Heredity and Variations

• Heredity also called as inheritance or biological inheritance


  is the passing on of traits from parents to their offspring; either through asexual reproduction or sexual reproduction
• Genes


  are passed from parents to offspring and contain the information needed to specify traits
• There are two types of cell in the body:

  • Somatic cell or body cell
  • Sex cell or gametes
• Somatic cell or body cell

  • make up the most of body tissues and organs
• Sex cell or gametes


  gametes are mainly cells for reproduction found in ovaries of female and testes of male
• Body cells contains 46 chromosomes, which come in pair and genetically identical.
• • The 23rd pair is called as the SEX CHROMOSOMES. Associated with the gender of the organism.
• • Female –XX chromosomes

  • Male – XY chromosomes
• Body cells are HAPLOID cells (n), meaning each cell has two pairs of chromosomes One pair of chromosomes is donated by the father and one pair of chromosomes from the mother (46 chromosomes).
• Sex cells are DIPLOID CELLS(2n), are cells contain one set of chromosomes (23 chromosomes). This have two copies of each chromosomes.
• Nucleic Acid


  are extremely complex molecules produced by living things, without this, enzymes and other proteins cannot be made.
• There are two classes of nucleic acid:

  • DNA or the Deoxyribonucleic acid
  • RNA or the Ribonucleic acid
• Genetics


  is the study of heredity and variations of different organisms
• Gregor Johann Mendel (1882-1884)


  is the “father of Genetics”.
• What plant did Mendel chose to study?

  Pea plants
• Genes


  are sections of DNA that determine certain traits or characteristics( the immune system, skin pigmentation, hormone production, and eye color)
• Alelle


  are different versions of the same gene
• Codon


  Is a sequence of DNA or RNA that corresponds to a specific amino acid.
• Amino acid


  Building block of protein
• Mutation


  is a change in amount or structure of DNA of an organism.
• Mutagens


  are substances or conditions that cause or increase the rate of mutation.
• What are the examples of mutagens?

  • X-RAYS
  • ULTRAVIOLET LIGHT
  • CHEMICALS
  • RADIATION
  • EXTREME TEMPERATURE
• What are the two major type of mutation?

  • Gene mutations
  • chromosomal mutations
• Chromosomal mutation 


  involves the change in the number or structure of chromosomes.
• Gene mutation


  Involves the change of genes, like alteration in DNA sequence
• Two types of gene mutation: Point mutation


  happen when there is a replacement (substitution)of one base pair from another
• Two types of gene mutation: Frameshift mutation


  occur when there is an insertion or deletion of the base pairs from the DNA structure.
• Any alteration of chromosome number or structure cause some GENETIC DISORDER.
• Nondisjuction


  Occurs when problems with the meiotic spindle cause errors in daughter cells.
• DNA


  it acts as the carrier of genetics information of almost all living things
• DNA


  It is double-stranded and has double helix structure
• Chargaff rules - Erwin Chargaff
• Purines = Pyrimides
• RNA


  is a single stranded structure
• RNA


  is a single-stranded structure and it function as a messenger
• Chess


  A game with two opposing sides, light colored and dark colored, briefly called White and Black
• How to Play Chess

  1. Begin with learning the chess pieces

  2. White always goes first
• Chess pieces


  • 1 King
  • 1 Queen
  • 2 Rooks (or Castles)
  • 2 Bishops
  • 2 Knights
  • 8 Pawns
• Pawn


  • Moves one square forward, but on its first move, it can move two squares forward
  • Captures diagonally one square forward
• Pawn's first move


  1. Can move forward one or two squares

  2. If already moved, can move forward just one square at a time

  3. Attacks (or captures) each square diagonally to the left or right