Biology Marathon 2006 (1 Viewer)

[Cade]

Differenciate between haemodialysis and peritoneal dialysis

Haemodialysis- when blood is pumped out of the body and filtered thru a dialyser, which consist of a dialysis solution, semi-permeable membrane and compartment for blood. anti-clotting factor is also added into the blood.takes 3.5 hours. [blood is "cleaned" outside the body]
Peritoneal dialysis- dialysis solution is pumped into the person's abdominal cavity via catherer. before that the abdominal cavity is lined with peritonium.this takes 4.6 hours [blood cleaned from inside the body]

Question:1. what is the difference between hibernation and dormancy?
2. explain protein synthesis---(mRNA and tRNA)

 

[Cade]

Question: Outline the role of phagocytosis in active transport (not immune defence)[/quote]

errr...what is this? i am totally lost... LOLZ

 

[Dr_Doom]

Question: Outline the role of phagocytosis in active transport (not immune defence)

errr...what is this? i am totally lost... LOLZ[/quote]

lol I'll just tell you.

It's a form of Endocytosis where the cells absorb molecules to assist them in passing over membranes, Phagocytosis is one method of enfulfing the molecules and Pinocytosis is another.

1. what is the difference between hibernation and dormancy?

Hibernation is where animals depress their metabolic rate to only a few beats a minute. It assists in dealing with cold temperatures during winter to conserve heat by using the least amount of energy necessary.

Dormancy is when organisms (inc plants) slow or stop their metabolism through predictive or consequential means. This minimizes metabolic activity hence conserving energy.

2. explain protein synthesis---(mRNA and tRNA)

- In the nucleus the DNA is unwound by RNA polymerase which is initiated by the promotor.
- A complementary strand to the DNA is formed called messenger RNA (mRNA). This is known as Transcription
- The mRNA is cut into exons and introns, the exons (coding) bind together and the introns (non-coding) may be used to assist in the mRNA crossing out into the cytoplasm.
- When the mRNA is in the cytoplasm it travels to the Ribosomes and one ribosome starts synthesizing each part along the mRNA that will form a different polypeptide.
- The Ribosomes bring down a tRNA has an anticodon which matches to it's complementary triplet on the mRNA (codon). Translation
- The specific tRNA brings an amino acid with it, which connects to the next tRNA's amino acid through peptide bonds. Translation
- Once the mRNA strand is fully synthesized the amino acids line up to form polypeptide chain(s).
- The polypeptide chains fold over and produce a specific protein.

Question: Explain THREE adaptations that a plant may have to cope with fluctuating salt environments in estuarines.

 

[Tim035]

Keep up the good work guys, some of these answers have included just snipets of words or a sentence where I've gone, hey thats a really good point and not something I've included in my summaries:

ANS:
- Most plants cannot tolerate high level of salt, in the roots it can lead to root stress and in the leaves in can be toxic, sodium ions may also inhibit the activity of enzymes in the palnt. Plants that can tolerate higher levels of salt are known as Halophytes (don't quote me on spelling), Mangroves are an example of such a plant.
- Some mangroves are capable of excluding excess salt entering through the roots via a process called ultra filtration in which tiny pores in the roots prevent large salt molecules from passing through.
- The Grey Mangrove is an example of a salt excretor, having specialised glands in their leaves in which salt is concentrated and then actively excreted from the plant. The salt is often seen on the leaves as crystals which wash off in the rain.
- The milky Mangrove is an example of a salt accumulator, it concentrates or accumulates salt in bark or older leaves which are then shed from the plant. Removing excess salt with them.

Qus: Describe a methodology used in cloning.

Umm also another general question, do you think bacteria that are transgenically designed to produce insulin would be classified as an example of a transgenic Animal. If not whats another specific example because all I have for transgenic animals besides that are trout and pigs which are transgenically designed to produce larger amounts of growth hormone so they grow bigger faster.

 

[Dr_Doom]

I didn't know mangroves secreted salt through their roots, I thought they were just to absorb oxygen from the air because the muddy soil lacks it :|

Qus: Describe a methodology used in cloning.

Nuclear Transfer is used to produce identical copies of whole organims.
1) DNA is extracted from the animal wishing to be cloned.
2) The DNA of an unfertalized egg is extracted.
3) Electro current is used to bind the DNA and egg.
4) Egg is grown to a certain stage and injected in another species to give birth to clone.

Nah only use the insulin example for recombinant DNA technology, gene cloning or maybe gene therapy. For the trangenic speices one, there are alot you can do, I think I remember one where strawberries are given an antifreeze gene from salmon so that they can be grown in colder conditions. Idk though you should research it. What I'm using is bt cotton where they gave it a gene to kill a certain caterpillar.

Question: Distinquish between prokaryotic and eucaryotic cells

 

[Petinga]

Eucaryotic cells have membrane bound organelles and nucleus such as protozoans.
Procaryotic cells have no membrane bound organelles or nucleus such as bacteria.

Question: Identify how current reproductive technologies have the potential to alter the genetic compostion of a population.

 

[Tim035]

I didn't know mangroves secreted salt through their roots, I thought they were just to absorb oxygen from the air because the muddy soil lacks it :|

Qus: Describe a methodology used in cloning.

Nuclear Transfer is used to produce identical copies of whole organims.
1) DNA is extracted from the animal wishing to be cloned.
2) The DNA of an unfertalized egg is extracted.
3) Electro current is used to bind the DNA and egg.
4) Egg is grown to a certain stage and injected in another species to give birth to clone.

Nah only use the insulin example for recombinant DNA technology, gene cloning or maybe gene therapy. For the trangenic speices one, there are alot you can do, I think I remember one where strawberries are given an antifreeze gene from salmon so that they can be grown in colder conditions. Idk though you should research it. What I'm using is bt cotton where they gave it a gene to kill a certain caterpillar.

Question: Distinquish between prokaryotic and eucaryotic cells

Lol yeah Everyone knows good old BT cotton. But I've noticed the dot point actually says you should be able to know both a animal and plant example of a transgenic species. Yeh I've heard of strawberries with anti freeze genes from salmon combined with thim. I guess that would be easy enough to go into detail on and the advantages of doing so aren't to hard to describe.

ANS: Current reproductive techniques which may alter the genetic composition of a population are:
- artificial insemination
- Artificial pollination
- And cloning.

Artificial insemination involves sperm collected from a male with usually desired characteristics being inserted into the vagina of the female of the species fertilisation then follows as normal. AI is often used in agriculture, in which bulls with desired characteristics have their sperm collected and used in order to produce offspring who potentially exhibit these same characterisitics (eg. grow faster, larger or live longer).
AI however has the potential to reduce genetic variability in a population. Because a limited number of selected traits are concentrated on, specific alles of a few selected genes will become predominant and others lost. Other inherited features may also be ignored, so that potentially valuable alleles are unwittingly lost from the genetic composition of that group of the species.

Artificial pollination involves the pollen from a male anther being cut off and brushed onto the female stigma. The pollinated flower is then covered in order to prevent pollination from other flowers. It is also used to breed plants with selected charateristics (eg. round pea pods).
AP can reduced genetic genetic diversity if it is used to breed a monoculture in a population of plants with the same set of similar desirable characteristics. It can also effect genetic composition by producing hybrid plants with favourable traits from a different species. Such as Triticale a cross between wheat and rye that has a higher yield and resistance to disease.

Cloning can include asexual reproduction of a species, cutting and tissue culture in plants or taking the nucleus from one individual species and transferring it to a enucleated egg which is then implanted into a surrogate.
Cloning may lead to very selected varieties of plants or animals being grown as the expense of others which are lost. Because a field of cloned crops for example are identicle in genetic composition, every one of them is susceptable to the same diseases or vulnerable to other enviromental changes such as climate. Cloning also produces less biodiversity as no random assortment of genes or crossing over of homologous chromosomes is occuring as would in normal sexual reproduction.

 

[Dr_Doom]

The dot points just says:

discuss the potential impact of the use of reproduction technologies on the genetic diversity of species using a named plant and animal example that have been genetically altered

Reproduction technologies are as you said:
- artificial insemination
- artificial pollination
- cloning

So you don't just have to do a trangenic species for the animal example. You could do dolly the sheep. xD

I'll do a question since you forgot

Question: Decribe what the lymph system is made up of and it's role in the body.

 

[Petinga]

Lymph is a fluid that drains from intercelluar spaces into the lymph vessels. Lymph flows through the lymph vessels and rejoins the blood at the heart. At various stages along the lymph vessles there are lymph nodes which filter out pathogens and other foreign particles. Also the lymph nodes produce lymphocytes involved in the immune response.
Thus the lymph system is one of the bodys 2rd line of defence invoilved in destroying pathogens and other foreign particles.

Question: Why was Mendels work not accepted for some time after he published his results. Give 2 reasons.

 

[Dr_Doom]

- He wasn't a recognised scientist
- He only showed his results to a small group of scientists and they might not have understood.

Question: Name a transitional fossil and how it shows evidence of evolution.

 

[Petinga]

Transitional fossils forms are the missing link between ancestral and descendent groups showing characteristics of both ancestral and descendt groups. An example is the Arcaheopteryx which shows both reptilian features (claws and long jointed tail) and bird like featurees (feathers, wings and beak). This shows the evolution of birds from reptiles. Thus suppoorts trhe theory of evolution which shows the gradula change in organisms over time on earth.

Questiuon: Describe 2 other pieces of evidence for the theory of evolution

 

[Dr_Doom]

Biochemistry: Scientists compared human amino acid sequences of cytochrome-c between organisms and found humans are closely related to chimpanzees.

Biogeography: Similar species such as waratahs were found on the east coast of Australia and South America. This shows that the continent were once joined together. This is an example of divergent evolution.

Question: Outline the Darwin and Wallace theory of evolution by natural selection.

 

[simplistic]

the darwin / wallace theroy outlines that characteristeics favourable to the reproduction and survival of an organism will be selected for and over time new speices will emerge in reponsce to environmental change adaptive radiation referes to the varaity of species which evlove from a common ancestor due to isolation and migration
if a group of organisms were to become isloated from a population there is a high chance that they will undergo different environments and thus face different selectiuon pressures. eventally the group would change suffiently that they will appera as diff species
adaptive radiation accounts for both divergant and convergant evolution
divergant evoultiuon is when closesly related speices undergo different enviromental selection pressures. as each envurimnet changes diiferently
different fetaures will be selected for and in due time the species will appear diiferent eg darwins finches
covergent evolution is when un lrealted species living in similar environments have similar structual physilogical or behavioural features selected for.
overtime these organism will apeear similar and seem to be from the same species eg dolphin and shark
dolphin are mammales and sharks are fish yet both have similar stream lined body and same fins

ps:does it miss out on any important point ?
is it too long

 

[Petinga]

Darwin and Wallace theory of evolution by natural selection and isolation applies to both converging and diverging organisms. Natural selection in both cases provides genitc variation in a population selecting those with favoured characteristics to proliferate.

Divergent evolution is the process by which organisms from a common ancestary move into different environemnts or take on different roles in an environement; deveolp adaptations ansd with isolation diverge into distictly different species. e.g The 14 different species of Darwins Galapagos Isalnd finches.
Convergent evolution is the process by which relatively unrelated organisms are exposed to similiar environemtnal conditions leading to the evolution of similiar characterisitcs and features. e.g. the australian marsupial mole and the european mole.

Question: Describe the work of Thomas Morgan Hunt on genetics

 

[simplistic]

he wanted to recreate mendels pea plant expeirment but on fruit fly eye colour
exp :1
red feamle white male
100% red eyes this led him to propose that red eyes were dominant
exp:2
f1 cross hetrozygous red eyed femal and red male
females were all white and males wre 50:50
exp:3
white male with f1female (red hetrozygous)
50:50 red to white both male s and females
thid led himto belive eye colour is on the sex chromosomes as normal mendles 3:1 ratio didnt show

 

[Tim035]

he wanted to recreate mendels pea plant expeirment but on fruit fly eye colour
exp :1
red feamle white male
100% red eyes this led him to propose that red eyes were dominant
exp:2
f1 cross hetrozygous red eyed femal and red male
females were all white and males wre 50:50
exp:3
white male with f1female (red hetrozygous)
50:50 red to white both male s and females
thid led himto belive eye colour is on the sex chromosomes as normal mendles 3:1 ratio didnt show

Your sure? according to my notes, red eyes was inherited in an autosomal fashion, it was only White eyes which he concluded was carried on the X chromosome.

 

[simplistic]

dunno
but the whole concept was to prove that some gens dont have 3:1 ratio but are eithre sexlinked or codominant
the gene for fruit flie eye colour is on the X chromosome
so alleles for either red or white should be found at identical loci
the definition of alleles are alternate forms of a gene which found at identical loci on homologous chromosomes
is there an exception to this definition ?

 

[simplistic]

social and political influnece on the development on thoeirs of evolution ...
does anyone know info about diiferent theories such as natural thelolgy creationism darwinism esentialism etc ?

 

[UzurOger]

Analyse the historical development of theories of evolution and assess social and political influences on these developments

• Age of earth (6000 years) based on literal interpretation of biblical creation story
• Geologists began to question idea of young earth (erosion deposition and uplift are slow processes)
• Attempts at classification of organisms revealed complexity and suggested interrelationships between species
• Fossil sequences suggested organisms changed over time
• Many biologists began to doubt the fixicity of species and suggested that organisms changed over time

1809- Lamarck proposed that use or disuse of body parts or changes during organism’s lifetime was passed onto offspring, characteristics were inherited i.e. giraffe, long neck
Proved incorrect but still challenged belief in Creationism
Helped make Darwin’s ideas more acceptable

1859- (Around same time as Wallace) Darwin published his ideas- Origin of Species

Before Darwin predominant view in Western cultures was creationism (species not changed nor related)- diversity of living things was created for their encironments at the same time by God in 6 days.
Idea that humans are descended from apes, caused social and political outrage.
Darwin rejected by many religious people

Social and Political Influences of Development of Theory

• Influence of church had been very strong in Britain- may have been reason why Darwin delayed publishing his ideas- wife was committed Christian
• Industrial revolution provided many tools for the scientist and science was becoming a respectable occupation for gentlemen. Geologists were vocal in suggesting that the earth was much older than church claimed. Natural selection is slow process and necessitates old earth
• Britain was strong power and had established many overseas colonies. Exploration was encouraged and this provided the opportunity for many naturalists to sail around world. Darwin’s theories were formulated on such a voyage, especially while visiting Galapagos Islands off coast of South America
• For many of ruling class, acceptance of the theory and its ideas of a struggle for existence justified their ideas that black skinned people were inferior to whites and they had no moral obligation to help the poor. They considered themselves to be better fitted.

1968- U.S. Supreme Court ruled ban on teaching evolution was unconstitutional


Just some stuff i found in my libary of Bio Notes

umm Compare the structure of arteries, capillaries and veins in relation to their function

 

[simplistic]

but do you or anyone have anything abpout natural theology and its social / political issues ?
there was a 8 mark question about that dot pnt
andf the critera wantd to discus 3 theories ..............