4.1

• The revision notes for CIE AS Biology also cover topics such as the structure of DNA, the cell cycle, and the process of protein synthesis.
• The revision notes for CIE AS Biology cover topics such as the structure of DNA, the cell cycle, and the process of protein synthesis.
• The circulatory system consists of the main blood vessels, blood vessels: structures & functions, cells of the blood, the role of water in circulation, blood, tissue fluid & lymph.
• Infectious diseases are transmitted and controlled through prevention & control measures.
• Antibodies are used in vaccination and have various uses.
• Vaccines work by using the principles of immunity to control diseases.
• Transport of oxygen & carbon dioxide involves red blood cells, haemoglobin & oxygen, the chloride shift, plasma & carbon dioxide, the oxygen dissociation curve, the bohr shift.
• Gas exchange occurs in the gas exchange system, which includes the human gas exchange system, and involves the distribution of tissues.
• Immunity involves phagocytes, antigens, primary immune response, memory cells & immunity.
• The heart has a structure, the walls of the heart, and undergoes a cardiac cycle.
• The Mitotic Cell Cycle includes replication & division of nuclei & cells, chromosome structure, mitosis, the cell cycle, the role of telomeres, and the role of stem cells.
• Cell membranes & transport include fluid mosaic membranes, the fluid mosaic model, components of cell surface membranes, cell signaling, and more.
• Eukaryotic cell structures & functions include animal & plant cells, the vital role of ATP, and the differences between prokaryotic and eukaryotic cells.
• Enzymes have a specific mode of action and can be measured using colorimetry.
• Biological molecules include carbohydrates & lipids, proteins, water, and enzymes.
• Transport in plants includes structure of transport tissues, plant transverse sections, xylem & phloem distribution, xylem vessels, elements, phloem sieve tube elements, water & mineral ion transport in plants, transpiration in plants, water & the transpiration pull, xerophytic plant leaf adaptations, movement in the phloem, and the sucrose loading mechanism.
• The Microscope in Cell Studies includes magnification calculations, eyepiece graticules & stage micrometers, resolution & magnification, calculating actual size, and more.
• Cells are the basic units of living organisms, and understanding their structure and function is crucial to understanding life.
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• The cell surface membrane creates an enclosed space separating the internal cell environment from the external environment.
• Membranes are selectively permeable.
• Membranes are vital structures found in all cells.
• Membranes in Membrane-Bound Organelles.
• A phospholipid bilayer is composed of two layers of phospholipids; their hydrophobic tails facing inwards and hydrophilic heads facing outwards.
• The lipid tail is non-polar (hydrophobic) and insoluble in water.
• Phospholipids structurally contain two distinct regions: a polar head and two nonpolar tails.
• The fluid mosaic model describes cell membranes as 'mosaics' because the scattered pattern produced by the proteins within the phosph