Chapter 1 - Life Sciences 11

Practice questions for chapter 1 of Biology textbook. Includes multiple choice and written responses and basic vocabulary.

A scientific theory is

a. Another word for hypothesis.

b. A well-tested explanation that unifies a broad range of observations.

c. The same as the conclusion of an experiment.

d. The first step in a controlled experiment.

b. A well-tested explanation that unifies a broad range of observations.

The process in which two cells from different parents unite to produce the first cell of a new organism is called

a. Homeostasis

b. Development

c. Asexual reproduction

d. Sexual reproduction

d. Sexual reproduction

The process by which organisms keep their internal conditions relatively stable is called.

a. Metabolism

b. evolution

c. a genome

d. Homeostasis

d. Homeostasis

An instrument that produces images by focusing light rays is called a(an)

a. Light microscope

b. Transmission electron microscope

c. Scanning electron microscope

d. Electronic balance

a. Light microscope

What is the goal of science?

The goal of science is to investigate and understand the natural world to explain events and use those explanations to make inferences.

How does an observation about an object differ from an inference about that object?

An observation about an object is to gather data about it, while an inference is to make a logical explanation based on that data or prior experience.

How does a hypothesis help scientists understand the natural world?

A hypothesis helps scientists understand the natural world because it’s a possible scientific explanation for an event based on observations.

Why is it advantageous for scientists to test one variable at a time during an experiment?

Because testing one variable at a time allows scientists to make the experiment as accurate as possible. Testing more than one variable could affect the accuracy and results.

Distinguish between a variable and a control.

A variable is a factor in an experiment that changes, such as temperature, sunlight, age, time or amount of liquid. While a control is a factor that is controlled and observed to see the results.

What steps are involved in making a valid conclusion?

First, review your data and compare it to your hypothesis, does it support your hypothesis or not? Consider if external factors could’ve affected your result, if they are accurate others should be able to replicate the outcome. Based on these steps see if your hypothesis was correct, if so why?

What must happen for a hypothesis to become a theory?

In order for a hypothesis to become a theory, it must be so well-supported by data from multiple experiments that over time scientists see it as the most possible explanation.

How are unicellular and multicellular organisms alike? How are they different?

They are both similarly made up of cells and can carry out basic life functions like reproduction, growth and metabolism. A difference between them is that unicellular organisms are made up of a single cell, while multicellular organisms can be made up of thousands or even trillions of cells. Although unicellular organisms can only be produced through asexual reproduction, multicellular organisms can be produced through both sexual and asexual reproduction.

Distinguish between external and internal stimuli. Give an example of each.

External stimuli come from the environment outside of an organism, like temperature and light, while internal stimuli come from within the organism, like the glucose level in our bodies.

Science

An organized way of using evidence to learn about the natural world.

Observation

Gathering information about events in a careful, orderly way.

Data

Information gathered from observations.

Inference

A logical interpretation based on prior knowledge or experience.

Hypothesis

A proposed scientific explanation for a set of observations.

What does science study?

Science studies the natural world in a careful, orderly way using evidence (data) to explain natural events.

What does it mean to describe a scientist as skeptical? Why is skepticism considered a valuable quality in a scientist?

It means they question existing ideas & new hypotheses, because it allows them to evaluate the strengths and weaknesses of hypotheses & be open to consider new ones if enough data backs them.

Controlled experiment

An experiment where one variable is changed and all other variables remain unchanged.

Manipulated variable

Variable that is deliberately changed.

Responding variable

Response to the manipulated variable.

Theory

A well-tested explanation that unifies a broad range of observations.

How does a scientific theory compare to a scientific hypothesis?

A scientific theory is a hypothesis that is so well supported by the evidence from many experiments that it becomes the accepted explanation.

Biology

The science that seeks to understand the living world.

Cell

A collection of living matter enclosed by a barrier that separates the cell from its surroundings.

Sexual reproduction

When cells from two different parents unite to produce the first cell of a new organism.

Asexual reproduction

A single cell or organism makes a copy of itself (one parent).

Metabolism

A combination of chemical reactions through which an organism builds up or breaks down materials as it carries out its life processes.

Stimulus

A signal to which an organism responds.

Homeostasis

The process by which organisms must keep their internal conditions (temperature, water content, etc.) constant to survive.

Evolution

The ability of a group of organisms to change over time to survive in an ever-changing world.

What are some characteristics of living things?

They grow, reproduce, need energy, are made up of cells, are based on a universal genetic code, maintain a stable internal environment, respond to their environment, obtain their food (energy), and change over time as a group.

Metric system

Decimal system of measurement, whose units are based on certain physical standards and are scaled on multiples of ten.

Microscope

Device that produces magnified images of structures that are too small to see with the unaided eye.

Light microscope

Focuses on the visible light rays. Can study dead organisms and tiny alive ones.

Electron microscope

Produces magnified images using beams of electrons. It cannot be used to observe living organisms.

Cell culture

A group of cells.

Cell fractionation

A technique to separate the different cell parts.

What is the process of cell fractionation?

The cell is broken into pieces in a special blender, broken cell bits are added to a liquid and put into a tube, the tube is inserted into a centrifuge (to spin it), cells parts separate from the spinning (dense parts at the bottom), biologist removes the part they need.

Why do scientists use a common system of measurement?

Because they replicate each other’s experiments which most of the time involve measurements.

What types of objects can be studied with a light microscope? What types can be studied with an electron microscope?

You can study dead or living organisms with a light microscope & only dead organisms with an electron microscope.

What is the purpose of cell fractionation?

The purpose is to separate cell parts to study them separately.