bioenergetics Flashcards
what is the word equation for photosynthesis?
carbon dioxide + water (with light) —> glucose + oxygen
what is the symbol equation for photosynthesis?
6CO2 + 6H2O —> C6H12O6 + 6O2
what is glucose used for?
- respiration
- cellulose
- amino acids
- stored as oils/fats
- stored as starch
what are limiting factors?
An environmental factor which can restrict the rate of a process happening
what are the limiting factors of photosynthesis?
- light
- carbon dioxide concentration
- temperature
where does photosynthesis take place?
Within chloroplasts in leaf palisade cells. they contain chlorophyll, a pigment which absorbs light energy.
is photosynthesis endothermic or exothermic?
Endothermic, energy is transferred from the environment to the chloroplasts by light.
Give an example of a leaf adaptation to maximise photosynthesis:
1) broad leaves - maximise surface area
2) thin leaves - short diffusion distance
3) chlorophyll present - trap light energy
4) veins - transport water to leaves via xylem, remove photosynthesis products via phloem
5) air spaces - allow CO2 to enter and O2 to leave
What law describes the relationship between the distance of a light source from a plant and light intensity?
inverse square law
I = k / d^2
What is the process that occurs in plants and algae to produce glucose and oxygen?
Photosynthesis
How does carbon dioxide enter the leaves of plants?
By diffusion
How does water enter the roots of plants?
By osmosis
Why is photosynthesis described as an endothermic reaction?
Because energy is transferred from the surroundings to chloroplasts by light
How does temperature affect the rate of photosynthesis?
As temperature increases, the rate of photosynthesis increases until enzymes denature
How can knowledge of limiting factors help greenhouse growers?
- Maintain optimal conditions for photosynthesis
- Maximize crop yield
- Maintain profits
What is the relationship between light intensity and the rate of photosynthesis at different temperatures?
Higher temperatures and increased carbon dioxide concentration can lead to a higher maximum rate of photosynthesis
What is the inverse square law in relation to light intensity?
There is an inverse relationship between distance and light intensity - as the distance increases, light intensity decreases.
What type of reaction is respiration?
Exothermic
What are the two types of respiration?
Aerobic and anaerobic respiration
What is the main waste product of aerobic respiration?
Carbon dioxide and water
What is the equation for aerobic respiration?
Glucose + Oxygen → Carbon Dioxide + Water
What is produced during anaerobic respiration in animal cells, and what does it cause?
Lactic acid - it causes muscle fatigue (feels like cramps) and an oxygen debt
Aerobic respiration releases more energy than anaerobic respiration.
What is the difference in energy release between aerobic and anaerobic respiration?
What is fermentation in yeast cells?
It is anaerobic respiration that produces ethanol and carbon dioxide.
What is oxygen debt?
It is the amount of extra oxygen needed after exercise to remove lactic acid.
What is metabolism?
The sum of all the reactions in a cell or the body.
What is one example of metabolism in plants?
The conversion of glucose to starch.
What happens to excess amino acids in the body?
They are broken down into urea for excretion.
What is glycogen used for in animals?
It is used for storage of glucose.
What are the key differences between aerobic and anaerobic respiration?
Aerobic respiration:
- Uses oxygen
- Produces carbon
dioxide and water
- Releases more
energy
Anaerobic respiration:
- Does not use
oxygen
- Produces lactic acid
(in animals) or
ethanol and carbon
dioxide (in yeast)
- Releases less energy
What are the effects of exercise on respiration and metabolism?
- Increased breathing rate for more oxygen intake
- Increased heart rate for more oxygenated blood supply
- Anaerobic respiration occurs if oxygen is insufficient, leading to lactic acid buildup
- Oxygen debt occurs, requiring extra oxygen post-exercise to remove lactic acid
