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Human biology questions

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Skidous:

--- Quote from: anotherworld2b on July 23, 2016, 09:54:20 pm ---I will rewrite my response following your advice:D
I just wanted to put all the information I've received in one place before I lose track of what to include :)
I really appreciate all the help I've received :D

--- End quote ---

No problem anotherworld2b, that's a good way to get started in bio since it's such a content heavy subject, looking forward to marking the response

See ya soon
Skidous

anotherworld2b:

--- Quote from: Skidous on July 24, 2016, 12:26:39 pm ---No problem anotherworld2b, that's a good way to get started in bio since it's such a content heavy subject, looking forward to marking the response

See ya soon
Skidous

--- End quote ---

I've tried to rewrite my response :D
I hope its better

Q1. Absorption of nutrients depends on concentration differences so that substances diffuse across the absorbing surface. Explain how the concentration difference is maintained in the parts of the alimentary canal where absorption occurs.
 
The muscular movements of the intestinal wall constantly brings the villi into contact with different parts of the intestinal contents. These contents are constantly changing as new material is emptied into the small intestine from the stomach. In response to the constant influx of material from the consumption of food passive and active transport will diffuse material across the absorbing surface constantly to maintain the concentration difference.

The concentration difference in the small intestines is maintained by the active and passive transport of materials. Materials such as monosaccharides, amino acids, water soluble vitamins undergo active transport into the blood by using energy in the form of ATP. There is a high concentration of these materials in the blood and low concentration in the lacteal but ATP and active transport allows these materials to go against these concentration gradients.

The concentration difference in parts of the alimentary canal is also maintained by the passive transport of material following the concentration gradient. Water is diffused across the absorbing surface from high concentration in the lacteal to low concentration in the blood vessel by a process called osmosis. Other materials such as fat soluble vitamins, fatty acids and glycerol diffuse across the absorbing surface from high concentration in the lacteal to a lower concentration in the lymph vessel. These substances are then taken to the lymph nodes in the lymph to ensure that a low concentration of these nutrients is maintained in the lymph vessel of the villi in the small intestines.

Blood is part of the circulatory system which maintains the concentration difference of substances in the alimentary canal. Blood is constantly circulated around the body towards and away from organs allowing nutrients to be absorbed into organs and waste to be collected from the blood. New blood that flows through the blood vessel in the villi will prompt the transport of nutrients through passive transport, osmosis and active transport from the villi into the blood. As blood circulates the body constantly the nutrients that diffused into the blood will be taken to organs to be absorbed maintaining a constant concentration difference.

Skidous:
Hey anotherworld2b
This response was much better than before, all the information was there and it was much more coherent than the last one.

The response itself, however may be too long depending on the marks being allocated, so I think it may be beneficial to answer a question similar to this one but for less marks to work on making the answer more susinct but still coherent with the same amount of information.

Hope this helps
Skidous

anotherworld2b:

--- Quote from: Skidous on July 25, 2016, 05:38:27 am ---Hey anotherworld2b
This response was much better than before, all the information was there and it was much more coherent than the last one.

The response itself, however may be too long depending on the marks being allocated, so I think it may be beneficial to answer a question similar to this one but for less marks to work on making the answer more susinct but still coherent with the same amount of information.

Hope this helps
Skidous

--- End quote ---

Thank you for your help :D
I was wondering for this question could I get feedback on whether I am answering it correctly please :)

* Chapter 2 - Question 2

American Dr William Bean studied the growth of his fingernails for 35 years. He filed a horizontal line on his thumbnail just above the cuticle (the strip of skin at the base of the nail). By recording recording how long it took the mark to reach the tip of the thumbnail he was able to calculate the growth rate. He was eventually able to conclude:

‘A 35-year observation of the growth of my nails indicates the slowing of growth with increasing age. The average daily growth of the left thumbnail, for instance, has varied from 0.123mm a day during the first part of the study when I was 32 years of age to 1.1.95mm a day at the age of 67.’

Suggest a hypothesis that Dr Bean was testing
An increase in age will decrease the rate of the growth of nails

Which was the independent variable and which was the dependant variable in this investigation?
Independent variable: age
Dependent variable:  the growth of nails

List some of the variables that should have been controlled in Dr Bean’s study
-the size of the horizontal line each day he puts it on his thumbnail
-when he places the horizontal line
-where he places the horizontal line

Describe one source of random error in the investigation
An error in the accuracy of the measurement of the growth of the nail due to the measurement being calculated in millimeters,

Measure the length of your thumbnail. Assume that your thumbnail grows at the same rate as that of the 32-year-old Dr Bean. How long did it take the tip of your thumbnail to grow from the cuticle to its present position?
My nail: 12 mm. Dr Bean’s nail’s growth : 0.123mm.
12/ 1.123 = 97.56  so approximately 98 days

Do you think your fingernails and toenails grow at the same rate? Propose a hypothesis and outline an investigation that you could do to test your hypothesis
I do not think that fingernails and toenails grow at the same rate. I believe that fingernails grow at a faster rate than toenails.

Hypothesis: Over time fingernails will grow at a faster rate than toenails.

Method:
File a horizontal line on his thumbnail just above the cuticle (the strip of skin at the the base of the nail)
Measure the growth of each thumbnail and toenail everyday and record measurement
Record how long it took the mark to reach the tip of the thumbnail 
Calculate the growth rate
Repeat step 2-4 over a duration for 4 months 

Skidous:
Hey anotherworld2b

This question is a focus on experimental write-up, which is very easy to get a grasp of.
Your variables are correct but you could add a few more controlled variables such as diet, length of the experiment etc.

Your Hypotheses could be better though, the general structure would be If...(state the independent variable) then...(state the dependent variable) because (state reasoning)

For this example. If nail growth rate decreases with age then the rate of growth of the thumbnails should decrease over time because as the person ages, the metabolic functioning of the body begins to slow down until it stops. (that is due to the fact that all cells in the human body have a set amount of times they will divide before they die)

Your calculation is incorrect due to the fact that it is not written correctly (i did not pull out a calculator to test the result myself) it should be 12/0.123.

The method should be numbered, but the overall method is good.

It's an overall good attempt but can be made better in a few places, mainly in the Hypotheses written so try to improve on those.

Hope this helps
Skidous

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