Bio Paper 2 Flashcards
Why does incomplete combination occur? 
because it’s not enough oxygen for complete combustion 
What is the equation for photosynthesis? (symbol)
6CO2 + 6H2O -> C6H12O6 + 6O2
What are the control variables in a photosynthesis practical?
Temperature, concentration of sodium hydrogencarbonate, type of weed and mass of weed
Describe how you would test to see how light intensity affects the rate of photosynthesis? (6 marks)
- put pond weed and sodium hydrogen carbonate in a beaker with a bung
- connect gas syringe onto beaker
- put light source a set distants away and use a stopwatch to time 10 minutes
- gas syringe will show am out of oxygen produced
- oxygen produced / time = cm3/min
- control = temp / conc of sodium / weed / mass of weed
- repeat at different distances to compare the affect of light intensity
Describe the difference between the phloem and the xylem (6 marks)
Phloem:
- living
- transfers food
- process = translocation
- requires energy
- has end walls
Xylem:
- dead
- transports water and minerals
- only transfers up
- process = transpiration
- no end walls
How does transpiration occurs (3 marks)
- Evaporation ( diffusion out stomata)
- xylem
- ## absorption
What increases transportation?
- increase in light intensity
- increase in temperature
- increase in air flow
How would you measure rate of transportation (6 marks)
- use a potometer with a plant at the top and a beaker of water at the bottom
- use a ruler and put it at a air bubble
- start a stop watch for 10 minutes
- record distance the air bubble traveled
- distance / time = mm/min
- repeat by turning tap on reservoir of water to put air bubble back
What diffuses out of stomata?
CO2, H2O and O2
What do guard cells do?
Change shape to open and close stomata (when turgid it’s open - when flaccid it closed)
What are the layers of a leaf? (4 marks)
- upper epidermis (waxy)
- palisade mesophyll tissue
- spongy mesophyll tissue
- lower epidermis
What are all the adaptations of leaves (6 marks)
- large surface area
- palisade layer near top for light
- upper epidermis is transparent so light can get to palisade layer
- xylem and phloem for water and to transport glucose as slucose
- waxy layer reduces water loss
- sponge mesophyll contains air gaps to increase rate of diffusion
- lower epidermis has lots of stomata to let CO2 diffuse in
What do select weed killers do?
- they are developed from auxins
- affect broad leaves
- disrupts growth pattern-> killing it
Why would you grow from cutting root powder?
- contains auxins
- produces rapid clones
How and why do you control flowering for fruit formation? (3 marks)
- gibberlellins stimulate seed germination and stem cells
- plants can flower earlier in a hasher condition
- this reduces flowers formation
- improving fruit quality
How do you make seedless fruit?(1 mark)
Add gibberelins to unpollinated flower and only fruit will grow
Why and how do we control ripening of fruit? (2 marks)
- Allows fruit to travel before ripe so there is less damage
- ethene is added on the way to store
Why and how do we control seed germination? (2 marks)
- to make seeds germinate any time
- helping batches grow all together
- use gibberellins
What does the pituitary gland do? (3 marks)
- produces many hormones
- regulates body conditions
- directs other glands to release hormones
What does the thyroid gland do? (2 marks)
- produces thyroxine
- regulates (metabolism/heart rate/temperature)
What does the pancreas do? (2 marks)
- produces insulin
- regulates blood glucose
Describe the endocrine glands (4 marks)
- the do constant adjustments to the body
- slow action
- long lasting
- works in a generally area of body
- travels through the blood
Describe how adrenaline works (6 marks)
- adrenaline binds to receptors in heart
- causes muscles to contract with more force (increasing blood pressure)
- increasing the blood flow so muscle can reserve O2 and glucose for respiration
- adrenaline binds to liver causing break down of glycogen
- this releases glucose increasing blood glucose levels
- this means more glucose can get to cells
How does thyroxine regulate metabolism? (4 marks)
- when blood thyroxine levels are too low
- hypothalamus releases TRH that stimulates the pituitary gland to release TSH
- This stimulates thyroid gland to release thyroxine until levels are too high
- TRH from hypothalamus is inhibited with reduces TSH so blood thyroxine levels fall
In the menstrual cycle what does FSH do? (4 marks)
- cause egg to mature
- follical stimulating hormone
- is realised from pituitary gland
- stimulates production of oestrogen
What does oestrogen do in the menstrual cycle? (2 marks)
- Thicken the uterus lining
- stimulates a rapid production of LH
What does LH do in the menstrual cycle? (3 marks)
- produced by pituitary gland
- releases egg
- stimulates remains of follide to develop a corpus luteum
What does the corpus luteum do in the menstrual cycle? (3 marks)
- produces progesterone
- which maintains uterus lining
- also stops production of FSH and LH
What happened when progesterone falls and there’s a low oestrogen level? (2 marks)
- lining breaks down
- FSH is released and cycle starts again
What does clomifene therapy do? (2 marks)
- if you can’t reproduce naturally
- produces FSH and LH
- alows egg to be produced
What is IVF used for (1 mark)
- forming embryo in a lab for someone that can’t reproduce
What does progesterone do in the mini pill or injection? (2 marks)
- build cerrical mucus
- acts as a barrier
That does oestrogen do in the combined pill? (1 mark)
- inhibits FSH stopping egg maturing
What happens if blood glucose levels are too high? ( 4 marks )
- pancreas releases insulin into blood
- insulin alows glucose to be removed from blood
- by storing glucose in liver/ muscles as glycogen
- decreases blood glucose levels
What happened when blood glucose is too low? (3 marks)
- pancreas release glucagon
- glucagon breaks down glycogen into glucose
- increasing blood glucose levels
What is the thermoregulatory centre?
Restores the detect body temperature in the brain
What does thermoregulation do and why? (2 marks)
- control body temperature
- keeps body at 37 degrees for enzyme optimum temperature
What happens when your body gets too hot? (4 marks)
- erector muscles relax so hairs go flat
- sweat glands release sweat through pores
- this uses evaporation to transfer energy in sweat into the environment
- blood vessels get closer to skin for vasodilation
What happens when your body gets too cold? (4 marks)
- erector muscles contract so hair stands insulating the body
- no sweat
- blood vessels close to skin constrict for vasoconstriction
- shivering increases respiration rate
What is the role of the kidney? (3 marks)
- removes urea from the blood
- adjust water level
-so cells don’t burst due to osmosis
Explain what a bowman’s capsule does? ( 4 marks )
- ultra filtration
- glucose, water, ions and urea are forced into the capsule
- useful substances are are re absorbed like glucose + needed ions + needed water ( depending on ADH )
- what isn’t absorbed leaves though collecting duct into bladder as urine
How are nephrons adapted? (2 marks)
- high pressure glomerulus so small molecules can easily diffuse through
- membrane so big cells can’t get through
What are the 4 main parts of a nephron?
- glomerulus
- bowman’s capsule
- loops of Henley
- collecting duct
What happens then there is a gain of water in the blood? (3 marks)
- brain detects gain
- pituitary gland releases less ADH
- causes kidney to absorb less water back into the blood
What happens when there is a Loss of water in the blood? (3marks)
- brain detects loss
- pituitary gland releases more ADH
- causes kidney to absorb more water back into the blood
How does a dialysis machine work?(3 marks)
- acts like a kidney outside of body that’s has to be do regularly
- it has the same concentration as glucose so it doesn’t get removed
- barrier is permeable so ions can pass though but proteins don’t
What’s the issues with transplants?( 2 marks)
- donor must be a close match of tissue or it will be rejected
- drugs must be taken to weaken immune systems so it doesn’t attack organ
What/Why do we have alveoli and what’s its adaptations? (5 marks)
- lungs hand to remove CO2 from the blood
- they are lots of air sacks in the lungs
- they moist lining for dissolving gas
- they maintain a concentration gradient
- thin walls to minimise distance
- enormous surface area
Whats the difference between lymphocytes and phagocytes? (2 marks)
- phagocytes -> engulf unwanted organisms
- lymphocytes -> makes antibodies to trap pathogens
That’s the difference between platelets and plasma in the blood? (4 marks)
- platelets -> no nucleus
- help to clot blood wounds
- plasma -> liquid that carries things around blood (hormones/CO/blood cells/hormones)
- takes urea from liver to kidneys
- takes CO2 from organs to lungs
What are the different between the Arteries and the veins? (6 marks)
Arteries
- strong/elastic/thick
- away from heart
- layers of muscle, “lumen” = hole
Veins
- not as thick
- towards heart
- large lumen, valve = keep blood in same direction
What are the 2 entrances and 2 exits to the heart and where do they go/come from? (8 marks)
- vena cava
- brings deoxygenated blood into the right atrium
- pulmonary artery
- takes deoxygenated blood to the lungs
- pulmonary vein
- brings oxygenated blood to the left atrium
- aorta
- takes oxygenated blood to the rest of the body
What blood system does humans body have? (1 marks)
Double circulatory system
How to set up a respiration practical? (4 marks)
- add soda lime granules to test tubes
- Wool is put under woodlice and same mass glass needs go in the other tube as a control
- Respirator is set up
- Syringe is used to set fluid in manometer containing coloured fluid
How would you work out the affect of temperature on rate of respiration with woodlice? (6 marks)
- set up all the equipment and temperature
1. Use syringe to set fluid in manometer containing coloured fluid
2. Leave for time in water bath at 15 degrees
3. You’ll see a decrease in volume in the wood lice test tube
4. This reduces pressure so coloured liquid will move towards the woodlice
5. Distance moved by liquid is measured to calculate volume of oxygen used per minute
6. Repeat at different temperatures to see the affect
What is a quadrate used for? (1)
- to find estimation of the population of an organism in an area
What is a belt transect used for? (1)
- to measure how a population is affected by an abiotic factor
How would you use a belt transect to measure how a river affects an organism? (3)
- us a tape measure so you can put down a quadrate at regular intervals
- at each quadrate count amount of that organism and the difference from the river
- repeat at the same distances you have down before to find a mean for a more accurate result
What is a trophic level? (1)
- the different levels of the food chain/ energy transfers
How can fertilisers cause eutrophication? (5)
- Fertilisers enter water adding excess nitrates
- This causes algae to grow faster blocking out the light
- Plants then can’t photosynthesises so they die and decompose
- Microorganisms feed on decomposing plants increasing amount of them -> more oxygen is used up
- Organisms need oxygen to survive so fish die
What is the problems with fish farming? (4)
- food use to feed fish produces waste can leak into open water causing eutrophication
- parasites breed there and can get out -> infecting the wild
- predators are attracted to net and can get trapped and die
- farmed fish can escape and cause problems for native species
What are non-indigenous species and what is the problem with them? (2)
- not naturally in that environment
- they will compete for resources reducing the biodiversity
In the Carbon cycle, what is the one thing that takes carbon out of the air? (1)
- photosynthesis
In the carbon cycle, what puts carbon in the air? (4)
- respiration in plants
- respiration in animals after they eat the plant
- plants and animals decaying
- plants and animal Turing into fossils fuels that turn to CO2 through combustion
What percentage of the atmosphere is nitrogen? (1)
- 78%
In the nitrogen cycle, what removes nitrogen from the air? (2)
- nitrogen fixing bacteria that turns it into nitrates in the soil or plants
- lighting that does the same
In the nitrogen cycle, how does nitrogen get back into the air? (3)
- decomposers turn dead things into ammonia
- nitrifying bacteria turns ammonia into nitrates
- denitrifying bacteria puts nitrates into the air (that have either been put there through nitrifying or nitrogen fixing bacteria)
What species shows there is NO water pollution and why AND LOTS of water pollution and why? (4)
GOOD-
- fresh water shrimp / stonefly larvae
- as they are sensitive to dissolved oxygen
BAD-
- bloodworms / sludge worms
- as they live in low oxygen levels
Explain How do you increase nitrates in soil? (4)
- crop rotation
- different crops grow each year on a cycle (so on year you can have nitrogen fixing crops to increase nitrates in soil)
- fertilisers (animal manure / compost)
- recycled nutrients that returns to soil through decomposition
What species shows there is NO air pollution and why AND moderate air pollution and why? (4)
GOOD-
- lichens (bushy) / black spots fungus
- sensitive to SO2
BAD-
- lichens (crusty)
- less sensitive to SO2
What determines how polluted the air is? (1)
- concentration of SO2
What are the limitations of indicator species? (1)
- doesn’t show percentage of SO2
What are the advantages of indicator species? (1)
- cheap and quick way to test pollution
- if you count in different areas you can compare amount
Other than indicator species, how else would you measure SO2?
- dissolved oxygen metre
- electronic metres
What causes something to decompose?(1)
- microorganisms
Explained What can increase the rate of decomposition? (6)
- increasing temperature
- speeds up enzymes (until denatured)
- increasing water concentration
- organisms need water to survive
- increasing oxygen levels
- microorganisms need O2 for respiration(most the time)
Explain how you can preserve food? (6)
- fridge / freezer
- lowering temperature slows down rate of decomposition
- air tight can
- stop microorganisms getting in / pressure is too high to survive
- drying / adding salt or sugar
- removes water that microorganisms need to survive
What is the equation for light intensity? (1)
1/(distance^2)
What is the equation for BMI and waist to hip ratio? (2)
BMI = Kg/m^2
W:H = waist circumference/hip circumference
What is the equation for the rate of diffusion? (1)
(Surface area x concentration difference)
—————————————-
Thinkness
What is the equation for cardiac output? (1)
Heart rate x stroke volume
What is the word equation for anaerobic respiration in plants AND animals?
Animals = glucose -> lactic acid
Plants = glucose-> ethanol + carbon dioxide
What is the symbol equation for aerobic respiration? (1)
C6H12O6 + 6O2 -> 6CO2 + 6H2O
What is then equation for efficiency in terms of tropic levels? (1)
(energy transfer to next level)
———————————————X100
Energy available at previous level
