Chapter 4 – Cellular Metabolism Cellular metabolism enables the organism to grow.
You are responsible for the following figures and tables : Fig. 4.14 - metabolic processes, anabolic and catabolic. Fig. 4.1, 4.2, 4.3 – Macromolecules. Fig. 4.4 - control of metabolism is achieved by enzymes. -see table summary in the attached lecture handout - Fig. 4.5 - metabolism occurs complex biochemical pathways. Fig. 4.15 - Metabolic reactions can be regulated by feedback mechanism. Read TB, p.108, on 'cellular respiration'. Fig. 4.6 - Cellular respiration consists of 3 biochemical pathways. -see table summaries in the attached lecture handout - -see also Ch.9 regarding ‘oxygen debt’ resulting in the synthesis of lactate instead of pyruvate- Fig. 4.17, 4.18 - RNA and DNA. Fig. 4.24 – DNA. Fig. 4.22 - transcription – translation Fig. 4.25 - Mutation Fig. 4.26 - Explain PKU.
Rate-limiting enzymes are the first enzyme in a series of enzymes that are all part of a metabolic pathway.
Control of a rate-limiting enzyme prevents accumulation of intermediates.
Products of metabolic reactions can inhibit the rate-limiting enzyme through negative feedback (Fig. 4.15) .
Metabolism is made possible through the action of Enzymes
Enzymes are globular proteins that promote chemical reactions by lowering the activation energy required to start the reaction and enhancing the reaction rate.
They are catalysts that do not get chemically changed in the reaction themselves .
Since they are not consumed by the reaction , they are needed only in very small quantities.
Enzymes are specific and act only on particular substrates. There are enzymes that make bonds and synthesize molecules and there are those enzymes that break bonds and degrade molecules into smaller molecules.
The third phosphate is attached with a high energy bond.
This chemical energy can be easily transferred to other molecules in metabolic processes.
CELLULAR RESPIRATION = Need for O 2 and Release of CO 2 as waste from tissues GLYCOLYSIS CONVERSION STEP CITRIC ACID CYCLE ETC LOCATION cytoplasm mitochondria Mitochondrial matrix mitochondrial inner membrane O 2 Required? NO yes yes yes Starting Product glucose (6-C) 2 pyruvates (2 x 3C) Acetyl CoA (2 x 2C) 10 NADH 2 FADH 2 End- Products 2 pyruvates (2 x 3-C) 2 -4 ATP 2 NADH 2 Acetyl CoA 2 NADH 2 CO 2 6 NADH 2 FADH 2 2-4 ATP 4 CO 2 30 ATP 2-4 ATP 2-4 ATP TOTAL 34-38 ATP