organisation Flashcards
what are cells?
the basic building blocks that make up all living organisms
what is a tissue?
a tissue is a group of similar ccells that work togther to carry out a particular function
give 3 examples of mammal tissues and the ir functions
1) muscular tissue - contracts to move whatever its attatched to
2) glandular tissue - makes and secretes chemicals like enzymes and hormones
3) epithelial tissue - covers some parts of the body
what is an organ?
group of different tissues that work togther to perform a certain function
what are the 3 tissues the stomach is made up out of? describe their functions
1) muscular tissue - moves the stomach wall to churn up the food
2) glandular tissue - makes digestive juicess to digest food
3) epithelial tissue - covers the outside and inside of the stomch
what is an organ system?
a group of organs working together to perform a particular function
what are the 5 organs that make up the digestive system? describe their functions
1) glands - produce digestive juices
2) stomach and smal intestines - digest food
3) liver - produces bile
4) small intestine - absorbs soluable food molecules
5) large intestine - absorbs water from undigested food leaving faeces
what is a catalyst?
a catalyst is a substance which increases the speed of a reaction, whitout being changed or used up in a reaction
what is an enzyme?
a biological catalyst, a large protein, made up out of chains of amino acids folded into unique shapes, which enable the enzymes to do their jobs
the lock and key model is a simpler version of how enzyme action works, in reality what is the difference?
The active site changes shape slightly as the substrate binds to it, to get a tighter fit.
This is called the ‘induced fit’ model of enzyme action
Increasing the temperature increases the rate of enzyme action, but what happens if it gets too hot?
some of the bonds holding the enzyme together break, which changes the shape of the enzymes active sight, so the substrate won’t fit anymore. this enzyme is denatured
what happens if the ph is too high or too low?
it will interfere with bonds holding the enzyme togther, changing the shape of the active site, and denaturing the enzyme
what is the method for the practical on investigating the effect of pH on enzyme activity?
1) put a drop of iodine solution into every well on a spotting tile
2) place a bunsen burner on a heatprood mat, a tripod and gauze over the bunsen burner, an dthen heat the water until its 35 degrees. keep temp constant throughout the experiment
3) use a syringe to add 1cm cubed amylase solution and 1cm cubed of a buffer solution
4) use a different syringe to add 5 cm cuned of a starch solution to the boiling tube
5) immediately start the stop clock
6) use continuous sampling to record how long it takes for the amylaze enzyme to break down all the starch
what is the method for the practical on investigating the effect of pH on enzyme activity?
1) put a drop of iodine solution into every well on a spotting tile
2) place a bunsen burner on a heatprood mat, a tripod and gauze over the bunsen burner, an dthen heat the water until its 35 degrees. keep temp constant throughout the experiment
3) use a syringe to add 1cm cubed amylase solution and 1cm cubed of a buffer solution with a pH of 5
4) use a different syringe to add 5 cm cuned of a starch solution to the boiling tube
5) immediately start the stop clock
6) use continuous sampling to record how long
7) repeat this experiment with buffer solutions of different pH values, to see how pH affects the time taken for startch to be broken down
8) remember to control any variables each time to make it a fair test
how do you use continuous sampling in the enzyme activity practical?
use a dropping pipette to take a fresh sample from the boiling tube every 30 seconds and put a drop into a well. when the iodine solution remains browny-orange, starch is no longer present
rate of reaction =
1000 / time
why do big molecules like startch, proteins and fats need to be broken down into smaller molecules by enzymes?
they are too big to pass through the walls of the digestive system
What breaks down starch? into what?
amylase - maltose and other sugars
where is amylase made? (3 places)
- salivary glands
- pancreas
- small intestine
what breaks down proteins? into what?
protease - amino acids
where is protease made? (3 places)
- stomach
- pancreas
- small intestine
what breaks down lipids? into what?
lipase - glycerol and fatty acids
where is lipase made? ( 2 places)
- pancreas
- small intestine
where is the bile:
1) produced
2) stored
3) released into
1) liver
2) gall bladder
3) small intestine
why is bile alkaline?
the hydrochloric acid in the stomach makes the pH too acidic for enzymes in the small intestine to work properly, the bile neutralises the acid and makes the conditions alkaline. The enzymes in the small intestine work best in these alkaline conditions
what is the main purpose of bile?
to emulsify fat - so it breaks down fats into tiny droplets giving a bigger surface area of fat for the enzyme to work on, which increases the rate of reaction
purpose of the salivary glands
to produce amyalse enzyme in saliva
purpose of the liver
to produce bile which neutralises stomach acid and emulsifies fat
purpose of the gall bladder
where bile is stored before being released into the small intestine
purpose of the large intestine
excess water is absorbed from the food
prpose of the rectum
where the faeces are stored before they leave through the anus
purpose of the stomach (3)
- pummels food with muscular walls
- produces the protease enzyme, pepsin
- produces hydrochloric acid to kill bacteria and give the right pH for the protease enzyme (ph2)
purpose of the pancreas
produces protease, amylase and lipase enzymes and releases them into the small intestine
purpose of the small intestine
produces protease, amylase and lipase enzymes to complete digestion
where digested food is absorbed out of the digestive system into the blood
how do you prepare a food sample?
- break up a piece of food with a pestle and mortar
- transfer to a beaker and add some distilled water
- give stir with glass rod to dissolve some of the food
- filter the solution with a funnel lined with filter paper to get rid of the solid bits of food
what test is used for sugars?
benedicts test
give the 5 steps of testing with sugars
1) prep food sample, and transfer 5 cm cubed to test tube
2) prep a water bath set to 75 degrees C
3) with a pipette drop 10 drops of some benedicts solution to bath
4) place test tube in bath in a test tube holder and leave for 5 mins, making sure tube is pointing away from you
5) if food sample contaisn sugar it will go from blue to trafic light cols
what test is used startch?
the iodine test
give the 2 steps of testing for startch?
1) make food sample, and transfer 5cm cubed to test tube
2) add afew drops of iodine solution and gently shake tube to mix contents
if starch is present the col of solution will go from browny-orange to black or blue-black
what test do you use for proteins?
the biuret test
give the 3 step method of testing for proteins
1) prep sample of food and transfer 2cm cubed to test tube
2) add 2 cm cubed of biuret solution to the sample and mix the contents of the tube by gently shaking it
3) if the food sample contains protein col will go from blue to purple
what test is used for lipids?
sudan III
what is the 3 step method for testing for lipids?
1) prep sample ( no need to filter) transfer 5cm cubed into test tube
2) use pipette to add 3 drops of Sudan III stain solution and gently shake tube
3) if lipids are present solution will separate to two layers - top layer will be bright red
the lungs are in what part of the body?
the thorax
what kind of membranes are the lungs surrounded by?
pleural membranes
describe the journey of air to gas exchange
The air that you breathe goes through the trachea, and this splits into two tubes called bronchi, one going to each lung. The bronchi split into progressively smaller tubes called bronchioles. The bronchioles end at small bags called alveoli, where the gas exchange takes place.
describe the blood passing next to the alveoli before gas exchange
it has just returned to the lungs from the rest of the body, contains lots of carbon dioxide and very little oxygen
describe gas exhange ( in the lungs)
Oxygen diffuses out of the alveolus (where its at a high concentration) into the blood (where its at a low concentration)
Carbon dioxide diffuses out of the blood (where its at a high concentration) and into the alveolus (where its at a low concentration ) it is now ready to be breathed out
describe gas exhange (in body cells)
when blood reaches body cells the red blood cells release oxygen (high conc) and diffuses into body cells (low conc)
simultaneously, carbond dioxide diffuses out of the body cells (where there is a high conc) and into the bllod (low conc) it is then carried back to the lungs
describe what is meant by “the double circulatory system”
The circulatory system is made ip of 2 circuits joined together:
1st - reight ventricel pumps deoxygenated blood to the lungs to take in oxygen, the blood then returns to the heart
2nd - left ventricle pumps oxygenated blood around all the other organs of the body. The blood gives up its oxygen at the body cells abd the deoxygenated blood returns to the heart to be pumped out to the lungs again
what are the walls of the heart mostly made of?
muscle tissue
why does the heart have valves?
to make sure that blood flows in the right direction, not backwards#
what are the 4 heart chambers?
right atrium, right ventricle, left atrium and left ventricle
describe blood flow in 5 steps
1) blood flows into the 2 atria from the vena cava and the plumonary vein
2) the atria contract pushing the blood into the ventricles
3) the ventricles contract forcing the blood into the plumonary artery and the aorta and out of the heart
4) the blood then flows to the organs through the arteries and returns through veins
5) the atria will fill again and the whole cycle will start over
what is the purpose of the coronary arteries?
providing the heart with its own supply of oxygenated blood
describe the hearts natural pacemaker?
a group of cells in the right atrium which produce a small electrical impulse which spreads to the surrounding muscle cells, causing them to contract
what can be used if a patient has an irregular heartbeat?
an artifical pacemaker - a little device that is implanted under the skin and has a wire going to the heart. it produces an electric current to keep the heart beating regularly
what do arteries do?
carry blood away from the heart
what do capillaries do?
they are involved in the exchange of materials at the tissues
what do veins do?
carry blood to the heart
describe the arteries
- heart pumps blood out at high pressure, so they are strong and elastic
- the walls are thick compared to the size of the lumen
- contain thick layers of muscle for strenth and elastic fibres which allow them to stretch and spring back
describe the capillaries
- arteries branch into capillaries, they are very tiny
- carry blood really close to every cell in the body to exchange substances with them
- have permebale walls, so substances can diffuse in and out
- supply food and oxygen and take away waste like CO2
- usually only 1 cell thick
describe veins
- capillaries join up to form veins
- blood at lower pressure, so walls aren’t as thick as arterty walls
- bigger lumen to help blood flow despite the lower pressure
- have valves to help blood flow in right direction
rate of blood flow =
volume of blood/ number of minutes
give 2 ways white blood cells can defend against infection:
1) phagosytosis - englufing the microrganism by changing shape
2) producing antibodies to fight microrganisms, and antitoxins eto neutralise any toxins producede by microrganisms
what is coronary heart disease?
when the coronary arteries get blocked by the build up of fatty deposits leading to narrowing of the arteries, which causes the blood flow to be restricted, and the lack of oxygen getting tot he heart can result in a heart attack
what are stents?
tubes inserted insude arteries which keep them open making sure blood can pass through to the heart muscles, which keeps the persons heart beating
what are the positives and negatives of stents?
positives:
- lowers risk of heart attack in person with coronary heart disease
- effective for a long time
- recovery time after surgery is relatively quick
negtaives:
- risk of complications during operation
- risk of infection from surgery
- risk of thrombosis (blood clot developing near stent)
Too much LDL cholestrol in a persons bloodstream can lead to…
build up of fatty deposits in arteries, leading to coronary heart disease
what are statins?
drugs that reduce the amount of LDL cholestrol present in the bloodstream
what are the advantages of statins?
- reducing the amount of LDL cholestrol reduced the risk of strokes, coronary heart disease and heart attacks
- increases HDL cholestrol in blood, a beneficial type, which can help remove LDL from blood
- some studies have suggested they may also help preevnt some other diseases
what are the disadvantages of statins?
- long term that must be taken regularly, thre is a risk someone could forget to take them
- can cause sideffects (headaches, kidney failure, liver damage and memory loss)
- effect isn’t instant, takes time for their effect to kick in
if a patient has heart failure, what options may a doctor consider?
- heart transplant if a suitable donor organ is avaliable, and procedure is appropriate
- an artificial heart
what are artificial hearts, and what are they used for?
mechanical devices that pump blood for a person whose own heart has failed. They are usually a temporary fix to keep a person alive while a donor heart can be found, or to help a person recover by allowing the heart to rest and heal
what is the advantage of an artificial heart?
they are less likleu to e rejected by the bodys immune system, than a donor heart. This is because they are made from metals and plastics, so the body does not recognise them as foreign and tries to attack them as they would with a living tissue
what are the disadvantages of artifical hearts?
- surgery to fit one can lead to infection and bleeding
- don’t work as well as natural ones, parts could wear out or electrical motor could fail
- blood dosen’t flow through as smoothly , which can cause blood clots, and consequently strokes
- patients has to take blood thinning drugs, which could cause complications with bleeding if they are hurt in an accident
whaht damages heart valves?
heart attacks, infection or old age
what can happen when heart valves become damaged?
valve tissue may stiffen, so it won’t open properly, or it may become leaky allowing blood to flow in both directions, and consequently the blood dosen’t circulate as efficently as normal
how can severe valve damage be treated?
by replacing the valve withe ethier biological valves, or mechanical valves
(less drastic than heart transplant, but still major surgery and risk of blood clots)
what is artifical blood?
a blood subsitute (eg a saline solution) which is used to replace the lost volume of blood.It can keep a patient alive even if they have lost 2/3s of their red blood cells, giving the patient more time to produce new ones
what happens if the artifical blood cannot give the person enough time to produce new red blood cells?
they will need a blood transfusion
define health
the state of physical and mental wellbeing
what is a communicable disease?
those that can be spread from person to person, or between animals and people
they are contagious and infectious diseases
what are non-communicable diseases?
those that cannot spread between people or between animals and people
why do people with probelms wth their immune system have an increased chance of suffering from communicable diseases such as influenza?
their body is less likleu to be able to defend itself against the pathogen that causes the disease
some types of cancers can be triggered by being infected by certain types of …….
(give some examples)
hepatitius virus - increased chance of liver cancer
HPV - can cause cervcal cancer in women
immune system reactions in the body caused by a pathogen can sometimes trigger alergic reactions such as…
- skin rashes
- worsened astmah symptoms
why may a mental health problem, such as depression be truggered if somone is suffereing from severe physical health problems?
because it can impact the persons ability to carry out everyday activities, or lower life expectancy
what factors, other than disease can affect your health?
- lifestyle
- life situation
- diet
- stress
what is a risk factor for disease?
Something that is linked to an increased liklihood that a person will develop a disease during their lifetime.
give an example of a risk factor that would be an aspect of a persons lifestyle?
how much the individual exercises
give an example of a risk factor that would be the prescence of a certain substance in the environment?
air pollution
give an example of a material that would be a risk factor for illness?
asbestos fibres ( later life cancer)
on what 3 levels do risk factors have impacts?
locally, nationally and globally
In developed countries what kind of diseases are more prevalent and why?
Non-communicable, because people have a higher income and can buy high fat food
Nationally, people from deprived areas are more llikley to smoke, have a poor diet, and exercise - how does this impact the national health?
There would be a higher incidence of cardiovascular disease, obesity, and type 2 diabetes.
what impacts the local incidence of diasease?
Your individual choices.
Explain what diseases smokung has been proven to directly cause, and why?
- Cardiovascular disease, lung disease, lung cancer
- because it damages the walls of the arteries ance cells in the lining of the lungs
It is thought that obesity can directly cause type 2 diabetes, why is this?
It makes the body less sensitive or resistant to insulin meaning that it struggles to control the levels of glucose in the body.
How can drinking too much alcohol impact human health?
It can cause liver disease and affect brain function by damaging the nerve cells in the brain causing it lose volume
Doing what 2 things whilst pregnant could cause health probelms for the unborn baby?
smoking and drinking alcohol
What are carcinogens? give an example.
things that can cause cancer
eg. ionising radiation
exposure to certain substances or radiation can cause…what?
cancer
Risk factors are identified by correlations in data, but corellations do not always equal….
cause
what is the human cost of non-communicable diseases?
- millions of people around the world die per year
- lower quality life
- shorter lifespan
- impact is not just upon the sufferers but loved ones too
what is the fiancial cost of non-communicable diseases?
- very expensive for NHS ( and other health organistaions around the world) to research them
- families may have to move or adapt tehir home
- if family member gives up job or dies, there will be a lower income
- reduction in ppl working impacts countires economy
what types of cancer is smoking considered a risk factor for?
lung, mouth, bowel, stomach and cervical cancer
what types of cancer is obesity linked to?
bowel, liver and kidney cancer
what people are at risk of skin cancer due to UV exposure?
- people often exposed to sun / spend lots of time outside
- people who live in sunny climates
- people who frequently use sun beds
what kinds of infection puts you at a higher risk of developing kindey cancer?
Hepititus B, and Hepititus C
Viral infection is a risk factor for cancer, what are some examples of lifestyle choices that increase a persons likelihood of being infected with the virus?
- unprotected sex
- sharing needles
describe how genetics can be a risk factor for cancer.
- You may inherit faulty genes which make you more suseptible to cancer
mutations in what type of genes have been linked with a higher likelihood of developing breast and ovarian cancer?
BRCA
give 3 examples of plant organs
stems, roots, leaves
what are the 5 plant tissues?
1) Epidermal tissue
2) palisade mesophyll tissue
3) spongy mesophyll tissue
4) xylem and pholem
5) meristem tissue
which tissue covers the whole plant?
epidermal tissue
In which part of the leaf does the most photosynthesis happen?
palaside mesophyll tissue
describe the spongy mesophyll tissue
in the leaf, contains big air spaces to allow gases to diffuse in and out of cells
what is the purpose of the xylem and pholem?
to transport things like water, mineral ions and food around the plant
where is the meristem tissue found?
what is it able to do?
- tips of shoots and roots
- differentiate into different types of cells allowing the plant to grow
what 4 tissues does the leaf contain?
epidermal, mesophyll, xylem and pholem
why are the epidermal tissues covered in a waxy cuticle?
to reduce water loss by evaporation
why is the palaside mesophyll tissue layer nearer the top of the leaf?
because it has lots of chloroplasts, in which photoshynthesis happens, they need to be near the top of the leaf to get the most light
the xylem and pholem form a network of……
….. vascular bundles
xylem and pholem deliver what to the leaf, and what do they take away?
deliver: water and other nutrients
take away: glucose (produced by photosynthesis)
how are the tissues adapted for efficent gas exchange?
- lower epidermis full of little holes called stomata, which let CO2 difuse directly into the leaf
- opening and closing of stomata controlled by guard cells which respond to environmental conditions
- air spaces in spongy mesophyll tissue increase the rate diffusion of gases
what is the purpose of phloem tubes?
- to transport ( in both ways) food substances made in the leaves to the rest of the plant for immediate use or for storage
where does translocation happen?
in the pholem tubes
describe the structure of phloem tubes
- made of columns of elongated living cells with samll pores in the end walls to allow cell sap to flow through
what is the purpose of the xylem tubes?
to carry water and mineral ions from the roots to the stem and leaves
what is the structure of the xylem tubes?
made up of dead cells joined end to end with no end walls between them and a hole down the middle
what material are xylem tubes strengthend with?
ligin
what is transpiration caused by?
evaporation in the leaf causes there to be a slight water shortage, so more water is drawn up from the rest of the plant through the xylem vessels to replace it, this in turn means more water is drawn up from the roots so there is a constant transpirtaion stream through the plant
transpiration is just a side effect of the way leaves are adapted for photosythesis. Explain how this is…
They must have stomata so they can exhange gases easily, because there is a higher conc of water inside the plant than the air outside the water escapes from the leaves through the stomata by diffusion.
what are the 4 main things the transpiration rate is affected by?
- light intensity
- temperature
- air flow
- humidity
how is the transpiration rate affected by light intensity?
why is it affected in this way?
- the brighter the light, the faster the transpiration rate
because the stomata begin to close as it gets darker, because photosynthesis can’t happen in the dark so they don’t need to be open to let Co2 in. When the stomata are closed, very little water can escape
how does the temperature affect the transpiration rate?
the warmer it is, the faster the transpiration rate
how is the transpiration rate affected by air flow?
why is it affected in this way?
- the better the air flow around the leaf the greater the transpiration rate
if the water flow around a leaf is poor the water vapour just surrounds the leaf and soesn’t move away, this means diffusion dosn’t happen as quickly ( smaller conc gradient)
if there is good air flow, water vapour is swept away maintaing a lower conc of water outside the leaf, so diffusion happens quicker
how is the transpiration rate affected by humidity?
why is it affected in this way?
the drier the air around the leaf the faster the transpiration rate
similar to air flow, if the air is flow there is already quite a bit of water in it already so there is a smaller concentration gradient, and therfore a slower rate of diffusion, and transpiration
you can measure the rate of transpiration by measuring the uptake of water by the plant, why?
because you can assume the water uptake by the plant is directly related to water loss by the leaves (transpiration)
describe guard cells…
- kidney shape that opens and closes the stomata
- thing outer walls and thickened inner walls making the opening and closing work
- sensitive to light
- close at night to save water without losing out on photosynthesis
what are guard cells adapted for?
gas echange and controlling water loss within a leaf
what happens to the guard cells when a plant has lots of water?
they will fill up with the water, and go plump which causes the stomata to open so gases can be exchanged for photosynthesis
what happens to the guard cells when the plant is short of water?
the guard cells become flacid making the stomata close which helpps the plant not loose too much water vapour
