Printable biology worksheet designed to test students' understanding of the photosynthesis process through fill-in-the-blank questions.
Fill in the blanks worksheet about photosynthesis stages and processes.
PNG
1000×1415
118.5 KB
Free · Personal Use
Quality Assured by Worksheets Library Team
Reviewed for educational accuracy and age-appropriateness
ID: #503683
⭐
Show Answer Key & Explanations
Step-by-step solution for: Photosynthesis | Fill In The Blanks Worksheet
▼
Show Answer Key & Explanations
Step-by-step solution for: Photosynthesis | Fill In The Blanks Worksheet
Here’s the completed “Fill in the Blanks” worksheet on photosynthesis, with clear explanations for each answer:
---
1) _Light reactions_ and _Calvin Cycle_ are the two stages of photosynthesis.
✔ *Explanation:* Photosynthesis occurs in two main phases: the light-dependent reactions (which require sunlight to produce ATP and NADPH) and the Calvin Cycle (light-independent reactions that use ATP and NADPH to make glucose).
---
2) _Chloroplast_ is the site of photosynthesis in plants.
✔ *Explanation:* Chloroplasts are specialized organelles in plant cells containing chlorophyll and the machinery needed to convert light energy into chemical energy.
---
3) Calvin-Benson Cycle is also called a _dark reaction_ or _light-independent reaction_.
✔ *Explanation:* Although it doesn’t directly need light, it depends on products from the light reactions (ATP and NADPH). It’s often called the “dark reaction” because it can occur without direct light — but not without the products of light reactions.
---
4) Light reactions take place in the _thylakoid membrane_.
✔ *Explanation:* The thylakoid membranes inside chloroplasts contain chlorophyll and electron transport chains where light energy is converted into chemical energy (ATP and NADPH).
---
5) A _granum_ is a stack of thylakoids.
✔ *Explanation:* Thylakoids are disk-like sacs; when stacked together, they form structures called grana (singular: granum), which increase surface area for light absorption.
---
6) Stroma is a _fluid-filled space_ surrounding the thylakoids.
✔ *Explanation:* The stroma is the gel-like substance inside the chloroplast, outside the thylakoids. This is where the Calvin Cycle occurs.
---
7) The Calvin Cycle takes place in the _stroma_.
✔ *Explanation:* As mentioned above, the stroma contains enzymes needed to fix carbon dioxide into sugar using ATP and NADPH.
---
8) _Glucose_ and _oxygen_ are produced as a result of photosynthesis.
✔ *Explanation:* The overall equation is: 6CO₂ + 6H₂O + light → C₆H₁₂O₆ (glucose) + 6O₂. Glucose stores energy; oxygen is released as a byproduct.
---
9) In the absence of light, _photosynthesis_ stops and _respiration_ becomes the dominant process.
✔ *Explanation:* Without light, plants cannot run the light reactions, so photosynthesis halts. Cells then rely on cellular respiration to break down stored glucose for energy.
---
10) _Carbon fixation_, _reduction_, and _regeneration_ are the three stages of the Calvin Cycle.
✔ *Explanation:*
- Carbon fixation: CO₂ is attached to RuBP (catalyzed by Rubisco).
- Reduction: ATP and NADPH are used to convert 3-PGA into G3P (sugar precursor).
- Regeneration: Some G3P molecules are used to regenerate RuBP so the cycle can continue.
---
11) _Cellular respiration_ and photosynthesis are almost opposite reactions.
✔ *Explanation:* Photosynthesis: CO₂ + H₂O → glucose + O₂ (stores energy).
Respiration: glucose + O₂ → CO₂ + H₂O + ATP (releases energy). They are essentially reverse processes.
---
12) Glucose is a _carbohydrate_ used to provide energy.
✔ *Explanation:* Glucose (C₆H₁₂O₆) is a simple sugar (monosaccharide) and primary energy source for most living organisms.
---
13) Energy is released from the ATP when the _high-energy phosphate bond_ is broken and ADP is formed.
✔ *Explanation:* ATP has three phosphate groups. Breaking the bond between the 2nd and 3rd phosphates releases energy and forms ADP + inorganic phosphate (Pi).
---
14) _Chlorophyll_ is a green pigment in the plants that absorbs light energy.
✔ *Explanation:* Chlorophyll a and b absorb blue and red light best, reflecting green — which is why plants look green.
---
15) _ADP_ and _NADP⁺_ return to the thylakoid membrane for recycling.
✔ *Explanation:* After being used in the Calvin Cycle, ADP and NADP⁺ go back to the thylakoids to be recharged into ATP and NADPH during the light reactions.
---
✔ Final Answer Summary (for filling in blanks):
1) Light reactions, Calvin Cycle
2) Chloroplast
3) dark reaction (or light-independent reaction)
4) thylakoid membrane
5) granum
6) fluid-filled space
7) stroma
8) Glucose, oxygen
9) photosynthesis, respiration
10) Carbon fixation, reduction, regeneration
11) Cellular respiration
12) carbohydrate
13) high-energy phosphate bond
14) Chlorophyll
15) ADP, NADP⁺
---
Let me know if you’d like a diagram or mnemonic to help remember these concepts! 🌿☀️
---
1) _Light reactions_ and _Calvin Cycle_ are the two stages of photosynthesis.
✔ *Explanation:* Photosynthesis occurs in two main phases: the light-dependent reactions (which require sunlight to produce ATP and NADPH) and the Calvin Cycle (light-independent reactions that use ATP and NADPH to make glucose).
---
2) _Chloroplast_ is the site of photosynthesis in plants.
✔ *Explanation:* Chloroplasts are specialized organelles in plant cells containing chlorophyll and the machinery needed to convert light energy into chemical energy.
---
3) Calvin-Benson Cycle is also called a _dark reaction_ or _light-independent reaction_.
✔ *Explanation:* Although it doesn’t directly need light, it depends on products from the light reactions (ATP and NADPH). It’s often called the “dark reaction” because it can occur without direct light — but not without the products of light reactions.
---
4) Light reactions take place in the _thylakoid membrane_.
✔ *Explanation:* The thylakoid membranes inside chloroplasts contain chlorophyll and electron transport chains where light energy is converted into chemical energy (ATP and NADPH).
---
5) A _granum_ is a stack of thylakoids.
✔ *Explanation:* Thylakoids are disk-like sacs; when stacked together, they form structures called grana (singular: granum), which increase surface area for light absorption.
---
6) Stroma is a _fluid-filled space_ surrounding the thylakoids.
✔ *Explanation:* The stroma is the gel-like substance inside the chloroplast, outside the thylakoids. This is where the Calvin Cycle occurs.
---
7) The Calvin Cycle takes place in the _stroma_.
✔ *Explanation:* As mentioned above, the stroma contains enzymes needed to fix carbon dioxide into sugar using ATP and NADPH.
---
8) _Glucose_ and _oxygen_ are produced as a result of photosynthesis.
✔ *Explanation:* The overall equation is: 6CO₂ + 6H₂O + light → C₆H₁₂O₆ (glucose) + 6O₂. Glucose stores energy; oxygen is released as a byproduct.
---
9) In the absence of light, _photosynthesis_ stops and _respiration_ becomes the dominant process.
✔ *Explanation:* Without light, plants cannot run the light reactions, so photosynthesis halts. Cells then rely on cellular respiration to break down stored glucose for energy.
---
10) _Carbon fixation_, _reduction_, and _regeneration_ are the three stages of the Calvin Cycle.
✔ *Explanation:*
- Carbon fixation: CO₂ is attached to RuBP (catalyzed by Rubisco).
- Reduction: ATP and NADPH are used to convert 3-PGA into G3P (sugar precursor).
- Regeneration: Some G3P molecules are used to regenerate RuBP so the cycle can continue.
---
11) _Cellular respiration_ and photosynthesis are almost opposite reactions.
✔ *Explanation:* Photosynthesis: CO₂ + H₂O → glucose + O₂ (stores energy).
Respiration: glucose + O₂ → CO₂ + H₂O + ATP (releases energy). They are essentially reverse processes.
---
12) Glucose is a _carbohydrate_ used to provide energy.
✔ *Explanation:* Glucose (C₆H₁₂O₆) is a simple sugar (monosaccharide) and primary energy source for most living organisms.
---
13) Energy is released from the ATP when the _high-energy phosphate bond_ is broken and ADP is formed.
✔ *Explanation:* ATP has three phosphate groups. Breaking the bond between the 2nd and 3rd phosphates releases energy and forms ADP + inorganic phosphate (Pi).
---
14) _Chlorophyll_ is a green pigment in the plants that absorbs light energy.
✔ *Explanation:* Chlorophyll a and b absorb blue and red light best, reflecting green — which is why plants look green.
---
15) _ADP_ and _NADP⁺_ return to the thylakoid membrane for recycling.
✔ *Explanation:* After being used in the Calvin Cycle, ADP and NADP⁺ go back to the thylakoids to be recharged into ATP and NADPH during the light reactions.
---
✔ Final Answer Summary (for filling in blanks):
1) Light reactions, Calvin Cycle
2) Chloroplast
3) dark reaction (or light-independent reaction)
4) thylakoid membrane
5) granum
6) fluid-filled space
7) stroma
8) Glucose, oxygen
9) photosynthesis, respiration
10) Carbon fixation, reduction, regeneration
11) Cellular respiration
12) carbohydrate
13) high-energy phosphate bond
14) Chlorophyll
15) ADP, NADP⁺
---
Let me know if you’d like a diagram or mnemonic to help remember these concepts! 🌿☀️
Parent Tip: Review the logic above to help your child master the concept of photosynthesis worksheet 7th grade.
