What are the two major biochemical components present in all viruses (1)
*Proteins
* nucleic acid / RNA / DNA
Describe the biochemical structure of a glycoprotein (2)
- (globular) protein
- with a carbohydrate attached to it
Describe how the ebola virus enters the host cell via cell membrane (3)
- binds to receptor / protein
*phagocytosis / endocytosis / pinocytosis - Cell membrane engulfs the virus in a vesicle
Why is it not possible to use a standard curve determined by colourimeter for glucose determination in whole blood sample (1)
- blood is coloured so it could not get a colorimeter reading / light cannot pas through
Give two advantages of using immobilized enzymes for blood glucose monitoring in biosensors (2)
- only glucose will give a result / enzyme specific to glucose
- detects very low concentration
- reading is more accurate enzyme is more stable
- works at different temperatures
What would be the products of a condensation reaction between glucose and galactose (1)
- lactose and water
Explain why there is no decrease in mass at any sucrose concentrations when sweet potato is used instead of potato (1)
- sucrose has a very high sugar concentration
Describe how you could modify the method to determine the water potential of sweet potato (2)
- increase the sucrose concentration
- a wider range of sucrose concentrations
- where water will flow out of the potato
Explain why the indicator turns pink to colourless when lipase is added to milk in an experiment (3)
- hydrolysis of lipids
*causing production of fatty acids - fatty acids cause the milk to become more acidic changing it to colourless
Why would the milk and lipase experiment not be suitable for assessing the effect of different pH values on lipase (1)
results depend on pH change in test tube so cannot change pH of experiment
Explain why it is important that the RNA which is finally translated consists only of exons (2)
- introns do not code for the primary structure of a protein
- if introns are included there would be a different protein structure produced
Explain how a change in sequence of base in DNA of the gene (a mutation) would effect the protein produced if it was in an intron and an exon (2)
- intron - no effect
may change amino acid sequence in polypeptide chain
Describe the significance of meiosis and mitosis and explain the cells produced by the process and how mitosis can form a tumour (9)
mitosis
* daughter cells are genetically identical
* growth
repair from damage and disease
* repeated cell renewal
* maintains chromosome number
Meiosis
*produces non identical daughter cells
* gamete production
* raw material for survival of the fittest
*sexual reproduction for environmental changes / disease
*crossing over in prophase 1 and random assortment - genetic variation
haploid cells produced so at fertilisation diploid cell is regained
tumour formation
* genetic change allow mitosis change in unrestricted ways
*solid mass of cell prevent normal cells from functioning
* benign malignant
* cell division stops after meiosis
