practicals Flashcards
describe the test for starch
-add a few drops of iodine to the substance
-if it contains starch it will change from orange to blue-black
describe the test for lipids
-add ethanol to the substance
-leave it for one minute
-it will turn from colourless to cloudy
describe the test for proteins
-add copper sulfate solution
-changes from pale blue to purple
what is the test for glucose?
-add a few drops of Benedicts solution
-colour change from blue to orange-red
what are the two types of sampling? describe them
-non-random sampling - samples are taken at predetermined points
-random sampling - samples are taken at random
what breaks down starch
amylase breaks down starch into glucose
what breaks down protein
protease breaks down proteins into amino acids
what breaks down fats?
lipase breaks down fats into fatty acids and glycerol
describe two ways to take the rate of photosynthesis
-count the number of oxygen bubbles
-measure the time taken to produce a fixed amount of gas
how can you identify which bacteria you have in a culture
-overall size and shape
-the texture of its edges and surfaces
-elevation above the agar
-transparency and colout
how do you measure the zone of inhibition
the area that is clear of any bacterial growth around a point
what is the acronym for mitosis?
IPMAT
describe interphase
the DNA in the cell replicates to form 2 copies of each chromosome
describe metaphase
-nuclear membrane breaks down
-chromosomes line up across the centre of the cell
describe anaphase
one set of chromosomes is pulled to each end of the cell and the nucleus
what is telophase
membranes form around each end of the cell
what is the outer layer of the kidney called?
the cortex
what is the inner layer of the kidney called?
the medulla
what is the function of the ureter and where it is located?
-carries urine from the kidneys to the bladder
-in the kidney, it is in the middle
where are the nephrons located?
they start in the cortex, loop down into the medulla and back to the cortex
describe the bowman’s capsule
surrounds a ball of capillaries called the capillary knot
describe ultrafiltration
-high pressure is created in the capillary knot by the diameter of the capillary leaving the knot being narrower than the capillary entering
-ultrafiltration - small molecules pass out of the capillary and into the bowman’s capsule (waste products)
-proteins and blood cells are too big to leave the capillaries to go into the tubule
where is insulin produced?
the pancreas
when is insulin released?
high blood glucose levels
what is the function of insulin?
-triggers cells to absorb glucose from the bloodstream
-converts glucose to glycogen
when is glucagon released?
when blood glucose levels are low
what is the function of glucagon?
-breaks down glycogen in the liver into glucose
-releases glucose into the bloodstream
describe the general structure of negative feedback loops
-stimulus: initial change in the body’s condition
-receptor: detects the change
-control centre: processes the information
-effector: takes action to reverse the change
what does thyroxine control?
-regulates metabolic rate
-controls body temperature
what does ADH control?
-water content of blood
what is the effect of increased levels of ADH?
increases reabsorption of water by the collecting ducts
when is ADH released?
released from the pituitary gland when blood is too concentrated
what is the effect of adrenaline?
-increases breathing rate
-increases heart rate
increases flow of blood to muscles
-converts glycogen to glucose
where is adrenaline released from?
the adrenal glands
which organ does insulin do its work in?
liver
what happens when thyroxine levels are low?
-hypothalamus releases TRH
-pituitary gland releases TSH
-thyroid releases more thyroxine
what happens when thyroxine levels are normal?
-TRH release from hypothalamus is inhibited
-this inhibits the release of TSH from the pituitary gland
what do oestrogen and progesterone control?
the menstrual cycle
what do FSH and LH control?
fertility
what are the effects of oestrogen?
-released from the ovaries
-uterus lining grows
what are the effects of progesterone?
-produced by the empty follicle in the ovary after the egg has been released
-maintains lining of the uterus
what does FSH stimulate?
-oestrogen production
-the growth of follicles in the ovary
-secreted by the pituitary gland
describe LH
-secreted by the pituitary gland
-stimulates ovulation
what does progesterone inhibit?
FSH + LH
what does oestrogen stimulate?
LH
what hormones do fertility drugs contain?
FSH + LH
what happens when the eye needs to focus on a nearby object?
-ciliary muscles contract
-suspensory ligaments loosen
-lens becomes fatter
what happens when the eye needs to focus on a distant object?
-ciliary muscles loosen
-suspensory ligaments tighten
-lens becomes thinner
what does thyroxine do?
-stimulates exothermic reactions
what is needed for Benedict’s solution to work?
heat
