A comparison of Light microscope and electron microscope

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Light Microscope

Electron Microscope

The light Microscope uses compound lenses and light to magnify objects. The lenses used bend or refract light. This enables the objects beneath them appear to be closer.

These Microscopes are normally used within a a school setting and are cheaper to purchase and use. They are unaffected by magnetic fields. The use and preparation of material is quick and simple and only requires little expertise, it can observe natural colour.

This Microscope can magnify objects up to 2000x, its depth into the field is restricted compared to Electron. The resolution is the magnitude of the zoom, the clarity on this scope when zoomed affects how clear the image can be seen.

There are two types of Electron Microscopes, one is a Scanning Electron Microscope, it allows the person viewing to see things that are too small for the light microscope to pick up. This Microscope doesn’t use light waves to magnify objects, it uses negatively charged electrical particles (electrons). The are large and can only be operated in special rooms, they are affected by magnetic fields and only function in black and white and needs considerable expertise to operate.

The Second is The Transmission Electron Microscope, it still uses electrons, but instead of scanning the surface of an object, the electrons are passed through very thin specimens to see the image. Commonly used by scientists. It can magnify objects up to two million times with a high resolution making the clarity very clear to the eye and makes it possible to investigate a greater depth of field. Resolution means the greater the zoom, clarify is how clear a object can be seen.

Organelle

Function of Organelle

Ribosome

Ribosomes function to read the code represented by messenger to the RNA which is formed from the cell’s main DNA. Proteins are synthesised from this code meaning the synthesis of all new proteins occurs from the ribosomes.

Chromatin

Chromatin’s main functions are to package DNA into smaller volumes to fit in cells and to reinforce the DNA macromolecule to allow mitosis, the also prevent DNA damage and control expression and DNA replication.

Endoplasmic Reticulum Rough

Has many general functions, it folds the protein molecules in sacs called cisternae and transports synthesised proteins in vesicles to the Golgi apparatus.

Endoplasmic Reticulum Smooth

This is associated with the production and metabolism of fats and steroid hormones. The Endoplasmic Reticulum smooth is called this as it is not studded with ribosomes and is always associated with smooth slippery fats, for example cells in the testes, ovaries. It also carries out metabolism of carbohydrates, drug detoxification and attachment of receptors on cell membrane proteins.

Flagella

The main role of the Flagellum is locomotion, it also has a function which is a sensory organelle, its sensitive to chemicals and temperatures outside the cell. It moves liquid past the surface of the cell, for instance single cells, sperm, enables them to swim.

Golgi Apparatus

The Golgi apparatus modified and sorts the packaging of proteins for secretion. It transports liquids around the cell and creates lysosomes. Cisternae are the sac and fold of the Golgi Apparatus.

Mitochondria

Mitochondria act as the power of the cell, they are organelles that work as a digestive system. They take in nutrients, break them down. They crete energy rich molecules for the cell itself. They help the cell to respire.

Nucleus

The Nucleus’s main function is to control the gene expression and replication of DNA during a cell cycle.

Lysosome

The Lysosomes hold enzymes that have been created by the cell. Lysosomes digest things such as food, they also digest a cell and help with its breakdown after it has died.

C,

Red Blood Cells (erthrocytes) , they are a Biconcave disc shape it has a high surface area to volume ratio, it contains haemoglobin for oxygen absorption. There is no nucleus so it allows more room for haemoglobin. They have a concave hollow on each side. With their flat shape it allows them molecules to be closer to the surface of the cell. They are so flexible they can bend and fit through even small capillaries enabling them to do their job of providing oxygen around the body.

Ciliated epithelium- Micro cilia give large surface area for absorption of molecules. For example human skin. It is broken down into two parts, Cilia are hair like structures that sit on top of the tissue, they move back and forth to help move things. The Epithelium is a tissue type, very thin and as mentioned before covers structures. For example, the The Cilia that line your respiratory tract, catch particles with its hair, then move them out, avoiding them going into the lungs, this then triggers a sneeze, without its structure of hair, it would not be able to catch these particles and function correctly.

Sperm cells- Have a long tail for motility. Pointy head to allow them to bury into an ova. Mitochondria for energy. The structure helps define the function, for example a sperm cell has flagella (a tail) in its structure and this also defines its function which is to move and travel, without this structure it wouldn’t be able to function. It enables the cell to move past things and with its smooth like surface make it to the reproduction system enabling reproduction.

TAQ 3

‘The cell membrane is a fluid mosaic model made up of lipids and protein molecules.’

Fluid-mosaic model describes the plasma membrane for animal cells. It’s plasma membrane that surrounds these cells have two layers, better known as ‘a bilayer’ of phospholipids (lipids) , known as fats with phosphorous attached, The lipid bilayer extends right up to the membrane protein, with a thickness around the protein. A lipid

molecule will remain in the shell around a protein for only a short period of time. At body temperature the structure of the plasma membrane is like a fluid, i.e like vegetable fat. Each molecule has a head that attracts to water and a tail that repels water. Both parts of the plasma membrane have two heads that attract water pointing outwards, and the tail that repels for the inside of the bilayer. This makes proteins and other substances for example cholesterol get embedded in the plasma membrane, when this happens it can make the the membrane more stable and helps it from solidifying when the temperature of a persons body goes low. Say your body temperer drops and a person is very cold, freezing, this process keeps a person from actually freezing.

TAQ 4

Active Transport

Active transport, uses energy to move substances against a concentration gradient or across a partially permeable membrane. Active transport transports a special protein and the cell membrane picks up the particle on one side of the membrane. This protein then moves through the membrane and releases the particle on the other side.

Active Transport moves substances into cells and out of cells. Cells do a lot of active transport. Active transport for example plays a key role in the kidneys, it take and hangs on to substances the body needs like glucose and sodium.

Passive Transport (Diffusion)

Passive Transport also known as diffusion is the spreading out of articles of a gas or a substance in a solution. It happens due to random movements of the particles. If the temperature is higher, the particles will move faster and the diffusion takes place. Diffusion happens because of the result of the overall movement of particles from an area of high concentration to an area of low concentration down a concentration gradient. If there is a big difference, diffusion will happen faster then is it was smaller. Diffusion plays a key role in the body for movement, for example the movement of oxygen from the air to into the blood stream and CO2 out of blood into the air in the lungs.

Osmosis

This happens when two solutions are separated by a partially permeable membrane.

This membrane lets some particles through but not others. These cell membranes are partially permeable. Substances such as water can move through these membranes but particles like sugar molecules can not.

Osmosis stand for the movement of water, the movement of water by osmosis is the main reason why its important to control the water balance in the body.

Feature

Diffusion

Osmosis

Active Transport

Use of energy

Does not use metabolic energy, it moves ions from high concentration to low in the form of ATP

Uses energy to move water through partially permeable membranes from a dilute soloution( high concentration of water) to a concentrated solution (low level of water)

Uses a ion pump as energy to move ions in and out of cells, it uses the energy of 1 ATP molecule.

concentration gradient

This moves along the concentration gradient, the gradient is from high to low.

This moves through two soloutions separated by a partially permeable membrane down a concentration gradient from a dilute solution.

Moves against the concentration gradient which is a low concentration to high.

Typical Molecules Transported

Moves such things as glucose molecules and protein Molecules.

Moves water particles across membranes.

Can move CO2 particles out of the lungs in the respiratory system.

Examples in body

Can be found int he lungs and respiratory system.

Osmosis can occur in all body cells throughout the body, hence can take place in all organs. Kidneys for example, bladder.

This can take place in the Kidneys and also in the digestion system, intestines.

Type of Tissue

How the structure of the tissue is linked to the function

Nerve Tissue

Nerve tissue is made up of two subtypes of tissue, Neurons and Glial cells, its tissue is wet and compacted like noodles, Its structure helps it entwine around the areas it lives, like the spinal chord, brain ad any other nerves, therefor enabling to receive and conduct impulses alloin bodily functions.

Muscle Tissue

Muscle tissue is made up of three types, smooth, striated and cardiac muscle. Started is put into two groups, skeletal and cardiac. Cardiacs structure of tissue is long thread like cells,it forms walls and enables the heart to pump blood therefor functioning to protect vital organs. As well as the skeletal muscles, long in shape allowing protection of the bones and physical movement. Smooth muscle is different it fits and moves into walls of hollow internal structures. Its used when pressure is required, its normally a involuntary action, its structure allows organs to expand and contract.

Connective Tissue

Connective tissue is made up of cells, ground substances and fibres. It has fewer cells and large amounts of intercellular material unlike epithelial. Its structure helps it to do serval functions, it helps connect things, support and protects other tissues from damage.

Epithelial Tissue

This type of tissue is tightly packed cells packed together in sheets and has very little intercellular material between them. It has no blood vessels, and is single layer thin, with its shape and compactness its help protect the body from different elements, it arms in thickness depending on the organ. There are many different types of this tissue where the are found in different parts of the body.

TAQ 5

TAQ 6

THE HEART

The tissues that make up the organ of the heart are

  • Cardiac muscle, there are three main types, skeletal,smooth and cardiac muscle.
  • It also contains nervous tissues, this conducts the hearts electrical signals to make it contract in a co ordinated manor.
  • It also contains Epithelium tissue, mostly from the blood vessels which supply the heart with oxygen and nutrients.
  • The heart also has Fatty tissue, this protects the heart and offers emergency engross supplies.

The heart is a special organ, it is a muscle that contracts regularly and continuously, it pumps bl""ood to the body and to the lungs. The action of pumping is caused by the flow of electricity through the heart which repeats itself in a continuous cycle.

The heart is part of the circulatory system, its responsible for transporting materials throughout the entire body. The system transports water, nutrients and oxygen to billions if cells around the body and also carried away waste, like CO2 that our cells produce. This system travels throughout the whole body connecting to all body cells.

THE"" LUNGS

The lungs are made up of

  • Connective Tissue
  • Muscular Tissue
    • Epithelial Tissuee

The function of the lungs is to help the oxygen from the air we breathe in enter the body and enter red blood cells. These red blood cells carry that oxygen around the body and give the supply of oxygen to cells in our organs and tissues. The lungs also help remove and get rid of CO2 gas in the lungs out of out body.

The lungs are part of the respiratory system, they are the main organs of this system, in this system the lungs take in oxygen and move it around the body, whilst it removes carbon dioxide as we breathe out. Red blood cells pick up the oxygen and take it to the parts of the body which need it. They drop of the oxygen to the cells which need it and pick up the CO2 which is a waste gas produced by our cells, the red cells take it back to the lungs where we exhale it out. The respiratory system means breathing. Without this system we would be unable to live.

d)

These two systems work together in order to maintain the body working, the respiratory system takes in oxygen from the atmosphere then the oxygen travels through the bloodstream by allowing it to move across the membranes of the lungs into the blood vessels. The circulatory system then carries oxygen to all the cells in the body and picks up carbon dioxide waste, which it returns to the lungs. Carbon dioxide diffuses from the blood into the lungs, and you exhale it into the atmosphere, without these two systems one wouldn't be able to function with out the other, with the heart, the core of th body pumping and functioning, the cells wouldn’t be able to reach the rest o the body, and without the heart pumping the lungs would be unable to contract and bring in air. All the organs in the body can’t function without the other doing its job.

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