Table of Contents
- The genetic code in cells is made up of DNA.
- DNA specifies the construction of proteins and the generation of RNA.
- DNA and RNA are nucleotide polymers.
Structure of nucleic acids
- Nucleic acids are information molecules in cells.
- Deoxyribonucleic acid is the most famous nucleic acid.
- Ribonucleic acid is less known and very important in cells.
- Nucleic acid polymers are made up of repeating nucleotide monomers.
- The structure of nucleic acid is complex because of the following reasons:
- The nucleic acid monomers are nucleotides. Nucleotides contain 3 components which makes them complicated before the formation of chains.
- Nucleic acids can be double-stranded or single-stranded. Joining nucleotides together leads to the formation of polynucleotide chains.
- RNA has a single polynucleotide chain while DNA has two double -helix polynucleotide chains.
- Nucleotides are built from 3 components;
- Pentose sugar (5 carbon) – DNA has deoxyribose sugar while RNA has a ribose sugar
- Nitrogenous base – It is a double ring structure or a single ring structure containing many nitrogen atoms
- Phosphate group – Contains a phosphorus atom that is surrounded by atoms of oxygen. They have a negative charge which makes nucleic acids negative in charge.
- Carbon atoms on nucleotides are numbered using the following system:
- The sugar carbon atoms are numbered in a sequence from one to five.
- The numbered carbon atoms are awarded a prime designation resulting in 1′, 2′, 3′,4′ and 5′.
- Oneprime carbon is the first carbon.
- All other carbon atoms are numbered consecutively.
The naming of nucleotide bases
- There are five nitrogenous bases found on nucleotides. This includes the following:
- Adenine (A)
- Guanine (G)
- Cytosine (C)
- Thymine (T)
- Nucleotides vary depending on the nitrogenous base attached to it.
- Nitrogenous bases fall into two categories:
- Pyrimidine- Contain a single ring structure and two nitrogen atoms.
- Purines- contain 2 fused rings with each ring containing two nitrogen atoms.
DNA and RNA synthesis
- Nucleotides are joined together by a condensation reaction.
- Repeating the process leads to the formation of a polynucleotide.
- A primary structure is formed by the type and number of nucleotides.
Differences between RNA and DNA
- DNA has thymine nitrogenous base while RNA has uracil base.
- DNA nucleotides have a deoxyribose sugar while RNA nucleotides have a ribose sugar.
- RNA is single-stranded while DNA is double-stranded.
The DNA double helix
- The DNA secondary structure is a double helix.
- Two chains of polynucleotides join to form a molecule with a twisted ladder-like shape.
- The sides of the ladder represent the Sugar phosphate backbones.
- Nitrogenous bases project from the sugar backbone.
- The two double helix chains are antiparallel.
- The antiparallel strands are joined by hydrogen bonds between bases.
- Adenine (A) joins to Thymine (T) by hydrogen bonds.
- Cytosine (C) joins Guanine (G) by hydrogen bonds.
The function of DNA and RNA
- Protein structure; the structure of proteins is determined by the DNA nucleotide sequence. Protein is generated from the process of transcription and translation.
- RNA structure; the structure of RNA id determined by the DNA nucleotide sequence. The process of transcription generates nucleotides required to build RNA.
- DNA regulation; it happens through the interaction of DNA binding proteins with special DNA regulatory sequences.
Types of RNA and their function
- Messenger RNA (mRNA) carries a protein structure code from DNA to ribosomes where proteins are generated.
- Transfer RNA (tRNA) decodes the mRNA message by allocating an amino acid that matches to the mRNA code.
- Ribosomal RNA (rRNA) is part of the structure of the ribosome.
|Structure of RNA
|Single strand of nucleotides, ribose sugar, uracil (instead of thymine)
|Adenine pairs with…
|Uracil pairs with…
|Guanine pairs with…
|Cytosine pairs with…
|Function of mRNA
|Carries genetic information from DNA in the nucleus to the cytosol in eukaryotic cells
|Structure of mRNA
|Single uncoiled chain
|Function of tRNA
|Amino acids bind to it and it carries the amino acid to the ribosome for protein synthesis
|Shape of tRNA
|Single chain (about 80 nucleotides) in hairpin shape
|Number of tRNA varieties
|Most abundant form of RNA
|Function of rRNA
|Site of protein synthesis
|Structure of rRNA
|Globular shape composed of rRNA and proteins
|Transfer of genetic information from DNA to RNA
|Location of transcription
|In the nucleus
|At the beginning of the gene
|Enzyme used in transcription
|Role of RNA Polymerase in transcription
|Binds to promoter region and causes DNA to separate
|Nucleotide sequence at the beginning of a gene, shows RNA Polymerase where to bind
|Series of Thymine and Adenine on the DNA template
|Template strands used in transcription
|One strand of DNA
|Specific sequence of nucleotides on the DNA template that signals the end of transcription
|When RNA Polymerase hits the termination signal
|RNA Polymerase action at termination signal
|Breaks off from the DNA template and the mRNA
|Reusability of DNA template
|Yes, it can be reused to make more mRNA
|Product of transcription
|mRNA (called transcript)
|Destination of mRNA after transcription
|Out of the nucleus (through nuclear pores) and into the cytosol where it binds to a ribosome
|Every 3 mRNA nucleotides
|Codes for a particular amino acid
|Determinant of amino acid sequence in the protein
|Number of codons
|Codon that signals the ribosome to start translation of mRNA
|AUG codes for
|UAA, UAG, and UGA
|Process of assembling polypeptides from the coded message of mRNA
|Requirements for translation
|Ribosome and tRNA
|Ribosome’s role in translation
|Holds mRNA in place
|tRNA’s role in translation
|Transports amino acids to mRNA
|Composition of a ribosome
|rRNA and proteins
|Number of binding sites on a ribosome
|Function of the first binding site
|Holds mRNA transcript in place
|Function of the second and third binding sites
|Allow tRNA to bind to them
|A region where the amino acid binds and the opposite side contains an anticodon
|The complement of a codon triplet on mRNA
|Start of polypeptide assembly
|Ribosome attaches to the start codon (AUG)
Get help to do your homework
We have top writers to get your essays done professionally. Place your order today to receive an original paper via email.Write my Paper
|What are nucleic acids made up of?
|What is the function of nucleic acids?
|Carry genetic information and instructions for cell functioning
|What are the two main types of nucleic acids?
|DNA and RNA
|Where is DNA found in eukaryotes?
|Nucleus, chloroplasts, and mitochondria
|Is DNA enclosed in a nucleus in prokaryotes?
|What is the entire genetic content of a cell called?
|What forms eukaryotic chromosomes?
|DNA and histone proteins (chromatin)
|What is the function of DNA?
|Control cellular activities by turning genes “on” or “off”
|What is the function of RNA?
|Involved in protein synthesis and regulation
|What are the nitrogenous bases in DNA?
|Adenine (A), guanine (G), cytosine (C), and thymine (T)
|What are the nitrogenous bases in RNA?
|Adenine (A), guanine (G), cytosine (C), and uracil (U)
|What is the sugar in RNA?
|What is the sugar in DNA?
|What are the three components of a nucleotide?
|Nitrogenous base, pentose sugar, and phosphate group
|What type of bonds link nucleotides in a nucleic acid?
|What type of bonding holds the two strands of DNA together?
|What is the rule for base pairing in DNA?
|A can only pair with T, and G can only pair with C
|How is DNA able to replicate?
|Complementary strands allow for each strand to serve as a template for the synthesis of a new strand
|How is DNA compacted in prokaryotes?
|How is DNA compacted in eukaryotes?
|Wrapping around histones to form nucleosomes and further compaction into 30 nm fibers
|What are the two regions of eukaryotic chromosomes in interphase?
|Heterochromatin and euchromatin
|What are the four major types of RNA?
|mRNA, rRNA, tRNA, and miRNA
|What is the function of mRNA?
|Carries genetic code from DNA and serves as a template for protein synthesis
|What is the function of rRNA?
|Major component of ribosomes for protein synthesis
|What is the function of tRNA?
|Carries correct amino acids to the site of protein synthesis
|What is the function of miRNA?
|Regulates gene expression
|What is the Central Dogma of Molecular Biology?
|DNA transcribed into mRNA, which is then translated into protein
Cite this article in APA
If you want to cite this source, you can copy and paste the citation below.
Editorial Team. (2023, May 29). DNA and RNA: Instructions for Life. Help Write An Essay. Retrieved from https://www.helpwriteanessay.com/blog/dna-and-rna-instructions-for-life/