B3 - Organisation and the Digestive System Flashcards
What is a tissue ?
A tissue is a group of cells with a simialr structure and fuction .
What is an organ ?
An organ is a group f tissues working togetehr for a specific funciton e.g the stomach .
What tissue does the stomach contain ?
The stomach contains muscular and glandular tissue (which releases enzymes ).
Organs are groupted together …
into organ sytems which work together to form organisms .
Food contains three main nutrients , what are they ?
- Carbohydrates (starch
- Protein
- Lipids (fats)-
All three main nutrients are large molecules , what does this mean ?
They are too large to be absorbed into the bloodstream .
-So they have to be digested ..
What breaks down large moelcules ?
- During digestion , ;arge food molecules are broken down into smaller ones by ENZYMES .
- The small molecues can then be absorbed into the blood stream .
What is the first stage of digestion food ?
- Food is chewed in the mouth .
- Enzymes in the saliva begin to digest the starch into smaller sugar molecules .
What is the second stage of digestion food ?
2The food then passes down the oesohagus into the stomach .
-In the stomach , enzymes begin the digestion of protiens .
What does the stomach contain how does it aid digestion ?
-The stomach contains hydrochloric acid , which helps the enzymes to digest the proteins .
What is the third stage of digestion food ?
- Food spends several hours in the stomach .
- The churning aciton of the stomach msucles cntrsact turns the food into a fluid increasing the surface area for enzymes to digest .
What is the fourth stage of digestion food ?
The fluid now passes into the small intestine
What is the fifth stage of digestion food ?
-At this point , chemicals are released into the small intenstine from the liver and the pancreas .
What is the sixth stage of digestion food ?
- The pancreas releases enzymes which continue the digestion of starch and protein .
- They also start the digestion of lipids .
What is the seventh stage of digestion food ?
The liver releses bile which helps to speed up the digestion of lipids .
-Bile also neutralises the acid released form the stomach .
What is the eighth stage of digestion food ?
Fluid makes it way thorugh the rest of the small intenstine release ezymes to continue the digestion of proteins and lipids .
What is the ninth stage of digestion food ?
In the small intenstine , the small food molecules produced by digestion are then absorbed into the blood stream by diffusion or active transport .
What is the tenth stage of digestion food ?
Now the fluid makes it way through the large intenstines where water is absorbed into the blood strem .
What is the eleventh stage of digestion food ?
Finally faeces is released from the body .
Summary of wht the digestive system does .
In the digesitve systme , large food molecules are digested into smaller moelcules and then the products of digestion are then absorbed into the blood stream .
What are the products of digestion used for ?
- Now the products of digestion are then usedby the body to build new carbohydrates , lipdis and portiens .
- Some glucose produces , is used in respiration .
What is one adaptaation of the small intestine ?
- Very long , length of 5m
- This provides a bery large surface area dfor asorption of the products of digesiton .
Give one adpatation of the viili .
- Interior of small intenstine is covered in villi .
- Villi massivley increase he surface areea for absorption of moelcues .
- Surface of villi has microvilli , increase the surface area further .
Giev another adpatation of the villi .
- Villi have a very good blood supply .
- So this rapidly removes the products of digestion .
- Thsi icnreases the concentration gradient .
Give the last adaptation of the villi .
Villi also have a thin membrane , ensuring short diffusion path .
ALL these features mean there is a rapid rate of diffusion .
Any molecues which cannot be absrbed by diffusion…
can be absorbed by active transport .
What are enzymes ?
Enzymes catalyse (speed up) chemical reactions . -Enzymes are large protein molecule swhich have a groove on their surface called the active site .
What is the active site ?
The active site is where the subtrate (molecule enzyme breaks down ) attaches to .
fiitting enzyme
- Substrate fis into the enzyme active sight .
- The enzyme now breaks down the substrate into the products .
What happens if the enzyme does not fit ?
If the enzye does not fit into the active site . The enzyme cannot break down the substrate .
ENZYMES ARE SPECIFIC to the substarte and must FIT PERFECTLY into the active site .
draw the lock and key theory .
.
Enzymes can also join small mollecules togteher .
.
What do enxymes contol
The metabolism-the sum of all the reactions in a cell or in the body .
Different metabloic reactions ;
-Builidng larger molecules from lots of smaller ones - builidng starch from glucose . Plants make glucose - this and nitrate ions make aminoa cid .
another metabolic reaction ;
changin one molecul e into another , chaging one ismple sugar into another glucose to fructose .
last metabolic reaction
breaking down large moelcules into smaller ones , dbreaking catbs proteins liipdis doen into smaller moelecules .
What are porteins broken down by , where are they found .
- Proteins are longn chains of chemiclas called amino cids .
- they are broken down by proteases , found in stomach , pancreas and small intenstine . .
- Protease enzymes convert protein into invididual amino acids which arethen absorbed into bloodstream .
- then joined ogther in a different order to make human proteins .
Starch breaking donwn
-Starch is a carbohydrate .
-when Starch is digested we produce simple suagrs . They are broken down by enxymes called carbohydrases , STARCH is broken down by amylase .
AMYLASE found in saliva and pancreatic fluid .
-Starch consists of a chain ofglucose moelcules .
Lipids breakindg down
-A lipid molecule consisgts of a moleucle of glycerol attached to three moelcules of fattya cids .
Lipds digetsed by enzyme lipase . Producing glycerol and fatty acids .
-Lipase found in pancreatic fluid and small intenstine . .
What does the digestion of lipids also include .
DIgstion of lipdis also invlovles bile .
- Bile is mde in the liver and stored in the gall bladder .
- blile helps to speed up the digestion of lipids by emusifying the fats but IS NOT an enzyme .
What does bile do ?
- Bile coneverts large lipdi droplets into smaller dorplets .
- Bile emulsifies lipis - masiely incresing the surface area if lipid droplets .
- this increases the rate of lipid breakdown by lipase .
- Bile is also alkaline , allowing it to neutralise stomach acids , creating alkaline condition in the small intensitne , increasing rate of lipid digestion by lipase .
What is a carbohydrate ?
Carbohydrates provide us with the fuel that makes all of the other reactions of life possible . COntais chemical elemnt carbon , hydrogen and oxygen .
-Made up of units of sugars .
MORE FAX ABOUT CARBOHDYRATES.
-sOME ONLYC ONTAIN ONE SUGAR UNTI LIKE GLUCOSE .
-Some got two like sucrose , Tthese small carbohydrta euntisl referred to a smile sugars .
-co.mples carbs like starch and cellulos made up of long chains bonded togtehr .
Carb rich foods likebread poatoes and rice
-broken down into lucose used in cellulr repsiration and metabloci reactions in cell also support material in plants carb cellulose is
What are lipids ?
Lipids are fats (solids and oils (liquids)
- MOst efficent strore in your bod and important source of energy in diet ,
- made of carbon hydrogen oxygen
- importnnt for hormoes and nervousy sytem .
MORE FAX ON LIPIDS .
-Lipids are made up of thee moelcues of fatty acids joined togetehr by glycerol .
Glycerol always same but fty aicds vary ..
-Lipid rich food is liek cheese butter .
What are proteins ?
-Proteins are used fo rbuilidng up the cells and tissues of your body as well as basis of enzymes .
-Found in hai rna dnials and muscles .
Made oc Carbon hdyrogen an oxygen .
-R[Protein food - fish , pulses cheese
MORE FAX ON PROTEINS >?
- Mde up of logn chains of small units called aminoa cids
- chains of amino acid senstive to ph and emp , if the so can be eaily broekn , if it los the shape and cannot fnction in anymore of cells IT HAS DENATURED .
RQP hazard .
Safety goggles msut be worn as chemicals in these tests are potentially hazradous .
What is stage one for FOOD TEST rqp ?
1.Take the food samplea ad mortar and pedtle . Grindwith motar and pestle , using distilled water , we want to make a paste .
What is stage two for FOOD TEST rqp ?
ONLY FOR SUGARS , STARCH AND PROTEIN
Tranfer the paste to a beaker and addd more distille water . Stir , so the chemicals in the food dissolve in the water .
- Filter the solution to remove the suspended food particles .
- Now test for chemicals present .
What is the test for starch ?
- Add 2 cm cubed of food solution in est tube .
- Add a few drops of iodine solution which is an oragne colour ..
- If starch is present , iodine turns blue-black . If no starch present , idoine solution stays orange .
What is the test for sugar ?
-Add 2 cm cubed of Benedict’s solution , which is a blue colour .
-Placce the test tube the contaninig our solution into a beeaker ,
-HALF fill the beaker with hot water from kettle .
After five minutes colour change .
-The color chane will give approx amount og f suagr present but cannot tell exact amout .
Colour changes for sugar test ;
green shows there is a small amount of sugar
yellow shows there is more sugar present
brick red colour shows ltos of sugar present
what do scinetists call these sugars
non redcugins sugars like sucrose .
What is the test for protein .
add two cm cubed food solution
and two cm cubed biruet solution - a blue colour .
If protiens present will go purple lilac colour .
Stage one for lipid test
-grind food with mortar and pestle , but don’t filter solution when etsting for lipds .
As lipid molecues can STICK to filtr paper .
Stage two
- Add two cm cubed food soluton into a test tue , add distilled water ew drops and few drops of ethanol .
- Gently shake solution , if lipids present a white cloudy emulsion forms .
hazrd with lipid test .
Ethanol is highly flammable , so important naked falmes are not prersent .
Check enzyme sheet star one , what does it show ?
- As we increase the temperture , the activity of the enzyme increases (the reaction gets aster .)
- This is because the enzyme and substarate are moving fasteer , so there are more collisions per second betwen substarte and active site .
Check enzyme sheet start two , what does it show ?
- At a certain temperature , the enzyme is workng at the fastest rate possible , that is called the OPTIMUM TEMPEATURE .
- At this point , there is the maximum frequency of successful collisions beween the substrate and active site .
What is the optimum temperature for human enzymes ?
37 degrees , human body temperatrue .
Check enzyme sheet star three , what does it show ?
- As we uncrease the temperatrue , past the optimum , then the activity of the enzyme rapidly decrease to zero .
- This is because high temperatrue causes the enzyme moelecule to vibrate and the shape of the acitve site changes .
- Now the substrate no longer fits perfectl into the active site . The active site is denatur e. The enzyme can no longer catalyse the reaction .
Check enzyme sheet ph , what does optimum ph show .
The enzyme has an optimum Ph where the activity is maximum
What happens if we make the Ph more acidic or more alaline .
Then the activity drops to xero .
-As the active site deatures if the conditions are too acidic or too alakube .
every enzyme has a s[ecific optimum Ph it works best at .
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