DNA DNA stands for Deoxyribonucleic acid 1 It

DNA

DNA stands for Deoxyribonucleic acid 1. It is present in all living organisms as the main component of chromosomes. It is the carrier of genetic information from one generation to the next. 2. It is an organic molecule that is known as a nucleic acid.

Importance of DNA 1. It carries genetic information from one generation to the next. 2. DNA sequences create genes which then build proteins that determine inherited traits. 3. DNA can be easily copied during the creation of new cells.

Where is DNA located?

Where is DNA located? 1. DNA is found inside a special area of the cell called the nucleus. 2. Because the cell is very small, and because organisms have many DNA molecules per cell, each DNA molecule must be tightly packaged. 3. This packaged form of the DNA is called a chromosome. 4. An organism's complete set of DNA is called its genome.

Structure of DNA 1. DNA is a long molecule made up of units called nucleotides. 2. Each nucleotide is made up of three basic parts: • • • 5 -carbon sugar (deoxyribose) phosphate group nitrogenous base

N U C L E O T I D E

There are 4 kinds of Nitrogenous bases Adenine Guanine Cytosine Thymine

DNA is a double helix in which two strands are wound around each other. Nucleotide Hydrogen bonds Sugar-phosphate backbone Key Adenine (A) Thymine (T) Cytosine (C) Guanine (G)

Complimentary Base Pairing 1. The two DNA strands are held together at the nitrogenous bases by weak hydrogen bonds. The bases will always pair up in the following way: • Adenine bonds to Thymine A-T • Cytosine bonds to Guanine G-C 2. Memory helper: All Teachers Go Crazy!

Check for Understanding of DNA Structure 1. What is the name of the sugar? 2. What is the symbol used to represent the sugar? 3. Name the 4 nitrogenous bases. 4. Name the complimentary base pairs. 5. What type of bonds hold the bases together?

Check for Understanding of DNA Structure (Answers) 1. What is the name of the sugar? deoxyribose 1. What is the symbol used to represent the sugar? 3. Name the 4 nitrogenous bases. adenine, thymine cytosine, guanine 4. Name the complimentary base pairs. adenine – thymine cytosine - guanine 5. What type of bonds hold the bases together? hydrogen bonds

When will DNA replication occur? • DNA replication is the process of copying a DNA molecule • DNA must replicate during cell division so that the genetic information can be passed to the daughter cells. • In order to direct cell functions DNA must replicate itself and send the information out of the nucleus because the DNA is not permitted to leave the nucleus.

DNA Replication Process 1. The DNA separates into 2 strands. It unzips itself with the help of an enzyme called DNA polymerase. 2. Each parent (old) strand serves as a template (model) for making a new DNA strand complimentary to itself. 3. Replication results in 2 daughter strands each consisting of an old DNA strand a new DNA strand.

Your Turn! DNA Replication Following base pairing rules, create a new DNA molecule A T A T A CG C G GC G C Parent New DNA Polymerase Unzips the DNA + C G G C New Parent

DNA Fingerprinting (Gel Electrophoresis)

What is DNA Fingerprinting? 1. It is a technique used to compare DNA samples from different sources. 2. It can be used to: • solve crimes • determine paternity • establish evolutionary relationships.

Gel Electrophoresis Diagram DNA plus restriction enzyme Power source Longer fragments Shorter fragments Mixture of DNA fragments Gel DNA FINGERPRINTING

Gel Electrophoresis Photograph

DNA Fingerprinting Process 1. Each DNA sample is “cut up” using restriction enzymes. 2. A few drops of each “cut up” sample are placed in a well (hole) at one end of the gel material. 3. Electricity is run through the gel and it causes the DNA molecules to move along the gel. 4. Shorter DNA fragments travel farther through the gel and longer ones stay closer to the wells. 5. The gel is treated with a stain to make the DNA visible under ultraviolet light.

Importance of Protein 1. Protein is found everywhere in your body. 2. Every single cell, tissue, muscle and bone contains protein. Protein is essential for providing bone and muscle strength, endurance and immunity. 3. It is estimated that the human body may contain over two million proteins.

Protein Synthesis 1. Genes control the production of proteins which occurs on the ribosomes. 2. Each gene directs the production of a specific protein or special proteins such as hormones and enzymes. 3. The DNA can’t leave the nucleus but it needs to send instructions to the ribosome so proteins can be made. 4. The DNA sends a messenger out to the ribosome that carries the instructions for making the proteins.

What is RNA ? 1. RNA stands for ribonucleic acid and it’s an organic molecule belonging to the nucleic acid group. 2. Messenger RNA is the molecule that is made to carry the instructions to the ribosome so proteins can be made. 3. It is very similar to a DNA molecule but yet different enough that it can cross the nuclear membrane without being recognized as DNA.

Structure of RNA 1. The sugar in the nucleotide is ribose. 2. It is single-stranded. 3. It has uracil for a nitrogenous base instead of thymine. 4. Complimentary base pairs are: Cytosine – Guanine C-G Adenine – Uracil A-U

Making a Protein starts with Transcription is the name given to the process where a DNA molecule makes the messenger RNA molecule in the nucleus.

Translation happens when m. RNA arrives at the ribosome 1. During translation, the cell uses information from m. RNA to produce proteins that are built from amino acids. 2. Two other types of RNA are involved: • • Transfer RNA ( t. RNA) brings amino acids to the ribosome Ribosomal RNA (r. RNA) makes up the ribosome

Translation from RNA into Protein Nucleus Transcription of Messenger RNA Phenylalanine t. RNA Methionine m. RNA Translation by Transfer RNA Ribosome m. RNA Lysine Start codon

The Genetic Code 1. Codons are located on the m. RNA. 2. A codon consists of three nitrogenous bases that code for a single amino acid that is to be added to the growing protein chain. 3. There are just 20 different amino acids that exist. . Example of codons: AUG is the start codon that gets the process going UUC codes for Phenylalanine AAA codes for Lysine

What are Mutations? 1. Mutations are changes in the genetic material of the cell. (DNA) 2. Mutations can be good, bad or neutral. 3. There are 3 different types mutations: • substitutions • insertions • deletions

Substitutions, aka point mutations, occur when one nitrogenous base in the DNA is substituted in place of another one. This mutation only affects one amino acid in the long sequence of a protein. However, it can still have a great impact on the individual.

Sickle Cell Anemia 1. Sickle-cell anemia is a disease caused by the smallest of genetic changes. 2. The protein, hemoglobin, is a single chain of 147 amino acids but because of the single-base mutation, the sixth amino acid in the chain is valine, rather than glutamic acid.

Sickle Cell Anemia 1. Molecules of sickle-cell hemoglobin stick to one another, forming rigid rods. These rods cause a person's red blood cells to take on a deformed, sickle-like shape, thus giving the disease its name. 1. The rigid, misshapen blood cells do not carry oxygen well, and they also tend to clog capillaries, causing an affected person's blood supply to be cut off to various tissues, including the brain and the heart. 1. When an afflicted individual exerts himself or herself even slightly, he or she often experiences terrible pain, and he or she might even undergo heart attack or stroke —all because of a single nucleotide mutation.

Insertions, aka frameshift mutations, occur when one extra nitrogenous base is added into the DNA sequence. Result: 1. All the nitrogenous bases after the insertion will be regrouped into different codons. 2. The protein made will be nonfunctional.

Insertions 1. Cystic Fibrosis (CF) is caused by a mutation in the gene for the protein called cystic fibrosis transmembrane conductance regulator (CFTR). 2. Cystic fibrosis is an inherited chronic disease that affects the lungs and digestive system of about 30, 000 children and adults in the United States (70, 000 worldwide). 3. A defective gene and its protein product cause the body to produce unusually thick, sticky mucus that clogs the lungs and leads to life-threatening lung infections. 4. It also obstructs the pancreas and stops natural enzymes from helping the body break down and absorb food.

Cystic Fibrosis

Deletions Deletion is the loss of genetic material. Any number of nucleotides can be deleted, from a single base to an entire piece of chromosome. Result: 1. Small deletions are less likely to be fatal; large deletions are usually fatal - there always variations based on which genes are lost. 1. Some medium-sized deletions lead to recognizable human disorders.

Neurofibromytosis type I (NF-1) is a tumor disorder that is caused by the mutation of a gene on chromosome 17 that is responsible for control of cell division. NF-1 causes tumors along the nervous system. Common symptoms of NF-1 include: ● Scoliosis (curvature of the spine) ● Learning disorders ● Epilepsy

What causes mutations? There are two ways in which DNA can become mutated: 1. Mutations can be inherited. • Parent to child, because they are present in the egg and sperm cells. 2. Mutations can be acquired • Environmental damage • Mistakes when DNA is copied

What are Mutagens? Mutagens are environmental factors that cause mutations. They include but are not limited to: 1. High temperatures 2. Toxic chemicals (pesticides) 3. Radiation ( nuclear and solar)

Selective Breeding and Genetically Modified Organisms GMO’s

The truth is : ● People have attempted to genetically alter their crops and livestock for years. They would try to improve the taste, size, disease resistance, and many other traits. ● It was called selective breeding !

What is Selective Breeding? 1. It is when animals or plants with desired traits are allowed to reproduce so that these traits are present in the following generations. 2. It may take many generations for characteristics to show up with consistency. 3. Over thousands of years, humans have developed breeds of animals and plants that have desirable characteristics. 4. Most domestic animals are a result of selective breeding efforts.

Examples of Desirable Traits • Dogs that are good hunters. • Cows that produce a lot of milk. • Crops that are resistant to disease. • Horses that can run fast.

What are Genetically Modified Organisms ? 1. They are organisms that have acquired one or more genes through artificial methods. 2. They are sometimes referred to as GMO’s 3. They can be animals, plants or microorganisms.

Genetically Modified Animals ● The FDA Center for Veterinary Medicine(CVM) regulates genetically altered animal products. ● Currently no transgenic animals have been approved for human consumption. ● Transgenic animals have been approved for use as biopharm animals (for producing drugs and hormones) and they produce such products as milk and wool.

Benefits of Genetically Modified Animals Production of animals with specific traits much quicker than with traditional breeding methods. Results in: ● Better quality and increased milk production ● Better quality and increased wool production ● Increased growth rates

Genetically Modified Plants ● ● ● ● Plants are genetically modified to be: Herbicide resistant Pesticide resistant Insect resistant Drought tolerant Extreme temperature tolerant Have added nutrients, such as vitamins and minerals