RNA meaning | - Ribonucleic acid |
DNA meaning | - Deoxyribonucleic acid |
What monomers make up DNA | - Nucleotides |
Nucleotide structure | - A pentose sugar (as it has 5 carbons)
- A phosphate group
- A nitrogen-containing organic base |
Mononucleotides | - One nucleotide |
Dinucleotides | - Two nucleotides
- Bonded together through the joining of the deoxyribose sugar of one and the phosphate group of the other |
Polynucleotides | - Long chain of nucleotides |
Phosphodiester bond | - Condensation reaction between a pentose sugar, a phosphate group and an organic base
- Bonding them together |
Types of nitrogen-containing organic bases | - Cytosine C
- Thymine T
- Uracil U
- Adenine A
- Guanine G |
Ribonucleic acid (RNA) structure | - Polymer
- Single, short polynucleotide chain
- Pentose sugar is always ribose
- Organic bases are cytosine, uracil, adenine, guanine |
Different functions of different types of RNA | - Transfers genetic information from DNA to the ribosomes
- Ribosomes are made up of proteins and another type of RNA
- Involved in protein synthesis |
DNA structure | - Polymer
- Made up of two strands of nucleotides forming a double helix
- Pentose sugar is always deoxyribose
- Organic bases are cytosine, thymine, adenine, guanine |
Strands of nucleotides (DNA structure) | - Each of the two strands is very long
- Joined together by hydrogen bonds formed between certain bases |
Base pairing | - Adenine always pairs with thymine
- Guanine always pairs with cytosine
- They are complementary to one another |
The double helix | - Two polynucleotide strands that are anti-parallel
- Strong phosphodiester bonds joining the backbone
- Hydrogen bonds joining nucleotides between base parings |
The stability of DNA | - The phosphodiester backbone protects the more chemically reactive organic bases
- Hydrogen bonds link organic base pairs
- There are 3 hydrogen bonds between cytosine and guanine, the higher the proportion of C-G pairings the more stable the DNA molecule |
Function of DNA | - Carries genetic code
- Has instructions to make proteins |
How DNA is adapted for its function | - Very stable structure, most mutations are repaired
- Strands joined by hydrogen bonds, allows them to separate during DNA replication + protein synthesis
- Large, carries more genetic information |
RNA (differences between DNA and RNA) | - Single stranded
- Smaller
- Uracil present
- Has a ribose sugar
- Leaves the nucleus |
DNA (differences between DNA and RNA) | - Double stranded
- Larger
- Thymine present
- Has a deoxyribose sugar
- Stays in the nucleus |
Explain how a change in the DNA base sequence for a protein may result in a change in the structure of the protein | - A change in the sequence of amino acids means bonds in different places
- This results in a different tertiary structure of proteins and that alters the function of the protein. |
What is a codon | - A sequence of three nucleotides which forms genetic code
- Anticodon complementary to codon |