Jan 4, engineering science n3 exam papers and answers.
Hormone binding sites receptor proteins Proteins embedded in the membrane, which bind to specific hormones. When the hormone binds, it causes the receptor protein to undergo a conformational change, which signals the cell to perform a function. For example, insulin receptors.
Immobilized Enzymes Integral proteins that catalyze specific chemical reactions. Many of these enzymes catalyze metabolic reactions or are a part of a metabolic pathway, such as ATP Synthase in aerobic respiration.
Cell Adhesion Proteins that form tight bonds between adjacent cells in tissues and organs. For example, gap junctions. Receptors for neurotransmitters at synapses between two nerve cells.
Glycoproteins on the surface can also be used for cell identification purposes. Channels for passive transport Integral proteins that span the membrane and provide a passageway for molecules to move from an area of high concentration to low concentration.
Specific proteins are also used for facilitated diffusion. Pumps for Active Transport Proteins that use ATP to move substances from a low concentration to a high concentration across the membrane. Most of the cell membrane contains phospholipids and proteins Cholesterol is a lipid that belongs in the steroid group and is also a component of the cell membrane Most of the cholesterol molecule is hydrophobic and therefore embeds within the tails of the bilayer.
A small portion hydroxyl —OH group is hydrophilic and is attracted to the phospholipid head Applications and skills: Cholesterol in mammalian membranes reduces membrane fluidity and permeability to some solutes.
Cholesterol embedded in the membrane will reduce the fluidity making the membrane more stable by the hydrophilic interactions with the phospholipid heads While cholesterol adds firmness and integrity to the plasma membrane and prevents it from becoming overly fluid, it also helps maintain its fluidity by disrupting the regular packing of the hydrocarbon tails.
At the high concentrations it is found in our cell's plasma membranes close to 50 percent, molecule for molecule cholesterol helps separate the phospholipids so that the fatty acid chains can't come together and crystallize. Drawing of the fluid mosaic model.
The diagram of the plasma membrane above shows the phospholipid bilayer, cholesterol, glycoproteins, and integral transmembrane and peripheral proteins. Integral proteins are embedded in the phospholipid of the membrane, whereas peripheral proteins are attached to its surface.
Glycoproteins are carbohydrates attached to surface proteins. I will redraw and change. Analysis of evidence from electron microscopy that led to the proposal of the Davson-Danielli model. Analysis of the falsification of the Davson-Danielli model that led to the Singer-Nicolson model.
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Passive transport means there is no expenditure of energy ATP. Passive transport requires the substance to move from an area of high concentration to low concentration. Simple diffusion across membranes occurs when substances other than water move across the phospholipid bilayer between the phospholipids or through protein channels.
Substances that move across the membrane are usually small non-charged particles i. Oxygen, Carbon Dioxide, and Nitrogen or other lipids. Each protein channel structure allows only one specific molecule to pass through the channel.Apr 05, · Notes for IB Biology Chapter (Meiosis).
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The UPSC civil services prelims exam is the first . UPSC Civil Service Prelims General Studies Paper 1 Sub Topic Split Though the History and Culture together had 20 questions, there split was between them.
And out of the 8 questions in History, 6 questions were from modern India and 1 each from ancient and medieval India. Topic: Proteins. No.
Since the revamp of the Biology syllabus, we as biology students have been short of notes ever since. In fact its so pathetic that we have to focus on the molecular level of biology, and not on the overall systems unlike our physics counterparts.
In the CNY of , a group of bio Students from the various schools set. GCSE Biology revision covering Cell Activity, Genetics and DNA, Green Plants as Organisms, Humans as Organisms, Living Things in their Environment, Polymerisation of Amino Acids, The .
Exam and Revision Information Page 1 Index: Art and Design 2 Biology 3 Business Management 4 Chemistry 5 Drama 6 English 7 Notes on Cezanne and Peploe are available from the department. The exams at all levels will be exactly as the pupils experience in their prelim.