Experiment 2 : Transport Across Membrane Name : Matrix No : Group : B Semester : 1 Date of Experiment : 05.09.2013 Lecturer’s Name : Miss OBJECTIVE To study the effects of hypotonic‚ hypertonic and isotonic solutions on plant and animal cells. INTRODUCTION In cellular biology the term membrane transport refers to the collection of mechanisms that regulate the passage of solutes such as ions and small molecules through biological membranes‚ which are lipid bilayers that
Premium Cell wall Cell Cell membrane
13 THE MEMBRANES OF DIFFERENT TYPES OF CELLS ARE INVOLVED IN MANY DIFFERENT FUNCTIONS – 25 MARKS Membranes are found in all organisms‚ around and within cells. They control the movements in and out of cells‚ as well as protecting cells. They also allow different functions to occur. They have the same basic structure called the plasma membrane. All plasma membranes‚ around or inside cells have a same phospholipid bilayer structure. Phospholipids contribute to the flexibility of membranes and transfer
Premium Cell membrane Protein Cell
RESTING POTENTIAL Resting potential is the membrane potential when a neuron is not conducting any electrical impulse or signal. The resting potential is around -75 mV. During resting potential‚ the inside of the axon is negative GRADED POTENTIAL ACTION POTENTIAL Action potential is a fleeting reversal of the membrane potential‚ caused by changes in permeability of the plasma membrane of neuron to potassium and sodium ions causing an electrical impulse to be transmitted along the axon.
Premium Action potential Electric charge Neuron
Cell membranes are composed of a lipid bilayer. It has different receptors that allow different ions to pass‚ depending on the conditions in the cell. Leak channels- always open allow ions to flow back and fourth across the cell membrane Na cl ‚K and Ca ions and they just flow back and fourth without any gate keeper or obstruction‚ When the neuron is at rest its cytoplasm is Negatively charged. That means that it is not going under depolarization‚ we use the term resting potential. Modality
Premium Action potential Neuron
Action potential to occur in a neuron. This will be achieved by firstly‚ defining the purpose of neurons in the body along with a description of the components within a neuron and how they enable information to be passed through the cell membrane and on to other neurons. Secondly‚ the resting potential of a neuron will be explored with relation to the concept of selective permeability and the purpose of the Sodium - Potassium pump. Thirdly‚ the molecular basis of the Action Potential will be
Premium Action potential Neuron
3.1 BIOLOGICAL MEMBRANES 3.1.1 Properties of Cell Membranes • Separates living cell from its nonliving surroundings. • 8 nm thick. • Selectively permeable - allows some substances to cross more easily than others. 4.1.2 Fluid Mosaic Model • Singer and Nicolson (1972) - plasma membrane is a mosaic of proteins dispersed within lipid bilayer‚ with only bilayer‚ the hydrophilic regions exposed to water. Hydrophilic region of protein Phospholipid bilayer Hydrophobic region of protein
Premium Cell membrane Cell Osmosis
Cell Membrane Permeability and Osmosis Experiment 3 Objectives: To demonstrate the mechanism involved in Osmosis; To demonstrate the tonicity of solutions by subjecting the cells to different concentration of solute. To view‚ under the microscope‚ any change in the shape and volume of the cells after subjecting them to different concentrations of solutes; To demonstrate the permeability of cell membrane by subjecting the cells to different solutes; To demonstrate the mechanism involved in
Premium Red blood cell Osmosis Cell membrane
What is an action potential? To put it simply‚ it is a message that is sent down the nervous line. The message is written and is sent from the central nervous system. That message is addressed to muscles or glands. This essay will explain what happens before‚ during‚ and after an interneuron action potential. To accurately define an action potential‚ it is part of the incredible course of events that occur during the firing of a neuron. When a neuron is not firing signals‚ the interior of the
Premium Electric charge Neuron Action potential
The plasma or cell membrane exhibits ability for the cell to discriminate in its chemical exchanges with its environment and this makes cell membrane fundamental to life. This property can only be possible because of the cell membrane’s selective permeability (Campbell and Reece‚ 2002). The structure of the membrane can be best illustrated by the fluid mosaic model where the membrane is said to be a fluid structure with various proteins embedded in or attached to a bilayer of phospholipids (Campbell
Premium Red blood cell Cell membrane
PLASMA MEMBRANE SELECTIVE PERMEABILITY= allowing some substance to cross it more easily than others composed of: Phospholipids Proteins Carbohydrates Cholesterol FLUID MOSAIC MODEL Phospholipids are primary lipids(constantly moving‚ fluidly) AMPHIPATHIC-containing hydrophobic and hydrophilic regions Mosaic part=not made of one thing Freeze-fracture studies:way to view what’s inside FLUIDITY OF MEMBRANE Move within bilayer Most of lipids and some proteins‚ drift laterally
Premium Membrane biology Cell membrane Lipid bilayer