Sunday, December 26, 2010

Neurotransmitters

Acetylcholine


  • is the first discovered neurotransmitter
  • acts as a chemical transmitter in both the parasympathetic and central nervous system
  • stimulates muscles and excites the nerves by delivering Na ions
  • too much can cause decreased heart rates, but too little can cause motor dysfunction

Serotonin

  • synthesized from  A.A. tryptophin
  • involved in transmitting nerve signals
  • it affects our mood and keeps our emotions under control 
  • serotonin is used as medication to alter patient's moods 
  • foods that increase serotonin levels: dark chocolate, whey protein, nicotine

Endorphins

  • endorphins can be found in the pituitary and within the nervous system
  • it works to relieve pain, leading to pleasurable feelings
  • as a result, stress and pain are the two most common factors that lead to release of endorphins within the body
  • chocolate enhances secretion of endorphins

Norepinephrine

  • a stress hormone and neurotransmitter
  • main purpose is to relieve stress (secreted by the brain)

Saturday, November 13, 2010

Photosynthesis

Non-Cyclic Electron Flow

1) takes place in the thylakoid of the chloroplast, where cholorophyll is housed
2) sunlight is captured by chlorophyll and enzymes in the thyalkoid membrane, where it is turned into NADPH and ATP
3)inside the thylakoid we have PS2 which absorbs 680 lambda of light
4) this radiation splits the H2O (within the plant) into H+ and O2 resulting in free electrons and protons as O2 leaves the plant (photolysis)
5) charged electrons then travel to the PQ while the H+ stays in the lumen of the thylakoid (as electrons travel to PQ protons are pumped into the thylakoid lumen from the stroma)
6) as the electron travels to B6F more protons are pumped into the lumen through the stroma
7) the electron goes to PC then PS1
8) PS1 can absorb 700 lambda of light and it again excites the electron
9) the electron continues to shuttle as it enters FD and then FNR
10) Lastly the electron reduces NADP to NADPH
11) Because of the exessive H+ in the thylakoid lumen the protons must leave the lumen because it is very acidic
12) Protons go through chemiosmosis where ADP is reduced to become ATP through the ATPase.


Calvin Cycle
The ATP and NADPH is used for the production of glucose in the Calvin Cycle

13) Rubisco combines  RuBP ( P-C-C-C-C-C-P) x3 with CO2 x3 to form (P-C-C-C-C-C-C-P) x3
14) it is then split to 3-phosphoglycerate (P-C-C-C) x6
15) ATP x6 is used to add a phosphate onto 3-phosphoglycerate to make it more stable to become 1,3-biphosphoglycerate (P-C-C-C-P) x6
16) 1,3-biphosphoglycerate is then oxidized as NADPH takes the P to become G3P
17) One of the G3P leaves the cycle 
18) the remaining (C-C-C-P) x5 goes through a series of steps to become the original RuBP (regeneration)
19) 3 ATP is oxidized to make G3P become RuBP (P-C-C-C-C-C-P) x3
20) Calvin cycle must run twice for 1 glucose to be made C6H12O6 <-- 6 carbons, G3P only has 3 carbons


Cyclic Electron Flow
-sometimes electrons use PS1 only
-electron is ejected from PS1 and passes FD --> B6F--> PC-->and back to PS1
-this pathway generates a proton gradient for synthesis of ATP but does not generate NADPH.



Sunday, November 7, 2010

Enzyme Lab

Procedure

1. Grind liver
2. Add  identical filter paper discs to the grinned liver
3. Pick out 35 identical filter paper discs (5 per run)
4. Dilute the acid and the base with different amounts of water to get different pH levels
5. Add 1 mL of NaOH to test tube #1, 2mL of NaOH to test tube #2, 3mL of NaOH to test tube #3
6. Add 1mL of HCl to test tube #4, 2mL to test tube #5, 3mL to test tube #6 
7. Add 4mL of water to test tube # 1 and 4, 3mL into test tube #2 and 5, and 2mL into test tube #3 and 6 
8. Thenn add 5 mL of hydrogen peroxide to each test tubes
9. Drop 5 filter paper discs in every Erlenmeyer flask for every run
10. Downward displacement
11. Watch for the rate of reactions ( bubbles) and look for amount of water displaced by oxygen

Results
TABLE:
Acidic Solution
Amount of HCl in(mL) added
1mL of HCl
2mL of HCl
3mL of HCl
5mL of HCl
pH level of the Solution
pH 5-7
pH 1-2
pH 1-2
pH 1
Colour of Litmus Paper
Yellow litmus
Orange/ red litmus
Red litmus
Red litmus
Amount of Water Displaced by Oxygen in (mL) and Qualitative Observation
Bubbles formed around filtrate paper, however no waters displaced
Bubbles formed around filtrate paper very quick. Approximately 5mL of water was displaced
Bubbles formed vigorously around filtrate paper. Approximately 6mL of water was displaced
Oxygen displaced as soon as filtrate paper touched solution and filtrate paper bubbled as well. Approximately 10mL of water was displaced.


Basic Solution
Amount of NaOH in (mL) added
1mL of NaOH
2mL of NaOH
3mL of NaOH
pH level of the Solution
pH 9
pH 9-11
pH 11
Colour of Litmus Paper
Blue/green litmus
Blue litmus
Dark blue litmus
Amount of Water Displaced by Oxygen in (mL) and Qualitative Observation
115mL of water displaced
11 mL of water displaced
2mL of water displaced


Saturday, October 30, 2010

Thermodynamics

There are three laws of thermodynamics. These laws focus on the inter-relation between heat, work and the internal energy of a system. In other words, it is the study of energy conversion in the form of heat . Thermodynamics focus on three major factors that affect energy conversion. These factors are: pressure, volume and temperature.


The 3 Laws

1)You cannot win

This law discusses the conservation of energy. Simply, it states that energy be created or destroyed. The sum of mass and energy is always conserved


2)You cannot break even

This law discusses the direction of the conservation. It states that energy cannot return to its original state because there is always an increase in entropy (disorder). According to physicist, Lord Kelvin, "usable energy in the universe is becoming less and less. Ultimately there would be no available energy left." Although quantity remains the same (First Law), the quality deteriorates over time. Accordingly because usable energy is used for productivity, growth or repair, it is converted into unusable energy. As usable energy decreases and unusable energy increases, "entropy" increases.



3) You cannot get out of the game

The third law refers to a state known as absolute zero. This is the lowest point on the Kelvin temperature scale. which corresponds to about -273.15° Celsius. This law reasons that no object or system can have a temperature of zero Kelvin.

Tuesday, October 19, 2010

Macromolecules

Carbohydrates (CH2O)n
-monomer: glucose
-functions: source of energy, building materials, cell surface makers for cell to cell identification and communication
-divided into three different categories: monosaccharides, polysaccharides, ogliosaccharides
- Monosaccharides contain an aldehyde or a ketone group and one or more hydroxyl groups ( arranged in straight chains while others are branched)
-ogliosaccharides are 2 or 3 simple sugars linked together
-An atom with five carbons is called pentose whereas a carbon with six atoms is referred to as hexose.
-polymers are formed through glycosidic linkages with condensation reactions (H20 is a product)
EXAMPLES: starch and glycogen


Deoxyribonucleic Acids
monomer:nucleotides
functions: inheritance genetics, protein synthesis
chains of units that each consist of a five-carbon sugar, phosphate and a nitrogenous base
polymers are formed through phosphodiester bonds (3 prime of the sugar)
Proteins
Monomer: short sequences of about 157 amino acids
Functions:structural building blocks, functional molecules, enzymes (biological catalysts)
Polymers are formed through peptide bonds 
broken down to c terminus and n terminus
c terminus has the carboxyl group while n terminus has the amino group
proteins have four different structures: primary secondary tertiary and quaternary
primary --> simple AA chain, 
secondary --> AA chains twirl into helix structure or sheaths, 
tertiary--> bending of the chain structure as a result of the attraction of AAs to one another
quaternary--> condensed pack chains of proteins with helix and sheaths
Lipids
hydrocarbons that generally do not dissolve in water but dissolve in non polar substances such as other lipids
Monomer: glycerol and fatty acid
Functions: storing energy, building membranes (its tail is hydrophobic so it binds with the tail of another phospholipid to create a membrane) and chemical signalling
3 types of lipids: , triglycerides, phospholipids, steroids
triglycerids is a glycerol bonded to three fatty acids through condensation reaction
phospholipids is  a glycerol bonded to two fatty acids and a phosphate group
steroids are four interconnecting carbon rings

polymers are created through ester bonds --> condensation reactions
saturated fats are all single bonded hydrogens (with no space available) NOT GOOD cant b decomposed unsaturated have double bond BETTER FAT



E.G. triglyceride, 




Tuesday, September 21, 2010

Replication

Initiation

-Helicase unwinds double stranded DNA into single strands
-at the same time DNA gyrase is working at the end of each replication fork to ease off the tension produced
-Single Stranded binding protein comes and blocks the single stranded DNA from forming hydrogen bonds AGAIN
-RNA primase comes and produces RNA primers 

Elongation
-RNA primers initiate DNA Polymerase 3 to elongate in the 5-->3 direction
 -At the replication fork there will be a leading (moving towards the replication fork) and a lagging strand (moving away from replication fork)
-leading strand will be continuously made, while the lagging strand will make it in fragments called okazaki fragments
- During the process of elongating the lagging strand, DNA Polymerase 3 must wait until the replication fork opens little by little until it can continue to elongate. Therefore it needs additional RNA primers to initiate this process.
-When each okazaki fragment is made, DNA Polymerase 1 will come and remove the RNA primers and replace it with the corresponding bases
-DNA ligase then joins the okazaki fragments by adding phosphodiester bonds (attaching 5 prime to 3 prime...Phosphate group + OH)

      
                                

Saturday, September 18, 2010

Famous Geneticists

The Dark Lady of DNA (1920-1958)
Rosalind Franklin's work in the structure of DNA has made a great contribution the the world of Genetics. Her expertise in X-ray diffraction helped her extract DNA fibers to study under humid conditions. This allowed her to discover the crucial key to the structure of DNA. However, she was not recognized for her accomplishments because of her hostile relationship with her assistant, Maurice Wilkins.  Without permission, Wilkins presented her discovery (photograph 51) to Watson and Crick who was also working on the DNA structure at the time. This picture helped Watson and Crick deduce the helical structure of DNA in 1953.  In 1962, Watson, Crick and Wilkins were rewarded The Nobel Prize for their discovery of the structure of DNA. Franklin died in 1958 at the age of 37.She was not recognized for her contributions or was she rewarded with The Nobel Prize because she had already passed away. It was unclear whether she would have been considered for the prize even if she was alive. It wasn't until twenty-five years later that Franklin's name was mentioned in Watson's journal, The Double Helix. Nevertheless, her contributions in the genetic world are well recognized today. 


Erwin Chargaff (1905-2002)
Erwin Chargaff was a biochemist who proposed two main rules known as Chargaff's Rule. His first rule showed that in natural DNA the ratio of adenine and thymine were equal and guanine and cytosine were equal. In human DNA, the four bases are present in these percentages: A=30.9% and T=29.4%; G=19.9% and C=19.8%.This hinted the complementary base pairing of DNA.In 1952, Chargaff shared his idea with Crick and Watson which helped them develop the helical structure of DNA.His second rule stated that composition of DNA varies between species, specifically in the relative amounts of A, G, T, and C bases.Similar to Franklin, Erwin Chargaff was also not recognized or given The Nobel Prize for his contribution towards the structure of DNA. 




Gregor Mendel (1822-1884)


Gregor Mendel, often crowned as the "Father of Genetics", derived the basic laws of heredity. His short monograph,Experiments with Plant Hybrids has become one of the most influential publications in the history of science. During his time, Mendel cross-bred pea plants in which he discovered his key insights. From his findings, he came up with the law of segregation (dominant and recessive genes) and the law of independent assortment (organism's individual traits are passed on independently of one another). Mendel's discoveries were not accepted during his time because they were far too advance. It wasn't until the 1900s when three botanists found his experimental data, that he became known.






Watson (1928) and Crick (1916-2004)


While working at Cambridge University, James D. Watson and Francis Crick proposed the DNA helical structure in 1953. They discovered that DNA was in the shape of a helix, about 2nm in diameter and had a complete helical turn every 3.4 nm.  Their proposal was later published into an article called, Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic.  Both Watson and Crick along with Wilkins were awarded with the Nobel Prize in Physiology or Medicine in the year 1962 for their discovery.  


Barbara McClintock (1902-1922)


Barbara McClintock made a significant contribution to the world of Genetics. She was interested in chromosome breakage as she observed the behaviors of chromosomes that lacked telomeres. In 1948, she had published a paper sharing her findings of the mutable loci. She discovered that the chromosome-breaking locus did "something" unknown. It moved from one chromosomal location to another. She called this transposition. McClintock discovered that transposition in genes are responsible for turning physical characteristics on or off. She developed theories to explain the repression or expression of genetic information from one generation of maize plants to the next. In 1983, she was rewarded with the Nobel prize.