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Organization of DNA from smallest to largest
How many genes encoded by DNA
How many genes in mitochondria
All genes in mitochondria are essential for
Mitochondrial genes origin
DNA building block made of how many bases?
Four building block bases of DNA
- 2 purines
- 2 pyrimidines
- Also backbone of deoxiribose (5 carbon sugar)
Guanine bonds to
Both DNA and RNA
Guanine and adenine
Used for DNA/ Used for RNA
Thymine and cytosine/Uracil and Cytosine
Phosphate use in DNA
Chains together carbon (nucleosides become nucleotides)
Phosphate/sugar backbone is called
Purines found in the body but NOT in DNA
Methylization of xanthine creates
Caffein naturally in the body
Difference between ribose and deoxyribose (RNA and DNA)
One oxygen molecule (DNA is missing the oxygen)
Double stranded DNA+small basic proteins (histones) + small amount of nonhistone proteins
Arginine and lysine-rich basic proteins
Histones (part of composition of chromatin complex)
Positive charge on AA helps bind histones to
Negative charge on DNA sugar phosphate
Core of 8 histones with DNA wrapped around
Nucleosomes wind up to form
Chromatin strand winds tight to form
Chromasomes during mitosis or miosis
Number of chromosome copies in a cell
Most cells in the body are
Diploid, exception being germ cells (sperm and egg, haploid cells)
Diploid cells have copies from
Mom and dad (one of each)
Haploid gene has how many base pairs
Haploid genome has how many chromosomes?
23 (22 somatic, 1 sex)
Haploid genome has enough DNA to code for
1.5 million genes, really only codes for 21,000 genes
DNA that doesn't code for any of our 21,000 genes is
"Junk." Doesn't appear to code for anything to be produced. May be important in regulation of production.
Total number of protien species produced by the body is called
Many protein species are regulated by
Small non-coding RNA that control translation and post-translational changes
Micro RNA (miRNA)
Deregulation of miRNA can lead to
Diabetes, cancer, schizophrenia, depresion, etc.
Two parts of eukaryotic DNA
- Unique DNA sequences (genes)
- Repeat sequences ("junk")
Trinucleotide (microsatellite) repeats and disease - repeat sequences repeated too many times cause
Disease! e.g. - Huntingtons, Kennedy, Fragile X, etc.
Dispersed repetitive sequences are found where?
Found mingled around coding genes (unique DNA sequences)
Non-specific DNA "clippers," long interspersed elements - 7000 bp
Reverse transcriptase does what?
Codes RNA, turns it back into cDNA
Lines v sines
- Lines - long interspersed elements (7000 bp)
- Sines - Short interspersed elements (90-500 bp)
- bp=base pairs
- Both are dispersed repetitive sequences
Where are genes located?
Located in chromosomes and in mitochondria
Genes contain two regions -
- Promoter region
- Control region
How much of a gene sequence is required for generating a product?
The entire sequence is required for the product to be produced
What is epigenetics?
Stable changes to a gene structure, without changing the DNA sequence
If there is no change in gene structure, how do epigenetics work?
Changes in gene expression
Epigenetics are controlled by
- **Methylation of cytosines
- Tissue-specific chromatin alterations
What do DNA strands wrap around for storage?
Proteins called Histones (spools for DNA to wrap around)
Acetylation of lysine does what to DNA-histone interaction?
Weakens the interaction, easier for transcription factors to access the DNA strand
Histone deacetylase does what to DNA-histone interaction?
Tightens it, makes it more difficult for transcription factors to access DNA strand
Two ways to describe compaction of DNA in chromatin
- Euchromatin - loosely packed, transcriptionally active
- Heterochromatin - densely packed regions, genetcally inactive
Unhealthy epigenetic alterations
- Excess oxidation and free radicals
- Excess alcohol
- Pychological stress (hormones)
- Chronic inflammation
Healthy epigenetic alterations
- Polyunsaturated fats
- Fruits and veggies (polyphenols)
- Folate and vitamin B12
Epigenetic changes in fetus: Depression causes
- Exposure of hypothalmlic-pituitary adrenal axis with higher levels of corticotrophin releasing hormone
- Babies born with less developed prefrontal cortex
Epigenetic changes in fetus:diabetes causes
- Hyperinsulinemia in the fetus, increase oxygen consumption and metabolism
- Causes chronic intraunterine tissue hypoxia