Textbook Questions Page 216: 1, 3, 5, 6, 8, 9

Answers 1. Normal metabolism helps make homeostasis possible. Through all its functions the body strives for a state of healthy, relatively constant, internal environment 3. Humans get energy from the sun. The sun is the origin of all energy. Plants capture energy (through photosynthesis) and we either eat the plants or eat animals that eat the plants. We then gain the nutrients that provide energy for metabolism.

Answers 5. Catabolism is the breaking down of complex molecules into simpler ones during chemical reactions. Nutrients are made available by digestion are broken down so they can enter cells. Catabolism releases energy. Anabolism is the combining of molecules during chemical processes in order to build materials of living tissue. Anabolism requires energy

Answers 6. As nutrients break down in cells, they produce more energy than can be immediately used (metabolic reactions only require a small amount) so some energy needs to be stored. Molecules such as adenosine triphosphate (ATP) serve as energy warehouses. Energy is carried in the bonds between phosphate groups in ATP. When a cell needs energy the bond between the 2nd and 3rd phosphate group is broken.

Answers 8. Osmosis controls the movement of fluids (water). The body balances the concentration of substances dissolved in it. This is done with the help of ions of four minerals: sodium and chlorine (in the blood) and potassium and phosphate (in the cell cytoplasm)

Answers 9. There are a few reasons why an alligator’s metabolic rate is different from a persons: Body temperature: an alligator is cold blooded. A cold blooded animal’s metabolic rate depends on the sun (so it’s metabolic rate would vary throughout the day and from day to day). Body size Energy supply