How Do Alkanes React?

Alkanes are less reactive then alkenes. (All single bonds.)

There are four electrons in the area between the two carbons, which is called an area of high electron density.

To make a double bond, you have to distort orbitals, which means, the bond is strained, and would prefer to like, 'burst out', as such, and form single bonds.

Double bonds attack things, as they are really really unstable.

Breaking double bonds - Addition Reaction.

Electrophyllic = The electron loving one, positive
Nucleophyllic= The nucleus loving one, negative.

When drawing the examplesof electrophyllic addtion reactions always:

Draw the molecules being polar.

Include ALL arrows. To the right place.

Include the second structure. (With the positive carbon.)

Show the final product.

Isomer:

• Structural
  - Chain (alter the carbon chain) -Positional (move functional group.) -Function (functional group changes.)
• Stereoisomers.
  -Geometric (E/Z)

Thoughts? Remember, correct me if I'm wrong. I'm only an AS student myself. (:

-Nin.

Chem: Geometric isomers and that. (:

Electronslive in orbitals. When an S and P orbitaljoin together, that makes a single bond.

Stereo Isomerism requires a double bond, and each carbon either side of it, to have two different things on it.

This type of stereo isomerismis known as geometric isomerism.

The two geometric isomer types are 'E', and 'Z'.

E/Z goes by molecular mass of things attached.

Z= The highest priority atoms/molecules TOGETHER.
E= The highest priority atoms/molecules OPPOSITE.

By highest priority, I mean highest mass.

So, a Z (together), would be, for e.g.:
H- -H
C=C
Cl- -Cl

(the '-' means a diagonal bondto the C, not a -ive ion.)
This would be because on both C's, the Cl has the biggest mass, and is therefore of priority, and they are both together on the same side.

An E would be:
Cl- -H
C=C
H- -Cl

Because, once again, the Cl is of greater mass on both Carbon, and they are therefore, of priority,andthey are at diagonals.

Instructions/Checklist for recognising Geometric Isomers:

1. Double Bond?
2. Does each carbon have two different things on it?
3. Which has the bigger mass on either side?
4. Are these together or opposite?

-Nin

More Chloroplast stufff. :D

Chloroplast envelope- a highly selective double membrane.

Grana- Stacks of about 100 disk like structures called thylakoids. Thylakoids contain Chlorophyll (the photosynthetic pigment.) Grana are linked by lamellae, (pieces of thylakoid membrane). The first stage of photosynthesis takes place on the grana.

Stroma- is the fluid filled matrix where the second stage of photosynthesis takes place.Contains lots of enzymes.

Chloroplasts contain ribosomes and DNA to manufacture the proteins needed for photosynthesis.

DNA contains genetic code.

CO2 and Water go in via the membrane, oxygen and glucose go out.

Plant Cell Wall:
Cellulose- makes molecules bonded to form micro fibrils,which stack and form cell wall. Cellulose is a polysaccharide made from Beta Glucose.

Many micro fibrils make a fibril.

Cell Wall:

• Consists of microfibrils of the polysaccharide CELLULOSE in a matrix.
• They are very strong.
• They give the wall mechanical strength, and prevent it form bursting due to osmotic pressures.
• This allows water to pass along it.
• The middle lamella (thin layer) marks the boundary between the cell walls.

Cellulose: Straight polysaccharide chains of Beta Glucose. The chains hydrogen bond together, forming very strong fibres. They are insouble. Use: Supports andstrengthens plant cell.

Insoluble, important as: won't affect water potnetial.

Amylopectin: Alpha glucose helix with branches. The branches give more end points for hydrolysis to take place, and therefore, it is broken down quicker.

Glycogen: A carbohydrate foundin animals. (AN: Yeaaaa!Found it.xD!) It is alpha glucose, and therefore forms a helix. It has more branches, and these branches have side branches. This means thereare even more points for Hydrolysis,andisit broken down even quicker, as Amylopectin is in plants, and they don't do as much, but Glycogen is in animals, which are far more active, and therefore, it needs to be broken down quicker.

More notes from before exam.

Water Soluble = Polar molecule, therefore, cannot pass through phospholipid bilayer. Goes through protein channelsas they have hydrophyllic linings.

Lipid Soluble = Non Polar, /will/ pass through (directly) the phospholipid bilayer.

Boiling an enzyme will denature it, therefore, it looses it's tertiary shape, and cannot function. The substrate will not be hydrolysed.

What would happen to need a coronary by-pass thingy:

1. Atheroma would form (fatty, cholesterol build up in lungs.)
2. This would be on the lining/epithelium/lumenof the coronary artery (all good words to use, those.)
3. This reduces/obstructs the blood-flow.

Higher salt intake= Higher BP, because... Ion intake (Na+,Cl-) increases, therefore, water potnetial is lower, and water then moves into the blood, increasing it's volume, andtherefore, proportionally, the pressure increases.

Three components of a triglyceride = Three fatty acids and a glycerol molecule. In a condensation reaction. This is opposite to Hydrolysis.

Disulphide bond- strong, covalent bond between two sulhpur atoms.

The Alpha Helix, and the Beta Pleated Sheet are held together by hydrogen bonds.

When speaking about variables, don't use the word 'amount', but specify, so: Temperature, Volume, pH, Concentration, or even Age.

Don't use the word 'size', use 'volume'.

Glycogen is a storage carbohydrate. I think it is in animals,not 100% sure. Will check andpost later. (:

Carbon dioxide is not produce as quick with lactose as with glucose, as glucose can be used immediatley, whereas an enzyme must be synthesised for lactose.

Scar tissue reduces the surface area for gas exchange through damage.

'Human Error' is generally too vague a statement.

Litigation = Sueing the company.

Why antibodies are much faster when the same antigen enters the body on a second occasion:

• Memory cells are produced during first respone/exposure.
• Memory cells recgonise the antigen immediatley, and develop into plasma cells.
• This is by cloning.
• Quicker response, as the production of plasma cells is quicker.
• More plasma cells, therefore, more antibodies, = more chance of colliding with, combining with pathogen.

Myocardial Infarction = Heart muscle dying.

That's all, folks :D

-Nin. ^_^

Odd Notes from end of early January.

A control group allows you to make valid comparison of the results.

B Lymphocytes respond to specific antigen, divide rapidly and produce clones. Some of the clones form plasma cells, which secrete antibodies. Some of them form memory cells, which become active on the second exposure to the same antigen, and this means they produce the antibodies faster, and in larger quantities.

-Nin. (:

Random Chem Unit 1 Notes.

Group 1+2= metals.

Sodium has a lower BP (boiling point) then Magnesium,astheyare both metallic, but sodium only puts one electron into the delocalised sea, but Mg puts in two, and also Mg's are smaller,and easier for the electrons to attract together, so it therefore, has bigger electrostatic forces, and the melting point is higher.

When drawing Hydrogen bonds:

• Lines must be straight.
• All dipoles must be shown.
• Must have the correct amount of lone pairs drawn on.

Ethanol: C2H6O

If it says economic reasons, looking for something about 'efficiency'.

Structural Isomer: Same formulae,but the atoms are arranged differently.

Thoughts?

Nin.

Unit Two Stuff. Bio, Pallisade Cells and that.

DNA: Is the code for everything that goes on in the body.

The upper epidermis. Light can get through it, and acts as a protective layer.

Photosynthesis: Carbon Dioxide+Water=(with energy from light)Glucose+Oxygen.

The Mesophyll has less chloroplasts then the pallisade mesophyll, but still has some and partakes in photosynthesis.

Pallisade Cell- In a leaf, the second layer down. The function is to photosynthesize and produce glucose for the plant.

Starch Grains (the little dots on the cell thingy.), are a temporary store in the leaf, and store glucose.

Plants have a permanent vacuole. It is filled with cell sap, which is a sticky mix of water and salts.it allows water to move from cell to cell as there are different water potenitals.

Chloroplasts:

• Have a double membrane: inner and outer.
• Inter membrane sapce inbetween these.
• Stack of structures. The single disc/pancakes type structure is a thylakoid, a stack is a granum, and lots of stacks stacked is a grana
• The stacks are connected by Lumella (thylakoid membrane?), for transport/communication.
• The light is ... recepted/taken in (can't think of a better word >_<) ... in the thylakoid membrane.
• The enzymes needed for photosynthesis are in the stoma. (Plasmy bit between stacks and stuff (: )

And that's all I have from my first unit two lesson. :D

Comments and corrections please? ^_^

Nin.

So, not many posts in a while. (:

I've been going through and typing up all my notes on my laptop, which has a really bad internet connexion. I will, however, be posting these when I transfer them onto my computer/a college one. (: Expect a bunch of unit one notes in the near future. I'm also going to go through and tag posts and find things easily. (: 'Kay?

Updates will be made.

I also will actually make chemistry notes this term. Might also make notes on last unit as well for revision's sake.

Exams go well?

Nin. (:

Enzymes and stuff.

Objs:
-What are enzymes
- Describe models to illustrate functions
-What do enzymes do?

Starch + Water = Amylase = Maltose

Lipid + Water = Lypase = Fatty Acid + Glycerol

Protein + Water = Protease = Amino Acids

Sucrose + Water = Sucrase = Fructose and Glucose

Maltose + Water = Maltase = Glucose

Big molecules being broken down into smaller ones = hydrolysis reaction, hydro: there should therefore, before the reactant should be water.

Substrate reacted with an enzyme = Products.

Enzyme = Biological Catalyst = speeds up reaction in living organisms

The body produces Hydrogen Peroxide. It is toxic for us, but we have an enzyme, catalayse, which breaks it down to make water and oxygen.

Molecules have more kinetic energy, collide more, but this is by heating. Can't heat up hydrogen peroxide, is in body, is why enzymes are handy.

An enzyme works by lowering the acitivation energy needed, which is a barrier to the rate of reation, therefore, the enzymes speed it up. (See catalyst.)

What do enzymes do?

Speed up reactions by lowering activation energy needed, which acts as a barrier.

Why are Enzymes Catalysts?

Substrate Energy is always higher then product energy. The barrier gets lowered with an enzyme. Enzymes are catalysts as they lower the activation energy required to drive a reaction.

The nature of Enzymes:

They are globular proteins. Globular proteins have a globular shape. If the shape is wrong, it won't function properly, if the tertiary structure is wrong. The tertiary fold relies on primary, as it is defined by the sequence of amino acids.

Enzymes are usually quite large, only a small area is important though. The active site: a specific shape due to the way it folds up. If something affects the active site, the enzyme will not be functional.

Enzyme + Substrate = Enzyme Substrate Complex + Products.

The substrate and enzyme have COMPLIMENTARY shapes. Like jigsaw pieces, they fit together, but they aren't identical.

At the end, the enzyme is unchanged and can be reused, whereas products diffuse away.

Enzyme + Substrate = Enzyme Substrate Complex, REACTION TAKES PLACE = Enzyme + Products.

Enzymes are:

• Proteins of high molecular weight.
  
• A bio-catalyst.
  
• Sensitive to temperature changes.
  
• Sensitive to pH
  

Enzyme and substrate have to hit at right force AND be of complimentary shape.

Models...

Lock and Key model, 1894, if there's not a specific key in the lock, the door won't open style metaphor. In an enzyme catalysed reaction the enzyme bonds to the substrate to form a complex.

Induced Fit Model, a glove is vaguely the same shape as a hand, when a hand is in the glove the fit 'induces' to fit it. Explains that the enzyme changes shape, and takes into account that they have some flexibility.

Once the substrate has bound to the enzyme, that bind tells the enzymes to change the shape to therefore become a perfect fit. Therefore, a reaction can't take place until the induced fit has happened.

Oh, and this was a side note, 'Saw chancges take place with x-ray defraction, therefore, better model.' Don't have a clue what I was on about. Suggestions?

-Nin.

A homework that I thought may be of use. Osmosis and that,

Active Transport - is energy requiring transport of molecules pr ions against a concentration gradient. It needs energy from respiration. An example is the resorption of Na in the kidney.

Exocytosis - is a process exporting large molecules from the cell. A secretory vessel is formed, and it is a type of bulk transport. An example of this is the secretion of digestive enzymes by cells in the pancreas.

Facilitated Diffusion- is diffusion through hydrophyllic protein channels. A protein carrier transports the molecules down a concentration gradient. It is a passive process. An example is the movement of glucose into cells.

Osmosis- is the net movement of water molecules down a water potential gradient through a partially permeable membrane. It is a passive process. An example of this is a red blood cell losing water when placed in a hypertonic solution.

Simple diffusion - is the net movement of molecules from a region of higher concentration to lower concentration down a concentration gradient. The molecules or ions move down a concentration gradient. Therefore it is a passive process. An example of this is the movement of respiratory gases between the alveoli and blood capillaries.

Phagocytosis- is the uptake of solid material into a cell. It is a type of bulk transport and a phagocytotic vessle is formed. An example of which is a white blood cell engulfing bacterium.

Pinocytosis- is the uptake of liquid into cell. It is a type of bulk transport, and small vacuoles or vesicles are formed. An example of this is a human egg taking up nutrients that surround it.