Class 5: Genetics and Epigenetics Flashcards
What is by far the most complex molecule in our body?
Proteins (greek for ‘of first importance)
What are the three types of proteins?
- Structural
- Enzymes
- Cell Signaling
What do Structural Proteins do?
Helps to hold cells and tissue together
What do Enzyme Proteins do?
Catalyze chemical reactions and aid in metabolism
What do cell signaling proteins do?
Signal to other cells (ie NTs, Receptors for Hormones and Cytokines)
What are proteins made up of?
They are chains of amino acids (of which there are 20 types)
What determines the order of the amino acids for a particular protein? (the recipe)
DNA is the recipe for the protein
What are the two types of Necleobases of DNA?
Nucleobases are either Purines or Pyrimidines.
What are the two Purines compounds?
Adenine and Guanine
What are the two pyrimidine compounds?
Thymine and Cytosine
What are the two complementary strands of nucleobases?
A-T and G-C
What are genes organized into and how many nucleotides long is it?
Genes are organized into codons which are each 3 nucleotides long.
What are the 4 steps to use DNA to make proteins (gene expression)?
- DNA molecule partially unravels exposing structural gene for transcription
- A strand of messenger RNA copies one of the exposed DNA strands and brings it to the cytoplasm of the cell
- In the cytoplasm the mRNA attaches itself to a ribosome which moves along the strand translating each codon into the appropriate amino acid
- At the end the ribosome is instructed to release completed protein
What is an up-regulated gene?
More mRNA and protein which leads to a greater result in whatever that protein is supposed to be doing.
What is a down regulated gene?
Less mRNA and protein therefore less occurrence of whatever that protein is supposed to do.
Define Epigenetics
Changes in gene expression that happen as a function of environmental input
What are histones?
The proteins of which DNA is organized around clusters of.
What is chromatin?
The combination of DNA and histones
How do epigenetic changes occur?
When chromatin relaxes the DNA unfurls and allows for the gene to be transcribed. Epigenetic marks allow for chromatin to be more loose or more condensed.
Define Histone Acetylation
An epigenetic mark that relaxes the chromatin to allow for gene transcription
Define Histone Methylation
An epigenetic mark that tightens chromatin and decreases gene transcription
Increase DNA methylation of GR gene makes it easier or harder to shut down the stress response?
It makes it harder because the gene is less transcribed which means that there are fewer GRs to activate the shut down.
