Unit Two: Cells Bacteria & Viruses: The Parts Of The Cell

Explanation
The cell membrane is the correct answer because it is responsible for controlling the entry and exit of substances in an eukaryotic cell. It is composed of a lipid bilayer, which allows it to regulate the movement of molecules in and out of the cell. The cell membrane also plays a crucial role in maintaining the cell's internal environment and protecting it from external factors.

Explanation
The correct answer is Cell Wall. The cell wall is a rigid layer that surrounds the cell membrane in plant cells. It provides structural support and protection to the cell, helping to maintain its shape and prevent it from bursting or collapsing. The cell wall is made up of cellulose fibers and other components, and it also allows for the exchange of substances between neighboring cells. The nucleus, cell membrane, and microtubules are important components of the cell, but they do not specifically serve as the protection barrier that keeps the cell shape together in plant cells.

Explanation
The nucleus is responsible for directing the making of proteins in a cell. This is because it contains the cell's DNA, which carries the instructions for protein synthesis. The DNA is transcribed into messenger RNA (mRNA) in the nucleus, and then the mRNA is transported to the ribosomes in the cytoplasm, where protein synthesis occurs. Therefore, the nucleus plays a crucial role in protein production within the cell.

Explanation
The endoplasmic reticulum is a network of membranes inside the cell that is responsible for the synthesis, folding, and transport of proteins and lipids. It consists of two types: rough endoplasmic reticulum (RER), which is studded with ribosomes and involved in protein synthesis, and smooth endoplasmic reticulum (SER), which lacks ribosomes and is involved in lipid metabolism and detoxification. The endoplasmic reticulum acts as a pathway for molecules to move within the cell, allowing for the efficient transport of proteins and lipids to their proper destinations.

Explanation
Mitochondria is the correct answer for this question because it is a maze-like organelle that provides energy for the cell. Mitochondria are often referred to as the powerhouse of the cell because they produce adenosine triphosphate (ATP), which is the main source of energy for cellular activities. They have a unique structure with inner and outer membranes, and their own DNA. Vacuoles are responsible for storage, ribosomes are involved in protein synthesis, and flagella are responsible for cell movement. Therefore, none of these options provide energy for the cell like mitochondria do.

Explanation
Vacuoles are the sacs that store water, food, and waste inside a plant cell. They are membrane-bound organelles that play a crucial role in maintaining the cell's shape and turgidity. Vacuoles also serve as storage compartments for nutrients, ions, and waste products. They help regulate the cell's internal environment, control osmotic pressure, and aid in the breakdown and recycling of cellular waste materials. Therefore, vacuoles are responsible for storing and managing various substances within a plant cell.

Explanation
The double membrane chloroplast located in a plant cell performs multiple functions. It absorbs sunlight through the pigment chlorophyll, which is essential for photosynthesis. This process converts sunlight into chemical energy, allowing the plant to produce glucose and oxygen. Additionally, chloroplasts contain pigments other than chlorophyll, giving plants their characteristic green color. Therefore, the correct answer is "All of the above" as the chloroplast is involved in absorbing photosynthesis, using sun energy, and giving color to plants.