A group of 4 students want to design an experiment in an effort to support the hypothesis, “Sunlight is needed for the normal healthy growth of plants.” Each student presented a possible experiment.

Student #1: Purchase 20 plants. Plant 10 of the plants in 3 cups of soil and place all of the cups in the sun. Take the other 10 plants and put them in 2 cups of soil, then place this group in the sun under a box. Observe and document changes.

Student #2: Place 10 plants outside in the sunlight. Place the other 10 plants outside under a box. Plant both in the same amount of soil and provide all with the same amount of water. Document observations.

Student #3: Place 20 plants in front of a window. Give all of the plants the same amount of water and the same type of soil. Observe plants for any changes.

Student #4: Obtain two seeds. Place one seed outside and one on an inside window sill. Observe and document which seed sprouts the fastest.

Which student provides the best reason for choosing his or her experiment to test the hypothesis?

• Student #1:“The plants will react differently in different amounts of soil”

• Student #2: “Included are 10 plants that were not placed in the sun.”

• Student #3: “All of the plants were placed in the sun and kept under the same conditions.”

• 1. Student #4: “Seeds grow into plants, so if the seeds are healthy, then the plants will also be

  healthy.”

Tags

NGSS.HS-LS1-5

NGSS.HS-LS2-5

Enzymes are proteins which increase the rate of chemical reactions. The graph below represents data collected during an experiment comparing how temperature effects the enzymes amylase and protease.

Based on this experiment, which of the following could be inferred about enzymes?

• The temperature at which enzymes are the most active is different for each enzyme.

• Total enzyme activity always decreases and increases at the same time.

• Enzyme activity is always greater the hotter the temperature.

• Enzymes are never reactive at low temperatures.

Directions: Identify the choice that best completes the statement or answers the questions.

Using the illustrations above, which of the following correctly identifies the molecules shown?

• F. Carbohydrate

  G. Lipid

  H. Nucleic Acid

  I. Protein

• F. Nucleic Acid

  G. Carbohydrate

  H. Lipid

  I. Protein

• F. Lipid

  G. Protein

  H. Carbohydrate

  I. Nucleic Acid

• F. Protein

  G. Nucleic Acid

  H. Carbohydrate

  I. Lipid

In all organisms, there are certain molecules that have functions necessary for life’s processes. Which of the following is a function of both lipids and carbohydrates?

• Both are sources of energy

• Both are monomers in molecules which determine the genetic makeup of organisms

• Both can be found in a variety of shapes and formations that enable them to carry oxygen.

• Both have hydrophobic and hydrophilic ends and are responsible for moving materials in

  and out of a cell through the cell membrane.

All of the biological macromolecules found in organisms contain hydrogen, oxygen and carbon. However, there are distinguishing features of each. Which of the following could be used to differentiate between a carbohydrate and a nucleic acid?

• Carbohydrate molecules have a nitrogen base, whereas, nucleic acid molecules have an R group.

• Carbohydrate molecules have nitrogen atoms, whereas, a nucleic acids have an attached phosphate group.

• Carbohydrate molecules are only found in rings, while nucleic acid molecules form ring or branched chain shapes.

• Carbohydrate molecules contain only carbon, hydrogen and oxygen atoms, whereas, nucleic acid molecules also have a nitrogen base and phosphate group.

During a class experiment, Wendy investigates the rates of catalyzed reactions at different temperatures. Which statement is a valid hypothesis for her experiment?

• Each enzyme has an optimal temperature at which it catalyzes a reaction.

• Enzymes always catalyze reactions at the same rate and are not affected by temperature.

• Enzymes catalyze all reactions at the same rate, no matter the environmental conditions.

• Enzymes act upon too many different molecules to run this test; the data would be

  inconclusive.

Tags

NGSS.HS-PS1-5

What will happen to the rate of enzyme activity if substrate is continuously added to a fixed amount of enzyme while also being kept at an optimal temperature and pH?

• Increase, then decrease

• Decrease, then increase

• Increase, then remain constant

• Decrease, then remain constant

Ice fishermen drill holes in ice covered lakes so they can fish in the cold winter months. The water beneath the layer of ice remains liquid. If the ice sank to the bottom, the lake would freeze from the bottom to the surface. This would freeze all of the lake’s organism. Which property of water explains this occurrence?

• The bonds, between the water atoms, break expanding the ice molecules so that liquid

  water can fill the spaces in between the frozen water molecules.

• The hydrogen bonds of water expand during the freezing process, creating more volume

  and decreasing density of the ice.

• The water’s cohesive properties keeps the molecules close together, therefore, increasing

  the density ice.

• A lower pH makes the water more acidic, resulting in the neutral ice floating.

The picture shows a group of water skate bugs “walking” on the surface of a pond. When an insect lands or falls into the water, the water molecules vibrate. The water skater uses the resulting vibrations to find its prey. What property of water enables this bug to stay on the surface of the pond and not sink?

• Water’s high specific heat enhances the vibrations causing the bugs to float.

• An optimum pH of the pond water, keeps the water calm so that the bugs don’t sink.

• The hydrogen atoms, in the water, bond to the bugs’ legs keeping the bugs on the surface.

• Hydrogen bonds provide cohesion of the water molecules enabling the bugs to stay afloat.

Tags

NGSS.HS-ESS2-5

Sophia produces the graph, shown below, during a biology class investigation.

What could she infer about the probable difference between the original reaction and Reaction B based on the data?

• An enzyme was added to Reaction B.

• More substrate was added to Reaction B.

• Additional water was added to Reaction B.

• Additional reactants were added to Reaction B.