INHERITANCE

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INHERITANCE
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Interest Approach

• Pea plants
• Different colored flowers
• What was different about each plant??

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History of Genetics

• 1670s
• Scientists believed that each sperm contained a
  little man that would develop into a human
• Then mother only served as an incubator

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History of Genetics cont.

• 1750s
• Blending of Inheritance Theory
• Example
• Black animal mated to a white animal would
  produce a gray animal

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History of Genetics cont.

• 1850s
• Gregor Mendel
• Austrian monk and worked in the monastery garden
  mating pea plants
• Determined that characteristic were inherited by
  discrete factors that would eventually become
  know as genes

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Gregor Mendel

• Discovered many principles
• Principle of segregation
• Principle of independent assortment

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Principle of Segregation

• Every individual carries pairs of factors for
  each trait and that the members of the genes
  segregate at random during the formation of
  gametes
• Since segregation is random, predictable ratios
  of traits are found in the offspring
• During segregation, chromosomes go from a pair
  (2n or diploid) to singles (1n or haploid). Good
  way to remember

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• Hap a diploid is 1n

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Principle of Independent Assortment

• Members of each pair of genes are distributed
  independently when the gametes are formed and are
  unaffected by other gene pairs on other
  chromosomes
• When pairs of genes on different chromosomes
  separate, they have an equal chance or
  probability of going to an individual gamete
• No predetermined order for the dividing pairs
• EVERY GENE FOR ITSELF

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Chromosomes

• Located in the nucleus of the cell and contain
  all of the genetic material in the cell
• Arranged in pairs
• Made up of a substance called DNA

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Two Types of Chromosomes

• Haploid
• Half the diploid or somatic (non-sex cell or
  gamete) number of chromosomes (n or 1n)

• Diploid
• Number of chromosomes found in the somatic or
  body cells (2n).
• Twice the number of chromosomes found in the
  gametes

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Chromosomes in Animals

• 1n
• 30
• 27
• 30
• 40
• 30
• 23

• Cattle
• Sheep
• Goat
• Swine
• Horse
• Human

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DNA

• Deoxyribonucleic Acid

• Three Components
• Deoxyribose sugar
• Phosphate
• Four nitrogenous bases
• Adenine (A)
• Thymine (T)
• Guanine (G)
• Cytosine (C)

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Nucleotides

• Combination of the deoxyribose, phosphate and one
  of the four bases
• Nucleotides bond together to form one strand of
  the DNA molecule
• Two of the strands wind around each other in a
  double helix to form the DNA molecule

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In the two pairs of DNA

• C is always paired with G
• AND
• A is always paired with T

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(No Transcript)
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The Gene

• Genes are points of activity found in each
  chromosome that govern the way in which traits
  develop. Genes are specific areas on each
  chromosome and are made up of DNA

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Protein Synthesis

• RNA (ribonucleic acid) is a group of molecules in
  charge of reading and translating the genetic
  code for the formation of new proteins
• RNA uses the DNA as a template to read the code
  in order to produce the right protein with the
  correct order and number of amino acids.

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Three Types of RNA

• Transfer RNA (t RNA)
• Plays a key role in protein synthesis (building).
  Each tRNA molecule can combine with one amino
  acid and can transport the a. a. to the new
  protein building site in the cytoplasm of the cell

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Three Types of RNA cont.

• Ribosomal RNA (rRNA)
• Also plays a key role in protein synthesis. It
  helps control the connecting of the parts of the
  protein (the amino acids) together.

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Three Types of RNA cont.

• Messenger RNA (mRNA)
• Helps complete the building of the protein
• Physically sequencing the amino acids that were
  carried to the building site by the tRNA and
  chemically connected by the rRNA
• The mRNA directs the sequence based on the order
  it obtains from the DNA molecule

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In RNA Translation. . .
C is paired with G T is paired with A A is
paired with U
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Activity Building DNA

• Materials Needed
• Several of each
• Four different colored gumdrops or other material
  that a toothpick can be inserted into
• Toothpicks

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Activity cont.

• Instructions
• Designate each color of gumdrops a different base
  (Ared, Tgreen, for example)
• Designate the toothpicks as the bonds between the
  bases
• Give the students a list of bases that ranges
  from 10 to 15 bases long
• The students will then lay out the sequence using
  the gumdrops and the sticking toothpicks into the
  sides

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Activity Instructions cont.

• The students must then decide the complimentary
  pair for each base and connect it to the given
  base
• (to make a double helix other toothpicks must be
  used on the outer sides of the bases to connect
  the pairs of bases together in a rotating matter)

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Example
Given Gumdrops
Toothpicks to hold bonds together in rotating
matter
T
A
Complimentary Gumdrops
A
T
C
G
Toothpicks