Nucleic Acids

Nucleic AcidsNucleic Acids

Chemical CompositionChemical Composition

Elements: C, H, O, N, and P.Elements: C, H, O, N, and P.

There are 2 types of nucleic There are 2 types of nucleic acids, deoxyribonucleic acid acids, deoxyribonucleic acid (DNA) and ribonucleic acid (DNA) and ribonucleic acid (RNA).(RNA).

MonomersMonomers

nucleotidesnucleotides, which are made up of , which are made up of threethree parts:parts:

(a) Phosphate (phosphoric acid)(a) Phosphate (phosphoric acid)

(b) N-base (Nitrogenous base)(b) N-base (Nitrogenous base)

(c) Sugar ~ ribose or deoxyribose(c) Sugar ~ ribose or deoxyribose

Nitrogenous bases (N-bases) Nitrogenous bases (N-bases) are:are:

A A – – AAdenine denine (2 Rings =(2 Rings = Purine Purine basebase))

GG – – GGuanineuanine CC – – CCytosineytosine (1 Ring = (1 Ring =

Pyrimidine basePyrimidine base)) TT – – TThyminehymine UU – – UUracilracil

Structure of a NucleotideStructure of a Nucleotide

These are the monomers of nucleic acids. These are the monomers of nucleic acids.

http://trc.ucdavis.edu/biosci10v/bis10v/media/ch09/dna_subunits_adv.html (Animation of N-bases & DNA)

FormationFormation

Formation of a Formation of a nucleic acid polymernucleic acid polymer through through dehydration synthesisdehydration synthesis ((--HH2200).). E.g. DNA or RNAE.g. DNA or RNA

A bond forms between the adjoining A bond forms between the adjoining nucleotides and is assisted by nucleotides and is assisted by polymerpolymerasesases..

A backbone of S-P-S-P-S- etc. is A backbone of S-P-S-P-S- etc. is formed.formed.

Formation Continued!!Formation Continued!!

Formation of Formation of nucleic acid nucleic acid monomersmonomers through through hydrolysishydrolysis ((+H+H2200).).

E.g. NucleotidesE.g. Nucleotides Bonds between the adjacent Bonds between the adjacent

nucleotides are destroyed within nucleotides are destroyed within the nucleic acid polymer.the nucleic acid polymer.

Overall equation:Overall equation:

Dehydration synthesis (-HDehydration synthesis (-H22O)O)

((polymerpolymerasesases))Nucleotide 1 + Nucleotide 2 Nucleotide 1 + Nucleotide 2 nucleic acid + H nucleic acid + H22OO

(RNA or DNA)(RNA or DNA)

Hydrolysis (Hydrolysis (++HH22O)O)

Polymers of nucleic acidsPolymers of nucleic acids

There are two types of nucleic acid There are two types of nucleic acid polymers, polymers, RNARNA and and DNADNA

RNA Structure and FunctionRNA Structure and Function

Found in the nucleus and cytoplasm.Found in the nucleus and cytoplasm. Linear, Linear, single strandsingle strand of nucleotides. of nucleotides. Contains the sugar, Contains the sugar, riboseribose.. N-bases include N-bases include adenineadenine, , uraciluracil, ,

cytosinecytosine and and guanineguanine.. Backbone of Backbone of sugar-phosphatesugar-phosphate. . 3 types of RNA: mRNA (messenger 3 types of RNA: mRNA (messenger

RNA), tRNA (transfer RNA), and rRNA RNA), tRNA (transfer RNA), and rRNA (ribosomal RNA).(ribosomal RNA).

*RNA structure: single-strand moleculeNote: Backbone consists of alternating P-S-P-S-P- etc…

*RNA structure: single-strand moleculeNote: Backbone consists of alternating P-S-P-S-P- etc…

RNA FunctionRNA Function

Helps with Helps with protein protein synthesissynthesis by by mRNA mRNA (messenger (messenger RNA), RNA), tRNAtRNA (transfer RNA), and (transfer RNA), and rRNA rRNA (ribosomal (ribosomal RNA).RNA).

DNA Structure and FunctionDNA Structure and Function

Found in the nucleus, mitochondria Found in the nucleus, mitochondria and chloroplast.and chloroplast.

Consists of a Consists of a double helixdouble helix or or α-α-helixhelix//alpha helix of nucleotides; alpha helix of nucleotides; (looks like a ‘twisted ladder’).(looks like a ‘twisted ladder’).

Contains the sugar, Contains the sugar, deoxyribosedeoxyribose ( 1 ( 1 less oxygen).less oxygen).

N-bases include N-bases include adenineadenine, , thyminethymine, , cytosinecytosine and and guanineguanine..

DNA Structure and FunctionDNA Structure and Function

Complementary base pairingComplementary base pairing of of nucleotides with nucleotides with H-bondsH-bonds (i.e. Purines (i.e. Purines always combine with pyrimidines and always combine with pyrimidines and these matching N-bases are referred these matching N-bases are referred to as to as complementary basescomplementary bases) ) e.g. e.g. AAdenine of one strand is always denine of one strand is always H-H-

bondedbonded to to TThymine on the other; hymine on the other; GGuanine is always paired with uanine is always paired with CCytosine ytosine etc. A – T; T – A; G – C; C – Getc. A – T; T – A; G – C; C – G

Backbone of Backbone of sugar-sugar-phosphatephosphate..

http://www.bbc.co.uk/schools/gcsebitesize/teachers/biology/activities.shtml (Link to DNA)

DNA Structure

DNA has the same backbone as RNA, i.e. alternating P-S-P-S…

http://trc.ucdavis.edu/biosci10v/bis10v/media/ch09/dna_close-up.html(Animation of DNA structure)

Functions of DNAFunctions of DNA Stores genetic information.Stores genetic information.

Maintains growth and repair.Maintains growth and repair.

Controls all cellular activities.Controls all cellular activities.

Contains protein codes.Contains protein codes.

Ensures each daughter cell & gamete Ensures each daughter cell & gamete receives exact genetic information.receives exact genetic information.

DNA RNA

Structure/shape

Double helix or α-helix

Linear, single strand

# of strands

2 1

Sugar Deoxyribose Ribose

N-bases A, T, G, C A, U, G, C

Structural (and functional) Comparison of DNA & RNA

Location in cell

Nucleus & mitochondria

Cytoplasm, nucleus

Functions/roles

-Stores genetic information.-Maintains growth and repair.-Controls all cellular activities.-Contains protein codes.-Ensures each daughter cell & gamete receives exact genetic information.

-Helps with protein synthesis by mRNA (messenger RNA), tRNA (transfer RNA), and rRNA (ribosomal RNA).

DNA RNA

ATP (adenosine ATP (adenosine triphosphate)triphosphate)

A A nucleotidenucleotide with three attached with three attached phosphate groups but phosphate groups but NOTNOT classified classified as a nucleic acid!as a nucleic acid!

It is the “It is the “energy carrier moleculeenergy carrier molecule” ” of cells.of cells.

Functions for the cellFunctions for the cell(ATP) that is…(ATP) that is…

Readily available Readily available source of energysource of energy for:for: Building molecules, transport of Building molecules, transport of

materials in/out of cells, such as active materials in/out of cells, such as active transport, endo/exocytosis, Na+/K+ transport, endo/exocytosis, Na+/K+ pumps, absorption of materials, cell pumps, absorption of materials, cell division, movement, and growth and division, movement, and growth and repair of cells.repair of cells.

All chemical reactions of cells.All chemical reactions of cells.

StructureStructure

ATP consists of 3 ATP consists of 3 parts:parts: Adenine Adenine basebase 5-C sugar 5-C sugar riboseribose 3 phosphate3 phosphate groups groups

You know the drill…name the You know the drill…name the parts…parts…

ATP: Relating the structure ATP: Relating the structure to its role as the “energy to its role as the “energy

currency” of cellscurrency” of cells

ATP is like a “ATP is like a “coin/currencycoin/currency” and ” and when it is required, ATP can be used when it is required, ATP can be used to provide a readily available source to provide a readily available source of energy for synthesis of molecules, of energy for synthesis of molecules, nerve impulses, muscle contraction, nerve impulses, muscle contraction, chemical reactions, transport of chemical reactions, transport of molecules etc.molecules etc.

ATP as “energy currency”ATP as “energy currency”

The high-energy bond of the 3rd phosphate The high-energy bond of the 3rd phosphate group is broken, i.e. hydrolysis and energy group is broken, i.e. hydrolysis and energy is released for the cell to do work! is released for the cell to do work!

ATP ATP energy + ADP + phosphate energy + ADP + phosphate groupgroup

Note: ATP is broken down and removed at a Note: ATP is broken down and removed at a higher rate when metabolic activity higher rate when metabolic activity increases.increases.

RechargingRecharging

ADP is reusable but requires ADP is reusable but requires energyenergy to to reattach the third phosphate group to reattach the third phosphate group to produce another ATP molecule.produce another ATP molecule.

ADP + Phosphate group + energy ADP + Phosphate group + energy ATP ATP

Identify each of the following Identify each of the following chemicalschemicals

And some moreAnd some more

And some more….And some more….

And finally!!! Yes!! Done!!!And finally!!! Yes!! Done!!!