Unit 6: Photosynthesis

Question 1

What is the ancestor of all plants? Why?

Answer 1

Algae. It photosynthesizes, lives in the ocean, and can be a protist.

Question 2

What are the reactants of photosynthesis?

Answer 2

Carbon dioxide and water

Question 3

What causes global warming (climate change)

Answer 3

Excess CO2. CO2 is released whenever we burn fossil fuels like gas, coal or oil. CO2 is a greenhouse gas. Too much CO2 will trap too much heat and warm the earth, just like too many blankets would make you too hot.

Question 4

Why are plants green?

Answer 4

White light contains all colors. When white light hits a plant, the chlorophyll will absorb all of the colors except for green (and some yellow), which will bounce of the plant and go to your eye.

Question 5

Why do some leaves turn colors in the fall?

Answer 5

Some plants stop photosynthesizing for the winter, so they stop making chlorophyll. The plants’ remaining pigments don’t absorb red, orange, or yellow.

Question 6

What does the waxy layer do?

Answer 6

Prevents water from evaporating out of the leaf.

Question 7

What do the stomata and guard cells do?

Answer 7

The stomata are holes that allow air to flow into and out of the bottom of a leaf. CO2 goes in and O2 leaves. Guard cells close the leaf to conserve water when the plant is dry or not photosynthesizing.

Question 8

Describe CO2’s journey in a leaf

Answer 8

CO2 flows into the leaf through the stomata. Once inside, it diffuses into the cells of the spongy layer. Photosynthesis connects 6 CO2s making glucose. The plant will later burn the glucose for energy and release the CO2 again.

Question 9

What is food for plants?

Answer 9

Glucose (It is the building block and provides energy)

Question 10

Where does most of the mass of a plant come from?

Answer 10

Most mass comes from CO2 and then H2O. Very little comes from nutrients in the soil.

Question 11

Why are plants good for reducing global warming?

Answer 11

Plants take in CO2 during photosynthesis, reducing this greenhouse gas.

Question 12

What are the products of Photosynthesis?

Answer 12

Glucose (food for plants) and Oxygen (a waste product for plants)

Question 13

What are the inputs of Photosynthesis?

Answer 13

Water and Carbon dioxide

Question 14

What happens to glucose after it is made?

Answer 14

Cells use facilitated diffusion to move glucose through the phloem and to an area of storage like fruit or tubers (roots like potatoes or carrots).

Question 15

What are the 4 steps of photosynthesis

Answer 15

Photolysis, Electron transport chain, Calvin cycle, and Glucose formation

Question 16

Honors: What happens during the first step of photosynthesis?

Answer 16

Photolysis- Energy from the sun is used to remove electrons from water and place them in the electron transport chain. H+ ions go into the thylakoid and Oxygen gas (a waste product) is made.

Question 17

Honors: What happens during the 2nd step of photosynthesis?

Answer 17

Electron transport chain: Unstable electrons move down the electron transport chain, using their lost energy to make NADPH and to pump H+ into the thylakoid. Concentrated H+ ions diffuse out; their energy is used to make ATP.

Question 18

Honors: What happens during the 3rd step of photosynthesis?

Answer 18

Calvin Cycle: Energy from ATP and NADPH is used to turn 6CO2s into 2G3P molecules. Energy is stored in the arrangement of atoms in G3P.

Question 19

Honors: What happens during the 4th step of photosynthesis?

Answer 19

Glucose formation: G3P molecules (contain 3 carbon atoms) are fused to make glucose (contains 6 carbon atoms).

Question 20

Describe Oxygen’s journey in a leaf

Answer 20

Oxygen is made during photosynthesis in the photosynthetic layer. It diffuses through the spongy layer and exits out the stomata.

Question 21

What is the purpose of photosynthesis?

Answer 21

The purpose of photosynthesis is to make glucose that the plant can later burn for energy. Glucose can also be used as a building block in the plant.

Question 22

What is the photosynthesis equation?

Answer 22

In words: Water and Carbon dioxide react to form glucose and Oxygen

In symbols: