Paper 3 Flashcards
(16 cards)
Explain how molecular phylogeny would have been use to create the evolutionary tree of mammals
Comparing differences in DNA/proteins between different mammal species
To show their evolutionary relationships
Show how closely related species are
Torpor involves reduction in body temperature. Describe how thermoregulatory mechanisms could bring about a decrease in body temperature?
Thermoreceptors detect
Thermoregulatory centre in hypothalamus is stimulated
Sends impulses to swear glands
Increase sweat production
Vasodilation to increase blood flow to skin
Constriction of shunt vessels
Metabolic rate decreases to reduce heat production
Why is it easier for smaller mammals to decrease body temperature more significantly than larger animals?
Smaller organisms have larger surface area to volume ratio
Lower metabolic rate if temperature not maintained
Lose heat faster as there is a shorter distance for radiation
Explain what could cause “change in the level of gene products” in cells from the same tissue during torpor stage
All cells in tissue receive the same stimulus
This can deactivate or activate gene expression
If genes are activated, mRNA will be produced
What is meant by genome
All the genetic information in an organism
Explain why high blood pressure increases risk of developing CVD
Damage to endothelium
Inflammatory response leads to atheroma formation
Plaque build up narrows lumen of arteries reducing blood flow
Two current method to reduce high blood pressure
Take anti hypertensive drugs like beta blocker
Reduce salt intake in diet
Quit smoking
Explain why exposure to cosmic radiation can cause mutation
Damages DNA
Changes base sequence
Why lowering body temperature to 32 degrees would decrease metabolic rate in body
Lower temperature lowers kinetic energy of enzyme and substrate molecules
Fewer successful collisions so fewer enzyme-substrate complexes form
This slows rate of metabolic reactions including respiration
Explain how caffeine activates neurones with adenosine receptors causing feelings of alertness
Caffeine has similar shape to adenosine so it can bind to receptors
Causing sodium channels to open and sodium ions to diffuse into post synaptic neurons
Causing depolarisation of post synaptic Borland
If threshold level is reached , an action potential is triggered in neurone
Ethical issues relating to use of rats and pigs in experiments
For:
Benefit of research, e.g. helping human health are greater than harm done to animals
Regulations means animals must be treated well
Against:
All animals have rights just as much as humans
Work on animals may not be applicable to humans
Computer models can be used instead
Name another part of the brain that controls automatic bodily processes
Medulla oblongata
Explain how hypothalamus can coordinate raphe pallidus to decrease neutral activity
Sends impulses along parasympathetic nerves to decrease frequency of action potentials
Explain how change in gene expression could slow down rate of cell division
If expression of a gene that codes for a protein involved in regulating the cell cycle is changed
Could inhibit cells passing checkpoints in the cell cycle
Cell cycle lengthened or inhibited by checkpoint proteins e.g. from tumour suppressor genes
Explain how lysosomes work to break down and remove debris from the cell
Lysosomes fuse with vesicles containing debris and enzymes hydrolyse the molecules
Lysosomes or vesicle fuse with the cell surface membrane releasing contents
Explain how environmental factors could result in epigenetic control of neurone cell activity
Acetylation of histones causes DNA to unwind and allows RNA polymerase to bind
DNA methylation can affect transcription of genes
These can change gene expression in neurones
