1. Keystone Review #1 - The Nature of Science

The bacterium Acetobacter aceti is found in acidic environments and has an acidic cytoplasm. For this reason, most of its proteins are able to function in acidic conditions. This property distinguishes Acetobacter aceti proteins from those of most other organisms. Which characteristic does Acetobacter aceti most likely share with other organisms?

• the method that the organism uses to reproduce itself

• the physical and chemical responses to environmental changes

• the type of organelle used to produce energy for cellular functions

• the process used to form proteins by transcription and translation

Statement 1: All living things are composed of cells.

Statement 2: If soil contains high levels of salt, the plants will die.

Statement 3: The temperature reading on the thermometer is 21°C.

Statement 4: It must have rained this morning because the soil is wet.

A teacher lists four statements for students to interpret. Which table of information correctly distinguishes between the statements?

• Statement 1 - Theory Statement 2 - Hypothesis

  Statement 3 - Observation Statement 4 - Inference

• Statement 1 - Fact Statement 2 - Theory

  Statement 3 - Hypothesis Statement 4 - Observation

• Statement 1 - Inference Statement 2 - Observation

  Statement 3 - Theory Statement 4 - Fact

• Statement 1 - Observation Statement 2 - Inference

  Statement 3 - Fact Statement 4 - Hypothesis

Life functions are performed at many levels of biological organization. Which level of biological organization is the simplest level at which a structure can support life functions?

• cell

• tissue

• organelle

• organ system

Quantitative Observations

37 fish and 3 frogs, 2 types of aquatic grass, 12 small rocks and 1 medium rock, sand

Qualitative Observations

Leaves lie on the bottom of the pond, Water insects move along the water’s surface, All 3 frogs are sitting on a pond bank.

A group of students measured a ten-square-meter section of a pond ecosystem and recorded observations. Which statement is a testable hypothesis?

• The frogs living in the pond represent a population.

• Water is an abiotic component in the pond ecosystem.

• If the fish are given more food, then they will be happier.

• If the frogs are startled, then they will jump into the water

Which characteristic of life is best shown by this diagram?

• DNA is the genetic code in an organism.

• An organism is made of one or more cells.

• An organism responds to changes in its environment.

• Changes occur in an organism as it grows and develops.

Which statement is a hypothesis?

• The presence of an enzyme increased the reaction rate.

• The reaction rate increased 100% once the enzyme was introduced.

• Introducing an enzyme into a reaction did not increase the rate of the reaction.

• When an enzyme is introduced into a reaction the reaction rate will increase by 100%.