Chapter 1- Cells and Cell Processes

1.1 Cell structure, organisation and cellular resp

Cell surface membrane- Controls movement of materials in and out of cell
Nucleus- Contains genetic material and controls cell activity
Cytoplasm- Where most chemical reactions take place
Ribosomes- Produce proteins (eg. enzymes, insulin and haemoglobin)
Mitochondria- Release energy in aerobic respiration
Cytologists study the structure and function of cells, and a cytotechnologist prepares slides of cells to be examined under a microscope
A tissue is a group of cells with similar structure and function (eg muscle tissue). Organs contain several tissues (eg the heart is made up of muscle tissue). Systems are groups of organs
Respiration is the release of energy from food molecules. The glucose used in respiration is converted usually stored in the cells as fats and glycogen.
All living cells respire, as the body needs energy for building molecule, for growth, movement and warmth
Aerobic respiration is the release of energy from glucose with oxygen present (glucose+oxygen-> carbon dioxide+ water+energy)
During exercise, your body may not be able to provide enough oxygen to muscle cells. Anaerobic respiration (glucose-> lactic acid+ energy)is used to release minimal energy and lactic acid (causes cramp and pain)

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Cell membranes are partially permeable so some materials (like glucose, oxygen and carbon dioxide) can pass through them
Molecules and ions move between cells by diffusion. If there is a high concentration of oxygen outside the cell, it will diffuse into the cell (low concentration) in order to evenly disperse
Water diffuses across the membrane by osmosis; water moves from an area of high concentration to an area of low concentration
Substances which dissolve in water are solutes, and the solute-water balance is regulation of water and dissolves substances in blood plasma
Enzymes are large protein molecules. Cells need enzymes to control chemical reactions, but they can cause health conditions if they are missing
Enzymes are catalysts, they speed up reactions in building up and building down processes.
Human enzymes work best at 37c (body temperature) and at a specific pH, Slight variations will change enzyme activity, but extreme conditions can cause the enzymes to be denatured (the shape changes s0 cannot work)

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