Name that Molecule
Sugar in a grape belongs to which molecule group?
Carbohydrates
A bee uses sugar from nectar to power its flight. What do the sugars provide?
Energy
A bird eats a seed containing starch. Can the starch help supply energy for flying?
Yes. Starch is a carbohydrate that can provide energy.
“Only animals contain DNA.” Is this correct? Give another example.
No. Plants, such as strawberries or trees, contain DNA too.
A potato stores starch that can provide energy for new growth. Which molecule group is being stored?
Carbohydrates
Olive oil is mostly made of which molecule group?
Lipids
A bear stores fat before winter. How can that fat help when food is scarce?
It stores energy the bear can use later.
A squirrel cannot find food for a short time. How might its stored body fat help?
It can provide energy while food is unavailable.
“Lipids store _light_, and some help form cell membranes” Correct this statement.
Lipids store _energy_, and some help form cell membranes.
A duck has oil on its feathers that helps repel water.
Oil belongs to which molecule group?
Lipids
A bird’s growing feathers contain keratin.
Keratin is a material that builds body structures.
Which molecule group does it belong to?
Proteins
A person's body makes new tissue to heal a cut. What job are proteins doing?
Building and repairing tissue
A puppy’s cells cannot make enough proteins to build new tissue. How might this affect the puppy?
Its growth could slow, and tissue repair could be affected.
“A bean contains protein, so it cannot contain carbohydrates.” What is wrong with this reasoning?
A food can contain more than one molecule group.
A spider makes silk to build its web.
Silk contains long chains of amino acids.
Which molecule group makes up the silk?
Proteins
A strawberry’s cells contain DNA. Which molecule group does DNA belong to?
Nucleic Acids
A plant grows new cells. Why do those cells need lipids even if they aren’t storing much energy?
Some lipids help form cell membranes.
A plant cell cannot make the lipids it needs for new membranes. What problem might occur as the plant grows?
It could have trouble forming membranes for new cells.
“RNA is the ingredients in our cookbook comparison.” What should the ingredients and copied recipe represent?
Amino acids are the ingredients; messenger RNA is the copied recipe.
A tiny bacterium has no nucleus, but it still has DNA containing genetic instructions. Which molecule group does that DNA belong to?
Nucleic acids
A seed contains starch, oil, proteins, and DNA. Does it contain just one molecule group? Explain.
No. It contains all four groups, which have different jobs.
A growing turtle needs both DNA and proteins. Explain why one cannot simply replace the other.
DNA stores instructions; proteins help build the turtle’s tissues and perform other jobs.
Imagine a cell has amino acids—the ingredients for proteins—but cannot access the instructions for putting them together. Would ingredients alone be enough? Explain.
No. The cell also needs instructions to put the amino acids in the correct order.
“A plant has sunlight, so it doesn’t need proteins, lipids, or DNA.” Explain why this is incorrect.
Sunlight supplies energy for photosynthesis, but plants still need proteins to build and repair, lipids for membranes, and DNA for instructions.
A seedling needs stored energy, materials for building tissues, and genetic instructions. Its seed contains oil, proteins, and DNA. Which molecule group is represented by each substance?
Oil: lipids
Proteins: proteins
DNA: nucleic acids