This fully-resourced lesson describes how post-transcriptional changes to mRNA enable 1 gene to give rise to multiple proteins. The detailed PowerPoint and accompanying resources have been designed to cover point 3.19 of the Edexcel International A-level Biology specification.
The lesson begins with a knowledge recall as the students have to recognise the definition of a gene as a sequence of bases on a DNA molecule that codes for a sequence of amino acids in a polypeptide chain. This description was introduced in topic 2 and the aim of the start of the lesson is to introduce the fact that despite this definition, most of the nuclear DNA in eukaryotes doesn’t actually code for proteins. A quick quiz competition is then used to introduce exons as the coding regions within a gene before students are challenged to predict the name of the non-coding regions and then to suggest a function for these introns. Moving forwards, pre-mRNA as a primary transcript is introduced and students will learn that this isn’t the mature strand that moves off to the ribosome for translation. Instead, a process called splicing takes place where the introns are removed and the remaining exons are joined together. Another quick quiz round leads to an answer of 20000 and students will learn that this is the number of protein-coding genes in the human genome. Importantly, the students are then told that the number of proteins that are synthesised is much higher than this value and a class discussion period encourages them to come up with biological suggestions for this discrepancy between the two numbers. The lesson concludes with a series of understanding and application questions where students will learn that alternative splicing enables a gene to produce more than a single protein and that this natural phenomenon greatly increases biodiversity.
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DNA, RNA, Genetics and Inheritance (Edexcel Int. A-level Biology)
This lesson bundle contains 16 lessons which have been designed to cover the Edexcel International A-level Biology specification points which focus on the structure of DNA and RNA, their roles in replication and protein synthesis, and genetics and inheritance. The lesson PowerPoints are highly detailed, and along with their accompanying worksheets, they have been planned at length to contain a wide range of engaging tasks which cover the following A-level Biology content found in topics 2, 3 and 6 of the course: 2.9 (i): Know the basic structure of mononucleotides (deoxyribose or ribose linked to a phosphate and a base, including thymine, uracil, adenine, cytosine or guanine) and the structures of DNA and RNA (polynucleotides composed of mononucleotides linked by condensation reactions to form phosphodiester bonds) 2.9 (ii): Know how complementary base pairing and the hydrogen bonding between two complementary strands are involved in the formation of the DNA double helix 2.10 (i): Understand the process of DNA replication, including the role of DNA polymerase 2.11: Understand the nature of the genetic code 2.12: Know that a gene is a sequence of bases on a DNA molecule that codes for a sequence of amino acids in a polypeptide chain 2.13 (i): understand the process of protein synthesis (transcription and translation), including the role of RNA polymerase, translation, messenger RNA, transfer RNA, ribosomes and the role of start and stop codons 2.13 (ii): Understand the roles of the DNA template (antisense) strand in transcription, codons on messenger RNA and anticodons on transfer RNA 2.14 (i): Understand how errors in DNA replication can give rise to mutations (substitution, insertion and deletion of bases) 2.14 (ii): Know that some mutations will give rise to cancer or genetic disorders, but that many mutations will have no observable effect 2.15 (i): Know the meaning of the terms: gene, allele, genotype, phenotype, recessive, dominant, codominance, homozygote and heterozygote 2.15 (ii): Understand patterns of inheritance, including the interpretation of genetic pedigree diagrams, in the context of monohybrid inheritance 2.15 (iii): Understand sex linkage on the X chromosome, including red-green colour blindness in humans 2.16: Understand how the expression of a gene mutation in people with cystic fibrosis impairs the functioning of the gaseous exchange, digestive and reproductive systems 2.17 (i): Understand the uses of genetic screening, including the identification of carriers, pre-implantation genetic diagnosis (PGD) and prenatal testing, including amniocentesis and chorionic villus sampling 2.17 (ii): Understand the implications of prenatal genetic screening 3.9 (i): Know that a locus is the location of genes on a chromosome 3.9 (ii): Understand the linkage of genes on a chromosome 3.18: Understand how cells become specialised through differential gene expression, producing active mRNA, leading to the synthesis of proteins which, in turn, control cell processes or determine cell structure in animals and plants 3.19: Understand how one gene can give rise to more than one protein through posttranscriptional changes to messenger RNA (mRNA). 3.20 (i): Phenotype is an interaction between genotype and the environment 3.21: Understand how some phenotypes are affected by multiple alleles for the same gene at many loci (polygenic inheritance) as well as the environment and how this can give rise to phenotypes that show continuous variation 6.17: Know how DNA can be amplified using the polymerase chain reaction (PCR)
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Topic 3: Cell structure, Reproduction & Development (Edexcel International A-level Biology)
The locus and linkage, meiosis, differential gene expression and protein transport within cells lessons have been uploaded for free and by downloading these, you will be able to observe the detail of planning that has gone into all of the lessons that are included in this bundle. This intricate planning ensures that the students are engaged and motivated whilst the detailed content of topic 3 (Cell structure, Reproduction and Development) of the Edexcel International A-level Biology specification is covered. The 12 lesson PowerPoints and accompanying resources contain a wide range of activities which cover the following topic 3 specification points: * All living organisms are made of cells * Cells of multicellular organisms are organised into tissues, organs and organ systems * The ultrastructure of eukaryotic cells * The function of the organelles in eukaryotic animal cells * The role of the RER and Golgi apparatus in protein transport within cells * The ultrastructure of prokaryotic cells * Magnification and resolution in light and electron microscopes * The gene locus is the location of a gene on a chromosome * The linkage of genes on a chromosome * The role of meiosis in ensuring genetic variation * Understand how the mammalian gametes are specialised for their functions * The role of mitosis and the cell cycle in growth and asexual reproduction * The meaning of the terms stem cell, pluripotent, totipotent, morula and blastocyst * The decisions that have to be made about the use of stem cells in medical therapies * Cells become specialised through differential gene expression * One gene can give rise to more than one protein through post-transcriptional changes to mRNA * Phenotype is the interaction between genotype and the environment * Some phenotypes are affected by multiple alleles or by polygenic inheritance Due to the detail included in all of these lessons, it is estimated that it will take in excess of 6 weeks of allocated A-level teaching time to complete the teaching of the bundle
£16.00
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