DNA IN OUR FOOD? EXTRACTION OF DNA FROM STRAWBERRIES (GETTING THE - - PowerPoint PPT Presentation

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DNA IN OUR FOOD? EXTRACTION OF DNA FROM STRAWBERRIES (GETTING THE - - PowerPoint PPT Presentation

Oct 03, 2023 236 likes •635 views

DNA IN OUR FOOD? EXTRACTION OF DNA FROM STRAWBERRIES (GETTING THE DNA OUT OF STRAWBERRIES) -OR ANYTHING ELSE- QUESTIONS TO PONDER WHAT IS DNA? WHERE IS IT FOUND? CAN YOU SEE DNA? WHAT DOES IT LOOK LIKE? WATCH THIS!

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DNA IN OUR FOOD?

EXTRACTION OF DNA FROM STRAWBERRIES (GETTING THE DNA OUT OF STRAWBERRIES)

  • OR ANYTHING ELSE-
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SLIDE 2

QUESTIONS TO PONDER

  • WHAT IS DNA?
  • WHERE IS IT FOUND?
  • CAN YOU SEE DNA?
  • WHAT DOES IT LOOK LIKE?
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SLIDE 3

WATCH THIS!

https://www.youtube.com/watch?v=J3Pf1XKrn-Q

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I NOTICE…

AS A GROUP , FINISH THE SENTENCE… WRITE THIS DOWN ON AN INDEX CARD/POST-IT NOTE

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I WONDER…

AS A GROUP , FINISH THE SENTENCE… WRITE THIS DOWN ON AN INDEX CARD/POST-IT

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HOW DO YOU GET THE DNA OUT OF THE STRAWBERRY?

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PLANT CELL

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GETTING THE DNA OUT!

5 steps:

  • 1. Make the extraction buffer.
  • 2. Squishing the strawberries (Manual tissue disruption)
  • 3. Breaking open cells (Lyse cells)
  • 4. Making sure the DNA does not have a charge

(Neutralization of DNA polarity)

  • 4. Getting the DNA out using alcohol (DNA extraction)
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SLIDE 9

Extraction buffer consists of: detergent, salt and water.

Step 1: Make the extraction buffer

+ + =

Extraction Buffer

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SLIDE 10
  • 2. Squishing the strawberries (Manual tissue disruption)
  • Squish the strawberries with physical force (hands)
  • Massage gently

Step 2: Getting the DNA out!

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SLIDE 11

Step 3. Breaking open the cells (Lyse cells)

a) Break open the cells with a extraction buffer containing soap or detergent to destroy the fats and lipids that make up the cell membrane Soaps work via polar interactions

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  • 3. Making sure DNA does not have a charge

(neutral)

  • Add salt (NaCl) to neutralize the

negative charges on DNA

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The role of electric charge and polarity

  • Water is polar which means that it has both a positive and a negative

side.

  • It forms a “hydration shell” around ions.
  • This is what it means to be soluble (does salt disappear when you put it in

water and stir? This means it is soluble.)

  • In order for a molecule to be soluble in water, it needs to be a polar

molecule or have a charge (negative or positive.)

DNA-

Water

  • 3. Making sure DNA does not have a charge(neutral)
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SLIDE 14

The positively charged sodium ions neutralize the negative charge

  • n the DNA, making it less hydrophilic less soluble in water.

This is how we separate DNA from all the other cellular components

Why do we add more salt (NaCl) Na+ ions:

They out-compete the water molecules

Positive and negative charges cancel each other

  • ut. DNA is now neutral.

DNA

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SLIDE 15
  • 4. Getting the DNA out using alcohol

(DNA Extraction)

  • DNA is separated from the lysis buffer by the addition of

an alcohol (isopropanol).

  • This causes the DNA to “fall out” or precipitate out of the

solution.

  • There’s so much DNA that you can see it and get it on a

stirring rod!

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SLIDE 16

Which is more polar (has more charge)?

+

  • Non-polar region

Polar region

Water (H2O)

+

  • +

Our DNA its surrounded by NaCl or salt and is nonpolar (hydrophobic). It prefers to be in an alcohol solution rather than water.

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THE FUN BEGINS!

THE LAB!

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FIRST, SOME WORDS TO KNOW

Cheesecloth Funnel

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MORE WORDS TO KNOW

Small beakers Test Tube

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WORDS TO KNOW

Stirring Rod Inoculation Loop

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WORDS TO KNOW

Spooling Interface

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WORDS TO KNOW

DNA Extraction Buffer

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SLIDE 23

WHAT YOU WILL NEED

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GET READY - MAKE EXTRACTION BUFFER STEP 1

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STEP 2

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STEP 3

Squeeze, massage and squish gently, mixing for 1 minute.

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STEP 4

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STEP 5

Squeeze, massage and squish gently, mixing for 1 minute.

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STEPS 6 AND 7

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STEP 8

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STEP 9

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STEP 10

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QUESTIONS?

  • WHAT WERE THE QUESTIONS WE POSED AT THE

BEGINNING OF THIS LAB?

  • DID WE ANSWER THEM?
  • MORE QUESTIONS?

IT’S OK TO HAVE MORE QUESTIONS, THAT’S WHAT SCIENCE IS ALL ABOUT!

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QUESTION FOR YOU!

NOW THAT YOU HAVE DNA WHAT IS IT USED FOR?

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SLIDE 35

LOOK AT IT UNDER A MICROSCOPE

Banana DNA stained with toluidine

Image from: http://www.funsci.com/fun3_en/dna/dnaen.htm

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USE PCR TO MAKE LOTS OF COPIES OF A STRING OF SEQUENCES OF DNA

Image from: http://www.openwetware.org/wiki/CH391L/S12/PCR_and_advanced_PCR_techniques

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SLIDE 37

SEQUENCE THE DNA

Image from:https://en.wikipedia.org/wiki/DNA_sequencing Image from: https://en.wikipedia.org/wiki/Genome

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USE IT FOR FORENSICS OR DNA FINGERPRINTING

Image from : http://legacy.hopkinsville.kctcs.edu/instructors/Jason- Arnold/VLI/Module%201/m1DNAfunction/m1DNAfunction_print.html