Bioenergetics Flashcards
What is the word equation for photosynthesis?
“Carbon dioxide + water → glucose + oxygen (light energy absorbed by chlorophyll).”
What is the balanced chemical equation for photosynthesis?
“6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂.”
Name three factors that limit photosynthesis.
“1. Light intensity 2. Carbon dioxide concentration 3. Temperature (optimum enzyme activity).”
How is a leaf adapted for photosynthesis?
“1. Broad (large surface area) 2. Thin (short diffusion path) 3. Chlorophyll in chloroplasts 4. Stomata for gas exchange.”
What is the role of chlorophyll in photosynthesis?
“Absorbs light energy from sun for photosynthesis
What happens to glucose produced in photosynthesis?
“1. Respired for energy 2. Stored as starch 3. Converted to cellulose (cell walls) 4. Used to make proteins with nitrates.”
What is the word equation for aerobic respiration?
“Glucose + oxygen → carbon dioxide + water (+ energy).”
What is the purpose of respiration?
“To release energy (ATP) for processes like growth, movement, and temperature regulation.”
What is anaerobic respiration in muscles?
“Glucose → lactic acid (+ small ATP yield). Occurs when oxygen is limited (e.g., intense exercise).”
What is oxygen debt?
Oxygen debt is the extra oxygen required after exercise to remove lactic acid and restore energy stores in muscles.
What is anaerobic respiration in yeast?
“Glucose → ethanol + carbon dioxide. Used in brewing/bread-making (fermentation).”
Compare aerobic and anaerobic respiration.
“Aerobic: uses oxygen. Anaerobic: no oxygen, produces lactic acid/ethanol.”
How does exercise affect heart and breathing rate?
“Increases to deliver more oxygen/glucose to muscles and remove CO₂/lactic acid.”
What is metabolism?
“Sum of all chemical reactions in the body, e.g., glucose → starch/glycogen, lipid synthesis, protein formation.”
Give two examples of metabolic reactions.
Respiration, photosynthesis, protein synthesis
Why do organisms need energy?
“1. Growth 2. Movement 3. Homeostasis (e.g., thermoregulation) 4. Active transport.”
What happens if a plant lacks nitrate ions?
“Stunted growth (needed for amino acids/proteins).”
What happens if a plant lacks magnesium ions?
If a plant lacks magnesium ions:
It can’t produce enough chlorophyll, leading to yellowing of leaves (chlorosis).
Photosynthesis is reduced, causing stunted growth and poor development.
The plant may also have reduced flowering and fruiting.
How does temperature affect photosynthesis?
“Increases rate up to optimum (enzyme activity), then denatures enzymes, reducing rate.”
How do greenhouses control limiting factors?
“1. Artificial light 2. Heating 3. CO₂ enrichment → maximises photosynthesis.”
What is a ‘limiting factor’?
“A variable that restricts the rate of a process (e.g., low CO₂ slows photosynthesis).”
How is energy transferred in ecosystems?
“Sun → producers (photosynthesis) → consumers (respiration) → heat loss at each trophic level.”
Why is respiration exothermic?
Releases energy as heat (e.g., mammals maintain body temperature).
