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Living Environment Regents June 2006 Question 21 PDF Print E-mail
NYS Living Environment Regents June 2006

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Correct Answer: Option 3 Guard cells change the size of leaf openings, regulating the exchange of gases.

The guard cells regulate the stomata, which are microscopic holes in a plant leaf which allows gases to enter and leave and water vapor to leave as well. The ability of the guard cell to close during periods of limited water availability for the plant allows the plant to maintain water homeostasis. This is an example of feedback mechanism in plants. A feedback mechanism occurs when the level of one substance influences the level of another substance or activity of another organ.   Option 4 states about respiration, which is not a feedback mechanism of plants.

Option 2 is incorrect. Oxygen is a product of photosynthesis. Therefore, if there is decreased rate of oxygen, less oxygen will be also produced by the chloroplast. Carbon dioxide, not nitrogen, is used up by the chloroplast during photosynthesis. Thus, option 1 is incorrect.

 
Living Environment Regents June 2006 Question 03 PDF Print E-mail
NYS Living Environment Regents June 2006

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Correct Answer: Option 3 low concentration→ high concentration (ATP used)

Active transport is the mediated process of moving particles across a biological membrane against a concentration gradient. Active transport uses energy, unlike passive transport, which does not use any energy. ATP, a form or chemical energy, is needed for this process to take place. Indeed, this setup is an active transport. Since it uses chemical energy, it is termed as primary active transport. If electrochemical gradient was used in the process, it is called secondary active transport.

Option 1 is incorrect because no energy is needed to move particles from high concentration to low concentration. Since there is no energy or ATP (adenosine triphosphate) needed for the process to happen, it is a passive transport.

Option 2 is incorrect. Just like option 1, no energy or ATP was used in the process therefore it is a passive transport.

Option 4 is incorrect. ATP is needed in order to transport particles from low to high concentration.

 
Living Environment Regents June 2007 Question 64 PDF Print E-mail
NYS Living Environment Regents June 2007

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Correct Answer: Option 1 More oxygen is delivered to muscle cells

Various exercises require a predominance of certain muscle fiber utilization over another. Aerobic exercise involves long, low levels of exertion in which the muscles are used at well below their maximal contraction strength for long periods of time. Aerobic exercise, which rely primarily on the aerobic (with oxygen) system, use a higher percentage of Type I (or slow-twitch) muscle fibers, consume a mixture of fat, protein and carbohydrates for energy, consume large amounts of oxygen and produce little lactic acid.

Exercise has no direct effect on the rate of blood cell excretion, rate of digestion, and hormone production.

 
Living Environment Regents June 2007 Question 55 PDF Print E-mail
NYS Living Environment Regents June 2007

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Correct Answer: Option 2 a feedback mechanism

It is a negative feedback mechanism. This is the special mechanism for turning the hormones off after they have done their job. When the blood sugar level drops, the amount of insulin produced also falls, and when blood sugar level has risen back to normal, the amount of adrenalin and glucocorticoids falls.

 
Living Environment Regents June 2008 Question 70 PDF Print E-mail
NYS Living Environment Regents June 2008

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If you are going to be exercising for more than a couple of minutes, your body needs to get oxygen to the muscles or the muscles will stop working. Just how much oxygen your muscles will use depends on two processes: getting blood to the muscles and extracting oxygen from the blood into the muscle tissue. Your working muscles can take oxygen out of the blood three times as well as your resting muscles.

Correct Answer: Option 1

 
Living Environment Regents June 2008 Question 64 PDF Print E-mail
NYS Living Environment Regents June 2008
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Correct Answer: Guard cells surround stomata in leaves and control the size of the hole. By reducing the size of the hole, less water vapor is able to escape and vice-versa. Varying the size of the stomata over time allows the plant to remain at a relatively constant hydration level.

One Function regulated by guard cells in leaves
– Exchange of gases

Guard cells change the size of the leaf opening to control the exchange of water vapors


One possible evolutionary advantage of the position of the guard cells on the leaves of land plants – prevents excess evaporation of water on sunny days
 
Living Environment Regents June 2008 Question 59 PDF Print E-mail
NYS Living Environment Regents June 2008
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Correct Answer: The human body will produce anti bodies to destroy the pathogens
 
Living Environment Regents June 2008 Question 57 PDF Print E-mail
NYS Living Environment Regents June 2008

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Correct Answer: The blood sugar level is the other indicator of decrease in the secretion of insulin.

When the blood sugar level increases beyond a standard count, it indicates that the insulin secretion has reduced.

 
Living Environment Regents June 2008 Question 56 PDF Print E-mail
NYS Living Environment Regents June 2008
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Correct Answer: In the human body the source of insulin is the pancreas.
 
Living Environment Regents June 2008 Question 55 PDF Print E-mail
NYS Living Environment Regents June 2008

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Correct Answer: When a virus infects humans, the relationship that exists between virus and humans is that of parasite and host.

The virus uses the human body cells to dwell and grow; and eventually infect the other cells.

 
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