AP Biology : Understanding Chloroplasts

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #1 : Understanding Chloroplasts

Which of the following structures is unique to plant cells?

Possible Answers:

Lysosomes

Endoplasmic reticulum

Chloroplasts

Mitchondria

Vacuoles

Correct answer:

Chloroplasts

Explanation:

Chloroplasts are organelles in plant cells that conduct photosynthesis; therefore they are unique to plant cells. All the other mentioned organelles can be found in both animal and plant cells.

Example Question #2 : Cellular Structures

Which of the following can be found in plant cells, but not animal cells?

Possible Answers:

Mitochondria

Chloroplasts

Ribosomes

Cell membrane

Correct answer:

Chloroplasts

Explanation:

Chloroplasts, the site of photosynthesis, are only in plant cells and are not found in animal cells. Ribosomes, a cell membrane, and a mitochondria, however, can be found in both animal and plant cells.

The other structure that may be found in plant cells, but not animal cells, is a cell wall.

Example Question #1 : Understanding Chloroplasts

Where in the chloroplasts does the Calvin Cycle of photosynthesis take place?

Possible Answers:

Intermembrane space

Thylakoid membrane

Stroma

Thylakoid lumen

Grana

Correct answer:

Stroma

Explanation:

The Calvin Cycle occurs in the stroma, the aqueous fluid-filled area of the chloroplast. The stroma can be seen as analogous to the cytoplasm of a cell, in that it is the liquid in which all other substructures reside. The other processes of photosynthesis, the light-dependent reactions, take place in the thylakoid, a membrane-bound substructure within the chloroplast.

Example Question #1 : Understanding Chloroplasts

Which of the following terms can be described as the green pigment located within chloroplasts?

Possible Answers:

Chlorophyll

Mesophyll

Photoreceptors

Stomata

Correct answer:

Chlorophyll

Explanation:

Chlorophyll is what gives plants their green color. The chlorophyll located in the chloroplasts captures the light energy that drives the synthesis of food molecules in the chloroplasts—photosynthesis.

Example Question #2 : Understanding Chloroplasts

Which of the following best describes where chloroplasts are primarily located?

Possible Answers:

Roots

Mesophyll

Stomata

Stroma

Correct answer:

Mesophyll

Explanation:

Chloroplasts are found mainly in the cells of the mesophyll, which is the tissue in the interior of the leaf. Stomata are the pores that allow carbon dioxide to enter and oxygen to exit the leaf. The stroma is the dense fluid content of the chloroplast.

Example Question #1 : Understanding Chloroplasts

What is the organelle in plant cells that contains chlorophyll?

Possible Answers:

Golgi apparatus

Smooth endoplasmic reticulum

Chloroplasts

Mitochondria

Correct answer:

Chloroplasts

Explanation:

Chloroplasts are the organelles that contains chlorophyll. Mitochondria produce ATP and are not directly involved in capturing light and photosynthesis. The Golgi apparatus is involved in packaging substances, and Smooth endoplasmic reticulum are involved in lipid production.

Example Question #3 : Understanding Chloroplasts

Inside the chloroplast, what is the name of a stack of thylakoids?

Possible Answers:

Granum

Thylakoidum

Mitochondria

Stroma

Correct answer:

Granum

Explanation:

A stack of thylakoids is known as granum. Stroma is the region outside the thylakoid membranes, but still inside the chloroplast. Mitochondria is the organelle that produces ATP, and there is no such organelle called thylakoidum.

Example Question #1 : Understanding Chloroplasts

Which process is incorrectly matched with its location?

Possible Answers:

in the light dependent reaction, protons flow down their electrochemical gradient from the thylakoid lumen into the stroma, through the ATP synthase protein

carbon fixation during the light independent reaction occurs in the thylakoid stroma

in the light independent reaction, G3P is produced in the thylakoid stroma

in the light dependent reaction, protons are pumped from the thylakoid stroma into the lumen

Correct answer:

in the light dependent reaction, protons flow down their electrochemical gradient from the thylakoid lumen into the stroma, through the ATP synthase protein

Explanation:

During the light dependent reaction, protons are pumped from the thylakoid stroma into the lumen. Then, these protons flow down their electrochemical gradient (from high concentration to low concentration), through the ATP synthase protein, producing ATP.

Example Question #1 : Understanding Chloroplasts

Where is chlorophyll located?

Possible Answers:

Thylakoid membrane

Intermembrane space

Thylakoid stroma

Mitochondrial membrane

Correct answer:

Thylakoid membrane

Explanation:

Chlorophyll is used to capture sunlight during the light dependent reaction; the excited electrons then flow down the electron transport chain located on the thylakoid membrane.

Example Question #2 : Understanding Chloroplasts

During the light dependent reaction, the proton gradient is established. Where is the concentration of protons the greatest?

Possible Answers:

thylakoid membrane

thylakoid lumen

thylakoid stroma

intermembrane space

Correct answer:

thylakoid lumen

Explanation:

During the light dependent reaction, protons are pumped from the thylakoid stroma into the lumen. Then, these protons flow down their electrochemical gradient (from high concentration to low concentration), through the ATP synthase protein, producing ATP.

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