HSC Biology Marathon 2015 (3 Viewers)

[BlueGas]

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

 

[kevinsta]

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?

 

[kevinsta]

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.

 

[kevinsta]

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.

 

[kevinsta]

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.

 

[BlueGas]

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

 

[DepressedPenguino]

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)

 

[DepressedPenguino]

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.

 

[kevinsta]

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

 

[kevinsta]

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

 

[BlueGas]

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.

 

[kevinsta]

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)

 

[DepressedPenguino]

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?

 

[BlueGas]

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.

 

[BOS Secret Service]

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.

 

[BlueGas]

IDK but the Ahmad Shah revised and edited have a decent answer to this.

The answer is quite lengthy though.

 

[DepressedPenguino]

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

 

[BlueGas]

Nah i think the hsc one only asks for ONE specifically

What HSC year?

 

[Flop21]

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.

 

[Flop21]

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.