B2 Flashcards
(33 cards)
Cell organisation order
Cells—tissues—organs—organ systems—organism
Tissues in the stomach
- glandular
- muscular
- epithelial
Example of an organ system and features
The digestive system:
Mouth
-mechanically breaks down food
Salivary gland
-produces amylase to break down starch
Liver
-releases bile which emulsifies fats and neutralises stomach acid
Gall bladder
-stores bile
Stomach
- churns up food
- HCL kills bacteria
- breakdown of proteins
Pancreas
-produces enzymes
Large intestine
-removes excess water
Small intestine
-moves small food molecules to blood
Rectum/anus
-gets rid of waste food
Enzymes____
Speed up chemical reactions
How enzymes break down substrates (lock and key theory)
The substrate attaches to the active site.
The substrate fits perfectly and is broken down into products
3 types of enzymes
Protease, amylase and lipase
Protease enzyme
Proteins—protease enzyme—Amino acids
Made in stomach, pancreas and small intestine
Amylase enzyme
Starch—amylase enzyme—Maltose
Made in salivary glands, pancreas and small intestine
Lipase enzyme
Lipid—lipase enzyme—glycerol fatty acids
Made in pancreas and small intestine
What does bile do
Bile emulsifies fat (breaks fat down into tiny droplets) giving a much bigger surface area making digestion faster.
Blood is made up of a fluid called___
Plasma
Plasma has 3 parts
- platelets
- white blood cells
- red blood cells
Platelets features/functions
- no nucleus
- triggers blood clotting at the sites of wounds to stop blood flowing out.
Red blood cells features/functions
- large surface area
- no nucleus
- carries oxygen to body
White blood cells features/functions
- can change shape
- has a nucleus
- Fights disease and infection
How to prepare food samples for tests
- get food sample and break it up using a pestle and montar
- transfer food to beaker and add distilled water
- stir mixture with glass rod to dissolve
- filter solution to get rid of solid bits
Test for sugars
Benedict’s test
- prepare food sample and transfer 5cm³ to test tube
- set water bath to 75℃
- add Benedict’s solution and leave for 5 mins
If sugar is present it will go from blue to green, yellow or red
Test for starch
Iodine test
- prepare food sample and transfer 5cm³ to test tube
- add a few drops of iodine solution and shake
If starch is present the colour will go from browny-orange to black or blue-black
Test for proteins
Biuret test
- prepare food sample and transfer 2cm³ to test tube
- add 2cm³ of biuret solution and shake
If protein is present it will go from blue to pink or purple
Test for lipids
Sudan III test
- prepare food sample and transfer 5cm³ to test tube
- add 3 drops of Sudan III stain solution and shake
If lipid is present the mixture will separate out into 2 layers, the top layer will appear red
Blood vessels
Arteries
- take oxygenated blood at high pressure away from the heart
- thick muscular walls
- small lumen
Capillaries
- connect arteries and veins
- thin walls
Veins
- carry de-oxygenated blood at low pressure back to the heart
- thin walls
- big lumen
- have valves which prevent back flow of blood
The heart
(VAVA)
Vena cava RA RV Pulmonary artery Pulmonary vein LA LV Aorta
Gas exchange
O2 comes into the alveoli
and diffuses from a high concentration to a low concentration in the capillary where it attaches onto haemoglobin to form oxyhemoglobin, this is then transported around the body.
CO2 diffuses from a high concentration in the capillary to a low concentration in the alveoli where it then leaves the body
Communicable diseases_____
Non-communicable diseases_____
Spread between organisms
Cannot be spread between organisms
