HSC Biology Marathon 2015 (1 Viewer)

[tfw english]

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

A prion is a protein altered from its previous structure, and can cause other proteins to alter, creating more prions in a chain-like reaction. Prions are responsible for diseases such as mad-cow disease. These are observable under a microscope.

A virus however, consists of DNA or RNA enclosed in protein, living inside living cells. They are so small they cannot be seen with a light microscope. Viruses cause diseases such as influenza and AIDS.

 

[Mr_Kap]

Identify where crossing over would occur, and explain how crossing over affects the inheritance of genes .3 MARKS

 

[tfw english]

Identify where crossing over would occur, and explain how crossing over affects the inheritance of genes .3 MARKS

Crossing over occurs during the process of meiosis. It is the process in which homologous chromosomes exchange genes and so the resulting combinations of alleles on chromatids differ from those originally on the parent chromosome. This affects the inheritance of genes as it produces many different gene combinations which are are different from the parents and therefore the offspring inherits a variety of randomised genes from both parents.

Is this alright? Feel like I'm forgetting something

 

[Mr_Kap]

Crossing over occurs during the process of meiosis. It is the process in which homologous chromosomes exchange genes and so the resulting combinations of alleles on chromatids differ from those originally on the parent chromosome. This affects the inheritance of genes as it produces many different gene combinations which are are different from the parents and therefore the offspring inherits a variety of randomised genes from both parents.

Is this alright? Feel like I'm forgetting something

Say where in meiosis it occurs.

 

[Flop21]

Identify where crossing over would occur, and explain how crossing over affects the inheritance of genes .3 MARKS

Crossing over occurs when the homologous pairs of chromosomes have lined up at the equator, when adjacent chromatids split and join up with different pieces. Crossing over creates variation, creating new combinations of alleles as genetic material has been exchanged between different chromosomes. Thus, the inherited genes have greater variation.


EDIT: Oh right forgot to say it occurs during meiosis.

 

[tfw english]

Say where in meiosis it occurs.

So prophase 1?

 

[Flop21]

k so I always get confused with Sutton and Boveri. I know what they BOTH did, but I find it hard to talk about them separately. Do we need to know what each did separately? Like what they discovered?

 

[tfw english]

k so I always get confused with Sutton and Boveri. I know what they BOTH did, but I find it hard to talk about them separately. Do we need to know what each did separately? Like what they discovered?

It's pretty much the same thing that they both independently discovered I think? Isn't the only difference how they came about it? As in sea urchins and grasshopper testes?

Not sure either

 

[Mr_Kap]

k so I always get confused with Sutton and Boveri. I know what they BOTH did, but I find it hard to talk about them separately. Do we need to know what each did separately? Like what they discovered?

yah.
I'm pretty sure bluegas answered it once ages ago on a different thread. I'll go looking for it lol.
If not it is in my half yearly response where i got full marks..just have to find it.

 

[Mr_Kap]

Found something from a past trial i did. This was the sample answer.

Boveri demonstrated a connection between chromosomes and heredity by discovering that both sperm and egg contributed genetic material to the zygote and both were required for ‘normal’ development of the offspring. Sutton made a link between hereditary factors (genes) and the behaviour of chromosomes during meiosis. Both of these discoveries were vital in the understanding of how characteristics are passed on from parents to offspring.

Obviously you need to mention the grashopper test for sutton and the sea urchin for boveri, The hereditary factors that sutton found were the same "factors" proposed by mendel.

 

[Flop21]

Explain how gene expression contributes to our health. (3 marks).

 

[Flop21]

And another one,

Outline the historical developments to the theory of evolution. (3 marks)

 

[tfw english]

Explain how gene expression contributes to our health. (3 marks).

Each gene inside a cell can be 'switched off' and 'switched on' by a number of conditions both within the cell and outside the cell. A gene is expressed when it is ‘switched on’ and the DNA encoded within this gene is converted into polypeptides.

The body’s cells are always being replaced, thus the correct specialised cells must be produced to replace them. This is done through mitosis, followed by gene expression. Healthy cells have their cell cycle regulated by proteins that are produced by different types of genes. Therefore the expression of genes within certain cells contributes to the overall health of the organism as it provides an efficient continuation of the cell cycle.

 

[Mr_Kap]

And another one,

Outline the historical developments to the theory of evolution. (3 marks)

This is fucked this dotpoint. I'm not gonna learn it.

Idk what to write, there is so much on this. who is important who isn't?

 

[Mr_Kap]

I'm gonna take a break from bio for a bit --> Maybe 2 or 3 hours.

I'll leave an 8 marker.

The influenza virus has a high rate of mutation which can lead to changes of the viral surface antigens that contain protein. Analyse the impact of high mutation rates for this virus and the importance of human health. 8 MARKS.

I suggest whoever answers this to answer it in dotpoints of what you are going to write...takes quicker than writing the whole shit out, and ill provide the markers notes and marking guidlines to this question after so we can compare our answers to.

 

[tfw english]

This is fucked this dotpoint. I'm not gonna learn it.

Idk what to write, there is so much on this. who is important who isn't?

Yeah it's shit.
But if I had to choose, I'd go with:

- Erasmus Darwin (1731-1802) — suggested that the strongest and most active individuals would survive and continue a species.

- Jean-Baptiste Lamarck (1744-1829) — suggested that features acquired during the life of an organism could be passed on to its offspring. Although later discredited, continued the thought that led to the modern theory of evolution.

And then finish off with Darwin/Wallace:

Alfred Russel Wallace (1823-1913) — independently came up with the theory of natural selection and wrote to Darwin to discuss it. This prompted Darwin to publish his theory.
Charles Darwin (1809-1882) — developed his theory of evolution based on observations he made on a journey to South America on HMS Beagle. By the early 1840s he had documented the main points of his theory but was reluctant to publish his work because of the political and religious upheaval it would cause.

 

[Flop21]

This is fucked this dotpoint. I'm not gonna learn it.

Idk what to write, there is so much on this. who is important who isn't?

I think you just mention scientists for this dot point.

I'm going to remember, Erasmus Darwin (Darwin's father) - first suggested that all life came from a single source, Lamarck - proposed the idea of 'use and disuse' (an incorrect idea about evolution), and then Charles Darwin.

Not going to bother remembering years though.

 

[Flop21]

I'm gonna take a break from bio for a bit --> Maybe 2 or 3 hours.

I'll leave an 8 marker.

The influenza virus has a high rate of mutation which can lead to changes of the viral surface antigens that contain protein. Analyse the impact of high mutation rates for this virus and the importance of human health. 8 MARKS.


I suggest whoever answers this to answer it in dotpoints of what you are going to write...takes quicker than writing the whole shit out, and ill provide the markers notes and marking guidlines to this question after so we can compare our answers to.

I don't really get the last sentence of the question. Analyse the impact of high mutation rates for this virus...... AND the importance of human health.

Does that mean, the impact of the high mutation rates on the virus + human health?

I'll answer in dot point / plan form anyway:

- Define mutation
- Cause unexpected and possibly harmful or deadly effects on the human body

- However, mutation could also cause virus to not reproduce normally.


- Vaccination
- Memory lymphocytes ineffective against new strains of the virus
- Thus, previous vaccinations against the virus become ineffective > regularly updated vaccinations needed.




I think I definitely need a lot more here, just not sure what else to write.

 

[Flop21]

Here's another question if anyone wants to have a go.

Define 'mutagen' and discuss the evidence for the mutagen nature of radiation (3 marks).

 

[Mr_Kap]

I don't really get the last sentence of the question. Analyse the impact of high mutation rates for this virus...... AND the importance of human health.

Does that mean, the impact of the high mutation rates on the virus + human health?

I'll answer in dot point / plan form anyway:

- Define mutation
- Cause unexpected and possibly harmful or deadly effects on the human body

- However, mutation could also cause virus to not reproduce normally.


- Vaccination
- Memory lymphocytes ineffective against new strains of the virus
- Thus, previous vaccinations against the virus become ineffective > regularly updated vaccinations needed.




I think I definitely need a lot more here, just not sure what else to write.

Human health becomes worsened because the virus keeps mutating and our immune respone as well as vaccines are innefective.