HSC Biology Marathon 2017 (1 Viewer)

pikachu975

Premium Member
Joined
May 31, 2015
Messages
2,739
Location
NSW
Gender
Male
HSC
2017
Haven't seen many people that do bio on this forum but anyway post questions.

First question:
(This is just a made up question)
Describe the mechanism of feedback with the use of ONE positive feedback mechanism in humans. (3 marks)


Hint:
2 marks for the description of feedback and one for the example
 

Green Yoda

Hi Φ
Joined
Mar 28, 2015
Messages
2,859
Gender
Male
HSC
2017
A feedback mechanism is a process of altering the stimulus by bringing up the change through the effectors which then create a response or a feedback. These feedbacks can be either positive which enhance the effects of the original stimulus, or they can be negative which reduce the affect of the original stimulus. An example of a positive feedback is the release of Oxytocin from by contractions during child birth causing more contractions.
 

pikachu975

Premium Member
Joined
May 31, 2015
Messages
2,739
Location
NSW
Gender
Male
HSC
2017
The answer is D
The reason why it's not A) is because it is the Enzyme. B) Is the whole process C) The product

-
What are the role of Enzymes? (1 mark)
Enzymes are biological catalysts that speed up metabolic processes in cells and organisms. They are responsible for assisting with homeostasis in an organism in maintaining a stable state despite environmental changes.
 

Green Yoda

Hi Φ
Joined
Mar 28, 2015
Messages
2,859
Gender
Male
HSC
2017
Enzymes are biological catalysts which increase the the rate of chemical reactions in living organisms and decrease the activation energy. This makes the metabolism in organisms efficient.
 

Green Yoda

Hi Φ
Joined
Mar 28, 2015
Messages
2,859
Gender
Male
HSC
2017
The answer is D
The reason why it's not A) is because it is the Enzyme. B) Is the whole process C) The product

-
What are the role of Enzymes? (1 mark)
I thought C was the substrate?
 

pikachu975

Premium Member
Joined
May 31, 2015
Messages
2,739
Location
NSW
Gender
Male
HSC
2017
Name one Australian endotherm and one Australian ectotherm and describe how they respond to temperature changes and regulate their own body temperature. (8 marks)

You don't need to write out the whole response, just give an outline:
e.g. Two animals - animal 1, animal 2
Animal 1 - adaptation, adaptation, adaptation

etc
 

Green Yoda

Hi Φ
Joined
Mar 28, 2015
Messages
2,859
Gender
Male
HSC
2017
^Haven't got up that that yet..will try to learn it tomorrow and answer it
 

pikachu975

Premium Member
Joined
May 31, 2015
Messages
2,739
Location
NSW
Gender
Male
HSC
2017
^Haven't got up that that yet..will try to learn it tomorrow and answer it
Well just for reference, the examples I've got are kangaroos for endotherm and frill neck lizard for ectotherm.
 

Green Yoda

Hi Φ
Joined
Mar 28, 2015
Messages
2,859
Gender
Male
HSC
2017
Name one Australian endotherm and one Australian ectotherm and describe how they respond to temperature changes and regulate their own body temperature. (8 marks)

You don't need to write out the whole response, just give an outline:
e.g. Two animals - animal 1, animal 2
Animal 1 - adaptation, adaptation, adaptation

etc
Endotherms are organisms that regulate their own internal temperature and are independent from the ambient temperature. Ectotherm organisms who's internal temperature is dependent on the ambient temperature. An Endotherm regulates the body temperature through the process of homoeostasis while an Ectotherm needs to seek other methods. They both have many physiological and behavioural adaptions which help them maintain this temperature. An example of an Endothermic organism is a Bare Nosed Wombats. These organisms have many behavioural adaptions to respond to increasing temperature in their body such as; burrowing underground to avoid heat, active at night instead of the day to avoid heat from the sun, and soaking themselves with water to cool down. They also have many physiological adaptions to cool down such as; lowering the metabolism to conserve energy and heat and vasodilation. To respond to decreasing temperatures in their body they also have many behavioural adaptions such as; burrowing underground to avoid the cold, and many physiological adaptions such as; vasoconstriction. An example of an Exothermic organism is the Australian Barking Gecko. Ectotherms mainly have behavioural adaptions to temperature changes. These organism have many behavioural adaptions to respond to increasing temperature in their body such as; lifting their body off the hot ground to reduce surface area exposed to the ground, seeks shade, and becomes active at night. To respond to decreasing temperatures in their body they also have many behavioural adaptions such as; basking in the sun to absorb heat and flattening their body on the ground to increase surface are to get more heat from the ground and the sun.
 

Green Yoda

Hi Φ
Joined
Mar 28, 2015
Messages
2,859
Gender
Male
HSC
2017
Explain why importance of homeostasis is important for optimal metabolic efficiency? (4 marks)
 

pikachu975

Premium Member
Joined
May 31, 2015
Messages
2,739
Location
NSW
Gender
Male
HSC
2017
Explain why importance of homeostasis is important for optimal metabolic efficiency? (4 marks)
Homeostasis is the maintaining of a relatively stable internal environment within an organism. It is essential for metabolic efficiency because metabolic processes are catalysed by enzymes, which function optimally in narrow environmental conditions and are vastly affected by factors such as temperature, pH and substrate concentration. Each enzyme has its own optimal temperature range, and if the temperature gets too high, reactions can occur too rapidly and lead to the polypeptide chains to break, denaturing and killing the enzyme. If the temperatures get too low, the enzyme can freeze and reactions occur much slower, meaning metabolic efficiency is at a low level. Furthermore, the pH of an area containing enzymes can affect it because if it gets too acidic or too basic, then the enzyme can get denatured and stop functioning, hence slowing down metabolic processes. The substrate concentration is essential for metabolic efficiency because the more substrates there are, then the more chance an enzyme will react with one. If every enzyme is working at maximum capacity, then metabolism is occurring at its maximum potential. All of these factors show the importance of homeostasis because if a constant internal environment is not maintained, then enzymes will not run efficiently and can even die, leading to a low metabolic efficiency.
 

pikachu975

Premium Member
Joined
May 31, 2015
Messages
2,739
Location
NSW
Gender
Male
HSC
2017
Endotherms are organisms that regulate their own internal temperature and are independent from the ambient temperature. Ectotherm organisms who's internal temperature is dependent on the ambient temperature. An Endotherm regulates the body temperature through the process of homoeostasis while an Ectotherm needs to seek other methods. They both have many physiological and behavioural adaptions which help them maintain this temperature. An example of an Endothermic organism is a Bare Nosed Wombats. These organisms have many behavioural adaptions to respond to increasing temperature in their body such as; burrowing underground to avoid heat, active at night instead of the day to avoid heat from the sun, and soaking themselves with water to cool down. They also have many physiological adaptions to cool down such as; lowering the metabolism to conserve energy and heat and vasodilation. To respond to decreasing temperatures in their body they also have many behavioural adaptions such as; burrowing underground to avoid the cold, and many physiological adaptions such as; vasoconstriction. An example of an Exothermic organism is the Australian Barking Gecko. Ectotherms mainly have behavioural adaptions to temperature changes. These organism have many behavioural adaptions to respond to increasing temperature in their body such as; lifting their body off the hot ground to reduce surface area exposed to the ground, seeks shade, and becomes active at night. To respond to decreasing temperatures in their body they also have many behavioural adaptions such as; basking in the sun to absorb heat and flattening their body on the ground to increase surface are to get more heat from the ground and the sun.
Also maybe a concluding sentence to sum it all up could help. E.g. "Therefore, it is evident that both endotherms and ectotherms have their respective behavioural and physiological adaptations in responding to changes in temperature and regulating their own body heat". or something to finish it off.
 

Maancis

New Member
Joined
Apr 14, 2016
Messages
27
Gender
Female
HSC
2017
Haven't seen many people that do bio on this forum but anyway post questions.

First question:
(This is just a made up question)
Describe the mechanism of feedback with the use of ONE positive feedback mechanism in humans. (3 marks)


Hint:
2 marks for the description of feedback and one for the example
I'm pretty sure we only need to know negative feedback
 

Incandescence

New Member
Joined
Feb 28, 2016
Messages
2
Gender
Undisclosed
HSC
2017
All questions so far seem to have been answered, so I'll throw another question in, if no one minds:

Describe the main changes in blood composition as it travels around the body and identify the tissues in which these changes occur. (5 marks ?) Not sure how much this would be worth o:
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top