Biology 2013ers MARATHONN (4 Viewers)

[Omed62]

Homeostasis is the process in which organisms maintain a stable internal environment

Question: explain the negative feedback mechanism

Negative feedback mechanism works just like a switch mechanisms. for example, if an organisms body temperature rises to a extreme edge. The signal detects the rise of temperture and snds a signal to the hypotheramus in the brain, which acts to responed to the temperature rise by lowing the temperture.

* The normal body temperture of an orgaism is 37*C and any change in their temperture, will send a signal to the hypotheramus in the brain.
* The hypotheramus will then responed to the change, to maintain a constant internal body temperture.

Normal temp 37*C ------Temp rises-------signal to Hypotheramus ------ Hupotheramus detects the change----- tempterature lowers abck to 37*C ---

I hope you guys find it useful... hey if you need any help regarding notes or anything else PM.

Thanks

 

[Omed62]

Describe active transport and reabsorption as alternative methods of removing nitrogenous wastes

Oright Bio genius is in the house, throw in any question guys!!!

OK!!!

Active transport:

* Nitrogenous wastes are toxic substances, if they accumulate in the body, they cause serious toxication to cells, which may kill them.

Active transport requires expending of energy thats acts as an alternative method to remove any nitrogenous wastes, to ensure maximame survival advantage for the cells.

By reaborsption, the body regulates by abosrbing some nutrients and reasling the toxic substances to the urea to be emptyed.

 

[fionarykim]

Explain the pressure flow mechanism, or source to sink system that occurs in phloems

Ahh im so bad at this, but i'll give it a go
This is also known as translocation
The glucose and products of photosynthesis are actively loaded into the phloem (known as the source). Therefore the concentration of solutes there would be higher, causing water to move in via osmosis. This causes an area of high water pressure which then forces the glucose molecules along the phloem until it reaches a growing tip or area of the plant which requires this glucose and is unloaded and used /stored (sink)

Define enantiostasis, why is it important for organisms to maintain appropriate salt concentrations?

 

[fionarykim]

might try and get this up and running again ...

How does the segregation of chromosomes during meiosis lead to a wide variety
of gametes being produced?

 

[JT145]

inb4ObliviousNinja

 

[ocatal]

might try and get this up and running again ...

How does the segregation of chromosomes during meiosis lead to a wide variety
of gametes being produced?

During meiosis a wide variety of gametes are produced as a result of the random segregation and independent assortment of chromosomes. The chromosomes in each homologous pair randomly separate where one entire chromosome of each pair moves into a daughter cell during the first meiotic division. In addition, the homologous pairs (i.e. of maternal and paternal) do not necessarily assort into the same gamete, but rather assort independently, further increasing genetic variation as a result of the production of a wide variety of genetically unique gametes.

Some individuals argue that renal dialysis over one's lifetime is far more beneficial than a single kidney transplant. Justify this claim.

 

[fionarykim]

okay i have no idea how to answer that
someone help? LOOL

 

[ocatal]

okay i have no idea how to answer that
someone help? LOOL

Haha no problem. Basically its a combination of a few dot points. So you would mention the advantages and disadvantages of renal dialysis (e.g. It enables individuals with kidney problems to be able to excrete wastes. Despite this, dialysis does not allow for re-absorption of fundamental substances). Then you would mention the advantages and disadvantages of an organ transplant (e.g. Its done only once, however, continuous use of immunosuppressants is required which weaken the immune system and make the individual prone to other, more dangerous diseases) and show that renal dialysis is far more beneficial then a kidney transplant.

Using a specific example from your studies, describe the relationship between gene expression and the maintenance and repair of body tissues.

 

[jacksonhughes95]

Enantiostasis is the maintenance of metabolic and physiological functions in response to variations in the environment. It is essential for organisms in estuarine environments to cope with fluctuations in salt levels due to changes in tides. For example, in high saline environment - when sea tides are high - mangroves must excrete the excess salts via special glands in the leaves and discarding leaves when there is an accumulation of salts.

 

[jacksonhughes95]

QUESTION: justify, including specific examples, why active and passive transport are needed in the processes of filtration and reabsorption.

 

[fionarykim]

QUESTION: justify, including specific examples, why active and passive transport are needed in the processes of filtration and reabsorption.

hmm well, simply passive transport is not sufficient in the processes of the kidney for a few reasons
-passive transport is too slow and inefficient as it is controlled by the concentration gradient
-passive transport is non selective and therefore cannot select the substances which is required to be reabsorbed
-Osmosis only deals with water and not with wastes

therefore active transport is also required for reabsorption to, actively reabsorb substances we require such as glucose, nutrients and ions back into the bloodstream.

anyone want to add to that?

Explain two changes in chemical composition of blood as it moves along a capillary

 

[leesh95]

Passive transport is useful up to a certain point since active transport requires energy. If we were to only use active transport then it would require a lot of energy, thus we use them both in conjunction to achieve our purpose.

 

[leesh95]

-A decrease in oxygen levels since hemoglobin releases its oxygen and O2 deprived cells take it up for respiration
-An increase in CO2 levels which diffuses into the blood from across the capillary walls.

 

[obliviousninja]

I never got this.

Explain how the processes of filtration and reabsorption in the mammalian nephron regulate body fluid composition

 

[Menomaths]

I never got this.

Explain how the processes of filtration and reabsorption in the mammalian nephron regulate body fluid composition

filtration occurs in bowmans capsule in the bowman's capsule. it doesn't absorb the big stuff like rbc's but it absorbs glucose and the ions Na+ and K+ which are important. If these weren't reabsorbed in some stage in the nephron then you'd have some sort of deficiency as your pissing out the good stuff so there's the distal tubule and other tubules which reabsorb all the good things like the ions and glucose. If you're dehydrated then the big tubule can't remember it's name atm becomes more permeable by the release of Na+ which reabsorbs more water.

 

[fionarykim]

LOL as if you never got that mr first in bio
okay idk if im answering correctly
but basically
-filtration: process where most of the components in the blood plasma is filtered out of the bloodstream into the nephron via the glomerulus. Not all substances are filtered through, blood cells and other bigger proteins are left in the blood.
Reabsorption of required substances such as nurtrients, glucose and water occurs in the proximal tubule, where these substances are actively moved back into the blood vessels, urea remains in the nephron.
if recquired to maintain more water, more water can be reabsorbed in the collecting duct and loop of henle.

therefore Filtration and reabsorption regulate body fluid composition by preventing the loss of useful substances and filtering out toxic ones, controlling which substances remain in the body and which ones are removed

discuss the role of quarantine in preventing the spread of disease and plants and animals into Austracross regions of Australia

 

[ocatal]

LOL as if you never got that mr first in bio
okay idk if im answering correctly
but basically
-filtration: process where most of the components in the blood plasma is filtered out of the bloodstream into the nephron via the glomerulus. Not all substances are filtered through, blood cells and other bigger proteins are left in the blood.
Reabsorption of required substances such as nurtrients, glucose and water occurs in the proximal tubule, where these substances are actively moved back into the blood vessels, urea remains in the nephron.
if recquired to maintain more water, more water can be reabsorbed in the collecting duct and loop of henle.

therefore Filtration and reabsorption regulate body fluid composition by preventing the loss of useful substances and filtering out toxic ones, controlling which substances remain in the body and which ones are removed

discuss the role of quarantine in preventing the spread of disease and plants and animals into Austracross regions of Australia

Quarantine is a strategy used to control the spread of disease by minimising the risk of pests and diseases entering Australia. Animal and plant quarantine involves sending plants and animals that come into Australia to special quarantine stations where they are analysed for any signs of exotic diseases. This minimises the risk of entry of diseases into the country. Additionally, border control involves the inspection of prohibited material in order to prevent the entry of plant and animal diseases. Consequently, quarantine measures are generally effective in preventing the spread of diseases into Australia.

Outline the reasons why Mendel's work was not recognised until some time after it was published.

 

[obliviousninja]

LOL as if you never got that mr first in bio

Haven't you heard about my kidney practical incident?

http://community.boredofstudies.org/showthread.php?t=306856&p=6394090&highlight=kidney#post6394090

 

[Menomaths]

discuss the role of quarantine in preventing the spread of disease and plants and animals into Austracross regions of Australia

Quarantine prevents the spread of pathogens, organisms which are a potential threat to Australian plants, animals and people. Due to the effective measures taken by the AQIS the spread of such organisms has been substantially reduced, an example of this is the Mad Cow's Disease which affected a great proportion of UK and the countries supplied by them however Australia put a strict ban on the transportation of livestock from UK which resulted in Australia not getting affected by the Mad Cow's Disease. Also, there has been strict measures to control the spread of fruit flies within Australia which has resulted in certain cities being free of fruit flies.

 

[Menomaths]

Quarantine is a strategy used to control the spread of disease by minimising the risk of pests and diseases entering Australia. Animal and plant quarantine involves sending plants and animals that come into Australia to special quarantine stations where they are analysed for any signs of exotic diseases. This minimises the risk of entry of diseases into the country. Additionally, border control involves the inspection of prohibited material in order to prevent the entry of plant and animal diseases. Consequently, quarantine measures are generally effective in preventing the spread of diseases into Australia.

Outline the reasons why Mendel's work was not recognised until some time after it was published.

Low profile, monk. Wasn't well known. Scientific community's attention was diverted somewhere else, Theory of Evolution. His article wasn't published in more commonly read journals. Only a few people read his article.
can't be bothered constructing proper sentences lol sorry