MIAB CRAP

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 t

- Without enzymes the metabolism would be

be too slow to support life.

- Enzymes control

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

- Provides an alternative pathway for a

chemical reaction to occur.

- Most enzymes made of

proteins

They are made of

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

The long chains of amino acids are

joined together by peptide bonds

- The shape allows it to

attach to reactant molecules

- The reactant is called the

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

- Most of the time the enzyme molecule is

larger protein molecule bigger than the substrate.

- The protein structure is related to

enzyme specificity.

- 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

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

the shape of the substrate material.

- 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 s

Specificity of enzymes

? 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 gener

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

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

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 enzym

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.

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 dec

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 organ

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.

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 mode

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.
- Mamm

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 o

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 envir

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,

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

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 sup

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 bod

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

- RED BLOOD CELLS (Erythrocytes):
� Size: 6-9 �m
� 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 bloo

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 bloo

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 pressur

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

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 enter

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

- 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

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

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 constan

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

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, ver

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 b

� 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 tubule

� 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 al

� 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 t

� 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 b

� 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 co

� 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

� 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 expenditur

� 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 halophyt

� 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

� 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