Most Organisms Are Active in a Limited Temperature Range

Maintaining a Balance

Most Organisms are active in a limited temperature range

Students Learn to

Identify the role of enzymes in metabolism
- Metabolism refers to all the chemical reactions occurring in an organism
- Enzymes are biological catalysts which increase the rate of the reaction
- Enzymes lower the energy requirement of reactions allowing them to occur faster

Describe their chemical composition
- They are specialised proteins (Carbon, Hydrogen, Oxygen, Nitrogen)
- they consist of one or more polypeptide chains which are composed of long chains of amino acids
- they have an ‘active site’ which attaches to its specific substrate to induce a chemical reaction

Use a simple model to describe their specificity in substrates
- they are specific to one chemical or substrate, when they combine this is known as the enzyme-substrate complex.
- The Lock and Key Model assumes the enzyme has a fixed rigid shape which fits the substrate
- The Induced-Fit Model suggests the enzyme has a flexible shape which moulds to the specific substrate
- both models are based on a matching shape between enzyme and substrate and explain specificity.

Identify pH as a way of describing the acidity of a substance
- Hydrogen ions cause acidity level, pH is the measure of acidity/alkalinity of a substance through the concentration of Hydrogen ions per litre of solution
- pH scale: 0-14, 7 is neutral (pure water) 14:alkaline, 1:acidic

Explain why the maintenance of a constant internal environment is important for optimal metabolic efficiency
- Enzymes are essential for metabolic efficiency and work best in a limited range of factors known as homeostasis
- as a result of optimal conditions, metabolic efficiency is optimal due to efficient enzyme activity

Describe Homeostasis as the process by which organisms maintain a relatively stable internal environment
- Homeostasis is the maintenance of a balanced or stable internal environment involving conditions such as Temp, pH/blood sugar levels and CO2/H2O/O2/urea concentration within a limited range. It involves two stages; detection of change and carrying out a response to counteract it.

Explain that homeostasis consists of two stages; DETECTION and COUNTERACTING
- The external (Temp, light) and internal (h2o/CO2 conc.) STIMULUS (from their environments) cause deviation from stable, RECEPTORS (photo/chemo) interpret it
- The CNS stimulates EFFECTORS (muscles/glands) to counteract this and return stability by triggering a response
- the internal environment is like a see-saw and is constantly receiving stimulus and effecting response

Outline the Role of the nervous system in detecting and responding to environmental changes
- works to regulate and maintain internal environment in response to stimulus (stimulus control pathway)
- CNS: the control centre for all the body’s responses, coordinating responses by receiving info from receptors, interpreting it and initiating response.
- PNS: branching system of nerves that connects receptors and effectors, it transmits messages from the CNS and back, acting as a communication channel.

Identify the broad range of temperatures over which life is found compared with the narrow limits for individual species
- Living things can be found in temps from -70 degrees Celsius to 120 degrees Celsius
- Survival in specific temperatures is dependent on activity levels, metabolism. Most exist and are active between 0-45 degrees Celsius as this is when most enzymes denature
- Procaryoticthermophiles usually found in deep sea vents at 110 degrees Celsius, Arctic animals for cold

Compare responses of named Australian ectothermic and endothermic organisms to changes in the ambient temperature and explain how these assist in temperature regulation
- Ectotherms such as the;
Goanna controls its exposure to the sun,
Bogong moths hibernate in hot weather, during summer they gather in caves and slow their metabolism to drop body temperature.
Central netted dragon stays in sheltered areas, dig burrows, reducing effect of heat
brown snakes can become nocturnal to escape the heat
- Endotherms such as the;
Short-tailed Shearweather migrates to equatorial regions during winter and only breeds in warm weather
Superb Parrot fluffs up its coats by contracting muscles to insulating by trapping air
Red Kangaroo licks its arms, the evaporation of the saliva cools the skin
Hopping mice are nocturnal to prevent heating and moisture loss

Identify some responses of plants to temperature changes
- The Eucalyptus tree alters its growth patterns, growing most in spring with its beneficial environmental conditions
- in extreme heat or cold, plants can die but leave dormant seeds to wait for better conditions
- Australian Sclerophyll trees have vertical leaves to reduce sun exposure
- plants may die above ground but leave bulbsand roots to survive underground to grow when favourable cond. Return

Students:

Identify data sources, plan, choose equipment or resources and perform a first-hand investigation to test the effect of;
INCREASED TEMPERATURE on the activity of named enzymes
- Sensitivity to temperature relates to the protein structure of enzymes
- TREND: Activity levels increase until its optimum temperature because collisions between enzyme/substrate are more common. When the temperature goes past this level, activity slows until the enzyme denatures.
- EXPERIMENT: 7 stations, each testing a different temp(10-70 degrees celsius) using water baths and thermometers. Place 3ml of milk in 14 test tubes, labelling 7 A and the other 7 B. For each temp there is an A & B TT, allow to sit for ten minutes, add crushed junket tablet and shaking in all the A’s. Examine all tube every 10 minutes.
- ENZYME: catalase (in milk), SUBSTRATE: Rennin
IND VARIABLE: temperature
DEP VARIABLE: amount of enzyme activity
CONTROL: test tubes B
VALID:the use of a control ensures this
RELIABILITY:
ACCURACY:

CHANGE IN PH on the activity of named enzymes
- Enzymes work best at a neutral pH (the same as blood)
- EXPERIMENT:
IND VARIABLE:
DEP VARIABLE:
CONTROL:
VALID: the use of a control ensures this
RELIABILITY:
ACCURACY:

CHANGE IN SUBSTRATE CONCENTRATIONS on the activity of named enzymes
- 5 test tubes with varying concentrations of substrate, eg filling one with all water, filling another with all substrate and another half and half etc. Using a borer for equality get 5 pieces of potato (catalase) and insert all at the same time, the height of bubbles indicates amount of enzyme activity.
TREND: activity will peak when all active sites are in use, then they will proceed at a maximum rate
IND VARIABLE: concentrations of substrate
DEP VARIABLE: amount of enzyme activity
CONTROL: equal catalase
VALID: tests what it is supposed to, the use of a control ensures this
RELIABILITY: repetition
ACCURACY: use of borer for equality, test tubes are a fitting size, pipette

Gather, process and analyse information from secondary sources and use available evidence to develop a model of a feedback mechanism
- in a feedback mechanism the response is carefully monitored, the response becomes the new stimulus and changes need to be made constantly. As most are a counteraction, feedback is usually negative (opposes the initial stimulus).
- Photoreceptor/machnoreceptor/chemoreceptor/thermoreceptor
- Stimulus – receptors – control centre – effector – response
- Inc body temp – thermoreceptor – hypothalamus – sweat glands – perspiration
- high blood sugar level – chemoreceptor – hypothalamus – pancreas makes insulin – low BS level
- Low BS level – chemoreceptor – hypothalamus – Liver makes glycogen – high BS level

Analyse information from secondary sources to describe adaptations and responses that have occurred in Australian Organisms to assist temperature regulation
Behavioural Adaptations (Ectotherms)
- increase exposure to sun, seek shade and burrow and be nocturnal
Physiological
- Hibernate (known as Torpor) by lessening movement / activity which slows the metabolic rate
Structural
- scales (I don’t know what this would do...)
- Colour of skin – eg black skin to attract heat

Behavioural adaptations (Endotherms)
- pretty much the same
- to evaporate water dogs pant to expose tongue
- Kangaroos lick fur to evaporate water
Physiological
- blood flow patterns (either core or skin surface) and dilation/constriction of blood vessels
- metabolic rate either inc/dec to produce heat by inc reactions
- evaporate water by perspiration
Structural
- fat, fur, hair, feathers (insulation)
- large surface area to volume ratio

Plants and animals transport dissolved nutrients and gases in a fluid medium

Students Learn to;

Identify the forms in which each of the following is carried in mammalian blood;
Carbon Dioxide: produced as a waste of respiration.
1. When its enters blood it can be converted to carbonic acid and then to hydrogen carbonate ions happening in the red blood cells and then dissolved in the plasma. (70% of CO2)
2. Bind to haemoglobin creating carbaminohaemoglobin (23% of CO2)
3. Dissolved directly into plasma (7%)

Oxygen: needed for respiration, it is transported on haemoglobin which has a high affinity with it to create oxyhaemoglobin.

Water: as itself in plasma as it is solvent in it, makes up about 60% of blood volume

Salts: transported directly dissolved in plasma as ions like sodium, magnesium, iron and zinc

Lipids: digested lipids are changed into triglyceride in the lining of the small intestine and transported as chylomicrons which are clusters of triglycerides, phospholipids and cholesterol, wrapped in a coat protein. They are released in the lymph and eventually released into veins and transported as part of the plasma.

Nitrogenous Wastes: ammonia is changed into urea and dissolved in the plasma

Other products of digestion: including amino acids, sugars, glycerol and vitamins which are mainly water soluble and transported dissolved in the plasma.

Explain the adaptive advantage of haemoglobin
- Haemoglobin increases the oxygen carrying capacity of blood by 100 times, this is mainly due to its high oxygen carrying capacity and it has a high affinity with oxygen.

Compare the structure of Arteries, capillaries and veins in relation to their function
Arteries: Arteries have a thick, elastic wall structure allowing expansion and recoiling to withstand pressure from heart pushing blood. It carries oxygenated blood in large quantities away from the heart.
Veins: Veins have a wide diameter vessel and are less elastic and muscular as arteries as there is less need to withstand pressure however they do contain valves to carry the blood up and to ensure it does not go backwards. They carry deoxygenated blood back to the heart.
Capillaries: capillaries provide a large surface area around tissue cells for efficient exchange of materials, they have the smallest diameter of the three with a one-cell thick wall to provide least resistance for exchange.

Describe the main changes in the chemical composition of the blood as it moves around the body and identify tissues in which these changes occur
Lungs: oxygenates / deoxygenates – same with CO2
Kidneys:osmo-regulation as well as the removal of nitrogenous wastes such as urea
Liver: the process of deamination turns glucose into glycogen then to urea, as it is unable to be stored.
Glands:release hormones to carry out specific function in the body, eg the Adrenal gland secretes ADH for kidneys.
Villi of small intestine: absorbs amino acids and glucose through the digestive walls to be taken to body cells

Outline the need for oxygen in living cells and explain why removal of carbon dioxide from cells is essential
- all organisms need oxygen for muscle movement, respiration results in CO2 production. When the CO2 dissolves in water it forms carbonic acid which over time will alter the pH of the blood to be more acidic, hence the need for its removal due to homeostasis.

Describe current theories about processes responsible for the movement of materials through plants in xylem and phloem tissue
Xylem – Theory: Cohesion, adhesion and transpiration (CAT)
- Xylem is a one-way water transport vessel made of dead tissue to facilitate passive movement of material.
- Transpiration: the evaporation of water from the leaves creates a suction, or transpiration pull up the xylem. Water is drawn up to replace this loss with the low concentration in the roots allow diffusion of the water in.
- Cohesion: water molecules tend to bind together, forming a continuous column up the xylem which replaces any loss.
- Adhesion: water molecules stick the sides of the xylem tubes (cellulose walls), pulling the water up the tubes
- The movement of water through narrow tubes is known as capillarity caused by the two forces of Cohesion/adhesion.

Phloem – Theory: Pressure flow theory
- Phloem is a transporter of organic molecules such as sugars, amino acids and hormones using translocation anywhere in the plant where there is a need for such material.
- Sugars are made in the leaves, which through active transport is transported into the phloem. This creates osmotic pressure because due to osmosis, inside the phloem will have less water concentration. This pushes the sugars anywhere along the phloem until it reaches a place of low osmotic pressure (where the sugar is needed) where active transport moves the sugars over to where it is needed, followed by the water due to laws of osmosis.

Students

Perform a first-hand investigation to demonstrate the effect of dissolved carbon dioxide on the pH of water
- 5 test tubes filled with 30ml of water, us a straw, blow into each for increasing amounts of time and use universal indicator to show pH.

Perform a first-hand investigation using the light microscope and prepared slides to gather information to estimate the size of red and white blood cells and draw scaled diagrams of each
Red Blood Cells
- 6-9uhm
- Shaped like bi-concave disks
- function: transport of oxygen
- they have no nuclei, only live for 3 months, destroyed in the liver or spleen
- 5-6 million in every mL of blood, produced in bone marrow
White Blood cell
- 12-15uhm
- have an irregular shape but can change shape
- function: defend against disease
- 4-12 thousand per mL of blood, largest blood cell, have a nuclei, produced in the lymph glands

Analyse information from secondary sources to identify current technologies that allow measurement of oxygen saturation and carbon dioxide concentrations in blood and describe and explain the conditions under which these technologies are used
Pulse Oximeter
- Measures O2 levels, a peg-like device pinches on the end of your finger and measures the transmission of light through tissues. It measures the amount of oxygen in arterial blood. There is a large difference between red light absorption by haemoglobin compared to oxyhaemoglobin.
- It is used in many conditions as it is painless, easy to apply and quick to give results. Can be used as a general check up on O2 levels, it is used during surgeries to monitor patients under anaesthesia. It is also used to monitor premature babies that are in neo-natal wards.
Arterial Blood Gas (ABG) Analysis
- measures O2 and Co2 levels using electrochemical methods measuring partial pressure (or concentration) of O2 and CO2 in the blood, measuring the saturation of oxygen (amount of O2 combined to haemoglobin compared to the maximum) then it measures the levels of bicarbonate and pH (to show Co2 levels). This analysis evaluates how effectively the lungs are delivering oxygen and removing carbon dioxide.
- it is used when there are signs of dangerously low oxygen or high CO2 levels, helps for diagnosing as well as monitoring patients under anaesthesia, in intensive care, premature babies or those in accident or emergency facilities. It is very accessible, a man in a coma can have their blood gases regularly monitored.

Analyse information from secondary sources to identify the products extracted from donated blood and discuss the uses of these products
WHOLE BLOOD: tested for transmissible disease and then can be used directly in case of an emergency.
Centrifugal separation of whole blood
RED BLOOD CELLS: red cell concentrates are used when patients need the oxygen carrying capacity of red bloods cells
WHITE BLOOD CELLS: white cell concentrates are used for patients who have a serious bacterial infection or a low white cell count, they help fight infections
PLASMA: used as Fresh Frozen Plasma (FFP) to quickly increase blood proteins or is further processed
Centrifugal Separation of plasma
PLATELETS: platelet concentrates are used to control bleeding or problems with platelet function.
Centrifugal separation THEN rapid freeze and thaw of plasma
CRYOPRECIPITATE: contains clotting factors and is most commonly used in the treatment of massive bleeding
CRYOSUPERNATE: further processed to make;
INTRAGAM: boosts the immune system after bone marrow transplants
HYPER IMMUNOGLOBULIN: used for protection against chicken pox, tetanus, hep B
NORMAL IMMUNOGLOBULIN: used to prevent Hep A
ANTI D: used to control rhesus disease in newborn babies

Analyse and present information from secondary sources to report on progress in the production of artificial blood and use available evidence to propose reasons why such research is needed
- Perflurocarbons: synthetic and inert. A powerful greenhouse gas emitted during the production of aluminium.
- Advantages: no cross-matching for blood type needed in emergencies / no diseases (compared to donated blood) / long shelf life (1-3 yrs) / doesn’t trigger rejection
- Disadvantages: haemoglobin isn’t attached to a red blood cell so it is ‘free-floating’ in the solution. This then goes between the cells, mops up nitric acid and causes eventual capillary collapse / release O2 in arteries instead of capillaries / can’t replicate immune function / can’t replicate clotting / needs to be mixed with other materials before mixing in with blood stream.
- disadvantages will be resolved as more research is done.

Choose equipment or resources to perform a first-hand investigation to gather first-hand data to draw transverse and longitudinal sections of phloem and xylem tissue
- Longitudinal: side-on view
- Transverse: birds-eye view
- Phloem: sieve cells surrounded by companion cells, nuclei present, sieve plates connect sieve tubes
- Xylem: Thick walls, lignified rings or spirals, no nucleus

Plants and animals regulate the concentration of gases, water and waste products of metabolism in cells and in interstitial fluid

Students Learn to;

Explain why the concentration of water in cells should be maintained within a narrow range for optimal function
- Water is essential for life, it makes up 70-90% of living things
- water is solvent of all metabolic reactions in living cells and sometimes directly takes part in it
- cells are isotonic; there water concentration is generally the same as outside the cell
- too much water (burst) too little (dehydration - death)
- for homeostasis / proper functioning of cells due to enzyme efficiency