxic form. • When proteins and amino acids are broken down (in a process called deamination), a nitrogenous waste called ammonia, is produced o Ammonia is highly toxic and must be removed or changed to a less toxic form • This is controlled by the excretory system- in humans is o Kidney o Lungs (CO2) o Skin. • The excretory system also maintains constant blood composition and thus a constant internal environment in cells.

Ectotherms-

• Migration: The short-tailed shearwater migrates to equatorial regions during the winter months. This is to avoid the cold weather, as the bird only breeds in warm weather. • Insulation: The superb parrot contracts the muscles controlling its feather in cold conditions, fluffing up its coat. This maintains a later of trapped air as insulation. This air reduces heat exchange with the environment. • Evaporation: The red kangaroo licks its arms to cool itself. The evaporation of the saliva cools its skin. • Nocturnal Behaviour: Hopping mice, and many other Australian endotherms, are nocturnal. This is to prevent overheating, and to reduce moisture loss.

Explain why the processes of diffusion and osmosis are inadequate in removing dissolved nitrogenous wastes in some organisms:

• Osmosis is a special form of diffusion where it passes through a semi permable membrane that allows the movement of water- but not larger molecules. Osmosis results in movement of water from a dilute solution to a stronger solution. • It is inadequate because it- • Diffusion is too slow and non-selective to solutes • Not enough concentration gradient. • Osmosis would mean that waste would stay in the body and water would leave. • Result would be to have a kidney that dumps everything outside the body, but selectively reabsorbs the still useful materials. • Diffusion and osmosis are both examples of passive transport, relying on random movements of molecules. • In the kidney, some useful products are reabsorbed into the body - this would not be possible with diffusion (active transport needed) • Osmosis without active reabsorption of water would result in excess water loss • The kidney functions by using excreting all the blood substances in the nephron 'outside' the body and then selectively (actively) reabsorbing useful materials

Explain why the concentration of water in cells should be maintained within a narrow range for optimal function-

• Water is a good solvent • Dissolves many other substances so that they can react. • All reactions in the body take place in water. • This is one main function is as a medium for chemical reactions. • This means that its concentration must remain constant, as amount of water= concentration of materials in the cell. • Water has high specific heat capacity= large heat= small change • Therefore good as water temperature stays constant. o Makes up around 70-90% of living things; it is essential for life o Water sometimes directly takes part in it (eg. Respiration) o Know- • Isotonic: Concentration of solutes outside the cell is the same as inside the cell. No overall movement of water. • Hypertonic: Concentration of solutes is greater outside the cell than inside. Water tends to move out of the cell. • Hypotonic: Concentration of solutes is greater inside the cell than out. Water tends to move inside the cell. o Living cells work best in an isotonic environment o The levels of water in cells needs to be kept relatively constant o Any change in the concentration of solutes will result in a change in the levels of water in cells which usually results in death (either dehydration or cell bursting) o Enzymes also require specific conditions of functioning, some of which could relate to the levels of water and solutes in cells. o This is why the concentration of water must be kept constant: To ensure the proper functioning of living cells.

Compare the structure of arteries, capillaries and veins in relation to their function

− Arteries: o Sends from heart to body cells. o Thick muscular walls o No valves o Carry blood away from heart o Carries oxygenated blood (ex. Pulmonary artery) o Carried under pressure (pumped) (high blood pressure) o The pressure creates great stress in the arteries o This gives reason to why they are thick walled, elastic and muscular. o They have muscle fibres in them, which can contract and relax meaning they not motionless. o The contracting maintains the pressure of the blood, so that the blood travels in spurts towards the body tissues (this also creates the pulse on your wrist or neck). o The muscle fibres of the arteries also maintain the rate of the flow of blood. CS- − Veins: o Carry blood back to the heart o This is why they have thinner walls than arteries, less muscle and a wider diameter (large lumen). o Valves present- Since there are no thick muscular walls to keep the blood pulsing along to prevent backward flow of blood o Carries blood to the heart o Carries deoxygenated blood o Carried under low pressure: from movement via muscles as you use these muscles, they press on the veins, pushing blood through the veins o Veins are not under a lot of stress - blood pressure is low • CS- • CONNECTIVE TISSUE • ELASTICFIBRES/SMOOTH MUSCLE • ENDOTHELIAL LAYER • NOTE THE VALVE − Capillaries: o Thin, tiny blood vessels in every cell of the body, and at every entry or exit point. o An extension of the inner layers of the arteries and veins o Connect arteries and veins o Thin-walled because only one cell thick o This means that only one red blood cell can pass at a time. o Thus, providing a very large surface area over which exchange of materials between blood and body cells can occur. CS- NOTE THAT THE WALL OF THE CAPILLARY IS VERY THIN COMPARED TO THAT OF THE OTHER BLOOD VESSELS.

Identify the forms in which each of the following is carried in mammalian blood: • Carbon Dioxide • Oxygen • Water • Salts • Lipids • Nitrogenous wastes • Other products of digestion

− Multicellular organisms must meet the requirements of each individual cells which it has in it. Water is an excellent fluid transport solvent due to its strong molecular bonds and solvent ability of nutrients. − Blood consists of cells and cell like bodies which are carried in a watery fluid called Plasma. − There are 5 million red blood cells per cubic centimetre of blood. − Carbon dioxide is carried in a solution of plasma as bicarbonate ions. − Oxygen is carried as an oxygen haemoglobin contamination in the blood cells. − Water is carried as blood plasma, which contains 90% water. − Salts such as Na, K, Mg, Cl, Su, and pH ions are all transports in a solution of plasma. Iron also forms a loose combination to plasma proteins forming a transferring ion complex. Carbon + Water Carbonic Hydrogen + Hydrogen Dioxide Acid Ions Carbonate Ions CO2 + H2O H2CO3 H+ + HCO3-1 − Lipids- most are absorbed by the digestive system into the lymph as glycerol and fatty acids in plasma. Mostly in the blood as glyceride phospholipids and cholesterol that is associated with plasma proteins. − Nitrogen gas- Mostly in the form of urea with small amounts of ammonia (NH3). − Other products include amino acids, glucose which are suspended or dissolved in the plasma.

Identify some responses of plants to temperature change

− Plants need certain temperature for growth/germination of seeds. − Land temperature changes more on land than in water. − Plants response includes: o Orientation of leaves vertically to reduce SA exposed to sun. o This allows for heat absorption and supporting convection cooling o Ability to drop leaves in cold. o Germination of seeds after certain periods. E.g. some seed will only germinate after a certain period of cool. o Budding increase when temperature/ length of day increases in spring. o Closing of stomates in high temperature to reduce water loss (uses guard cells). o Desert plants or plants which are exposed to high temperatures elicit a few responses due to temperature change. For example due to increasing temperature a desert plant will have smaller leaves which in turn decreases their surface area which leads to a decrease in water loss and solar radiation. o An Australian example where a plant reacts to temperature change is the eucalypt. The eucalypts leaves hang down, vertical in nature. This in turn provides a large surface area for the rising sun, and at this time of the day it is generally cool in nature. When the sun is higher in the sky around midday, the ambient temperature generally increases. At this time the eucalypts leaves are still hanging vertically which in turn reduces the surface area of the leaf as well as maximising water retention. In some very dry and hot conditions the eucalypt may even close its stomates in order to stop transpiration from occurring.

Compare responses of named Australian ectothermic and endothermic organisms to changes in the ambient temperature and explain how these responses assist in temperature regulation:

− Two different places where the body has different temperatures- the core temperature and the shell temperature. The core includes the main organs, within the skull, chest and abdominal cavities. The core includes further than these areas in hotter environments. The shell temperature includes the skin and peripheral temperatures. − Ectotherms cannot generate own body heat or maintain body temp. The ectotherms are greatly affected by the temperature and environment around them. Its own metabolic processes do not produce heat for these animals rather by the environment around them. − Most animals are ectotherms. − Includes reptiles, fish and some insects. − Endotherms can generate their own body heat. Their body temperature is controlled by their metabolic processes and adaptive mechanisms, which control the rate of heat exchange with the external environment. − These mechanisms include panting, sweating and insulation (fur, feathers), reduced blood flow, hibernation and burrowing. One of the most important mechanisms is the ability to increase surface area to volume ratio, using things such as curling into a ball. − Ecotherms can retain active within a wider range of temperatures from high heat to cool nights. − The ability to maintain a constant temperature allows greater geographical and ecological distribution.