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Genetics and DNA.

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Presentation on theme: "Genetics and DNA."— Presentation transcript:

1 Genetics and DNA

2 Traits All of the features that an organism inherits
color of your eyes hair color type of ears

3 DNA Deoxyribonucleic Acid Double Helix- twisted ladder shape
Found in every living cell Contains all the information required to produce a living organism

4 Gene Part of the DNA code on a chromosome
Humans have tens of thousands of genes on every chromosome Contains the genetic make up

5 Genotype The code or genetic make up TT, tt, Tt

6 Phenotype Physical Characteristics
Hair color, type You can tell just by looking at someone Environment influences/effects how the genetic makeup is shown

7 Environmental Effects vary from organism to organism
Competition from other organisms has a great deal of effect on a population An organism’s appearance can change based on the environment.

8 Genetics Study of heredity
Passing of one trait from one generation to the next A rapidly growing field with more and more information about humans and other organisms

9 Gregor Mendel An Austrian, Roman Catholic priest and scientist who is known as the father of genetics He studied the inheritance of traits in pea plants. Image From: Image From:

10 Allele Different forms of a gene T- tall t- short

11 Dominant vs. Recessive Dominant alleles show in an organisms phenotype whenever present in its genotype. Recessive alleles show their effect in an organisms phenotype only when two are present in the genotype

12 Principle of Segregation
Each parent passes only one allele for a trait to its offspring

13 Principle of Independent Assortment
The alleles for a trait do not influence the alleles for another

14 Predicting Genetic Outcomes
Mendel used probability to make predictions Reginald C. Punnett developed the Punnett Square 50 years after Mendel’s work was published When the parent’s genotypes are known, a Punnett square is used to predict the possible offspring

15 Impact over Time Over long time periods, the environment impacts a species’ ability to survive

16 Non Living Influences Include: temperature, rainfall, fire, elevation, volcanic eruptions, periodic flooding and pollution

17 Reasons for Adapting Availability for food, predators, and the number of species living in an area affect a species’ survival Image From:

18 Darwin and Wallace Over time environmental factors can change the genetics of a species Natural Selection Image From:

19 Selective Breeding Humans choose the desired traits in the offspring
Breeders of animals and plants in today's world are looking to produce organisms that will possess desirable characteristics, such as high crop yields, resistance to disease, high growth rate and many other phenotypical characteristics that will benefit the organism and species in the long term.

20 Erwin Chargaff showed that in natural DNA the number of guanine units equals the number of cytosine units and the number of adenine units equals the number of thymine units. Chargaff's research would later help Watson and Crick to deduce the double helix structure of DNA. Image

21 Rosalind Franklin Worked with x-ray radiation to take the first pictures of DNA Died of cancer most likely related to her work with X-rays Image

22 Structure of DNA James Watson and Francis Crick
In 1962 James Watson (1928– ), Francis Crick (1916–2004), and Maurice Wilkins (1916–2004) jointly received the Nobel Prize in medicine or physiology for their determination in 1953 of the structure of deoxyribonucleic acid (DNA). Image From:

23 Image From:

24 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 m. The earth is 150 billion m or 93 million miles from the sun. If you unravel all the DNA in the chromosomes of one of your cells, it would stretch out 2 meters. If you did this to the DNA in all your cells, it would stretch from here to sun more than 400 hundred times!

25 DNA is made of a long sequence of smaller units strung together
DNA is made of a long sequence of smaller units strung together. There are four basic types of unit: A, T, G, and C. These letters represents the type of base each unit carries: adenine, thymine, guanine, and cytosine. The sequence of these bases encodes instructions. Some parts of your DNA are control centers for turning genes on and off, some parts have no function, and some parts have a function that we don't understand yet. Other parts of your DNA are genes that carry the instructions for making proteins — which are long chains of amino acids. These proteins help build an organism.

26 Mutations Process in which DNA changes to form new alleles
Cross eyed, downs syndrome, extra digits, Opposable Thumb Some are advantageous

27 Types of Mutations Substitution A substitution is a mutation that exchanges one base for another (i.e., a change in a single "chemical letter" such as switching an A to a G). Such a substitution could: For example, sickle cell anemia Sickle cell anemia is a genetic disease with severe symptoms, including pain and anemia. The disease is caused by a mutated version of the gene that helps make hemoglobin — a protein that carries oxygen in red blood cells.

28                                  Insertion: Insertions are mutations in which extra base pairs are inserted into a new place in the DNA. Original: The fat cat ate the wee rat. Insertion: The fat cat xlw ate the wee rat

29 Deletion Deletions are mutations in which a section of DNA is lost, or deleted. Muscular Dystrophy:

30 How mutations occur DNA fails to copy accurately Most of the mutations that we think matter to evolution are "naturally-occurring." For example, when a cell divides, it makes a copy of its DNA — and sometimes the copy is not quite perfect. That small difference from the original DNA sequence is a mutation.


32 External influences can create mutations
Mutations can also be caused by exposure to specific chemicals or radiation. These agents cause the DNA to break down. This is not necessarily unnatural — even in the most isolated and pristine environments, DNA breaks down. Nevertheless, when the cell repairs the DNA, it might not do a perfect job of the repair. So the cell would end up with DNA slightly different than the original DNA and hence, a mutation

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