5 interactive labs · AS & A Level Biology 9700
· Draw α- and β-glucose, join and split disaccharides, then build amylose, glycogen and cellulose and hydrolyse them from their ends.
Draw α- and β-glucose, join and split disaccharides, then build amylose, glycogen and cellulose and hydrolyse them from their ends.
You will be able to
Syllabus learning outcomes: 2.2.1, 2.2.2, 2.2.3, 2.2.4, 2.2.5, 2.2.6, 2.2.7, 2.2.8
· Join fatty acids to glycerol by ester bonds, compare saturated and unsaturated chains, then shake triglycerides and phospholipids into water.
Join fatty acids to glycerol by ester bonds, compare saturated and unsaturated chains, then shake triglycerides and phospholipids into water.
You will be able to
Syllabus learning outcomes: 2.2.3, 2.2.9, 2.2.10, 2.2.11
· Join amino acids by peptide bonds, build up four levels of protein structure, heat a protein, and compare haemoglobin with collagen.
Join amino acids by peptide bonds, build up four levels of protein structure, heat a protein, and compare haemoglobin with collagen.
You will be able to
Syllabus learning outcomes: 2.3.1, 2.3.2, 2.3.3, 2.3.4, 2.3.5, 2.3.6, 2.3.7, 2.3.8
· Link polar water molecules and hydrogen bonds to dissolving ions, warming slowly and cooling by evaporation, using a labelled conceptual reference liquid.
Link polar water molecules and hydrogen bonds to dissolving ions, warming slowly and cooling by evaporation, using a labelled conceptual reference liquid.
You will be able to
Syllabus learning outcomes: 2.4.1
· Test unknown samples with Benedict's, iodine, biuret and the emulsion test, standardise a semi-quantitative Benedict's test, and detect a non-reducing sugar.
Test unknown samples with Benedict's, iodine, biuret and the emulsion test, standardise a semi-quantitative Benedict's test, and detect a non-reducing sugar.
You will be able to
Syllabus learning outcomes: 2.1.1, 2.1.2, 2.1.3, 2.2.4, 2.2.6
Each link is a piece of biology that carries an idea from one lab into another. Follow one to use what you found here in a new setting.
A single base substitution in the HBB gene changes one codon. Follow it through the protein and the phenotype to inheritance and a genetic test.
The codon GAG becomes GTG. What type of mutation is this, and what changes in the polypeptide?
A substitution, and a missense one: one amino acid (glutamic acid) is replaced by another (valine); the reading frame is not shifted.
Why can one amino acid change alter how haemoglobin behaves?
The new R group is non-polar, so it changes the interactions on the molecule's surface: at low oxygen the molecules stick together into fibres that distort the red blood cell.
Which phenotype does a person with two copies of the allele have?
Sickle cell anaemia: the HBB gene codes for β-globin, the altered β-globin gives abnormal haemoglobin and sickled cells.
Two parents each carry one copy (HbᴬHbˢ). What is the probability that a child is HbˢHbˢ?
0.25 for each child, independently: the Punnett square gives 1 HbᴬHbᴬ : 2 HbᴬHbˢ : 1 HbˢHbˢ as expected proportions, not a guaranteed family pattern.
A test amplifies the region by PCR and cuts it with a restriction enzyme whose site the mutation removes. How would the gel show the allele?
The normal allele is cut into two shorter fragments, which travel further towards the positive electrode; the sickle allele stays one longer fragment, so a carrier shows both patterns.
