Colegio Real de Panamá 9th Grade Science: The Cell System

Write the letters of the correct answers on the lines at left. (1 point)

______ 1. Mad cow disease is caused by deformed proteins called prions. The disease is spread when meat from an infected cow is eaten. Prions can cause normal proteins to become deformed, producing more prions. After a few years, the brain of an infected person or cow looks like a sponge full of holes. Are prions considered organisms?A. Yes, because they can cause disease.B. Yes, because they can make more of themselves.C. No, because they are not made of cells.D. No, because they can’t make their own food.

______ 2. Before the invention of microscopes, scientists did not know about cells. Some thought that life just appeared out of nowhere. Microscopes allowed scientists such as Schleiden and Schwann to see organisms under high magnification. After much study, which ideas became parts of the cell theory? Choose the three statements that apply. (3 points)A. Cells contain specialized organelles.B. Cells are the basic units of life.C. A group of similar cells make up a tissue.D. All living things are made up of cells.E. All cells come from other cells.

Fill in the blank with a word to correctly complete the paragraph below. (2 points)

3. The ghost plant is white with a single stalk. Even though it looks more like a mushroom,

the ghost plant is related to blueberry plants. The ghost plant is a parasite that feeds on

fungi under the ground. Ghost plant cells have all the usual plant organelles except for a

_________________.

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______ 4. A virus can reproduce only inside a cell. Once inside, the virus causes the cell to make many new copies of the virus. In an animal, which part of the cell is responsible for keeping viruses out?A. cell membraneB. nucleusC. vacuoleD. cell wall

Name_________________________ Number: _____ Score: ___ / 46

Date: ____ /____/ 2020 Professor: Yiannis Gleglés

Circle the words or phrases that correctly complete the sentences. (2 points)

5. Immune cells in your body protect you from invading microorganisms. If the cells encounter

an invader, they consume it by the process of (diffusion / exocytosis / endocytosis / passive transport). After the invader is digested, waste materials are ejected from the cell

by (exocytosis / facilitated diffusion / endocytosis / osmosis).

6. In a cold climate, it takes a huge amount of energy to keep a mammal’s body warm all winter. Ground squirrels have found a way to reduce that energy cost. They find a safe burrow underground and go to sleep. They let their body temperature fall all the way below the freezing point of water! The ground squirrel’s brain is kept just a little warmer. (5 points)

Through the winter, the ground squirrel’s cells still carry out functions at a slow rate. Read each description of the cell processes for obtaining and removing materials. Use the graphic organizer to place each sentence in the correct column.

Water passes into cells through osmosis. • Cells take in large particles through endocytosis. • Carbon dioxide diffuses out of cells. • Larger molecules such as sugars move into cells by facilitated diffusion. • Cells move proteins out of the cell by exocytosis.

Active Transport Passive Transport

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______ 7. Dr. Rivera is a microbiologist at a research hospital. She studies bacteria with genetic changes that affect cell division. Dr. Rivera has discovered one change that stops the cell cycle between metaphase and anaphase. The change does not kill the cells, but it does prevent them from dividing. Why will these cells be unable to divide?A. They will be unable to replicate their genetic material.B. They will be unable to separate their chromosomes into chromatids

that will go to each daughter cell.C. They will be unable to grow large enough to reproduce.D. They will be unable to split into two daughter cells.

Fill in the blanks with words to correctly complete the paragraphs below. (3 points)

8. After you set up a fish tank, you are sure to see algae growing in it. There is plenty of

light, fertilizer in the form of fish droppings, and plants or glass for algae to cling to. You

may see green strings of algae in the water or green spots growing on the glass. Your

whole aquarium can turn green if you don’t stop the algae. To prevent the problem, you

can add algae-eating fish or microorganisms to the water. Covering the aquarium for a

few days will also kill algae, which need photosynthesis to survive. Multi-celled algae

grow into larger organisms through cell division. For one-celled algae, the purpose of cell

division is ___________________.

Use the information below to answer questions 9 and 10.

Beetles called ash borers lay their eggs under the bark of an ash tree. The baby beetles, called larvae, chew through the tree’s tough bark. Then the larvae feast on the softer, living cells of the inner bark. Inner bark transports carbohydrates and water between the tree’s parts. Without a working transportation system, the tree dies.

The only way to save an infested ash tree is to treat it with insect-killing chemicals. Killing the ash borer larvae stops the insects, but the damage remains. The wandering tunnels carved out by the ash borer larvae are shown in the illustration.

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______ 9. After an ash tree is treated to kill the beetles, how can the tree repair the damage from the larvae tunnels?A. Other kinds of cells could change to inner bark cells to repair the

tunnels.B. The cells around the tunnels could grow much larger to fill in the

tunnels.C. The tree could fill in the tunnels by sending cells from other parts of

the tree.D. The tree could replace the damaged tissues through cell division by

nearby cells.

10. The graph shows how long trees live after they are infested by ash borers. Use data from the graph to circle the best options to complete the sentence below. (2 points)

The fastest rate of tree death was between (1 / 9 / 13 / 5) and (3 / 8 / 15 / 12) years after the

trees were infested.

Use the information below to answer questions 11 and 12.

Susan has just moved into a new house. For some reason, she cannot get the grass to grow in her yard. She decides to grow small amounts of grass inside her house as part of an experiment. The first group of grass is exposed to a light intensity of 400. The second group is exposed to a light intensity of 1200. The graph below shows the results of Susan’s experiment.

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______ 11. According to the graph, which of the following should be expected from Susan’s two groups of plants?A. The plants at a light intensity of 1200 will produce more oxygen than

the plants at 400.B. The plants at a light intensity of 1200 will perform only stage 1 of

photosynthesis.C. The plants at a light intensity of 400 will produce more glucose than

the plants at 1200.D. The plants at a light intensity of 400 will grow more quickly than the

plants at 1200.

Write an answer for the following question in the space provided. (6 points)

12. Susan then goes outside to measure the light intensity that different parts of her yard receive. She notes that part of her lawn receives sunlight at an intensity of 250 and other parts receive sunlight at an intensity of 450. She decides that she will try two different things to get the grass to grow. First, she will try watering the grass more often. If that doesn’t work, she will increase the light getting to the grass by cutting down a few trees. Predict the results of each treatment and explain your answer.

13. Jake’s junior high science class is learning about photosynthesis and has decided to conduct an experiment. They are going to try to grow a garden with different types of plants to investigate the process of photosynthesis. There are two main steps in photosynthesis: Stage 1 and Stage 2. Write each sentence from the sentence bank in the correct box in the table. (4 points)

Sentence Bank:• Sunlight splits water molecules into hydrogen and oxygen. • Glucose, a type of sugar, is produced. • Oxygen is released into the environment. • Chlorophyll, the green pigment found in chloroplasts, is required.

Stage 1 Stage 2

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______ 14. Dimitri is measuring the amount of oxygen released by a Venus flytrap plant. He determines that his plant has released 600 molecules of oxygen (O2). If this is correct, how many molecules of glucose did the Venus flytrap create?A. 50B. 100C. 300D. 600

Use the information below to answer questions 5 and 6.

Alma is planning on joining the track team this year. In preparation for the season, Alma decides she wants to start running on her own to get in shape.

15. One day, Alma eats a granola bar and then runs a few quick laps around the track. How does her body obtain energy from food that will help her while exercising? Number the lines at left to place the following events in order based on what is happening in her body’s cells as she runs. (5 points)

_____ Oxygen is used to break down smaller molecules.

_____ A glucose molecule enters the body cell.

_____ A large amount of energy is released.

_____ Smaller molecules enter the mitochondrion.

_____ A glucose molecule is broken down in the cytoplasm.

Write an answer for the following question in the space provided. (6 points)

16. The next day, Alma decides to work on short sprints instead of long-distance running. Explain how Alma’s body cells would obtain energy differently when she sprints than when she runs long distances. When would her body’s cells make energy more efficiently? Why?

17. Circle the image that would release carbon dioxide as a waste product.

Write the letters of the correct answers on the lines at left. (1 point)

______ 18. Max has a group of goldfish in his tank at home. He notices that they are struggling a bit. Max wants to increase their rate of cellular respiration in hopes that it would help them to survive. Which of the following actions would potentially increase the rate of cellular respiration in the goldfish?A. Reducing the amount of food placed in the tank.B. Increasing the amount of carbon dioxide in the tank.C. Increasing the amount of oxygen in the tank.D. Reducing the amount of sunlight that hits the tank.