Components of DNA

Nucleic acids where discovered WHEN

1869

Nucleic acids consists of qual parts of WHAT

1. Pentose (5) sugar

2. Nitrogenous base

3. Phosphate

Pentose sugar

• WHAT in RNA 

• WHAT in DNA 

Pentose sugar

• RIBOSE (C5H10O5) - used in RIBONUCLEIC ACIDS in RNA 

• DEOXYRIBOSE (C5H10O5) - used in DEOXYRIBONUCLEIC ACIDS in DNA 

Nitrogenous base

• WHAT

• WHAT

Nitrogenous base

• Purines (DOUBLE ring) - Guanine and adenine

• Pyramides (SINGLE ring) - Uracil, thymine, cytosine

Phosphate (PO4) is found in WHAT

All nucleic acids

In the pentose sugar of DNA and RNA the two sugars only differ in one type of chemical group attached to WHAT carbon 

In the pentose sugar of DNA and RNA the two sugars only differ in one type of chemical group attached to 2’ carbon 

Nitrogenous bases of DNA and RNA:

• DNA uses WHAT

• RNA uses WHAT

Nitrogenous bases of DNA and RNA:

• DNA uses Adenine, guanine, cytosine, thymine

• RNA uses Adenine, guanine, cytosine, uracil

NucleoSIDES: WHAT + WHAT

• The base are bound to the WHAT carbon of sugar

• WHAT are all the new names

NucleoSIDES: Pentose sugar + nitrogenous base

• The base are bound to the 1’ carbon of sugar

• DeoxyADENOSINE, DeoxyGUANOSINE, DeoxyTHYMIDINE, DeoxyCYTIDINE

NucleoTIDES: WHAT + WHAT 

• The phosphates are bound to the WHAT of the sugar 

• Deoxyribonucleotides (dNTP)

NucleoTIDES: NucleoSIDE + Phosphate(s)  

• The phosphates are bound to the 5’ of the sugar 

• Deoxyribonucleotides (dNTP)

DNA: A polymer of WHAT

DNA: A polymer of DEOXIRIBONUCLEOTIDES

Nucleotide monomers polymerize (combine) via WHAT 

Nucleotide monomers polymerize via PHOSPHODIESTERS 

Ester = WHAT

Phosphoester  = WHAT 

Phosphodiester = WHAT 

Ester = C-O-C

Phosphoester = C-O-P 

Phosphodiester = C-O-P-O-C 

The covalent bonds form between the WHAT

The covalent bonds form between the 3’ carbon and this 5’ of adjacent nucleotides

These covalent bonds form the WHAT

These covalent bonds form the PENTOSE-PHOSPHATE BACKBONE

The polynucleotide has WHAT with a WHAT end and a WHAT end 

The polynucleotide has POLARITY with a 5’ end and a 3’ end 

Type of nucleic acid depends on the WHAT in the WHAT

Type of nucleic acid depends on the SUGAR (DNA-deoxyribonucleic acid or RNA - ribose) in the PENTOSE_PHOSPHATE BACKBONE

What charge is aa DNA molecule

Negative

The 5’ end is always attached to WHAT

Phosphate group

The 3-D structure of DNA is based on the three chemical components of DNA, scientists knew that DNA:

• Was WHAT 

• Had a WHAT 

• The WHAT in the nucleotide “WHAT”

The 3-D structure of DNA is based on the three chemical components of DNA, scientists knew that DNA:

• Was RELATIVELY LINEAR 

• Had a PENTOSE PHOSPHATE BACKBONE 

• The NITROGENOUS BASES in the nucleotide “HELD THE CODE”

Chargaff analyzed overall WHAT of the four WHAT in various species

Chargaff analyzed overall QUANTITIES of the four NITROGENOUS BASES in various species

What is chargaff rule: WHAT

other conclusion:

1. WHAT 

2. WHAT 

3. WHAT 

What is chargaff rule: %A = %T and %C = %G

other conclusion:

1. %Purines (A+G) = % Pyrimidine (C+D)  

2. C+G wont = A+T  

3. A, C, G, and T are NOT present in EQUAL amounts  

X-ray diffraction studies:

• DNA molecules were WHAT and about WHAT in diameter 

• 0.34nm periodicity suggested that bases were stacked like pennies on top of one another 

• WHAT pattern suggested WHAT 

• Franklin did not propose a WHAT 

• Wilikins (franklins colleague) shoes images Watson

X-ray diffraction studies:

• DNA molecules were CYLINDRICAL and about 2nm in diameter 

• 0.34nm periodicity suggested that bases were stacked like pennies on top of one another 

• X-SHAPES pattern suggested HELIX 

• Franklin did not propose a DEFINITIVE MODEL 

• Wilikins (franklins colleague) shoes images Watson

DNA double helix:

• Base pairing is WHAT and therefore, base pair sequence on one strand can be used to specify the WHAT of the other strand 

• Base pairs are stacked WHAT to the axis and contributes to WHAT of the double helix 

• WHAT between bases keeps two strands together:

         — A-T pairs share HOW MANY H-bonds

         —  G-C pairs share HOW MANY H-bonds

DNA double helix:

• Base pairing is COMPLEMENTARY and therefore, base pair sequence on one strand can be used to specify the SEQUENCE of the other strand 

• Base pairs are stacked FLAT LYING PERPENDICULAR to the axis and contributes to STABILITY of the double helix 

• WHAT between bases keeps two strands together:

         — A-T pairs share 2 H-bonds

         —  G-C pairs share 3 H-bonds

The double helix can be WHAT (separated or change shape of DNA)

The double helix can be DENATURES (separated or change shape of DNA)

WHAT of single strands of DNA and RNA by forming H-bonds

• WHAT-WHAT

• WHAT-WHAT hybrids are possible

ANNEALING of single strands of DNA and RNA by forming H-bonds

• DNA-DNA

• DNA-RNA hybrids are possible

Nucleic acid hybridization highly-specific (two strands must be WHAT in sequence), WHAT-driven and WHAT-dependent

Nucleic acid hybridization highly-specific (two strands must be COMPLEMENTARY in sequence), TEMPERATURE-driven and CONCENTRATION-dependent

DNA-RNA hybrids are important in WHAT, WHAT and reproduction of some WHAT

DNA-RNA hybrids are important in DNA REPLICATION, TRANSCRIPTION and reproduction of some RNA VIRUSES

Watson and Cricks model of DNA replication:

• WHAT allows WHAT (original strand) to act as WHAT

• Parental strands can unwind by breaking the WHAT between bases

• WHAT (conserved since half of the original strand is still present) where the double helix will contain. aWHAT and a WHAT (daughter) strand

Watson and Cricks model of DNA replication:

• COMPLEMENTARY BASE PAIRING allows PARENTAL STRANDS (original strand) to act as TEMPLATE for DNA REPLICATION

• Parental strands can unwind by breaking the HYDROGEN BONDS between bases

• SEMICONSERVATIVE REPLICATION (conserved since half of the original strand is still present) where the double helix will contain. a PARENTAL STRAND and a NEWLY SYNTHESIZED (daughter) strand

Eukaryotes have WHAT enclosed in a nucleus

Eukaryotes have MULTIPLE LINEAR DNA MOLECULES enclosed in a nucleus

Organization in Eukaryotes:

To keep the DNA organized, and help regulate gene expression, DNA is condensed into WHAT

To keep the DNA organized, and help regulate gene expression, DNA is condensed into CHROMATIN (normal state of DNA) 

Organization in Eukaryotes:

Before DNA is in chromatin form, the DNA double helix if first wrapped TWICE(ish) around WHAT to form a WHAT 

Before DNA is in chromatin form, the DNA double helix if first wrapped TWICE(ish) around HISTONE PROTEIN to form a NUCLEOSOME (to make chromatin)  

Organization in Eukaryotes:

Each DNA molecule is a repeating series of WHAT, called WHAT, that looks like “beads on a string” under an electron microscope 

Organization in Eukaryotes:

Each DNA molecule is a repeating series of NUCLEOSOMES, called 10nm CHROMATIN FIBRES, that looks like “beads on a string” under an electron microscope 

Organization in Eukaryotes:

Additionally histones (H1) cause the chromatin to coil further into WHAT 

Organization in Eukaryotes:

Additionally histones (H1) cause the chromatin to coil further into 30nm CHROMATIN FIBRES (solenoids)  

Organization in Eukaryotes:

Chromatin is the “WHAT” state if our DNA molecules 

Organization in Eukaryotes:

Chromatin is the “NORMAL” state if our DNA molecules 

Organization in Eukaryotes:

The chromatin unwinds (expresses the double helix) during WHAT and WHAT 

Organization in Eukaryotes:

The chromatin unwinds (expresses the double helix) during DNA REPLICATION and TRANSCRIPTION  

Organization in Eukaryotes:

The chromatin than condenses further into WHAT - during WHAT and WHAT

Organization in Eukaryotes:

The chromatin than condenses further into CHROMOSOMES (Highly condensed state of DNA molecules)  - during MITOSIS and MEIOSIS

Histones are basic, WHAT charged proteins

Histones are basic, POSITIVELY charged proteins

The nucleosome is a WHAT with about HOW MANY base pairs of DNA wrapped around it

The nucleosome is a HISTONE OCTAMER with about 147 base pairs of DNA wrapped around it

Histone (H1) binds WHAT and coils nucleosomes to from WHAT

Histone (H1) binds LINKER DNA and coils nucleosomes to from 30nm CHROMATIN FIBRE

DNA packing along the double helix is not WHAT

DNA packing along the double helix is not UNIFROM

Euchromatin regions have lower WHAT and genes are WHAT

Euchromatin regions have lower DNA COMPACTION and genes are ACTIVELY EXPRESSED

Heterochromatin are chromosomal regions of WHAT where gene expression WHAT

Heterochromatin are chromosomal regions of HIGH DNA COMPACTION where gene expression is CONSTITUTIVE or FACULTATIVE 

Constitutive (always) heterochromatin

DNA is ALWAYS highly compacted (centromeres and sub-telomeric regions) 

Facultative (sometimes) heterochromatin

Can switch to EUCHROMATIN depending on cell type and during cell development 

Chromosome organization:

1. Chromosomes are the WHAT from of DNA 

2. Chromosomes structure WHAT DNA from WHAT

3. Chromosomes can be WHAT easily and transmitted to each WHAT during WHAT

Chromosome organization:

1. Chromosomes are the FULLY COMPACTED from of DNA 

2. Chromosomes structure PROTECTS DNA from DAMAGE

3. Chromosomes can be SEPARATED easily and transmitted to each DAUGHTER CELL during CELL DIVISION

Chromosomes need to be fully WHAT (DNA WHAT) and properly transmitted to each WHAT during WHAT 

Chromosomes need to be fully DUPLICATED (DNA REPLICATION) and properly transmitted to each DAUGHTER CELL during MITOSIS and MEIOSIS 

1. Origins of replication 

Multiple DNA sequences along chromosomes which INITIATE DNA REPLICATION 

2. Centromere

DNA sequences required for correct segregation of chromosomes 

3. Telomeres

DNA sequences located at the ENDS OF THE CHROMOSOME that prevents degradation and allow proper replication

Majority of eukaryotic cells are WHAT (two copies of each WHAT chromosome) 

Majority of eukaryotic cells are DIPLOID (two copies of each HOMOLOGOUS chromosome) 

Only sexually-reproductive cells (sperm and ova) have a WHAT genome 

Only sexually-reproductive cells (sperm and ova) have a HAPLOID genome 

Some eukaryotes are WHAT (more than a pair of each chromosome) such as large WHAT and WHAT 

• Triploid = WHAT 

• Tetraploid = WHAT 

Some eukaryotes are POLYPLOID (more than a pair of each chromosome) such as large PROTISTS and FLOWERING PLANTS  

• Triploid = 3 copies  

• Tetraploid = 4 copies

DNA organization is PROKARYOTES:

Prokaryotes typically have a WHAT DNA molecule found in the WHAT (no WHAT) 

DNA organization is PROKARYOTES:

Prokaryotes typically have a SINGLE, DOUBLE-STRANDED CIRCULAR DNA molecule found in the CYTOSOL (no NUCLEUS) 

DNA organization is PROKARYOTES:

Prokaryotic DNA does not need the same level of WHAT as eukaryotic DNA (because they are WHAT) 

DNA organization is PROKARYOTES:

Prokaryotic DNA does not need the same level of COMPACTION as eukaryotic DNA (because they are CIRCULAR) 

DNA organization is PROKARYOTES:

They use WHAT, also called WHAT (no WHAT)

DNA organization is PROKARYOTES:

They use HISTONE-LIKE PROTEINS (HLPs) , also called NUCLEOID-ASSOCIATED PROTEINS (NAPs)  (no HISTONE)

DNA organization is PROKARYOTES:

Prokaryotes also have other small independent double-stranded circular DNA molecules called WHAT 

DNA organization is PROKARYOTES:

Prokaryotes also have other small independent double-stranded circular DNA molecules called PLASMIDS 

DNA organization is PROKARYOTES:

Each cell can have multiple different WHAT, as well as multiple WHAT of each plasmid 

DNA organization is PROKARYOTES:

Each cell can have multiple different PLASMIDS (small DNA molecules), as well as multiple COPIES of each plasmid 

DNA organization is PROKARYOTES:

Plasmids can carry a few WHAT (1-10) - none WHAT 

DNA organization is PROKARYOTES:

Plasmids can carry a few GENES (1-10) - none ESSENTIAL for life  

DNA organization is PROKARYOTES:

Plasmids carry “WHAT” WHAT that give them an advantage in some environments

Such as

• Metabolism of WHAT

• WHAT (ability to cause disease)

• WHAT

DNA organization is PROKARYOTES:

Plasmids carry “BONUS” GENE that give them an advantage in some environments

Such as

• Metabolism of RARE CARBON SOURCE

• VIRULENCE (ability to cause disease)

• ANTIBIOTIC RESISTANCE 

Uracil structure

• Single (pyrimidines)

• Only H

Thymine structure 

• Single (pyrimidines) 

• CH3 group 

Cytosine structure

• Single (pyrimidines)

• NH2 group

Adenine structure

• Double (Purine)

• No double bond O

Guanine structure

• Double (purine)

• Double bond O