3.15 Genes

Understand that a gene is a section of a molecule of DNA

1. DNA is made up of genes. DNA is the complex chemical that carries genetic information. DNA is contained in chromosomes, which are found in the nucleus of most cells. The gene is the unit of inheritance and different forms of the same gene are called alleles.
2. The genes carry information which form the characteristics  of the organism. Eg: blood group or the color of a petal for flowers.
3. The information is passed to the cytoplasm and it is there that the genetic info is transformed into a protein. The protein controls the production of the characteristic.
Double Helix shape (characteristic)

3.14 Chromosomes

Recall that the nucleus of a cell contains chromosomes on which genes are located.

1. The nucleus of a cell contains chromosomes, which carry genetic information in a long molecule called DNA. (the double helix) Different Organisms have different amounts of Chromosomes. (Humans have 46)

2. Genes are regions of DNA that carry the code to control a particular cell activity or the production of a particular protein.

3. Chromosomes work in pairs. Known as homologous pairs. Homologous pairs are paired up by size/shape.  One of the pair you inherit from your father, the other from your mother.

Homologous chromosomes pair during meiosis - the cell division that occurs as part of the creation of gametes (sex cells).
4. The same position/loci on the pair has the same gene (separate versions for one characteristic)


question: I don't understand the role of the locus.