Structure of DNA

The structure of the molecule of inheritance must allow the following properties

1. Must permit accurate and fast WHAT

2. Must be able to WHAT ‘WHAT’ in some way

3. Must be able to WHAT or WHAT at a level consistent with the WHAT between the individuals observed

The structure of the molecule of inheritance must allow the following properties

1. Must permit accurate and fast REPLICATION

2. Must be able to ENCODE ‘INFORMATION’ in some way

3. Must be able to MUTATE or CHANGE at a level consistent with the VARIATION between the individuals observed

DNA is made up of NUCLEOTIDES

DNA is made up of NUCLEOTIDES

What is a nucleotide made up of for DNA

1. WHAT

2. WHAT

3. WHAT

What is a nucleotide made up of for DNA

1. Deoxyribose sugar (5 carbon)

2. Phosphate group

3. Base (nucleic acid)

What are the two types of nucleic acids

1. WHAT

2. WHAT

What are the two types of nucleic acids

1. Purines

2. Pyrimidines

purines

2 rings

Pyrimidines

1 ring

what bases are in purines

• Adinine

• Guanine

what bases are in pyrimidine

• Thymine

• Cytosine

(all have a Y in the name)

Chargaff’s rules in DNA

• Number of purines WHAT the number of pyrimidines

• Amount of A WHAT T, G WHAT C

• Amount of A+T WHAT G+C

Chargaff’s rules in DNA

• Number of purines EQUALS the number of pyrimidines

• Amount of A EQUALS T, G EQUALS C

• Amount of A+T DOESN’T EQUAL G+C

X-ray diffraction images proved that DNA is a WHAT

X-ray diffraction images proved that DNA is a DOUBLE HELIX

• Watson and Crick determined that purines had to WHAT with pyrimidines

• Based on Chargaff’s rules, they proposed that A always paired with WHAT and G always paired with WHAT

• Watson and Crick determined that purines had to PAIR with pyrimidines

• Based on Chargaff’s rules, they proposed that A always paired with T and G always paired with C

The structure of DNA is WHAT, meaning there is a WHAT groove and a WHAT groove

The structure of DNA is ASYMMETRICAL, meaning there is a MAJOR groove and a MINOR groove

The backbone of DNA is held up by WHAT = WHAT bonds

The backbone of DNA is held up by PHOSPHODIESTER LINKAGE = COVALENT bonds

The two strands of DNA are WHAT which is they they are capable of WHAT

The two strands of DNA are COMPLEMENTARY which is they they are capable of REPLICATING

Adenine and thymine = HOW MANY hydrogen bonds

Guanine and cytosine = HOW MANY hydrogen bonds

Adenine and thymine = 2 hydrogen bonds

Guanine and cytosine = 3 hydrogen bonds

The DNA strands are WHAT

The DNA strands are ANTIPARALLEL

The OH end of the strand is the WHAT end and the phosphorous end is the WHAT end

The OH end of the strand is the 3’ end and the phosphorous end is the 5’ end

The diameter of a double helix is WHATÅ, and the width of 10 base pairs is WHATÅ; therefore, the distance between base pairs is WHATÅ

The diameter of a double helix is 20Å, and the width of 10 base pairs is 34Å; therefore, the distance between base pairs is 3.4Å