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Explain DNA Extraction

In this worksheet, students will explain what molecular components that make up the DNA our cells use to sustain life and reproduce, looking at key definitions and explaining the structure of DNA.

'Explain DNA Extraction' worksheet

Key stage:  KS 4

GCSE Subjects:   Biology: Single Subject, Biology: Combined Science

GCSE Boards:   Pearson Edexcel

Curriculum topic:   Natural Selection and Genetic Modification

Curriculum subtopic:   Natural Selection and Genetic Modification

Difficulty level:  

Worksheet Overview

QUESTION 1 of 10

DNA is what all genetic information is made up of.

 

It's stored in cell nuclei, and is a long chain of tightly wound-up coded instructions which cells unravel, read and use to make proteins.

 

When cells want to make a specific protein, they read DNA in small chunks at a time, called a gene.

 

All this genetic information in us is called our GENOME!

 

 

DNA is also a polymer of many nucleotides- a group made of a phosphate group on a sugar attached to a nitrogenous base, linking into two strands to make the double helix.

 

There are 4 different bases, A, T, C, G, and they’re very specific about who they pair with:

 

Adenine with Thymine and Cytosine with Guanine

 

 

 These groups are COMPLEMENTARY base pairs, and they are joined by weak hydrogen bonds- this is how we get the runs going through the double helix ladder!

 

To pull the double helix together, nucleotides on the SAME side link their phosphate groups and sugars together vertically to make the ‘sugar-phosphate backbone’.

 

 

 

EXPERIMENT TIME!

 

 Knowing about DNA means scientists can play around with it too, like taking a piece of DNA out of fruit cells!

Let’s use a banana:

 

1. Take a peeled banana and mush it

2. Add a tsp of salt and a bit of washing up liquid

3. Heat at 60°c GENTLY for 5 minutes

4. Filter the mix and only keep THE LIQUID

5. Cool in an ice bath and then carefully pour cold ethanol on top of it

And voilà! You should see bits of DNA with bubbles in them where the banana and ethanol meet!

 

 

But, you got me, it’s not bananas scientists really care about: it’s Genetic Profiling!

 

In our genomes, there are combinations of DNA that are very specific to us that can be used as a passport.

 

If we use what we know to extract small bits of unique DNA from humans, we can make a unique profile of DNA bands for every person.

 

This method is a lifesaver because it has helped us determine paternity, by comparing DNA between parents and the baby, and even to solve crime!

Put these terms into size order, starting with the largest:

 

Column A

Column B

1. (Largest)
Genome
2.
Nucleotide
3.
Base
4.
Nucleus
5. (Smallest)
Gene

What is the name of the spiral form DNA takes?

 

There are 4 bases, 3 of which are Adenine, Thymine and Cytosine. The fourth is called...?

Which of these possible combinations of DNA bases (Adenine, Guanine, Cytosine and Thymine) are correct?

In this picture of a double helix, what does the orange swirl represent?

 

 

[Choose ONE option below]

Sugar Molecules Only

Bases Only

Sugar Molecules and Bases

Sugar molecules and phosphate groups

Phosphate Groups Only

Label the picture of the nucleotides below: 

 

Sugar Molecules Only

Bases Only

Sugar Molecules and Bases

Sugar molecules and phosphate groups

Phosphate Groups Only

If you were to extract DNA from a kiwi, how would you go about it?

 

 

Column A

Column B

1.
Add cold ethanol on top of the mix
2.
Cool the solution a water bath
3.
Peel and mash up the kiwi
4.
Filter the concoction and KEEP THE LIQUID only
5.
Add a little salt and some washing up liquid to th...
6.
Heat the mixture gently for 5 mins

DNA is a polymer because it is made of many small units called?

What is one of the key ways DNA extraction is used in science?

A person's genome is what?

All the genetic information in our bodies

All the genetic information in one cell

All the genetic information in a section of DNA

  • Question 1

Put these terms into size order, starting with the largest:

 

CORRECT ANSWER

Column A

Column B

1. (Largest)
Nucleus
2.
Genome
3.
Gene
4.
Nucleotide
5. (Smallest)
Base
EDDIE SAYS
So there's a lot being asked here but I hope your understanding of how DNA is organised helped make this question easier to answer! The largest term here is the nucleus, which acts as the cell's storage house of DNA. All these other terms refer to zooming in on the DNA in the nucleus more and more closely, the entire bunch of genetic information being our genome, which in the nucleus is arranged in chromosomes. When a chromosome is unravelled, a piece of the double helix is a gene, but in the most basic form, DNA is made of blocks of nucleotides that make up the double helix, and one piece of a nucleotide is a base.
  • Question 2

What is the name of the spiral form DNA takes?

 

CORRECT ANSWER
DOUBLE HELIX
A DOUBLE HELIX
THE DOUBLE HELIX
EDDIE SAYS
The term we use to describe the spiral shape we connect with DNA is the double helix, pieced together vertically and horizontally by nucleotides bonded together.
  • Question 3

There are 4 bases, 3 of which are Adenine, Thymine and Cytosine. The fourth is called...?

CORRECT ANSWER
Guanine
G
EDDIE SAYS
The four bases are Guanine, Adenine, Thymine and Cytosine, or G, A, T and C
  • Question 4

Which of these possible combinations of DNA bases (Adenine, Guanine, Cytosine and Thymine) are correct?

CORRECT ANSWER
EDDIE SAYS
When the bases hydrogen bond in the center of the double helix, Adenine can only join to Thymine, and Cytosine can only join to Guanine. However, the initials can be switched around, for example both CG and GC are acceptable, as are TA and AT.
  • Question 5

In this picture of a double helix, what does the orange swirl represent?

 

 

[Choose ONE option below]

CORRECT ANSWER
Sugar molecules and phosphate groups
EDDIE SAYS
The outside of the double helix is the sugar-phosphate backbone, made of linked phosphate and sugar groups shared between a vertical pair of nucleotides on the same side.
  • Question 6

Label the picture of the nucleotides below: 

 

CORRECT ANSWER
EDDIE SAYS
The arrangement of a nucleotide is important because how it bonds gives DNA it\'s double helix shape. On the outside is a phosphate group, which is linked to a corner of a 5 sided sugar called a pentose sugar. The sugar then bonds to a base- depending on the nucleotide, this could be A, T, C or G, which then sticks out into the middle of the double helix, waiting to hydrogen bond to a base from a nucleotide from the opposite strand!
  • Question 7

If you were to extract DNA from a kiwi, how would you go about it?

 

 

CORRECT ANSWER

Column A

Column B

1.
Peel and mash up the kiwi
2.
Add a little salt and some washin...
3.
Heat the mixture gently for 5 min...
4.
Filter the concoction and KEEP TH...
5.
Cool the solution a water bath
6.
Add cold ethanol on top of the mi...
EDDIE SAYS
DNA extraction is a very helpful concept and maybe an experiment you\'ve already tried at school! You could be asked to design an experiment like this so it\'s important to know the key steps. If you do all the steps above correctly, you should be able to see fragments of DNA where the ethanol and mixture meets.
  • Question 8

DNA is a polymer because it is made of many small units called?

CORRECT ANSWER
NUCLEOTIDES
EDDIE SAYS
How did you find this question? The smallest form of DNA if its nucleotides- little building blocks that bond together to form the iconic DNA spiral shape.
  • Question 9

What is one of the key ways DNA extraction is used in science?

CORRECT ANSWER
GENETIC PROFILING
EDDIE SAYS
Learning how to extract DNA is not propelled by a fruit obsession! Removing small fragments of personally unique DNA from humans has allowed us to create genetic profiles for people, letting us identify people in situations like paternity testing or crimes!
  • Question 10

A person's genome is what?

CORRECT ANSWER
All the genetic information in our bodies
EDDIE SAYS
Our genome is EVERYTHING ABOUT US! It\'s the entire collection of DNA is our bodies and the cells that have a nucleus store this info!
---- OR ----

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