T1M4 Flashcards
Where is DNA in prokaryotic cells?
the majority of DNA is contained in the nucleoid
Plasmids
small circular DNA molecules, carry one or two genes (EG antibiotic resistance), replicate independently of the core genome/transfer
Chromosome
organization of a double-stranded DNA molecule in its association with proteins and RNAs
Shape and size of chromosomes in eukaryotic and prokaryotic cells
eukaryotic cells have large linear chromosomes and prokaryotic cells have smaller circular chromosomes
Supercoiling
preserves the double helix structure and
compacts the DNA into a small space.
Who recreated Fred Neufeld 1920’s experiment
Frederick Griffith (1928), killed virulent bacteria -
Cells of the benign strain had acquired information, or the ability to be virulent, from the dead cells.
Transformation
a change in cell behaviour resulting from the incorporation of hereditary material from outside of the cell.
1944, Oswald Avery and colleagues experimented to determine
Which macromolecule in the bacterial cell was holding all that important information that could cause transformation. Which molecule was carrying the hereditary information?
A single nucleotide 3 components
a phosphate group, a 5-carbon deoxyribose sugar, and a nitrogenous base.
Chargaffs rule
DNA from any cell of all organisms should have a 1:1 ratio of pyrimidine and purine bases
Base pair rule
amount of guanine is equal to cytosine and the amount of adenine is equal to thymine
Pyrimidines
C and T - aromatic heterocyclic molecules that
have a single ring
Purines
A and G - consist of two rings: a pyrimidine ring
fused to an imidazole ring
two nucleotides are bonded together by a…
Phosphodiester bond (condensation reaction releases a water molecule and forms a covalent bond)
Phosphoribose backbone
the phosphate group on the 5’ carbon of the deoxyribose forms a bond with the hydroxyl group on the 3’ carbon on the next deoxyribose
Double helix structure (watson and crick)
two strands run anti-parallel to each other, with the bases facing inwards to give a diameter of
2.0 nm. The helix has a major groove and a
minor groove, with one turn of the helix occurring every 10 nucleotides.
How are RNAs synthesized?
transcription of a sequence of DNA using an
enzyme complex called RNA polymerase
Types of RNA (4)
messenger, ribosomal, transfer, enzymes
Nitrogenous bases RNA VS DNA
the pyrimidine, uracil, replaces thymine (uracil has a hydrogen where thymine has a methyl group)
