Download Answers to exam questions on Chloroplasts and

Answers to exam questions on Chloroplasts and Photosynthesis
Question Six: Chloroplasts
Discuss the role of chloroplasts in relation to other cell organelles and the
overall functioning of the cell.
Role =
Chloroplasts carry out the process of photosynthesis, which traps light energy,
to split water; the hydrogen is combined with carbon dioxide to produce
glucose. Oxygen is produced as a waste product.
Relation to other cell organelles (mitochondria) =
The glucose produced by the chloroplasts is used by mitochondria in the
process of respiration, which produces ATP.
Overall functioning of the cell =
Other organelles use this ATP to carry out cell activities when they require
energy, such as the cell membrane which uses ATP as an energy source
when ions are actively pumped into or out of the cell.
Question Seven: Bottled plants
Discuss why the plants did not grow in the sealed bottle but did after the lid
was removed.
 Sealed bottle is a closed envt – water, nutrients, oxygen and carbon
dioxide are only available in constant amounts.
 Plant uses carbon dioxide in p/s (p/s releases oxygen)
 Oxygen is used in respiration, which releases carbon dioxide
 Plant unable to grow because not enough carbon dioxide available for
it to make extra chemicals needed for it to increase its body size (grow)
 When jar opened, amount of carbon dioxide available increases and
there is now sufficient amounts available for respiration and growth.
 Extra glucose from p/s is changed into chemicals(such as DNA and
cellulose) needed to make more cells for growth to occur.