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Thread: HSC Biology Marathon 2015

  1. #101
    Exalted Member BlueGas's Avatar
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    Re: HSC Biology Marathon 2015

    HSC question: Explain the relationship between replication of DNA and evolution. 5 marks

    Don't look at sample answers, answer it from either your mind or your notes

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    Re: HSC Biology Marathon 2015

    Quote Originally Posted by astab View Post
    Substances that filter into the glomerulus must be small enough to filter through. They include urea, water, solutes, ions, amino acids and glucose. Essential metabolites (solutes, ions, amino acids and glucose) are reabsorbed. They are actively pumped back into the blood vessels at the descending loop of Henle and distal tubules. Water inadvertently follows this change in solute concentration and moves into the blood vessel by osmosis (to maintain the concentration gradient at the blood vessel).
    Aren't the metabolites pumped back into the blood vessels at the ascending loop of henle?

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    Re: HSC Biology Marathon 2015

    Quote Originally Posted by astab View Post
    Why do freshwater fish actively absorb salts if they gain a lot of water by osmosis? Wouldn't salt absorption attract even more water, causing it to burst?
    They absorb salts because there is very little salt in their environment. Yes you're correct this salt concentration would attract even more water via osmosis, however this is why freshwater fish produce copious amounts of dilute urine to counteract this.

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    Re: HSC Biology Marathon 2015

    Quote Originally Posted by Fiction View Post
    Nw

    Evaluate the following statement:
    Evolution is both supported and not supported by paleontological evidence. (5 marks)
    Paleontology is the study of fossils and extinct life form. These fossil records show the history of life on earth. For example the oldest fossil of cyanobacteria at 3.5mya and earliest reptile 350mya. They show the change over a long period of time (Darwin's Gradualism) between organisms and how they have adapted to survive under "selection pressures" that may have forced them out of their niche. Charles Darwin used paleontological evidence to describe how short neck giraffes died out as their short necks made them unable to reach tall trees for leaves, while the long-neck giraffe could and was "fitter" to survive. However it is also no supported as "punctuated equilibrium" proposes that, instead of gradual change, there have been periods of rapid evolution followed by long periods of stability, or equilibrium. This ultimately conflicts the theory of Evolution.

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    Re: HSC Biology Marathon 2015

    A new non-infectious disease has been discovered in people in some aged care homes.
    Outline at least FOUR features of an epidemiological study that could be used to

    identify the cause of this disease.

  6. #106
    Exalted Member BlueGas's Avatar
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    Re: HSC Biology Marathon 2015

    Quote Originally Posted by kevinsta View Post
    A new non-infectious disease has been discovered in people in some aged care homes.
    Outline at least FOUR features of an epidemiological study that could be used to

    identify the cause of this disease.
    Yay, this thread is alive!

    1. Through analysis of statistics, it must demonstrate a significant link between the cause and the disease
    2. The study must be done on a large range of subjects, in terms of age, sex, race, occupation, and geographical postion
    3. The results should be consistent and persist over time
    4. The study should be repeatable by other investigators at different time, and different places, using different methods

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    Re: HSC Biology Marathon 2015

    Quote Originally Posted by kevinsta View Post
    A new non-infectious disease has been discovered in people in some aged care homes.
    Outline at least FOUR features of an epidemiological study that could be used to

    identify the cause of this disease.
    1. A large sample size is needed and so information should be collected from other aged care homes nearby.
    2. The information collected should comprise of people having a broad range of lifestyle activities, ethnicity and diet
    3. A control group can be used which can be established by collecting data from some aged care groups that are away from the local area to determine whether the disease has an environmental cause and again the data collected should have a broad range of info such as ethnicity, lifestyle activities (e.g. smoking, alcohol consumption), occupation, etc.
    4. The gathered information should be collected and organised so that analysis can be performed to determine the relationship between one feature and the cause of the disease while having other factors remaining constant (e.g. relationship b/w Smoking and the cause of the disease eith other favtors such as alcohol consumption remaining constant)

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    Re: HSC Biology Marathon 2015

    Quote Originally Posted by BlueGas View Post
    HSC question: Explain the relationship between replication of DNA and evolution. 5 marks

    Don't look at sample answers, answer it from either your mind or your notes
    The replication of DNA is a mechanism that allows evolution can occur. Through the replication of DNA such as in mitosis, somatic cells in living organisms can be replicated so that they are similar to the ones that they (new cells) are replacing. This ensures the survival of the species and hence allows them to pass on favourable characteristics to their offspring as they reproduce. Also, DNA replication in meiosis allows the copying of DNA so that the similar DNA coding is passed onto their offspring, allowing the offspring to have the same genetic information ad their parents. This would be advantageous if the genes are favourable in the environment that the offspring is situated within. Furthermore, it is also through the process of DNA replication whereby mutation can occurs which can give rise to new alleles and hence expanding the gene pool of the population and new phenotypic features to the species of the population. If these alleles are favourable, the new and superior offspring would reproduce more successfully and pass on their genetic information to their offspring through the process of DNA replication in meiosis and through DNA replication in mitosis that allows the superior offspring to survive and cope with its environment. Hence it is through DNA replication whereby individual species can survive as well as pass on their favourable (and not favourable) characteristics to their offspring to ensure that evolution can occur (e.g. through natural selection). Hence there is a definite link between replication of DNA and evolution.

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    Re: HSC Biology Marathon 2015

    a) Outline the use of hormone replacement therapy in people who cannot secrete adolsterone.
    b) Explain why the therapy is important for these people.

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    Re: HSC Biology Marathon 2015

    Using an example, describe how advances in technology have changed scientific thinking about evolutionary relationship.

  11. #111
    Exalted Member BlueGas's Avatar
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    Re: HSC Biology Marathon 2015

    Quote Originally Posted by kevinsta View Post
    Using an example, describe how advances in technology have changed scientific thinking about evolutionary relationship.
    Can someone answer this question ASAP? I really need to know the answer for this.

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    Re: HSC Biology Marathon 2015

    Quote Originally Posted by BlueGas View Post
    Can someone answer this question ASAP? I really need to know the answer for this.
    Our scientific thinking about evolutionary relationships between animals has changed dramatically as a result of advances in technology. For example technologies such as biochemical analysis uses DNA-DNA hybridisation to compare amino-acid chains between other organisms. From previous knowledge we believed that humans where closely related to the rhesus monkeys, and that gorillas and orangutans where closely related. However due to biochemical analysis it was revealed that humans shared 97% of the same DNA as orangutan, this was much higher than rhesus monkeys, meaning that humans are more closely related to orangutans and that they must have evolved from a common ancestor. This shows how advances in technology has changed our scientific thinking about evolutionary relationships.

    (sorry this came from the top of my head, probably not the greatest answer but I tried)

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    Re: HSC Biology Marathon 2015

    Quote Originally Posted by kevinsta View Post
    Our scientific thinking about evolutionary relationships between animals has changed dramatically as a result of advances in technology. For example technologies such as biochemical analysis uses DNA-DNA hybridisation to compare amino-acid chains between other organisms. From previous knowledge we believed that humans where closely related to the rhesus monkeys, and that gorillas and orangutans where closely related. However due to biochemical analysis it was revealed that humans shared 97% of the same DNA as orangutan, this was much higher than rhesus monkeys, meaning that humans are more closely related to orangutans and that they must have evolved from a common ancestor. This shows how advances in technology has changed our scientific thinking about evolutionary relationships.

    (sorry this came from the top of my head, probably not the greatest answer but I tried)
    It says advanceS so maybe need one more point?

  14. #114
    Exalted Member BlueGas's Avatar
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    Re: HSC Biology Marathon 2015

    Quote Originally Posted by DepressedPenguino View Post
    It says advanceS so maybe need one more point?
    Is this a HSC question? If so, I want to know what year so I can look at the sample answer.

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    Re: HSC Biology Marathon 2015

    Quote Originally Posted by BlueGas View Post
    Is this a HSC question? If so, I want to know what year so I can look at the sample answer.
    IDK but the Ahmad Shah revised and edited have a decent answer to this.

  16. #116
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    Re: HSC Biology Marathon 2015

    Quote Originally Posted by BOS Secret Service View Post
    IDK but the Ahmad Shah revised and edited have a decent answer to this.
    The answer is quite lengthy though.

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    Re: HSC Biology Marathon 2015

    Quote Originally Posted by kevinsta View Post
    Using an example, describe how advances in technology have changed scientific thinking about evolutionary relationship.
    Nah i think the hsc one only asks for ONE specifically

  18. #118
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    Re: HSC Biology Marathon 2015

    Quote Originally Posted by DepressedPenguino View Post
    Nah i think the hsc one only asks for ONE specifically
    What HSC year?

  19. #119
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    Re: HSC Biology Marathon 2015

    Quote Originally Posted by kevinsta View Post
    Using an example, describe how advances in technology have changed scientific thinking about evolutionary relationship.
    How many marks is this Q?

    ***

    Advances in technology, specifically in the field of biochemistry, such as amino-acid sequencing and DNA–DNA hybridization have changed our thinking about evolutionary relationships.

    Originally, scientists used paleontology and comparative anatomy to construct evolutionary links. For example, they originally thought Gorillas were related to humans the most through this type of evidence. However after advances in technology, amino-acid sequencing and DNA-DNA hybridization have since showed that chimpanzees are actually humans' most related species. Thus, scientists can now use biochemistry to study the organism on a molecular level when thinking about evolutionary relationships.
    2015 HSC: English Adv, Mathematics, Business Studies, Biology, Multimedia.

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  20. #120
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    Re: HSC Biology Marathon 2015

    Quote Originally Posted by DepressedPenguino View Post
    It says advanceS so maybe need one more point?
    Advance"S" could maybe just mean amino acid sequencing and DNA–DNA hybridization, there is also DNA sequencing.
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    Re: HSC Biology Marathon 2015

    BUMP lets get some more questions going

    "Outline the effect of aldosterone on the control of body fluids. "
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    Re: HSC Biology Marathon 2015

    Quote Originally Posted by Flop21 View Post
    BUMP lets get some more questions going

    "Outline the effect of aldosterone on the control of body fluids. "
    Aldosterone is a hormone which results in the control of body fluids in the kidney by acting on the distal tubes and collecting ducts of the nephron to increase the reabsorption of salt ions and hence water (by osmotic balance) back into the body. In blood containing high salt concentration, there are low levels of aldosterone as it is not needed. However, in blood of low salt concentration Aldosterone levels increase.
    Last edited by Mr_Kap; 22 Sep 2015 at 3:15 PM.

  23. #123
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    Re: HSC Biology Marathon 2015

    Quote Originally Posted by Mr_Kap View Post
    Aldosterone is a hormone which is produced in the adrenal gland, and is released when the concentration of salts and ions in the blood is low. Aldosterone results in the control of body fluids when it is released into the kidney and acts on the distal tubes and collecting ducts of the nephron increasing the reabsorption of salt ions and hence water back into the body.

    Can anyone help on this one?
    Aldosterones major function is to regulate blood volume and blood pressure. Example, if there's high excess amount of salt, aldosterones regulation is reduced thus minimising absorption of salt through the nephrons which leads to large amount of salt and water being excreted.

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    Re: HSC Biology Marathon 2015

    (8 marks)

    "Our knowledge of biology is increased by scientists exploring and testing ideas using available technologies. The explanations of scientists are then
    verified or modified by the work of later scientists using newer technologies. "


    Justify this statement using the work of FOUR named scientists who have contributed to the development of ideas on inheritance.

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    Re: HSC Biology Marathon 2015

    Quote Originally Posted by Mr_Kap View Post
    (8 marks)

    "Our knowledge of biology is increased by scientists exploring and testing ideas using available technologies. The explanations of scientists are then
    verified or modified by the work of later scientists using newer technologies. "


    Justify this statement using the work of FOUR named scientists who have contributed to the development of ideas on inheritance.
    I can only think of Sutton, Mendel and Morgan, which other scientist can I speak about with an adequate amount of information?

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