AboutJohn Locke Expertise I will answer all biology-related questions through the undergraduate level. I will explain unclear concepts and suggest approaches to solving problems, but would prefer not to completely solve homework problems for you. If you are completely stumped on homework, tell me what you already know and I will help you as much as possible. Please do not ask me for ideas on school research projects; part of research is determining a suitable area of investigation, and that's not a task that should be completed by someone else.
Experience I have a BS in Bioengineering with a concentration in Chemical Engineering (which included a heavy focus on biology), and have taught biology, biochemistry, and related subjects for some time now.
Education/Credentials BS Bioengineering, Penn State University
MCAT/DAT/OAT Instructor
Question What is absent from a bacterial cell?
Why are gases hotter than liquids or solids?
Answer Thanks for using AllExperts. These questions are fairly vague and broad, but I can help direct as to their answers. Bacteria lack membrane-bound organelles; as you may know, organelles are complex, specialized subunits within a cell that have specific functions. The lack of well-defined, membrane-bound organelles is characteristic of bacteria, which are called prokaryotes (as opposed to eukaryotes, which have organelles that are surrounded by membranes. All other cells that are not bacteria are eukaryotes). This is the one major characteristic that is absent in bacteria but present in all eukaryotic cells. A brief discussion can be found here:
As to the second question, I cannot really tell what the questioner is looking for. Gases are not hotter than liquids or solids. If we describe heat content (hotness) as measured by temperature, then it's easy to see that gases are not necessarily hotter than liquids or solids; gases can achieve any temperature from almost absolute zero up through billions of degrees. A gas (let's say air) can be at room temperature while a solid (let's say ice) can simultaneously be at 0 degrees Celsius, colder than the air in the room.
I suspect that the question is asking about a scenario in which a solid, liquid, and gas are all at the same temperature. In that case, the gas has a higher average kinetic energy than the liquid or solid. That is to say that the gas molecules move faster than the molecules in the solid or liquid; gas molecules always move faster than those in a solid or liquid at a given temperature because the molecules can move about freely. A gas has no defined shape or volume, while liquids and solids have a defined shape and/or volume; this necessarily means that liquids and solids have slower-moving, more restricted molecules. All that said, it is not correct that gases are hotter than liquids or solids.
