Biology · Edexcel Paper 1
DNA and Protein Synthesis
The structure of DNA, the genome and the Human Genome Project, how to extract DNA from fruit, and then, for Higher tier separate Biology, how a gene's code is turned into a protein and how variants change it. Matches Edexcel 3.4 to 3.10B and 3.21. The first three lessons are for both Combined Science and separate Biology at Foundation and Higher. The last three lessons are Higher tier and separate Biology only.
Lessons
Ticks are remembered on this device only.
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1
The Structure of DNA
DNA carries the instructions for building every living thing. This lesson looks at its structure: a polymer of nucleotides, with two strands joined by…
10 terms -
2
The Genome and the Human Genome Project
A genome is an organism's complete set of DNA. This lesson explains what the human genome contains, how the Human Genome Project mapped it, and how knowing the…
9 terms -
3
Extracting DNA from Fruit
You can see DNA with your own eyes. This lesson explains a simple method to extract DNA from fruit using household chemicals, why each step is needed, and how…
9 terms -
4
From Genes to Proteins (Higher tier)
A gene is a code for a protein. This lesson is for separate Biology only, and for the Higher tier only: Combined Science and Foundation students do not need…
9 terms -
5
Protein Synthesis (Higher tier)
A protein is made in two stages: transcription in the nucleus and translation at a ribosome. This lesson is for separate Biology only, and for the Higher tier…
10 terms -
6
Genetic Variants and Their Effects (Higher tier)
A change in the DNA can change a protein. This lesson is for separate Biology only, and for the Higher tier only: Combined Science and Foundation students do…
10 terms
Key terms in this chapter
All 57, gathered from every lesson.
- DNA
- Deoxyribonucleic acid: the molecule that carries the genetic code, made of two strands in a double helix.
- Polymer
- A long molecule made of many small repeating units joined together.
- Nucleotide
- The repeating unit of DNA, made of a sugar, a phosphate group and a base.
- Base
- One of the four chemicals (A, T, C or G) in a nucleotide, whose order forms the genetic code.
- Complementary base pairing
- The rule that A pairs with T and C pairs with G.
- Double helix
- The shape of DNA: two strands twisted around each other.
- Hydrogen bond
- A weak bond that holds the paired bases of the two DNA strands together.
- Sugar-phosphate backbone
- The outer part of each DNA strand, made of alternating sugar and phosphate groups.
- Adenine
- The base A, which pairs with thymine.
- Guanine
- The base G, which pairs with cytosine.
- Genome
- The entire DNA of an organism.
- Gene
- A section of a DNA molecule that codes for a specific protein.
- Human Genome Project
- An international project, completed in 2003, that found the order of all of the bases in human DNA.
- Sequencing
- Finding the order of bases in a piece of DNA.
- Non-coding DNA
- DNA that does not code for a protein, but may help to control genes.
- Genetic test
- A test that looks for a particular variant of a gene in a person's DNA.
- Personalised medicine
- Choosing a treatment that suits a person according to their own genes.
- Gene therapy
- Treating a genetic disorder by changing or replacing the faulty gene.
- Inherited disorder
- A condition caused by a faulty gene that is passed from parents to children.
- Extraction
- Separating a substance from the material it is in.
- Detergent
- A chemical that breaks down cell membranes by dissolving the lipids in them.
- Filtering
- Separating solid pieces from a liquid, using filter paper.
- Filtrate
- The liquid that passes through a filter.
- Ethanol
- A type of alcohol in which DNA is insoluble, which makes DNA come out of solution.
- Precipitate
- A solid that forms from a solution.
- Insoluble
- Does not dissolve in a particular liquid.
- Cell membrane
- The outer layer of an animal or plant cell, made of lipids and proteins.
- Mashing
- Crushing something into a soft mass.
- Protein
- A molecule made of one or more chains of amino acids, folded into a specific shape.
- Amino acid
- The small unit that proteins are made from. There are 20 different ones.
- Polypeptide
- A long chain of amino acids.
- Triplet
- A group of three bases in DNA that codes for one amino acid.
- Genetic code
- The set of rules that links triplets of bases to the amino acids they code for.
- Active site
- The part of an enzyme where the substrate binds, with a shape that fits the substrate.
- Specific shape
- A precise three-dimensional structure that allows a protein to carry out its function.
- Antibody
- A protein made by the immune system that binds to one particular antigen.
- Receptor
- A protein that binds to a specific chemical, such as a hormone.
- Transcription
- Making a complementary mRNA copy of a gene from DNA.
- Translation
- Reading the code in mRNA at a ribosome to build a polypeptide.
- RNA polymerase
- The enzyme that makes mRNA by joining RNA nucleotides complementary to the DNA.
- mRNA
- Messenger RNA: a single-stranded copy of a gene that carries the code to a ribosome.
- tRNA
- Transfer RNA: a molecule that carries a particular amino acid to the ribosome.
- Codon
- A group of three bases in mRNA that codes for one amino acid.
- Anticodon
- The three bases on a tRNA molecule that pair with a codon.
- Ribosome
- The structure in the cytoplasm that reads mRNA and builds the polypeptide.
- Uracil
- The base in RNA that takes the place of thymine, and pairs with adenine.
- Non-coding DNA
- DNA that does not code for a protein, including the region in front of a gene where RNA polymerase binds.
- Genetic variant
- A difference in the base sequence of DNA between individuals.
- Mutation
- A change in the base sequence of DNA.
- Substitution
- A mutation in which one base is replaced by another.
- Insertion
- A mutation in which one or more bases are added.
- Deletion
- A mutation in which one or more bases are removed.
- Frameshift
- An insertion or deletion that changes how all of the following triplets are read.
- Coding DNA
- The part of a gene that codes for the sequence of amino acids in a protein.
- Non-coding DNA
- DNA that does not code for a protein, such as the region in front of a gene where RNA polymerase binds.
- Phenotype
- The observable characteristics of an organism, produced by its genes and the environment.
- Sickle cell disease
- An inherited disease caused by a variant in the haemoglobin gene, which distorts red blood cells.