Is a macro molecule that stored genetic
information in all living organisms.
DNA vs RNA
The sugar on the ribose has a Hydrogen atom on carbon 3
Nulceosides vs Nucleotides
A nucleoside is a 5 carbon sugar with its nitrogenous bases
A nucleotide is a 5 carbon sugar with its nitrogenous bases and 3 phosphate groups
Describe nucleotides in DNA
Nucleotides in DNA contain deoxyribose, in RNA they contain ribose
Nucleoties are abreviated by letters
A Adeninde, C Cytosine, G Guanine, T Thymine, U Uracil
How is DNA organized?
Dna is organized accoring to the Watson-Crick model
- Backbone is composed of alternating sugar and phosphate groups and always reads 5' to 3'
- The two strands have polarity and are anti-parallel, they wind in a double helix
- A pairs with T, and U in RNA, G pairs with C always
Purined vs Pyridimines
Pure as Gold
Purines A and G have 2 Rings
Cut the Pie
Pyrimidines C, U & T 1 Ring
A + T via 2 hydrogen bonds
G + C via 3 Hydrogen bonds
What constitutes an aromatic molecule
Purines and pyrimides are biologial aromatic heterocyles.
Aromatic Compounds are
4n + 2pie electrons (where n is any integer HUCKELS RULE)
What is Chargaff's Rule?
Chargaff's Rule states that the purines and pyrimidines are equal in number in a DNA molecule,
and that becuase of base-pairing, the qty of adenine is equal to the qty of Thymine, ect.
B-DNA vs Z-DNA
Most DNA is B DNA, forming a right-handed helix.
Low concentrations of Z DNA, with zig-zag shape may be see with high GC contentor salt concentration
Chemicals that denature and reanneal DNA?
Denature; Healt, Alkaline pH, formaldehyde and Urea.
Removal of these condition may reanneal DNA
How many chromosomes in Eukaryotic/Human Cells?
DNA is organized in 46 chromosomes
What are histones and name the 5 histones
Histones are nucleoproteins
What are histones used for?
DNA is wound around histone proteins,
to form nucleosomes, wich may be stabalized by another histone proteins H1.
As a whole DNA and its associated histones make up chromatin in the nucleus.
Heterochromatin vs Euchromatin
Heterochromatin is dense, transcriptionally silent DNA that appears Dark under light microscopy.
Euchromatin is less dense, transcriptionally active DNA and appears light.
What are telomeres?
Telomeres are the ends of chromosomes.
The contain high GC (TTAGGG) content to prevent unraveling.
Durring DNA replication, telomeres are sligly shortened, although this can be (partially) reverswd by the enzyme telomerase.
What are centromeres?
Centromeres are at the middle of chromosomes, and hold sister chromatid together, untila they are separated at anaphase in mitosis.
Also have high GC content.
Steps and Proteins Involved in DNA Replication
Leading vs Lagging strand
Leading strand requiresonly one primer and can be synthesized continuously.
Lagging strand requires many primers and is synthesized in descrete sections called Okazaki Fragments.