Molecular Basis of Inheritance Flashcards
What is the flow of the Central Dogma
DNA —> (transcription)—> RNA—> (translation)—-> Protein synthesis
What are Chargaffs Rules
the nitrogenous base composition varies between species
the amount of A=T
and the amount of G=C
Where do new nucleotides add on
3’ OH
What is a chromosome
A DNA molecule packed with proteins
What is the composition of bacterial chromosomes
DNA is double stranded
Bacteria have a single, circular chromosome
Bacterial chromosomes have a small amount of protein
DNA is supercoiled and found in a region of the cell called the nucleoid
What is the composition of Eukaryote chromosomes
DNA is double stranded
Eukaryotes have multiple, linear chromosomes
Eukaryotic chromosomes have a large amount of protein
Chromatin is the complex of DNA and protein found in the nucleus
What are histones
they are positively charged proteins that are responsible for the first level of DNA packing in chromatin
DNA is negatively charged so they bind to it
What is Euchromatin
it is loosely packed chromatin that is accessible for gene expression
most chromatin is loosely packed in the nucleus but condenses prior to cell division
What is Heterochromatin
It is highly condensed chromatin that is inaccessible to gene expression machinery
what are nucleosomes
-They are a complex of DNA and histone proteins
-Promote and guide coiling of DNA
-DNA duplex coiled around 8 histone proteins every 200 nucleoid
strings of histone “beads” linked by DNA
How does differences in cells arise?
differential gene expression
What is histone acetylation
acetyl groups are attached to positively charged lysines in histone tails —> this loosens chromatin structure which facilitates transcription
Which nitrogeneous bases have triple H-bonds
Cytosine and Guanine
Which bases are purines
A,G
Which bases are pyrimidines
C,T,U
