Cells at Work- Cell Metabolism (Chapter 6) Flashcards
1) Explain what is meant by the terms ‘metabolism’, ‘catabolism,’ and ‘anabolism.’
- Metabolism: all the chemical reactions that take place in cells, and therefore in the organism of which the cells are part.
- Catabolism: reactions in which large molecules are broken down to small ones.
- Anabolism: reactions in which small molecules are built up into larger ones.
2a) Why are enzymes necessary in living organisms?
Enzymes are proteins that allow chemical reactions to take place at normal body temperature. Without enzymes these reactions would be too slow to be of any use to the body.
2b) What is meant by the statement that enzymes are specific?
Each enzyme will combine with only one particular substrate and is therefore involved in only one specific reaction.
2c) List the factors that affect enzyme activity.
Temperature, concentration, pH,
3) What is the difference between breathing and cellular respiration?
The process of cellular respiration and breathing are part of the same process. When you inhale, carbon dioxide is replaced by oxygen in your blood, this oxygen is required by cells to perform aerobic cellular respiration as opposed to anaerobic cellular respiration- a similar process that does not require oxygen.
4a) Write a chemical equation that summarizes cellular respiration.
C6H12O6 + 6O2 –> 6CO2 + 6H2O + 36
or 38 ATP molecules
4b) Is the summary an accurate picture of what happens in cellular respiration? Explain.
It is an accurate representation as glucose + oxygen gives carbon dioxide + water + 36 or 38 ATP molecules.
4c) Why is it necessary for cells to respire?
Cellular respiration provides the cells with energy which helps the cells complete its vital functions. Without the cellular respiration, the cells die.
5a) Explain the role of ATP and ADP in cellular respiration.
Removal of the third phosphate group releases the energy in the band. ATP can thus be used to transfer the energy released in cellular respiration to processes in the cell that require energy. The ADP formed when the energy is released can be reused to store some more energy from the cellular respiration. Thus ATP acts as a go-between- a way of transferring energy from cellular respiration to cell processes that utilize energy.
5b) What parts do ATP and ADP play in the synthesis of organic materials?
Synthesis requires both matter and energy- matter in the form of small molecules to be joined, and energy to form the chemical bands that hold the smaller units together ( like anabolism).
6) What is the difference between aerobic and anaerobic respiration in terms of: the quantity of energy released, the reactions involved and the location of the chemical reactions within the cell.
Aerobic respiration uses oxygen to produce energy in the form of ATP, with water and carbon dioxide as by-products. If oxygen is absent, the cells still produce energy, this time using anaerobic respiration. During aerobic respiration, oxygen (O2) reacts with sugar or glucose (C6H12O6), producing carbon dioxide (CO2), water (H2O), and energy (ATP). During anaerobic respiration, when there is not enough oxygen, cells break down glucose into lactic acid (C3H6O3) and energy (ATP). Although both processes produce energy, more ATP molecules are generated from aerobic than anaerobic respiration.
7) Explain what is meant by ‘oxygen debt’ or ‘recovery oxygen.’ How is an ‘oxygen debt’ paid?
Lactic acid from anaerobic respiration is taken by the blood to the liver, where i can be recombined with oxygen to form glucose and eventually glycogen. As this process requires oxygen, physiologists say that, when cells are respiring anaerobically, the body is incurring an ‘oxygen debt.’ After vigorous exercise one continues to breathe heavily for some time because the oxygen debt must be repaid by converting lactic acid to glucose. The extra oxygen requires after exercise may also be called recovery oxygen.
8) List the processes for which cells need energy. Indicate whether each process is common to all cells or whether the process would occur only in particular cells.
Cells need energy to maintain our body temperature and to to form a compound called adenosine triphosphate, or ATP.
9) What is synthesis? Why do reactions involving synthesis require matter and energy?
Synthesis is the combining of small molecules to make larger molecules (it means the same as anabolism). Synthesis requires both matter and energy- matter in the form of small molecules to be joined , and energy to form the chemical bonds that hold the smaller units together.
