Chapter 5 Flashcards
What is photosynthesis?
Process by which light energy is harnessed to produce glucose
Photosynthesis is crucial for converting solar energy into chemical energy stored in glucose.
What is the overall equation for photosynthesis?
6CO2 + 6H2O → C6H12O6 + 6O2
This equation summarizes the reactants and products of the photosynthesis process.
Where does photosynthesis primarily occur in plants?
In the leaves
Leaves have a large surface area to volume ratio to maximize light absorption.
What is the purpose of the light-dependent reactions?
To generate high energy coenzymes such as NADPH and ATP
These coenzymes are essential for the next stage of photosynthesis.
What are the inputs for the light-dependent reactions?
12H2O, 12NADP+, 18ADP + Pi
Water is split to provide electrons and protons during this stage.
What are the outputs of the light-dependent reactions?
6O2, 12NADPH, 18ATP
Oxygen is released as a byproduct of water splitting.
What happens during the light-dependent reactions?
Sunlight excites an electron within chlorophyll, water is split, and coenzymes NADPH and ATP are produced
The splitting of water releases oxygen as a waste product.
What is the light-independent reaction also known as?
Calvin Cycle
This process does not require light and takes place in the stroma of chloroplasts.
What are the inputs for the light-independent reactions?
6CO2, 12NADPH, 18ATP
These inputs are used to synthesize glucose.
What are the outputs of the light-independent reactions?
6H2O, 1 glucose (C6H12O6), 18ADP + Pi, 12NADP+
Glucose serves as an energy source for the plant.
What role do mesophyll cells play in photosynthesis?
Contain large amounts of chloroplasts for photosynthesis
Mesophyll cells are the primary sites for light absorption.
What is Rubisco?
Key enzyme in light-independent stage of photosynthesis
Rubisco catalyzes the fixation of carbon dioxide.
What is the problem associated with Rubisco?
It can use O2 instead of CO2, leading to photorespiration
Photorespiration is wasteful and reduces plant efficiency.
What adaptations do C4 plants have?
Photosynthesis occurs in two different cell types: mesophyll and bundle sheath cells
This separation helps reduce photorespiration.
What is Kranz Anatomy?
The arrangement of vascular bundles in C4 plants
This structure is key for efficient carbon fixation.
What is the function of PEP carboxylase in C4 plants?
Combines CO2 with PEP to form a 4-carbon molecule
This process enhances carbon fixation efficiency.
What are CAM plants known for?
They fix CO2 at night to minimize water loss
This adaptation helps them survive in arid conditions.
What factors affect the rate of photosynthesis?
Light intensity, light color, temperature, pH, carbon dioxide, water, enzyme inhibition
Each factor can limit or enhance the photosynthesis rate.
What is the optimal temperature for Rubisco activity?
Approximately 25 degrees Celsius
At higher temperatures, Rubisco may denature or bind to O2 more frequently.
What is enzyme inhibition?
Reduces the rate of photosynthesis
Competitive reversible inhibitors can be overcome by increasing substrate concentration.
What is the role of CRISPR-Cas9 in agriculture?
To improve crop yields and efficiency
It allows for precise gene editing to enhance photosynthesis and reduce photorespiration.
What is one way CRISPR can improve crops?
By creating crops that bypass photorespiration
This mimics the efficiency of C4 and CAM plants.
What is one step in researching the appropriateness of using CRISPR?
Understanding the entire photosynthesis process of the crop
This involves studying the photorespiration pathway and identifying inefficiencies.
