Module 7: Photosynthesis

Thylakoids

A flattened membrane sac inside the chloroplast, used to convert light energy to chemical energy (site of light-dependent reactions).

Chlorophyll

A green pigment located within the chloroplasts of plants, algae, and certain prokaryotes. Chlorophyll a can participate directly in the light reactions, which converts solar energy to chemical energy.

Chloroplast

An organelle in prokaryote cells that absorbs sunlight and uses it to drive the synthesis of organic molecules (sugars) from carbon dioxide and water.

Carbon fixation:

Inorganic carbon (particularly in the form of carbon dioxide) is converted to organic compounds by living organisms. The organic compounds are then used to store energy and as building blocks for other important biomolecules.

What is the relevance of photosynthesis to other living things?

It is the number one source of oxygen in the atmosphere and without photosynthesis, the carbon cycle could not occur, killing all life that requires oxygen.

What is the process of photosynthesis?

Photosynthesis is a multi-step process that requires sunlight, carbon dioxide, and water as substrates. It produces oxygen and glyceraldehyde-3-phosphate (G3P or GA3P), simple carbohydrate molecules that are high in energy and can subsequently be converted into glucose, sucrose, or other sugar molecules.

How does photosynthesis work in the energy cycle of all living organisms?

Photosynthesis takes the energy of sunlight and combines water and carbon dioxide to produce sugar and oxygen as a waste product. The reactions of respiration take sugar and consume oxygen to break it down into carbon dioxide and water, releasing energy.

Describe short and long wavelengths of light?

Shorter wave lengths have higher energy and the longer ones have less energy.

Identify the substrates and products of photosynthesis?

Substrates are CO2 and H20 and the products are O2 and sugar.

How and where photosynthesis takes place within a plant?

Takes place in chloroplasts (containing the chlorophyll).

Calvin cycle:

The Calvin cycle is a process that plants and algae use to turn carbon dioxide from the air into sugar, the food autotrophs need to grow. Every living thing on Earth depends on the Calvin cycle. Plants depend on the Calvin cycle for energy and food.

What are the main structures involved in photosynthesis?

The main cellular structures that allow photosynthesis to take place include chloroplasts, thylakoids, and chlorophyll.

How do plants absorb energy from sunlight?

They trap the light in the leaves and use the sunlight as energy for making food through photosynthesis.