Biology paper 2 Flashcards
What is the balanced equation for photosynthesis?
6CO2+6H2O—>C6H12O6+6O2
Word equation for photosynthesis?
carbon dioxide+ water
–>glucose+oxygen
How do you test for how light can effect photosynthesis?
1)set up apparatus, empty gas syringe and add sodium hydrgen carbonate to esnure the plant has enough CO2, a source of white light is placed at a specific distance from the plant, leave for a set amount of time for photosynthesis to take place, see how far the gas syirnge has moved, then change the distance to closer and furtehr away to get more results, make sure you leave for the same amount of time and have the same temperature.
When light intensity increase will rate of photosyntheiss also increase?
they will both increase together up untill a certain point where light intensity will no longer effect the rate of photosynthesis.
what factors effect photosynthesis?
the amount of Carbo dioxide as too little will slow the reaction down, and temeprature also effects it as if to cold enzymes take longer to work and if too hot the enzymes will denature.
What is the role of root hairs in plants?
they take in minerals and water from the soil, there are million microscopic ones meaning there is a large surface area
What is the role of phloem tubes in plants?
they transport the food, they are made from elongated cells
What is the role of xylem tubes in plants?
they take water up, made from dead cells, carry the water and minerals from the roots to stems and leaves
What is the process of transpiration?
transpiration is caused by evaporation and diffusion, mainly in the leaves, , thsi creates water loss so the xylem brings up more water, this means tehre is a cosntant water transport and carry of minerals which are in the water
What are and what do are stomota needed for?
Stomato are tiny pores on the surfaces of plants and they are needed for gas exchange, the allow oxygen abd carbon dioxide to diffuse directly into the leaves, as well as for water vapour to leave during transpiration.
What environmental factors affect transpiration rate?
light intesnity brighter light means greater transpiration rate, temperature the warmer it is the fats it occurs and air flow better air flow also increases transpiration rate,
What is in a leaf?
The wacy cuticle, xylem and phloem, upper epidermis, stomata, guard cells, lower epidermis, air space, spongy mesophyll tissue, palisade mesophyll tissue.
what does the palisade layer in a plant do?
contains lots of chloroplasts
what does the upper epidermis do?
it is transparent so light can pass through and go to the palisade layer.
what are some adaptions plants have for harsh environments?
small leaves or spines - reduces surface area for water loss by evapouration, spine salso prevent animals eatng the plant. curled leaves or hairs reduce airflow. thick waxy cuticles, reduce water lost by evapouration. thick fleshy stems store water, fewer stomata or stomata that open at night reduce water loss by evapouration
what are and what do auxins do?
they are plant growth hormones, they grow at tips of shoots and roots encourage shoot growth but not root growth. they also make the plant change shape to bend towards sunlight.
What are 6 ways that plant hormones can be used for commercial use?
selective weed killers, growing from cuttings with rooting powder, controlling flower and fruit formation, producing seedless fruits, controlling the ripening of fruits, controlling seed germination
What is the pituitary gland where is it and what does it do?
it is located in the brain, called the master gland and produces hormones to regulate body conditions.
What is the thyroid gland where is it and what does it do?
it is in the neck, produces thyroxine which is used to regulate metabolism rate, heart rate and temperature,
What is the adrenal glands where is it and what does it do?
produces adrenaline near pancrease, kicks in the fight or flight response
What is the testes where is it and what does it do?
in the testicals, produces testosterone, controls puberty and sperm production,
What is the ovaries where is it and what does it do?
produces oestrogen involved in menstrual cycles
What is the pancreas where is it and what does it do?
produces insulin to regulate blood glucose levels.
How does adrenaline work?
binds to sepcific receptors in the heart meaning it contracts more frequently and with more force, increasing heart rate and blood pressure, increasing oxygen and glucose going to the muscles, also binds to receptors in liver making glycogen break into glucose, increase blood glucose levels.
How does the body control hormone levels.
It uses negative feedback which helps detect when a substance is too high or low allowing the body to recat and bring the level back to normal.
How does negative feedback keep the right thyroxine level?
when lower then normal the hypothalamus is stimulated to release TRH, this makes the pituitary gland release TSH, which makes the thyroid gland release thyroxine when higher TRH production inhibited so amount of TSH decrease so less thyroxine is released.
how many stages are in a mnestrual cycle and what are they?
4 stages,
stage 1 menstruation starts
stage 2 uterus lining is repaired,
stage 3 an egg develops and is released
stage 4 lining is maintained
what are the 4 hormones used during menstruation?
FSH - released by pituartity gland and causes a follicle to mature in one of the ovaries this stimulates oestrogn production
Oestrogen - released by ovaries this causes the uterus to thicken and grow, and a high level stimulates LH surge.
LH - released by pituitary gland, the surge causes the egg to release,, stimulates the remains of the follicle to develop into a structure called a corpus luteum, this secretes progesterone.
progesterone - released by the corpeus luteum after ovulation, maintains uterus lining and inhibits FSH and LH, when progesterone level falls the uterus lining breaks down, this allows FSH to increae and restart the cycle
what are the different steps during a menstrual cycle?
day 1- 4 lining of uterus breaks
day 4-14 lining of uterus builds up.
day 14-28 lining of uterus is maintained
day 28-1 lining begins to deteriorate
What is chlomifene?
It is a therapy that involves giving them the drug so that they can have an increase in FSH and LH so that they ovulate more regularly and encourage egg maturation. by knowing when the women will ovulate the couple can have intercourse during this period
what is IVF?
collecting eggs from womens ovaries and fertilising them in a lab using the mans spem. these get grown into embryos once they become tiny balls of cells on or two are transferred into the womens uterus to improve chance of pregnancy.
What types of contraceptions can be used to prevent pregancy?
Hormones - oestrogen can prevent release of egg as if high level kept egg won’t release, progesterone reduces fertility, produces thick mucus preventing sperm to reach egg this can be done by a pill. or a condom can be used so that a barrier prevents the sperm and egg from ever meeting.
What is homeostatis?
the maintaining of a constant internal environemnt - conditions in body neeed to be steady as your cells need the right conditions to work properly, can be dangerous once conditions vary too much.
What are 3 examples of homeostatis action?
Osmoregulation - keep a balance between water you drink and water you pee, sweat and breathe out,
thermoregulation - reduce your body temperature when you are hot but increase when cold
blood glucose regulation - need to make sure amount of glucose in blood doesn’t get too high or too low.
What happens when blood glucose is too high?
Insulin gets added either by injection if you have diabetes or is secreted from pancreas, the blood with too much glucose and insulin enters the liver where the insulin converts the glucose into glycogen
What happens when blood sugar levels are too low?
blood with too little glucose is detected by pancreas, this time it secrets glucagon, this goes round the blood strem to the liver, the glucagon and too little glucose blood enters the pancreas where it converts the glycagon in the liver to glucose which is the secretd out.
What is type 1 diabetes caused by?
A lack of insulin, this is because the pancreas secrets little to no insulin meaning a person glucose levels can rise to a level it could kill them, so they inject insulin into their blood stream (mealtimes) so glucose can be quickly removed from blood once food has been consumed. as well as this they alo need to be careful of foods rich in simple carbs like sugar and regularly exercise
what is type 2 diabetes caused by?
When a person is resistant to insulin, pancreas doesn’t produce enough or the person becomes resistant to insulin, tehre is a correlatin between obesity and type 2 diabetes.
