Genetics Flashcards
Mendelian Genetics
Gregor Mendel
Laws that describe family patterns of inheritance of single genes.
Cytogenetics
Uses techniques of cytology and microscopy to study chromosomes and their relationships to hereditary traits.
Molecular Genetics
Studying structure and function of DNA at the molecular level.
How genes control cellular functions, development, and disease.
Genomic Medicine
Application of knowledge of the human genome for prediction, diagnosis, and treatment of genetic diseases.
DNA
Each cell:
46 human chromosomes
2m of DNA
3 billion DNA subunits (the bases: A, T, C, G)
20,000-25,000 genes code for proteins that perform all life functions.
DNA Molecular Structure
A kind threadlike molecule with a uniform diameter but varied.
2 meters in length.
A polymer that encodes hereditary information; 4 different repeating monomers(nucleotides) make up DNA polymer.
Each nucleotide consists of one sugar(deoxyribose), one phosphate group, one nitrogenous base:either pyrimidine (single carbon-nitrogen ring) or purine (double ring); A, T, C, G
Nitrogen bases
Purines:double ring(adenine,guanine)
Pyrimidines:single ring(cytosine,thymine)
DNA Structure
Molecular shape is a double helix(staircase)
Each side piece is a backbone composed of phosphate groups alternating with the sugar deoxyribose.
Steplike connections between backbones are pairs of nitrogen bases.
Complimentary Base Pairing
Nitrogenous bases united by hydrogen Bonds. Purine on one backbone always base pairs with a pyrimidine on the other.
A-T two hydrogen bonds
C-G three hydrogen bonds
Law of Complimentary Base Pairing
One strand determines base sequence of other.
DNA Function
Genes-genetic instructions for synthesis of proteins.
Gene-segment of DNA that tells how to make a certain protein(codes for protein)
Genome-all the genes of one person
-humans have estimated 25,000 to 35,000 genes.
-2% of total DNA
-Other 98% in noncoding DNA; plays role in chromosomes structure, very important regulation of gene activity, same has no function at all-junk DNA.
Chromatin
In the nucleus, DNA is complexed with protein to form threadlike Chromatin:
- nondividing state and the DNA molecules are highly compacted.
- coiled around core histone proteins to form nucleosides.
- zig-zagged, looped and coiled into itself.
- functions to package DNA into small volumes to fit the cell.
- chromatin condense to chromosomes during mitosis(higher order DNA Organization)
Flow of Genetic Information
Replication(DNA-DNA)
Transcription(DNA-RNA)
-in nucleus DNA is transcribed or copied into a messenger RNA(mRNA) molecule
Translation(RNA-Proteins)
-in the cytoplasm, the mRNA code is translated into amino acids.
Production of Amino Acids
- DNA double helix
- seven base triplets from DNA; 3 base pairs in gene code for one amino acid.
- the corresponding codons of mRNA transcribed from the DNA triplets
- the anticodons of tRNA that bind to the mRNA codons
- the amino acids are carried by those 6 tRNA molecules
- the amino acids linked into a peptide
Human Genome
Humans have 46 chromosomes
-23 from mom and 23 from from dad
Genome-all the DNA in one 23-chromosomes set
An organisms complete set of genetic instructions
-3.1 billion nucleotide pairs in human genome
Every cell in our body has the same DNA
Gene Regulation
What makes one cell type different from another.
Genes are turned on and off from day to day
Their products are needed or not
Many genes are permanently turned off in any given cell
Gene
Body had 20,000 genes.
Not a separate gene for every protein.
A gene is a segment of DNA that tells the cell how to make a certain protein (codes for protein)
Amino acid sequence is determined by the nucleotide sequence in DNA.
A Information containing segment of DNA that codes for the production of a molecule of RNA that plays a role in synthesizing one or more products.
The Human Genome Project(1990-2003)
International effort to decipher the blueprint of a human being.
Hundreds of scientists at 20 sequencing centers in China , France, Germany, Great Britain, Japan, and United States collaborated to discover the complete set of human genes.