Biology AS Edexcel Snab Revision
-
lifestyle-health-and-risk as19 主题
-
diet-and-health interpreting-data-on-risk-factors
-
diet-and-health treatment-of-cvd
-
diet-and-health energy-budgets-and-diet
-
diet-and-health monosaccharides
-
diet-and-health the-glycosidic-bond
-
diet-and-health disaccharides
-
diet-and-health polysaccharides
-
diet-and-health lipids-and-ester-bonds
-
diet-and-health reducing-risk-factors-of-cvd
-
diet-and-health practical-vitamin-c-content
-
the-circulatory-system the-need-for-a-circulatory-system
-
the-circulatory-system the-importance-of-water-in-transport
-
the-circulatory-system mammalian-heart-structure-and-function
-
the-circulatory-system blood-vessels-structure-and-function
-
the-circulatory-system cardiac-cycle
-
the-circulatory-system investigating-heart-rate
-
the-circulatory-system atherosclerosis
-
the-circulatory-system blood-clotting
-
diet-and-health cardiovascular-disease
-
diet-and-health interpreting-data-on-risk-factors
-
genes-and-health as28 主题
-
gas-exchange-cell-membranes-and-transport properties-of-gas-exchange-surfaces
-
gas-exchange-cell-membranes-and-transport ficks-law-of-diffusion
-
gas-exchange-cell-membranes-and-transport the-mammalian-lung
-
gas-exchange-cell-membranes-and-transport cell-membranes
-
gas-exchange-cell-membranes-and-transport practical-investigating-membrane-permeability
-
gas-exchange-cell-membranes-and-transport diffusion-and-facilitated-diffusion
-
gas-exchange-cell-membranes-and-transport active-transport
-
gas-exchange-cell-membranes-and-transport osmosis
-
nucleic-acids nucleotides-and-phosphodiester-bonds
-
nucleic-acids dna-structure
-
nucleic-acids rna-structure
-
proteins transcription
-
proteins translation
-
proteins nature-of-the-genetic-code
-
proteins amino-acids-and-peptide-bonds
-
proteins levels-of-protein-structure
-
proteins globular-proteins-structure-and-function
-
proteins fibrous-proteins-structure-and-function
-
proteins the-role-of-enzymes
-
proteins mode-of-enzyme-action
-
proteins enzyme-and-substrate-concentrations
-
inheritance dna-replication
-
inheritance mutations
-
inheritance inheritance-key-terms
-
inheritance pedigree-diagrams
-
inheritance monohybrid-crosses
-
inheritance chi-squared-test
-
inheritance genetic-screening
-
gas-exchange-cell-membranes-and-transport properties-of-gas-exchange-surfaces
-
voice-of-the-genome as19 主题
-
cell-structure-and-organisation cell-theory
-
cell-structure-and-organisation eukaryotic-cells
-
cell-structure-and-organisation prokaryotic-cells
-
cell-structure-and-organisation organisation-of-cells
-
cell-structure-and-organisation microscopy
-
cell-structure-and-organisation magnification-calculations
-
cell-structure-and-organisation recognising-organelles
-
cell-division the-cell-cycle
-
cell-division mitosis
-
cell-division practical-identifying-mitosis-in-plant-cells
-
reproduction-and-inheritance mammalian-gametes
-
reproduction-and-inheritance fertilisation-in-mammals
-
reproduction-and-inheritance genes-and-linkage
-
reproduction-and-inheritance meiosis-source-of-genetic-variation
-
differentiation-and-variation stem-cells
-
differentiation-and-variation stem-cells-in-medicine
-
differentiation-and-variation cell-differentiation
-
differentiation-and-variation epigenetics
-
differentiation-and-variation phenotypes-and-variation
-
cell-structure-and-organisation cell-theory
-
biodiversity-and-natural-resources as19 主题
-
biodiversity the-variety-of-life
-
biodiversity measuring-biodiversity-within-a-habitat
-
biodiversity comparing-biodiversity-between-habitats
-
biodiversity ecological-niches-and-adaptations
-
biodiversity natural-selection
-
biodiversity hardy-weinberg-equation
-
biodiversity reproductive-isolation
-
biodiversity classification
-
biodiversity conservation-of-biodiversity
-
resources-from-plants plant-cell-structure
-
resources-from-plants plant-stems
-
resources-from-plants importance-of-water-and-inorganic-ions-to-plants
-
resources-from-plants starch-and-cellulose-structure-and-function
-
resources-from-plants plant-fibres
-
resources-from-plants practical-identifying-tissue-types-within-stems
-
resources-from-plants tensile-strength-plant-fibres
-
resources-from-plants development-of-drug-testing
-
resources-from-plants antimicrobial-properties-of-plants
-
resources-from-plants sustainability-and-plant-materials
-
biodiversity the-variety-of-life
proteins translation
Exam code:8BN0
Translation
-
Translation occurs in the cytoplasm of the cell
-
After leaving the nucleus via a nuclear pore, the mRNA molecule attaches to a ribosome
-
In the cytoplasm there are free molecules of tRNA (transfer RNA)
-
tRNA is a single stranded molecule of RNA that folds into a clover-like structre
-
tRNA molecules have a triplet of unpaired bases at one end, known as the anticodon, and a region at the other end where a specific amino acid can attach
-
There are about 20 different tRNA molecules, each with a specific anticodon and specific amino acid binding site
-
-
The tRNA molecules bind with their specific amino acids (also in the cytoplasm) and bring them to the mRNA molecule on the ribosome
-
The triplet of bases (anticodon) on each tRNA molecule pairs with a complementary triplet on the mRNA molecule called the codon
-
Near the beginning of the mRNA is a triplet of bases called the start codon (AUG)
-
This is a signal to start off translation
-
AUG codes for an amino acid called methionine
-
-
Two tRNA molecules fit onto the ribosome at any one time, bringing the amino acid they are each carrying side by side
-
A peptide bond is then formed, via a condensation reaction, between the two amino acids
-
This process continues until a ‘stop’ codon on the mRNA molecule is reached – this acts as a signal for translation to stop and at this point the amino acid chain coded for by the mRNA molecule is complete
-
The amino acid chain then forms the final polypeptide
The process of translation
Examiner Tips and Tricks
Make sure you learn both stages of protein synthesis fully. Don’t forget – transcription occurs in the nucleus but translation occurs in the cytoplasm!
Responses