የባዮሎጂ መግቢያ ፈተና፣ 2005 ዓ.ም. (2013)

Every biological membrane is built as a double sheet of phospholipids. Each phospholipid has a water loving head and two water hating tails, so in water the molecules line up automatically with the tails facing inward and the heads facing out. That bilayer is the sheet itself, and everything else sits inside it. Cholesterol is tempting because animal membranes really do contain it, but it is a small amount tucked between the phospholipids to control how stiff the membrane is, not the material the membrane is made from.

The savanna is open grassland with scattered trees and a long dry season. Grass grows back fast after rain and after grazing, so it can feed huge herds of elephants, giraffes and zebras, and those herds in turn feed lions and other big predators. The Congo rain forest is tempting because it holds more species than any other African biome, but its closed canopy leaves little food at ground level, so its large mammals are scattered forest animals rather than the big open plains herds.

The scientific method starts when you notice something, then you offer a possible explanation for what you noticed. That proposed explanation is the hypothesis, and it is what the rest of the work tests. Prediction is tempting, but a prediction is what you work out from a hypothesis you already have: without the hypothesis first, there is nothing to predict from.

The plant cell wall is made mainly of cellulose, long unbranched chains of glucose that lie side by side and bond to each other to form tough fibres. Those fibres give the wall its strength and keep the cell from bursting when water enters. Starch is tempting because it is also made of glucose, but starch chains coil into grains stored inside the cell as food, and they carry no structural strength. Chitin does build a wall, but in fungi rather than plants.

Amylases are the carbohydrate digesting enzymes. The name comes from amylum, the Latin word for starch, and salivary and pancreatic amylase both break starch down into maltose and then to glucose. Enzymes are usually named after what they act on, which is the quickest way to sort this list. Proteases are tempting only if the naming rule is missed: they act on proteins, not on sugars.

Monera is the kingdom of bacteria and related organisms, and these are prokaryotes: their DNA lies free in the cytoplasm with no nuclear membrane around it, and they have no mitochondria or other membrane bound organelles. Protista is the tempting answer because many protists are single celled and look simple, but a single celled amoeba or paramecium still has a true nucleus and organelles, which makes it a eukaryote.