C4 versus CAM pathway

What is C4 Plants?
a alternative pathway for C3 plants

What is CAM plants?

Comparison and Contrast between C4 plants and CAM

Results from Catalase Lab

Our group was tasked to determine the rate of reaction on different amount of catalyst (different number of chips used).

	Chips used	Amount of time consumed (Second)	Oxygen produced (mL)
Trial 1	1	35	25
Trial 2	3	25	25
Trial 3	5	17	25
Trial 4	7	10	25
Trial 5	9	6	25

Importance of Entropy

Three Laws of Thermodynamics

• Conservation of mass - energy                   Energy can neither be created or destroyed
• Law of Entropy                                         All spontaneous events act to increase total entropy
• Absolute Zero                                           Absolute zero is removal of all thermal molecular motion

The second law of thermodynamics states that in general the total entropy of any system will not decrease other than by increasing the entropy of some other system. Hence, in a system isolated from its environment, the entropy of that system will tend not to decrease. It follows that heat will not flow from a colder body to a hotter body without the application of work (the imposition of order) to the colder body.

PCR versus Vector Cloning

Vector Cloning Process:

• Bacteria are able to express foreign genes inserted into plasmids (small, circular, double-stranded DNA molecules lacking a protein coat that naturally exist in the cytoplasm of many strains of bacteria)
• The bacterial cell benefits from the presence of plasmids. Plasmids often carry genes that express protein able to confer antibiotic resistance. They also protect bacteria by carrying genes for resistance to toxic heavy metals, such as mercury, lead, or cadmium. In addition, some bacteria carry plasmids possessing genes that enable the bacteria to break down herbicides, certain industrial chemicals, or the components of petroleum. The relationship between bacteria and plasminds is endosymbiotic.
• If a bacterium readily takes up foreign DNA, it is described as a competent cell. Most bacteria are not naturally competent but can be chemically inducedinthe laboratory to become so with the aid of calcium chloride at 0 degree. Nowadays, scientists also use electric shock to introduce the plasmids into the host cell.

PCR (polymerase chain reaction) Process:

• DNA primers replace RNA primers and are used in PCR. Becasuse they are easily synthesized in the laboratory.
• Taq polymerase, a DNA polymerase is isolated from Thermus aquaticus, a bacterium that lives in hot spring is used as elongating enzyme in PCR.
• By the third cycle, the number of copies of the targeted strands begins to increase expontentially.

PCR versus Vector Cloning:

• Vector Cloning is relatively cheaper than PCR
• PCR requires less time to replicate DNA
• Vector Cloning can be used to produce protein but PCR can not
• PCR only needs a small amount of DNA to work however Vector Cloning needs specific, and compeletly target DNA.
• Vector Cloning needs specific restriction enzymes however PCR uses DNA polymerase and unique Taq polymerase.
• Vector Cloning can be used in treating medical disorder and PCR can be used in forensic criminal investigaitions.

DNA replication enzymes

Important enzymes of DNA replication

Stage	Enzyme	Function
Initiation	DNA Helicase SS binding protein DNA gyrase primase	Unwinds the DNA Protects the DNA single strand from binding by hydrogen bonds Relieves tensions Adds RNA primers to initiate elongation
Elongation	DNA polymerase Ⅲ	DNA polymerase Ⅲ adds complementary nucleotides in the 5’ to 3’ direction.
Termination	DNA polymerase Ⅰ DNA ligase	Removes RNA primers by deoxyribonucleotides. Joins the Okazaki fragments together creating phosphodiester bond.

Chromosome

Chromatid

1-       eukaryotic chromosome

2-       Centromere - the point where the two chromatids touch

3-       Short arm

4-       Long arm

Chromatin: is the combination of DNA and other proteins that make up the contents of the nucleus.

Centriole:

Centrosome: are composed of two orthogonally arranged centrioles surrounded by an amorphous mass of protein termed the pericentriolar material.

 

The history of finding DNA

First Part: The way DNA identified as hereditary material
                1. Friedrich Misescher, a Swiss biochemist, first investigated nuclein, now known as NDA.
                2. Joachim hammerling, a Danish biologist, conducted a series experiments using Acetabularia, a one-celled alga, to raise a hypothesis that the hereditary imformation is in the nucleus.
                3. In 1952, Afred Hershey and Martha Chase conducted experiments using a virus(T2) to prove that DNA was the hereditary material.

Second Part: The finding of DNA structure
                1. In 1949, Erwin Chargaff found that the proportion of adenine(A) is equal to that of thymine(T), and the proportion of guanine(G) is equal to that of cytosine(C). Also, total amount of purines equals the total amount of pyrimidines. (This discover helps solve the mystery about hte stucture of DNA)
                2. James Watson and Francis Crick built their famous model of the double-helix structure of DNA in 1953. (information provide by Maurice Wikins and Rosanlind Franklin)
                3. Rosanlind Franklin's x-ray crstallography technic sucessfully produced a clear x-ray diffraction pattern that suggested that DNA is helical in nature.

New Terms:
1. Nucleotides: molecules that consist of a five-carbon sugar(deoxyribose or ribose) with a nitrogenous base attached to 1' carbon and a phosphate group attached to 5' carbon.

Properties of DNA
1. antiparallel(parallel but running in opposite directions)
2. complementary base pairing
3. diameter of DNA is constant at 2nm