Overview

Science is very much a part of your everyday life. Whether you consider the basic electrical bulb or cutting-edge developments in agriculture and medicine, you soon realize that science is all around you. This course discusses the various areas of science, such as life science, physical science, and earth science. Examining scientific facts and developments will enable you to explore the role that science plays in your life and your environment.

The course components that enable you to achieve this goal include the textbook Pacemaker's General Science (3rd edition), published by Globe Fearon, and this study guide. The study guide, developed by the staff and faculty of The Hadley School for the Blind, guides you through the course.

Study guides are popular tools for completing distance education courses. This study guide introduces the material presented in the textbook and offers specific directions for completing each chapter. It provides answers to select review exercises. It also presents Enrichment Activities to replace the Lab Activities featured in the textbook.

This course is divided into seven units. Unit 1 introduces some of the wonders and practical aspects of science. Units 2 and 3 examine different facets of life science. Units 4 and 5 focus on physical science. Units 6 and 7 discuss earth science. Note that the textbook features a Glossary and several appendixes, all of which are optional material.

To complete each chapter, follow the instructions and complete only the activities specified in the study guidelines. As you complete the selected exercises, keep the following in mind:

  • Note your answers in the medium of your choice so you can compare them with those provided in the study guide.
  • Do not send answers to review exercises to your Hadley instructor.
  • If necessary, contact your instructor to clarify concepts.

You are required to submit all the assignments presented in the study guide. They enable your instructor to evaluate your progress throughout the course.

Chapter 4: Cells and Life

The previous chapter gave you some insight into the study of life. You probably have questions about living things themselves. How are they put together, and how do they work? Chapter 4 studies the cell, which is the basic unit of life, as explained in Lesson 4.1. It relates how Robert Hooke discovered the cell, and it compares cells to atoms, molecules, and elements. Lesson 4.2 describes the parts of the cell and how they work together. It contrasts plant and animal cells, and it discusses DNA. Examining the relationship between cells and life can help you explore the role that science plays in your life and your environment.

Study Guidelines

To complete this chapter, use your textbook and do the following:

1.Read pages 48 through 61.

2.Complete the lesson reviews on pages 52 and 57.

3.Skip the Lab Activity on page 58, as it is optional.

4.Complete the Vocabulary Review and Chapter Quiz on pages 60 and 61. (Note that the Research Project is optional.)

When you are finished, return to the study guide to do the following:

5.Compare your answers.

6.Do the Enrichment Activity.

7.Complete the assignment.

Lesson Reviews

Answers for Page 52

1.Robert Hooke saw plant cells through his microscope.

2.Molecules are made of atoms that are chemically bonded to one another.

3.There are 112 different elements.

4.Water is not an element because it is made of more than one kind of atom. A water molecule is formed when two hydrogen atoms combine with an oxygen atom.

Answers for Page 57

1.Animal and plant cells include the following cell parts:

  • cytoplasm
  • cell membrane
  • nucleus
  • vacuole
  • mitochondria

2.Water and carbon dioxide are the byproducts of cellular respiration.

3.Chlorophyll allows a plant to make its own food.

4.Police could prove that a strand of hair found at the scene of a crime belongs to the suspect by comparing the DNA in the hair from the crime scene, to the DNA in the hair of the suspect.

Chapter 4 Review

Answers to Vocabulary Review (page 60)

1.True. Oxygen is an element because it is made of only one kind of atom.

2.False. Food molecules pass into a cell through the cell membrane.

3.False. A cell wall covers the cell membrane in plants.

4.True. Cell parts that help the cell store and use energy are called mitochondria.

5.False. Plants are green because they have chlorophyll.

6.True. The nucleus controls all the other parts of a cell.

7.False. Vacuoles float in the cytoplasm of a cell.

8.True. Chlorophyll is found in a chloroplast.

Answers to Chapter Quiz (page 61)

  1. Robert Hooke discovered cells.

2.The Periodic Table of Elements is a list of all elements.

3.Molecules are formed when atoms are joined by chemical bonds.

4.The nucleus is called the cell’s “command post” because it controls all the other parts of the cell.

5.Vacuoles store three things: food, water, and waste.

6.Answers will vary. Reasons why cells need energy may include three of the following:

  • to get and use food
  • to move
  • to grow
  • to reproduce
  • to respond

7.Food and oxygen are the two things that must pass into a cell in order for the cell to get energy.

8.Plant cells are able to make their own food because they have chlorophyll. Animal cells do not have chlorophyll.

9.The structure of a DNA molecule looks like a twisted ladder.

10.DNA determines a person’s eye color because the DNA contains a code that controls eye color.

Enrichment Activity: Discovering Cells

Background

All cells have many of the same structures. Plant cells are different from animal cells in a few important ways, however.

Purpose

You will describe a plant cell and then an animal cell.

What To Do

1.Imagine that you are very, very small. Write a paragraph about what it would be like to take a trip through a plant cell. Describe what you observe as you move around the part of the cell. Make sure you accurately describe cell structures, and that you include structures unique to plant cells.

2.Now imagine that you are taking a trip through an animal cell. Write a paragraph about your journey. Make sure that you accurately describe cell structures.

3.As you complete your journeys, make sure you consider the following questions:

  • What cell parts are you finding in both the plant cell and the animal cell?
  • What cell parts are in the plant cell but not in the animal cell?

Draw Conclusions

Based on your imaginary journeys, what can you conclude about plant cells and animal cells?

Answer: The cell membrane, cytoplasm, nucleus, vacuoles, and mitochondria are cell parts found in both plant cells and animal cells. The cell wall and chloroplasts are found in plant cells but not in animal cells. You would conclude that plant cells and animal cells share some characteristics but are different in some important ways.

If you found this material difficult, review the chapter. Otherwise, proceed with the assignment that follows.

Assignment 4

For information on completing assignments, refer to the instructions entitled “Getting Started.” Then begin this assignment by giving your full name, address, and phone number. Also list the name of this course, Assignment 4, your instructor’s name, and the date. Be sure to include the question number along with each answer. This assignment is worth 100 points.

Vocabulary

Give the correct term for the following definitions.
(2 points each)

1.the smallest, most basic unit of life

2.matter that is made of only one kind of atom

3.two or more atoms that are joined by chemical bonds

4.the watery substance in a cell

5.the thin covering that holds the cell together

6.the part of a cell that controls all the other parts

7.a part of the cell that stores food, water molecules, and waste

8.the process cells use to release energy from food molecules

9.a green material in plants that allows plants to make their own food

10.a molecule that controls the characteristics of living things

Multiple Choice

Answer the following questions by choosing the correct answer. (3 points each)

11.Which of the following statements is true about microscopes?

a.They make things look much smaller than they really are.

b.They are used for observing distant stars.

c.They make things look much bigger than they really are.

12.How did Robert Hooke discover cells?

a.by looking at tree bark under a microscope

b.by splitting the atom

c.by combining oxygen and hydrogen

13.What is a chemical bond?

a.a force that holds atoms together

b.part of a microscope

c.the thin covering that holds a cell together

14.Which of the following statements is true?

a.Cells are found only in plants.

b.Every living thing has at least two cells.

c.Cells are the building blocks of life.

15.Where in the cell are food molecules broken down?

a.the mitochondria

b.the nucleus

c.the vacuole

16.Which part of the plant cell stores chlorophyll?

a.a mitochondrion

b.a cell wall

c.a chloroplast

17.Why can a tree make its own food?

a.Each leaf cell contains cytoplasm.

b.Each leaf cell has a nucleus.

c.Each leaf cell has chloroplasts.

18.Which of the following statements is true?

a.Plant and animal cells are identical.

b.A plant cell has some structures that an animal cell does not have.

c.An animal cell has some structures that a plant cell does not have.

19.Which of the following statements is true about DNA?

a.It controls many of the characteristics of living things.

b.It is one of the shortest molecules found in living things.

c.Organisms in the same species all have identical DNA.

20.Which of the following statements about cancer cells is true?

a.They appear identical to healthy cells when looked at with a microscope.

b.They reproduce quickly and can crowd out and kill a person’s healthy cells.

c.Doctors offer no treatment because eventually the cells will stop reproducing.

Short Answer

Respond to the following questions with brief, complete answers.

21.Imagine an animal cell as a city. Consider the parts of a city: the land on which it is built, the city’s border, and government offices or a city hall. Other components are the various stores, gas stations, and places of business, and the people who live and work in the city. Compare five parts of the animal cell to five similar city parts. (20 points)

22.You are a reporter following a criminal case where DNA may play a key role in helping to convict a suspect. As your newspaper article needs to include a brief explanation of what DNA is, prepare a draft of your text by answering the following questions:

a.What is DNA and where is it found? (9 points)

b.How does DNA control the characteristics of living things? (9 points)

c.Give three examples of DNA-controlled human characteristics that might help support witness testimonies. (12 points)