Currently unavailable: for regular students
Degree: Biomedical Sciences with Management (Medical Biology) (Bachelors) - Edinburgh University
|Biology||A Level||£20 /hr|
|Human Biology||A Level||£20 /hr|
|Human Biology||GCSE||£18 /hr|
|Maths||13 Plus||£18 /hr|
|Science||13 Plus||£18 /hr|
|Maths||11 Plus||£18 /hr|
|-Personal Statements-||Mentoring||£20 /hr|
|Before 12pm||12pm - 5pm||After 5pm|
Please get in touch for more detailed availability
Diffusion is the net passive movement of particles (atoms, ions or molecules) from a region in which they are in higher concentration to regions of lower concentration. It continues until the concentration of substances is uniform throughout. Since the movement is always down the concentration gradient, it requires no energy.
One major example of diffusion is gas exchange for respiration — this is the process used in oxygen entering a cell, and carbon dioxide leaving. The blood system in humans continually brings more oxygen to the cell and takes carbon dioxide away, maintaining a high concentration gradient.
Fick's law is used to measure the rate of diffusion. It states that the rate of diffusion across an exchange surfaces (e.g. membrane, epithelium) is = (surface area x difference in concentration gradient) / thickness of surface. The larger the area and difference in concentration is and the thinner the surface is, the quicker rate the diffusion has. Moreover, temperature increases rate of diffusion due to increasing kinetic energy.
An example of animal's body part that increases the rate of diffusion is microvilli. They are extensions of plasma membrane that increase the surface area of the membrane and thus increase the diffusion rate.see more
In order to find the unknown variables x and y we need to simplify these equations in the way that will make it possible for us to get rid of either x or y variable, and make it easier to solve the remaining variable.
This method is known as Elimination, which is one of the methods how to solve a system of linear equations.
We need to rewrite the equations so that when the equations are added, one of the variables is eliminated. In simple terms, we need to get same number of x's or the same number of y's, but with an opposite sign, in both equations.
(1) 2x - 3y =13
(2) 3x + y = 3
You can multiply equation (2) by 3, then add equations (1) and (2) to form equation (3) with just one variable.
(2) 3*(3x+y) = 3*(3)
(2) 9x + 3y = 9
(1) 2x - 3y = 13
(3) 9x + 3y + 2x - 3y = 9 + 13
(3) 11x = 22
(3) x = 2
Then substitute our value for x back to one of the original equations and find what the value of y is.
2x - 3y = 13
2*(2) - 3y = 13
4 - 3y =13
- 3y = 9
y = - 3
Afterwards we can check our results by substituting our variables back into the original equations.
2*(2) - 3*(- 3) = 13
3*(2) + (- 3) = 3
Problem solved :)see more
1) The nerve cell, also referred to as a neuron, has several parts that are important for its function in the nervous system. These parts are:
Soma - or a nerve cell body, contains nucleus and other organelles. It is also responsible for synthesis of neurotransmitter.
Dendrites - are branching extensions from nerve cell soma. They get stimulated by other neurons and transmit the impulses towards soma.
Axon - a single extension that extends from soma to the target cell. Myelinated axon is surrounded by Schwann cells (myelin sheath) with gaps of nodes of Ranvier in between them. There are terminal boutons at the end of the axon where the synapse is located.
2) There are 3 main types of neurons:
Sensory neurons (afferent neurons) transfer information from the external environment to the central nervous system (CNS).
Motor neurons (efferent neurons) transfer information from the CNS to external environment, to effector organ e.g. gland or muscle.
Interneurons, or association neurons, process information in the CNS and transfers the information from one neuron to the other within the CNS.see more