NUCLEIC ACIDS: THE RNA

Nucleic Acids:RNA

By:Lily Rosemary L.

Masilang

Overview:

Structure of Nucleic Acids Five Common BasesRNA: DefinitionComposition of Ribonucleic acidComponents of Nucleic AcidsStructure of Ribonucleic acidTypes of RNAFunctions of RNAProtein Synthesis

The Structure of Nucleic Acids

The Structure of Nucleic Acids

The Structure of Nucleic Acids

Five Common BasesAbbr. Base Nucleoside Nucleic

Acid

A Adeninedeoxyadenos

ine DNA

adenosine RNA

G Guaninedeoxyguanos

ine DNA

guanosine RNA

C Cytosinedeoxycytidin

e DNA

cytidine RNA

T Thyminedeoxythymid

ine (thymidine)

DNA

U Uracil uridine RNA

RNA: DefinitionShort for Ribonucleic acid  

A substance in the cells of plants and animals that helps make proteins.

is a polymeric molecule implicated in various biological roles in coding, decoding, regulation, and expression of genes.

Composition of RNA

Components of Nucleic Acids

Food with rich and low purines

• Similar to DNA but with some important differences:– Single strand – The sugar is Ribose– Uracil matches Adenine– Shorter than DNA

Structure of RNA

• RNA does not form an analogous double helical structure.

• RNA form a heteromeric double helix.

Structure of RNA

Structure of RNA

• Many RNA molecules have secondary structure in which intermolecular loops formed by complementary pairing.

Types of RNA• Messenger RNA (mRNA)• Ribosmal RNA (rRNA)• Transfer RNA (tRNA)

Other types of RNAo Small nuclear RNA (SnRNA),o Micro RNA(miRNA) ando Small interfering RNA(SiRNA) ando Small Nucleolar RNAs (snoRNA)o Riboswitches

Messenger RNA• Used as template to make

proteins• Carries instructions for

polypeptide synthesis from nucleus to ribosomes in the cytoplasm.

• The 5’ terminal end is capped by 7- methyl guanosine triphosphate cap.

Ribosomal RNA• Makes up the ribosomes.• Forms an important part of both

subunits of the ribosomes.• Component performs the

peptidyl transferase activity and thus is an enzyme (a ribozyme).

Transfer RNAThey transfer the amino acids from

cytoplasm to the protein synthesizing machinery, hence the name tRNA.

Matches amino acids to mRNA to help make proteins.

Key to the translation process of mRNA sequence into the amino acids sequence of proteins.

Structure of tRNA

• Primary structure- The nucleotide sequence of all the tRNA molecules allows extensive intrastand complimentarity that generates a secondary structure.

• Secondary structure- Each single tRNA shows extensive internal base pairing and acquires a clover leaf like structure. The structure is stabilized by hydrogen bonding between the bases and is a consistent feature.

Tertiary structure-The L shaped tertiary structure is formed by further folding of the clover leaf due to hydrogen bonds between T and D arms.

The base paired double helical stems get arranged in to two double helical columns, continuous and perpendicular to one another.

Structure of tRNA

Other types of RNA• Small Nuclear RNAs- play a critical role in gene

regulation by way of RNA splicing.– The splicing of pre-mRNA give rise to mature

mRNA.• MicroRNAs- have been shown to inhibit gene

expression by repressing translation– also play significant roles in cancer and other

diseases• Small Interfering RNAs-  they also work to inhibit

gene expression– They may have evolved as a defense mechanism

against double-stranded RNA viruses.

• Small Nucleolar RNAs- These molecules function to process rRNA molecules, often resulting in the methylation and pseudouridylation of specific nucleosides

• Riboswitches- are RNA sensors that detect and respond to environmental or metabolic cues and affect gene expression accordingly

Other types of RNA

Functions of RNA

• Its principal role is to act as a messenger carrying instructions from DNA for controlling the synthesis of proteins,

• In some viruses RNA rather than DNA carries the genetic information.

Protein synthesis

the process by which individual amino acids are connected to each other in a specific order dictated by the nucleotide sequence in DNA.

 process by which the genetic code puts

together proteins in the cell.

Protein Synthesis

• The production of proteins by an individual cell.

• The genetic information stored in DNA is used as a blueprint for making proteins.

• Why Proteins?

The Process of Protein Synthesis

TranscriptionInitiation

RNA polymerase

Elongation Transcription

Termination Transcription

References• http

://www.vivo.colostate.edu/hbooks/genetics/biotech/basics/nastruct.html

• http://www.whatislife.com/reader/dna-rna/dna-rna.html 

• https://www2.chemistry.msu.edu/faculty/reusch/virttxtjml/nucacids.htm

• http://www.nature.com/scitable/definition/ribonucleic-acid-rna-45

• http://www.nature.com/scitable/definition/ribonucleic-acid-rna-45

• http://www.slideshare.net/namarta28/rna• http://chemistry.tutorvista.com/biochemist

ry/nucleic-acid-function.html• http://slideplayer.com/slide/4640877/• http://www.nature.com/scitable/topicpage/

rna-functions-352• http://chemistry.elmhurst.edu/vchembook/

584proteinsyn.html• www.phschool.com/science/biology_place/

biocoach/translation/init.html

References

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