HSC Biology Marathon 2015 (4 Viewers)

[Mr_Kap]

Distinguish between active and passive transport and relate these to the processes occurring in the mammalian kidney. (4)

Active transport requires an input of energy, usually to move an object against the concentration gradient, while passive transport doesn't require any energy input and is usually the flow of something with the concentration gradient. In the mammalian kidney both active and passive transport is used in reabsorption in the nephron. All amino acids, glucose, vitamins and ions are absorbed back into the body through active transport, while all water reabsorbed is by the passive process of osmosis.

Someone tell me where these occur

 

[tfw english]

Active transport requires an input of energy, usually to move an object against the concentration gradient, while passive transport doesn't require any energy input and is usually the flow of something with the concentration gradient. In the mammalian kidney both active and passive transport is used in reabsorption in the nephron. All amino acids, glucose, vitamins and ions are absorbed back into the body through active transport, while all water reabsorbed is by the passive process of osmosis.

Someone tell me where these occur

Passive transport happens after the initial filtration in the Bowman's capsule as water returns via the interstitial fluid from the tubule to the capillary
And then active happens with the ions in the blood, depending on their concentration they can be transported to cells in the nephron tubule and then secreted by the cells into the tubule.

 

[Mr_Kap]

im gonna take a bit of a break from this....will be back in around an hour.

EDIT: Actually i'll do some more questions for a bit

 

[Mr_Kap]

The Murray-darling Basin is the natural habitat of the Murray Cod, a native Australian frshwater fish. Explain the implications of increase water salinity for the survival of the Murray Cod. 3 MARKS

 

[tfw english]

im gonna take a bit of a break from this....will be back in around an hour.

EDIT: Actually i'll do some more questions for a bit

How about a Blueprint question?

How does the concept of punctuated equilibrium in evolution differ from the gradual process proposed by Darwin? (4)

 

[tfw english]

The Murray-darling Basin is the natural habitat of the Murray Cod, a native Australian frshwater fish. Explain the implications of increase water salinity for the survival of the Murray Cod. 3 MARKS

Increased water salinity would upset the water balance in the Murray Cod because freshwater fish normally have a higher salt concentration than the environment and due to their osmoregulative nature, they choose to tolerate these changes rather then adapt to them, and this results in the increase of uptake of osmosis and the production of dilute urine. Increasing the salinity in this environment would lead to an increased loss of water from the fish and so eventually dehydrating or dying.

 

[Mr_Kap]

How about a Blueprint question?

How does the concept of punctuated equilibrium in evolution differ from the gradual process proposed by Darwin? (4)

The concept of gradualism proposed by Charles Darwin was that organism evolved gradually as the environment gradually changed. However, the concept of punctated equillibrium differs from Darwin's gradual evolution in that evolution is seen as long periods where there is little change in organisms (equillibrium). This is followed by a shorter period where there are rapid changes due to significant changes in environment and then this process is repeated. There is evidence for punctuated evolution from the fossil record where there are mass extinctions of organisms followed by the appearance of new species.

 

[tfw english]

The concept of gradualism proposed by Charles Darwin was that organism evolved gradually as the environment gradually changed. However, the concept of punctated equillibrium differs from Darwin's gradual evolution in that evolution is seen as long periods where there is little change in organisms (equillibrium). This is followed by a shorter period where there are rapid changes due to significant changes in environment and then this process is repeated. There is evidence for punctuated evolution from the fossil record where there are mass extinctions of organisms followed by the appearance of new species.

10/10

 

[Mr_Kap]

Increased water salinity would upset the water balance in the Murray Cod because freshwater fish normally have a higher salt concentration than the environment and due to their osmoregulative nature, they choose to tolerate these changes rather then adapt to them, and this results in the increase of uptake of osmosis and the production of dilute urine. Increasing the salinity in this environment would lead to an increased loss of water from the fish and so eventually dehydrating or dying.

A good answer. 3/3. maybe at the end though mention it will die because it won't be able to produce concentrate urine to counteract the water loss from the fish.

 

[Flop21]

How about a Blueprint question?

How does the concept of punctuated equilibrium in evolution differ from the gradual process proposed by Darwin? (4)

The concept of punctuated equilibrium states that there are long periods of little evolutionary change, followed by short bursts of rapid evolutionary change. These short periods of rapid evolutionary change are caused by extreme changes to the environment creating new environmental pressures and thus forcing those with favourable characteristics to survive. This process differs from Darwin's theory of evolution because Darwin stated that evolution occurs gradually over a long period of time. [whereas punctuate equilibrium states there are long periods of little evolutionary change.]


Bit disjointed sorry.

 

[Flop21]

Discuss how a named disease results from an imbalance of microflora in humans (2 marks).

 

[Mr_Kap]

"All mutations are harmful"

Discuss this statement. 3 MARKS

 

[tfw english]

Discuss how a named disease results from an imbalance of microflora in humans (2 marks).

Candidiasis is a disease caused by an imbalance in the numbers of the fungus, ‘Candida albicans’.
The fungus is usually kept in check from competition from other microbes such as bacteria living in the same area
The taking of certain medications, such as wide-spectrum antibiotics (which can kill beneficial bacteria), or contraceptive pills, can upset the balance of microflora in the body, which can result in an increase in the numbers of the Candida fungus, leading to thrush.

 

[Mr_Kap]

Discuss how a named disease results from an imbalance of microflora in humans (2 marks).

Flop21 is a disease that results from an imbalance of microflora in humans. Usually Flop21 has competition for resources from the normal and unharmful amount of microflora living on the skin of humans. An imbalance of microflora caused by intake of too many antiobiotics, or washing body too frequently, can cause these microflora to die off, hence the pathogen that causes Flop21 has no more competition for reasources and can begin to multiply on the skin. This eventually leads to Flop21 in humans.

 

[Flop21]

"All mutations are harmful"

Discuss this statement. 3 MARKS

Mutations are caused by mutagens and can cause a change in the base sequence of DNA. For example, ultra violet rays can cause bases to be deleted/removed. The result of this mutation would result in a different or missing amino acid being formed, and thus a faulty protein being created. Proteins are essential to the body as they are the building block of enzymes, which carry out various processes within the human body. Therefore, a faulty enzyme could be harmful.

However, mutations are essential to the process of evolution. They create variation within a species by creating new sources of alleles. These new traits may be advantageous in the environment, thus allowing the organism to survive and pass the trait onto the next generation via reproduction. Therefore, not all mutations are harmful [would you insert a statement saying 'this statement is invalid/unreliable' here?].

 

[Mr_Kap]

Mutations are caused by mutagens and can cause a change in the base sequence of DNA. For example, ultra violet rays can cause bases to be deleted/removed. The result of this mutation would result in a different or missing amino acid being formed, and thus a faulty protein being created. Proteins are essential to the body as they are the building block of enzymes, which carry out various processes within the human body. Therefore, a faulty enzyme could be harmful.

However, mutations are essential to the process of evolution. They create variation within a species by creating new sources of alleles. These new traits may be advantageous in the environment, thus allowing the organism to survive and pass the trait onto the next generation via reproduction. Therefore, not all mutations are harmful [would you insert a statement saying 'this statement is invalid/unreliable' here?].

Just say its incorrect/false.

 

[tfw english]

Mutations are caused by mutagens and can cause a change in the base sequence of DNA. For example, ultra violet rays can cause bases to be deleted/removed. The result of this mutation would result in a different or missing amino acid being formed, and thus a faulty protein being created. Proteins are essential to the body as they are the building block of enzymes, which carry out various processes within the human body. Therefore, a faulty enzyme could be harmful.

However, mutations are essential to the process of evolution. They create variation within a species by creating new sources of alleles. These new traits may be advantageous in the environment, thus allowing the organism to survive and pass the trait onto the next generation via reproduction. Therefore, not all mutations are harmful [would you insert a statement saying 'this statement is invalid/unreliable' here?].

3/3. Not sure about the statement? Could be added, but I think the concluding statement "therefore not all mutations are harmful" should be enough considering what you discussed beforehand and how that relates to the definitive statement, should be good. Not sure though haha

 

[Flop21]

Flop21 is a disease that results from an imbalance of microflora in humans. Usually Flop21 has competition for resources from the normal and unharmful amount of microflora living on the skin of humans. An imbalance of microflora caused by intake of too many antiobiotics, or washing body too frequently, can cause these microflora to die off, hence the pathogen that causes Flop21 has no more competition for reasources and can begin to multiply on the skin. This eventually leads to Flop21 in humans.

I am thrush???!



Compare the structure of a virus and prion, including examples of diseases caused by these pathogens in your answer. (2 marks).

 

[Mr_Kap]

I would finish off: "It is clearly seen that the statement is incorrect as although most mutations are harmful, not ALL mutations are harmful."

 

[Mr_Kap]

Compare the structure of a virus and prion, including examples of diseases caused by these pathogens in your answer. (2 marks).

A prion is an altered protein structure which is non-cellular. An example of a disease caused by a prion is Kuru, and it was spread through cannibalism in New Zealand (eating the brains of the dead which had Kuru Disease).