ORGANISATION Flashcards
cells are…
a tissue is…
organs are….
organs are organised into …. which work together to …..
the basic building blocks of all living organisms
-a group of cells w/ similar structure + function
-aggregations/group of tissues(that work together) performing specific functions
-organ systems- form organisms
what do
glandular tissue
epithelial tissue
do
glandular tissue- makes + secretes chemicals(makes digestive juices)
epithelial tissue- covers some parts of body (outside + inside of stomach)
in the digestive system , what do these organs do-
glands
stomach
small intestine
liver
large intestine
glands-produce digestive juices
stomach -digest food
small intestine-digest food and absorbs soluble food molecules
liver-produce bile
large intestine-absorbs water from undigested food
what does muscular tissue do- how x2
-muscular tissue moves stomach walls to churn food
muscular tissue-has muscle cells which contract for movement
the muscles cells have protein fibres which change length(to allow contractions)
-muscle cells have many mitochondria- provide energy for contraction
()
an organ is a group of tissues working together- give an example
stomach- contains muscular tissue and glandular tissue
3 main nutrients in food
-why do they have to be digested
-what happens during digestion
carbs(eg starch)-protiens-lipids(fats)
-large molecules- too large to be absorbed into blood stream
-digestive enzymes break large molecules into smaller ones so they can pass through the walls of digestive system and be absorbed into bloodstream
mouth,
oesophagus,
stomach,
small intestine,
large intestine
rectum.
-liver
-pancreas
-gall bladder
1)mouth-amylase enzymes in saliva digest starch into smaller sugar molecules
2)oesophagus-food passes down to
3) stomach- enzymes begin digesting protiens
-hydrochloric acid helps enzymes
-muscular walls churns food to fluid
4) sm. intestine-
chemicals released from liver(bile) and pancreas (enzymes)
-digestion continued
-walls of sm. i release enzymes
-small food molecules absorbed into bloodstream
5)large intestine-
water absorbed into blood stream
what happens in the mouth
what happens in the oesophagus
amylase enzyme in saliva digest starch into smaller sugar molecules
food passes down to stomach
what happens in stomach
1- why
2
3- and why x2
1-muscular walls churn food into fluid - increases s.a for enzymes to digest
2-produces protease enzyme pepsin-begins digesting proteins
3-produces hydrochloric acid to -
-kill bacteria
-give right acidic ph for protease enzyme to work
what happens in sm. intestine
1
2
3
4
1)where most of the digestion happens
2)digested food absorbed into bloodstream(diffuse/activetransport)
3) protease, amalyse,lipase enzymes from pancreas in form of pancreatic juices complete digestion
(also creates some itself)
4)gets bile from gall bladder
what does bile do x3
where is bile made
where is bile stored
-neutralises acid from stomach,
-makes ph more ideal for digestive enzymes
-emulsifies fats into smaller droplets-for greater s.a for enzymes to work on
-made-liver
-stored-gall bladder
what happens once food is digested in small intestine
-how is the lining of the small intestine adapted
x3
absorbed into blood stream
-has loads of villi which increase s.a of small intestine so diffusion of digested food into the blood stream is quicker
-villi have single layer of surface cells- short diffusion pathway
-villi- good blood supply-maintains concentration gradient
-what is the material left in the sm. intestine like-why
-what happens to this material that wasn’t absorbed into blood
x3
-because of secreation from pancreas,stomach,bladder, leftover material is watery
1)material passes to large intestine-
2)excess water absorbed by large intestine- faeces left behind
3)faeces left in rectum
9 steps to the digestive system
-food chewed-salivary glands add saliva
-down oesophagus and into stomach
-fluid pushed into small intestine
-mixes w/ pancreatic juices+ bile
-broken down and digested
-small molecules absorbed from sm. intestine into blood stream
-molecules that X be absorbed go to large intestine
-water from leftover material absorbed back into body
-faeces left behind in rectum
enzymes are—-
what type of molecules are enzymes-
describe lock and key theory-3 points
biological catalysts that speed up(catalyse) chemical reactions without being changed or used up
large protien molecules- all protiens made of chains of amino acids
-The shape of the substrate is complementary/specific to the shape of the active site
-when they bond it forms an enzyme-substrate complex.
-Once bound- reaction takes place, products released
from surface of the enzyme
what can enzymes do-not about catalysing
break up large molecules or join small ones.
what do digestive enzymes do
what are the products of digestion used for
convert food into small soluble molecules that can be absorbed into bloodstream
- build new carbs, lipids/protiens- some glucose used in respiration
what are the 3 digestive enzymes, what do they break down
what do they break them into
amylase(carbohydrase)- breaks starch(carb) into glucose(simple sugars eg maltose)
Proteases break down proteins into amino acids
Lipases break down lipids/fats into fatty acids + glycerol
protease enzymes made in
-what are protiens
-what does protease enzymes do -why(dont talk about digestion)
stomach
pancreas
small intestine
long chains of amino acids
-break protiens back into amino acids which are absorbed by body cells and joined in different order to make human proteins
amalyse made in
amalyse is a ….
-what is starch made of
salivary glands, pancreas, small intestine
carbohydrase
-chain of glucose molecules(it is a type of carb)
lipase is made in….
what is a lipid molecule made of-
pancreas and small intestine
-glycerol molecule + 3 fatty acid molecules
bile is made in …… and stored in …… It is ….. to neutralise ……. ……. from the stomach. It also ……. fat to form …… ……. which increases the ……. ……… The ……. conditions and large ……. ….. increase rate of fat breakdown by ……..
made in liver
stored in gall bladder
Its alkaline
neutralise hydrochloric acid in stomach
It emulsifies fat
to form small droplets
Increases S.A
The alkaline conditions & large S.A
increase rate of fat breakdown by lipase
4 food tests-what is added, what is a +ve test
Starchy Dina
Sweet Benedict
Protien Biuret
Fatty Sudan
-Starchy Dina- add iodine solution- —-> bluey/black
-Sweet Benedict-add benedict solution.
—> brick red
-Protien Biuret- add biurets
—-> purple
-Fatty Sudan-add Sudan III stain
—->separates to 2 layer- top one red
how do u prepare a food sample
-break up food w/ mortar + pestle
-put in beaker- add distilled water
-stir w/ glass rod
-filter -funnel lined w/ filter paper
-use the watery solution
what does the benedict test for
-steps to the test x4
-a positive test would be…
-safety precautions x2
-reducing sugars
1)add 5cm3 sample to test tube
2)prep water bath @ 75*c
3)add 10 drops benedict to tube
4)put tube in bath- 5 mins
- blue —> green/yellow/brick red- depend on sugar conc.
*use test tube holder
*point tube away from u
iodine test for starch
-steps to the test x 3
-a positive test would be
1) 5cm3 sample to tube
2) few drops iodine solution- will turn browny orange
3)gently shake
-browny orange —–> bluey black
biuret test for protiens
-steps to the test x 3
-a positive test would be
1) 2cm3 sample + 2cm3 biuret solution to tube
2)will turn blue
3)gently shake
-blue—-> pink/purple
Sudan lll test for lipids
-steps to the test x 3
-a positive test would be
1) 5cm3 sample (maybe unfiltered)
2) + 3 drops Sudan lll stain solution
3) gently shake
-mixture separate to 2 layers- top layer bright red
-what happens to reaction if temp increases
why
what does -‘optimum temp’ mean
what is optimum temp of most human enzymes
what happens if temp increased above optimum-why
-as temp increases, rate increases
-particles have more kinetic energy
-more collisions per second btwn substrate + active site
-once optimum temp exceeded- rate decreases
optimum- temp where enzyme working at fastest rate- maximum frequency of successful collisions btwn substrate and active site
-37*c
-activity of enzyme rapidly decreases.
-too hot- bonds holding enzyme break- shape of active site changes-
-enzyme denatured
-enzyme can’t catalyse reaction
-what happens to reaction if ph made more acidic/ alkali then the optimum- why
what does -‘optimum ph’ mean
generally, optimum enzyme ph is-
-Enzymes released from pancreas into sm. intestine work best at ….
-Enzymes in stomach work best at…
enzyme activity drops to 0
-active site denatures if conditions too acidic/alkaline
-ph when enzyme works at fastest rate-rate of reaction highest
-7-neutral- (enzymes have specific optimum ph’s)
-alkaline ph
-acidic ph
is the damage done to an enzyme when it denatures permanent or reversible
The presence of starch is a sign that…
-how
permanent
.
.
that photosynthesis has occured
-product of photosynthesis is glucose
-plants store glucose as starch
RP effect of Ph on amylase
Step 1
Place drop of iodine solution into each well of spotting tile
Step 2
Take 3 test tubes - label each one
Step 3
1st test tube = add 2cm cubed of starch solution
2nd test tube = add 2cm cubed of amylase solution
3rd test tube = add 2cm cubed of PH5 buffer solution
Step 4
Place all 3 test tubes in water bath at 30 degrees-leave for 10 mins so they reach right temp
Step 5
Combine 3 solutions into one test tube + Mix w/ stirring rod
Step 7
Return test tubes to water bath- start stop watch
Step 8
After 30 seconds use the dropping pipette to transfer one drop of solution to a well in the spotting tile that contains iodine
what does buffer solution do
what will happen in the spotting tiles-
-how long do we continue to add solution to the tiles.
-why do we stop
-what do we do once iodine doesn’t change to bluey black
Buffer solution - used to control PH
The iodine turn blue-black as starch is present
-Take a sample every 30 seconds and continue until iodine remains orange
When iodine remains orange - tells us that starch is no longer present and the reaction has been completed
stop timer-
We record the time for this in our results
Repeat whole experiment several times using different PH Buffers
eg PH 6, PH 7, PH 8
Rp effect of Ph on enzyme activity
-what are the problems with the experiment-how would you address it x4
What are the control variables
-only taking samples every 30 secs, only have approximate time.
-take sample every 10 secs
-not always obvious when iodine doesn’t go bluey black- hard to see when reaction complete -
-ask few ppl to look at tile + decide when reaction complete
-use a ph meter to measure ph more accurately
-could use an electric heater to control temp - more accurate than a normal water bath
-concentration/ volume of amylase solution
how to calculate rate of reaction x2
what’s the 2 units for rate
1000/time
s to power -1
OR
amount of product formed/time
cm 3 / s to power -1
how is the small intestine adapted to absorbing products of digestion
x5
-very long-large s.a for absorbtion of products of digestion
-interior covered in villi- increase s.a
-villi have microvilli- further increase s.a
-villi have good blood supply-blood stream rapidly removes products of digestion- increases conc. gradient
-villi have thin membrane- short diffusion path
describe track of air through the different organs and parts of your chest- 5 points
(thorax is the top part of the bod, separated from lower bod by diaphragm) (Lungs protected by ribcage + surrounded by pleural membranes)
-Air goes through trachea
-trachea splits into 2 bronchi
-each bronchi goes to each lung
-bronchi then split in to bronchioles
-bronchioles end in sacs called alveoli
-feature of trachea
-what happens at alveoli
rings of cartilage stop trachea collapsing when inhaling
- gases diffuse in and out of blood- sites of gas exchange
how does breathing affect rate of gas diffusion in alveoli
increases rate- brings fresh O2 into alveoli, takes away carbon- dioxide- makes concentration gradient high
process of alveoli in gas exchange- 3 steps
-blood passing through capillaries, next to alveoli contains lots of CO2- little O2 - has just returned from rest of body
-oxygen diffuses out alveolus into blood.
-Carbon dioxide diffuses out blood to alveolus to be breathed out
-process of gas exchange btwn blood and body cells - 3 steps
-oxygenated blood reaches cells,o2 diffuses into cells
-CO2 diffuses out cells into blood and carried back to lungs
-then diffuses into alveoli to be breathed out
how can you calculate breathing rate per min
-bob takes 91 breaths in 7 mins- calculate average rate in breaths per minute
no. of breath/ no. of minutes
91/7 = 13
13 breaths per minute.
describe the single circulatory system in fish
-4 points
-deoxygenated blood pumped from heart to gills
-collects oxygen
-oxygenated blood passes straight to organs
-O2 diffuses into body cells
-blood returns to heart
what is a problem w/ single circulatory system in fish
blood loses alot pressure as it passes to gills bfore organs- so passes to organs slowly- so can’t deliver alot of oxygen
describe the double circulatory system in humans
6 points
3 for right ventricle
3 for left ventricle
-right ventricle pumps deoxygenated blood to lungs
- it takes in o2
- oxygenated blood returns to heart
-left ventricle pumps oxygenated blood around body.
-oxygen diffuses from blood into body cells.
-deoxygenated blood returns to heart to be pumped to lungs again
what are heart walls mainly made of-
what are the four chambers of the heart as though you were looking at a heart
-where are the valves- what do they do-
muscle tissue
right atrium ||||| left atrium
right ventricle ||||| left ventricle
-stop backflow of blood in the heart (when atria contract)- they separate the atria from ventricles
what are the 4 main blood vessels entering and leaving heart
-what side are they on
which side of heart deals w/ O2 blood
pulmonary artery-R-upper
vena cava- R-lower
aorta-L-upper
pulmonary vein-L-lower
-left side- the side that is on your right when u look at a pic- deals with oxygenated blood
what do these do:
vena cava
pulmonary artery
pulmonary vein
aorta
-vena cava- brings XO2 blood from body to heart
-pulmonary artery- carries XO2 blood from heart to lungs
-pulmonary vein- carries O2 blood from lungs to heart
-Aorta- pumps O2 blood from heart to body
describe the pattern of blood flow through the heart- 3 points
-blood enters right atrium from vena cava
and left atrium from pulmonary vein
-atria contract, blood forced into ventricles
-ventricles contract - blood forced out of heart
through pulmonary artery (to lungs)
through aorta (to body)
-which side has a thicker muscular wall
-why
left side- (side on your right if u look at pic)
bcse left ventricle pumps blood around body- so needs greater force
what are coronary arteries
what do they do-
how is this helpful
-arteries that branch out from aorta + spread into heart muscle
-provide oxygen to muscle cells of heart.
-the oxygen is used in respiration to provide energy for contraction
-how is natural resting heart rate controlled
-where is it
-what do they do
by group of cells that act as a pacemaker
-right atrium
(produce small electrical impulses that spread through the muscular walls of the heart, causing them to contract)
what are artificial pacemakers
electrical devices used to correct irregularities in heart rate
—-implanted under skin- has wire going to Heart-produces electric current to keep heart beating regularly—-
what do these blood vessels do-
Arteries
capillaries
veins do
carry high press blood Away from heart
-exchange nutrients + oxygen w/ tissues
- carry blood to heart
-why do arteries need to be strong and elastic
features of arteries
x3
because blood is pumped from heart at high pressure
-walls have thick muscular tissue- to withstand high pressure blood from heart
-walls contain elastic fibres- stretch when surge of blood passes through + recoil between surges- keeps blood moving
-therefore walls are thick compared to lumen
what do capillaries do-
features of capillaries x4
-blood passes through capillaries, glucose/food/o2 ect diffuse into cells and co2 out from cells to blood
(exchange substances w/ cell)
-permeable walls- substances can diffuse in/out
-very thin walls-increase rate of diffusion-shorter diffusion distance
-small lumen
-very tiny
what is the pressure of blood through capillaries like
lower blood pressure than arteries
(bcse there is a much higher cross section of capillaries than arteries)
what is the pressure through the capillaries like
less pressure than in arteries
(bcse though capillaries are small, there are so many they have a larger cross sectional area)
what is the pressure like in veins
why is this a risk
features of veins x3
-blood flows at low pressure , slowly to heart
-could stop or flow back
-thin wall-(low pressure blood so X need thick walls)
-contain valves to stop backflow
-bigger lumen than arteries
how do valves work
when blood flows in correct direction, valves open. when blood flows backwards, valves shut.
1464ml passed through artery in 4.5 mins- calculate rate of blood flow in ml/min
vol of blood/ minutes
1464/4.5 =325 ml/min
4 main things in blood
red blood cells- carry O2 from lungs to cells
white blood cells-defend against infection
plasma- liquid part of blood that transports dissolved substances around body
platelets-help blood clot
what does plasma transport x4 and from where to where
* 3 extras substances
Plasma make up 50%+ of bloods volume
what does plasma do-
-red, white blood cells,platelets
-soluble products of digestion-
(glucose/amino acids) from sm. intestine to organs
-co2- from organs to lungs
-urea- from liver to kidneys
*hormones
*protiens
*antibodies/ antitoxins(produced by wbc)
-makes blood watery so it can flow
what do red blood cells do-
-adaptations of rbc x3
transport o2 from lungs to cells
1)has oxygen carrying molecule haemaglobin-gives red pigment
2)has X nucleus- more room for haemaglobin + oxygen
3)biconcave disc shape=greater s.a = quicker diffusion of O2
what happens to the haemaglobin in rbc
in lungs,
in organs
In LUNGS - haemoglobin binds to oxygen = oxyhaemoglobin
-IN ORGANS oxyhaemaglobin splits= haemoglobin + oxygen
-oxygen released to cells
what do white blood cells do.
White blood cells have DNA- why is this important
Make up less than1% of blood
engulf pathogens in phagocytosis
produce antibodies and antitoxins
-dna encodes instruction the white blood cells need to do their job
what are platelets
-what subcellular structure do they not have
what happens if u have lack of platelets
tiny fragments of cells that help blood clot
-have no nucleus
-excessive bleeding/bruising
-microorganisms get into open wound
uses of donated blood in medicine x3
-replace blood lost during injury
-ppl given platelets extracted from blood to help w/ clotting
-protiens extracted are useful eg antibodies
problems w/ using blood transfusion- x2
-in blood transfusion- donated blood must be same blood type as patients- immune system will reject blood- patient could die
-diseases can be transmitted via blood
-in uk, blood screened for infections so low risk
what is artificial blood
pros x2
cons x2
-mostly salt water
-adds volume-keeps vessels full
-allows heart to carry pumping
- X contain any rbc- X transport any o2
-so we can only replace 1/3 of blood w/ it
what happens in coronary heart disease- 2 points
what are the effects- 3 points
-layers of fatty material build up inside the coronary arteries
- narrowing them
-reduces the flow of blood through the arteries
- causing lack of oxygen for heart muscle
-can lead to heart attack( heart is oxygen starved)
cardiovascular diseases are diseases of the…..
-are they communicable- explain
-heart and blood vessels
-non communicable- not infectious/passed from person to person
treatments for chd- briefly explain what they are
**stents- tubes inserted into artery to keep it open
**statins- drugs that reduce level of cholesterol in blood
-slow down rate fatty materials build up in arteries
STENTS-
pros x3
cons x4
- blood can flow normally through artery- lower risk of heart attack
-effective for a long time
-quick recovery time from surgery
-Doesn’t treat underlying cause- X stop other regions narrowing
-risk of complications during operation eg heart attack
-risk of infection in surgery
-could develop blood clot near stent-(thrombosis)
STATINS
what do they do-
pros x3
cons x3
-slow down rate fatty materials build up in arteries
-increase amount of beneficial cholestrol(hdl) - - in blood stream. which removes ‘bad’ cholestrol(ldl)
-effective- proven to reduce risk of chd by reducing bad cholestrol
-studies suggest they may help prevent other diseases-eg strokes, heart attacks
-have side effects-eg- (kidney failure, liver damage, memory loss)
-effects X instant- takes time for effects to take hold
-long term drug- taken regularly-could forget to take them
what is cholestrol
what are the two forms
when do the fatty deposits build up in the artery-
when are stents used instead of statins
a lipid
‘bad’ - LDL type
‘good’- HDL type
-too much bad type
-when a coronary artery is almost totally blocked
2 types of cardiovascular diseases
CHD
Faulty heart valves/leaky heart valves
heart attacks
heart failure
what happens in faulty heart valves
what happens in leaky valves
what causes leaky/faulty valves x3
symptoms/effects valve problems-
-valves don’t fully open - heart pumps extra hard to get blood through-heart enlarges
-leaky- blood flows in both directions - doesn’t circulate as effectively as normal
-heart attacks, infection, old ages
-feel weak/tired/dizzy/chest pain/rapid heart rate. (wont always have symptoms)
hoe can problems w/ valves be fixed
-con of both of these-
pro and con of each-
replace w/ biological / mechanical vales
-need surgery
mechanical -
-last lifetime
-increase risk of blood clot- must take anticlotting drugs
biological
-dont last as long
-dont need to take drugs
what is the treatment for heart failure
what is heart failure-
-donor heart/donor heart and lungs
-artificial hearts
when heart can no longer properly pump blood around body
problems w/ donor hearts x2
problem of both hearts-
why are artificial hearts usedx2
-not enough available
-must take drugs to stop immune system rejecting donor heart
-need surgery- can lead to bleeding + infection
-temporary solution to keep patient alive while waiting for heart transplant
-to help recovery by allowing damaged heart to rest/heal
problems w/ artificial hearts x4
pros of artificial hearts-
-increase risk of blood clotting-must take blood thinning drugs
-blood thinning drugs cause problems w/ bleeding if person is hurt
-not long term solution, only be used for short period
-don’t work as well-can wear out or electric motor can fail
-less likely to be rejected by immune system-made of metal/plastic- not identified ‘foreign’ and attacked the same way living tissue is.
is artificial blood safe-
pro of artificial blood-
- what would an ‘ideal’ blood product do-
-a pro of this-
yes, if no air bubbles get into blood.
-can keep patient alive if lost 2/3 of their blood- give time for new blood cells to be produced or get transfusion
-replace the function of red blood cells- no need for transfusion
-decrease risk of diseases passing on
what is health
What are major causes of ill health
what other factors affect mental and physical health
state of mental+physical wellbeing
-disease-communicable and non communicable
-diet
-stress
-life situations
examples of non communicable diseases- x3
what is a non communicable disease
cardiovascular diseases- type 2 diabetes- most types of cancer
-diseases that X caused by pathogen + cant be spread btwn ppl or btwn animals and ppl.
what are risk factors for cardiovascular diseases
what decreases chance-
-diet high in fat + low in veggies increases levels of ‘bad’ cholestrol in blood
-diet high in salt- increase blood pressure- increases risk
-smoking proven to directly cause it- damages walls of arteries
-regular exercise decreases risk
what is the effect of smoking on adults x3
-proven smoking directly causes lung cancer and lung disease-
increases risk of lung diseases (emphysema)
-damages the cells in lung lining
-the smoke contains carcinogens- chemicals which can trigger cancer
-what are the effects of smoking on unborn child- x3
-what are effects of drinking on unborn babyx2
-increases risk of miscarriage/premature birth
-afect development- maybe born w/ low body mass
-reduces amount of o2 baby recieves- causes it health problems-
-fetal alcohol syndrome-learning difficulties/mental,physical problems
-damage cells- affect development- may have low body mass
what is the effect of alcohol in adult
x6
-too much can cause LIVER DISEASE-
the reaction when liver breaks down alcohol can damage its cells
-liver CELLS DAMAGED when toxic chemicals leak from gut
due to damaged intestines due to alcohol
-brain function -damages NERVE CELLS in brain , causing brain to lose volume.
-increase risk of liver CIRRHOSIS and liver CANCER
-can lead to ADDICTION
-lead to MEMORY LOSS
risk factor of type 2 diabetes
-what happens
-what does/can it result in- x2
-how can type 2 be controlled- x2
obesity
-person resistant to own insulin
-blood glucose level can rise dangerously high
-can lead to blindness
-amputation of a limb
-carb controlled diet
-regular exercise-
why have cancer survival rates increased
improved treatment
able to diagnose earlier
increased screening for it
what are risk factors for cancer x5
smoking
obesity
uv exposure
viral infection
carcinogens
2 types of risk factors linked to an increased rate of disease
-aspects of a persons lifestyle
-substances kin persons body/environment
example of substance in environment that can cause cancer
radon- radioactive gas- increases risk of developing lung cancer
what is a communicable disease
disease spred from person to person via a pathogen- (eg bacterium/virus)
what is epidemiology
-do risk factors apply to communicable diseases-
studying patterns of disease to identify risk factors
-risk factors apply to all diseases
though there are some risk factors that directly cause a disease, most are caused by an…..
-what is a positive correlation, give an example, with no. of cigarettes smoked and chance of developing lung cancer
-important fact to remember about a correlation- link this to the positive correlation of cigarettes and lung cancer
interaction of a number of risk factors.
-as number of cigarettes smoked increases, risk of developing lung cancer increases
-correlation does not prove cause- a graph showing a positive correlation btwn smoking and cancer doesn’t prove that smoking cigarettes causes cancer- it suggests they are linked
what is a causal mechanism
-how does smoking increase risk of cancer
why was it accepted that smoking increases the risk of lung cancer
( look for ) a scientific explanation of how a risk factor can cause a disease
-cigarette smoke contains chemicals- carcinogens- which damage dna and increase risk of cancer
when scientists had a strong correlation btwn smoking and lung cancer AND had a causal mechanism
what is a problem with sampling
- how can this be addressed-
-not possible to sample every single person
-sample may be BIASED- may not represent whole population( eg ppl from one town may exercise less than the average/exposed to pollution only in that town)
-cannot use the results to draw conclusions about whole country
-to avoid bias- sample must be as large and random as possible
-must sample this group of people- then draw conclusions about whole population
what type of samples can we not draw conclusions from
-what do scientists plot in order to see if there’s a correlation brwn 2 factors
a small or non-random sample
-a scatter graph
how can scientists decide if a risk factor is related to a disease
-unethical to carry out experiments to find out what causes disease
-look at lifestyle habits and see if they link w/ the disease
-control all other variables that could affect findings (eg age/ exposure to other things that cause cancer)
ill health(mental + physical) can be caused by… x3
poor diet
stress
life situations eg working w/ harmful chemicals/ access to meds/ buy good food
different types of diseases may interact-
give an example that links w/ immune system
someone w/ defective immune system eg w/ HIV-more likely to suffer from communicable diseases like TB (communicable lung disease) or influenza bcse body can’t properly defend against the pathogen. One disease increases risk of another.
different types of diseases may interact-
give an example that links w/ cancer
viruses living in cells can trigger cancers
Most cervical cancers caused when HPV infects cells of cervix
-hepatitis virus causes infection in liver- virus lives in liver cells- increases chance of liver cancer
different types of diseases may interact- give an example that has to do w/ allergies-
immune reactions initially caused by a pathogen triggers allergies like skin rashes/asthma
-body infected w/ pathogen-immune system fights it off but triggers allergy- rash or asthma worsens
different types of diseases may interact
-give an example w/ mental illness
severe physical ill health can lead to depression/ other mental ilness -eg a health problem (arthiritis) impacts ability to carry out daily activities/live normally- makes them feel isolated/ depressed
or an illness that affects life expectancy causes depression
what is a pathogen
microorganism that can cause a disease when infects host
what are the
human costs of non communicable diseases x2
financial cost of disease x5
-tens of millions of ppl die each year
-ppl w/ diseases have low quality of life, shorter life, affects sufferers and loved ones
-Costs NHS alot to research + treat them - same for health services around the world
-families may move/adapt home for family member
-not able to work/dies- family gets poorer
-less ppl working= less productive workforce= negative effect on economy
-more government spending on health
how can the lifestyle of the poor increase chance of disease
why r ppl in developed countries more likely to have non communicable disease
-deprived areas more likely to smoke/ poor diet/ under exercise- increase chance of cardiovascular disease, type 2 diabetes, obesity
-non communicable diseases more common bcse ppl have higher income- buy high fat food
where does mitosis occur
why does mitosis not lead to cancer
cancer is the result of-
all over body-
tightly controlled by genes in nucleus which tell cells when and when not to divide.
-changes in cells that lead to uncontrolled growth and division (producing a tumour)
benign tumours are-
malignant cells
which type are cancers
growths of abnormal cells which are contained in one area- usually within a membrane- that don’t invade other parts of body
-invade neighbouring tissue+ spread to other parts of the body in the blood- then form secondary tumours
-malignant
how do malignant tumour cells spread
what cancers are linked to genetics x3
cells break off and spread to other parts of the body through blood stream-invade healthy tissues
-breast
prostate
large intestine
what are the risk factors for cancer linked to lifestyles x6
-smoking-contains carcinogens like tar (mouth,bowel,stomach,cervica)
-obesity (bowel,liver,kidney)
-UV exposure-from sun, sun beds (skin cancer)
-alcohol
-viral infections increase chance of certain cancers (may be spread by unprotected sex/sharing needles)
-substances in environment- radon gas- radioactive gas- releases ionising radiation which damages DNA in cells-causing uncontrolled cell division
what is a tumour
what is a carcinogen-
examples-
-abnormal growth of cells due to uncontrolled growth and division
-substance capable of causing cancer
-ionising radiation from x rays
-tar from cigarettes
-asbestos
how does uv radiation cause cancer
too much damages dna in skin cells-
mutations in the _ _ _ _ genes have been linked to an increased chance of developing breast and ovarian cancer
BRCA
what are the 5 tissues in a leaf
- epidermal tissues
- palisade mesophyll
- spongy mesophyll
- xylem + phloem
- meristem tissue
what covers top and botom of leaf and the whole plant
thin epidermal cells which form the upper and lower epidermis
what do the epidermis do-
Adaptation of upper epidermis
-what is upper epidermis covered with-
-why
-how is lower epidermis adapted for its function - 3 points
protect leaf/organz surface
-transparent- allow light to pass through to photosynthetic palisade layer below
-covered with thin, oily waxy cuticle - prevents evaporation of water from leaf surface
-has tiny pores- stomata-
-they allow CO2 to enter and O2 to leave leaf. Stomata help control amount of water vapour passing out
-therefore adapted for efficient gas exchange
what do stomata do
what do guard cells do
-the role of stomata and guard cells is
allow CO2 to enter and O2 to leave leaf. + help control amount of water vapour passing out
-control opening/closing of stomata in response to environmental conditions
– to control gas exchange and water loss.
where is palisade mesophyll
-how is it adapted for function x2
top of leaf-under epidermal tissue
-the palisade cells in the tissue have many chloroplasts- have chlorophyll to absorb light for photosynthesis
-so its at top of leaf-get most light
where is spongy mesophyll
-adaptation
-why x2
under palisade mesophyll
-full of air spaces
-Increase rate of diffusion of CO2 from spongy mesophyll to palisade mesophyll
-and rate of O2 diffusion from palisade through spongy to stomata
what does xylem do
example of substance it transports and y
-what do the phloem and xylem both help do-
transport water and dissolved mineral ions from root to stem and leaves for photosynthesis
-magnesium to make chlorophyll
-support the structure
what does phloem do
-what is the substance it transports used for x2
-what is translocation
transports dissolved sugars (from photosynthesis) from leaf to rest of plant
-sugars can immediately be used eg glucose used in respiration
OR sugars can be stored- eg as starch
-movement of food molecules through phloem tissue
-where is meristem tissue found
-why are meristems important 3 points
-growing tips- eg roots/shoots
-contains stem cells
-which can differentiate into different types of plant cells
- allowing plant to grow
what is the leaf-
-the plant organ….. x3 system is made up of
-what does the plant organ system do
a plant organ .
-leaves,
-roots
-stem
-transport substances around plant
what are root hair cells
-they are adapted for-
-how are they adapted
cells on surface of plant roots that grow into hairs
- efficient uptake of water by osmosis and mineral ions by active transport
-large s.a
the xylem is a
what is the chemical in the thick walls of the xylem
-what does this chemical do
-why do the xylem cells die
-hollow tube strengthened by lignin in the stem
-lignin
-strengthen plant
-the cell walls are sealed w/ lignin
what is translocation
what is transpiration stream
-movement of food molecules through the phloem tissue
-chain of water molecules and their movement from roots through xylem and out of leaves
what do the xylem carry
-adaptations to allow easy flow of substances x2
water + dissolved minerals(to leaf)
-end walls btwn cells broken down
-no internal structures-
phloem consists of ….-long explanantion
phloem composed of- short explanation
-what direction does transport happen in phloem
phloem vessel cells with pores/sieve plates and companion cells connected by more pores
-tubes of elongated cells w/ pores in end walls
-both directions
why are there pores in phloem cells
-why does phloem vessel cell have no nucleus and limited cytoplasm
-purpose of companion cell
so cell sap(mainly dissolved sugars) can move from one phloem cell to the next
-easier for substances to move thru
-mitochondria in companion provide energy to phloem vessel cell
what is transpiration
describe the transpiration stream
evaporation of water from cells in leaf
-water vapour diffuses through air spaces in spongy mesophyll
-and evaporates out leaf through stomata
-water pass from xylem into leaf-replace lost water
-more water drawn from root hair cells + up xylem to leaf
where does photosynthesis happen
-what is the product/s
-how is it transported
-why is transpiration important x3
in leaves
-sugar
-through phloem
-brings water to leaf for photosynthesis
-transports mineral ions needed
-evaporation of water cools leaf down esp in hot weather
factors that affect rate of transpiration x4
temp
humidity
air movement
light intensity
effect of light intensity and temp on rate of trabspiration-
*light intensity
-higher light intensity= faster rate
-high light intensity- high rate of photosynthesis
stomata open for CO2 to enter
so water can pass out of the leaf
*temp-
Higher temp= faster rate
evaporation is faster-heat means particles have more energy to evaporate
explain the effect of:
air flow
humidity
on rate of transpiration
*air flow
-more windy= faster rate
-water vapour around leaf removed-so low conc. outside- higher conc. inside= faster diffusion
*humidity
-lower humidity=more dry= faster rate
not alot of water in air. more in leaf- increases concentration gradient for diffusion
what happens to stomata when plant has a lot of water x3
what happens in hot conditions x4
-when light intensity high- plant has a lot of water- guard cells become turgid & change shape
-causes stomata to open
- CO2 diffuses in for photosynthesis
-hot conditions-plant has little water- guard cells lose water & become flaccid
-causes stomata to close
-reduces water loss by transpiration
-no photosynthesis happens
what happens to guard cells at night
-why are more stomata found under leaf
-water enters root hair cells by -
-how are the guard cell walls adapted
they are light sensitive- close at night - save water (dont lose out on photosynthesis cos none can happen)
-more shaded-cooler-less water lost
-osmosis- higher conc in soil than root hair cell cytoplasm
-thin outer walls- thick inner walls help opening and closing work
what is used to estimate transpiration rate
- how x4
potometer
-set up apparatus-
-record starting position of air bubble
-record distance moved per unit time w/ stopwatch
-keep conditions constant eg temp/humidity
-you can estimate rate of transpiration by measuring water uptake of plant- assuming water uptake directly related to water loss by leaves (transpiration)
guard cells are adapted for x2
how would you increase the humidity in a room
gas exchange + controlling water loss
-misting/spaying air with water
