Plant cells interesting features

Plant cells interesting features

Plant cells are eukaryotic but have no centrioles and contains these interesting features such as:

Cellulose cell wall- A strong barrier on the outside of the cell membranes. it is composed of a polysaccharide called cellulose.  it proves shape and rigidity to the cell.

Large permanent vacuole- A large central sac surrounded by a membrane known as a tonoplast and it principally contains water, the main function on the vacuole is to increase turgor pressure  i.e. the extent to which cells are filled with water.

Chloroplasts-  Is an organelle containing fluid stroma and a network of membranes thylakoids which are stacked as grana, The organelle responsible for photosynthesis.

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Microscopes

Types of microscopes:

Light Microscope-  Is a microscope which uses visible light to magnify and illuminate specimens which cannot be seen with visible light.

Transmission Electron Microscope-  Is a type of electron microscope which only uses electrons to magnify a specimen. electrons can go through the specimen.

Scanning Electron Microscope- Is a type of electron microscope which uses electorns to magnify a image of the surface of the specimen only.

Confocal laser scanning microscope- Is a type of microscope which uses a laser light to scan a specimen and the light is absorbed by chemicals and radiated back from the specimen and a laser is lined up in the same direction and can be focused on a small spot.

	Light	Electron microscope
		Transmission (TEM)	Scanning (SEM)
Extra info	Uses visible light to magnify specimens.	Electron beams pass through the specimen	Electron are reflected back from the specimen and are detected.
Magnification	X2000	X500,000	X100,000
Resolution (NM)	200	0.5	10
Benefits	-Inexpensive -short preparation time -can see real life colors -view living specimens	-high magnification -see intracellular details	-High magnification -3D images produced
Drawbacks	-Limited magnification -limited resolution	-very expensive -Hard to use -Images are in black  and white -Hard to prepare specimens	-very expensive -Hard to use -Images are in black  and white -Hard to prepare specimens

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Magnification and Resolution

Magnification and Resolution

To observe biological material we use microscopes, to know the size of the specimens we can use this formula:

The triangle above is a easier way to remember and use the formula just put your thumb over the symbol you want to figure out. 

Magnification: is the extent to which a actual size of an object is enlarged into the image seen through a microscope.

Resolution: is the extent to which two objects can be distinguished as a separate structure.

A helpful mnemonic would be to us ''I AM''

Example:

Q. A microscope has a magnification of X1500 and a RBC has a diameter of 1.05cm what is the actual diameter?

A. Actual size= Size of image/Magnification= 1.05/1500=0.0007cm (7um)

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Inorganic ions

Inorganic Ions

ions are atoms or molecules that have lost electrons (positively charged ions which are cations) or gained electrons (negatively charged ions are anions)

The most common inorganic ions:

Calcium Ca2+= Nervous impulse transmission and is used in action potentials

Sodium Na+= Nervous impulse transmission and is used in action potentials

Potassium K+= Nervous impulse transmission and is used in action potentials

Hydrogen H+= Determination of PH in solution and is used in factors affecting enzyme activity

Ammonium NH4+= Sources of nitrogen for plants used in the nitrogen cycle

Nitrate N03-= Transport of respiratory gases used in the carbon dioxide cycle

Hydrogen carbonate HCO3-= Transport for respiratory gases used to transport oxygen

Chloride Cl-= Transport for respiratory gases used to transport oxygen

Phosphate PO43-= Nucleic acid and ATP formation and is used in nucleic acid 

Hydroxide OH-= Determination of PH in solutions and is used in affecting enzyme activity

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Enzymes (continued I)

Enzymes (continued I) 

A short note:

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Hi All! 

Firstly Happy new year! I really hope 2018 will be good for all of us and we all achieve the best results and learn a lot of things!  I have decided to study enzymes in a in depth topic over the month of January simply because it is a big topic and I am studying it in particular. I have also received many messages asking to post chemistry content and this will be done shortly! Please bear with me :) thanks!!!! 

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Enzyme: Is a biological catalyst (it basically speeds up reactions so they can happen faster)

In metabolism we have seen that each reaction is catalysed and facilitated by an enzyme. Compounds on their own do not react with each other and activation energy is required for the reaction to occur.

Enzymes can facilitate events and enzymes can create the right environment for molecules to interact. Enzymes are biological catalysts and enzymes are almost always proteins. They speed up the rate of reactions by reducing the activation energy required to take place. Often in the absence of the enzymes the reaction cannot take place at all and the enzyme remains unchanged at the end of the reaction,

Enzyme activity= Moles of products produces/ Units of time

The active site is the environment where the reactions takes place and the substrate fits in the active site.

Factors that affect enzyme activity:

-PH

Attraction/repulsion from ionic charges of R groups contribute to the stability of the protein tertiary structure. Changes in PH affect the charge of the R group and thus changes in PH will affect protein structure. Changes in the structure will affect changes in the enzyme function.

-Temperature

-Substrate Concentration 

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