Biology Quiz

What are guard cells?

• Cells that transport nutrients.

• Specialized cells that control the opening and closing of stomata.

• Cells that store water.

• Cells that produce chlorophyll.

Answer explanation

Guard cells are specialized cells found in plants, which control the opening and closing of stomata - tiny openings used for gas exchange. They help in the regulation of gas exchange and water balance in plants. Other cell types listed, such as those that transport nutrients, store water, or produce chlorophyll, don't perform the same function.

What is photosynthesis?

• The process by which green plants and some other organisms use moonlight to synthesize foods with the help of chlorophyll pigment in their cells.

• The process by which green plants and some other organisms use sunlight to break down foods with the help of chlorophyll pigment in their cells.

• The process by which green plants and some other organisms use sunlight to synthesize water with the help of chlorophyll pigment in their cells.

• The process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll pigment in their cells.

Answer explanation

Photosynthesis is the process by which green plants and other certain organisms use sunlight, not moonlight, to synthesize foods. This isn't a process of breaking down foods or synthesizing water. It specifically involves the synthesis of food with the aid of chlorophyll pigment present in their cells.

What is the chemical equation for photosynthesis?

• C6H12O6 + 6O2 -> 6CO2 + 6H2O

• 6CO2 + 6H2O -> C6H12O6 + 6O2 + Energy

• C6H12O6 + 6O2 + Energy -> 6CO2 + 6H2O

• 6H2O+ 6CO2 -> 6O2 + C6H12O2

Answer explanation

The correct chemical equation for photosynthesis is '6H2O+ 6CO2 -> 6O2 + C6H12O2'. In this process, plants take in carbon dioxide and water, and with the help of sunlight, they produce glucose and oxygen. So, the equation must include water and carbon dioxide as reactants and glucose and oxygen as products.

What are stomata?

• Tiny hairs on the surface of plant leaves.

• The process of water loss through plant leaves.

• Small openings on the surface of plant leaves

• The cells responsible for photosynthesis in plant leaves.

Answer explanation

Stomata are small openings on the surface of plant leaves. They are not tiny hairs or the process of water loss, which is called transpiration. They are also not the cells responsible for photosynthesis—that's the job of chloroplasts. Stomata allow for gas exchange, letting carbon dioxide in for photosynthesis and letting oxygen out.

What is the main function of guard cells?

• Control the production of chlorophyll.

• Transport water and nutrients to the plant.

• Protect the plant from herbivores and pathogens.

• Regulate the opening and closing of stomata

Answer explanation

The main function of guard cells in plants is to regulate the opening and closing of stomata. Stomata are small openings on the surface of leaves that allow for gas exchange. While other options like controlling the production of chlorophyll, transporting water and nutrients, and protecting the plant from herbivores and pathogens are functions of different plant cells, they are not the main function of guard cells.

Where are stomata usually found?

• in the roots of plants

• in the flowers of plants

• on the bottom of the leaf of a plant

• in the fruits of plants

Answer explanation

Stomata are minute openings or pores found mainly on the underside of a plant's leaf. They facilitate gas exchange, allowing the plant to 'breathe'. The options provided mentioned roots, flowers, and fruits of plants. While these parts have their distinct functions, they are not where stomata are usually located. Therefore, the correct answer is that stomata are found on the bottom of the leaf of a plant.

What gas is released during photosynthesis?

• carbon dioxide

• oxygen

• methane

• nitrogen

Answer explanation

During photosynthesis, plants take in carbon dioxide and release oxygen as a by-product. This process is crucial for life on Earth as it generates the oxygen we breathe. Out of the given options, only oxygen aligns with this explanation, making it the correct choice.

What is the primary organelle involved in photosynthesis in plants?

• chloroplast

• hemoglobin

• melanin

• carotene

Answer explanation

The primary organelle involved in photosynthesis in plants is the chloroplast. This is because chloroplasts contain chlorophyll, a pigment which absorbs light energy for photosynthesis. Hence, the chloroplast is the correct answer, while hemoglobin, melanin, and carotene are irrelevant in this context.

What is the purpose of photosynthesis in plants?

• To convert sunlight, water, and nitrogen into glucose and oxygen.

• To convert moonlight, water, and carbon dioxide into glucose and oxygen.

• To convert sunlight, water, and carbon dioxide into glucose and carbon monoxide.

• To convert sunlight, water, and carbon dioxide into glucose and oxygen.

Answer explanation

The purpose of photosynthesis in plants is to convert sunlight, water, and carbon dioxide into glucose and oxygen. This answer is correct because photosynthesis is the process by which green plants use sunlight to synthesize foods with the help of carbon dioxide and water. The product of this reaction is glucose, which provides energy to the plants, and oxygen, which is released to the environment.

What is the role of stomata in photosynthesis?

• Stomata allow for the exchange of gases during photosynthesis.

• Stomata release oxygen during photosynthesis.

• Stomata produce glucose during photosynthesis.

• Stomata absorb sunlight during photosynthesis.

Answer explanation

The role of stomata in photosynthesis is to facilitate the exchange of gases. This process includes the intake of carbon dioxide and the release of oxygen, which are crucial for photosynthesis. Contrary to the other options, stomata do not directly produce glucose or absorb sunlight during the process.