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GENES • 1865 - Gregor Mendel studied inheritance patterns using pea plants and observed traits were inherited as separate units. • These traits are now known as genes! • He founded Modern Genetics- the function and behavior of genes. • Genes are bits of biochemical information carried through generations by molecules called DNA.
DNA • DEOXYRIBONUCLEIC ACID • One of several types of nucleic acid found in cells. • Double-stranded form usually forms a double helix. • Genes exist as segments along the DNA molecule. • The DNA that carries the genetic information in cells is packaged in one or more larger molecules called chromosomes.
CHROMOSOMES • Chromosomes are long, continuous pieces of DNA that contain many genes.
• Genes are blueprints that direct the synthesis of proteins that carry out the life-supporting activities of the cell. • All humans share the same set of genes, but can inherit different forms of a given gene from their parents, making each individual unique, ( except for identical twins whose genes are exactly the same).
GENETICISTS • Scientists who study genes and their variations.
Genetic Engineering • Technique used by scientists to manipulate genes. • Has produced many advances in science but with that comes ethical issues!
Gene Mapping and The Human Genome Project • Genetic mapping charts the position of known genes relative to each other. • The Human Genome Project was completed in 2003. • The project produced detailed maps that identify the chromosomal locations of the estimated 20 -25, 000 human genes. • The purpose of this project was to examine how gene activity can cause disease.
Genotype and Phenotype • Genotype-combination of genes that code for a trait. • Phenotype- the physical manifestation of a trait.
Alleles • When one gene is dominant over its alternate gene occupying its position on a chromosome.
DIFFERENT COMBINATIONS • Incomplete Dominance- the inheritance of a dominant and recessive allele results in a blending of traits to produce intermediate characteristics. • Quantitative Inheritance- each pair of genes has only a slight effect on the trait while the cumulative effect of all the genes determines the physical characteristics of the trait.
• Multiple Alleles- certain traits are controlled by multiple alleles that have complex rules of dominance. • Gene Linkage- when genes affecting the phenotypes are found on different chromosomes. • Crossing over- when a chromosome pair may intertwine and exchange sections of chromosome, then break apart to form two chromosomes with a new combination of genes that differs form the combination supplied by the parents.
Mitosis and Meiosis • Mitosis is the process, in the cell cycle, by which the chromosomes in the cell nucleus are separated into two identical sets of chromosomes, each in its own nucleus. • Meiosis-is a special type of cell division necessary for sexual reproduction which occurs or has occurred in all eukaryotes, including animals, plants and fungi, including both multicelled and single-celled organisms. The number of sets of chromosomes in the cell undergoing meiosis is reduced to half the original number
RECOMBINATION/ SEX-LINKED TRAITS • R- How often genes on a chromosome measures the distance between them. • S- One pair of chromosomes in which the partners noticeably differ form each other. • Sex chromosomes determine the difference between males and females. • Genes located on sex chromosomes display different patterns of inheritance than genes located on other chromosomes.
SL Traits cont'd. • In females, the sex chromosome consists of two X chromosomes, while males have a X and a shorter Y, with many fewer genes.
GENETIC CODES/ NUCLEOTIDES • GC- Biochemical instructions within most genes that specify the chemical structure of a particular protein. • N- Chains of building blocks formed by DNA molecules. • They consist of a sugar molecule, (deoxyribose), a phosphate group and one of four bases: Adeneine(A), Thymine(T), Cytosine(C), and Guanine (G). • The order of the bases in a DNA molecule, (genetic code), determines the amino acid sequence of a protein.
TRANSCRIPTION/RNA/MESSENGER RNA • T- DNA goes through a process to an intermediary molecule (RNA). It involves the production of a special kind of RNA, Messenger RNA, where the DNA molecule unwinds and is used to create messenger RNA.
TRANSLATION • Once transcription is complete, and the genetic code has been copied onto m. RNA, the genetic code must be converted into the language of proteins. The information coded in the four bases in m. RNA must be translated into instructions encoded by the 20 amino acids used in the formation of proteins. • Translation takes place in cellular organelles called ribosomes.
Mutations/ Gene Regulation • M- Mistakes that occur during DNA replication and protein synthesis. • Some mutations occur spontaneously, others are caused by environmental exposures. • GR- The process enabling information to be copied from genes and used to synthesize proteins must be regulated for the cell to survive.
Genetic Engineering/ Recombinant DNA Gene Therapy/ Proteonomics • GE- The alteration of genes in an organism. • RDNA-one or more genes of an organism are introduced into a second organism. • GT- The insertion of one or more genes into an individual to treat disease, especially inherited(genetic) diseases. • P- A new science in which researchers are identifying the structure and function of all proteins in the human body.
Gametes/ Eugenics • Gametes are the egg and sperm cells involved in reproduction. • Eugenics is the study of hereditary involvement of the human race by selective breeding.