Science Assessment ~ Ideas ~ All organisms need food as a source of molecules that provide chemical energy and building materials.

Key Idea: Animals use carbon-containing molecules from food to make a variety of other carbon-containing molecules that become part of their body structures.

Sub-Ideas
Items & Student Performance
Misconceptions
NGSS

Students are expected to know that:

Growth, repair, and replacement of body structures involves using carbon-containing molecules (carbohydrates, fats, and proteins) from food to make other carbohydrate, fat, and protein molecules that become part of their body structures.
Growth of animals requires the addition of molecules made up of linked carbon atoms to body structures, and this is the only way that body structures can grow.
The processes by which molecules from food become part of an animal’s body structures involve chemical reactions in which the atoms of the molecules from food (carbohydrates, fats, and proteins) are rearranged to form new molecules of carbohydrates, fats, and proteins that make up the body structures. The carbohydrates, fats, and proteins that animals eat do not get incorporated into body structures without first going through a chemical reaction.
Unlike plants, animals cannot link carbon atoms from carbon dioxide to make sugars or any other molecule made of linked carbon atoms.

Boundaries:

“Body structures” include any organ, tissue, or part of an organism with which students are likely to be familiar.
Students are not expected to know that muscles are made largely of protein molecules, fat tissue is made largely of fat molecules, or that the skeletons of insects, lobsters, and crabs are made largely of carbohydrate molecules.
Students are not expected to know the chemical or structural formulas of carbohydrates, proteins, or fats.
This idea does not include the synthesis of carbohydrates, fat, and proteins from their sub-units.
The idea that simple sugars are the “building blocks” of complex carbohydrates, that amino acids are the building blocks of proteins, and that fatty acids are the building blocks of fats are covered in Benchmark 6C/M2 (which is about digestion), not this key idea.
The idea that carbon, because of its small size and four available bonding electrons can join to several other carbon atoms in chains and rings to form large and complex molecules is part of Benchmark 5C/H8, not this key idea.
Students are not expected to know the identity of atoms other than carbon that are contributed by carbohydrates, fats, and proteins from food to the molecules that make up body structures.

Percent of students answering correctly (click on the item ID number to view the item and additional data)
Item ID Number	Knowledge Being Assessed	Pre-Test	Post-Test
SB021003	When a student eats a chicken sandwich, some of the proteins from the chicken meat go through chemical reactions to make new proteins that become part of the student’s body.	61%	86%
SB020002	When a wolf hunts and eats a deer, some of the deer meat goes through chemical reactions in the wolf’s digestive system and then becomes part of the wolf’s body.	52%	87%
SB017003	When a baby goose grows into an adult goose, the additional mass comes from the atoms that make up the food the baby goose eats.	52%	83%
SB049002	When a sea star regrows lost arms, most of the additional mass comes from atoms that made up the food the sea star ate.	30%	81%
SB014003	Aside from water, animal body structures are made up mostly of protein molecules.	29%	89%
SB063001	Animals build their body structures by digesting proteins in their food to amino acids and using the amino acids to build their body proteins.	22%	54%

Frequency of selecting a misconception
Misconception ID Number	Student Misconception	Pre-Test	Post-Test
SCM083	New atoms are created during chemical reactions (AAAS Project 2061, n.d.).	53%	11%
AMM070	Cells are not made up of atoms (Herrmann-Abell & DeBoer, 2008).	40%	2%
CEM020	Organisms grow by cell division, but the cells do not themselves increase in size or mass (AAAS Project 2061, n.d.).	32%	7%
MEM076	Food is simply converted into waste materials and eliminated from the body (Smith & Anderson, 1986).	15%	3%
MEM100	Food does not become part of the body. Instead food is used for energy, and the part that is not used for energy is eliminated as waste (AAAS Project 2061, n.d.).	14%	3%
SCM010	Matter can disappear with repeated division, dissolving, evaporation, or chemical change (Smith et al., 2004).	11%	5%
SCM085	Atoms can become heavier during a chemical reaction (AAAS Project 2061, n.d.).	10%	5%
BFM013	The carbohydrates, fats, and proteins from the food people eat are used by the body unchanged; they are not broken down into smaller molecules (AAAS Project 2061, n.d.).	7%	3%

Frequency of selecting a misconception was calculated by dividing the total number of times a misconception was chosen by the number of times it could have been chosen, averaged over the number of students answering the questions within this particular idea.

NGSS Statements
Code	Statement
LS1.C MS	Within individual organisms, food moves through a series of chemical reactions in which it is broken down and rearranged to form new molecules, to support growth, or to release energy.