Biology Exam Revision Cell Membrane - 1480 Words

Biology Exam Revision Cells Cell Membrane The cell membrane surrounds the cytoplasm of a cell, separating its contents from the environment around it. The cell surface membrane consists of two layers of phospholipids and regulates what can enter and leave the cell. It is a semi-permeable membrane embedded with proteins, including receptors on the outer surface. Nucleus The nucleus is the ‘brain’ of the cell. It is a large, round organelle and is surrounded by the nuclear envelope (a double membrane). The nuclear envelope allows the exchange of materials between the nucleus and cytoplasm through its large, nuclear pores. The nucleus contains DNA therefore the information to regulate the metabolism and reproduction for the cell. It also contains a dark staining area called the nucleolus. The nucleolus produces ribosomes. Mitochondrion The mitochondrion has a double membrane surrounding its ellipse shape. Some of the reactions of aerobic respiration (the process living things go through to use food energy) occur in the mitochondrion and they are the ‘powerhouses’ of the cell. They produce energy in the form of ATP. Ribosomes Ribosomes are the site of protein synthesis and are made up of two subunits. One of these units is large, and the other is small. These subunits consist of protein and ribosomal RNA. Ribosomes can be found floating free in a cell, or attached to the endoplasmic reticulum. Rough Endoplasmic Reticulum The rough endoplasmic reticulum is covered withShow MoreRelatedAn Investigation Into The Rate Of Osmosis1756 Words   |  8 PagesAbstract Water diffuses across cellular membranes by the process of osmosis. This occurs in all animal, plant and protozoa cells. Furthermore, this report examines ‘an investigation into the rate of osmosis through a semi-permeable membrane’ and further assesses whether this rate is affected by sucrose concentration. Dialysis bags containing variable sucrose concentrations were placed in a solution containing either tap water or 60% sucrose. These bags were then weighed at fifteen minute intervalsRead MoreSkeletal Muscle, Cardiac Muscle And Smooth Muscle2791 Words   |  12 Pages Contents Page Introduction 4 In Brief: Skeletal Muscle, Cardiac Muscle Smooth Muscle Image 1.0 Anatomy Of Smooth Muscle Table – Basic Muscle Comparison 5 Note: See Appendix For Further Detail. Image 1.1 Muscle Cell Variations Image 2 Stimulus Transmission Image 3 Axon Junction 6 Events At The Neuromuscular Junction And Of A Synaptic Transmission Skeletal Muscle In More Detail Including: Fascia Epimysium, Perimysium, Endomysium, Aponeurons 7 PeriosteumRead MoreAp Psychology Review Packet12425 Words   |  50 Pagesprocess by which the eyes lens changes shape to focus near or far images on the retina. 3.Acetylcholine:  neurotransmitter that enables muscle action, learning and memory. 4.Achievement Motivation:  desire for accomplishment. 5.Achievement Test:  an exam designed to test what a person has earned. 6.Acoustic Encoding:  encoding of sound, especially words. 7.Acquisition:  the initial stage when one links a neutral stimulus and an unconditioned stimulus. 8.Action Potential:  a neural impulse; a brief electricalRead MoreStephen P. Robbins Timothy A. Judge (2011) Organizational Behaviour 15th Edition New Jersey: Prentice Hall393164 Words   |  1573 Pagesfeatures—clear writing style, cutting-edge content, and engaging pedagogy—the fourteenth edition has been updated to reflect the most recent research within the field of organizational behavior. This is one of the most comprehensive and thorough revisions of Organizational Behavior we’ve undertaken, and while we’ve preserved the core material, we’re confident that this edition reflects the most important research and topical issues facing organizations, managers, and employees. Key Changes to the