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Biology Marathon 2006 (1 Viewer)

Dr_Doom

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I'd hate to get a question like that worth 8 marks! Evolution topic is the worst part about biology coz you needa know all these guys names who made up a bunch of crap and the effects it had on society. It's more history than biology.
 

Petinga

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Arteries are involved in moving blood away from the heart under high pressures. Thus have arteries have thick muscular walls to withstand these high pressures. These do not pump blood or do not contain valves.
Veins are invloved in moving blood towards the heart under loww pressures. Thus veins have less thick and muscular walls than arteries due to lower pressures. Also contain valves to prevent the backflow of blood due to low pressures.
Capillaries are involved in moving blood between the arteries and veins. Also allow materials to diffuse in and out of walls into cells. Thus capillaries have very thin walls about one cell thick in diameter and carryy blood under very low pressures.


Question: Describe the role of enzymes in metabolism, chemical compostions and a model for enzyme specificty
 

Tim035

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There were three main philosophies current during the 18th and 19th century that delayed the widespread acceptance of evolution. These were nature theology, literal creationism essentialism.
Natural theology had its goal in demonstrating God’s power through a study of the biological world. Amazing adaptations and the supposed hierarchy of living things were seen as proof of God’s handiwork and role in creation.
Essentialism held that everything had an essence or typical form that was unchanging and fixed since the time of creation.
Creationists took as literally true the biblical stories of creation and that the earth of was only a few 1000 years old.
In France, the French revolution and Napoleonic forms had created an environment where Lamarck was able to propose that living things had evolved but in conservative England such talk was nonsense. The fact that Lamarck was French was enough to make his ideas unwelcome in England. If nature were self evolving, if the clergy could not point to miraculously created species as a sign of God’s power, the Churches legitimacy would be undermined. It was believed civilized man would return to savagery if people accepted that society and nature had evolved unaided.
Starting in the 18th century, new discoveries began to change old beliefs, in astronomy the earth was shown to be one of several planets that revolved around the sun and that man was not the centre of the Universe. There was increasing urge to find natural explanations for events.
In Edinburgh where Darwin was a student, many prominent people were progressive. Darwin was a close friend of Robert Grant and supported an evolutionary explanation of the diversity of organisms. Radical thinkers lectured at the university and in medical and geological classes students were being taught about progression and change. Through out his life Darwin associated with free thinkers and dissenters. Many of Darwin’s friends and family were radical dissenters who urged for social and religious reform. But radicals and materialists were being persecuted- William Lawrence had been forced to resign his post at the college of surgeons and recent his book on evolution “Lectures on Man” was ruled blasphemous. Which destroyed its copyright and was pirated by the gutter press who published it in cheap forms with flyers denouncing the Church authorities.
In January 1844, the idea of evolution of species was associated with riot and revolution. Street Atheists touted evolution and vowed to mash the Anglican state. Darwin’s clerical friends stood to lose their livelihoods, he was appalled at the idea that the theories he was secretly working on could lead him to being accused of betraying his privileged class. This was one of the reasons that Darwin was so reticent to publish his ideas.
 

Dr_Doom

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Enzymes are involved in the metabolism, they help speed up or slow down a reaction so they are 'biological catalysts'. They can break down a substrate into products, called catabolic reactions, or they can synthesis subtrates together called anabolic reactions. This is done on the active site. Enzymes are proteins and are composed of amino acids in a polypeptide chain. They contain a number of chemicals including oxygen, nitrogen and sulfar. They require co-enzymes such as vitamins and ATP to function. As well as co-factors which are metallic ions such as magnesium and potassium. The model used to show the specificty of an enzyme is the lock-n-key model which shows that the substrate has an exact fit on the enzymes active site.

Question: Describe autosomal and sex linked inheritene uncluding examples of both dominant and recessive diseases.
 

Dr_Doom

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Tim035 said:
There were three main philosophies current during the 18th and 19th century that delayed the widespread acceptance of evolution. These were nature theology, literal creationism essentialism.
Natural theology had its goal in demonstrating God’s power through a study of the biological world. Amazing adaptations and the supposed hierarchy of living things were seen as proof of God’s handiwork and role in creation.
Essentialism held that everything had an essence or typical form that was unchanging and fixed since the time of creation.
Creationists took as literally true the biblical stories of creation and that the earth of was only a few 1000 years old.
In France, the French revolution and Napoleonic forms had created an environment where Lamarck was able to propose that living things had evolved but in conservative England such talk was nonsense. The fact that Lamarck was French was enough to make his ideas unwelcome in England. If nature were self evolving, if the clergy could not point to miraculously created species as a sign of God’s power, the Churches legitimacy would be undermined. It was believed civilized man would return to savagery if people accepted that society and nature had evolved unaided.
Starting in the 18th century, new discoveries began to change old beliefs, in astronomy the earth was shown to be one of several planets that revolved around the sun and that man was not the centre of the Universe. There was increasing urge to find natural explanations for events.
In Edinburgh where Darwin was a student, many prominent people were progressive. Darwin was a close friend of Robert Grant and supported an evolutionary explanation of the diversity of organisms. Radical thinkers lectured at the university and in medical and geological classes students were being taught about progression and change. Through out his life Darwin associated with free thinkers and dissenters. Many of Darwin’s friends and family were radical dissenters who urged for social and religious reform. But radicals and materialists were being persecuted- William Lawrence had been forced to resign his post at the college of surgeons and recent his book on evolution “Lectures on Man” was ruled blasphemous. Which destroyed its copyright and was pirated by the gutter press who published it in cheap forms with flyers denouncing the Church authorities.
In January 1844, the idea of evolution of species was associated with riot and revolution. Street Atheists touted evolution and vowed to mash the Anglican state. Darwin’s clerical friends stood to lose their livelihoods, he was appalled at the idea that the theories he was secretly working on could lead him to being accused of betraying his privileged class. This was one of the reasons that Darwin was so reticent to publish his ideas.
Woah thanks! I'm printing that xD

Is BOS slow or what?
 

Tim035

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Lol no problems guys, cept keep it hush I can't have all the state knowing as much as I do Lol jks.

My tutor says that its unlikely they'd ask a big question on social/political influences on evolution because its such a touchy subject even today. More likely they'd ask something indirectly related to it, Such as the Catholic trial where the question was "Darwin and Wallance can be credited as the first people to propose a theory of evolution. Assess the validity of this statement".
 

Tim035

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Jeez... autosomal, sex linked, dominant and reccessive diseases I'd like to see that be asked in the HSC.

Well for sex linked theres red green colour blindness which is reccessive to normal colour vision and is carried on the x chromosome. So unless the father is colour blind and the mother is colour blind or heterozygous it is unlikely For a female to inherit the condition.

Do they have to be diseases? lol..
Only other specific example I know is blood types which are inherited autosomally. With the alleles for A & B blood type being dominant and the blood type O being recessive. Therefore if a person aquires the alleles for both A and B blood type, co-dominance will actually occur in that the persons blood type will be AB. Blood type O will only ever occur if both the alleles the person aquires are O.
 

Cade

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Questions, ppl...

Describe clonal selection theory and the works of scientists, Niels Jerne and MacFarlane Burnet. Justify your answer.
 

Tim035

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lol don't worry I thinnnnkkk if I remember correctly those two scientists are part of the 'genetics the code broken' option or something like that.
Keep it just to the core for this thread buddy, if u need help with options please post in the appropriate forum.
It'd be like me asking you "explain why not all stimulus generate an action potential"

Anyway I'll kick start the questions again:
Describe the relationship between the structure and behaviour of chromosomes and the inheritance of genes
 

Dr_Doom

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Chromosomes are large DNA molecules wrapped around histone protiens called nucleosomes. The DNA contains many different sequences of bases called genes, and these are passed on through meiosis in the formation of gametes to the offspring... Yeah that's all I could think of lol

Clonal Selection Theory is for search for better health isn't it? Anyway it's when a helper TCell comes in contact with an antigen which triggers it to make millions of clones into plasma Bcells (which produce antibodies), memory Tcells, suppressor Tcells and cytotoxic (killer) Tcells which attack the pathogen directly. Hmmn what are active Tcells then?

Question: Differenciate between selective breeding and hybridisation.
 
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Petinga

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Meiosis is a type of cell division that produces sex cells (i.e gametes) that contain half the number of chromosones as the original parent cell.
During Meiosis, different pairs of homologous chromosones behave indepentely of each other. The genes on the different homologous chromosones behave independtel and randomly, known as random segration. And since the different chromosone pairs contain different genes then the gametes produced are genetically unique and different.

Chromosones are composed of DNA and protein. DNA is a nucliec acid coiled tightyl arounbd a protein core. Genes are a short length of chromosones and thus composed of DNA.

Question: Describe inflammation response and phagocytosis
 

angmor

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the inflammation response is a process in the second line of defence that involves the dilation of blood cells and a rush of blood to a constricted area. this allows white cells to move in to inhibit the infection.
phagocytosis is also a process of the second line of defence and involves the phagocytes such as lymphocytes, macrophages,etc. engulfing foreign material and attempting to ingest it.

NEXT QUESTION : <b> Explain the techniques Mendel used to ensure his success </b>
 

simplistic

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tim i dont want to scare you lol but theire both in serach for the better health

Question: Describe inflammation response and phagocytosis

mast cells (infected cells) relesae chemicals such as histamine which initiate an immune response such as blood vessel dilation so taht more wbc can move into the area as well as keeping the pathogens in one spot( prevent thier spread)

phagocytosis is where nutrophile sand macrophages engulf and destroy antigens usuing lysososmes and digestive enzeymes
nutrophiles are shorter lasting and move in both blood and tissues were as macrphages (which are mature monocytes) are longer lasting and move thru the tissue part
 

angmor

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arent lysosomes only used during cell death by sealing off pathogen? they activate the process which causes the cell to die around the foreign material.
 

Dr_Doom

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Explain the techniques Mendel used to ensure his success

-Used a variety of traits
-Easily identifiable traits
-Worked with large numbers
-Only one trait at a time to not get confused
-Bred plants for 2 years before to make sure they were purebred

Question: Compare the kidneys of fish and mammals

Question: Define the terms homeostasis and enantiostasis

Question: Contrast the theories of gradualism and punctuated equilibrium

Question: Explain how the environment affects the phenotype of an organism and give an example

whoever does all those first WINS!
 

Petinga

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Q 1.
The Kidney is a complex organ of the excretory system of both the fish and mammals which is involved in filtration, reabsobtion and secretion.
The role of the kidney in the mammal is to excrete nitrogenous wastes as well as maintain osmosregulation.
The role of the kidney in fish varies depending on its environement. However it is primarily involved in osmoregulation and nitrogenous wastes are excreted through gills
In Marine fish, the kidney excretes scant amounts of isotonic urine in attempt to conserve water and rid salts. In freshwater fish, the kidney excretes copious amounts of dilute urine in attempt to conserve salts and rid excess water.

Q2. Homeostasis is the process by which organiusms maintain a relatively stable or constant interanl environmenrt despite changes in the external environement. Enantiostasis is the maintenace of metabolic and physiological funtioning in response to varitions in an organisms environment.

Q3. Darwins theory of evolution by natural selection suggessts that evolutionary change occurs gradually over long periods of time.
In the 1970's Gould and Eldridge, proposed the concept of punctuated equilibrium as the mecahnism for evolution. This suggests that evolutiuonary change occurs rapidly over short periods of time followed by long periods of little change (i.e equilibrium).

Q4. The phenotype of an oragnism is not only dictated by its genotype but also by the environment whjich it inhabits. The effect of an allele can be masked or enhganced by varitaions in an environment, showing that the environemtn influences the phenotype. Some factors that affect phenotype are soil type, light, nutrients, water and competition
E.g. Hydrangeas produce blue fl;owers in acidic soils and pink flowers in basic soils
 

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