Cell Structure And Specialised Cells

The nucleus is the part of a cell that contains the genetic information. It is often referred to as the "control center" of the cell because it houses the cell's DNA, which carries the instructions for the cell's growth, development, and functioning. The nucleus is surrounded by a nuclear membrane, which helps protect the DNA and regulate the movement of molecules in and out of the nucleus. Within the nucleus, the DNA is organized into structures called chromosomes, which contain the genes that determine an organism's traits.

A ribosome is where protein synthesis occurs. Ribosomes are small organelles found in cells that are responsible for translating the genetic information from DNA into proteins. They do this by linking amino acids together in a specific order to form a polypeptide chain, which then folds into a functional protein. Ribosomes can be found in both the cytoplasm of the cell and on the endoplasmic reticulum. They are composed of RNA and proteins and are essential for the proper functioning of cells.

Ribosomes are the correct answer because they are responsible for protein synthesis in a cell. Ribosomes are small structures found in the cytoplasm of a cell and on the rough endoplasmic reticulum. They read the genetic information from the nucleus and use it to assemble amino acids into proteins. Therefore, the location inside a cell where proteins are made is the ribosomes.

The correct answer is the cell membrane. The cell membrane is a selectively permeable structure that allows certain substances to pass through while restricting the passage of others. It controls the movement of molecules in and out of the cell, maintaining the cell's internal environment and regulating cellular processes. This partially permeable nature of the cell membrane is essential for cellular homeostasis and proper functioning.

Mitochondria are the correct answer because they are the powerhouse of the cell and are responsible for producing energy in the form of ATP through cellular respiration. Flight muscles require a lot of energy to function, so it makes sense for them to have many mitochondria to meet their high energy demands. Nuclei, vacuoles, and membranes are also present in cells, but they do not play a direct role in energy production like mitochondria do.

Osmosis is the movement of solvent molecules (in this case, water) from an area of lower solute concentration to an area of higher solute concentration, across a semipermeable membrane. Glucose, hydrogen peroxide, and oxygen are not substances that typically move in osmosis. Therefore, the correct answer is water.

Ribosomes, mitochondria, and cytoplasm are found in both plant and animal cells. These are essential components for various cellular functions:

Ribosomes: Protein synthesis

Mitochondria: Energy production (cellular respiration)

Cytoplasm: Provides structure and supports other organelles within the cell.

Nucleus is the control center of the cell, containing genetic material (DNA) and directing cellular activities. It's present in both plant and animal cells.

Vacuole is a large sac for storage and waste disposal. It's a prominent feature in plant cells, helping them maintain turgor pressure (cell rigidity) and storing various substances. Animal cells may have small vacuoles, but they are not as significant as in plant cells.

A cell membrane is partially permeable because it allows certain substances to pass through while restricting the movement of others. It is selectively permeable, meaning it has specific channels and transporters that control the movement of molecules and ions in and out of the cell. This allows the cell to maintain a stable internal environment by regulating the passage of essential substances like water and nutrients, while preventing the entry of harmful substances or the loss of important cellular components.

Aerobic respiration occurs in the mitochondria of a cell. Mitochondria are often referred to as the "powerhouses" of the cell because they are responsible for producing most of the cell's energy in the form of ATP through aerobic respiration. This process involves the breakdown of glucose and other molecules in the presence of oxygen to produce ATP, carbon dioxide, and water. The mitochondria have specialized structures and enzymes that facilitate this energy production process, making them the site of aerobic respiration in cells.

Cellulose is a complex carbohydrate made up of glucose molecules linked together. These glucose molecules are the sugar component of cellulose. Cellulose is a major structural component of plant cell walls and provides rigidity and support to plants. It cannot be digested by humans and is considered a dietary fiber.

When the concentration of internal and external cell solutions is the same, there is no concentration gradient to drive the movement of water. As a result, water molecules will move randomly in both directions, causing an equal movement of water into and out of the cell. This is known as dynamic equilibrium, where the net movement of water is zero. Therefore, the correct answer is "It moves equally both ways."

When plant cells are placed in a very dilute solution, water enters the cells by osmosis. This causes the cells to swell and expand, becoming turgid. The cell walls prevent the cells from bursting, allowing them to maintain their shape. This expansion of the cells helps to provide support to the plant, making it more rigid and upright.

While both animal and plant cells can contain vacuoles, the presence of a large central vacuole is characteristic of plant cells, not animal cells. Plant cells typically have a single large vacuole that plays a crucial role in maintaining turgor pressure, which helps support the plant's structure. In contrast, animal cells may have smaller, more numerous vacuoles used primarily for storage and transport but do not typically feature a large central vacuole. Therefore, specifying "large vacuole" as a structure not found in animal cells is accurate.

When the temperature of the external solution increases, the kinetic energy of the water molecules also increases. This increased kinetic energy leads to more collisions between the water molecules and the cell membrane, causing more water molecules to enter the cell by osmosis. Therefore, increasing the temperature of the external solution results in more water entering the cell.