Weak Areas In Homeostasis + inheritance variation Flashcards
bacterial toxin into a plant
-use enzymes to remove the gene for the toxin from the DNA of bacteria
-add gene into cells of tomato plant
+it is added to plant cells DNA or chromosomes
what two hormones control blood glucose levels?
-insulin and glucagon
what happens when blood glucose levels are too low?
-glucagon is released, converting glycogen back into glucose
what is the main function of the kidneys?
-to filter waste from the blood and maintain water and ion balance
what process removes waste substances from the blood?
-filtration
what is selective reabsorption?
-the process where useful substances like glucose and some ions are reabsorbed into the blood
how is urine concentration controlled?
-by the hormone ADH which regulates water reabsorption in the kidneys
what is selective reabsorbption?
-the process where useful substances like glucose and some ions are reabsorbed into the blood
how does dialysis work?
-it filters waste and excess substances from the blood using a machine
why can kidney transplants be rejected?
-the immune system may attack the donor kidney, though drugs reduce this risk
what is an advantage of a kidney transplant over dialysis
-it is a long-term cure and eliminates the need for regular dialysis sessions.
what is thermoregulation?
-the process of maintaining a constant body temperature around 37 degrees
what is the thermoregulatory centre located, and what does it do?
-the brain and contains receptors that detect blood temperature.
-it also receives information from the temperature receptors in the skin
what are the body’s responses when it gets too hot?
-blood vessels dilate - more blood flows to the capillaries near the skin’s surface, increasing heat loss
-sweat is produced which evaporates from the skin, increasing heat loss.
How does the body respond when it is too cold?
-hairs stand up, this traps an insulating layer of air
-no sweat is produced, this reduces heat loss
-blood vessels constrict , less blood flows to the capillaries near the skin’s surface, reducing heat loss
-shivering - muscles contract automatically, generating heat and releasing energy
what happens when the body is exposed to extreme cold for a long time?
-blood supply to fingers and toes is cut off to reduce energy loss, but this can kill the cells, leading to frostbite
describe the process of genetic engineering
-a useful gene is isolated by being cut from one organism’s genome using enzymes and is inserted into a vector
-the vector is usually a virus or a bacterial plasmid depending on the type of organism that the gene is being transferred to
-when the vector is introduced to the target organism, the useful gene is inserted to its cells
what is reaction time?
-the time it takes to respond to a stimulus, usually less than a second
what factors can affect reaction time?
-age, gender , drugs e.g caffeine
how can reaction time be measured using a rule?
-the person being tested places their arm on a table
-a ruler is held vertically between their thumb and forefinger
-the tester drops the ruler without warning
-the person catches the ruler as quickly as possible
-the test is repeated and the mean is calculated
what must be controlled in the ruler test to ensure fair results?
-use the same person and same hand each time
-drop the ruler from the same height
-ensure the person has not consumed caffeine before the test
how can computers be used to measure reaction time?
-the person clicks the mouse as soon as the see a stimulus on the screen
-computers provide more precise measurements by removing human error
-results are recorded in milliseconds, making them more accurate
-computers prevent the tester from predicting the stimulus, unlike the ruler test
