4th yr Flashcards
what is photosynthesis
an endothermic reaction that plants carry out to gain energy
what is the word equation for photosynphesis
carbon dioxide + water = glucose + oxygen
what is the balanced symbol equation
6CO2 + 6H2O = C6H12O6 + 6O2
what factors affect photosynthesis
- carbon dioxide concentration
- light intensity
- temperature
how does the carbon dioxide level concentration affect the rate of photosynthesis
plants need carbon dioxide to make glucose and as the carbon dioxide levels rise the rate of photosynthesis also rises
how does light intensity affect the rate of photosynthesis
the brighter the light the more energy the plant has so the rate of photosynthesis increases
how does temperature affect the rate of photosynthesis
an increase in temperature causes enzymes to work faster so an increase in temperature causes the rate of photosynthesis to increase until around 40-50°C when the enzymes start to denature and the rate of photosynthesis decreases
how are leaves adapted for photosynthesis
- large surface area allowing for large amounts of sunlight energy
- thin so small distance for diffusion
- air spaces to allow carbon dioxide to be absorb
- guard cells open and close stomata to allow for gas exchange
what ions are needed for chlorophyll
magnesium
what ions are needed for amino acids
nitrate ions
how is the structure of a leaf adapted for gas exchange
. thin so short distane for diffsuion
. large surface area
. air spaces in spongy mesophyll cells
. many stomata to allow gas to move in and out the leaf
.
what is the role of the stomata in gas exchange
found between guard cells and opens allowing water to enter the leaf causing it to become turgid,
. this allows for gases to diffuse in and out of the lead
. stomata then close to prevent diffusion out of the leaf
why do plants need transport
to exchange substance’s such as food molecules
what is the phloem
distrubtes sugars and amino acids around the plant
what does the xylem do
moves water and minerals up the roots to the shoots
how is water absorbed by root hair cells
. water moves into the root hair cells by osmosis and into the xylem
what is transpiration
the evaporation of water from the surface of a plant
what does blood consist of
red blood cells , white blood cells , platelets and plasma
what is plasma used for
- carbon dioxide - it dissolved in the plasma and is transported from the respiring cells to the lungs
- digested food and mineral ions - dissolve particles are delivered to requiring cells
- urea - dissloves in plasma and is transported to the kidneys
- hormones - released by glands into the blood dissolved in plasma and delivered to the targeted organs
how are red blood cells adapted for transport of oxygen
- full of haemoglobin that binds to oxygen
- no nucleus allowing for space for haemoglobin
. biconcave shape that allows for a large surface area to volume ratio
how does the immune system fight infection
- as the pathogen enters the body
- the immune system triggers and release phagocytes that engulf and digest the
pathogen - the immune system also produces lymphocytes that are anti-bodies that destroy and engulf pathogens
how do vaccination work
- a harmless version of a pathogen is injected into the body
- which triggers immune system to release lymphocytes to destroy the pathogen
- as it destroys the pathogen the lymphocytes produce anti-bodies
- the memory cells then remember the pathogen and are able to release anti-bodies quicker when a stronger and more harmful version of the pathogen is to enter the body
what do platelets do
platelets release chemicals that cause red blood cells to become trapped causing a clot which dries to form a scab
what is structure of the heart
- deoxygenated blood enters the heart through the vena cava to the right atrium into the right ventricle
- the blood then travels to the pulmonary artery into the lungs where it is oxygenated via gas exchange
- oxygenated blood then leaves via the pulmonary vein to the left atrium into the left ventricle which pumps the high pressured blood all around the body
- as the blood travels around the body the oxygen is diffused to muscles that require it and return to the lungs to be oxygenated
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what is coronary heart disease
when layers of fatty material build up inside the coronary artery which can cause a heart attack
what are the 3 main types of blood vessels
arterys
veins
capillaries
what are key features of an artery
. carry blood at high pressure away from the heart
. carry oxygenated blood
. thick muscular walls
. narrow lumen
what are key features of veins
. carry blood at low pressure towards the heart
. carry deoxygenated blood
. thin walls
. contain valves that prevent backflow
. large lumen
what are key features of the capillaries
. carry blood at low pressure in tissues
. carry both oxygenated and deoxygneted blood
. cell walls are once cell thick
. narrow lumen although layer of muscle around
how is blood carried around the body
- oxygenated blood is carried away form the lungs into the heart by the pulmonary veins
- the aorta then carried blood to the arteries which take oxygenated blood to rest of the body
- then deoxygenated blood is taken by the renal vein into through vena cava into the lungs via the pulmonary artery
what are the waste products for plants
. carbon dioxide
water vapour
oxygen
how is carbon dioxide excreted out of a plant
via the stomata by diffusion
what are the organs of excretion
lungs - carbon dioxide
kidney - urea
skin- salt and water
how does the kidney excrete
by osmoregulation which is the when the body maintains its water and salt concetration
- the kidneys regulate water content
- the excrete toxic waste products of metabolism
what is the strcutre of the urniary system
. kidney - filter blood
. ureter - tube that connects kidney to bladder
. bladder - stores urine produced by the kidney
. urethra - tube that connects to the bladder, allowing for excretion of urine
what does the kidney consist of
- cortex
- medulla
- renal pelvis
what does the nephron consist of
- bowmans capsule
- convulated tubele
- loop of Henle
- collecting duct
what is ultrafiltration
a process in the kidney by which urea, salt, water and glucose is extracted from the blood.
what happens in ultrafiltration to form urine
- the high pressured blood in the bowmans capsule filters out, urea glucose, water and salts
- the blood then enters the convoluted tubule, where selective reabsorption occurs and substances such as glucose, salts
- then urine is left to be transported to the collecting duct where water is reabsorbed by osmosis and urine is excreted
how does ADH control the water content in blood during selective reabsorbtion
if the water content of the blood is too high than less water will be reabsorbed but if the water content in the blood is too low then more water is reabsorbed
AS ADH AFFECTS THE PERMIABILITY OF THE TUBULES
what is homeostasis
where organism maintain there internal enviroment
why is homeostasis important
it helps an organism stay healthy and maintain optimum conditions to function
what do all co-ordinated repsonses require
. a stimulus - change in environment
. receptor - detects stimuli
. coordination centre - such as brain where info is processed
. effector - such as muscles which restores optimum levels
what is a geotropic repsonse of a plant
a response to gravity such as growing upwards
what is a phototropic response of a plant
growing towards light
what are the two types of control systems in a human
. nervous system
. hormonal system
what is the nervous system
- sends signal via electrical impulses
- impulses travel along nerve cells
- rapid responses
what is the hormonal system
- sends signal in chemical form
- travel through blood
- do not need instant responses
- produced by endocrine glands
what does the human nervous system consist of
CNS (brain and spinal cord)
nerves
how does the human nervous system work
- a stimulus is recognised by the sensory neurone
- the sensory neurone sends electrical impulses to the CNS which passes it on the relay neurone
- the relay neurone then sends impulses to the motor neurone which carries these signals until they reach the effector which carries out the response
what is a neurotransmitter
a chemical that transfers a signal from one neurone at the synapse to another
how do neurotransmitter work
an electrical signal is converted to a chemical and is diffused from one synapse of a neurone to another to send a signal
what is a reflex response
a rapid response that does not involve the CNS
what are advantages of a reflex response
rapid
automatic
what is the structure of the eye
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what does the cornea do
transparent and allows light to enter the eye
what does the iris do
control amount of light entering the eye
what does the lens do
changes shape in order to focus light onto retina
what does the retina do
contains light receptors and detects colour
what does the optic nerve do
carries impluses from the eye to the brain
what does the pupil do
allows light into eye
what does the conjunctiva do
covers the white area of the eye and provides protections and lubricant
what does the cillary muscles do
contracts and relaxes to change shape of eye depedning on light intensity
what does the suspensory ligaments do
connect the cillary muscles to the eye
what happens when an object is close in the eye
- the ciliary muscles contract
- the suspensory ligaments loosen
- light is refracted more
what happens when an object is far away in the eye
- the cilary muscles relax
- the suspensory ligaments tighten
- less light is refracted
what happens in bright light in the eye
- the circular muscles contract
- radial muscles relax
- pupil constricts
what happens in dim light
- the circular muscles relax
- the radial muscles contract
- pupil dilates
what is vasodilation
when the body supplies capillaries with lots of blood to cool down via radiation
what is meant by the terms population
a group of organisms of the same species in the same place
what is meant by a community
a group of populations of organisms living in the same area
what is meant by a habitat
a place or location an organism lives
what is meant by an ecosystem
the total biotic factors and non biotic factors within an area at one time
what is a producer
an organism that create its own food using sunlight energy
what is a primary consumer
an organism that eats the producer in order to gain energy
what is a secondary consumer
an organism that eats the primary consumer in order to gain energy
what is a tertiary consumer
an organism that eats the secondary consumer in order to gain energy
what is the carbon cycle
where carbon is recycled through ecosystems
what are the stages of the carbon cycle
- carbon is taken out of the atmosphere by plants due to photosynthesis
- plants then use the carbon to make glucose
- animals then eat the plants and respire
- as the animal respire carbon dioxide is released into the atmosphere
what is the nitrogen cycle
where nitrogen is recycled through ecosystems
what are the stages
- nitrogen is transported to the soil via nitrification such as lightning
- nitrogen fixing bacteria in the soil then converts to nitrates
- plants absorb nitrates to build protien
- animals eat plants and absorb protein
- decomposers then convert the nitrates into ammonia when animal excretes
- denitrifying bacteria convert ammonia into nitrogen and back into atmosphere
what can air pollution cause
- acid rain- sulphur dioxide
- carbon monoxide - binds to haemoglobin and prevents oxygen to travel through the body
what are greenhouse gases
they are gases that absorb the infrared ray from the sun causing them to be trapped in the atmosphere
what are the greenhouse gases
- methane
- carbon dioxide
- water vapour
- nitrous oxide
what can green house gases lead to
- ocean level rises
- increase temps so drought
- loss of habitat
