the individual‚ (Waugh‚ A. and Grant‚ A.2010). Animal cell consists of a plasma membrane‚ separating the cells internal components from the extra cellular materials and external environment. Inside which are a number of organelles suspended in a watery fluid called cytoplasm. Cytoplasm includes the organelles and the inclusions. Organelles are highly specialized structures and often enclosed in their own membrane within the cytoplasm‚ specialised for specific activities. They include nucleus
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Describe the pathways AND mechanisms by which water passes from the soil to the xylem vessels in the root. (7 marks) As there is a higher water potential in the soil‚ and there is a lower water potential in the root hair cells‚ the water molecules move from the area of high potential to the area of low potential. From the soil into the roots. The process by which the molecules of water move into the root hair cells is ’osmosis’. This is a passive process‚ meaning that no energy (in the form of
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Cell Membrane Simple diffusion is when a small‚ non-polar molecule passes through a lipid bilayer. It is classified as a means of passive transport. In simple diffusion‚ a hydrophobic molecule can move into the hydrophobic region of the membrane without getting rejected. Simple diffusion does not involve a protein. An example of simple diffusion is osmosis. Hydrophilic molecules cannot participate in simple diffusion because they would move into the hydrophobic region of the membrane and be
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molecules can diffuse across cell membranes while some substances must be transported across the membrane by proteins. The membrane is in control of what enters and leaves the cell. However‚ certain conditions may damage the cell membrane’s structure. Beet cells‚ which are plant cells‚ have a water-soluble pigment called betacyanin‚ which is stored in its vacuole. The tonoplast‚ or the vacuole’s membrane‚ acts with the cell membrane of the cell to prevent the
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resting membrane potential when extracellular K+ concentration is increased? -The resting membrane potential will become more positive when K+ concentration is increased. 2. Explain why the resting membrane potential had the same value in the cell body and in the axon. -The resting membrane potential has the same value in the cell body and the axon because the typical resting membrane potential is the same throughout the entire neuron. 3. Describe what would happen to the resting membrane potential
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Mammalian cells are eukaryotic this means that all of their cells have common components‚ membrane bound organelles which prokaryotic cells do not this is shown in figure 1. Organelles are purpose made to carry out a specific function that is necessary within a cell. Due to the specificity of both conditions and concentrations with in these organelles these are compartmentalized. Encasing the organelle in a membrane allows is to do this. In most cases a single phospholipid bilayer is used however in certain
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neurons to form complex interconnected circuits‚ allowing the nervous system to moderate other systems within the body. When an action potential of a pre-synaptic neuron reaches the axon terminal‚ voltage-gated calcium channels are open. This allows calcium ions to enter the terminal. The calcium instigates vesicles containing neurotransmitters to bind with the cell membrane‚ releasing their contents into a space between the cells‚ called a synaptic cleft. After the neurotransmitters diffuse across the
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the plasma membrane‚ and to indicate the driving force for each. 3. To determine which way substances will move passively through a dif- ferentially permeable membrane (given the appropriate information on concentration differences). 01_001_016_PhyEx8_AP_Ch01 1/10/08 5:27 PM Page 1 The diffusion of solute particles dissolved in water through a differentially permeable membrane is called simple diffu- sion. The diffusion of water through a differentially perme- able membrane is called
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Name and describe the three main parts of a cell. plasma membrane-forms a cell’s flexible outer surface‚ separating the cell’s internal environment (inside the cell) from its external environment (outside the cell) cytoplasm- consists of all the cellular contents between the plasma membrane and the nucleus. nucleus- is the largest organelle of a cell. The nucleus acts as the control center for a cell because it contains the genes‚ which control cellular structure and most cellular activities
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The body maintains homeostasis by the feedback inhibition‚ in which a stimulus produces a response that opposes the original stimulus. 3. The axon terminal is the nerve ending. The nodes speed up the message. The myelin sheath is an insulating membrane. The axon carries impulses away from the cell body. The cell body is the largest part of a typical neuron. The dendrites carry impulses from the environment or from other neurons toward the cell body. The nucleus is the control center of the cell
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