B2 Flashcards
Give three examples of tissues
- epithelial- lines the outer surface of organs and blood vessels
- muscular
- epidermal - e.g. skin and waxy covering of plants
What is the digestive system made up of?
- glands( salivary glands and pancreas)- produce digestive juices containing enzymes
- oesophagus- carries food to the stomach
- the stomach- produces hydrochloric acid
- small intestine- where soluble molecules are absorbed into the blood
- liver- produces bile which is stored in the gall bladder
- large intestine- absorbs water from undigested food to produce faeces
- rectum/anus - get rid of waste products
What is the function of bile?
Bile is an alkaline to neutralise hydrochloric acid from the stomach and it emulsifies fat to form small droplets (increases the surface area)
What is an enzyme?
a biological catalyst made of proteins (a substance that speeds up the rate of reaction without being used up)
Explain the lock and key model
- Enzymes are specific so the shape of the active site is complementary to the shape of the substrate
- Once these two are bound, the reaction takes place
What are the three types of enzymes involved in the digestive system? What are their functions?
Carbohydrase- break down carbohydrates into simple sugars
Protease- break down proteins into amino acids
lipase- break down lipids into glycerol and fatty acids.
Where are the following enzymes made:
a)amylase
b)protease
c)lipase
- amylase- salivary glands, small intestine, pancreas
- protease- stomach, pancreas, small intestine
- lipase- small intestine, pancreas
 How does temperature affect enzyme activity?
at low temperatures there is not enough energy so as the temperature increases, the rate of enzyme activity increases. Once it reaches its peak it is at the optimum temperature so after this temp, the enzyme is denatured
How does pH affect enzyme activity?
As pH increases so does the rate of enzyme activity until it reaches the optimum pH. A continued increase in pH would result in a sharp decrease as the enzyme is denatured
Why is the circulatory system a double circulatory system?
blood is pumped from the heart twice.
1. (once from the right ventricle to the lungs= pulmonary circulation
2. once from the left ventricle to the rest of the body= systemic circulation)
What is the circulatory system made up of?
- vena cava- carries deoxygenated blood from the body into the right atrium
- right atrium- top chamber on the right side
- valve- between right atrium and ventricle
- right ventricle- bottom chamber on the right side
- pulmonary artery- carries the deoxygenated blood from the right ventricle to the lungs
- lungs- gaseous exchange happens (alveoli)
- pulmonary vein- carries oxygenated blood from the lungs into the left atrium
- left atrium- top chamber on the left side
- valve- between the left atrium and ventricle
- left ventricle- bottom chamber on the left side
- aorta- pumps blood to the body
Why does the left side of the heart have much thicker walls?
the left side has to pump blood to the rest of the body at a much longer distance
What are the three blood vessels and their functions?
Arteries - carry hight pressured oxygenated blood away from the heart
veins - carry low pressure deoxygenated blood to the heart
Capillaries - carry blood close to cells so substances can be exchanged
Describe the structure of an artery
- thick outer walls and elastic tissue
- narrow central lumen
- high blood pressure
Describe the structure of a vein
- thin outer walls and elastic tissue
- wide central lumen
- valves to prevent the backflow of blood
- low pressure