What does “DNA” stand for? Deoxyribose Nucelic Acid 1

What does “DNA” stand for?

Deoxyribose

Nucelic

Acid

1

What is the function of DNA?

To store & encode biological information.

Information on how to construct RNA and protein molecules.

Proteins are involved in various cellular functions: Structural support Catalyzing chemical reactions Immune defense Transportation of molecules

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What does DNA look like?

Long double stranded helical molecule (twisted ladder)

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How is DNA organized in eukaryotic cells?

DNA is wrapped and coiled numerous times into chromosomes.

It is stored inside the nucleus.

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http://www.dnalc.org/resources/3d/07-how-dna-is-packaged-basic.html

How is DNA organized in prokaryotic cells?

It is loosely stored in the cytoplasm of the cell. Usually found in a circular form

called plasmid.

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NUCLEUS vs CHROMOSOME vs GENE vs DNA

The NUCLEUS is where DNA is stored in eukaryotic cells.

DNA is the material that makes up genes and chromosomes. Stretched and unwound it looks like a double helix. .

The term CHROMOSOME is tightly wound DNA.

The term refers to a GENE small section of the DNA, it codes for a particular trait (ex. freckles).

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Basic Structure of DNADNA is a twisted double stranded helix.

DNA Base Pairing Rules

Adenine (A) bonds with Thymine (T)

Cytosine (C) bonds with Guanine (G)

A T C G

“All Tigers Catch Gators”

Nitrogenous Base Pairs

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Sugar phosphate backbone

Basic Structure of DNA3

WEAK hydrogen bonds

STRONG covalent bonds

If you unwound the double helix this is what it would look

like. The building blocks of DNA are called NUCLEOTIDES

Nitrogenous

There are 4 types of

nitrogenous bases: A, T, G, C.

Strand #1 Strand #2

Almost every cell in your body needs a complete copy of DNA.

Your DNA will make new copies of itself with your body makes new cells during MITOSIS!

http://www.dnalc.org/resources/3d/01-replication-the-helix.html

Pretend you are DNA Polymerase (an enzyme that builds DNA molecules). Complete the complementary base strand for the following 3 gene segments.

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Strand #1: T A C G C C T A T G C T A T G C C A Strand #2: A T G C G G A T A C G A T A C G G T

Strand #1: G C C T A C G T T C G A A G C C C T Strand #2: C G G A T G C A A G C T T C G G G A

Strand #1: A A A G T C C T A C C A A T A G C C Strand #2: T T T C A G G A T G G T T A T C G G

Pathway of Protein Synthesis

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The weak hydrogen bonds are broken. This opens the DNA at a particular gene section. A copy of the gene’s DNA called RNA is made.

2The RNA leaves the nucleus and goes to the cytoplasm within the cell. It attaches to a ribosome.

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The ribosome “reads” the RNA and assembles amino acids into a chain. This chain will become a protein and be released.

DNA

RNA

RNA leaving the nucleus

ribosome

amino acids

Amino acid chain (polypeptide chain)

http://www.youtube.com/watch?v=suN-sV0cT6c

TRANSCRIPTION

DNA gene RNA

DNA can never leave the nucleus, so it creates a “copy” called RNA to send genetic information outside the nucleus to the ribosomes.

RNA has different properties than DNA.

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RNA Base Matching Rules

Uracil (U) bonds with Adenine (A)

Adenine (A) bonds with Thymine (T)

Cytosine (C) bonds with Guanine (G)

Guanine (G) bonds with Cytosine (C)

DNA RNA A U T A G C C G

http://www.dnalc.org/resources/3d/12-transcription-basic.html

http://www.youtube.com/watch?v=NJxobgkPEAo

RNA vs DNAUse the following words to fill in the comparison chart:

Double stranded Single stranded Ribose Sugar

Deoxyribose Sugar Can leave the nucleus

Can not leave the nucleus Adenine Thymine Guanine Cytosine

Uracil Phosphate

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Pretend you are RNA Polymerase (an enzyme that builds RNA molecules). Make three RNA molecules that will code for proteins.

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Strand #1: T A C G C C T A T G C T A T G C C A Strand #2: A U G C G G A U A C G A U A C G G U

Strand #1: G C C T A C G T T C G A A G C C C T Strand #2: C G C A U G C A A G C U U C G G G A

Strand #1: A A A G T C C T A C C A A T A G C C Strand #2: U U U C A G G A U G G U U A U C G G

TRANSLATION The 2nd phase of protein synthesis. RNA is “read” by the ribosome to make an amino acid chain.

Amino Acids are building blocks for proteins. The are 20 types of amino acids. Different combinations of amino acids makedifferent proteins.

Every three bases on RNA is known as a codon. It will code for 1 amino acid.

Amino acids are connected by peptide bonds in the ribosome.

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http://www.dnalc.org/resources/3d/15-translation-basic.html

http://www.youtube.com/watch?v=5bLEDd-PSTQ

Gln

GluAsp

Asn

Pretend you are a ribosome and you just received RNA (mRNA) strands. TRANSCRIBE these messages into proteins (aka polypeptides, amino acid chains).

RNA: AUG UUU GCA CGA UGG AAG CCC UGA

Amino Acid Chain: Met -- Phe -- Ala -- Arg -- Try -- Lys -- Pro -- Stop

RNA: AUG CUU GAA AAA CCG UAC ACC UAA

Amino Acid Chain: Met -- Leu -- Glu -- Lys -- Pro -- Tyr -- Thr -- Stop

RNA: AUG GAU CGA GGG AAU UAC AAC UAG

Amino Acid Chain: Met -- Asp -- Arg -- Gly -- Asn -- Ser -- Asn-- Stop

Genetically Modified Organisms

(GMOs)

1. Watch the video on GMOs.

http://video.foxnews.com/v/2542413631001/what-are-gmos/

2. Write down three researchable questions that would help you learn more about GMOs.

What is a GMO? GMO: genetically modified organism, created

through transgenic engineering.

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CONVENTIONAL FARMING

ORGANIC FARMING TRANSGENIC ENGINEERING

•Traditional selective breeding method

•Sprays chemicals to reduce pests (herbicides, pesticides, insecticides, fungicides).

•Chemical fertilizers

•Animals are given antibiotics & growth hormones

•Traditional selective breeding method

•Organic pesticides are used to reduce pests

•Organic fertilizer, manure

•Animals graze on grass or organic feed

•No chemical additives are added to processed foods

•New method of breeding plants and animals.

•Desired genes from one species can be transferred to a different species.

•The modified species will produce a new protein that will promote the desired characteristic.

• The use of GMO’s is prohibited in organic products.

A group of similar organisms that can successfully breed AND produce fertile offspring.

Species

GMO example http://www.youtube.com/watch?v=W1xbk7M1yIo

How are GMO’s

created?

• Using a restriction enzyme, a desired gene is “cut out” from DNA of a species.. • The plasmid is snipped open using the same restriction enzyme.

• The species’ DNA is inserted into the plasmid & the plasmid is returned to the bacteria cell.• The bacteria cell will reproduce new bacteria cells with the new DNA. Each new bacteria cell will create the new protein (that the other species normally makes).

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Restriction Enzymes: enzymes that cut DNA at a particular location

#1. Nutritionally enhance food products (ex. Golden rice)

Is 10% better than nothing?

Suggested Reasons to Grow/Eat Genetically Modify Organisms

#2. Slow down ripening of fruits/vegetables (ex. Flavr Savr ® tomato)


#3. New Tolerance to some of the following possibilites: Pathogenic bacteria or viruses (ex. Papaya) Herbicides (ex. Roundup Ready ® corn) Insects (ex. Bt Corn) Harsh weather (drought, cold weather)


#4. Increases food production (growth rate and yield)

Suggested Reasons Grow/Eat Genetically Modify Organisms

#5. Other “convenient” needs (ex. Arctic apple ®, Glo Fish ® )

Suggested Reasons Grow/Eat Genetically Modify Organisms

Are there RISKS associated with GMO’s?

#1. Risk of pollen-pollution caused by cross pollination. Pollen from a GM plant is

passed along to another plant by wind, bees or other natural uncontrollable ways.

Suggested Reasons AGAINST Genetically Modify Organisms

#1. Risk of unintended harm to other plants and animals.


#3. May cause the emergence of pest, insect or microbial resistance to traditional pest

control methods


#4. Risk of unknown side effects for humans.


#5. Risk of creating a monopoly and dependence of farmers on companies who are seeking control of the world’s commercial seed supply. This is sometimes due to patent laws.


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What does “DNA” stand for? Deoxyribose Nucelic Acid 1