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Title: HSC Biology - Maintaining a Balance
Description: HSC Biology notes These notes are to help those that are doing the HSC Biology course. Clear and easy to understand diagrams and images are included It covers the entire module of 'Maintaining a Balance' with easy dot point to dot point explanations. These notes are based off the syllabus as of 2016
Description: HSC Biology notes These notes are to help those that are doing the HSC Biology course. Clear and easy to understand diagrams and images are included It covers the entire module of 'Maintaining a Balance' with easy dot point to dot point explanations. These notes are based off the syllabus as of 2016
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Syllabus Notes- Maintaining a Balance
1
...
1
...
● All metabolic reactions in living cells are controlled by enzymes
...
All
metabolic reactions are controlled by enzymes
...
Catabolic Breaking down complex organic compounds to simpler ones
...
The enzymes can be reused in subsequent reactions
...
● Enzymes are globular proteins
...
● Their effective functioning relies on their shape
...
An enzyme fits together with its substrate molecule on a
surface called the active site
...
●
Induced fit model The enzyme changes it shape slightly to fit more tightly around the
substrate
...
3 Identify the pH as a way of describing the acidity of a substance
...
● 0 6 pH means the substance is acid
...
814 pH means the substance
is basic
...
4 Explain why the maintenance of a constant internal environment is important for optimal
metabolic efficiency
...
temperature and
pH
...
5 Describe homeostasis as the process by which organisms maintain a relatively stable
environment
...
● Living organisms must have mechanisms in place to enable them to function
independently to external changes
...
6 Explain that homeostasis consists of two stages:
detecting changes from the stable state
counteracting changes from the stable state
Detecting Changes:
●
Sensory cells called receptors detect stimuli and sends the signal to the control centre of
the organism
...
Counteracting Changes:
●
A response occurs counteracting the change, thus maintaining a stable internal
environment
...
7 Outline the role of the nervous system in detecting and responding to environmental
changes
...
Detecting the change in external and internal environments
...
Information is sent to the organism’s control centre (brain)
...
The control centre processes the received information and generates a response to
maintain homeostasis
...
●
Stimulus response pathway:
Stimuli → Receptors → CNS → Effectors → Response
Receptors: Sensory cells that detect stimuli
...
Effectors: Effectors put the response into action
...
Thermoreceptors detect change in temperature
...
Mechanoreceptors detect changes in pressure
...
Coordination:
●
Central Nervous System (CNS) Process information, analyse, then initiate an
appropriate response
...
1
...
9 Identify the broad range of temperatures over which life is found compared with the narrow
limits for individual species
...
However, there are organisms that can survive low temperatures of 70oC and high
temperatures of 200oC
...
10 Compare responses of named Australian ectothermic and endothermic organisms to
changes in the ambient temperature and explain how these responses assist temperature
regulation
...
Endotherm Organisms which are able to regulate their internal temperature through
their internal metabolism
...
Seek water radiation of cooler air
...
Reduce movement Less heat generated by
muscles
...
Sun Baking Increases body temperature
by absorption of solar radiation
...
Decrease in external temperature
Endotherm: Red Kangaroo/ Bilby/ Spinifex Hopping Mouse
Increase in external temperature
Decrease in external temperature
Seek shade reduce exposure to solar
radiation
...
Seek water evaporative cooling
Insulation Erect hairs to trap heat
...
Puts arteries closer to the skin surface which
makes it easier to radiate heat out
...
Red Kangaroo licks its paws to increase
evaporation rate
...
Hibernation minimizes energy
expenditure during the colder months
...
1
...
●
Turgor Response (Wilting) Reduce exposure of surface area to the sun by reducing
pressure in the vacuole of cells
...
Cold Temperatures:
●
Organic Antifreeze The plant produces organic compounds that act as antifreeze
...
●
Dormancy Deciduous trees lose their leaves to slow down metabolism and minimize
energy expenditure
...
2
...
2
...
● Some bind to haemoglobin as carbaminohaemoglobin (23%)
...
Oxygen:
● Binds to haemoglobin as oxyhaemoglobin (98%)
...
Lipids:
● Carried with phospholipids and cholesterol in a protein coated package called
chylomicron in the lymphatic system
...
Salts:
● Dissolved in plasma as ions
...
2 Explain the adaptive advantage of haemoglobin
Structure of Haemoglobin:
● Haemoglobin is a protein made up of four polypeptide chains (globin) each bound to an
iron group (haem)
...
(Increases the oxygen carrying capacity of blood)
...
3) Bohr Effect:
Haemoglobin loses affinity to oxygen in areas of low pH
...
2
...
Its three layers include the endothelium
as a lining, muscle tissue and connective tissue
...
● Due to the thick muscular tissue, arteries have a small lumen
...
It has three layers which include the endothelium
as a lining, muscle tissue and connective tissue
...
● Veins have a large lumen to maximise the blood flow as pressure in the veins are low
...
Capillaries:
● The function of capillaries is to exchange substances with cells and the bloodstream
such as, oxygen to respiring cells and the removal of nitrogenous wastes and carbon
dioxide
...
2
...
● The lungs take in oxygen and remove carbon dioxide
...
● Organs and cells require oxygen to respire and produce carbon dioxide as a waste
product
...
● The Liver produces nitrogenous wastes as a result of deamination (the breaking down of
amino acids)
...
● Kidneys filter out and remove the nitrogenous wastes from the body
...
● Digestive products are absorbed in the small intestines
...
2
...
This
process requires oxygen
...
The removal of Carbon Dioxide:
● When carbon dioxide dissolves in water, it becomes carbonic acid
...
Enzymes function at a limited
range of pH therefore a build up in carbonic acid would interrupt with metabolic
processes and enzyme function
...
8 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:
● Pulse oximeters are a noninvasive device that only measure oxygen saturation in the
blood
...
During surgery, to ensure the patient is receiving enough oxygen
...
Blood Gas Analysers:
● Blood gas analysers electrochemically analyse samples of arterial blood to measure gas
levels
...
● Blood Gas analysers are used for:
Testing for severe breathing problems
...
Measuring the blood gases in intensive care units, such as babies
...
9 Analyse information from secondary sources to identify the products extracted from donated
blood and discuss the uses of these products
Products extracted from Whole Blood
Use
Red Blood Cells
●
Red blood cells transport oxygen and
carbon dioxide in the body
...
Used to treat patients with
anaemia
...
●
WBC’s are used to help people with a
compromised immunity
(immunocompromised) to fight off
diseases by bolstering their immune
system
...
Can also
thicken blood
...
eg
...
Also used to treat bleeding disorders,
such as patients with leukemia who
do not produce bone marrow
...
They are used to
treat people from severe bleeding
...
●
Albumin: Albumin is a transport
protein in the blood
...
2
...
● There are mainly two types of artificial blood substitutes:
Haemoglobin based substitutes :
Modified haemoglobin
...
Polyheme, made from modified human haemoglobin
...
Perfluorocarbon based substitutes:
Chemical compounds composed of carbon and fluorine which are able to transport
oxygen like haemoglobin
...
Circulation life is 1224 hours
...
These replace
lost plasma and expands the blood to increase oxygen delivery
...
Can be stored for years
...
Can be deployed in areas of isolation eg
...
● Disease free:
Artificial blood is disease free and do not need screening which saves resources
...
HIV in Africa
...
●
No need for cross compatibility:
Artificial blood is compatible for everyone unlike regular blood
...
2
...
● Phloem: Translocates organic products and sugars
...
Transpiration Stream Theory:
Water is absorbed into the roots by osmosis
...
They are also bound to the xylem
walls through adhesion
...
Source to Sink Theory:
Explains how organic products and sugars are transported in plants
...
2) Osmosis occurs due to the high concentration of solute and water from the xylem moves
into the phloem and dissolves the sugars
...
3
...
1 Explain the why the concentration of water in cells should be maintained within a narrow
range for optimal function
● Water is the solvent for metabolic reactions in living cells without water,
metabolic reactions could never function
...
Decreasing
the volume of water will concentrate the substrate
...
Temperature It takes a lot of energy to increase the temperature of water
...
3
...
Carbonic acid lowers the pH
of water which comprises enzymes function as they require an optimum pH range
...
● Nitrogenous wastes are toxic to cells as they can denature enzymes or attack the cell
structure directly
...
3
...
● The kidney is the body’s filtration system and is responsible for removing nitrogenous
wastes from the blood
...
● Osmoregulation is the major function of the kidneys for fish, as they excrete most of their
nitrogenous wastes from their gills
...
4 Explain why the processes of diffusion and osmosis are inadequate in removing dissolved
nitrogenous wastes
● Diffusion and osmosis are both passive transport and rely on Brownian Motion; random
movement of particles
...
● The rate of diffusion and osmosis also slows down as it reaches equilibrium
...
3
...
● Active transport is the transport of substances against the concentration gradient, with
the expenditure of ATP in the process
...
● All reabsorption and secretion activity that occurs with the kidney is due to active
transport
...
6 Explain how the processes of filtration and reabsorption in the mammalian nephron regulate
the body fluid composition
The Nephron:
Region of Nephron
Substances Transported
Type of Transportation
Glomerulus
Glucose, amino acids, salts,
bicarbonate, urea, uric acid,
potassium, calcium
Passive transport filtration
Proximal Convoluted Tubule
Glucose, amino acids,
bicarbonate, salt
Drugs and toxins
Active transport
reabsorption
Passive transport osmosis
Active transport secretion
Descending Loop of Henle
Water
Passive transport osmosis
Ascending Loop of Henle
Salts, potassium
Active transport
reabsorption
Distal Convoluted Tubule
Salts, potassium
Hydrogen ions, potassium,
nitrogenous wastes
Active transport
reabsorption
Active transport secretion
Collecting Ducts
water
Passive transport osmosis
3
...
● Blood from the patient is pumped into the machine where a dialysate passively removes
nitrogenous wastes
...
The peritoneum (a thin membrane
that covers the organs) acts as a semi permeable membrane
...
Renal Dialysis
Structure
1 million nephrons which filter
blood
Haemodialysis attached to
machine with semi permeable
filters
...
9 Outline the role of Hormones, aldosterone and ADH (antidiuretic hormone), in the
regulation of water and salt levels in blood
Hormone
Location of
Production
Location of
Effect
Direct effect
Consequences
Aldosterone
Adrenal glands
Distal
Convoluted
Tubule
Increases active
salt
reabsorption;
decreased
active
potassium
reabsorption
and increased
passive water
reabsorption
...
Increases
plasma
osmolarity
...
increases blood
volume and
pressure
...
3
...
● This can be caused by the absence of the hormone Cortisol which stimulates the
adrenal glands to produce aldosterone
...
● Fludrocortisone: this replaces the aldosterone for those who can't manufacture
aldosterone at all
...
11 Analyse information from secondary sources to compare and explain the differences in
urine concentration of terrestrial mammals, marine fish and freshwater fish
Organism
Vol
...
of Urine
Nitrogenous waste
excreted
Mammal
Small
Concentrated
Urea
Marine Fish
Small
Concentrated
Ammonia or urea
Freshwater Fish
Large
Dilute
Ammonia
Insects
Small
Concentrated paste
Uric Acid
3
...
● These tubules collect water and uric acid
...
● Since uric acid is insoluble in water, it can be excreted without the loss of water
...
● Because they must conserve water, they excrete small volumes of highly concentrated
urine
...
● Organism that excrete urine are referred to as ureotelic
...
● This results in water constantly moving out of the fish through osmosis resulting in water
loss
...
Freshwater Fish:
● Freshwater fish live in a hypotonic environment; there is less salt in the surrounding
water than in their own cells
...
● Since conserving water is not a problem for freshwater fish, it produces large amounts of
diluted ammonia which is excreted constantly
...
13 Define enantiostasis as the maintenance of metabolic and physiological functions in
response to variations in the environment and discuss its importance to estuarine organisms in
maintaining appropriate salt concentrations
● Enantiostasis is the maintenance of metabolic and physiological function in
response to variations in the environment
...
Organisms which deal with fluctuations in salt concentration are referred to as
euryhaline
...
Examples of osmoconformers are: Saltbush, Grey Mangroves, fish
...
Examples of osmoconformers are: Blue Crabs, most
marine invertebrates
...
3
...
Salt marsh plants (Sarcocornia quinqueflora, Sporobolus virginicus):
● Accumulates salt in the swollen leaf bases which fall off, removing excess salt
...
Grey Mangrove (Avicennia marina):
● Has special salt glands which excrete salt onto the leaves which is washed away
...
● Can store salt in leaves which then drop
...
15 Describe adaptations of a range of terrestrial Australian plants that assist in minimising
water loss
Australian plants have adaptations to minimise water loss through stomata:
● Closing stomata: Australian plants such as Eucalypts and the Spiny fanflower
(Eremophila spinescens) are able to control the opening of their stomata
...
● Sunken stomata: by having a sunken stomata, a pocket of air is created, where less
evaporation occurs
...
g
...
● Stomatal distribution: by having more stomata on the underside of the leaves, the
sun’s heat hits the other side
...
Acacias also have reduced size leaves
...
Some plants can even alter the orientation of their leaf
as the day progresses
...
It also creates a microclimate which can cause less evaporation
...
Banksia
● Waxy cuticle: a thick waxy cuticle prevents escape of water, and also acts as a
reflective surface for sunlight to be reflected off
...
Saltbush, Banksia
●
Leaf dropping: plants may drop their leaves because heat would cause severe water
loss, making it safer to have no leaves at all
...
River Gum
...
eg
...
Title: HSC Biology - Maintaining a Balance
Description: HSC Biology notes These notes are to help those that are doing the HSC Biology course. Clear and easy to understand diagrams and images are included It covers the entire module of 'Maintaining a Balance' with easy dot point to dot point explanations. These notes are based off the syllabus as of 2016
Description: HSC Biology notes These notes are to help those that are doing the HSC Biology course. Clear and easy to understand diagrams and images are included It covers the entire module of 'Maintaining a Balance' with easy dot point to dot point explanations. These notes are based off the syllabus as of 2016