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Calvin cycle (The light-independent reactions )

By: HWC, Views: 7478

The light-independent reactions of photosynthesis occur in the stroma of the chloroplast. Carbon dioxide enters the leaf through tiny pores or stomata and diffuses into the chloroplast. The first stage of the Calvin cycle is the attachment of a carbon dioxide molecule to a 5-carbon ribulose bi...

Gas exchange - driving force

By: HWC, Views: 7790

• The respiratory system is responsible for the movement of gases involved in cellular metabolism. • Oxygen is used up and carbon dioxide is generated during the aerobic breakdown of glucose and other fuel molecules in order to produce ATP. • Three important continuous physiological pro...

Biological organic compounds

By: HWC, Views: 7113

Biological organic compounds contain covalent bonds, mainly C-C and C-H bonds, but also both C and H bonded to such other atoms as O and N. Some of these covalent bonds are nonpolar. Others are polar, either because one atom in the group "hogs" electrons away from other atoms in the group, or...

How Hemoglobin Picks Up and Delivers Oxygen

By: HWC, Views: 7026

All of the cells in our bodies require oxygen (02) for survival and must release carbon dioxide (CO2) as a waste product. The respiratory and circulatory systems work together as delivery systems for these gases. The lungs exchange these gases between the environment and the bloodstream. The bloo...

Protein digestion - stomach & small intestine

By: HWC, Views: 7190

• Protein digestion occurs in the stomach and small intestine. • The stomach enzyme pepsin initiates the process. • Pancreatic and intestinal brush border enzymes complete the digestive process. • In the stomach, pepsin is created from pepsinogen in the presence of pH-lowering hyd...

Major Elements in Biological Molecules: Proteins

By: HWC, Views: 7137

Proteins are chains of amino acids linked by peptide bonds. The 20 different amino acids used to make all proteins differ only in their side chains, and the properties of these side chains account for the great diversity of protein structure and function. Collagen is an example of how a prote...

Energy sources - types

By: HWC, Views: 7905

• The amount of ATP stored in a skeletal muscle cell can only provide muscular activity for two to three seconds. • Muscle cells must be able to generate additional molecules of ATP to continue contracting. • Muscle cells can generate ATP from several processes: • Phosphogen syste...

Mechanisms of capillary exchange

By: HWC, Views: 7875

■ The primary role of capillaries is to permit the exchange of nutrients and wastes between the blood and tissue cells (via interstitial fluid). ■ Oxygen and nutrients move from the blood to the cells. ■ Carbon dioxide and other wastes move from the cells to the blood. The three ba...

Proteins

By: HWC, Views: 6767

Living things must accomplish a great number of tasks just to get through a day, and these tasks are accomplished by a diverse range of biological molecules. In the range of tasks that molecules accomplish, however, proteins reign supreme. Almost every chemical reaction that takes place in living...