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Biotechnology Bell RingersSeptember 27th, 2010
1. What are some differences between plant cells and animal cells?
2. What two resources were used to examine different examples of cells?
3. Bacteria are prokaryotes. What is a prokaryote?
Biotechnology Objectives September 27th, 2010 (EB04.03)
We will explore the structure of DNA
We will explore DNA’s relationship to the cell
We will Extract DNA from a Strawberry
Time permitting, we will go over some Biotechnology current events
Genetics and DNA
1860s, Gregor Mendel discovered that “factors” determine inheritance in pea plants
He observed that many traits control these factors
Genetics and DNA
1903, researcher William Sutton made connection between Mendel’s “factors” and chromosomes-microscopic structures in the cell nucleus that carry genetic material
Genetics and DNA
The genetic material itself, known as DNA, was discovered by Johann Miescher in Switzerland in 1869
Genetics and DNA
Yet, it wasn’t until two researchers, Francis Crick and James Watson, proposed a double-helix structure for the molecule that we began to understand how this material carries the genetic code of life
Genetics and DNAA gene is a unit of
information that can be passed on to offspring
They are a power influence on physical and mental characteristics
They aren’t just found in people, they are found in all living things
Genetics and DNAAs powerful as genes
are, however, it’s important to remember that environment also helps shape organisms
The interactions between a living thing and its environment affect how it will turn out
Domineering Genes
With few exceptions, every organism has two of each kind of gene
Genes are usually either dominant or recessive
Domineering GenesA dominant gene is
expressed in the offspring no matter what gene the other parent contributes
A recessive gene is expressed in the offspring only if both parents contribute recessive genes
Mutations RuleOver billions of years
the earth has been around, plants, animals, and other living things have evolved through the changing of genes
Genes have been transferred, deleted, and mutated between generations
Mutations RuleMutation has produced
the countless variations of living things we see around us
Many mutations are neutral and have no effect at all
Some mutations place a living thing at a disadvantage
Some mutations, however, give an individual a better chance of survival
This makes them more likely to survive to have offspring
Over time, this mutant gene will likely become established in the gene pool (the genes of a breeding population
Secret CodesDNA holds the secret
code to make and maintain proteins (long chains of molecules that help living things grow and function
But how does this secret code move from the nucleus to the protein-making factories in the cells?
Secret CodesRather than move
the DNA out of the nucleus, the cell makes a copy of the gene(s) and sends it to the protein assembly site outside the cell nucleus
The copy is messenger RNA (ribonucleic Acid)
Secret Codes
RNA is a single-stranded copy of a single cell of a single gene
It carries codes from the DNA to the protein assembly sites outside the nucleus
Genes Across the AgesIn nature, genes generally
are transferred between members of the same species
Some new studies, however, suggest that genes also move between unrelated organisms
For the most part, such “horizontal” gene transfer takes place among bacteria and viruses
Genes Across AgesToday, horizontal gene
transfer also can occur through genetic engineering
DNA can be transferred via direct injection or by inserting the DNA into bacteria or viruses that carry it into the cells they infect
This means that traits determined by single genes can be transferred from one kind of organism to another