2.9 Photosynthesis

Question 1

What is photosynthesis?

Answer 1

The process where carbon dioxide and water are converted into carbohydrates and oxygen using light energy.

Question 2

Where does photosynthesis occur in plant cells?

Answer 2

In chloroplasts, the organelles that capture light energy.

Question 3

What wavelengths of light are most effectively absorbed by chlorophyll?

Answer 3

Chlorophyll absorbs red and blue light most effectively and reflects green light.

Question 4

What is photolysis in the context of photosynthesis?

Answer 4

The stage of photosynthesis where water is split by light into hydrogen ions, electrons, and oxygen.

Question 5

What are the products of water photolysis in photosynthesis?

Answer 5

Hydrogen ions, electrons, and oxygen.

Question 6

What is the Calvin cycle?

Answer 6

The light-independent reactions of photosynthesis where carbon dioxide is assimilated to produce sugars.

Question 7

What are the raw materials and products of photosynthesis?

Answer 7

Carbon dioxide and water are the raw materials; carbohydrates and oxygen are the products.

Question 8

What are the three main limiting factors of photosynthesis?

Answer 8

Light intensity, carbon dioxide concentration, and temperature.

Question 9

How does light intensity affect photosynthesis?

Answer 9

Increases the rate up to a point beyond which no further increase occurs due to saturation of photosystems.

Question 10

Why is carbon dioxide concentration a limiting factor?

Answer 10

It is a raw material for carbohydrate production; beyond a certain concentration, the rate of photosynthesis levels off.

Question 11

How did photosynthesis impact Earth’s atmosphere historically?

Answer 11

Increased oxygen concentration, initially oxidizing minerals and later contributing to the atmosphere and oceans.

Question 12

What is chromatography used for in the study of photosynthesis?

Answer 12

To separate and identify different pigments involved in photosynthesis like chlorophyll and carotene.

Question 13

How does paper chromatography work?

Answer 13

Separates substances based on their movement through a stationary phase (paper) using a mobile phase (solvent).

Question 14

What is the range of wavelengths for visible light, and which color has the shortest and longest wavelengths?

Answer 14

Visible light ranges from 400 to 700 nanometers, with violet having the shortest wavelength and red the longest.

Question 15

How is energy utilized in the production of carbohydrates from carbon dioxide during photosynthesis?

Answer 15

Energy absorbed from light is used to convert carbon dioxide and water into carbohydrates, driving the endothermic reactions in the Calvin cycle.

Question 16

How can one design an experiment to investigate the effect of limiting factors on the rate of photosynthesis?

Answer 16

To investigate a limiting factor, keep all variables constant except the one being tested (e.g., light intensity), and measure the rate of photosynthesis via oxygen production or CO2 consumption.

Question 17

Describe how to draw an absorption spectrum for chlorophyll and an action spectrum for photosynthesis.

Answer 17

An absorption spectrum for chlorophyll shows which wavelengths of light are absorbed by chlorophyll, peaking in the blue and red regions. An action spectrum indicates the efficiency of different wavelengths for photosynthesis, similarly peaking in the blue and red areas.