EOC Wednesday #2

Plant cells can synthesize energy-rich organic molecules and later break them down to extract that energy for performing life processes. These activities require direct interaction between the

• chloroplasts and vacuoles

• cell walls and ribosomes

• chloroplasts and mitochondria

• ribosomes and mitochondria

Starch molecules present in a maple tree are made from materials that originally entered the tree from the external environment. What form are these materials in before entering the tree?

• enzymes

• simple sugars

• amino acids

• inorganic compounds

An enzyme known as rubisco enables plants to use large amounts of carbon dioxide. This enzyme is most likely active in the

• nucleus

• mitochondria

• vacuoles

• chloroplasts

Plants in areas with short growing seasons often have more chloroplasts in their cells than plants in areas with longer growing seasons. Compared to plants in areas with longer growing seasons, plants in areas with shorter growing seasons most likely

• make and store food quickly

• have a higher rate of protein metabolism

• grow taller

• have a different method of respiration

Leaves of green plants contain openings known as stomates, which are opened and closed by specialized cells allowing for gas exchange between the leaf and the outside environment. Which phrase best represents the net flow of gases involved in photosynthesis into and out of the leaf through these openings on a sunny day?

• carbon dioxide moves in; oxygen moves out

• carbon dioxide and oxygen move in; ozone moves out

• oxygen moves in; nitrogen moves out

• water and ozone move in; carbon dioxide moves out

Eating a sweet potato provides energy for human metabolic processes. Which is the original source of this energy?

• protein molecules stored within the potato

• starch molecules absorbed by the potato plant

• the sun through photosynthesis

• vitamins and minerals found in the soil

Some sea slugs store chloroplasts obtained from algae they have ingested. The chloroplasts continue to carry out photosynthesis within the slugs. What advantage would this activity be to these sea slugs?

• The slugs with chloroplasts can synthesize some of their own food.

• The slugs with chloroplasts no longer need to carry out respiration.

• The chloroplasts provide the slugs with camouflage that protects them from UV radiation.

• The chloroplasts contain enzymes that allow the slugs to digest starch.

The cells of some organisms contain both chloroplasts and mitochondria. Which statement describes what would happen in these cells if they were moved from a light environment to a dark one?

• The amount of oxygen present would decrease and the amount of carbon dioxide would increase.

• The amount of glucose present would increase and ATP would no longer be available.

• The amount of carbon dioxide present would decrease and ATP would continue to be synthesized.

• The amount of oxygen present would increase and the amount of glucose available would decrease.

Chlorophyll gives plants their green color. Chlorophyll is produced only when plants are exposed to light, so plants kept in darkness have no chlorophyll and appear white. The best explanation for this is that

• chlorophyll is not needed by green plants at night

• darkness mutates the chlorophyll genes, causing them to produce a white color

• light is required for chlorophyll genes to be expressed

• genetic information in cells is not influenced by the outside environment.

A scientific study showed that the depth at which algae were found in a lake varied from day to day. On clear days, the algae were found as much as 6 meters below the surface of the water but were only 1 meter below the surface on cloudy days. Which hypothesis best explains these observations?

• Light intensity affects the growth of algae

• Wind currents affect the growth of algae

• Nitrogen concentration affects the growth of algae

• Precipitation affects the growth of algae.