SYI Photosynthesis

What is the primary function of chloroplasts in plant cells?

• ATP synthesis

• Photosynthesis

• Cellular respiration

• DNA replication

Answer explanation

The primary function of chloroplasts in plant cells is Photosynthesis. Chloroplasts are the sites of photosynthesis in green plants. Photosynthesis is the process where plants convert light energy, usually from the Sun, into chemical energy that can be later released to fuel the organisms' activities. This process is important for the growth and development of plants.

What is the typical size range of chloroplasts in plant cells?

• 1 - 5 μm

• 5 - 15 μm

• 2 - 10 μm

• 10 - 20 μm

Answer explanation

The correct size range of chloroplasts in plant cells is 2 - 10 μm. This size is typical for chloroplasts as they need to be small enough to move freely within the cell, but large enough to contain all the necessary components for photosynthesis.

What is the name of the double-membrane that surrounds each chloroplast?

• Chlorophyll bilayer

• Stroma membrane

• Chloroplast envelope

• Chloroplast matrix

Answer explanation

The question asks for the name of the double-membrane that surrounds each chloroplast. Among the given options, 'Chloroplast envelope' is the correct answer. This is because the chloroplast envelope is made of the inner, outer membranes and the intermembrane space.

What is the primary function of the inner membrane of a chloroplast envelope?

• Photosynthesis

• Protein synthesis

• Ion transport

• ATP production

Answer explanation

The primary function of the inner membrane of a chloroplast envelope is 'Ion transport'. This is because the inner membrane is responsible for the transport of ions across the envelope, playing a crucial role in maintaining the chloroplast's internal environment. It is not directly involved in photosynthesis, protein synthesis, or ATP production.

What is the name of the fluid found inside chloroplasts where CO2, sugars, and enzymes are dissolved?

• Thylakoid

• Grana

• Stroma

• Lumen

Answer explanation

The fluid found inside chloroplasts where CO2, sugars, and enzymes are dissolved is called Stroma. It is the site of the dark reactions in photosynthesis. Thylakoid, Lumen, and Grana are other parts of the chloroplast but they do not perform this particular function.

What is the name of the membrane system within the stroma of a chloroplast, which consists of flattened, fluid-filled sacs?

• Thylakoids

• Granules

• Lamellae

• Membranoids

Answer explanation

The correct answer is Thylakoids. In chloroplasts, the stroma is a fluid-filled internal space where a system of interconnected and flattened sacs, called Thylakoids, are present. These Thylakoids are the site of the light-dependent reactions of photosynthesis.

Thylakoids stack up to form structures known as what?

• Chloroplasts

• Stroma lamellae

• Grana

• Cytosol

Answer explanation

Thylakoids are sac-like membranes found inside chloroplasts. They are arranged in stacks known as grana. These grana play a crucial role in the processes of photosynthesis, where energy from light is converted into chemical energy. Therefore, thylakoids stack up to form structures known as Grana.

In which structures are pigment molecules arranged in light-harvesting clusters known as photosystems?

• Stroma lamellae

• Grana

• Thylakoids

• Cytosol

Answer explanation

Photosystems, including both Photosystem I and Photosystem II, are located in the thylakoid membranes of chloroplasts. These are the sites where light is converted into energy in photosynthetic organisms. These photosystems contain pigment molecules that absorb light and initiate photosynthesis. So, the correct answer is Thylakoids.

What is the function of chloroplast DNA (cpDNA) in chloroplasts?

• Producing ATP

• Storing carbohydrates

• Coding for some proteins

• Controlling ion transport

Answer explanation

Chloroplast DNA (cpDNA) is responsible for coding some proteins that are essential for the chloroplasts' function. These proteins are crucial in various processes such as photosynthesis. Therefore, the answer to the question 'What is the function of chloroplast DNA (cpDNA) in chloroplasts?' is 'Coding for some proteins'.

What type of pigments are found in chloroplasts that absorb different wavelengths of light?

• Chlorophylls

• Carbohydrates

• Lipids

• Proteins

Answer explanation

The pigments found in chloroplasts that absorb different wavelengths of light are Chlorophylls. Chlorophylls are crucial for photosynthesis, allowing plants to absorb energy from light. They are not Carbohydrates, Lipids or Proteins, which are different types of biomolecules with different functions.