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?

   • A glycosidic bond
   • No bond: the beads just touch
   • 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?

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

4. Use this

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

5. 3.

   Esme studies a chain. Glycerol bead A and fatty-acid bead B are joined by a covalent bond. What is that bond called?

   • An ester bond
   • A glycosidic bond
   • No bond: the beads just sit together
   • A peptide bond
6. 4.

   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
   • Hydrolysis: the beads join and water is used
   • Dehydration synthesis: the beads join and water is released
   • Dehydration synthesis: the beads join and water is used
7. 5.

   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
   • Hydrolysis: the chain splits and water is used
   • Neither: the chain splits with no water involved
   • Dehydration synthesis: the chain splits and water is released
8. 6.

   Building-block chain, not to scale. Luz watches a model of a glycerol bead and a fatty-acid bead linking up. One water bead floats away. What reaction is this?

   • Dehydration synthesis: the two beads link and one water is released
   • Dehydration synthesis: the two beads link and one water is used
   • Neither: the two beads link with no water involved
   • Hydrolysis: the two beads link and one water is used

9. 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.

10. 7.

    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?

    • 5 waters
    • 6 waters
    • 1 water
    • 4 waters
11. 8.

    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
12. 9.

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

    • Break pieces apart by adding water
    • Put pieces together while losing water
    • Put pieces together by adding water
    • Join pieces with no water involved
13. 10.

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

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