Biology: Topic 8

Question 1

Parkinson’s Disease

Answer 1

Caused by a lack of dopamine

Question 2

MAO Inhibitors

Answer 2

MAO’s are enzymes that break down neurotransmitters after they have been used. Dopamine/serotonin is not broken down so there are increased amounts of the neurotransmitter.

Question 3

L-Dopa

Answer 3

This travels through the blood into the brain and is able to pass through the ‘Blood Brain Barrier’. Once in the brain, it converts into dopamine.

Question 4

Dopamine agonsit

Answer 4

This mimics dopamine, by having a similar shape and structure to bind to receptors on the post synapse and cause an action potential to travel down the nerve.

Question 5

Gene therapy

Answer 5

Increase the production of enzymes that are involved in the production of dopamine, thus increasing the production of dopamine. More cells can also be triggered to divide and form more nervous connections, however this carries a risk of developing cancer.

Question 6

Deep brain stimulation

Answer 6

This treats the symptoms of the disease, allowing patients to reduce their intake of medication.

Question 7

SSR inhibitors

Answer 7

SSRs are involved in the re uptake of serotonin from the synapse. If these are inhibited, then there is more serotonin in the synapse to increase the chance of impulses being created.

Question 8

Depression

Answer 8

Caused by a lack of serotonin

Question 9

Schwann cells/Myelin sheath

Answer 9

Fatty layer wrapped around the axon to increase the speed of the impulse.

Question 10

Node of ranvier

Answer 10

The gap between schwann cells.

Question 11

Thalamus

Answer 11

The thalamus is located near the centre of the brain, between the two hemispheres. Here, information arriving to the brain is sent to it’s relevant region for processing.

Question 12

Hypothalamus

Answer 12

The hypothalamus regulates body temperature, as well as sleep, thirst and hunger. It is also an endocrine gland which secretes anti diuretics, as well as attaching to the pituitary gland, which secretes a number of other hormones.

Question 13

Cell elongation

Answer 13

Auxins bind to receptors, trigger secondary messengers (transcription factors). Proton pumps are synthesised, more protons in the cell wall and vacuole. Cell wall becomes acidic and expansins (enzyme) causes myofibrils to separate from cross linking polysaccharides. Vacuole fills with water (osmosis) and cell elongates. Expansins deactivate and cell wall reforms bonds, thus retaining the cells new shape.

Question 14

Phytochromes

Answer 14

A photoreceptor found in plants, made up of a protein and a light absorbing pigment group. There can be five different types of phytochromes, each with a different protein.

Question 15

Pr

Answer 15

Pr(660) is synthesised by plants, it is then converted into it’s active form, Pfr, during daylight (red light).

Question 16

Pfr

Answer 16

Pfr(730) is converted back to Pr at night (darkness or far red light). Different concentrations of Pfr will stimulate germination, flowering and greening.

Question 17

CAT scan

Answer 17

Uses X-rays to produce a cross-sectional image of the brain.

Question 18

PET scan

Answer 18

Radiotracers incorporated into glucose and water are entered into the bloodstream and emit positrons as they decay. Areas of the brain that work harder receive more. Positrons colliding emit gamma rays which is picked up by detectors.

Question 19

MRI scan

Answer 19

Energy released by hydrogen nuclei in the brain caused by radio waves and magnetic fields are detected by a computer and produced into an image.

Question 20

fMRI scan

Answer 20

Radio waves either reflected or absorbed by oxyhaemoglobin in the blood, used to form a computer image.