Honors Biology - Unit 5: Check & Challenges

Photorespiration

________ occurs when oxygen replaces carbon dioxide in a reaction; only one molecule of PGA and one molecule of the 2- carbon acid glycolate.

Metabolic activity

________ is most accurately expressed as a rate because it makes things easier to measure the amount of carbon dioxide used in the process as a rate.

Photosynthesis

________ is essential to life on Earth by allowing photoautotrophs to use sunlight energy to turn carbon dioxide into sugars for fuel.

O2

________ does not inhibit photosynthesis in C4 plants; they can still function.

deep earth bacteria

Some ________ consume petroleum or natural gas.

fuel

Photosynthesis is essential to life on Earth by allowing photoautotrophs to use sunlight energy to turn carbon dioxide into sugars for ________. The ________ helps living organisms survive and grow.

behavior of the bacteria

Explain. What is a clue that these organisms are chemoautotrophs? Answer with a single words or term.

Chemoautotrophs

________ obtain organic nutrients by fixing carbon dioxide, usually with the Calvin cycle.

Photosynthetic organisms

Why are ________ called producers in an ecosystem. ________ are called producers in an ecosystem because the photoautotrophs produce their own food, and therefore become food sources for other organisms.

high levels of oxygen

Relatively ________ are favored conditions for photosynthesis.

Glycolate

Photorespiration occurs when oxygen replaces carbon dioxide in a reaction; only one molecule of PGA and one molecule of the 2- carbon acid ________. ________ is transported out of the chloroplast and partially broken down into carbon dioxide.

Carbon dioxide

________ is thus delivered effectively to the bundle- sheath cells, favoring photosynthesis and inhibits photorespiration.

products of the Calvin cycle

The ________ are six molecules of PGAL, or three- carbon sugars.

products of the light reactions

The ________ are ATP, NADPH, and oxygen gas (chemical energy)

O2

Conversely, ________ can inhibit photosynthesis in C3 plants.

Chemoautotrophs

________ obtain energy by oxidizing inorganic substances (also known as electron sources), such as iron, sulfur, and various other minerals.

Carbon dioxide

________ is combined with a 3- carbon acid, the resulting 4- carbon acid is rearranged and then transported to the bundle- sheath cells, where ________ is released from the 4- carbon acid and refixed by rubisco which forms PGA through the Calvin cycle.

Chemoautotrophs

________ are rare among familiar organisms because many of them must oxidize large quantities of inorganic material to obtain enough energy in order to survive.