Unit 13, task 1.
P1 – Describe the microstructure of a typical animal cell and the functions of the main cell components. A typical animal cell is seen as a tiny, three dimensional sac which is in fact made up of many components, each as important as the other. The microstructure of an animal cell was in fact uncovered mainly through the use of both cell fractionation and electron microscopy. Each main component has its own, individual function which helps a cell to function and maintains the cell membrane. The components that I will be describing include the cell membrane, nucleus, cytoplasm, mitochondria, lysosomes, Golgi bodies, centrioles, endoplasmic reticulum (both smooth and rough) and ribosomes.
The cell membrane - The cell membrane is also known as the plasma membrane and is located on the surface of all typical animal cells, it is covered by a double layer of phospholipid known as the bilayer (fat cells) on each individual cell. The lipid bilayer is there to help protect the cell from any uncontrolled flow of water, a barrier that is there to mark the boundaries of the animal cell and is made up of two layers which are known as the exposed hydrophilic (water loving) and the hidden hydrophobic (water fearing). The structure of the phospholipid is made up of the polar heads and the nonpolar tails and is known as impermeable. This means that only water and gases can easily pass through it and that it does not allow other molecules to do so quite as easily, this means that both other small and large molecules need to be assisted by other structures to do so. The heads are composed of phosphorus and the tail is made up of a string of carbons and hydrogen’s. The phospholipids sort themselves into the bilayer which is in fact a natural process so therefore does not require any energy to be carried out so that the hydrophobic tail regions are hidden from water and the hydrophilic regions are exposed to it. The phospholipid bilayer is seen as the basic structure of membranes and contains proteins within. This structure is known as the fluid mosaic model. The fluid part is because it allows all of both the individual proteins and phospholipids to move around in all directions, almost like a liquid. The mosaic part is for the pattern which is produced by the protein molecules that are scattered around, when the membrane is seen from a top point of view (from above).
Centrioles - The structure of the centrioles is seen as a spiral arrangement also known as cylindrical and they are usually found adjacent to the nucleus within a typical animal cell. There are usually two centrioles, known as a pair, which lie perpendicular to each other and together they form a centrosome. Each individual centriole is said to consist of nine microtubules. The main function of the centrioles comes into place during the divisions of cells as they play the part of organising the separation of chromosomes. They also replicate to form two centrosomes during meiosis and mitosis in the interphase stage of cell division.
Mitochondria (plural) – Mitochondrion (single). A typical animal cell is said to have 1000 -2000 mitochondria. Mitochondria are known as the power stations of a cell. Their main function is to provide energy to cells in order for them to be able to move, produce proteins and divide to make new cells. Mitochondria have their own DNA and ribosomes and the structure of them is made up of two membranes one of which is folded up inside (convoluted inner membrane) and the other is a smooth membrane on the outside. This forms Cristae which are used to combine sugar with oxygen in order to form ATP known source of energy for a cell. This is done through the use or oxygen to release energy from the cell. This is known as aerobic respiration and is when glucose is respired completely into carbon dioxide. The membrane which is folded up inside in fact increases the area of where chemical reactions can take place. The cells in...
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