How cell parts work together to make and ship a protein

Grade 9 Science Worksheet

Circle the best answer.

1. Read this first

   Use this

   Cell cutaway (animal cell, model, not to scale).

2. 1.

   Ari's class studies a gland cell that releases a digestive enzyme, a protein. Letter C, the Golgi apparatus, stops working. What most likely happens to the enzyme?

   • It is held up at the plasma membrane, because the Golgi comes last
   • No enzyme is made, because the Golgi apparatus builds the protein
   • It still leaves the cell, because each part works alone
   • It is made and folded but not packaged, so it stays in the cell
3. 2.

   Esme reads that vesicle C can no longer bud from the rough ER, letter B. Where does a new protein most likely pile up?

   • In the rough ER, because nothing carries it to the Golgi apparatus
   • In the Golgi, because the Golgi builds a new copy of the protein
   • In the Golgi anyway, because the Golgi works alone to collect it
   • In the Golgi anyway, because a vesicle is a permanent pipe between them

4. Use the table

   Pulse-chase card, read about only: a teacher added labeled amino acids to a gland cell for a short time, then followed the label. Where the labeled enzyme is found (model data)

   minutes after labeling	most label found in
   3	rough ER
   12	transport vesicles
   25	Golgi apparatus
   40	secretory vesicles
   60	outside the cell

5. 3.

   Jun reads a pulse-chase card. The label is in the Golgi apparatus at 25 minutes. Where is it found next, and why?

   • In transport vesicles, which stay fixed beside the Golgi apparatus
   • In the Golgi still, because the Golgi builds more protein from the label
   • Back in the rough ER, because the Golgi sends proteins back to be built
   • In secretory vesicles, because the Golgi packages proteins for shipping
6. 4.

   Pulse-chase card, read about only: a teacher followed a labeled membrane protein through a cell. Kira reads a card for a membrane protein. At 45 minutes the label is in the plasma membrane. What carried it there?

   • A transport vesicle from the rough ER, skipping the Golgi apparatus
   • The nucleus, which sent the finished protein straight there
   • A secretory vesicle from the Golgi that fused with the membrane
   • A permanent pipe running from the rough ER to the membrane

7. Use the table

   Pulse-chase card, read about only. Share of the label in each place (model data)

   minutes after labeling	rough ER (%)	Golgi apparatus (%)	outside the cell (%)
   5	80	15	5
   20	30	55	15
   40	10	25	65

8. 5.

   Luz reads the card. Which statement about the label is best supported by the table?

   • The Golgi built the label, because its share is largest at 20 minutes
   • Each part works alone, because the shares in each row add up to 100
   • It moves from outside to the Golgi to the rough ER, because outside is largest at 40 minutes
   • It moves from the rough ER to the Golgi to outside, so parts pass it along

9. Parts counted in one slice of each cell (model data)

   cell	rough ER sacs	mitochondria
   P	48	12
   Q	9	85

10. 6.

    Milo reads counts for two cells. One is from a salivary gland and releases a digestive enzyme. The other is a muscle cell. Which pairing do the counts support?

    • P is the gland cell, since secreting cells have abundant rough ER
    • Cannot tell, because each part works alone, so counts do not follow the job
    • Q is the gland cell, because cells that secrete proteins have many mitochondria
    • P is the gland cell, because mitochondria build the digestive enzyme
11. 7.

    Noah reads that cell X is a pancreas cell that makes digestive enzymes, which are proteins. Cell Y makes little protein. Which statement fits the counts?

    • Y has more ribosomes, because cells that make little protein need more
    • X has more ribosomes and more nuclei to build the extra protein
    • X has more ribosomes, yet the Golgi apparatus is what builds the protein
    • X has far more ribosomes, as cells making much protein need them
12. 8.

    Ren asks how the rough ER (A) and the Golgi apparatus (C) work together on a protein that leaves the cell. Which statement is right?

    • The rough ER makes and folds it, then a vesicle hands it to the Golgi
    • A permanent pipe joins the two parts, and the protein slides through it
    • The Golgi builds the protein first, then the rough ER packages it for release
    • Each part works alone: the Golgi builds its own second copy of the protein
13. 9.

    Cell cutaway (plant cell, model, not to scale). Part A makes sugar by photosynthesis. Tala studies a plant cell. Part A makes sugar by photosynthesis. How does part B, the bean-shaped part, use that sugar?

    • B uses the sugar in cellular respiration to provide ATP energy
    • B packages the sugar into vesicles, as the Golgi apparatus does
    • B makes the sugar that A uses for photosynthesis
    • B makes its own sugar, so it does not use the sugar from A

14. Use this

    Cell cutaway (animal cell, model, not to scale). The route has 7 stations, numbered 1 to 7, joined by arrows. Letter A marks the large round body near the middle, with a double wall (station 1). Letter B marks a small gap in the wall of the large round body (station 2). Letter C marks the flat folded sacs studded with tiny dots, joined to the wall of the large round body (station 3).

15. 10.

    Zee asks what the ribosomes on the rough ER (C) need from the nucleus (A) before they can build a protein. What is it?

    • The finished protein, which A builds inside and passes out through B
    • Nothing, since the rough ER builds proteins without any help from A
    • mRNA, which leaves A through B with the message for the protein
    • A packaged protein sent over from the Golgi apparatus