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Genetics: Study of Heredity. Aim: What is Genetics?. Sexual Reproduction:. Two parents Half of the genetic information is received from one parent, half from the other. Variation  Evolution. Asexual Reproduction:. One parent

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aim what is genetics
Aim: What is Genetics?

sexual reproduction
Sexual Reproduction:
  • Two parents
  • Half of the genetic information is received from one parent, half from the other.
  • Variation Evolution
asexual reproduction
Asexual Reproduction:
  • One parent
  • Offspring is identical to parent.
  • Clones- identical genetic copies.
  • Gregor Mendel- 1800’s
  • “Father of Genetics”
  • Pea plants: easy to grow
  • Contrasting traits
  • Easily self and cross pollinate.
  • From his studies, Mendel arrived at conclusions that are the basis for genetics today!
additional vocabulary
Additional Vocabulary
  • Genetics: Study of heredity
  • Heredity: Passing of genetic information from an organism to it’s offspring.
Genes: units of heredity
    • Determines traits/ characteristics an offspring will have.
    • Located on chromosomes.
    • For each trait-> minimum of 2 genes. One from mom, one from dad.
  • There are many genes located on a Chromosome.
hereditary information
Hereditary Information:
  • DNA- deoxyribonucleic acid
  • Organic (C, H, O, N, P).
  • Double stranded
  • Organized in the form of genes located on the chromosomes.
hereditary information cont
Hereditary Information:cont.
  • Homologous chromosomes- are same size and shape (one from each parent)
    • This allows for crossing over and variation to occur.

genotype vs phenotype
Genotype vs. Phenotype:
  • Genotype- genes
  • Ex: B,b,S,s
  • Phenotype-Physical appearance
  • Ex: Fur Color, Fur Length

genetic recombination
Genetic Recombination:
  • Sperm and egg combine to form a new cell.
  • New cell (offspring) has a complete set of genetic information (DNA). Each offspring is unique.
the genetic code
Structure of DNA was discovered by 2 scientists:

1953 James Watson and Francis Crick

Created a model known as the Double Helixa twisted ladder.

The Genetic Code:
structure of dna
Structure of DNA
  • Long chain of repeating units ( polymer) called nucleotides.
  • A nucleotide unit contains:1. phosphate group O2. deoxyribose (sugar)3. nitrogenous base:
    • A- adenine
    • T- thymine
    • C- cytosine
    • G- guanine
one strand of dna
One Strand of DNA


  • The backbone of the molecule is alternating phosphate and deoxyribose, a sugar, parts.
  • The teeth are nitrogenousbases.



two stranded dna
Two Stranded DNA
  • Remember, DNA has two strands that fit together something like a zipper.
types of nitrogen bases
A= adenine

G= guanine

C= cytosine

T= thymine

Types of nitrogen bases
structure of a double helix
Structure of a Double Helix
  • Sides of the “ladder” are alternating phosphate group and deoxyribose sugar.
  • “rungs” of the ladder are made of 2 nitrogenous bases.
  • Specific pairings:
    • There is a weak Hydrogen bondBetween the base pairs.
    • Structure as a double helix
    • When a cell goes through mitosis(cell division) the DNA must also make a copy of itself.
dna by the numbers

The earth is 150 billion m

or 93 million miles from

the sun.

DNA by the numbers
  • Each cell has about 2 m of DNA.
  • The average human has 75 trillion cells.
  • The average human has enough DNA to go from the earth to the sun more than 400 times.
  • DNA has a diameter of only 0.000000002 m.
aim how does dna replicate
Aim: How does DNA replicate?

Do Now: Please answer the questions on the handout found on the front desk, omit questions 5-7.

g enetics c an t ell a ll
Genetics Can Tell All





base pairing
Base Pairing
  • Which bases always match up?
  • A-T
  • G-C
  • Adenine always binds with Thymine
  • Cytosine always binds with Guanine
steps of replication
1.DNA unwinds

2. DNA unzips

3. Old strands become templates for new strands

4. Result- 2 identical DNA molecules

Steps of Replication:
characteristics of a double helix
Characteristics of a Double Helix
  • Proteins and Cell Functioning:
    • Proteins- long chains formed from 20 kinds of amino acids.
    • Sequence(order) of the amino acids influences the shape of the molecule.
    • Proteins include: enzymes, insulin, eye color, and skin color.
dna protein connection
DNA- Protein Connection:
  • Genes contain coded information.
  • This information is used to make proteins that are required for it’s function and structure.
  • Ribosomes construct proteins based on the cell’s DNA code (combo of A, C, T, G’s).
  • Parent and offspring produce similar traits that is why there is resemblance between them. They produce similar proteins.
protein synthesis
Protein Synthesis:
  • The building of protein molecules.
  • Synthesizing protein from DNA.
  • Proteins are chains of amino acids.
  • Begins in the nucleus with DNA.
  • DNA code is read by a “ messenger molecule” messenger RNA; ;
  • mRNA.
  • “messenger molecule: travels into the cytoplasm of the cell to the ribosome.
steps cont
Steps cont.:
  • With the help of “transfer molecules” tRNA amino acids move to the ribosomes to make proteins.
  • The ribosomes “reads” the code and a chain of amino acids is produced forming a protein.
  • ***Protein structure is determined by DNA***
  • Ribonucleic Acid
  • Single stranded
  • Nitrogenous bases
    • A- adenine
    • U- uracil
    • C- cystosine
    • G- guanine
types of rna
Types of RNA
  • Messenger RNA (mRNA)Copies code from DNABrings to ribosome
  • Transfer RNA (tRNA)Brings amino acids to ribosome for protein assembly
  • Mutations:Alteration of DNA sequence.Causes a change in code carried for by the gene.Random, but can be increased because of chemicals, radiation.
aim what are different genetic mutations
Aim: What are different genetic mutations?
  • Do Now: Please complete the handout on the front desk.
different types of mutations
Different Types of Mutations:
  • Original DNA Template C A A T G C T A C
    • 1. Substitution: one base pair for another.C A A C G C T A C
    • 2. Deletion: missing a base.C A A T O C T A C
    • 3. Addition: adding an extra baseC A A T A G C T A C
    • 4. Inversion: bases are rearranged.C A G A T C T A C
causes of mutations
Causes of Mutations
  • Environmental Conditions can affect how genes are expressed.
    • Ex. Himalayan rabbit
    • Warmer body temperature white fur
    • Colder body temperature black fur
  • ** Identical twins- separated- different personalities
  • Chemicals, hormones can activate a gene, causing certain proteins to be produced.
genetic engineering
Genetic Engineering
  • Used to alter instructions in organisms.
  • Produce more desirable traits.
selective breeding
Selective Breeding:
  • Produces animals and plants with desirable traits.
  • Horse & donkey= mule. (outbreeding)
  • Ex. Larger, juicier fruits…
  • Pure dog, pure cat. (inbreeding)
breeding continued
Breeding continued:
  • ** In sexually reproducing organisms only mutations found on sex cells can be inherited by the offspring.
  • Mutations occurring in body cells will only affect that organism.
dna and individuality
DNA and Individuality:
  • The order of the nitrogenous base pairs, A,T,C,G’s are what makes each person an individual and unique. This is because the order allows for certain proteins to be produced.
  • In an organism every cell contains the same genetic code.
  • However, each cell is different: hair cells, skin cells, liver cells, stomach cells.
gene expression
Gene Expression.
  • Each cell only uses some of the genetic information from the chromosomes.
  • Certain parts of the chromosomes get “turned on” or “turned off.”
gene manipulation
Gene Manipulation:
  • Altering genes using enzymes
  • By manipulating the DNA in plant cells or animal cells; favorable offspring can be produced
  • Produce bacteria that can be beneficial.
  • Cut DNA segment with enzymes
  • This segment can be spliced (moved) and attached to DNA of a new organism.
  • New organism will make the protein coded for by DNA code.
Apply technology to biology.

Applications of Biotechnology:

By using gene therapy and applying it to modern medicine scientists may:

Produce hormones, enzymes and other body chemicals.

Provide at a low cost.

Provide a purer form.