chapter 2.5 cell metabolism Flashcards
Cell metabolism is critical to the survival of cells. Biochemical processes in the cell are influenced by: the nature and arrangement of internal membranes Explain how the structure of internal membranes of mitochondria and chloroplasts facilitate some biochemical processes. the presence of specific enzymes Explain that in a metabolic pathway: there are many regulated steps, each step loses some energy as heat, some steps produce intermediate compounds, specific enzymes are required at each s
What is cell metabolism?
Metabolism refers to all the biochemical reactions occuring in an organism and is critical to the survival of cells and thus the organism as a whole
What are metabolic pathways?
Most biochemical reactions occur in what is termed metabolic pathways. Where the substrate for the first reaction is converted to a product by the first enzyme. This product is the substrate for the second reaction and so forth. This sequence of chemical conversions of substrates into products continues untill the end-product is made.
Why is each step catalysed by a specifc enzyme?
As each new substrate has its own unique shape and can only bind to the active site of its own enzyme.
What are the cell advantages of the many regulated steps in metabolic pathway?
Advantages:
- The cell can exert a greater level of control of the reactions with a different enzyme at each step.
- Other substrates can ‘feed in’ at different points in the pathway, allowing cells to utilise other resources.
- Some steps produce intermediate products that are often essential molecules needed by cells.
- The cell can release energy more gradually, a portion of which can be trapped in energy coupling processes, such as ATP synthesis.
Is chemical energy turned into heat during each step of a metabolic pathway?
During each step of a metabolic pathway chemical energy is turned into heat, which can be used to maintain body temperature in many organisms, including humans.
What are the two types of metabolic pathways?
- Some metabolic pathways release energy by breaking down complex molecules to simpler ones e.g. aerobic respiration (occuring in the mitochondria[occurs on the inner folded membrane allowing a larger surface area, increasing productivity having key enzymes]), breaking down glucose (complex molecule) into carbon dioxide and water (simpler molecules).
- Some metabolic pathways change simple molecules to build complex ones e.g. photosynthesis (occuring in the chloroplast on flattened sac-like membranes that contain chlorophyll and enzymes), using simple molecules carbon dioxide to build complex molecules such as glucose and oxygen.
What enviormental factors impact metabolic pathways?
Temperature: At high temps enzymes can denature (thus can’t bind) and at low temps enzymes function slower.
pH: At to high pH enzymes can denature, and at low pH enzyme activity decreases.
Co-factors: Inorganic substances can bind on the active site, elsehwere on the enzyme or with the substrate and can include: copper, ion and zinc.
Inhibitors: Competitive inhibitors (binding to active site instead of substrate) Non-competitive inhibitors (bind to the enzyme, changing its shape and not allowing the substrate to fit).
What chemicals interfere with cell metabolism?
Poisions (preventing inhibiting e.g. cyanide and malonate)
Herbicides (can act as competitive inhibitors)
Medicines (e.g. antibiotics help kill bacteria however can stop specific enzymes having negative impacts on the body.
Insecticides
