Science Assessment ~ Ideas ~ Within cells, energy is extracted from food and the molecules needed to build body structures are assembled.

Key Idea: Oxygen, carbon dioxide, and molecules from food are carried to or from cells of the body by means of the circulatory system.

Sub-Ideas
Items & Student Performance
Misconceptions
NGSS

Students are expected to know that:

The circulatory system is made up of a variety of blood vessels, which carry blood throughout the body.
Blood stays within a system of blood vessels: arteries, veins, and microscopically small blood vessels called capillaries.
Larger diameter blood vessels branch into progressively smaller blood vessels and eventually into microscopically small blood vessels known as capillaries.
Blood carries needed molecules (e.g., simple sugars, amino acids, fatty acids, and oxygen) to cells of the body and carries carbon dioxide and other waste molecules away from cells of the body.
Small molecules such as amino acids, simple sugars, fatty acids, oxygen, and carbon dioxide (but not large molecules like proteins, complex carbohydrates, and fat molecules) can cross the capillary walls.
Small molecules can pass through capillary walls but not through the walls of other blood vessels.
Capillaries are spread out throughout the entire body (and are in very close proximity to each of the cells of the body) so that needed molecules can get to the cells and waste materials can be removed from the cells.
All cells receive molecules from food by way of the circulatory system.

Boundaries:

The terms capillaries, veins, and arteries will be defined for students when they are used in the items.
Students are not expected to know the names of waste molecules other than carbon dioxide.
Students are not expected to know that white blood cells can pass (by squeezing) through capillary walls.
Students are not expected to know the names or functions of the components of blood (e.g., red blood cells, white blood cells, plasma).

Percent of students answering correctly (click on the item ID number to view the item and additional data)
Item ID Number	Knowledge Being Assessed	Grades 6–8	Grades 9–12
BF051004	Blood carries oxygen to cells and carries carbon dioxide away from cells.	56%	64%
BF135001	Blood stays within blood vessels and moves to all parts of the body.	51%	58%
BF122003	Blood stays within blood vessels and moves to all parts of the body.	49%	56%
BF075004	Blood carries both oxygen molecules and simple sugar molecules to cells of your leg muscles.	46%	58%
BF134001	Molecules from food and molecules of oxygen are carried by a network of arteries, veins, and microscopically small blood vessels (capillaries) to the rest of the body.	46%	56%
BF018005	Small molecules like amino acids can pass through capillary walls but large molecules like proteins cannot.	42%	55%
BF136001	Small molecules like amino acids can pass through capillary walls, but large molecules like proteins cannot.	43%	47%
BF016005	Oxygen is carried by blood to cells of the body, but carbon dioxide is not carried by the blood to cells of the body.	41%	48%
BF095004	Capillaries are found in body organs such as the brain, lungs, and intestines, and capillaries are also found inside external parts of the body such as arms, legs, hands, and feet.	35%	40%
BF056006	Capillaries allow small molecules like amino acids to pass through their walls but not large molecules like proteins. Molecules do not pass through the walls of large blood vessels.	35%	38%
BF144002	Molecules from food travel from the mouth to the digestive tract and then travel through a series of blood vessels to the cells in the rest of the body.	31%	39%
BF057007	Molecules pass through the walls of microscopically small blood vessels but not through the walls of large blood vessels.	28%	30%
BF126001	Neither large molecules like proteins nor small molecules like amino acids can pass through the walls of arteries and veins.	14%	14%

Frequency of selecting a misconception
Misconception ID Number	Student Misconception	Grades 6–8	Grades 9–12
BFM040	Air is distributed through the body in air tubes (Arnaudin & Mintzes, 1985; Catherall, 1982).	46%	39%
BFM031	Molecules from food are distributed by way of special tubes, not by way of the circulatory system, to the rest of the body (Catherall, 1982).	43%	38%
BFM070	Blood does not carry simple sugar molecules to the cells of the body.	38%	31%
BFM065	Blood flows freely through the walls of blood vessels.	35%	33%
BFM010	Carbon dioxide, oxygen, water, and molecules from food pass directly through the walls of arteries and veins to and from other parts of the body rather than through the walls of the capillaries (Minstrell, 2005).	32%	33%
BFM057	Capillaries are found only in internal organs, such as the lungs and the intestines (AAAS Project 2061, n.d.).	30%	28%
BFM051	Anything can pass through the walls of capillaries (AAAS Project 2061, n.d.).	25%	22%
BFM056	Capillaries are found only in the extremities, such as the hands and feet (AAAS Project 2061, n.d.).	23%	23%
BFM053	Blood does not carry oxygen to the cells of the body (AAAS Project 2061, n.d.).	25%	17%
BFM050	Nothing can pass through the walls of capillaries (AAAS Project 2061, n.d.).	12%	13%
BFM064	Molecules from food move directly from the mouth to the rest of the body without going through any kind of tubes.	8%	5%
BFM063	Molecules of oxygen move directly from the mouth and nose to the rest of the body without going through any kind of tubes.	8%	5%
BFM027	Food is free in the body (no links to digestive structures) (Carvalho et al., 2004).	8%	5%

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.A MS	In multicellular organisms, the body is a system of multiple interacting subsystems. These subsystems are groups of cells that work together to form tissues and organs that are specialized for particular body functions.