Join with water out, split with water in

Science · Organisms & Life Processes · ages 16-17

Name ______________________ Date ____________

What does hydrolysis spend to break one bond open?
- One water molecule
- One amino acid
- One burst of light
What does a condensation reaction release when one bond forms?
- One molecule of water
- One molecule of oxygen
- One molecule of carbon dioxide
Digestion uses hydrolysis to chop starch and protein into pieces small enough to absorb.
Circle one: True False
A chain of 12 monomers formed by condensation. How many water molecules were released?
Answer: ______________
Starch is a carbohydrate. Which bond holds its sugars together?
- A peptide bond
- A phosphodiester bond
- A glycosidic bond
A chain of 100 pieces must be broken fully apart by hydrolysis. How many water molecules are needed?
Answer: ______________
Your gut digests DNA back into nucleotides. Which bond does hydrolysis snap?
- A glycosidic bond
- A peptide bond
- A phosphodiester bond
A student says a 20 monomer chain released 20 waters when it formed. What is wrong?
- Water is never released by joining
- Chains release 19 waters, since links number one fewer than pieces
- Only proteins release water when joining

Answer key

For grown-ups. Fold this page away before handing over the rest.

One water molecule · Breaking is the reverse of joining, costing one water per bond.
One molecule of water · Every joining releases exactly one water as the bond forms.
True · Your gut spends water to snap food polymers back into pieces.
11 · Twelve pieces mean 11 links, and each link released one water.
A glycosidic bond · Sugars always team with glycosidic bonds.
99 · Breaking 99 links spends 99 waters, one per bond.
A phosphodiester bond · Nucleotides always team with phosphodiester bonds, joined or split.
Chains release 19 waters, since links number one fewer than pieces · Twenty pieces share 19 links, so only 19 waters left.