Studied by 6 peopledosnt include labelling of the heart for that visit :https://www.geoguessr.com/vgp/3805
whats diffusion
the movement of particles from a higher to a lower concentration
how does increasing the temperature affect diffusion
the rate of diffusion increases as particles have more kinetic energy and move faster
how does the surface area of the membrane affect diffusion
as surface area increases so does the rate of diffusion as there is more space for the particles to move through
whats a concentration gradient
occurs when the concentration of particles is higher in one area than another- like a gradient/slope of concentration
what does it mean when somethings against a concentration gradient
moving from an area of low concentration to an area of high concentration ( like going uphill)
what does it mean when somethings going down a concentration gradient
moving from and area of high concentration to an area of low concentration (like going downhill)
how does the concentration gradient affect the rate of diffusion
the bigger the concentration gradient, the faster the rate of diffusion
in what substances does diffusion happen
in liquids and gases
what are the 3 ways substances can move in and out of cells
diffusion
active transport
osmosis
whats active transport
movement of particles across a membrane from a lower to a higher concentration - against a concentration gradient using ATP released during respiration
what are the differences between active transport and diffusion
active transport requires energy from respiration as it is working againt the gradient , diffusion dosn’t
active transport is against the concentration gradient whereas diffusion is down a concentration gradient
whats an example of active transport in the digestive system
substances such as glucose from your food have to move from your gut to your bloodstream
sometimes there can be a lower concentration of sugar molecules in the gut than the blood meaning diffusion cant take place
active transport is required to move the sugar to the blood against its concentration gradient
whats a partially permeable membrane
a membrane with very small holes in it to allow small molecules through but larger molecules cant pass through
whats osmosis
the movement of water molecules across a partially permanent membrane from an area of higher water concentration to an area of lower water concentration
what kind of molecule can diffuse through cell membranes
small molecules e.g. glucose, amino acids water and oxygen
big molecules e.g. starch and proteins cant fit through the membrane
whats water potential
the potential (likelihood) of water molecules to diffuse out or into a solution
what does it mean of you have high water potential
you have a high concentration of water molecules
true or false - water can pass both ways across a membrane during osmosis
true - water molecules move about randomly all the time
what are turgid cells
cells full of water by the process of osmosis
explain how plant cells become turgid
watering plant increases water potential of soil around it
plant cells draw in water through osmosis to become turgid
what happens in a plant cell if there’s no water in the soil
the plant starts to wilt
the cells become flaccid - start to loose water
whats mitosis
when a cell reproduces itself by splitting to form two identical offspring
what are the 5 main stages in the cell cycle of mitosis
Cellular growth - the cell gets larger and produces more sub-cellular structures, such as mitochondria and ribosomes.
DNA replication - chromosomes duplicate, so that each consists of 2 arms (copies).
More cell growth.
Mitosis - the DNA divides into two.
Cytokinesis - the cell divides into two.
what happens during mitosis
the cell has 2 copies of itself spread out in long strings
the dna forms x shapes chromosomes (each arm is the exact copy of the other)
the chromosomes line up at the centre of the cell and cell fibres pull them apart to opposite sides of the cell
what happens during the division (cytokines)
membranes form around each of the 2 new sets of chromosomes - they become the nuclei
cytoplasm divides
produced 2 daughter cells genetically identical to each other + the parent cell
how many chromosomes do humans have
46 (23 pairs)
what is cell differentiation
process by which a cell becomes specialised for its particular function
why do cells become specialised
perform specific functions / allow organisms to work efficiently
how is a sperm cell specialised
long tails ans stream lined heads to help them swim.
They also have lots of mitochondria to provide them with lots of energy.
has digestive enzymes in its head to allow it to break through the wall of the egg
how is a structure of a red blood cell specialised
biconcave shape for large surface area to absorb+ release oxygen
dont have a nucleus so can carry more oxygen
small and flexible so can pass easily through capillaries
how are nerve cells specialised to carry electrical impulses
have a long axon to transport the electrical impulses long distances
have branches connections at each end to join to other nerve cells, allowing them to pass messages around the body.
They have a fatty (myelin) sheath that surrounds them. The fatty sheath increases the speed at which the message can travel.
how are root hair cells specialised to take up water and minerals
Root hair cells are specialised to take up water (osmosis) and mineral ions (active transport) from the soil as they are found in the tips of rooys
have a large surface area due to root hairs for faster diffusion
Contain list of mitochondria which release energy from glucose during respiration to provide the energy needed for active transport
what are stem cells
undifferentiated cells which can develop into lost of different types of cells
what are the 2 key features of stem cells
they can divide by mitosis to form more cells
they can differentiate into specialised cells
where are stem cells present
embryos
adult animals
meristems in plants
what are embryonic stem cells
found in human embryos and have potential to turn into any type of cell
where are adult stem cells found
bone marrow
whats the difference between adult and embryonic stem cells
embryonic can differentiate into any type of cell
adult stem cells can only differentiate into a narrow range of specilaised cells (e.g. afult stem cells in bone marrow can only differentiate into speocfic types of bloos cells)
what are the uses of embryonic stem cells
can grow into any type of cell found in the body
all tissues and organs can be potentially regrown
however transplanted tissues and organs may be rejected by the patients immune system
difficult to obtain and store embryonic stem cells
what are the uses of adult stem cells
Adult stem cells are found only in specific areas of the body and can only develop into a limited number of cell types e.g. bone marrow, breasts and intestines.
however as from the same body, would not reject their own cells
why are stem cells so important
because they have the potential to develop into different types of cells in the body which can be used for development, growth and repair
what are meristems
only plant cells which divide by mitosis found in plant tissues that are continually growing - the roots and shoots.
whats the disadvantage of specialised cells
once theyre specialised, theyre onlt adapted to carry out 1 job
what are the 3 main factors affecting the movement of substances
surface to volume ratio
temperature
concentration gradient
how does the surface to volume ratio affect the movement of substances
rate of diffusion,osmosis or active transport is higher in cells with larger surface area to volume ratio
how does the concentration gradient affect the movement of substances
substances move in and out of the cell faster if theres a big difference in concentration between the inside and outside of the cell
of there are more particles on one side, there are more there to move across
why is diffusion quicker in a single celled organism
substances can diffuse straight into and out across the membrane as they only have to travel a short distance
they have a relativity large surface area to volume ratio which means they are able to exchange enough substance across the cell membrane to supply the volume of the cell
why is it more difficult to diffuse substances in multicellular organisms
its too slow as some cells are deep inside the organism meaning its a long way from them to the outer environment
larger organism have a low surface area to volume ratio meaning you cant supply enough substances through the small outer surface for the large volume organism
how do multicellular organisms exchnange substances
they cant do it through their outer membrane so have to use specialised exchange surfaces
what 4 substances are transported within organisms
oxygen in for respiration
co2 is transported out from respiration
dissolved food molecules from digestion
urea and waste products
whats a transport system
an efficient system to transport substances from organs to the cells that use them.
what are some examples of transport systems in animals
circulatory system and the digestive system
what are examples of transport systems in plants
xylem and phloem
how are exchange surfaces in specialised exchange organs adapted to maximise effectiveness
walls are thin so only have short distance to travel
large surface exchange area so lots of molecules can diffuse across at the same time
in animals have good blood supply to help maintain a concentration gradient
permeable membranes for substances which they need to exchange - allow to diffuse across
how are the lungs adapted for gas exchange
contain alveoli whihc have to exchange oxygen and carbon dioxide
large surface area
thin walls
a good blood supply
a moist lining for dissolving gases
how are villi adapted to exchange nutrients
small intestine contains villi dissolve food molecules from the digestive system are absorbed quicker into the blood
they have a single layer of surface cells which increase surface area - dissolved food molecules absorbed more wuickly inyo blood
have a very good blood supply to assist quick absorption
explain how the structure of a leaf allows gases to diffuse in and out of cells
leaves are broad so have a large surface area for diffusion
they’re thin which means gases only have to travel a short distance
air spaces inside the leaf lets gases move easily between the cells and increases the surface area increasing the chance of oxygen to get into cells
underneath of leaf covered in stomata through which carbon dioxide diffuses into leaf and water vapour diffuses out
describe the transport of water and mineral ions into a root hair cell
water is drawn into root hair cell by osmosis as there is usually a higher concentration of water in the soil than inside the plant
mineral ions move into the root hair cell by active transport since the concentration of minerals is usually higher in the root hair cells than the soil (otherwise minerals would diffuse out of the root hair cells)
how are root hair cells adapted to take in water and mineral ions
cells on plant roots grow into long hairs which stick out into soil
each branch of root covered in these microscopic hairs
gives plant big surface area for absorbing water and mineral ions from soil
how do you find the surface area of an object
the sum of all the areas of the faces
how do you find the surface area to volume ratio
you find the surface area and divide it by the volume
whats the double circulatory system
Two circuits carrying the blood from the heart to the lungs and back and from the heart to around the body and back
what are the advantages to mammals having a double circulatory system
returning blood to the heart after its picked up oxygen at the lungs means it can be pumped out around the body at a higher pressure
this increases rate of blood flow at the tissues (blood can be pumped around body faster) so more oxygen is delivered to the cells
important for mammals ad take up a lot of oxygen maintaining body temp
describe the route that of blood in a double circulatory system
blood flows into right atrium from vena cava
atria contracts pushing blood into the right ventricle
the ventricle contract forcing blood into pulmonary artery and out the heart
blood then flows into lungs through arteries and returns through the pulmonary vein
the oxygenated blood will then flow into the left atrium
atria contracts pushing blood into left ventricle
ventricle contract pushing blood into the aorta and out the heart
blood goes around body and returns through the vena cava again
what are the 3cdifferent types of blood vessels found in the circulatory system
arteries
capillaries
veins
what do arteries do
carry blood away from heart
how are arteries adapted to their function
heart pumps blood out at high pressure so the artery walls are strong and elastic
walls are thick compared to size of lumen
contain thick layers of muscle to make them strong and elastic fibres to make them stretch and spring back
what do cappilaries do
are involved with the exchange of materials at the tissues
how are capillaries adapted to their function
carry the blood really close to every cell in the body so can exchange substances with them
permeable walls so substances can diffuse in and out
supply food and oxygen and take away waste (co2)
walls one cell thick - increases rate of diffusion
what do veins do
carry blood to heart
how are veins adapted to their function
blood is at low pressure so walls dont need to be as thick
bigger lumen than arteries to help blood flow
valves to keep blood flowing in right direction
if an animal has a small surface area to volume ratio what does this mean
their volume is large compared to their surface area
why is the left ventricular wall thicker than the right ventricular wall
has to pump blood further around the body compared to the right side
what side of the heart pumps deoxygenated blood to the lungs
the right side of the heart
whats the functions of valves in the heart
valves stop the blood from flowing backwards
how is cardiac muscle adapted to its function
cardiac muscle contains lots of mitochondria to provide the cells with ATP so the cardiac muscle can contract
what does blood consist of
plasma, platlets, red blood cells, white blood cells
what do red blood cells do
transport oxygen from the lungs to all the cells in the body
what is plasma
liquid that carries everything in blood
what are 2 waste products carried away in plasma
carbon dioxide ( carried from body cells to the lungs to be breathed out)
urea ( carried from liver to the kidneys where its removed in urine)
how is plasma adapted to its function
Plasma is clear and watery. This makes it suitable to transport molecules as many of them are soluble in water.
what is the function of red blood cells
to transport oxygen from the lungs to all the cells in the body
how are red blood cells adapted to their function
small and biconcave disc shape to give large surface area to volume ratio for absorbing + releasing oxygen
dont have a nucleus - frees up space for more haemoglobin so they can carry more oxygen
small and flexible so can pass through capillaries
whats the importance of haemoglobin in red blood cells
enables red blood cells to carry oxygen around the body
in the lungs, haemoglobin binds to oxygen to become oxyhaemoglobin
in body tissues oxyhaemoglobin splits up to release oxygen to the cells
what are the minerals that plants take up and why
magnesium for making chlorophyll
phospherous to make dna and cell membranes
what do phloem tubes do
transport food both up and down the stem to storage tissues.
what do xylem tubes do
carry water and minerals from the roots up the shoot to the leaves in the transpiration stream
whats translocation
the movement of sugar to all other parts of the plant
whats transpiration
the loss of water from the plant through the evaporation and diffusion of water from a plants surface
whats the transpiration stream
the movement of water through the xylem tissue
why is the transpiration stream constant in a plant
evaporation and diffusion of water from the leaves create a shortage of water in the leaves
means more water is drawn up from the rest of the plant through the xylem vessels to replace it
causes more water to be drawn up through the roots
whats the 4 benefits of the transpiration stream in a plant
constant stream of water from ground helps keep plant cool
provides plant with constant supply of water for photosynthesis
water creates turgor pressure in the plant cells to help support the plant and stop it wilting
minerals needed by the plant can be bought in from soil along with the water
how are phloem adapted to their function
cells are arranged end to end to form phloem tubes with sieve plates inbetween them to allow movement of substances through the plant
how are xylem adapted to their function
thick side walls strengthened by lignin which allows plant to withstand pressure of water moving through the plant
whats a transpiration stream
the flow of water through a plant, from the roots to the leaves, via the xylem vessels.
whats a stomata
Stomata are tiny holes found in the underside of leaves. They control water loss and gas exchange by opening and closing
whats the 3 things transpiration rate affected by
increase in light intensity
increase in temperature
increase in air movement
how is the transpiration rate affected by an increase in light intensity
brighter the light, greater the transpiration rate
increases the rate of photosynthesis causing stomata to open and let c02 in
stomata close when dark as photosynthesis cant happen in the dark
when stomata are closed water cant escape
how is the transpiration rate affected by an increase in tenperature
the warmer it gets , faster transpiration happens
when warm, water particles have more energy to evaporate an diffuse out of stomata
how is the transpiration rate affected by an increase in air movement
lots if air movement (wind) around leaf transpiration happens faster
if air around leaf is still water vapour surrounds leaf and dosnt move away
means high concentration of water particles outside of leaf as well as inside it so diffusion dosnt happen as quickly
if windy, water vapour is swept away maintaining low concentration of water in the air outside leaf
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