Mr. Bouyer
Day 1 - 2 | Day 3 | Day 4 - 5 | Day 6 | Project or Lab | Vocabulary Test

This Week's

Deoxyribonucleic acid Polymer Nucleotide Double helix Deoxyrobose sugar Ribose sugar Nitrogen bases Purines Adenine Guanine Pyrimidines Thymine Cytosine Uracil Phosphate Base-pairing Replication Chromosome Gene Allele	Chromatid Homologous Diploid Haploid Ribonucleic acid Messeanger RNA Transfer RNA Ribosomal RNA Transcription Protein synthesis Translation Gene pool Hybrid Hybrid vigor Gregor Mendel Genotype Phenotype Homozygous Heterozygous Monohybrid Dihybrid	F1 generation F2 generation Probability Punnett Square Heredity Karyotype Polygenic trait Multiple-allele Sex-linked X-linked Y-linked Sex-influenced Genetic engineering Clone Plasmid Recombinate DNA Gene therapy Population sampling Pedigree Eugenics

DeoxyriboNucleic Acid

DNA is a complex molecule (polymer) found in all living things.

The primary function of DNA is to store and transmit genetic information that tells cells which proteins to make and when to make them.

Polymers are complex molecules composed of repeating subunits. The repeating subunits in DNA and RNA are called nucleotides.

In 1953, James Watson and Francis Crick proposed a model for the DNA molecule that consisted of two nucleotide chains that wrap around each other to form a double spiral. This shape is called a double helix. The picture at the top of this page represents a double helix.

Each nucleotide is composed of:

A Sugar:

• Deoxyribose - a 5-carbon sugar in DNA
• Ribose - a 5-carbon sugar in RNA. This sugar has more oxygen than the sugar in DNA.

• Purines - have a double ring of carbon and nitrogen atoms.
  • Adenine
  • Guanine
• Pyrimidines - have a single ring of carbon and nitrogen atoms.
  • Thymine
    • Thymine is replaced by uracil in RNA.
  • Cytosine

Base-pairing rules: these rules describe the behavior of the bases. Cytosine always bonds with guanine by forming three hydrogen bonds. Adenine always bonds with thymine by forming two hydrogen bonds. A pair of bases that always bond together is known as a complementary base pair.

Replication the process of duplicating the DNA molecule.

An idea about size: An average cell nucleus is about 6 micrometers in diameter. The total length of the DNA in the human genome is 1.8 meters. There must be several levels of coiling and supercoiling in DNA.

End Of Instruction practice test question #7

Chromosome:
a coiled, double rod-shaped form of condensed DNA that forms during cell division.

DNA is normally found in long strands in the cell nucleus. The coiled structures we call chromosomes are found in cells only during cell division. DNA is duplicated prior to cell division. When the chromosomes form, one side of each chromosome consists of the original cell DNA while the other side consists of the duplicated DNA. One half of each chromosome goes to both cells during cell division. This insures that the new cell will have exactly the same genetic make-up as the original cell.

Every species has a distinct number of chromosomes.

Other important terms:

Gene - a segment of DNA on a chromosome that controls a particular trait.
Allele - any of the several alternative forms of a Gene.
Chromatid - one of two identical halves of a chromosome.
Homologous chromosomes - the two members of each pair of chromosomes.
Diploid - 2N - a cell that contains both chromosomes of a homologous pair.
Haploid - N - a cell containing only one chromosome of a pair.

End Of Instruction practice test question #37

Bioinformatics Scientist

RiboNucleic Acid RNA is responsible for the movement of genetic information from the DNA in the cell nucleus to the site of protein synthesis in the cytoplasm. RNA's sugar molecule is ribose instead of the deoxyribos sugar in DNA.

Types of RNA: Messenger RNA - mRNA - a single uncoiled strand that transmits information from DNA to the ribosomes during protein synthesis. Transfer RNA - tRNA - a single folded strand that bonds with a specific amino acid. Ribosomal RNA - rRNA - a globular form that is the major constituent of the ribosomes.

Transcription - the process of forming a mRNA strand from a DNA strand.

• The DNA double strands are separated and a mRNA strand is formed by RNA bases pairing up with the exposed DNA sequence and each base linking to the next.
• The mRNA that is formed carries the genetic information that will be translated into a protein.
• The rate of transcription is about 40 nucleotides per second.

Protein synthesis the formation of proteins using information coded on DNA and carried out by RNA.

Translation the assembling of protein molecules from information encoded in mRNA.

The central points on this page are: DNA duplicates itself in replication. DNA produces RNA in transcription. RNA produces proteins in translation.

In-Class Assignment 042:
This assignment must be turned in by the end of class tomorrow to receive credit.
Scoring criteria

Write the answer to each of these questions as a statement.
For example; The intended purpose of the U.S. Immigration Act of 1924 was ........

1. Use this time-line to answer the following questions:
   1. What was the intended purpose of the U.S. Immigration Act of 1924?
   2. How many U.S. states had compulsory sterilization laws in 1931?
   3. The first recombinant DNA molecule was produced in 1972 by what person?
   4. What event happened in 1978 that can be considered the dawn of biotechnology?
   5. How did the U.S. Army begin using biotechnology in 1992?
   6. In what year did scientists first successfully transfer DNA from one life form into another?

2. What is the primary function of DNA?

3. How are the nitrogen bases in RNA different from the nitrogen bases in DNA?

4. How is the shape of the three types of RNA different?

5. The nitrogen bases of DNA always combine in specific pairs. Which bases always bond together?

6. What is the 2N number for a house fly?

7. Use your own words to describe what happens in each of the following processes:
   • replication
   • transcription
   • translation

Research Links:

• Glossary of Genetic Terms - National Human Genome Research Institute
• Control of DNA Replication - Salk Institute for Biological Studies
• Molecular Biology Desk Reference - National Institutes of Health
• Biochemistry Page - Indiana State University
• Molecular Biology Protocols - US Dept Commerce, Microbial Pathogens Lab
• The Human Genome - Oak Ridge National Laboratory
• GenLink - Washington University, St. Louis, MO
• GeneCards - Weizmann Institute of Science, Israel

Biology Class

A normal human body cell has 46 chromosomes.