Nucleic Acids & The RNA world

A new bond forms between 3'C of a sugar molecule and the 5' phosphate of the incoming nucleotide and H20 is released as a byproduct.

Lone Nucleotide (pt.2)

Adenine (A) Guanine (G) 2 STRING purine structural group, Cytosine (C) Uracil (U) Thymine (T) from the single-ring pyramidine group

Nitrogenous Bases

A polymer of nucleotides, each nucleotide is a phosphate group bonded to a 5 carbon sugar, on its other side the sugar bonds to a nitrogenous base

Nucleic Acid

DNA

Polymer

Larger than pyrimidines & contain a 2 carbon nitrogen rings. Guanine (G) & Adenine (A)

Purines

Phosphate group, 5 carbon sugar, nitrogenous base bonded to 1 carbonate sugar

The General Structure of a Nucleotide

1.Proteins 2.NucleicAcid (DNA/RNA) 3.Carbohydrates (sugars) 4.Lipids (fats)

The Macromolecules of Life

Which components of the nucleotide are involved?

This results in a phosphodiester bond which occurs between the 5' phosphate on the incoming nucleotide and the 3' that it is waiting to grow.

They create the nucleic acids primary structure, which is written out from 5' to 3' end (the direction in which cells make RNA and DNA) using the first letter of each nucleotide.

What do the nucleotide base sequences create?

Yes, sugar phosphate linkages form a "backbone" of a nucleic acid; this hair is directional because one of the ends has unlinked 5' carbon- bound phosphate group and the other end has an unlinked 3' carbon hydroxyl group. (figure 4.3)

nAre DNA & RNA strands directional?

Both nucleic acids and proteins have a backbone formed from condensation reactions.

Backbone

1. How are bases classified? Which bases are classified as purines? Which bases are classified as pyrimidines? How do purines and pyrimidines differ (structurally)?

Bases are classified by either being a pyrimidine or purine. Pyrimidines are smaller than purines and contain 1 carbon ring while purines contain 2 carbon nitrogen rings. Guanine and Adenine are purines and Cytosine, Uracil, and Thymine are pyrimidines.

Linus Paling

Came up with a model of DNA that did not work which helped push what would work.

The key step in the evolution of life is the formation of self replicating molecules. Chance errors in the molecules copy making created variations - natural selection.

Chemical Evolution

What type of chemical reaction results in individual nucleotide monomers being fused together to form a DNA polymer?

Condensation reaction

Lab simulations of chemical evolution have not yet produced complete nuceotides, but sugars and nitrogenous bases are easily made.

Could chemical evolution result in the production of nucleotides?

A complex molecule containing the genetic information that makes up the chromosomes.

DNA

C,T,A,G

DNA Bases

Respiratory of genetic info

DNA Function:

is due to to hydrogen bonding between nitrogenous bases that extend off the nucleic acid backbone

DNA Secondary Structure

Double Helix

DNA Structure

Deoxyribose

DNA Sugar

A chain of nucleic acids is directional. -One end has a 5' unlinked phosphate group -Other end has a 3' unlinked hydroxyl group Sequence written in 5' to 3' direction EX: 5' ATG CCT GGG CCT ATC 3'

DNA strands

Contain deoxyribose and are the monomers for DNA

Deoxyribonucleotides

1. A 5 carbon sugar (hub of nucleotides) 2. A phosphate group 3. A nitrogenous base

3 Major Components of Nucleotide Monomer

What RNA sequence would be produced if the following DNA sequence were used as a template: 5'- AGC TTA CCC ACG -3' . Be sure to correctly label each end.

3' UCG AAU GGG UGC 5'

Ribose & Deoxyribose but D has an H instead of an -OH on its 2 carbon

5 Carbon sugarS?

Found in both types of nucleotides

Adenine (A) Guanine (G) Cytosine (C)

What type of bonds join together the nitrogenous bases of 2 different DNA strands? (In other words, what type of bonds connects two complementary bases?)

Adenine pairs with Thymine forming 2 H bonds while Cytosine pairs with Guanine forming three H bonds.

DNA strands run in opposite directions for an upright DNA double helix. Top of strand 5' running down to 3'

Antiparallel

Discovered base pairing * Stated that in DNA, THE # of purines = the number of pyrimidines the # of Ts and As are equal. and the # of Cs and Gs are equal.

Erwin Chargaff

Nucleic acids (polymers) form when nucleotides join together via condensation reactions (release H20 as a byproduct) This results in a phosphodiester bond between the 5' phosphate group on the incoming nucleotide and the 3' Carbon on the other nucleotide.

How do nucleotides polymerize to form nucleic acids?

Rules: A always pairs with T (or U in RNA) C always pairs with G

How does the structure of the nitrogenous bases relate to the "base pairing" rules?

Discovered DNA'S secondary structure in 1953. Their model built on the following results from other labs. -They knew that DNA had a sugar phosphate backbone Conclusion: 2 antiparallel DNA strands form a double helix

James Watson & Francis Crick

James Watson & Francis Crick, Rosalind Franklin & Maurice Wilkins, Erwin Chargaff, Linus Pauling. hhmi.org/biointeractive/double-helix

Know the contributions these scientists discovery of the DNA structure

Contains sugar, phosphate, and a nitrogenous base

Lone Nucleotide

5 carbon sugar (red/brown) + phosphate group (yellow) + nitrogenous base (green) = a nucleotide

Nucleotide

DNA & RNA are nucleic acid polymers made up of monomers called nucleotides

Nucleotides & Monomers

Polymerization requires an energy source. In cells enzymes catalize nucleotide Polymerization, but first two extra phosphate groups are added to each nucleotide to rise their potential energy and "activate" them.

Polymerization

Guanine pairs with Cyosine (by 3 H bonds) Adenine pairs with Thymine (by 2 H bonds) Key: Hydrogen Bonds link together bases

Purines pair with Pyrmidines

Smaller than purines, contain 1 carbon nitrogen ring Uracil (U) in RNA & Thymine (T) in DNA & Cytosine (C)

Pyrimidines

The first cell replicator A type of nucleic acid consisting of nucleotide monomers with a ribose sugar and the nitrogenous bases adenine (A), cytosine (C), guanine (G), and uracil (U); usually single-stranded; functions in protein synthesis and as the genome of some viruses.

RNA

C, U, A,G

RNA Bases

Involved in protein synthesis & gene regulation: carrier of genetic info in some viruses

RNA Function

Usually single stranded -Allows it to both carry info & catalyze chemical reactions -Similar to DNA but ribose is the sugar in the sugar phosphate backbone -Contains uracil not thymine -Hydroxyl group on ribose 2' carbon making it more active & less stable

RNA Structure

Ribose

RNA Sugar

They contain ribose and are the monomers that join to make RNA.

Ribonucleotides

They showed the double helix from photo 51. * Use DNA x-RAY crystallography to calculate distance between atom groups that regularly repeated -Concluded that the structure of DNA was either helical or spiral

Rosalind Franklin & Maurice Wilkins

Repel each other, giving these "activated" molecules high potential energy. This stored energy is released when the phosphate forms new bonds.

The Negative charges of linked phosphates

Condensation reaction & formation of a covalent PHOSPHODIESTER BOND

What does a lone nucleotide lead to?

Deoxyribonucleotides

Where is Thythime located?

Ribonucleotides

Where is Uracil located?

List at least 2 structural differences between DNA and RNA

a. RNA has a hydroxyl group bonded to 3 prime and 2 prime while DNA has OH bonded to 3 prime and H bonded 2 prime. b. DNA has adenine and thymine while RNA has adenine and uracil