Inheritance+ Variation (Chp.10)

• Genetics is the study of inheritance/heredity
• Acquired characteristics: are not inherited they are learned through life e.g reading
• Inherited characteristics: are passed from parent to offspring through genes e.g eye colour
• The environment can influence how genes work(phenotype=genotype+environment)
• Phenotype: the traits that can be seen in the organism e.g brown eyes
• Genotype: the genes that the organism possesses 2 genes for brown eyes
• Dominant: a gene that prevents another gene from working e.g gene for brown eyes prevents gene for blue eyes from working
• Recessive: a gene that is prevented from being expressed e.g blue eyes is prevented from working by the brown eye gene
• Species is a group of organisms that can breed and produce fertile offspring
• Variation is the way members of the same species differ from one another
• Asexual reproduction is when there is only one parent (the offspring inherits all of their genes) e.g strawberry plants can reproduce by runners
• Sexual reproduction: 2 parents(the offspring get a copy of every gene from each parent. They get 2 copies) e.g strawberries use flowers to make seeds
• Inherited variation

  Chromosomes are threads of DNA and protein in the nucleus, 46 in human cells
• Genes are specific patterns of DNA(deoxyribonucleic acid) that code for a protein(30,00 in human)
• Genetic code takes a form of a pattern/sequence of bases

  • A pairs with T
  • G pairs with C
• Each cell has 2 copies of each gene (one from each parent)

  Dominant genes are always used, recessive ones aren't always used
• Pedigrees shows us how characteristics are passed down in family trees
• Females - circles

  Males - squares

  If you have the condition being examined you are "coloured in"