Kaplan Bio Q's

[ddasung]

I have Kaplan's midterm and final, but don't have the answers. Can someone help me with a few questions I have?

#13 from the midterm,

A capillary has

A. a higher hydrostatic pressure at the arteriole end and a lower hydrostatic pressure at the venue end.
B. a higher osmotic pressure in its bolld plasma than the osmotic pressure of the interstitial fluid bathing the tissues.
C. a hydrostatic pressure that results from the beating of the heart.
D. A and C
E. A, B, and C

---- Can someone point out the difference between hydrostatic pressure and osmotic pressure? Aren't they both referring to water pressure?

#18 from the midterm,

Birds nesting in trees are examples of which of the following types of symbiotic relationships?

A. parasitism
B. Commensalism
C. Mutualism
D. Predation
E. None of the above

#35 from the midterm,

In the northerm hemisphere, to go from a coniferous forest ecosystem to a tundra ecosystem, you can travel:

A. upwasrd in altitude only.
B. upward in altitude and southwards in direction.
C. northwards in direction only.
D. downwards in altitude and southwards in direction.
E. upwards in altitude and northwards in direction.

--- I really don't like this type of question. Why do we have to know? Those of you who took DAT, did you have any questions relating to the climate?

#11 from the final,

Which of the following is involved in respiration and excretion, and develops into the placenta in humans?

A. chorion
B. allantois
C. amnion
D. yolk sac
E. placenta

--- Isn't chorion develops into the placenta? But, isn't it the allantois that have the blood vessels which develops into umbellical cords and is involved in respiration and excretion?


Thank you so much for your time and support.

 

[UBTom]

Hi Ki-Yoon,

#1: There is a very big difference between hydrostatic pressure and osmotic pressure. Hydrostatic pressure is basically a mechanical pressure, such as that applied by the heart as it mechanically squeezes the blood out of the ventricles to force it through your systemic circulation. Osmotic pressure is generated on the other hand by a chemical/concentration gradient-- For example, if you have liver disease and it could not produce enough albumin for circulation in your blood, your blood osmotic pressure would be very low (i.e. not enough solute). Water would rush out of your blood and into the interstititial spaces until the osmotic pressure equilibrates, and cause generalized edema (you would look swelled and puffy). You will learn just how critical the difference is between hydrostatic and osmotic pressure in dental school (very important for diagnosis!!)

#2 is poorly worded I think... With some birds it can be parasitism like woodpeckers that kill some trees. With other birds who does nothing to the trees but hang twig nests on a branch it would be commensalism. And with yet other birds which eat insects that destroys trees, it's mutualism! That question is very badly worded indeed.

#3: Upwards and northwards. As you get nearer the poles the environment gets more like a tundra. This is also true if you climb mountains-- The higher you go, it gets more like tundra (like when you climb Everest!).

#4 The Chorion does indeed develop into the placenta, and is the site where nutrients, O2 and waste products diffuse from and to the mother, so it is also intimately involved with the fetus's respiration and excretion.

Hope this helps!