abida Archive

CELL DIVISION

THE CELL CYCLE The period from the time a cell is produced until it completes mitosis is called cell cycle. Cell division occurs during growth and repair processes. Cell cycle has following basic stages: (a)  Mitosis: It is the division of the nucleus. (b) 

OBJECTIVES Of Harvest Energy Stored In Nutrients

Multiple Choice Questions MCQs: Four options are given at the end of each statement. You should encircle.one option from them. The first step of respiration is: (a) ETC            (b) Krebs cycle          (c) Glycolysis              (d) Fermentation The end product of glycolysis is: (a) Citric acid

MODEL SUBJECTIVE QUESTION

Describe the process of glycolysis. Discuss evolutionary perspective of glycolysis. Write note on fermentation. Discuss different steps of Krebs cycle. Draw Krebs cycle. Describe different steps of electron transport chain. Give number of molecules of ATP produced during respiration of one molecules of glucose.

DEFINITIONS AND KEY POINTS

  TERMS DEFINITIONS Electron transport chain • The     collection    of   molecules     embedded     in   the     inner membrane     of    the     mitochondrion      is    called      electron transport chain Krebs cycle Krebs cycle is a series of reactions in which the pyruvate from glycolysis is oxidized to CO2. Thermodynamics

THE METABOLIC POOL

Th destructive chemical reactions (catabolism) of glycolysis and the Krebs cycle pe orm many functions. They constitute a metabolic pool. This pool supplies materials for synthesis (anabolism) of many important cellular components. Therefore, the balance between catabolism and anabolism is maintained. It maintains homeostasis

CONTROL OF METABOLISM

Cells are very efficient. They do not waste. energy and do not make substance which they do not need. Following process keeps the metabolism of different compounds under control: Control of anabolism Sometimes, an amino acid is present in larger amount. The anabolic pathway

METABOLISM OF FATS AND PROTEINS

ALTERNATIVE FOOD MOLECULES The catabolism of glucose is the most common metabolic pathway in cells. But animals also consume fats and proteins. These may be used to harvest energy. Fats Fats are built from long chain fatty acids and glycerol. They form triglycerides. The

AEROBIC RESPIRATION: THE MAJOR SOURCE OF ATP

The glycolysis and fermentation are inefficient processes. Thus the end product of glycolysis (pyruvate) still contains large amount of energy. This energy can be released by further oxidation. Free oxygen accumulated in the atmosphere of the earth as a result of photosynthesis. Therefore, evolution

GLYCOLySIS

Glycolysis is the initial step of catabolic chemical reactions. It occurs almost in all the cells. Six-carbon glucose molecule is broken down into two molecules pyruvate during glycolysis. Pyruvate is a .three carbon compound. There is net production of two molecules of ATP during