10.1 The Concept of a Gene as a Unit of Inheritance
In 1865 Mendels crossbred pea plant experiment revealed:
1) Plant characteristics were governed by units of inheritance called genes. Alternate forms of a gene are called
alleles which can be dominant
11.4 Synthesis and Processing of Messenger RNAs
If eukaryotic cells are incubated for short time in [ 3H] uridine or [32P]phosphate and immediately killed,
most of the radioactivity is incorporated into large group of RNA molecules found in the nucleus
11.1 The Concept of a Gene as a Unit of Inheritance
Beadle and Tatum irradiated spores to induce mutations. They allowed them to grow in colonies in tubes
containing supplemented medium. Individual spores produced by the colonies were tested for their a
10.5 The Stability of the Genome
Duplication and Modification of DNA Sequences
Unequal crossing over occurs when a pair of homologous chromosomes comes together during meiosis in such a way that
they are not perfectly aligned. Because of misalignment, g
Steps for assembly of splicing machinery:
1) U1 attaches to the 5 end and forms complimentary pairing with the 5 splice site.
2) U2 binds causing a specific adenosine residue to bulge out of the helix. This becomes the branch point of
the lariat. U2 is
Identifying the Codons
Nirenberg and Matthaei first synthesized poly U and added it to test tube containing bacterial extract with
all 20 amino acids and necessary materials for protein synthesis, the system assembled a polypeptide which
was found to be
12.4 Transcriptional Level Control
A DNA microarray was used to compare the populations of mRNA present in yeast cells when grown in
glucose rich medium and when grown in ethanol rich (without glucose) medium.
Preparation of yeast microarray:
1) DNA f
Formation of heterochromatin:
1) RNA is transcribed from both strands of repeated DNA sequences.
2) The RNA forms double stranded molecules.
3) Endonuclease Dicer and other components of the RNAi machinery form a single stranded RNA guide
and an associa
Steps to import proteins into nucleus:
1) Protein with NLS signal binds to heterodimeric receptor (importin /)
2) Transport receptor escorts protein to surface of nucleus where it docks with cytoplasmic filaments.
3) Receptor cargo complex moves through
Step 2: Peptide Bond Formation
Peptide bond formation is accomplished as amine nitrogen of aa-tRNA in A site carries out nucleophilic attack on carbonyl
carbon of amino acid bound to tRNA on P site, displacing the P site tRNA. This leaves the tRNA bound