Your Inner Fish Chapter 6

3 layers in embryos: 
Ectoderm: outer part of the body and nervous system
Endoderm: the inside layer, inner structures of the body
Mesoderm: our skeleton and our muscles.

What's really interesting is that in fact the same parts in these cells forms the same organs in every animal.

Dihybrid Cross

Once you understand monohybrid cross, dihybrid cross is basically the same thing. However, In contrast to a monohybrid cross, a dihybrid cross is a cross between F₁ offspring (first-generation offspring) of two individuals that differ in two traits of particular interest. For Dihybrid crossing, there are always 2 different traits Represented by different alphabets, for example let R be a dog with Red eyes and r be black eyes while Y be yellow skin and y be white skin. The question might be something like what are the genotype and phenotype ratios if you mate two heterozygous dogs together, which in this case would be RrYy X RrYy. And then basically you simply isolate the Rr X Rr and Yy X Yy and do the punett squares for both of them, then you multiply the results to get the ratios. Not rocket science.

Monohybrid Cross

Monohybrid cross is a really simple idea, simply take a sqaure and label all the sides with letters, which in most cases (A) means dominant trait while (a) refers to the recessive trait then you simply "multiply" them putting the terms together in the respective boxes of the sqaure and there you go, theres your genetic and phenotypic ratios.

Genotypic ratios: 1AA: 2Aa: 1aa
Phenotypic ratios: 3 dominants: 1 recessive

Unit 3 Test/ Lab

This test was pretty hard in my opinion, I forgot the RNA processing part in the free response and the multiple choice was definitely harder and more confusing than the previous tests.
As for the lab report, this is the first lab report that I actually completely did on a word document and it was a rather different yet rewarding experience since I got it done a lot faster than normal.

Operon System

Operon systems can either be inducible or repressible.

Repressible operon:

The repressor is originally inactive and the operon is on. Protein is being synthesized in repressive operons. Tryptophan is created in order for the repressor to be activate.  RNA polymerase reads DNA to create mRNA. Then RNA processing occurs and through transcription it eventually becomes a protein. Then the protein will become the co-repressor, thus activating the repressor to stop the system.

Inducible Operon:

The repressor is initially active and the system is off since RNA polymerase cannot access the gene getting blocked by the repressor. An inducer is needed to inactivate the repressor and allow the system to run again, in the pGLO lab that would be the arabinose. This would allow the RNA polymerase then go down the DNA and through protein synthesis produce the protein. Such protein is an enzyme that eats up the sugar. However, when all the sugar is gone, the repressor plugs back into its original position and activates again, turning the operon system off.