B2 Organisation Flashcards
Adaptations of alveoli for gas exchange?
-l’âge surface area to volume ratio
- thin walls
-good ventilation
-good blood supply
Label heart
-
Pathway of blood starting from lungs
-lungs to pulmonary vein to left atrium
- through bicuspid valve into left ventricle-ventricle contracts and pushes flood out of aorta to the body
-de oxygen blood from body enters through right atrium through vena cave
- through tricuspid valve into right ventricle
- through pu,monary artery to lungs
What is a tissue?
A group of cells of similar structure working together for a specific function
What is an organ?
Made from a group of tissues working tg to perform a function
What is an organ system?
A group of organs with related functions working together to perform body functions within the organism
Name 3 tissues in the stomach
Glandular- secretes enzymes and stomach acid
Muscle - allows contraction
Epithelial- lines the stomach
What is an enzyme?
Biological catalyst that speeds up reactions without being used up
Name and the function of each body part in the digestive system
Mouth: mechanical digestion to increase surface area of food
Salivary glands: secrete amylase to break down starch
Oesophagus: the tube that connects mouth to stomach, peristalsis occurs to push food down
Stomach: protease enzymes are secreted, hydrochloric acid provides a suitable pH for enzymes and destroys pathogens
Liver: bile is produced, neutralises stomach acid
Gall bladder: bile is stored here
Pancreas: amylase, protease and lipase are produced here before the small intestine
Small intestine: acidic acid is neutralised and enzymes complete chemical digestion, food and water are absorbed by villi
Large intestines: remaining water is absorbed, faeces formed here
Rectume and anus: egestion
What is metabolism?
The sum of all reactions in the body
Describe how an enzyme works?
The substrate bind to the active site
What is the effect of temperature on an enzyme?
The enzyme works fastest at the optimum temperature (37(body temp))
As temp increases ,rate increases and if it becomes too hot then the bonds in the amino acids break and the enzyme is denatured, as the shape of the active site changes
Effect of pH on enzymes?
The optimum pH for most enzymes is 7, but some have a lower optimum (like in the stomach acid)
Is the pH is too high or too low the binds of amino acids can break the proteins and change the active site, therefore denaturing
RP: investigating the effect of pH of the rate of reaction of amylase (tile drops) METHOD
1)Place drops of iodine in down on the tiles
2) label a test tube w the pH
3) add the starch solution to the amylase and add pH buffer solution
4) free 10 senids place one drop of the mixture on the iodine
5) wait another 10 seconds and add another drop to the nest drop of iodine
6) repeat until the iodine remains the same colour
How can the iodine tile RP be improved?
Control the temp w a water bath
Take reading at shorter time intervals
Which enzymes break down carbohydrates? Give an example in the body
Carbohydrase: converts carbs into simple sugars
E.g amylase = starch to glucose in saliva
What enzymes break down proteins? Give an example in the body
Proteases: converts proteins into amino acids
E.g : pepsin in the stomach
What enzymes break down lipids? Give an example in the body
Lipases : converts lipids into glycerol and fatty acids
E.g pancreas and small intestine
What is the food test for starch? What is the result?
Iodine: turns black /blue
What is the food test for protein? What is the result ?
Biuret test! Turns purple
What is the food test for lipids? What is the result?
Ethanol : turns cloudy
Sudan III: red layer
What is the role of bile?
An alkaline solution that neutralises hydrochloric acid from the stomach
It emulsifies large drops of fat into smaller ones
Describe the Benedict’s test for sugars
1) set up a water bath with a Bunsen burner
2) add the food sample in a test tube and put it in the water bath
3) add a few drops of Benedict’s solution
4) wait 5 minutes and note down colour changes
Describe the iodine test for starch
Add the food sample to a tube
Add a few drops of iodine
Note down colour change
