Answer:
Structure: unicellular organisms (single-celled), no nucleus or membrane-bound organelles, genetic material usually composed of a single circular bacterial chromosome coiled up in a region of the cytoplasm
Function: metabolic functions are carried out in the bacterial cytoplasm
Replication: generally asexual (binary fission)
Explanation:
Bacteria are prokaryotic organisms, i.e., unicellular organisms that do not have a cell nucleus nor any membrane-bound organelles
. Generally, the genetic material is composed of a single DNA circular molecule (bacterial chromosome), which is localized in a specific region of the cytoplasm (nucleoid region). Prokaryotic cells are usually smaller than eukaryotic cells (0.1 - 5 μm in size). In bacteria, metabolic functions (i.e., growth and reproduction) occur in the cytoplasm. The most important process of reproduction in bacteria is binary fission, a form of asexual reproduction where a single bacterial cell divides into two. Bacteria can also exchange genetic material by sexual reproduction mechanisms (i.e., conjugation, transformation and transduction). The main strategy to prevent outbreaks caused by bacteria is to know the conditions where they grow and reproduce. For example, <em>Salmonella</em> is a genus of infectious bacteria that may cause an outbreak. <em>Salmonella</em> infection may be prevented by eliminating conditions where they can multiply. Measures to prevent <em>Salmonella</em> outbreaks include cook food thoroughly (do not eat raw eggs or raw beef), refrigerate foods, wash hands, etc.
(1) they keep toxic substances out of the cell;
(2) they contain receptors and channels that allow specific molecules, such as ions, nutrients, wastes, and metabolic products, that mediate cellular and extracellular activities to pass between organelles and between the cell and the outside environment;
(3) they separate vital but incompatible metabolic processes conducted within organelles.
I believe the answers are A. C. D.
Receptors which provide animals with information from the external environment are located in ears, tongue, eyes, and the nose. These are all receptors that can be found in our sensory organs and provide us with feedback from our nearby environment and the stimuli on which we should be alerted towards.
