Question

photosynthesis and respiration model
essential question: what is the relationship between photosynthesis and respiration?
scientific modelling is an activity that aims to make the world easier to understand. there are many types of models, some are mathematical, and some are graphical models that help us visualize the subject. the graphic below is a model that attempts to show the interdependence of two cellular processes: respiration and photosynthesis. your goal is to examine the model, focus on the key details to answer the essential question.
photosynthesis: plants only
6co₂ + 6h₂o + energy → c₆h₁₂o₆ + 6o₂
sunlight (energy)
chloroplast
co₂ + h₂o
glucose
mitochondrion
o₂
respiration: plants and animals
c₆h₁₂o₆ + 6o₂ → 6co₂ + 6h₂o + energy
energy (atp)
o₂
examine details
n what cell organelle does photosynthesis occur?
in what cell organelle does cellular respiration occur?
what are the three things needed for photosynthesis? highlight them on the diagram in green.
what are the two products of photosynthesis? highlight yellow.
what are the two things needed for cellular respiration? highlight blue.
what are the three products of cellular respiration? highlight purple.
what things are recycled (used over and over again) during photosynthesis and respiration?
ii. apply (what you already know)

1. sketch a model of a typical plant cell and identify the mitochondria and chloroplasts.
2. what will happen to plants that are kept in the dark?
3. what will happen if you forget to water your plants?
4. what happens to animals that are deprived of oxygen?

Answer:

To answer the questions related to the Photosynthesis and Respiration Model, we analyze each part based on biological concepts:

1. In what cell organelle does photosynthesis occur?

Photosynthesis occurs in the chloroplast (an organelle with chlorophyll that captures light energy).

2. In what cell organelle does cellular respiration occur?

Cellular respiration (aerobic) occurs in the mitochondrion (where glucose is broken down to release energy).

3. What are the three things needed for photosynthesis?

From the equation \( 6\text{CO}_2 + 6\text{H}_2\text{O} + \text{energy}
ightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2 \), the three inputs are:

• Carbon dioxide (\(\text{CO}_2\))
• Water (\(\text{H}_2\text{O}\))
• Light energy (from sunlight)

4. What are the two products of photosynthesis?

From the photosynthesis equation, the products are:

• Glucose (\(\text{C}_6\text{H}_{12}\text{O}_6\))
• Oxygen (\(\text{O}_2\))

5. What are the two things needed for cellular respiration?

From the respiration equation \( \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2
ightarrow 6\text{CO}_2 + 6\text{H}_2\text{O} + \text{energy} \), the inputs are:

• Glucose (\(\text{C}_6\text{H}_{12}\text{O}_6\))
• Oxygen (\(\text{O}_2\))

6. What are the three products of cellular respiration?

From the respiration equation, the products are:

• Carbon dioxide (\(\text{CO}_2\))
• Water (\(\text{H}_2\text{O}\))
• Energy (in the form of ATP)

7. What things are recycled during photosynthesis and respiration?

• Carbon dioxide (\(\text{CO}_2\)): Produced in respiration, used in photosynthesis.
• Water (\(\text{H}_2\text{O}\)): Produced in respiration, used in photosynthesis.
• Oxygen (\(\text{O}_2\)): Produced in photosynthesis, used in respiration.
• Glucose: Produced in photosynthesis, used in respiration (recycled as a source of energy).

8. Sketch a model of a typical plant cell and identify the mitochondria and chloroplasts.

A typical plant cell includes:

• Cell wall (outer rigid layer), cell membrane (inner to cell wall), cytoplasm (gel-like matrix), nucleus (control center), vacuole (stores water), chloroplasts (oval-shaped with chlorophyll, for photosynthesis), and mitochondria (bean-shaped with inner folds, for respiration). Label chloroplasts (green) and mitochondria (often brown/red) in the sketch.

9. What will happen to plants that are kept in the dark?

Photosynthesis requires light energy. In the dark, plants cannot perform photosynthesis (so no glucose production). They will rely on stored glucose for respiration, but over time, energy reserves deplete, growth stops, and the plant may die (due to lack of energy and food).

10. What will happen if you forget to water your plants?

Water is a key reactant in photosynthesis and is needed for turgor pressure (cell rigidity) and nutrient transport. Without water:

• Photosynthesis slows/stops (no \(\text{H}_2\text{O}\) for glucose production).
• Cells lose turgor (plant wilts).
• Nutrient uptake (via water) stops, leading to nutrient deficiency.
• Eventually, the plant dies from energy/food shortage and dehydration.

11. What happens to animals that are deprived of oxygen?

Animals use oxygen for aerobic respiration (to break down glucose and release energy). Without oxygen:

• Aerobic respiration stops; cells switch to less efficient anaerobic respiration (produces lactic acid in animals).
• Energy production drops drastically, causing fatigue, organ failure, and eventually death (due to insufficient ATP for vital processes).

Relationship Between Photosynthesis and Respiration:

• Photosynthesis (in chloroplasts) produces glucose and oxygen, using \(\text{CO}_2\), \(\text{H}_2\text{O}\), and light.
• Respiration (in mitochondria) uses glucose and oxygen to produce \(\text{CO}_2\), \(\text{H}_2\text{O}\), and energy (ATP).
• They are interdependent: Photosynthesis provides the glucose and oxygen needed for respiration, while respiration provides the \(\text{CO}_2\) and \(\text{H}_2\text{O}\) needed for photosynthesis. This creates a cycle of gas and energy flow between plants and animals (and within ecosystems).

For specific question answers (e.g., organelles, reactants/products), refer to the detailed breakdown above.