1 DNA Structure.ppt

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UNIT 3 Genetics and Biotech

• _{Bio 30 GB2 Investigate how genetic information}

is stored, transmitted and expressed at the molecular level.

• _{Bio 30 GB1 Explore classical (i.e. Medelian)}

and current(i.e. chromosomal) understandings of biological inheritance.

• _{Bio 30 GB3 Explore the impacts of historical,}

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DNA

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DNA

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Oswald Avery

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Erwin Chargaff

• _{Chargaff discovered that DNA has the same amount of} adenosine as thymine and the same amount of cytosine as guanine. A = T and G = C

A AA AA A A

T T T

T T T T

C C

C G G

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Rosalind Franklin &

Maurice Wilkins

• _{Franklin and Wilkins} used x-ray to

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Watson and Crick

They credited Wilkins and Franklin. Wilkins also got a Nobel Prize but Franklin did not. Rosalind had passed away and the Nobels are not awarded

posthumously.

•

_{Watson & Crick won a Nobel Prize for}

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DNA is a Nucleic Acid

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•

_{Nucleic acids contain C,}

H, N, O, P

•

_{Are made up of}

nucleotide monomers

•

_{Store genetic}

information

•

_{Help make proteins}

•

_{Examples: DNA & RNA}

sugar phosphate

nitrogen base

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DNA Structure

phosphate nucleotide N base PO₄ Sugar Sugar PO₄ N base The numbers are the positions of the carbons on the sugar.

(the 3’ end)

5

4

3 2

1

(the 5’ end)

sugar

nitrogen base

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A NUCLEOTIDE

H H₂ H H H₃ H H H H H O O O C C C N N P O O O C C C C C O O O C C 1. 2. 3. 1. 2. 3.

1. Phosphate Group

2. 5-Carbon Sugar

(Dexoyribose or Ribose)

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Nucleotides

• _{There are four nitrogen bases making up four different} nucleotides.

Adenine

Guanine

Thymine

Cytosine

Pyrimidines

Purines

A

C

G

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Chargaff’s Base Pair Rules

• _{Adenine always bonds with thymine.} • _{Adenine (A) to Thymine (T)}

• _{Guanine always bonds with Cytosine.} • _{Guanine (G) to Cytosine (C)}

The lines between the bases represent hydrogen bonds

A

C

G

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C G

A A T

G

Nucleotide P _S N-b

Pairing DNA Nucleotides

Rule A to

C to T

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What is RNA?

•

_RNA

_{stands for}

_R

_ibo

N

ucleic

A

cid

•

_{RNA is DNA’s “helper”}

molecule.

•

_{RNA is a single stranded}

nucleic acid

•

_{Made up of monomers}

called

nucleotides

sugar phosphate

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A

B

C

RNA Nucleotides

• _{A -}_{Sugar (ribose)} • _{B -}_Phosphate

• _{C -}_{Nitrogen base}

sugar

phosphate

nitrogen base

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Phosphate Group

Nitrogen Base

Sugar

(ribose)

RNA

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Rules for Base Pairing

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_{Cytosine pairs with Guanine}

•

_{Adenine pairs with Uracil}

Notice that RNA has

Uracil

(not thymine)

A = U

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Rules for Base Pairing

•

C = G

•

A = U

3’ DNA strand

5’ DNA strand RNA strand

C

A

T G

G

U

C

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What is the function of RNA?

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_{Carries DNA’s message code}

•

_{Helps make protein}

•

_{Types of RNA}

•

_{Messenger RNA (mRNA)}

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Transfer RNA (tRNA)

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DNA RNA

Sugar is deoxyribose

Sugar is ribose

Adenine base is present

Cytosine base is present

√

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DNA RNA

Guanine base is present

Thymine base is present

Uracil base is present

Shape is double helix

√

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DNA RNA

Shape is single stranded

Located in nucleus

Located in cytoplasm

Stores genetic information

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_√

√

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DNA RNA

Functions in protein synthesis

Composed of nucleotides

Template for synthesis of

proteins

Transcribes the Template

More than one type

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https://www.youtube.com/watch?v=NNASRkIU5Fw&t=5s