Genetics Notes How does this happen Heredity The

Genetics Notes

How does this happen?

Heredity • The passage of genetic instructions from one generation to the next generation • Traits are passed from parents to offspring through genetic material

Genetic Material: In the Nucleus • DNA • Genes • Chromosomes • Genetic material is located in the nucleus of each cell!!!

DNA • Deoxyribonucleic Acid • DNA has a double helix shape (twisted ladder) • DNA is divided into segments called genes

Genes and Chromosomes • Gene: A segment of DNA that codes for a specific trait • Each of your cells has 46 strands of DNA inside (in the nucleus) • Each DNA strand is wound up tightly around itself and is called a chromosome Replicated Chromosome

Karyotype: picture of all of the chromosomes in the nucleus of a cell

DNA, Genes, and Chromosomes

Traits • Inherited traits: physical characteristics that are passed on from parent to child through DNA • An organism can only pass its DNA to its children. . . nothing else! • This means that an organism can only pass on traits that they are born with! • Examples: eye color, height, gender, ear lobe shape, skin color, baldness, etc.

Traits • Acquired traits: changes to physical characteristics that occur after conception/birth due to the environment • Examples: broken bones, tattoos, haircuts, weight, bacterial/viral diseases, good grades, athletic achievements, etc. • Acquired characteristics CANNOT be passed on from parents to offspring!

Environmental Influence • Inherited traits are sometimes influenced or changed by the environment (these changes are NOT inherited/passed on) • Example: height is affected by diet • Example: muscle strength is affect by exercise

Inherited Traits and Genetic Material • Inherited traits are governed in the genetic material found in genes, within chromosomes in the nucleus