Vocabulary
True or False: Starch can pass directly into cells without being broken down.
false
The body system that brings oxygen into the body and removes carbon dioxide.
respiratory system
The body system that breaks down food into smaller molecules so they can be absorbed and used by cells.
digestive system
The body system that transports oxygen, nutrients, and wastes throughout the body using blood, the heart, and blood vessels.
The building blocks of proteins; small molecules that combine to make larger protein molecules.
amino acids
A thin, flexible barrier around the cell that controls what enters and exits.
cell membrane
Tiny air sacs in the lungs where gas exchange occurs (oxygen enters the blood, carbon dioxide leaves).
alveoli
Tiny fingerlike projections in the small intestine that absorb nutrients into the bloodstream.
villi
Which two systems provide the molecules that the circulatory system delivers to cells?
Digestive system and respiratory system.
A large carbohydrate made of many glucose molecules bonded together; found in foods like bread, rice, and potatoes.
starch
The sum of all chemical reactions in an organism, including breaking down food for energy and building new molecules.
True or False: Oxygen is broken down into smaller molecules before entering the bloodstream.
false
Which molecules need to be broken down before reaching the cell
protein and starch
What structure must glucose and oxygen cross before entering a cell?
cell membrane
A large molecule made of amino acids; important for structure, enzymes, and body functions.
protein
What structure in the lungs allows oxygen to pass into the blood?
Alveoli
What molecule do humans exhale as waste?
carbon dioxide (CO2)
What two systems do amino acids pass through before reaching the cell?
Digestive system → circulatory system.
Which organ pumps blood throughout the body?
heart
A gas taken in by the respiratory system; needed by cells to release energy from glucose during cellular respiration.
oxygen
A group of atoms bonded together; the smallest unit of a compound that retains its properties.
molecule
What is the main function of the respiratory system?
To bring oxygen into the body and remove carbon dioxide.
Which organ produces enzymes that help break down starch into glucose?
pancreas
What is the main function of the circulatory system?
To transport molecules (nutrients, oxygen) and wastes throughout the body.
A simple sugar (carbohydrate) that cells use as their main source of energy.
glucose