bacteria’s contents intact. The Cell Membrane: Is a phospholipid bilayer that completely surrounds a bacterial cell. Cell membrane acts as a highly selective barrier. This barrier prevents materials from diffusing into and out of the cell. This allows the cell to take up chemicals and nutrients needed for survival while keeping the cell components separated from the environment. The fluid and all its dissolved or suspended particles that can be found within a bacterial cell are called the Cytoplasm.
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Give an account of protein structure and function Protein structure 1 Proteins consist of amino acids joined together (in chains) 2 A protein is unique because of the sequence of amino acids 3 The amino acids are joined by strong peptide bonds 4 to produce the primary structure 5 Further (weak) hydrogen bonding between acids 6 produce the secondary and tertiary structures A maximum of 4 marks can be gained from this section. Protein function 7 Some proteins are enzymes + named example
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CHAPTER 1 Cell Structure and Organisation Cells * All living organisms are made up of cells * The simplest living organisms have one cell only * His name is unicellular-e.g. bacteria. * Most other living organisms have many cells- his name is multicellular- e.g. Man‚ plants‚ animals. * Cells can be seen only under microscope Cell structure All cells have the following structure in common: a) Cell membrane- a very thin layer of protein and fat‚ surrounding the cell. It is
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Testing Cell Transportation Across a Membrane Introduction Cells have the amazing ability to transport certain molecules in or out of their membrane. Some require no energy to do so (passive transport) while others require energy to be processed through (active transport). There is also the transportation of water across a membrane‚ which has its own term of osmosis. Too much of something can be taken in‚ or too little enters. This especially happens to plants‚ who require water (and sun) to live
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control as exchange Main function of stomata : Allow enough C02 to enter the leaf to optimize photosynthesis‚ while conserving as much water as possible Structure of stomata * Each stomata consists of a stoma (minute pore) which are surrounded by 2 guard cells. * Stomata closes and opens according to the turgidity of the guard cells * Stomata also allows for cooling of the leaf by loss of water through transpiration to lower leaf temperature * Guard cells open and close to control
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The nucleolus (plural nucleoli) is a non-membrane bound structure. Composed of proteins and nucleic acids found within the nucleus. Ribosomal RNA (rRNA) is transcribed and assembled within the nucleolus. Three major components of the nucleolus are recognized: the fibrillar centers (FC)‚ the dense fibrillar components (DFC)‚ and granular components (GC). The DFC consists of newly transcribed rRNA bound to ribosomal proteins‚ while the GC‚ contains rRNA bound to ribosomal proteins that are beginning
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THE EFFECT OF CHEMICALS AND TEMPERATURE ON MEMBRANE DESTRUCTION AND PERMEABILITY IN BEETROOT (Beta vulgaris) Introduction The cell membrane is made up primarily of phospholipids and proteins which contribute to its selectively permeable nature. The function and permeability of the cell membrane depends on its intact structure. When destroyed‚ the permeability of the cell membrane is disrupted causing cellular contents to leak out. The cell membrane can be destroyed by physical damage‚ chemicals
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millimetres for the measurements given in each row. The first row has been completed for you. Ensure that your answers use the correct unit symbols. Nanometre Micrometre Millimetre 5 0.005 0.000005 1 1 1 3 7 0.5 3) When studying cells structure using a microscope the smallest unit of measurement commonly used to describe findings is the nanometre. Explain why. Magnification and Resolution 1) Define the following terms: Magnification: Resolution: 2) Visible light has a wavelength
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1.1 Studying the Structure of Cells In 1665‚ English scientist Robert Hooke became the first person to study cells Cell Structure Nucleolus: Makes Ribosomes‚ which help to make proteins Nuclear Membrane: Protects the contents of the nucleus Nuclear Pores: Allow materials‚ such as ribosomes‚ in and out of the nucleus |Light Microscope |Electron Microscope | |Uses light source |Beams of electrons
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p53: Structure‚ Function and Therapeutic Applications Ling Bai and Wei-Guo Zhu1 Department of Biochemistry and Molecular Biology‚ Peking University Health Science Center‚ Beijing‚ China [L. Bai‚ W.-G. Zhu]; Department of Biotechnology‚ Guilin Medical College‚ Guilin‚ China [L. Bai] Since the p53 tumor suppressor gene has been found to be mutated in more than 50% of human cancers‚ it has attracted the interest of numerous researchers. The capacity of p53 for multiple biological functions can be
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