HSC Biology Marathon 2015 (1 Viewer)

[BlueGas]

I'm surprised there hasn't been a Biology Marathon thread yet, and why not create one? So let me start off this thread with a beautiful biology question.

Outline a current technology to allow the measurement of oxygen saturation in the blood. (3 marks)

 

[DepressedPenguino]

A pulse oximeter is an instrument that can be used to measure the oxygen saturation levels in the blood. It can be clipped onto a finger and, by passing a beam of infrared light through the finger, the amount of infrared light absorbed can be used to measure the saturation level of harmoglobin and thus the oxygen saturation level. The oxygen saturation level is delivered as a percentage.

 

[DepressedPenguino]

Question: how are stem cells produced in our body?

 

[BlueGas]

Question: how are stem cells produced in our body?

Cell differentiation and speacilisation: is a process in which different genes are activated in different cells, creating the specific proteins that give a particular cell type its character, usually in un-speacilised cells (ie stem cells) which develops into a specific type of cell in response to specific triggers from the body or the cell itself. It then develops to a certain shape and produces only certain proteins so that it does a certain job

 

[BlueGas]

Cell differentiation and speacilisation: is a process in which different genes are activated in different cells, creating the specific proteins that give a particular cell type its character, usually in un-speacilised cells (ie stem cells) which develops into a specific type of cell in response to specific triggers from the body or the cell itself. It then develops to a certain shape and produces only certain proteins so that it does a certain job

I feel like my answer is incorrect, anyone know the correct answer?

 

[astab]

That's correct. But stem cells are produced in the bone marrow and mature and differentiate to form other cells eg. Neurons, skin cells, etc. Specialisation is the role carried out by each cell

 

[astab]

Does anyone know the dependent and independent variables in the following experiments:

1. The effect of CO2 on pH - our school blew into water and added universal indicator to observe the change in pH. As expected, it went from neutral to slightly acidic.

2. Modeling natural selection - our teacher put some chemical (something you put on nails) on a jellybean of one colour and left the other ones as normal. Once everyone knew which colour contained the chemical, they avoided it when picking out jellybeans and chose other colours. After the fourth round of jellybeans, the blue ones were left behind while all the other ones had been eaten.

 

[BlueGas]

Does anyone know the dependent and independent variables in the following experiments:

1. The effect of CO2 on pH - our school blew into water and added universal indicator to observe the change in pH. As expected, it went from neutral to slightly acidic.

2. Modeling natural selection - our teacher put some chemical (something you put on nails) on a jellybean of one colour and left the other ones as normal. Once everyone knew which colour contained the chemical, they avoided it when picking out jellybeans and chose other colours. After the fourth round of jellybeans, the blue ones were left behind while all the other ones had been eaten.

1. The dependent variable is the pH level and the independent variable is the time spent blowing CO2 into the water

2. This one is kind of weird, but since the independent variable is the one which when changed changes the dependent variable, the independent variable should be the chemicals on the blue jelly bean since it changes the number of the other jelly beans and the dependent variable will be all other jelly beans.

 

[DepressedPenguino]

i agree with bluegas

 

[DepressedPenguino]

That's correct. But stem cells are produced in the bone marrow and mature and differentiate to form other cells eg. Neurons, skin cells, etc. Specialisation is the role carried out by each cell

thank you

 

[BlueGas]

Question: What chemicals are filtered out of the blood by the kidney and what chemicals are reabsorbed into the blood by the kidney?

 

[astab]

thank you

No worries

 

[astab]

Question: What chemicals are filtered out of the blood by the kidney and what chemicals are reabsorbed into the blood by the kidney?

Substances that filter into the glomerulus must be small enough to filter through. They include urea, water, solutes, ions, amino acids and glucose. Essential metabolites (solutes, ions, amino acids and glucose) are reabsorbed. They are actively pumped back into the blood vessels at the descending loop of Henle and distal tubules. Water inadvertently follows this change in solute concentration and moves into the blood vessel by osmosis (to maintain the concentration gradient at the blood vessel).

 

[astab]

1. The dependent variable is the pH level and the independent variable is the time spent blowing CO2 into the water

2. This one is kind of weird, but since the independent variable is the one which when changed changes the dependent variable, the independent variable should be the chemicals on the blue jelly bean since it changes the number of the other jelly beans and the dependent variable will be all other jelly beans.

Thanks

 

[Fiction]

Question: What chemicals are filtered out of the blood by the kidney and what chemicals are reabsorbed into the blood by the kidney?

I've always wondered what chemicals allude to in this situation lol - like is water considered a chemical?

Brain dump~
As blood passes through the glomerulus in the bowman's capsule water, minerals, salts, vitamins, urea and glucose are filtered out by passive transport. Glucose is then reabsorbed back into the blood at the proximal tubule. In the descending arm of Henle's loop, water moves out by osmosis and urea moves in by diffusion. In the ascending loop of Henle, salt moves out of the tubule as aldosterone acts by increasing permeability of blood vessels to salt. Likewise, in the distal tubule and collecting tubule, water moves out (distal and collecting) as anti-diuretic hormone acts by increasing permeability to water. Some selective reasborption of hydrogen and potassium ions will occur in the distal tubule to regulate the concentration of pH and salts.

 

[astab]

What about comparing the advantages and disadvantages of artificial blood compared to donated blood. If you were asked to evaluate the uses of one over the other, how many advantages and disadvantages would be enough to earn, say, 6/6 assuming it's a six marker. What other advantages and disadvantages are there other than examples below:

-can be stored at room temperatures and are easily transportable
-perfluorocarbons (a type of artificial blood) is seventy times smaller than a standard red blood cell and can squeeze through narrow blood vessels, delivering oxygen to respiring cells
-they can be mass produced cheaply
-they are unspecific in blood type
-they can be sterilised, which lowers the spread of blood-transmitted diseases

-while they have long shelf-lives, red blood cells can last for up to 40 days longer than artificial blood
-more research is needed
-haemoglobin-based oxygen carriers can emulsify in blood, which increases blood viscosity and lowers blood flow/pressure
-they can also oxidise, leading to blood poisoning


Any other disadvantages?

 

[Fiction]

I'm surprised there hasn't been a Biology Marathon thread yet, and why not create one? So let me start off this thread with a beautiful biology question.

Outline a current technology to allow the measurement of oxygen saturation in the blood. (3 marks)

An oximeter is used to monitor oxygen saturation in blood in patients who are undergoing surgery, asthmatics who may have trouble breathing or pre-mature babies. The technology is quick to set up and painless to apply and involves attaching a peg-like instrument to either the patient's finger, toe or earlobe. The peg has two light emitting diodes and one photo detector. It works through the principle that oxyhaemogloblin and haemogloblin without oxygen attached each absorb very different amounts of red light where it measure the transmission of light from the diode to the photo detector. An electrical component then processes the information to provide a reading of the oxygen saturation in percentage form, where oxygen saturation should read either above or equal to 95%.

 

[Fiction]

What about comparing the advantages and disadvantages of artificial blood compared to donated blood. If you were asked to evaluate the uses of one over the other, how many advantages and disadvantages would be enough to earn, say, 6/6 assuming it's a six marker. What other advantages and disadvantages are there other than examples below:

-can be stored at room temperatures and are easily transportable
-perfluorocarbons (a type of artificial blood) is seventy times smaller than a standard red blood cell and can squeeze through narrow blood vessels, delivering oxygen to respiring cells
-they can be mass produced cheaply
-they are unspecific in blood type
-they can be sterilised, which lowers the spread of blood-transmitted diseases

-while they have long shelf-lives, red blood cells can last for up to 40 days longer than artificial blood
-more research is needed
-haemoglobin-based oxygen carriers can emulsify in blood, which increases blood viscosity and lowers blood flow/pressure
-they can also oxidise, leading to blood poisoning


Any other disadvantages?

The main one I learnt, personally wasn't haemogloblin but perflurochemicals

Artificial blood can be advantageous over real blood as there is a shortage of real blood, a need for real blood to be cross-matched as certain blood types reject blood from other blood types due to the antigen contained within red blood cells, a need for there to be an absence of infectious agents and lastly as artificial blood often have a longer shelf life than real blood (e.g Perflurochemicals last for 12 months compare to real blood which has a shelf-life of around 3 months).

An example of artificial blood is Perflurochemicals. It is completely sterile and disease-free as it does not contain any biological materials, it has a longer shelf life than real blood of approximately 8 more months, it can be stored at room temperature hence making it suitable to be transported conveniently in emergency vehicles such as ambulances, furthermore perflurochemicals can be used universally with all blood types, is cheaper to produce compared to using real blood, is able to dissolve 5 times more oxygen than real blood. An example of Perflurochemicals is Oxycyte TM which is currently under trial.

Disadvantages associated with perflurochemicals include that it's around 70x smaller than real blood, hence allowing it to pass through places where real blood would not normally be able to travel in, it's need to be mixed with lipids to form an emulsion that can be mixed with blood and how it can only be used to replace the function of Red blood cells, essentially, as perflurochemicals are not able to act as disease-fighting instruments, such as white blood cells are, nor are they able to act as clotting agents, like platelets.

Therefore, although real blood is disadvantageous over artificial blood in it's cost-efficiency, artificial blood with current technology, is not able to fully replace all functions of real blood, and because of it's size, may affect metabolic processes in the body.

 

[Fiction]

Describe one current theory responsible for the processes which involve movement of materials in plants in either xylem or phloem tissue (3 marks)

 

[BlueGas]

Describe one current theory responsible for the processes which involve movement of materials in plants in either xylem or phloem tissue (3 marks)

The cohesion-adhesion-tension theory is responsible for the movement of water in the xylem. The constant loss of water leads to a transpiration stream (constant upward flow of water through a plant), this is because of waters two properties: Adhesive forces (when water molecules attach to the walls) and cohesive forces (when water molecules attach to each other), hence leading to the capillarity and hence the stream.