* An electrogenic pump is a transport protein that generates voltage across a membrane * Animal- sodium/potassium * Plants- proton pump Understand how a co-transporter works. Where you likely find one? Understand how large molecules and particles are transported across membranes including the role of Vesicles. What is meant by endocytosis? There are several types – what are they and how do they differ?
Unit 13 P2 Describe how materials of different states pass into and out of cells. The cells plasma membrane is not only used for structural purposes. Its functions to allow certain substances in and out of the cell. It can allow other substances into the cell against the concentration gradient or allow other substances (for example waste) out of the cell. There are two ways that the cell can transport substances; passive transport processes and active transport processes.
Analyze the polarity of the different regions of a phospholipid molecule. Use the model of the phospholipid to describe the structure of the cell membrane. How do water, phospholipids, and proteins interact to produce the cell membrane? * Analyze the polarity and water-solubility of the different regions of the globular protein floating in the phospholipid bilayer membrane shown below. The protein molecule is able to float in the membrane – part of it is embedded in the membrane, part of it sticks into the cytoplasm, and part of it sticks out into the aqueous environment of the cell.
Mineralocorticoids, mostly aldosterone, are essential to regulation of electrolyte concentrations of extracellular fluids. 2. Aldosterone secretion is regulated by the renin-angiotensin mechanism, fluctuating blood concentrations of sodium and potassium ions, and secretion of ACTH. 3. Glucocorticoids are released in response to stress through the action of ACTH.
Neurons, electrically excitable cells, respond to chemical and mechanical stimuli by producing small changes in the resting membrane potential (measured in mV) called graded potentials. Graded potentials, if large enough, may produce an action potential. Action potentials are generated when the resting membrane potential (usually -70 mV to -55 mV) at the axon hillock is depolarized above threshold (usually-55 mV) by depolarizing graded potentials. Action Potential An action potential is a large change in membrane potential. It is used to communicate over large distances.
trigger zone 2. Where was membrane potential measured? axon 3. What was used to measure membrane potential? voltmeter, patch clamp equipment and electrodes Results Table 3: Membrane Potentials at Different Stimulation Voltages, by Location.
The solutes are called electrolytes, which maintain healthy bodily functions. When an electrolyte dissolves it breaks up into ions. There are millions of electrolytes within a cell. Water moves inside and outside the cell, with osmotic pressure, which is the force that pulls fluid from one place to another. The level of osmotic pressure is equal in the intracellular fluid, and the extracellular fluid.’ (Study.com, 2015) ‘Osmotic pressure is vital within the human body because it allows water to enter a cell if there is lack of water, and vice versa, if there is too much water within one cell, the osmotic pressure will allows the electrolytes to exit a cell.’ (Study.com, 2015) ‘Intracellular fluid has important functions, it transports food within the cells, it also brings waste products from the cells so that they can be picked up and excreted from the body, and it maintains the shape and size of the cell.’ (Nursing411.org, 2015) ‘Extracellular fluid is located outside the body cells.
In other words, neurotransmitters are the messages that nerve cells send out, and they cross the gaps between each of the cells. When released by the sending neuron, neurotransmitters travel across the synapse and neuron. Therefore, they influence whether that neuron will generate a neural impulse or not. B) An agonist mimics neurotransmitters functions by binding to receptor sites and stimulating the sending neuron. C) An antagonist does the opposite of agonist.
The energy for this process is supplied by the hydrolysis of ATP using the enzyme ATPase and a specific protein channel in the membrane. Active transport is the movement of substances from where they are less concentrated to where they are more concentrated. It is undertaken by carrier proteins in cell membranes, which move specific molecules or ions against the concentration gradient using energy supplied by ATP. Cells have many adaptations to allow them to facilitate active transport; they may have carrier proteins in the cell surface membrane designed to transport particular molecules or ions or possess many mitochondria to supply the required ATP. Active transport requires energy in the form of ATP and protein carriers to move the molecules across the membrane.
c) How does one nerve cell communicate with another? - Nerve cells communicate with one another through neurotransmitters. 2. a) Explain what neurotransmitters are? - Neurotransmitters are chemical messengers that cross the synaptic gaps between neurons. When released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing where that neuron will generate a neural impulse.