Genetics, Stem Cell Research and Cloning

What Genetics, Stem Cell Research and Cloning covers

Genetics, Stem Cell Research and Cloning is examined in Unit A2 5, Genetics, Stem Cell Research and Cloning — examined, one of three optional units (Single Award takes one, Double Award two). It covers DNA structure and the evidence for the double helix, RNA, genes and the triplet code, genotype, phenotype and monohybrid inheritance, dihybrid crosses, epistasis and the chi-squared test, DNA replication and the Meselson–Stahl experiment, meiosis and genetic variation, insulin, factor VIII and chymosin from genetically modified microbes, recombinant DNA technology and gene cloning, genetic engineering, food supply and ethics, gene therapy and cystic fibrosis, genetic disease, screening and counselling, genetic fingerprinting and gel electrophoresis and stem cells, therapeutic cloning and their ethics.

The 13 subtopics

Each one has its own page.

• DNA structure and the evidence for the double helixNucleotides and the sugar–phosphate backbone, base pairing and hydrogen bonds, the stability of the double helix, Chargaff's rule with worked percentages, and the work of Franklin, Wilkins, Watson and Crick.Open →
• RNA, genes and the triplet codeRNA against DNA, messenger, transfer and ribosomal RNA, genes, loci and polypeptides, the triplet code with a worked base count, mutations and new alleles, substitutions and frameshift deletions.Open →
• Genotype, phenotype and monohybrid inheritanceGenotype and phenotype, dominant, recessive and codominant alleles, carrier crosses and probabilities, test crosses, sickle cell trait, sex linkage and haemophilia, and ABO multiple alleles.Open →
• Dihybrid crosses, epistasis and the chi-squared testDihybrid crosses and gametes, the 9:3:3:1 and test cross ratios, autosomal linkage and recombinants, epistasis in Labradors, and chi-squared tests on genetic crosses with worked values.Open →
• DNA replication and the Meselson–Stahl experimentConservative, semi-conservative and dispersive theories, the roles of helicase and DNA polymerase, and how Meselson and Stahl's 1958 nitrogen isotope experiment supported semi-conservative replication.Open →
• Meiosis and genetic variationHaploid gametes, homologous chromosomes, the two divisions of meiosis, independent segregation with worked combinations, crossing over and recombination, meiosis against mitosis and non-disjunction.Open →
• Insulin, factor VIII and chymosin from genetically modified microbesInsulin and diabetes, animal insulin and its problems, making human insulin with reverse transcriptase, Humulin and yeast, factor VIII and haemophilia, and rennet and chymosin in cheese making.Open →
• Recombinant DNA technology and gene cloningGene cloning and recombinant DNA, restriction enzymes and sticky ends, DNA ligase, vectors and plasmid uptake, marker genes, transgenic organisms, and medical and industrial uses of cloning.Open →
• Genetic engineering, food supply and ethicsSelective breeding against genetic engineering, crop yields and Golden Rice, transgenic animals producing human proteins such as albumin, and the ethical, environmental, economic and humanitarian arguments.Open →
• Gene therapy and cystic fibrosisGene therapy and its three approaches, somatic and germ cell therapy and UK law, the CFTR protein and cystic fibrosis symptoms, and early gene therapy trials with liposome and virus vectors.Open →
• Genetic disease, screening and counsellingSickle cell anaemia and malaria, aneuploidy, DNA sequencing, probes and PCR in screening, genetic counselling, oncogenes and tumour testing, carrier risk calculations and evaluating genetic testing.Open →
• Genetic fingerprinting and gel electrophoresisWhy DNA identifies individuals, Jeffreys' genetic fingerprinting, the stages of PCR, primers, gel electrophoresis and DNA ladders, paternity, forensics, breeding and marker probabilities.Open →
• Stem cells, therapeutic cloning and their ethicsTotipotent, pluripotent and adult stem cells, bone marrow transplants for leukaemia, Dolly the sheep, therapeutic and reproductive cloning, induced pluripotent stem cells, and the ethics and regulation of embryo research.Open →

What you need to know

Answer each one before you reveal it.

Take Genetics, Stem Cell Research and Cloning further

The same content, four other ways.

Commonly confused

Pairs that lose marks when they are blurred together.

• Genotype vs Phenotype

  Genotype: the set of alleles an organism carries. Phenotype: the observable features resulting from alleles and environment.

• Homozygous vs Heterozygous

  Homozygous: carrying two identical alleles at one locus. Heterozygous: carrying two different alleles at one locus.

• Totipotent vs Pluripotent

  Totipotent: able to form every cell type including the placenta. Pluripotent: able to form almost every body cell type but not the placenta.

Questions from this topic

Each one with the model answer underneath.

1. 1

   Why is DNA described as an information-carrying molecule?

   Model answer

   DNA stores information as the order of its bases along each strand. The base sequence determines the structure of the proteins a cell makes, including its enzymes.

2. 2

   Name the three components of a DNA nucleotide.

   Model answer

   A DNA nucleotide contains the sugar deoxyribose, a phosphate group and a nitrogen-containing base. The base is adenine, cytosine, guanine or thymine.

3. 3

   How are nucleotides joined to form a single strand of DNA?

   Model answer

   The phosphate of one nucleotide bonds to the deoxyribose of the next in a condensation reaction. The repeated sugar and phosphate groups form a sugar-phosphate backbone with the bases sticking out.

4. 4

   Which bases pair together in DNA, and how many hydrogen bonds link each pair?

   Model answer

   Adenine pairs with thymine through two hydrogen bonds. Cytosine pairs with guanine through three hydrogen bonds.

5. 5

   Describe how the two strands of a DNA molecule are arranged.

   Model answer

   Two sugar-phosphate backbones run in opposite directions, so the strands are antiparallel. Hydrogen bonds between paired bases hold the strands together, and the pair twists into a double helix.

6. 6

   Why is the width of the DNA double helix the same all along its length?

   Model answer

   A large two-ring base, adenine or guanine, always pairs with a small one-ring base, thymine or cytosine. Every rung of the ladder is therefore the same length.

What is inside Levo

Six ways to work the same material.

Genetics, Stem Cell Research and Cloning revision questions

What does Genetics, Stem Cell Research and Cloning cover in CCEA A-Level Life and Health Sciences?

13 subtopics: dna structure and the evidence for the double helix, rna, genes and the triplet code, genotype, phenotype and monohybrid inheritance, dihybrid crosses, epistasis and the chi-squared test, dna replication and the meselson–stahl experiment, meiosis and genetic variation, insulin, factor viii and chymosin from genetically modified microbes, recombinant dna technology and gene cloning, genetic engineering, food supply and ethics, gene therapy and cystic fibrosis, genetic disease, screening and counselling, genetic fingerprinting and gel electrophoresis and stem cells, therapeutic cloning and their ethics. Each one has its own page with questions and model answers.

How is Genetics, Stem Cell Research and Cloning organised?

By the CCEA 0008 specification, subtopic by subtopic, so it matches the order you are taught it in.