Topic 2 Flashcards
What is metabolism
sum of all chemical reactions in the body
Job of Salivary glands and pancreas Stomach Small intestine (and adaptation) Liver Large intestine
produce enzymes to break down food
protease to break down food
Absorption of nutrients into blood
Adapted to have a large SA as it is covered in villi. Good blood supply and short diffusion to the blood vessels. This greatly increases diffusion and active transport from the small intestine to blood
produces bile
=> gall bladder
=> Neutralises acid
=> Emulsifies fat
absorbs water
What are enzymes?
Biological catalysts
Made of protein
Describe lock and Key method (3m)
The shape of substrate is complementary to shape of active site
=> form a enzyme-substrate complex
=> as they are specific to each other
Once bound, products released
Factors that affect enzymes
Temperature:
Body is 37 degrees
Rate of reaction will increase as temp increases
=> if the temperature goes too high then it will rapidly decrease rate of reaction until it stops
=> Becomes denatured
=> substrate no longer fits in
pH:
Optimum for body is 7pH
If pH gets too high/ low => forces holding amino acids will break
=> changing shape of active site
=> denatured
Job of:
Carbohydrase
Amylase
Protease
Lipases
Carbohydrases break down carbohydrates
=> to simple sugars.
Amylase is a carbohydrase which breaks down starch.
Proteases break down proteins
=> to amino acids.
Lipases break down lipids (fats)
=> to glycerol and fatty acids.
Use of Bile and why it is useful
It is alkaline to neutralise HCL acid from stomach
Emulsifies fat to form droplets which increase SA
Alkaline conditions + Large SA
=> INCREASE RATE of fat broken down by lipase
How does gaseous exchange occur (4m)
Air passes into lungs through the trachea
=> trachea contains rings of cartilage preventing trachea from collapsing during inhalation
Trachea splits into 2 smaller tubes called Bronchi
- Then sub divides into smaller tubes called bronchioles
At the end of bronchioles there are air sacs called alveoli
Alveoli- where gases diffuse in and out of the bloodstream (site of gas exchange)
Adaptation of this process
Millions of Alveoli + spherical shape- large surface area
Thin walls so diffusion path is very short
Very good blood capillary supply
Once oxygen is diffused it is removed rapidly- ensures steep conc. gradient
We increase the rate of diffusion
Bring fresh oxygen and take away Co2
This makes conc. gradient high for gases
=> increases rate of diffusion
How does blood pump around the body (4m)
Left ventricle pumps blood around the entire body (more muscular)
Right ventricle only pumps blood to the lungs (less muscular)
4 chambers (R Atrium, L, R ventricle, L)
Vena Cava- brings in deoxygenated blood from the body
Blood passes from the heart to the lungs in the pulmonary artery
Oxygenated blood passed from lungs to heart in the pulmonary artery
Oxygenated blood pumped from the heart to the body in the aorta
Negatives of the single circulation of blood?
Blood looses a lot of pressure as it passed through the gills before reaching the organs
This means blood travels to the organs slowly so it cannot deliver a lot of oxygen
Job of Coronary arteries
Coronary arteries- to provide oxygen to the muscle cells of the heart
=> oxygen used in respiration to provide energy for the contraction
Where is the Pacemaker
(right atrium)- resting heart rate is controlled by the pacemaker
Features of a Arteries
Away from heart to organs (oxygenated blood)
Very high pressure blood
Very thick muscular walls- can withstand the high pressure
Elastic fibres stretch when blood passed, then recoils in between surges (keeps blood moving)
Features of Capillaries
Substance exchange
=> glucose and oxygen to cells => Co2 back into blood
Very thin walls- diffusion pathway is short - diffuse rapidly
Features of Veins
Thin wall- blood pressure is low so it doesn’t need to be thick
Valves- prevent backflow
What is coronary heart disease
Coronary arteries- provide oxygen to muscle cells in heart
=> then used for respiration to provide every for contraction
In disease- layers of fatty material build up inside the arteries
=> they narrow reducing blood flow
=> lack of oxygen to heart
=> heart attack (starved of oxygen)
Ways to fix this (2 methods) and adv and dis
Statins- drugs which reduce the levels of cholesterol in blood
=> slows rate that fatty materials build up in arteries
Advantages
Reduce risk of heart disease
Disadvantage
Unwanted liver problems
Treated with stents- tube inserted to artery to keep it open
Advantages
Can allow blood to flow normally through artery
Disadvantages
Will not prevent other regions of coronary artery from flowing
=> does not treat underlying causes of the disease
Problem with Valves (adv and dis of animal and mechanical)
When valves do not fully open- heart has to pump extra hard to get the blood through
=> causes heart to enlarge
=> leaky valves- patient is weak and tired
Adv of Mechanical
Can last a lifetime
Dis of Mechanical
Increase risk of blood clots
Have to take anti- clotting drugs
Adv of Animal
Patient does not need to take drugs
Dis of Animal
Needs to be replaced every 12-15 years
Artificial Heart Problems (dis of Artificial and donated)
Where heart cannot pump enough blood around body
=> heart failure
=> given donated heart
Disadvantage of Donated Heart
Not enough hearts to donate to everyone
Patient must take drugs to stop heart being rejected
Disadvantage of Artificial Heart
Increase risk of blood clotting
Not long-term solution
Artificial Pacemakers and their benefits
If natural pacemaker stops it can beat too fast or too slow
=> too slow = not enough oxygen
=> too fast = blood not pumped properly
They send electrical signals to correct irregularities in the heart rhythm
Advantages
Very light- 20g-50g
Features and Functions of:
Epidermal tissues Palisade mesophyll Spongy mesophyll Xylem Phloem Meristem tissue
Covered with waxy cuticle
Help to reduce water loss by evaporation
=> waxy cuticle prevents water from moving out
Lots of chloroplasts
Photosynthesis can happen rapidly
Positioned at top of leaf to receive a lot of light
Lots of air spaces
Allows gases to diffuse in and out of cell
Made up of dead cells creating tube Strengthened by Lignin Allows for movement of water and mineral ions => transpiration (single direction) Lignin makes it strong
Made of: Elongated cells with holes with small holes (pores) that join them together
=> end of walls are sieve plates
Cell sap can move from one phloem cell to the next through pores in the end walls.
Food (amino acids and sugar) can move up and down
Osmosis for water to go into roots
Then Transports food from sources to the sieve plates
=> active transport required
Translocation
Able to differentiate
Growth and repair
What is translocation?
Translocation is the movement of food substances made in the leaves up or down the phloem, for immediate use or storage
What is transpiration?
Transpiration is the loss of water vapour from leaves and stems of plant
=> it is consequence of gaseous exchange as stomata are open
=>ie for respiration , stored as starch
