Photosynthesis is a reaction where light energy is used to split water molecules through photolysis to combine hydrogen with carbon dioxide to produce glucose
Oxygen is a waste product of photosynthesis and is released into the atmosphere
The rate of photosynthesis is determined by carbon dioxide concentration, light intensity, and temperature
Chloroplast is the site of photosynthesis and is adapted with stacks of thylakoid membranes called grana containing chlorophyll and stroma containing enzymes for the light-independent stage
Two stages of photosynthesis:
Light-dependent reaction: electrons are excited by chlorophyll in thylakoid membranes, generating ATP and reduced NADP
Light-independent reaction (Calvin cycle): uses ATP and reduced NADP to produce glucose
Factors affecting photosynthesis:
Light intensity
CO2 concentration
Temperature
Respiration:
Aerobic respiration: releases carbon dioxide and reunites hydrogen with oxygen to produce energy
Anaerobic respiration: occurs without oxygen
Glycolysis is the first step, producing pyruvate, NADH, and ATP
Link reaction: converts pyruvate to acetyl, reducing NAD to NADH and producing CO2
Krebs cycle: oxidises glucose to produce CO2, ATP, reduced NAD, and reduced FAD
Oxidative phosphorylation:
ATP synthesis in the electron transport chain in mitochondria
Hydrogen ions and electrons carried by coenzymes to generate ATP
Oxygen acts as the final electron acceptor
Respiratory substrates include carbohydrates, lipids, and proteins
Respiratory quotient (RQ) can determine the respiratory substrate being used
Different RQ values for carbohydrates, lipids, and proteins
Anaerobic respiration:
ATP production continues through glycolysis
In mammals, pyruvate is converted to lactate
Yeast and plants use alcoholic fermentation to enable glycolysis to continue