Science - Biology - Organisation - Tissues, Organs, and Organ Systems -B2a Flashcards
what are cells ?
the basic building blocks of life that make up living organisms
what is differentiation
the process by which cells become specialized for a particular job
arrange these in order :
organs
tissues
cells
organ systems
cells
tissues
organs
organ system
what is a tissue ?
a group of similar cells that work together to carry out a particular function
give an example of a tissue in mammals and it’s function
muscular tissue - contracts to move whatever it’s attached to
what is the function of the glandular tissue ?
makes and secretes substances like enzymes and hormones
what is the function of the epithelial tissue ?
covers some parts of the body e.g the gut
what is an organ ?
a group of different tissues that work together to perform a certain function
what tissues is the stomach made out of ?
muscular tissue
glandular tissue
epithelial tissue
what is an organ system ?
a group of organs working together to perform a particular function
what is the digestive system ?
an organ system that breaks food down
what organs is the digestive systems made up of ?
glands - pancreas and salivary
stomach
liver
small intestine
large intestine
what happens in the lungs ?
gas exchange - oxygen and carbon dioxide
where are the lungs ?
in the thorax
what protects the lungs ?
the rib cage
explain airs journey to the lungs
air you breathe goes through the trachea
splits into tubes called bronchi
the bronchi splits into smaller tubes called bronchioles
the bronchioles end at small bags called alveoli where gas exchange happens
what is the alveoli ?
millions of little air sacs where gas exchange happens
why does oxygen and carbon dioxide diffuse in and out of the alveolus ?
oxygen diffuses out of the alveolus and into the blood and carbon dioxide diffusers into the alveolus and out of the blood
when blood reaches body cells what does oxygen do ?
oxygen is released from the red blood cells and into body cells
what happens to carbon dioxide in the body cells ?
it diffuses out of the body cells into the blood and then is carried back to the lungs
what is the calculation for breathing rate ?
number of breaths /
number of minutes
amy takes 108 breaths in 9 minutes. what is her average breathing rate per minute ?
108/9 = 12 breaths per minute
what is the function of the circulatory system ?
to get food and oxygen to every cell in the body
explain the double circulatory system
- in the first circuit the right ventricle pumps deoxygenated blood to the lungs to take in oxygen, the blood then returns to the heart
- in the second circuit the left ventricle pumps oxygenated blood around all other organs of the body, the blood gives up its oxygen at the body cells and the deoxygenated blood returns to the heart to be pumped out to the lungs again
what is the heart ?
a pumping organ that keeps blood flowing around the body
what are the walls of the heart made up of ?
muscle tissue, which contracts to pump blood
what are the 4 chambers of the heart ?
left atrium
right atrium
left ventricle
right ventricle
what are the main vessels leading out of the chambers ?
vena cava
pulmonary artery
pulmonary vein
aorta
what is the function of valves ?
to make sure the blood goes in the right direction, prevents it flowing backwards
what do the coronary arteries do ?
branch of the aorta and surround the heart to make sure it gets all of the oxygenated blood it needs
explain the blood flow cycle of the heart
-blood flows from vena cava and pulmonary vein into the 2 atria
-the atria contract, pushing the blood into the ventricles
-the ventricles contract, forcing the blood into the pulmonary artery and the aorta out of the heart
-the blood then flows to the organs through the arteries and returns through veins
-the atria fill again and cycle repeats
what does an artificial pacemaker do ?
controls a heartbeat, if the natural pacemaker cells don’t work properly, it produces an electric current to keep the heart beating regularly
what do arteries do ?
carry blood away from the heart, towards the organs
describe artery walls
strong, elastic, thick
what are capillaries ?
they are involved in the exchange of materials at tissues and supply food and oxygen to the cells and take away waste products like carbon dioxide
how are capillaries adapted to help it’s function ?
permeable walls so exchanged substances can easily diffuse in and out
narrow, giving them a large surface area compared to volume ratio giving them an increased rate of diffusion
what do veins do ?
carry blood to the heart
how are veins adapted to help it function ?
thick lumen to help blood flow
how do you calculate blood flow ?
volume of blood /
number of minutes
800 ml of blood passed through an artery in 2 minutes.
calculate blood flow
800/2 = 400 ml/min
what is blood ?
a tissue that transports substances around the body
what is blood made up of ?
red blood cells
white blood cells
platelets
- all of which are suspended in plasma
what do red blood cells do ?
transport oxygen around the body
how are red blood cells adapted to its function ?
bioncave shape to give a large surface area
contain red pigment called haemoglobin to carry more oxygen
no nucleus so more room for oxygen
what do white blood cells do ?
defend against microorganisms that cause disease
how do white blood cells carry out their jobs ?
-engulf unwelcome microorganisms in a process called phagocytosis to digest them
- produce antibodies to fight microorganisms
- produce antitoxins to neutralize any toxins produced by microorganisms
what do platelets do ?
help blood clot at a wound which stops you losing to much blood and stop’s microorganisms getting in at the wound
what can a lack of platelets lead to ?
lots of bleeding and bruising
what does plasma do ?
carry everything in the blood, e.g
red blood cells
nutrients
proteins etc
what type of tissues are plant organs made of ?
- epidermal tissue
- palisade mesophyll
- spongy mesophyll
- xylem and phloem
- meristem tissue
where is the epidermal tissue ?
on the entire plant
what happens at the palisade mesophyll tissue ?
most of photosynthesis
what is the spongy mesophyll ?
contains big air spaces to allow gases to diffuse in and out of cells
what does the xylem and phloem do ?
transport things like water, mineral ions, and food around the plant
what is the meristem tissue ?
found at the growing tips of shoots and roots and is able to differentiate into lots of different types of plant cells
where is the meristem tissue found ?
growing tips of shoots and roots
what are epidermal tissues covered in ?
waxy cuticle
what does the waxy cuticle do ?
reduce water loss by evaporation
how is the upper epidermis suitable for its job ?
it is transparent so light can pass through it to the palisade layer
what does the palisade layer contain ?
lots of chloroplasts
why does the palisade layer contain lots of chloroplasts ?
so as much photosynthesis can happen as possible - gets the most light
what do the xylem and phloem form ?
a network of vascular bundles
what do the vascular bundles of xylem and phloem cells do ?
- deliver water and other nutrients to the entire leaf
- take away the glucose produced by photosynthesis
- support the structure
how are the tissues of the leaves adapted to suit its function ?
- suited for good gas exchange
- lower epidermis is full of little holes
what are stomata ?
holes in the lower epidermis which lets CO2 diffuse directly into the leaf
what controls the opening and closing of the stomata ?
guard cells
how do the guard cells know when to open and close the stomata ?
they respond to environmental conditions
what helps to increase the rate of diffusion of gases in the leafs structure ?
air spaces in the spongy mesophyll
what are phloem tubes made up of ?
columns of elongated living cells with small pores in the end walls to allow cell sap to flow through
what is cell sap ?
a liquid that’s made up of the substances being transported and water
what do phloem tubes do ?
transports food substances made in the leaves to the rest of the plant for immediate use or for storage
what direction does the transport for phloem tubes go in ?
both directions -
from the leaves down to the roots
from the roots to the leaves
what is translocation ?
the movement of dissolved sugars around the plant
what are xylem tubes made of ?
dead cells joined end to end with no end walls between them and a hole down the middle
how are xylem tubes strengthened ?
by a material called lignin
what do xylem tubes do ?
carry water and mineral ions up the plant form the roots to the leaves
what is the transpiration stream ?
movement of water from the roots through the xylem and out of the leaves
what is transpiration ?
the loss of water from a plant
describe the transpiration stream ?
1 - water from inside a leaf evaporates and diffuses out of the leaf, mainly through the stomata
2- this creates a slight shortage of water in the leaf so more water is drawn up from the rest of the plant through the xylem vessels to replace it
3- this in turn means more water is drawn up from the roots so then there’s a constant transpiration stream of water through the plant
what is transpiration a side-effect of ?
photosynthesis
what does water escape the leaves through ?
the stomata through diffusion
what are the 4 things affected by transpiration rate ?
- light intensity
- temperature
- air flow
- humidity
how is transpiration affected by light intensity ?
brighter the light = greater the transpiration rate because the stomata begins to close as it gets darker when the stomata is closed water can’t escape
how is the stomata used in transpiration ?
the stomata which is also used for gas exchange helps to get rid of water from transpiration through diffusion
how does temperature affect transpiration ?
the warmer it is the faster transpiration happens because when it is warm particles have more energy to evaporate and diffuse out of the stomata
how does air flow affect transpiration ?
- the better air flow, the greater the greater the transpiration rate
- if there is good air flow water vapour is swept away maintaining a low concentration of water in the air outside the leaf as diffusion happens quickly from an area of high to low concentration
how does humidity affect transpiration ?
- the drier the air around the leaf the faster transpiration happens
- diffusion happens fastest if there is a really high concentration in one place and a really low concentration in the other
how do you investigate transpiration rate ?
- measure the uptake of water by a plant
why can you investigate transpiration rate ?
you can assume that water uptake by the plant is directly related to water loss by the leaves
describe how to investigate transpiration rate ?
record the starting position of the air bubble
start a stopwatch
record the distance moved by the bubble per unit of time
what do you need to keep the same when investigating the rate of transpiration ?
keep conditions constant throughout
what happens to the guard cells when the plant has lots of water ?
guard cells fill with water and go plump and turgid
what happens when the guard cells go plump and turgid ?
the stomata opens up so gases can be exchanged for photosynthesis
what happens to the guard cells when the plant is short of water ?
- guard cells lose water and become flaccid
what happens when the guard cells go flaccid ?
the stomata will close to stop water vapour from escaping
how are the outer and inner walls of the guard cells adapted to their function ?
- they are sensitive to light and close at night to save water
why are stomata on the underside of the leaf ?
so they are in a more shaded and cooled area so less water is lost through the stomata
describe how to investigate stomata and guard cells ?
- peel the epidermis straight of the leaf and mount onto a microscope slide with a cover slip
- as you can’t peel the top layer of the surface of use a clear nail varnish and dry it, use a piece of sticky tape to remove the varnish of the leaf by gently peeling it off and stick with sticky tape onto a microscope slide
- view the slide under the microscope
- estimate the total number of stomata with a sample - using what you can see in your field of vision and repeat 3 times
- estimate how many times the field of vision would fit into the stomata by finding the area of the field and dividing by the total area of the surface
- multiply your answer by the average number of stomata per field of vision
do this in different areas of the leaf to compare how different parts of the leaf has different distribution of stomata
what do you need when investigating the distribution of stomata ?
a light microscope
what is health ?
the state of physical and mental wellbeing
what is a communicable disease ?
diseases which can be spread from person to person or between animals and people
what are the 2 types of diseases ?
communicable
non-communicable
what are non-communicable diseases ?
diseases which cannot spread
how long do non- communicable diseases last ?
a long time
what is a communicable disease also known as ?
infectious or contagious diseases
what affects health ?
- diet
- stress
- life situation
what is cardiovascular disease ?
a term used to describe diseases of the heart or blood vessels
give an example of a cardiovascular disease ?
coronary heart disease
what is coronary heart disease ?
when the arteries that supply blood to the heart muscle is blocked by layers of fatty material building up, causing arteries to become narrow
what are the affects of coronary heart disease ?
blood flow is restricted and there’s a lack of oxygen to the heart muscle which can cause a heart attack
what is a stent ?
wire mesh tubes
what are stents used for ?
they are inserted inside arteries to widen them and keep them open
what diseases are stents used for ?
coronary heart disease
how do stents help with coronary heart disease ?
they keep coronary arteries open, making sure blood can pass through to the heart muscles, keeping the persons heart beating
what are the advantages of stents ?
- they lower the risk of heart attack
- effective for a long time
- recovery time from surgery is quick
what are the disadvantages of stents ?
risk of infections during surgery
risk of blood clot
what is thormbosis ?
the risk of a blood clot from stents
what are statins ?
drugs that reduce the amount of ‘bad’ cholesterol present in the bloodstream
what is cholesterol ?
an essential lipid that your body produces to function properly
what is bad cholesterol known as ?
LDL cholesterol
what can LDL cholesterol cause ?
fatty deposits to form inside arteries
what do statins help stop ?
fatty deposits inside arteries forming
what are the advantages of statins ?
- can reduce the risk of strokes, coronary heart disease, heart attacks
- increases the amount of good- HDL cholesterol in your bloodstream
- removing LDL cholesterol can remove other diseases
what is good cholesterol called ?
HDL cholesterol
what is the disadvantage of statins ?
- they need to be taken regularly
- headaches
- kidney failure
- memory loss
- they don’t kick in instantly
if someone needs a heart transplant but donor organs aren’t available what can be done ?
artificial hearts may be used
what are artificial hearts ?
mechanical devices that pump blood for a person who’s own heart has failed
are artificial hearts usually temporary or permanent ?
temporary
what are the advantages of artificial hearts?
- less likely to be rejected by the body’s immune system than a donor heart
why are artificial hearts less likely to be rejected than a donor heart ?
they are made from metals or plastics so the body doesn’t recognise them as foreign
what are the disadvantages of artificial hearts ?
- surgery can lead to bleeding and infection
- don’t work as well as healthy ones
- parts of the heart could wear out and fail
- blood doesn’t flow as smoothly which can cause blood clots
- when recieving an artificial heart patient has to take drugs to thin their blood so clots don’t occurr - this can lead to issues if injured as blood can’t help clot to heal wounds
- uncomfortable
why can valves stop working ?
damaged by heart attacks
old age
what can damage to valves cause ?
valve tissue to stiffen so it doesn’t open properly, or a valve may be leaky
what can a leaky valve cause ?
blood to flow both ways
how can valves be replaced ?
biological valves
mechanical valves
what are biological valves ?
valves taken from mammals
what are mechanical valves ?
man-made valves
what are the disadvantages of valve replacements ?
blood clots can happen
what is artificial blood ?
a blood substitute e.g a salt solution (saline) which is used to replace a lost volume of blood
what are risk factors ?
things that are linked to an increase in the liklelihood that a person will develop a certain disease during their lifetime
what can risk factors be ?
- aspects of a persons life
- substances in the environment
where are the risks of non-communicable diseases higher and why ?
in deprived areas because people are more likely to smoke, not exercise and have a good diet
in higher income diseases because they eat more processed food
give examples of risk factors which cause disease ?
- smoking
- obesity
- drinking alcohol
- smoking when pregnant
what are human costs of non-communicable diseases ?
- millions of people die
- people have lower qualities of life
- shorter lifespans
what are the financial costs of non-communicable diseases ?
- cost of researching and treating the disease is huge
- families may have to move homes or adapt their life which can be costly
- if people are ill they can’t work = can effect economy if many people are ill
what is cancer caused by ?
uncontrolled cell growth and division which occurs change to the cells and causes a tumour
what is a tumour ?
a growth of abnormal cells
what are the 2 types of tumours ?
benign
malignant
what are benign tumours ?
where tumours grow until there’s no room - the tumour stays in 1 place rather than invading other tissues in the body
are benign tumours dangerous ?
no
what are malignant tumours ?
where a tumour grows and spreads to neighboring healthy tissues - it can cause cells to break off and spread to other parts of the body travelling in the bloodstream
what do malignant tumours form ?
secondary tumours
are malignant tumours dangerous ?
yes - they are cancers
give risks of cancer ?
- smoking
- obesity
- UV exposure
- viral infection
what are genetic risk factors of cancer ?
genes you inherit from your parents can be faulty increasing risks to cancer
mutations in BRCA genes increase chances of breast and ovarian cancer
what are enzymes ?
biological catalysts and speed up useful chemical reactions in the body
why do reactions in the body need to be carefully controlled ?
to get the right amounts of substances
how can you make a reaction happen more quickly ?
by increasing the temperature
why is increasing the temperature not good to speed up a reaction inside the body ?
it can speed up unwanted reactions which can damage cells
what is catalyst ?
a substance which increases the speed of a reaction without being changed or used up in the reaction
what are enzymes made up of ?
large proteins
made up of chains of amino acids
why are enzymes amino acid chains all different shapes ?
as they all have different jobs
what does every enzyme have ?
an active site
what is an active site ?
a unique shape that fits onto the substance involved in the reaction
why do enzymes only catalyse for 1 specific reaction ?
the substrate has to fit into its unique active site
what is the locke and key theory ?
each enzyme has a uniquely shaped active site where only 1 substrate can fit into it to form the products, like a lock and key
what is an induced fit ?
where the active site changes slightly as the substrate binds to it to get a tighter fit
what is an optimum condition ?
the best conditions
how can temperature effect enzyme action ?
the higher the temperature, the faster the rate at first
if it gets too hot the bonds holding the enzyme together will break which changes the shape of the enzymes active site so the substrate won’t fit into it anymore = denatured
what does denatured mean ?
the temperature has got too hot the the substrate will no longer fit into the enzymes active site
what is the optimum temperature for enzyme action in the human body?
37 degrees
how does PH affect enzyme action ?
it it is too high or low, the PH interferes with the bonds holding the enzyme together which can change the shape of the active site and denatures the enzyme
what is the optimum PH for lots of enzymes and why ?
PH 7 -because its neutral
what does the enzyme amylase do ?
breakdown starch into maltose
how do you detect starch ?
using iodine if starch is present, solution will turn from orangey-brown to blue-black
describe how PH effects amylase activityexperiment ?
- put a drop of iodine solution on a spotting tile
- place a bunsen burner and heat water over it until is reaches 35 degrees
- use a syringe to add 1cm cubed of amylase solution and 1cm of a buffer solution with a PH 5 to a boiling tube, using test tube holders, put the boiling tube into a beaker of water and wait 5 minutes
- use a different syringe to add 5cm cubed of starch solution to the boiling tube
- mix the contents of the boiling tube and start a stopwatch
- use continuous sampling to record how long it takes for amylase to break down all the starch by using a dropping pipette to take a fresh sample from the boiling tube every 30 seconds and put into a well
- when iodine remains brown, starch is no longer present
- repeat with buffer solutions of different pH to see how pH affects the time taken for starch to be broken down
how do you calculate rate of reaction when investigating pH on amylase ?
1000/time
what are the units for rate of reaction when investigating pH on amylase ?
s-1
what is the digestive system ?
an organ system that breaks down food so nutrients can be absorbed into your body from the gut
how is food broken down ?
mechanical digestion
chemical digestion
what is mechanical digestion ?
teeth grinding food down
what is chemical digestion ?
enzymes help to break down food
how are enzymes involved in digestion produced ?
by specialised cells in glands and in the gut lining and then released into the gut to mix with food molecules
what happens to starch, proteins and lipids when they want to pass through the digestive system ?
digestive enzymes break these big molecules down into smaller ones which are soluble and can pass easily through the walls of the digestive system allowing them to be absorbed into the bloodstream
what can the products of digestion be used to make ?
new carbohydrates, proteins and lipids
what do the carbohydrase enzymes break down ?
carbohydrates into simple sugars
give an example of a carbohydydrase ?
amylase - it breaks down starch
where is amylase ?
salivary glands
pancreas
small intestine
what are protease enzymes ?
digestive enzymes that catalyse the convertion of proteins into amino acids
where are proteases made ?
stomach
pancreas
snall intestine
where does amylase work ?
mouth
small intestine
where do proteases work ?
stomach
small intestine
what are lipase enzymes ?
digestive enzymes that catalyse the conversion of lipids into glycerol and fatty acids
where are lipases made ?
pancreas
small intestine
where do lipases work ?
small intestine
where is bile produced ?
in the liver
where is bile stored ?
the gall bladder before it is released into the small intestine
what does bile do ?
neutralises and makes the conditions alkaline in the small intestine because the hydrochloric acid in the stomach` makes it too acidic for enzymes in the small intestine to work properly
what does bile do to fats ?
breaks them into tiny droplets which gives a much bigger surface area for lipase to work on - makes digestion quicker
how do you prepare a food sample ?
1- break up food using a pestle and mortar
2- transfer the ground up food to a beaker and add distilled water
3- stir the mixture with a glass rod to dissolve the food
4- filter the solution using a funnel lined with filter paper which will get rid of the solid bits of food
what are the 2 types of sugars ?
non-reducing
reducing
how do you test for reducing sugars ?
using Benedicts test
how do you carry out Benedicts test ?
- prepare food sample and transfer 5cm3 to a test tube
- prepare water bath at 75 c
- add benedicts solution to the test tube
- place the test tube in the water bath and leave for 5 minutes
- if the food sample contains a reducing sugar the solution will change from blue to green , yellow or brick red
what does the colour the sugar solution will turn depend on ?
how sugary it is - the more sugar - the more red
how do you test for starch ?
1 - make a food sample and transfer 5cm3 to a test tube
2- add drops of iodine solution and shake the tube
3- if sample contains starch - colour of solution changes from orangey brown to blue black
what solution do you use to test for starch ?
iodine
how can you test for protein ?
- prepare a sample and transfer 2cm3 to a test tube
- add 2cm3 of Biuret solution to the sample and mix the contents of the food by shaking it
- if the food sample contains protein solution will change from blue to purple
what solution do you use to test for protein ?
biuret solution
how do you test for lipids ?
1- prepare food sample but do not filter, add 5cm3 to a test tube
2- use a pipette to add 3 drops of Sudan III stain solution to test tube and shake
3- if the food sample has lipids the mixture will separate into 2 layers
- the top layer will be bright red
- if no lipids form no separate layer will form at the top of the liquid
what tests for lipids and how ?
Sudan III stain
it stains lipids
