Learning with Mixture

Learning with Mixture

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07/06/2021

🧪🥃🧂SEPARATING TECHNIQUES 🧪🥃🧂

SEPARATING SOLID/LIQUID MIXTURES.
If a solid substance is added to a liquid it may dissolve to form a solution. In this case the solid is said to be soluble and is called the solute. The liquid it has dissolved in is called the solvent. An example of this type of process is when sugar is added to tea or coffee or water. Sometimes the solid does not dissolve in the liquid. This solid is said to be insoluble.
1.Filtration🥃🕸️
When a cup of tea is poured through a tea strainer you are carrying out a filtering process. Filtration is a common separation technique used in chemistry laboratories throughout the world. It is used when a solid needs to be separated from a liquid. For example, sand can be separated from a mixture with water by filtering through filter paper.It is important when filtering not to overfill the filter paper. The filter paper contains holes that, although too small to be seen, are large enough to allow the molecules of water through but not the sand particles. It acts like a sieve. The sand gets trapped in the filter paper and the water passes through it. The sand is called the residue and the water is called the filtrate.
2.Decanting🧪🧪🧪
Vegetables do not dissolve in water. When you have boiled some vegetables it is easy to separate them from the water by pouring it off. This process is called decanting. This technique is used quite often to separate an insoluble solid, which has settled at the bottom of a flask, from a liquid.

20/04/2021

3. The epithelium (lining) of the villi is very thin so that soluble sub-stances can easily pass through. The membrane of each epithelial cell Iining the outside of the villus is also folded to form microvilli. 4.There are many mitochondria in the epithelial cells lining the small intestine to provide energy for the uptake of digested food by active transport.
5. The ileum has an extensive blood supply and lymph capillaries, called lacteals, to pick up molecules produced by digestion and transport them away from the gut.The blood rapidly removes molecules absorbed by the cells lining the villi.This helps to maintain a steep diffusion gradient from the lumen of the gut to the blood stream down which molecules can diffuse. Some sub-stances, such as sodium ions, are absorbed by active transport. Fatty acids and glycerol are absorbed into the lacteals, part of the lymph system. Water and vitamins are also absorbed in the small intestine.Glucose and amino acids are carried in the blood through the hepatic portal vein to the liver. Here they may be stored temporarily or processed by the liver before being transported to other body tissues. Some fatty acids and glycerol may also be transported in the blood but most of the molecules pass into the lacteals. They are then transported through the lymph system and into the blood stream. At the end of the small intestine are the caecum and appendix. These are very small in humans and play no specific role in digestion. However, the caecum plays an important role in the digestion of cellulose in herbivorous mammals such as rabbits.🐰🐇🐇🐇

13/04/2021

Biology 🐉🦕🦖🦖🌏🌏🌍
v)Ribosomes: These are small round structures in the cell where protein synthesis takes place.
Some ribosomes float freely in the cytoplasm while others are attached to the rough endoplasmic reticulum.
(vii)Endoplasmic Reticulum:This is a network of membranes used for transportation of substances within the cytoplasm. There are two types of endoplasmic reticulum, namely smooth endoplasmic reticulum and rough endoplasmic reticulum. Rough endoplasmic reticulum has ribosomes on its surface and transports proteins. Smooth endoplasmic reticulum has no ribosomes on its surface and transports lipids.
(viii)Golgi Bodies: These are a pile of flattened vesicles which modify and carry proteins such as enzymes from the sites of synthesis to the sites of reaction. They are collectively called the Golgi apparatus.
(ix)Chloroplasts: These are oval-shaped structures found in plant cells. They carry out photosynthesis. They contain a green pigment called chlorophyll which absorbs light energy for photosynthesis.
(x)Vacuole: This is a fluid filled space inside the cytoplasm of a plant cell. It contains a fluid called cell sap (a solution of sugars and salts in water) and is surrounded by a membrane called tanoplast. The concentration of the cell sap plays a role in the movement of water into and out of the cell.
(xi)Cell wall: This is the outermost boundary of the plant cell. It is made of a substance called cellulose. It is important for protection against damage and prevention of bursting when the plant cell gains a lot of water. It also gives shape to the plant cell. It is fully permeable to all substances.

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