Gold is a valuable metal that cannot be broken down into simpler substances by ordinary chemical means. What is the correct term for a substance like gold?

A biologist observes a cell with a rigid outer layer that provides structural support. The cell also contains a large central vacuole. What type of cell is she most likely observing?

Small, nonpolar molecules, such as oxygen (O2​) and carbon dioxide (CO2​), can pass directly through the cell’s plasma membrane without the help of a transport protein. Why is this possible?

During the citric acid cycle (Kreb’s cycle), molecules such as NAD+ and FAD are reduced to form NADH and FADH2​. What is the importance of these molecules in the overall process of cellular respiration?

An oak tree is a multicellular organism. All of its cells, including those in its leaves and roots, contain a membrane-bound nucleus that holds its DNA. What type of cell makes up the oak tree?

A scientist discovers a new single-celled organism living in a deep-sea hydrothermal vent. The organism lacks a nucleus but its genes are more closely related to those of eukaryotes than to those of bacteria. What domain would this organism most likely belong to?

A human consumes a plant for energy. What is the scientific term for an organism that obtains its energy by consuming other organisms?

During the Calvin cycle in photosynthesis, the molecule NADPH donates electrons to a molecule to form a sugar. What happens to the molecule that receives the electrons?

Water, with the chemical formula H2​O, consists of two hydrogen atoms covalently bonded to one oxygen atom. What is the correct term for this substance?

Humans are classified with the scientific name Homo sapiens. What do the two parts of this name refer to?