Warm up

A. Who suggested that DNA has spiral shape.

B. Who presented the DNA model in 1953 at Cambridge University, London. The Nobel Prize was awarded for presenting this DNA model.

Rosalind Franklin James Watson and Francis Crick

DNA STRUCTURE (REVIEW)

By Mrs Kasturey

and Mrs Rose

Complete DNA-R-US

worksheet as we go

through PPT

3

A double-stranded nucleic acid that

contains the genetic information for cell

growth, division, and function

4 DNADeoxyribonucleic Acid

1. DNA stands for

___________________________ _________

and is the basic substance of heredity.

DNA is a set of _____________ for

building your body and controls

everything about the way you

____ and __________.

What is DNA?

DNA is a set of

instructions for building

your body and controls

everything about the

way you look and

function.

Double-helix

3. A DNA _________ looks like a twisted

ladder. Because of its shape, a DNA

molecule is often called a “_______

________”. A helix is shape that twist.

A DNA _molecule_ looks like a twisted

ladder. Because of its shape, a DNA

molecule is often called a “_double_

_helix_”. A helix is shape that twist.

4. The DNA double helix looks like a twisted ladder.

The side of the ladder, the hand railing, are made

of ___________________ and _____________.

The DNA double helix looks

like a twisted ladder. The

side of the ladder, the hand

railing, are made of _sugar

molecule and

_phosphate_.

Side railings

5. The rungs of the ladder are formed by pairs of

___________________________.

The rungs of the

ladder are formed

by pairs of

__Nitrogen bases.

Nitrogen Bases

6. Nitrogen bases are molecules that contain the

element ______________ and other element.

Nitrogen bases

are molecules

that contain the

element

__Nitrogen and

other element.

7. The two sides of DNA ladder are made up of

molecules of a sugar called

__________________, alternating with the

molecules known as ________________.

The two sides of DNA ladder are made up of

molecules of a sugar called _deoxyribose_,

alternating with the molecules known as

_phosphates.

Back bone

8. There are four types of nitrogen bases:

a. (ad uh neen) ________________.

b. (thy meen) _________________.

c. (gwah neen) ________________.

d. (sy tuh seen) ________________.

There are four types of nitrogen bases:

a. (ad uh neen) ________________.

b. (thy meen) _________________.

c. (gwah neen) ________________.

d. (sy tuh seen) ________________.

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9. Adenine always pair with ________________;

and Guanine always pair with ______________.

Adenine always

pair with

_Thymine; and

Guanine always

pair with

_Cytosine.

Base pair pairing

DNA-R-Us

DNA DNA

guanine G Cytosine

Thymin-T Adenine

adenine A Thymin

cytosine C Guanine

10. The pairing pattern is the key to

understanding how DNA _________ occurs.

The pairing pattern is the

key to understanding

how DNA _replication_

occurs.

Replication

11. So if one side of DNA

ladder has –

Then the other side will be –

Making the complete

structure –

OR in simple letters – C A A G

G T T C

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Now your turn to try –

Simply write the matching base pair.

NO NEED TO DRAW the other side.

Practice