Science

Bases are held together by a...

hydrogen bond

How do Watson and Crick propose to demonstrate DNA structure?

.They propose to demonstrate with model building.

On Saturday, February 28th, 1953, what did Watson & Crick declare is the pub that that they have found?

.They said that they had discovered the secret of life.

Who was Watson's office mate?

.Wastson's office mate was Francis Crick.

Chromosomes

* made of DNA and proteins *hold all of the information for traits *responsible for the passing of traits to new cells/offspring *control all life functions *can have mutations *23 homologous pairs of chromosomes in every human cell = 46 chromosomes total

Amino acids vs. Proteins

*Amino acids - building blocks of proteins. *Amino acids link together by a peptide bonds forming a chain in a particular order and length. *There are 20 different amino acids that come together in different combinations to make up thousands of different proteins. *Proteins - a long chain of amino acids joined together *Proteins are essential for the structure, function, and regulation of the body's blood cells, tissues, and organs.

Mutations: Cancer

*Cancer is a genetic disorder that affects the cell cycle. *These cells rapidly divide. They can spread and invade many different tissues of the body. *While some cancer mutations can be inherited, most cancers are caused by mutations to DNA that happen during a person's lifetime. *Some mutations come from mistakes made during replication, but many are caused by harmful substances often referred to as carcinogens . *Examples include: cigarettes, radiation and chemicals (like pesticides).

Erwin Chargaff

*Chargaff's rules: *base pairs are complementary *the amount of adenine in DNA always equals the amount of thymine *the amount of guanine in DNA always equals to the amount of cytosine

genes

*DNA contains genetic information *genes are located on sections of our DNA *genes are the functional and physical unit of heredity passes from parent to offspring * most genes contain the information for making a specific protein *proteins are responsible for determining the color of a flower, the shape of a leaf, a human blood type and even the sex of a newborn baby

What does DNA look like?

*DNA is made of subunits called nucleotides *nucleotides consist of three parts; a phosphate, a deoxyribose sugar, and a nitrogen base

Selective Breeding

*Even before we had knowledge of DNA and specific genes, we knew we could select favorable traits in organisms to better serve humans. * Selective Breeding is the process of selecting and breeding parent organisms to pass on particular traits to their offspring. *Examples: are domesticated dogs from wolves, various livestock, cats, etc.

DNA Identification or DNA Fingerprinting

*FBI's forensic DNA identification system probes 13 regions in the human genome. Sequences at all 13 sites must line up to prove a DNA match, but it only takes one sequence to prove a mismatch. DNA evidence has been used to liberate a growing number of people who were falsely imprisoned for crimes they did not commit *What other ways can this be used? *Identify a person who committed a crime *Identify family relations *Identify hereditary diseases

Causes of Mutations

*Mutagen - any physical or chemical agent that can cause a mutation *Example: cigarette smoke, asbestos, x-rays, ultraviolet radiation *Carcinogen - Mutagens that are believed to increase the risk of a cancer.

Mutations

*Mutations are changes in the number, type or sequence of nucleotides (letter arrangements) on a DNA molecule *Example: sickle cell anemia, frog with an extra leg

nucleotides

*Nitrogen bases are linked in pairs which are held together by a hydrogen bond *nucleotides are linked together in pairs and are stacked pair on top of pair to form a long strand of DNA

How does a mutation occur?

*Random error when DNA is copied *Damage from a mutagen

Protein Synthesis

*Since DNA contains all the information for making proteins but cannot move out of the nucleus, the cell needs the help of RNA. *RNA, ribonucleic acid, is a molecule similar to DNA that can move around the cell. *RNA is a one-sided molecule and contains uracil instead of thymine.

3 Types of Mutations

*Substitution - when one letter is changed with another (think of a soccer player being substituted for another player) *Insertion - an extra letter is added to the sequence *Delection - one letter is omitted from the sequence

Protein Synthesis Defined

*Synthesis - means the combination of *Protein Synthesis - is the process in which proteins are made from the coded information located on DNA. *There are two parts to protein synthesis: Part I - Transcription Part II - Translation *Each section of DNA that codes for a protein is called a gene. *Humans have 20,000-30,000 genes.

DNA replication

*first, a special chemical called an enzyme breaks the hydrogen base that holds the bases together *this causes the two sides of the DNA molecule to separate of "unzip"

Three types of RNA

*rRna - "ribosomal RNA" and makes up the ribosomes. *mRNA - codon- "messenger RNA" and travels into the nucleus to read the DNA molecules' codons. *tRNA - anticodon- "transfer RNA" that will translate the message and pick up the proper amino acids to assemble into a protein.

DNA replication

*replication means to make a copy of *cells make a copy of their DNA before they can divide into 2 new cells *replication occurs during interphase *replication of DNA must occur so that each new cell has a complete set of DNA -- the same number of chromosomes as the parent cell *ex. if the parent cell has 46 chromosomes, then each new cell will also have 46 chromosomes

The structure of DNA is...

*the 2 sides or "Handrails" of the DNA molecule are made up of alternating molecules of a deoxyribose sugar and a phosphate *each side is in the reverse direction or antiparallel

James Watson and Francis Crick

*used Rosalind Franklin's data to build the first model of DNA *a nobel prize was awarded to Wilkings, Watson and Crick

Rosalind Franklin

*working with Maurice Wilkings, Franklin took the clearest picture of the DNA molecule using X-ray diffraction, which showed there were to forms of DNA

Who do Watson and Crick "acquire" Franklin's unpublished data?

.Watson and Crick get the unpublished data from Morris Wilkins, the director of her lab.

Where does Watson end up getting a position?

.Watson ended up getting a position in the Cavendish at Cambridge.

What school (college) did Rosalind Franklin attend?

.Cambridge Newnham College ( a women's part of the school)

What organisms did Oswald Avery experiment with DNA transfer to determine the link between DNA and heredity in 1943?

.DNA from a disease causing strain of bacteria into a harmless strain. It showed that one organism can be transformed into another because of DNA.

What was her main assignment when Rosalind started there in 1951?

.Discovering the structure of DNA.

Who were two of the most determined DNA scientists in this field?

.Francis Crick and James Watson

Who was supposed to be in charge of Rosalind in the lab?

.Franklin Gosling.

What is x-ray crystallography?

.It's a technique that reveals the hidden atomic structure in its crystalline form, Atoms are too small to see under light microscopes so crystallographers shoot invisible x-rays at them which then bounce off or diffract onto a detector such as film by applying math to the diffraction pattern, it's possible to calculate the three dimensional form of even the most complex molecules.

Describe what DNA looks like when the Scientist Kimberly Mowry is pulling it from the beaker.

.It's really beautiful and it is responsible for the blueprint of the cells. It is goopy and gel-like that is white and clear. It looks like slime and very sticky with like cotton candy when you put it on a stick. Very thick strands that look like cotton. It also looks like cobwebs.

Who "enters the game" while setting up the lab at King's?

.James Watson had "entered the game".

Where in England was Rosalind offered a position?

.King's College in London a highly prestigious research center

Where did Rosalind work when she later moved to Paris and what did she perfect when she worked there?

.Laboratoire central and she perfected her technique in x-ray diffraction.

(BONUS): Where did the assistant (Mrs. Heller) graduate from in the letter Aaron Klug speaks of?

.MRs. Heller graduated from Syracuse.

Did Watson's colleagues think the book was an accurate description of the discovery?

.No Francis Crick wrote that his book was misleading and in bad taste it does not illuminate the process of scientific discovery it distorts it.

What is she later diagnosed with and what is the probable cause?

.Rosaland was later diagnosed with severe cancer after she had come back from her trip on her birthday. The cause for this was from all of her x-ray work.

What does Franklin finally name her best "B form" picture?

.She names the picture "photo 51".

What year and where was Rosalind Franklin born?

.She was born in London in 1920

What new nickname does she acquire after this?

.The Dark Lady is the new name that she acquires

What is the title of James Watson's book?

.The Double Helix

What was Rosalind Franklin responsible for?

.The crucial x-ray photo

What nickname was Rosalind given that Watson later "popularizes"?

.The nickname that Rosalind was given was Rosie.

How many angstroms per "turn" is the DNA molecule?

.There are 34 angstroms per "turn"

How many forms of DNA does Rosalind initially photograph?

.There were two distinct forms of DNA

What were Rosalind's first experiments concerned with and how did they contribute to the war effort?

.her first experiment was with coal. It contributed to the war effort by creating a better gas mask, a valuable contribution to England under attack.

What often forced Rosalind to suspend her work for weeks at a time?

.she had been exposed to too much x-ray

What did Watson and Crick realize about how DNA replicates?

.they realized that unzipping the helix produces two new helices identical to another.

Elements of Protein Synthesis

1. DNA Sequence: A, T, C, G are the letters of the DNA alphabet called nucleotides forms a... 2. Codon: Every three nucleotides in a specific sequence forms a word or also called a DNA triplet codes for an ... 3. Amino Acid: each codon indicates the length and order which is needed to build a ... 4. Protein: long chains of amino acids used to determine a ... 5. Trait: Different arrangements of proteins produce different characteristics: hair color, eye color, or blood type.

3 possible consequences to changes in DNA:

1. No effect - no change 2. Minor effect 3. Major effect - The effect can be good, such as a plant having an increased resistance to disease. Or the effect can be bad, causing a deformity, genetic disorder or disease. *Proteins usually detect a mutation and fix it. *If the mutation occurs in sex cells, the changed gene can be passed from one generation to the next.

Part I of Protein Synthesis: Transcription

1. The DNA molecule unzips exposing the gene to be read at a start codon. 2. mRNA travels into the nucleus and "reads" the DNA. It actually reads the opposite side of the DNA and therefore the opposite code, substituting thymine for uracil. 3. mRNA then leaves and travels through cytoplasm.

Steps of DNA replication

1. cell prepares to divide 2. DNA is unzipped at the bases 3. complementary bases are added 4. 2 new strand or 2 new DNA molecules are formed 5. mitosis begins and 2 new cells are created

What year did Watson and Crick receive the Nobel Prize?

1962

Part II of Protein Synthesis: Translation

4. mRNA travels to the ribosomes and passes through the ribosome, causing the approach of tRNA. 5. tRNA "reads" the mRNA, decoding 3 bases at a time, thus returning the code to its original form. 6. tRNA then delivers a specific matching amino acid. 7. The amino acids are assembled into a protein to produce a gene.

Genetically Modified Organisms (GMO)

Along with humans, genomes of other species have also been identified. This has allowed us to genetically modify other species, including organisms that we consume for food. We refer to them as Genetically Modified Organisms or GMOs.

Cloning

Cloning is the creation of a genetically identical organism from one cell. Although clones can happen naturally (identical twins), cloning can be done artificially in a lab using a cell from an organism. Cloning of individual organs is still being researched.

Making of Insulin

Diabetes is a condition where the body cannot produce the hormone, insulin. This results in the inability to control the blood sugar levels resulting in health conditions, like high blood pressure. People who cannot produce insulin have a condition known as diabetes and need to watch the consumption of carbohydrates (sugars). Scientists took the human gene for making insulin. They inserted it into a bacterium. The bacterium copies these genes into many generations of cells. These cells now produce the human insulin protein molecule. This molecule is purified and given to people affected with diabetes. Millions of people with diabetes now take human insulin produced by bacteria or yeast (biosynthetic insulin) that is genetically compatible with their bodies, just like the perfect insulin produced naturally in your body.

Human Genome Project

Scientists decided to map out all of the DNA within our cells. This undertaking was referred to as the Human Genome Project (1990-2003). This required scientists to map out all 3 billion Base Pairs. By doing so, they hoped to find out the sequences/ codes that were inaccurate, which could hopefully lead to curing genetic mutations. However, of all of the base pairs, < 5% are "genes." Most of our DNA is not part of "coding."

Mutations: Sickle Cell Anemia

Sickle cell disease is a severe hereditary blood disorder. Sickled red blood cells tend to break more easily than normal red blood cells. People with sickle cell disease do not get enough oxygen delivered to their body tissues, and the tissues become damaged. The disease is common in Africa, parts of India and the Middle East.

GENETIC ENGINEERING

The science of changing the genetic makeup of an organism to produce a more desired outcome

The structure of DNA is...

The steps or "rungs" of the DNA ladder are made up of pairs of nitrogen bases; adenine, thymine, cytosine, guanine

Glowing Animals

These animals had fluorescent proteins from jellyfish inserted into their DNA and they now GLOW!

DNA

deoxyribonucleic acid

DNA replication

next, the open bases find complementary nucleotide partners, which are found in the cytoplasm *these nucleotides are added to the correct open bases, in sequential order connecting to the sugars and phosphates to makeup the new side of the DNA strand *each new DNA molecule now contains one strand of the old DNA and one strand of the new DNA