• Best of luck to the class of 2024 for their HSC exams. You got this!
    Let us know your thoughts on the HSC exams here
  • YOU can help the next generation of students in the community!
    Share your trial papers and notes on our Notes & Resources page
MedVision ad

Biology? Are you ready? (1 Viewer)

E

Effekt

Guest
Describe changes in the composition of blood as it moves around significant parts of the body

If that's asked tomorrow, i'll just snort pencil sharpening and pretend to have fainted
Ugh i would be screwed for this question, All i know is 55% plasma, 45% cellular matter. Plasma is something like 90% water. As oxygen is absorbed into the blood through the lungs the blood turns dark red and is carried to important organs/cells. The it turns light red as it carries nitrogenous wastes + C02.
 

fariss

New Member
Joined
Feb 22, 2011
Messages
12
Gender
Male
HSC
2011
explain why the processes of diffusion and osmosis are inadequate in removing dissolved nitrogenous wastes in some organisms.. no fucking idea
cus like, they're both passive - rely on random movement of molecules.
diffusion is too slow for normal functioning of body, and unable to selectively reabsorb solutes.
osmosis only deals with movement of water, so only water would move out of body, not nitrogenous wastes..
in the kidney, some useful products are absorbed in body - unable to with diffusion (because active transport needed)
osmosis without active reabsorption of water would result in excess water loss.

and yeah.
 

memo15

Member
Joined
Aug 2, 2011
Messages
142
Gender
Female
HSC
2012
explain why the processes of diffusion and osmosis are inadequate in removing dissolved nitrogenous wastes in some organisms.. no fucking idea
loll ok diffusion and osmosis:
1) process are too slow
2) non selective
3) Osmosis- only refers to the movement of water so nitrogenous wastes cant be removed and will build up
 
Joined
Apr 3, 2010
Messages
777
Gender
Male
HSC
2011
next qs uhmm movement of substances in xylem and phloem >.<
Xylem:
Water lost through transpiration is replaced by water from xylem. This creates an osmotic gradient which draws water by osmosis from the xylem. The resulting movement of water from the roots to the leaves is the transpiration stream. It is an entirely passive process which works in tandem with capillary forces including cohesion and adhesion.

Phloem:
Movement of substances in phloem is known as translocation/ source-to-sink. The movement of sugars from the leaves (the source) into the phloem results in a high concentration of solutes in the phloem, which causes water to enter by osmosis. This creates a region of high pressure in that section of the phloem tubes. Because of the raised pressure, the sugar moves through diffusion from areas of higher to lower concentration (sink)

Pretty certain those would be correct
 
Joined
Apr 3, 2010
Messages
777
Gender
Male
HSC
2011
Xylem:
Water lost through transpiration is replaced by water from xylem. This creates an osmotic gradient which draws water by osmosis from the xylem. The resulting movement of water from the roots to the leaves is the transpiration stream. It is an entirely passive process which works in tandem with capillary forces including cohesion and adhesion.

Phloem:
Movement of substances in phloem is known as translocation/ source-to-sink. The movement of sugars from the leaves (the source) into the phloem results in a high concentration of solutes in the phloem, which causes water to enter by osmosis. This creates a region of high pressure in that section of the phloem tubes. Because of the raised pressure, the sugar moves through diffusion from areas of higher to lower concentration (sink)

Pretty certain those would be correct
The xylem one seems a little wonky :S

Anyways, new question: outline the role of hormone replacement therapy in people who cannot secrete aldosterone
 

memo15

Member
Joined
Aug 2, 2011
Messages
142
Gender
Female
HSC
2012
The xylem one seems a little wonky :S

Anyways, new question: outline the role of hormone replacement therapy in people who cannot secrete aldosterone
Aldosterone is a hormone released when salt levels are low in the body. Aldosterone increases the permeablity of the tubules to sodium. Fludrocortisone is administered to people who cann not secrete aldosterone it is given orally once or twice a day and it works the same way as the hormone aldosterone would that is increases the permeablity of the tubules to sodium. Therefore water follows by osmosis therefore regulates blood pressure as well
 

fariss

New Member
Joined
Feb 22, 2011
Messages
12
Gender
Male
HSC
2011
The xylem one seems a little wonky :S

Anyways, new question: outline the role of hormone replacement therapy in people who cannot secrete aldosterone
without aldosterone, the body would be unable to reabsorb salt causing severe dehydration = brain damage/death

is that right?
 
Joined
Apr 3, 2010
Messages
777
Gender
Male
HSC
2011
You guys are sposed to ask questions after you answer them in a way of 'testing' each other
 

memo15

Member
Joined
Aug 2, 2011
Messages
142
Gender
Female
HSC
2012
ok next question brief points about contribution of pasteur and Koch
 

fariss

New Member
Joined
Feb 22, 2011
Messages
12
Gender
Male
HSC
2011
how long are you guys planning to stay up until?
because communication is fucking terrible.. and i feel that i've got a long night ahead.
 

memo15

Member
Joined
Aug 2, 2011
Messages
142
Gender
Female
HSC
2012
how long are you guys planning to stay up until?
because communication is fucking terrible.. and i feel that i've got a long night ahead.
not too late hopefully i dont function well if i dont sleep before the exam
 

lockedbox

Member
Joined
Aug 1, 2011
Messages
113
Gender
Undisclosed
HSC
2011
ok next question brief points about contribution of pasteur and Koch
Pasture disproved the theory of "spontaneous generation" and developed the process of "pasturization" which eliminated microflaura from substances.

coined terms aerobic and anaerobic

-unwittingly provided evidence for the germ theory

Pasture developed a method of determining the cause of disease in "kochs postulates"

-gave evidence for/proved the germ theory

Explain the "first line of defeanse" of the human body
 
Last edited:
Joined
Apr 3, 2010
Messages
777
Gender
Male
HSC
2011
ok next question brief points about contribution of pasteur and Koch
Pasteur did many things:
1. He studied the use of vaccines. He took 50 sheep and inoculated 25 of them with a weakened strain of anthrax. After about 10 days, he inoculated all 50 with a strong dose of the anthrax, which just as he predicted, killed the 25 sheep which were not injected with a weakened strain of the disease. This was the first recorded/ scientific use of vaccine (it was done before by the Chinese, who ground smallpox scabs and ate them).
2. He disproved the spontaneous generation belief of his time. He poured nutrient broth into two swan necked flasks. He boiled the both flasks to kill off any microbes already present (pasteurisation). He then broke the 'neck' of one of the flasks and placed both in an open area. He found that the flask with the 'broken neck' had developed germs or whatever, and so suggested the germ theory.

Koch:
Koch studied the cause of anthrax in sheep also. He isolated the blood of a sheep and noticed that there were microbes in there that usually wouldn't be. He then cultured the microbes and injected them into another sheep. He found this one had also become infected. He removed the blood yet again and found the same microbes were present as before. He then suggested the 'Postulates' for identifying a certain microbe as cause of a disease:
1. The microbe must be present in the blood of an infected animal.
2. The microbe must be isolated and cultured.
3. If injected into a healthy animal, the microbe must cause the disease.
4. When isolated again, it should be the same microbe as that in the first animal

---

Q. the dot point on malaria lol, I can't be bothered writing it
 
Joined
Apr 3, 2010
Messages
777
Gender
Male
HSC
2011
Pasture disproved the theory of "spontaneous generation" and developed the process of "pasturization" which eliminated microflaura from substances.

coined terms aerobic and anaerobic

-unwittingly provided evidence for the germ theory

Pasture developed a method of determining the cause of disease in "kochs postulates"

-gave evidence for/proved the germ theory

Explain the "first line of defeanse" of the human body
Explain? :S

Anyways i'll just blabber on about something:

The first line of defence has skin, cilia hairs, mucous membranes and other chemicals which prevent the entry of pathogens. It is non-specific.
 

memo15

Member
Joined
Aug 2, 2011
Messages
142
Gender
Female
HSC
2012
1st line of defence is non specific defence and includes:
Skin- skin is a tough outer barrier of the body and contains keratin wich can not be penetrated unless the skin is broken. Skin has its own population osf harmless bacteria that prevent pathogens from enetering. Sebecous glands in the skin release sebum which is broken down by the bacteria to create an acidic env for the pathogens therefore destroy pathogens
Mucus: mucus lines the digestive and respiratory and reproductive tracts. It is sticky and therefore traps the pathogens and dust .. it contains Iga which destroys the pathogens
Cilia: tiny hair like projections that beat and sweep mucus to be coughed out or swallowed
 

darkccc

New Member
Joined
Mar 13, 2009
Messages
8
Gender
Undisclosed
HSC
N/A
Anyone mind giving any tips on how to tackle the 6-8 marker questions? I always lose marks here and there in them...
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top