Cells Test Review

Explanation
Viruses are not considered living organisms because they lack the ability to reproduce and carry out metabolic processes on their own. They are essentially just genetic material (DNA or RNA) enclosed in a protein coat. Viruses can only replicate by invading the cells of a host organism and hijacking their cellular machinery. Outside of a host, viruses are inert and do not exhibit any characteristics of life. Therefore, the correct answer is false.

Explanation
The example of bacteria is an example of prokaryotic cells. Prokaryotic cells are characterized by the absence of a nucleus and other membrane-bound organelles. Bacteria are single-celled organisms that belong to the prokaryote domain. They have a simple cell structure with a cell membrane, cytoplasm, and genetic material that is not enclosed within a nucleus. Therefore, the correct answer is Prokaryotic.

Explanation
The cell membrane is composed of two main biomolecules: proteins and lipids. Proteins play a crucial role in the cell membrane as they act as channels, receptors, and transporters, allowing substances to enter and exit the cell. Lipids, specifically phospholipids, make up the majority of the cell membrane structure. They form a lipid bilayer, with hydrophilic heads facing the aqueous environment and hydrophobic tails facing each other. This arrangement provides a barrier that separates the inside of the cell from the outside environment. Together, proteins and lipids ensure the integrity and functionality of the cell membrane.

Explanation
The correct answer is "New cells come from already existing cells." This statement is related to the part of the cell theory that states cells can only arise from pre-existing cells. When your skin is injured and a cut forms, new cells are generated from existing cells in order to repair the damaged tissue and form a scab. This process is an example of cell division and regeneration, which is a fundamental principle of the cell theory.

Explanation
Chloroplast is the correct answer because it is a cell organelle that is unique to plants. It is responsible for the process of photosynthesis, converting sunlight into energy. Chloroplasts contain chlorophyll, which gives plants their green color and allows them to capture light energy. Unlike mitochondria, nucleus, and lysosomes, chloroplasts are not found in animal cells.

Explanation
Bacteria is an example of a prokaryotic cell because it lacks a nucleus and membrane-bound organelles. Prokaryotic cells, like bacteria, have genetic material that is not enclosed within a nucleus and their internal structure is relatively simple compared to eukaryotic cells. Bacteria are single-celled organisms that can be found in various environments and play important roles in various biological processes.

Explanation
The cell wall is a rigid layer that surrounds the plant cells and provides structural support and protection. It acts as a barrier against mechanical stress and helps prevent the cell from bursting due to osmotic pressure. The cell wall also protects the plant cells from pathogens and physical damage. Therefore, the statement "Cell wall protects the cells of plants" is true.

Explanation
Chloroplast organelles are actually found in plant cells, not animal cells. They are responsible for photosynthesis, the process by which plants convert sunlight into energy and produce their own food. Animal cells do not have chloroplasts and therefore cannot use them to make their own food. Hence, the given statement is false.

Explanation
The correct answer is "All of the above" because all the options listed are examples of eukaryotic cells. Eukaryotic cells are characterized by having a true nucleus and membrane-bound organelles. Blood cells, muscle cells, and amoebas are all examples of eukaryotic cells found in different organisms.