Plants make their own food by photosynthesis. Carbon dioxide and water react together in the presence of light and chlorophyll to make glucose and oxygen. The glucose is converted into starch, fats and oils for storage. It is used to make cellulose for cell walls, and proteins for growth and repair. It is also used by the plant to release energy by respiration.
is a chemical reaction that happens in the chloroplasts of plant cells. It produces glucose for use by the plant, and oxygen as a waste product. Here are the equations for photosynthesis:
The product of photosynthesis is a , such as the sugar , and oxygen which is released into the atmosphere (Figure 9l-1). All of the sugar produced in the photosynthetic cells of plants and other organisms is derived from the initial chemical combining of carbon dioxide and water with sunlight (Figure 9l-1). This chemical reaction is catalyzed by acting together with other , , , , and molecules. Sugars created in photosynthesis can be later converted by the plant to starch for storage, or it can be combined with other sugar molecules to form specialized carbohydrates, such as . Sugars can also be combined with other such as nitrogen, phosphorus, and sulfur, to build complex molecules such as proteins and nucleic acids.
The of a is the amount of biomass produced through photosynthesis per unit area and time by plants, the primary producers. Primary productivity is usually expressed in units of energy (e.g., joules m day ) or in units of dry organic matter (e.g., kg m year ). Globally, primary production amounts to 243 billion metric tons of dry plant biomass per year. The total energy by plants in a community through photosynthesis is referred to as (). Because all the energy fixed by the plant is converted into sugar, it is theoretically possible to determine a plant's energy uptake by measuring the amount of sugar produced. A proportion of the energy of gross primary productivity is used by plants in a process called . Respiration provides a plant with the energy needed for various plant physiological and morphological activities. The general equation for respiration is:
Photosynthesis is the first stage of energy flow through an ecosystem. You and all other animals on earth rely on the energy that plants store for life. But animals aren’t the only organisms that burn energy. Plants burn energy as they grow, too. In both plants and animals, the process of — which releases stored energy for use — occurs in the mitochondria inside each cell.
- Glycolysis and Krebs cycle
- Takes place in chlorophyll - containing plant cells during photosynthesis
Roles of ATP
ATP is an immediate energy source due to the instability of the phosphate bonds
ATP is the source of energy for:
- ATP provides the energy for muscle contraction, it provides the energy for the filaments of the muscle to slide past one another and shorten the overall length of the muscle fibre
- ATP molecules fix to myosin heads which cause them to detach from the actin filament at the end of one 'row' movement
ATP provides the energy needed to build up macromolecules from their basic units:
- Polysaccharide synthesis from monosaccharides
- Polypeptide synthesis from amino acids
- DNA/RNA synthesis from nucleotides
- ATP Provides the erngy to change the shape of carrier proteins in plasma membranes.
Close to lower epidermis allowing rapid diffusion of gases into and out of leaf.
In the stroma, the light-independent (Calvin cycle) photosynthetic reactions take place- the bonding of carbon dioxide with hydrogen (from water), and their rearrangement to form glucose, CHO
Chloroplasts are also found in the outer layer of cells (cortex) in the stems of non-woody plants.