Scientific Process

1. Scientific Process 1. Students hypothesized that water pollution affects the growth of fish. In an experiment, they added the same amount of food to ponds polluted by fertilizers and industrial waste. They measured fish growth and found that most fish grow slowly in each of these environments. Why is their conclusion not reliable? A. They did not have a control B. They did not have a clear hypothesis. C. They only tested one independent variable. D. They did not have a dependent variable.

2. Scientific Process 2. A student hypothesized that watching sports on television would cause viewers’ pulse rates to increase. She designed an experiment to determine the effect of watching sports on pulse rate. A group of 200 volunteers took their pulse rates and then watched their favorite sports on television. After the games, they immediately took their pulse rates again. The data collected showed that the pulse rates of some people increased, but the pulse rates of an equal number of people did not change. Although the hypothesis was not supported by the data, the hypothesis is still valuable because it A. may lead to further investigation B. can be changed to fit the data C. is the opinion of the experimenter D. is based on beliefs of the volunteers

3. Scientific Process 3. Students were asked to design a lab that investigated the relationship between exercise and heart rate. Heart rate was determined by recording the pulse rate in beats per minute. The students hypothesized that increased exercise results in an increased heart rate. The class results for the experiment are shown in the graph below. Which statement is best supported by the graph? • Before exercising, the average pulse rate was 65; four minutes after exercising, the average pulse rate was 65. • After four minutes of exercising, the average pulse rate was 120; two minutes after exercising, the average pulse rate was 120. • While exercising, the highest average pulse rate was 150; before exercising, the average pulse rate was 65. • Two minutes before exercising, the average pulse rate was 80; after two minutes of exercise, the average pulse rate was 140.

4. Scientific Process 4. Students in a different science class carried out the same experiment. The data they obtained did not support the hypothesis that increased exercise results in increased heart rate. The most scientifically sound way to deal with this situation is to • write a new hypothesis • read about pulse rate in a biology textbook • have the students in both classes vote to decide which hypothesis is correct • ask students in a third class to do the experiment and see if their results support the hypothesis

5. Scientific Process 5. At which stage of scientific thinking are scientists most likely to consider the data and conclusions of other scientists to propose new experiments? a. observing b. testing hypotheses c. analyzing data d. forming hypotheses

6. Cell Processes 6. What type of organism might contain the cell shown above? • Alga • Animal • Bacterium • Plant

7. Cell Processes 7. Cells may have different shapes and different numbers of organelles, depending on their function. Which features do plant cells have that animal cells lack? • chloroplast, ribosome, and cell wall • Golgi apparatus, cytoskeleton, and vesicle • Cell wall, chloroplast, and central vacuole • Central vacuole, chloroplast, and smooth ER

8. Cell Processes 8. Which of these statements best explains the process of energy conversion that takes place in the mitochondria? F. Energy is required for carbon dioxide molecules to form six-carbon sugar molecules. G. Water molecules and radiant energy are necessary for anaerobic respiration to take place. H. Oxygen molecules release energy in the form of heat during combustion reactions. J. The energy in the bonds of glucose molecules is transferred to the phosphate bonds in ATP.

9. Cell Processes 9. The illustration above shows a cell and a large particle. Many substances, such as proteins and polysaccharides, are too large to be transported into a cell by carrier proteins. In a process called endocytosis, the large particle is brought into the cell. Which of the following statements correctly summarizes this process? A. Waste materials carry the particle into the cell. B. The particle passes directly through a protein doorway in the cell membrane. C. The particle passes directly through the phospholipids that make up the cell membrane. D. The cell membrane surrounds the particle and forms a vesicle that is brought into the cell.

10. Cell Processes 10. Some levels of organization in a multicellular organism are shown in the sequence below: A → cells → tissues → B → organ systems → organism Which terms represented by letters A and B would complete the sequence? A. A–gametes; B–zygote C. A–organs; B–organelles B. A–zygote; B–gametes D. A–organelles; B–organs

11. Cell Processes 11. In order for the human body to maintain homeostasis, the breakdown of glucose to release energy must be followed by the A. production of oxygen B. division of the cell C. removal of wastes D. production of receptor molecules

12. Cell Process 12. A single-celled organism has organelles called contractile vacuoles to move water from inside to outside the cell. The data presented in the table above were obtained in an experiment in which an organism was placed in water with different salt concentrations. The rate at which the contractile vacuole contracted to pump out excess water was recorded. How could you explain the observed relationship between the rate of contractile vacuole contractions and the salt concentration? A. When the salt concentration outside the cell is very high, diffusion causes water to move inside the cell, and the contractile vacuole has to contract more rapidly. B. When the salt concentration outside the cell is very low, diffusion causes water to move outside the cell, but it has no impact on the contractile vacuole contractions. C. When the salt concentration outside the cell is very high, diffusion causes water to move outside the cell, and the contractile vacuole does not need to contract as rapidly. D. When the salt concentration outside the cell is very low, diffusion causes water to move outside the cell, and the contractile vacuole does not need to contract as rapidly.

13. Cell Processes 13. The diffusion of water through a selectively permeable membrane is called osmosis. Which description represents the effects of osmosis on a plant cell when the concentration of sugar particles is greater inside the cell than outside? A. Water diffuses into the cell, and the cell swells. B. Water diffuses out of the cell, and the cell shrinks. C. Water moves into and out of the cell at equal rates, and cell size remains the same. D. Water is blocked from moving into or out of the cell, and cell size remains the same.

14. Cell Processes 14. Some processes that occur in a cell are listed below. A. utilize energy B. detect changes in the environment C. rearrange and synthesize chemical compounds Which processes will all living organisms use to maintain homeostasis? (A) A and B, only (B) B and C, only (C) C and A, only (D) A, B, and C

15. Cell Processes 15. Which cellular process takes place in the ribosomes that are bound to the endoplasmic reticulum? A The breakdown of waste material B The conversion of radiant energy to glucose C The synthesis of new proteins D The replication of nucleic acids

16. Organic Compounds 16. Enzymes are proteins that help increase the rate of chemical reactions inside cells. These proteins are composed of many simpler molecules called amino acids. Which of the following suggests that the shape of an enzyme determines the enzyme’s function? F. Enzymes are specific to a substrate. G. Enzymes can operate in a wide range of conditions. H. Enzymes are activated by neighboring molecules. J. Enzymes can be found in all life-forms.

17. Organic Compounds 17. Proteins and polysaccharides are polymers. These polymers are formed by dehydration synthesis. Which statement correctly identifies a difference in the structure of proteins and polysaccharides? F Only polysaccharides are comprised of repeating units of cytosine, adenine, guanine, and thymine. G Only proteins are formed from amino acids joined by peptide bonds. H Only polysaccharides can be folded and twisted to very specific shapes. J Only proteins can be large molecules with thousands of subunits.

18. Organic Compounds 18. Which of these best represents a fatty acid molecule?

19. Organic Compounds 19.Which group contains larger molecules that are each assembled from smaller organic compounds? A. Proteins, water, DNA, fats B. Proteins, starch, carbon dioxide, water C. Proteins, DNA, fats, starch D. Proteins, carbon dioxide, DNA, starch

20. Organic Compounds 20. Based on the results of a series of experiments, Joshua created the table to summarize some of the characteristics of the chemicals needed for life. From this information, it can be inferred that nucleic acids ___. A. are larger molecules than proteins. B. are necessary for a cell to make proteins from amino acids. C. do not mix with water. D. can be used by cells as an energy source.

21. Organic Compounds 21. What term best completes this analogy? Nucleotide is to nucleic acid as ______ is to protein. • DNA • Glycerol • Amino acid • Carbohydrate

22. Organic Compounds 22. Which structural formula represents a polysaccharide? A. 1 B. 2 C.4 D. 5

23. Organic Compounds 23. The diagram above illustrates the structure of glucose. Which of the following describes how the body uses molecules like the one illustrated above? A Sugars form carbohydrates, which are linked together to form fats that store energy. B Carbohydrates are broken down into glucose, which is stored inside the body’s cells. C Sugars are broken down into proteins that become the building blocks of the body’s tissues. D Carbohydrates, such as glucose, are broken down to release chemical energy that is used by the body’s cells.

24. Organic Compounds 24. Two of the four principle classes of organic compounds are proteins and nucleic acids. What is the relationship between proteins and nucleic acids? A. Nucleic acids use proteins for energy. B. Nucleic acids are a subset of proteins. C. Proteins are long polymers of nucleic acids. D. Nucleic acids contain the information to make proteins.

25. Organic Compounds 25. Hemoglobin, insulin, and maltase are polymers of amino acids. These are examples of – a. Proteins b. Carbohydrates c. Lipids d. Nucleic acids