A huge branched polymer is built from identical six-carbon ring units, each made from one C6H12O6. A liver cell strips units off the branch ends within seconds when fuel is needed. Which group does it belong to?

A molecule has a three-carbon glycerol backbone with three long hydrocarbon chains attached. It contains many carbon-hydrogen bonds, very little oxygen and no nitrogen. To which group of macromolecules does it belong?

Two long strands twist around each other. Each strand is a chain of repeating units, and every unit is a phosphate group, a five-carbon sugar and one of four nitrogen-containing bases. Which group of macromolecules is this?

A chain of 124 linked units folds into one precise three-dimensional shape. Each unit has a central carbon bonded to a hydrogen, an amino group, a carboxyl group and one of 20 different side groups. Which group is it?

A molecule sits inside a cell membrane. Its carbon skeleton is four rings fused together, it carries almost no charged groups, and it does not dissolve in water. Which group of macromolecules does it belong to?

Two six-carbon ring units join, a water molecule is released, and the product has the formula C12H22O11. Which group of macromolecules does the product belong to?

A single-stranded molecule leaves the nucleus. Its repeating units each contain a phosphate group, the sugar ribose, and one of four bases including uracil. Which group of macromolecules is it?

In a polymer, each new unit is added by a bond formed between the carboxyl group of one unit and the amino group of the next, releasing water each time. Which group of macromolecules is being built?

A molecule has a phosphate-containing head that interacts freely with water and two long hydrocarbon tails that do not. Thousands of them line up tail to tail in a double layer. Which group of macromolecules is this?

Thousands of glucose units are linked into long, straight, unbranched chains. The chains lie side by side and hydrogen bond to one another, making tough fibers that humans cannot digest. Which group is this molecule in?

Butter is solid at room temperature, separates from water instead of dissolving, and supplies about 7 kilocalories per gram. Almost all of that mass belongs to which group of macromolecules?

Raw egg white is clear and runny. Heated in a pan it turns solid and opaque and never returns to liquid, because its folded chains lose their shape. Which group of macromolecules is egg white mostly made of?

Cells in a raw potato are packed with microscopic storage grains. Each grain is built from thousands of glucose units linked into coiled chains. Which group of macromolecules are the grains made of?

Hair, fingernails and the tough outer layer of skin are built largely from keratin, a fibrous material of long folded chains bonded to each other by sulfur bridges. Which group of macromolecules is keratin?

A biologist stains a dividing cell and photographs its chromosomes. The material coiled up inside each chromosome carries the cell's inherited instructions. Which group of macromolecules is that material?

The strings in a celery stalk and the wood of a tree trunk are stiff, insoluble and give the plant its support. Which group of macromolecules makes up these plant cell walls?

The tissue stored under a person's skin holds more than twice as much energy per gram as the same mass of anything else the body stores. Which group of macromolecules is that stored material?

A bacteriophage lands on a bacterium, stays outside, and injects material into the cell. That material alone makes the bacterium build hundreds of new phage particles. Which group of macromolecules was injected?

Honey is about 80% fructose and glucose by mass. It dissolves completely in water, tastes sweet, and supplies about 3 kilocalories per gram. Apart from water, which group of macromolecules is honey almost entirely made of?

Beeswax is secreted from glands on a worker bee's abdomen. It is firm, waterproof, made of long hydrocarbon chains, and floats on water without dissolving. Which group of macromolecules is beeswax?

A student heats a food sample with Benedict's solution and the tube turns from blue to orange-red. A second sample of the same food stays yellow-brown when iodine solution is added. What does the food contain?

Biuret reagent added to a food sample changes from blue to violet. Sudan III added to a fresh portion of the same sample produces no red-stained layer. What does this pair of results show about the food?

A student rubs a food sample on brown paper. Twenty minutes later the paper still has a translucent spot that light passes through, and the spot has not dried out. Which group of macromolecules did this test detect?

Iodine solution dropped onto a slice of raw potato turns blue-black within seconds. Which group of macromolecules has the iodine detected in the potato?

Biuret reagent added to a sample of raw egg white turns from pale blue to violet. Which group of macromolecules does this color change identify?

A few drops of Sudan III are shaken with a food sample. The mixture separates and the upper layer is stained bright red. Which group of macromolecules is in that upper layer?

A starch solution gives a blue-black iodine result and a negative Benedict's result. Saliva is added and the tube is left warm. An hour later iodine gives no color change and Benedict's turns brick red. What happened?

Whole milk gives a violet result with Biuret reagent and a lasting translucent spot on brown paper, but stays yellow-brown with iodine. Which two groups of macromolecules has the student shown milk contains?

Apple juice heated with Benedict's solution turns brick red. The same juice stays yellow-brown with iodine and pale blue with Biuret reagent. Which group of macromolecules supplies almost all of the juice's food energy?

A student runs every food test on a tube of distilled water and records no color change in any of them. Why does the class run this tube alongside the food samples?

A molecule in a cell lowers the activation energy of one reaction. It has a pocket shaped to fit a single substrate, it is not used up, and it stops working permanently once the cell reaches 60 degrees Celsius. Which group is it in?

Before a cell divides, one kind of molecule is copied so that each daughter cell receives a full set of the instructions for building every enzyme the cell needs. Which group of macromolecules is copied?

The pancreas releases a molecule into the bloodstream after a meal. It binds a receptor on liver and muscle cells and signals them to take glucose out of the blood. Which group of macromolecules is this signal?

The barrier around every cell is two molecules thick and keeps water-soluble substances from drifting in or out on their own. Which group of macromolecules forms that double layer?

A leaf makes a molecule during daylight and ships it down the stem to the roots, where cells break it apart to release the energy stored in its bonds. Which group of macromolecules is being transported?

A copy of one gene's message is made inside the nucleus, passes through a nuclear pore, and is read by a ribosome in the cytoplasm. Which group of macromolecules carries that message?

A thick layer under a seal's skin keeps its body warm in near-freezing water and is drawn on for energy during months when the seal does not feed. Which group of macromolecules is that layer?

A beetle's rigid exoskeleton is made of a polymer of linked nitrogen-containing glucose units. It gives the body support and shape and is shed whole when the beetle molts. Which group of macromolecules is it?

After an infection, a person's blood carries Y-shaped molecules whose tips fit one particular bacterium and no other. Which group of macromolecules are these molecules?

Short branched chains stick out from the surface of a red blood cell. They are built from linked units such as galactose and fucose, and the unit at the tip decides whether blood is type A or B. Which group of macromolecules are they?