NUCLEIC ACIDS

- DNA is a polynucleotide, usually double stranded, made up of nucleotides with bases A,T,C and G.- RNA is a polynucleotide, usually single stranded made up of nucleotides containing the bases A,U,C and G.

Objective:describe the structure of RNA and DNA and explain the importance of base pairing and hydrogen bonding

CENTRAL DOGMA OF BIOLOGY

HOMEWORK:

Devise and complete a table of key roles for each specified ion – information coming from bibliographic and web-based research

in living organisms: calcium, sodium, potassium, magnesium, chloride, nitrate, phosphate

NUCLEIC ACIDS

They come in two forms:

1) DNA (deoxyribonucleic acid)2) RNA (Ribonucleic acid)

DNA in eukaryotic cells are found in the nucleus, acting as a information store.

CONTINUED…

Nucleic acids are composed of monomers called a nucleotide.

A nucleotide is composed of 3 subunits:

One phosphate group;One sugar molecule ;One organic nitrogenous base.

These subunits are joined by covalent bonds to form a nucleotide molecule.

BASE TYPES

FEATURES OF NUCLEOTIDES

DNA(double helix) RNA(single)

Same phosphate group Same phosphate group

5-carbon sugar normally deoxyribose

5-carbon sugar normally ribose

Base pairs Guanine, Cytosine, Adenine and Thymine

Base pairs, Guanine, Adenine, Cytosine and Uracil.

JOINING NUCLEOTIDES

A condensation reaction between the phosphate group of one nucleotide and the sugar of another join the two together.

This forms chains called the “Backbone.” Organic bases will project from this, and it is this sequence of bases that forms coded information of nucleic acid.

HOW NUCLEOTIDES JOIN TOGETHER

DNA STRUCTURE

BASE PAIR- ACRONYM

Gangsters – Can

Ask - Time

A-T 2 H bonds

G-C 3 H-bonds

DRAW AND LABEL THE DIAGRAM EVERY COMPONENT AND BOND

DRAW AND LABEL

ribosomal RNA (rRNA)

Makes up the bulk of the ribosome.

Large folded molecule.

messenger RNA (mRNA)

Carries the genetic message from DNA in the nucleus to the ribosomes where proteins are synthesised (made) accordingly.

Long molecule, not folded.

Variable in length and base sequence.

Readily broken down and remade.

Collects amino acids and takes them to the ribosomes for assembly into proteins.

Small molecule.

Winds back on itself to form a “clover-leaf” shape.

One end carries an amino acid.

One loop has a special triplet of bases (ANTICODON) whichdetermines the amino acid carried.

transfer RNA (tRNA)

AMINO ACID

ANTICODON

RIBONUCLEIC ACID (RNA)

Single stranded polynucleotide.

Sugar is always ribose.

Organic bases are always A, G, C, and U, NEVER T.

3 types :- ribosomal RNA (rRNA)messenger RNA (mRNA)transfer RNA (tRNA)

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