B4, Bioenergetics Flashcards
(23 cards)
Word equation for photosynthesis
Balanced symbol equation for photosynthesis
Carbon Dioxide + Water -> Glucose + Oxygen
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
Choose correct one/fill in:
Photosynthesis is an endothermic/exothermic reaction, it requires ________ energy to occur
Endothermic, light
Where does photosynthesis occur?
Chloroplasts of palisade cells
3 limiting factors of photosynthesis
Light intensity, Carbon dioxide concentration, Temperature
Explain how light intensity is a limiting factor of photosynthesis
Photosynthesis is an endothermic reaction, it requires light energy to occur.
When light intensity is low, a plant does not receive enough energy to fuel the reaction at higher rates, even if other factors are at their optimal points.
Explain how carbon dioxide concentration is a limiting factor of photosynthesis
Carbon dioxide is a reactant in photosynthesis.
When the carbon dioxide concentration is low, carbon dioxide diffuses into the plant at a slower rate.
This means that the plant’s supply of carbon dioxide is not plentiful enough for photosynthesis to occur at higher rates, even if other factors are at their optimal points.
Explain how temperature is a limiting factor of photosynthesis
The chemical reaction between water and carbon dioxide in photosynthesis is controlled by enzymes.
Enzymes assist in chemical reactions by forming complimentary fits with substrates in successful molecular collisions.
When the temperature is high, the kinetic energy store of enzymes increase. They move quicker and have more successful collisions, increasing the rate of photosynthesis
However, when the temperature increases past the optimal point, enzymes denature. This occurs because the increased kinetic store of enzymes cause them to collide with greater force, the impact of which causes them to denature
When an enzyme is denatured, it cannot form complimentary fits with the substrate, there fore photosynthesis occurs at a lesser rate.
What is the inverse square law?
Formula:
1 Light Intensity ∝ ------------------------------
(Distance form light)²
List 5 usages of glucose in plants
1) Converted to starch as a form of storage
2) Used in cellular aerobic respiration
3) Used to produce cellulose
4) Used to produce proteins (amino acids)
5) Used to produce lipids
Why is glucose converted to starch in plants?
Glucose is soluble, it can affect osmosis in plants. When converted to starch, osmosis can remain unaffected.
Starch is stored in the roots of plants to be used when photosynthesis is insufficient.
Glucose is used to produce cellulose. What is the purpose of cellulose?
Strengthens cell walls, which provides structural support for rapidly growing plants.
How is glucose used to produce proteins?
Glucose is combined with minerals, for example nitrates to form amino acids. These in turn synthesise proteins.
Word equation for aerobic respiration
Balanced symbol equation for aerobic respiration
Glucose + Oxygen → Carbon Dioxide + Water
C₆H₁₂O₆ + 6O₂→ 6CO₂ + 6H₂O
Word equation for anaerobic respiration
Balanced symbol equation for anaerobic respiration
Glucose → Lactic Acid
C₆H₁₂O₆ →2C₃H₆O₃
Choose one/fill in:
Aerobic respiration is an endothermic/exothermic reaction, it ____________ glucose and releases energy in the form of ATP. This reaction occurs in the ____________.
Exothermic, oxidises, mitochondria
Name 4 differences between aerobic and anaerobic respiration
Aerobic respiration uses oxygen as a reactant, anaerobic respiration occurs when oxygen is insufficient.
Aerobic respiration is more efficient compared to anaerobic respiration.
Aerobic respiration is slower than anaerobic respiration.
Aerobic respiration occurs in the mitochondria, anaerobic respiration occurs in the cytoplasm.
Name 4 reasons why organisms may require energy released in respiration
- Muscle contractions (movement)
- Warmth (energy transferred to thermal store to regulate temperature)
- Chemical reactions such as protein and lipid synthesis or DNA replication
- Moving minerals via active transport
Lactic acid is a toxin to muscles, a buildup of it..
prevents muscle contraction and causes muscle fatigue
What is an oxygen debt?
The extra oxygen a body needs after exercise to recover and return to a resting state
How does the body get rid of lactic acid?
Lactic acid diffuses into the bloodstream. It is brought to the liver, where:
a) lactic acid is oxidised
b) lactic acid is converted to glucose
These processes require oxygen
Define ‘Metabolism’
Sum of ALL chemical reactions happening in a cell or organism, where molecules are beingmade/boken down.
Name 6 functions of the liver
1) Takes in glucose and converts it to glycogen. Breaks down glycogen into glucose.
2) Synthesises bile
3) Produces some vitamins
4) Stores glycogen
5) Oxidises lactic acid
6) Converts lactic acid to glucose
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