Organisation Flashcards
What is a tissue
Similar cells form tissues, where the cells work together to perform a specific functio
What is an organ
Group of tissues which work together to form a bigger structure called organs that peform a particular function
What is an organ system
Organs work together with other organs to create organ systems that carry out a vital function in the organisms
What is a digestive system
Explain the different toles and processes in the digestive system:
The organ system designed to efficiently digest and absorb food and any waste products
1) mechanical digestion in the mouth,stomach and small intestines
2) Absorption in the small and latge intestines transporting nutrients into the blood
3) digestive ensymes produced in the pancreas and salivary glands
4) production of bile in the liver
State all parts of the human digestive system
Mouth,salivaryglands ,oesophagus ,stomach, pancreas,liver,gall bladder,large intestines,small intestines,rectum and anus.
State different parts of the stomach
Epithelial tissue (outside)- protects stomach
smooth muscle tissue(middle) - mix and propels food
glandular tissue (inside)- produces digestive enzymes and acid
State each function of the 3 stomach tissues
1)smooth muscles contract to move food around
2) glandular tissue secretes essential enzymes and hormones for digestion
3) epithelial tissue that covers the inside and outside of the stomach
What do the muscular tissue in the stomach do
Contracts the muscles which churns the contents inside the stomach
What is an enzyme
Enzymes are biological catalyst which increase the rate of biological reactions without being changed or used up
What are enzymes made up of
Long chains of amino acids that are folded into specific shapes
What is the lock and key model
Active sites of an enzyme fits the substrate perfectly like a lock and a key, they are complementary
Explain the lock and key theory
All enzymes have a specific active site which can only bind into a specific substrate . when they bind they form a enzyme-substrate complex. An enzyme can only catalyse to one specifc type of reaction and therefore produce the products
What is the rate of enzyme reaction controlled by
Temp and PH
Explain how increasing the temp can increase rate of reaction
Enzyme and substrates will have more kinetic energy and be more likely to collide
This happens up to a point (optimum temp). After this, bonds break down as enzymes begin to denature and begin to lose their specific shape.
Once the shape of the active site changes, substrates can’t bind, no formation of enzyme substrate complexes and products
Explain how increasing the pH can increase rate of reaction
Enzymes have an optimum pH, too high or low then the bonds in the enzymes break and become denatured
Active site changes shale, substrate will not bind and enzyme substrate complexes won’t form thus no enzyme catalysing the reaction
Each enzyme have different optimum pH
Required practical
Investigating the effect of pH on the rate of reaction
1) use a pipette and prepare a spotting tile by placing a drop of iodine solution in each cavity
2) prepare a test tube containing 2xm^3 of amylase and 1cm^3 of a buffer solution with a known Ph. Place in a water bath 35°c
4) pour starch into the amylase and buffer solution and start the timer then leave it
5)every 10 seconds take a drop the solution and place it on the iodine (blue black if starch is present)
6) continue until the colour turns brick-red (maltose digested)
7)repeat experiment using buffers of different pH values to find effect ir has on rate of reaction
Why is the breakdown of starch into maltose by amylase used in the req practical
Starch can be easily detected because if added to iodine solution, it will turn blue black. If present remains brick-red
How to calculate rate of reaction
1000
Rate of reaction (s^-1) =————-
Time
Purpose of digestive enzymes
Food such as starch,protein and fat moelcules to big to pass through the small intestines into the blood. Therefore are digested so nutrients can be tarnsported across the body.
What are carbohydrases, starch and amylase
Digestive enzymes that break down carbohydrates into simple sugars.
Starch is a common carbohydrate
Amylase is a carbohydrate that breaks down starch into maltose
Amylase digests starch into the mouth a d small intetsines. It is produced in the salivary glands and small intetsines
What are proteins, protease and amino acids
Proteins: digested in the stomach by pepsin and in the small intestines by other proteases they are made up of long chain of amino acids
Protease: digestive enzymes that break down proteins into amino acids they are produced in the stomach, pancreas and small intestines
How do fats get broken down
Fats get emulsidied by bile and then they are broken down by lipases
Bile is produced by the liver, stored in the gall bladder and released into the small intestines
What is biles function
Alkaline substance that neutralises hcl from rhe stomach which creates better conditions in the small intestines so it can digest food efficiently
Additionally bile also emulsifies fat by breaking it down into smaller droplets so it has a large surface area dor lipases to work on , faster digestion.
What is lipases function
Lipase is a digestive enzyme that breaks down lipid molecules into glycerol and 3 fatty acids, in the small intestines. They are produced in the pancreas and small intetsines
Explain what happens during digestions explain the steps from mouth to the exit
Mechanical digestion occurs by the teeth which breaks it into smaller pieces. Amylase in the saliva is secreted by the salivary glands to start breaking down starch from the food into maltose.
Then it is sent down by the oesophagus to the stomach
The stomach churns and contracts the food to digest the protein with pepsin (pepsin required pH2) and the Hcl kill the bacteria.
Food enters blood stream from small intestines and passes through to the large intesines where excess water is absorbed and stored in the rectum then excreted by the anus.
Food sent towards the small intetsines where bile and enzymes are released:
Bile secreted by the liver, stored in the gall bladder released to the small intestines where it is neutralised hcl so fat can be emulsified by lipase enzymes
Digestive enzyme such as protease,carbohydrases and lipase released from the pancreas to small intestines.
Stored in the rectum and then is excreted by the anus
Required practical
Testing food samples for carbohydartes, proteins and lipids
1) break food with a pestle and motar, dissolve it distilled water then filter out any remaining solid pieces with a funnel and filter paper.
Benedicts solution for sugar:
1) Add dops of Benedicts solution containing the food samples
2) Put test tube inside a water bath at 80°c for 5 min
3) If the blue turns orange-red sugar is present
Iodine test for starch:
1) Add the food sample in the test tube then a few deops of iodine solution
2) gently shake until the bown-orange solution turns blue black
Biuret solution for protein:
1) Add biuret solution inside a test tube with food samples
2) shake gently
3) If the solution changes colour from blue to purple protein is present
Emulsion test for lipids:
1) add a few drops of ethanol to distilled water in a test tube with the food sample
2) shake gently to mix contents
3) The colourless solution will become a white cloudy precipitate (emulsion) signifying presence of lipids
What are the lungs responsible for and what happens
Responsible for gas exchange in humans,oxygen is taken in from the air and transported to respiring cells that use it to produce energy. Carbon dioxide is a waste product from respiration.
How does gas exchange take place in the lungs
Air enters the body through the mouth and nose and travels down the trachea to the lungs.
Trachea splits into 2 bronchi in each lung and each bronchus branches out into bronchioles that end in little air sacs called alveoli.
Alveoli are the exchange surface for gases in and out of the body
Where are the lungs located
Located in the thorax,selerated from the rest of the body by the diaphragm.
They are surrounded by the pleural membranes and encased in the ribcage
Contraction and relaxation of the intercostal muscles and the diaphagrm cause ventilation
What is ventilation
Movement of air in and out of the lungs and enables large volumes of gas to be exchanged.
What happens during inhalation of the lungs
1) The external intercostal muscles contract pulling the rib cage up and out.
2)The diaphragm contracts and flattens.
3)This increases the volume and decreases the pressure of the thorax.
4)Air is therefore drawn into the body.
How is gas exchanged in the alveoli
Deoxygenated blood pumped to the lungs by heart,contains lots of carbon dioxide
Oxygen in the alveoli will diffuse into the blood and carbon dioxide will diffuse out down the concentration gardient
Blood is oxygenated and pumped to respiring cells for respiration and then carvon moves back into the blood
Cycle repeats
What happens during exhalation of the lungs
1)The external intercostal muscles relax pulling the rib cage down and in.
2)The diaphragm relaxes and moves upwards.
3)This decreases the volume and increases the pressure of the thorax.
4)Air is therefore expelled from body.
