HSC Biology|Complete Questions with A+ Graded Answers
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Course
HSC
Institution
HSC
HSC Biology|Complete Questions with A+ Graded Answers
The process by which an organism maintains a constantly stable internal environment. Two stages: Detecting for changes to the stable state and correcting for these changes.
Homeostasis
All chemical processes occurring within an organism...
HSC Biology|Complete Questions with A+ Graded
Answers
The process by which an organism maintains a constantly stable internal environment. Two stages:
Detecting for changes to the stable state and correcting for these changes.
Homeostasis
All chemical processes occurring within an organism in order to sustain life.
Metabolism
An enzyme is a large protein molecule that acts as a biological catalyst for one specific molecule.
What is an enzyme?
Enzymes have an active site which is a surface chemical reactions can occur on.
How do enzymes work?
Every enzyme has a specific active site shape. Certain substrates fit like a key in the active site and can
then undergo a chemical reaction.
Describe the lock and key model.
Enzyme active sites do not have a specific shape, the active site wraps around a substrate.
Describe the induced fit model.
A molecule upon which an enzyme acts.
What is a substrate in relation to enzymes?
Rennin - Found in the stomach of mammals, necessary for the coagulation of milk for digestion.
Rennin works best at a temperature of around 37C and pH of 0.8.
Example of an enzyme.
High temperatures, pH outside of safe parameters.
What causes an enzyme to denature?
Photoreceptor
Thermoreceptor
Mechanoreceptor
Chemoreceptor
Name the receptors.
,Light
Temp
Sound/touch/pressure
Chemicals
In a negative feedback system, the response of the effector negates the stimuli initially described by
the receptor. Example: Thermoregulation
Describe a negative feedback system
In a positive feedback system, the response of the effector compliments the stimuli initially picked up
by the receptor. Example: Release of oxytocin during childbirth.
Describe a positie feedback system
Neurospora Crassa
Scientific name of bread mould
Drosophilla Melanogaster
Scientific name of fruit fly
Echinoidea
Scientific name of sea urchin
Brachystola Magna
Scientific name of grasshopper
Pisum Sativum
Scientific name of pea plant
An ectotherm is an organism that relies of environmental factors to thermoregulate.
Example: Central Bearded Dragon
What is an ectotherm?
An endotherm is an organism that can self-thermoregulate regardless of environmental factors. (To
an extent)
Example: The Greater Bilby
What is an endotherm?
, Macrotis Lagotis
Scientific name of Greater Bilby?
Pogona Vitticeps
Scientific name of Central Bearded Dragon?
Migration
Basking
Hibernation
Name three behavioural responses to change in temperature.
Insulation
Sweating
Control of blood flow
Name three physiological responses to change in temperature.
The Short-Beaked Echidna enters a hibernation-like brief period of Torpor.
Name an Australian organism that hibernates
Plants alter their growth rate.
Growth normally occurs between 5-45C.
How do plants respond to temperature change?
-Leaves grow vertically to minimise sun exposure
-Reflective leaf surfaces reduce heating of leaf
-Excess transpiration to cool the plant (Reduced in arid climates)
Describe some ways a plant might respond to heat
1. Transport of respiratory gases, nutrients, water, waste.
2. Blood clotting
3. Defence against disease (antibodies and phagocytes/lymphocytes)
4. Temperature regulation, control of how close to the skin surface blood flows.
Name four functions of the mammalian circulatory system
Plasma is straw-yellow, sticky, salty and about 90% water. It contains ionic salts and plasma proteins,
which assist in pH balance of the blood.
Describe plasma and %
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