BRAINCAKEDNA, Genes and Protein Synthesis
Revision notes for DNA, Genes and Protein Synthesis in Edexcel Biology (8BI0). Read the start of any lesson here, then sign in free for the whole lesson, the R.E.C.I.P.E. recall steps and the quiz.
- NucleotidesNucleotides are the monomers that make up the nucleic acids DNA and RNA.
- ATPATP (adenosine triphosphate) is the immediate source of energy in all cells.
- Nucleic AcidsThe nucleic acids, DNA and RNA, are polymers of nucleotides, so they are called polynucleotides.
- Phosphodiester BondsNucleotides are joined into a polynucleotide chain by phosphodiester bonds.
- Complementary Base PairingThe two strands of a DNA double helix are held together by hydrogen bonds between the bases.
- Evidence for Semi-Conservative DNA ReplicationWhen Watson and Crick described DNA, three ways of copying it were possible: • conservative: the original molecule stays intact and a completely new…
- DNA ReplicationDNA is copied before a cell divides, during interphase, so that each daughter cell receives an identical copy.
- The Genetic CodeThe genetic code is the set of rules by which the base sequence of DNA (and mRNA) is converted into the amino acid sequence of a polypeptide.
- Types of RNARNA (ribonucleic acid) is a polynucleotide made of nucleotides containing ribose, a phosphate group and one of the bases A, U, C or G.
- mRNAMessenger RNA (mRNA) carries the genetic information of a gene from DNA, which stays in the nucleus, to the ribosomes in the cytoplasm where the…
- tRNATransfer RNA (tRNA) brings amino acids to the ribosome in the correct order during translation.
- rRNARibosomal RNA (rRNA) is the most abundant type of RNA in a cell.
- Protein SynthesisA gene is a sequence of bases on a DNA molecule that codes for the sequence of amino acids in a polypeptide.
- TranscriptionTranscription is the first stage of protein synthesis: a gene's base sequence is copied into mRNA.
- TranslationTranslation is the second stage of protein synthesis: the mRNA base sequence is used to make a polypeptide with a specific amino acid sequence.
- PolysomesA single mRNA molecule does not have to be translated by just one ribosome at a time.
- MutationsA mutation is a change in the genetic material of a cell.
- Gene MutationA gene mutation (point mutation) changes one or a few bases in the DNA of a gene.
- Sickle Cell DiseaseSickle cell disease is an inherited disorder caused by a single base substitution in the gene for the β-globin chain of haemoglobin.
- Chromosome MutationsChromosome mutations affect large sections of DNA or whole chromosomes, so they usually change many genes at once.