Genetics

• Chromosome is a structure in the cell nucleus that contains genetic instructions in the form of DNA
• How many pairs do humans have?

  23 pairs
• What do chromosomes contain

  Genetic instructions for cell structure, function and growth
• DNA is the molecule that carries genetic information in chromosomes
• Where is genetic material located in cells?

  In chromosomes within the nucleus
• Hyperplasia


  Excessive and uncontrolled cell division
• 22 pairs of autosomes + 1 pair of sex chromosomes
• What are the effects of damage to chromosomes?

  Mutation
• Gene is a unit of heredity within DNA that codes for a specific protein
• How many copies of each gene does a person inherit?

  2, one from each parent
• Where are the genes located

  On chromosomes
• What happens if the DNA sequence of a gene is altered?

  Changes in protein synthesis may occur
• What makes someone a carrier of a genetic condition?

  one normal

  one abnormal copy of a gene
• Why dont carriers typically show symptoms

  The normal copy is usually dominant over the abnormal copy
• What are the three possible genotypes for a gene with dominant and recessive alleles

  Homozygous Dominant

  Homozygous recessive

  heterozygous
• How many phenotypes are possible with a simple dominant//recessive gene

  Two (Normal and affected)
• Which genotypes result in a normal phenotype

  BB and Bb
• What does it mean to be homozygous for a gene

  Having two identical copies of the gene
• Example of Homzygous genotypes

  BB or bb
• What does it mean to be heterozygous for a gene?

  Having two different alleles for a particular gene.
• Sex linked disorders are inherited conditions caused by genes located on sex chromosomes, particularly the X Chromosomes
• Why are males more likely to show Xlinked disorders?

  Males have one X chromosomes, no back up copy