KS4 Combined ScienceWorkbook
Bioenergetics
GlucoseOxygen Carbon dioxide PhotosynthesisEnergyChloroplastsChlorophyll
EndothermicExothermicRateRespirationAerobicAnaerobicOxygen debt
FatigueLactic acidMetabolism Fermentation
Key word bank:
2
Glossary
Key word Definition
Aerobic respiration
Mitochondria
Anaerobic respiration
Glucose
Lactic acid
Fermentation
Oxygen debt
Urea
Photosynthesis
Limiting factors
Light intensity
Chloroplast
Chlorophyll
Starch
Cellulose
5
Use the clues on the following page to complete the crossword
Crossword clues
Photosynthesis
Respiration
Fermentation
Past Exam Questions
KS4 Combined ScienceWorkbook
Bioenergetics
ANSWERS
In any order: • Concentration of carbon dioxide • Light intensity • Temperature
Experiment 1 and 2 are illustrating the effect of temperature on the rate of photosynthesis. As the temperature increases, so does the rate of photosynthesis. Experiment 3 has an increased concentration of carbon dioxide and a faster rate of photosynthesis than experiments 1 and 2. Initially, as the light intensity increased, so did the rate of photosynthesis. However, the lines levelling off illustrate that light is no longer a factor.
light intensity/distance of lamp from pondweed.
number of bubbles produced per minute
same amount of pondweed; same amount of time; same lamp (wattage).
Oxygen
As the lamp was moved further away from the beaker, the number of bubbles produced decreased. For the second mark, pupils should give examples using data from the table.
10 20 30 40 5000
10
20x
x
x
xx
Distance from lamp to beaker (cm)
Num
ber o
f bub
bles
per
min
ute
Respiration
No. Respiration is a process that requires oxygen to produce energy. (Accept reference to breathing simply being ventilation.
A reaction which transfers energy to the environment
oxygen water
Metabolism describes all the chemical reactions in an organism
Fermentation
Anaerobic respiration, because no oxygen is required
Bread, wine, beer
Past Exam Questions
x
• description of how the apparatus would be used• reference to control intensity of light / brightness• use of ruler to measure distance of light from beaker / pondweed• reference to varying colour of light or use of different filters• plant releases gas / oxygen• measure number of bubbles / volume of gas produced• same length of time• reference to control of temperature• reference to control / supply of carbon dioxide in water• do repeats and calculate a mean
rate does not increase further if light intensity increased beyond 20allow graph levels off after 20
• temperature• carbon dioxide (concentration)• amount of chlorophyllallow number of chloroplasts
to transfer / provide / give release energyor production of ATP / adenosine triphosphate (molecules)accept to give heat
C6H12O6 + 6O2 → 6CO2 + 6H2O
glucose
large surfacethin (surface)moist (surface)(with a good) blood supply
carbon dioxide
anaerobic (respiration)
any three from
• in mitochondria
• glucose decomposes / breaks down / reactsor glucose → lactic acid for (2) marks
• to give lactic acidor breathing hardor lactic acid → CO2 + water
• causing pain(leaving an) oxygen debt(quick) source of energy
• (but) less efficient than aerobic respirationaccept less efficient than with oxygen
insufficient / no oxygen available
for (just) aerobic respiration
orrespires anaerobically
(to) stop them falling in the solution
or
to stop them drowning (in the solution)
• water droplet moves towards the maggots / boiling tube
Explanation:• the oxygen in the boiling tube is used up in respiration• (and) the carbon dioxide released from respiration is absorbed by solution A• which causes a pressure difference• so air is drawn into the tube• bringing the water droplet with it.
x axis: Temperature in °Cboth needed for the mark
y axis: Rate of respiration in units
Temperature in °C
Rat
e of
resp
iratio
n in
uni
ts
repeat the experiment at 30 °C
10.5allow range 10.4–10.8
