How small molecules join into big ones

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. Read this first

   Use this

   Building-block chain, not to scale. 2 amino-acid beads in a row, each neighbor pair joined by a covalent bond. Bead A is an amino-acid bead; bead B is an amino-acid bead.

2. 1.

   Ari studies a building-block chain. Two amino-acid beads, A and B, are joined by a covalent bond. What is that bond called?

   • No bond: the beads just touch
   • A glycosidic bond
   • A peptide bond
   • An ester bond
3. 2.

   Bo studies a chain. Two glucose beads, A and B, are joined by a covalent bond to make maltose. What is that bond called?

   • A glycosidic bond
   • An ester bond
   • A peptide bond
   • No bond: the two sugars just mix
4. 3.

   Building-block chain, not to scale. Jun watches a model of 3 amino-acid beads joining into one chain. A water bead floats off at each join. What reaction is this?

   • Neither: the beads join with no water involved
   • Dehydration synthesis: the beads join and water is released
   • Dehydration synthesis: the beads join and water is used
   • Hydrolysis: the beads join and water is used
5. 4.

   Building-block chain, not to scale. 3 water beads arrive, one at each bond. Kira watches a model of a 4-bead sugar chain being split apart. A water bead joins in at each bond. What reaction is this?

   • Hydrolysis: the chain splits and water is released
   • Dehydration synthesis: the chain splits and water is released
   • Neither: the chain splits with no water involved
   • Hydrolysis: the chain splits and water is used
6. 5.

   The released waters are not drawn. Milo builds a chain of 4 amino-acid beads. Each join released one water. Count the joins in the drawing. How many waters were released altogether?

   • 4 waters
   • 5 waters
   • 1 water
   • 3 waters

7. Use this

   Building-block chain, not to scale. 6 glucose beads in a row, each neighbor pair joined by a glycosidic bond. The released waters are not drawn.

8. 6.

   Noah builds a chain of 6 glucose beads. Each join released one water. Count the joins in the drawing. How many waters were released altogether?

   • 1 water
   • 4 waters
   • 6 waters
   • 5 waters
9. 7.

   The released waters are not drawn. Pia builds a short chain of 5 amino-acid beads. Each join released one water. Count the joins in the drawing. How many waters were released altogether?

   • 6 waters
   • 3 waters
   • 4 waters
   • 5 waters
10. 8.

    not to scale. Ren reads that a long chain of beads is called a polymer. What does the word polymer mean?

    • A water molecule that is released at a join
    • A covalent bond that links two neighboring beads
    • A single small building block, such as one amino acid
    • A chain of monomers joined by covalent bonds
11. 9.

    Tala sees the term dehydration synthesis on a card. Which meaning fits?

    • Put pieces together while losing water
    • Put pieces together by adding water
    • Break pieces apart by adding water
    • Join pieces with no water involved
12. 10.

    Zee sees the term hydrolysis on a card. Which meaning fits?

    • Break a chain apart by releasing water
    • Break a chain apart by adding water
    • Put pieces together while losing water
    • Break a chain apart with no water involved