Layman D. Biology Demystified: A Self-Teaching Guide

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The separated 46 chromosomes are thus moved into opposite poles or ends of

the cell. Finally, a cleavage furrow appears as a narrow groove between the

two pinching-oﬀ poles of the parent cell. The cleavage furrow is eventually

replaced on either side by a complete new cell membrane. The ultimate result

– two separate daughter cells, each with an identical set of 46 single chromo-

somes of their own. Eventually, each of these daughter cells enters into its

own Cell Cycle, beginning with another interphase. By this means, body

growth and replacement of worn or damaged cells readily occurs within

our human body tissues.

Cancer: A Severe Disorder of Mitosis

In a normal mitosis, the orderly duplication and division of chromosomes,

along with the division of the cytoplasm, creates two identical daughter cells.

Both of these daughter cells are normal, as well. Thus, they go about doing

whatever body task they have been genetically programmed to perform.

Epithelial cells, for example, frequently divide and replace themselves with

daughters, each daughter cell in turn performing a body covering or cavity-

lining function.

But what can happen if an abnormal ‘‘change’’ (mut)ormutation (mew-

TAY-shun) in the genetic program occurs? One of the really bad results can

be cancer! The English meaning (and the astrological sign) for cancer, of

course, is the ‘‘crab’’! An alternate translation for cancer is ‘‘creeping ulcer.’’

Cancer is like a stubborn crab that can aﬄict either epithelial tissues (like

the skin) or connective tissues (such as bone). When a person has a cancer, it

is like a crab with pinchers, because it seems to hold on and not let go,

making it very diﬃcult to treat! Even worse, cancer has the characteristics

of a creeping ulcer, because it often spreads from one aﬀected site of the

body, to many other sites. Small wonder, then, that various forms of cancer

are a leading cause of death in many countries around the world.

The exact cause of cancer in human beings, unfortunately, is still

unknown. But various chemical agents, called carcinogens (car-SIN-oh-

jens), are suspected cancer or ‘‘crab’’ (carcin) ‘‘producers’’ (-gens).

Prominent among these suspected carcinogens are the poisonous or toxic

chemicals present in cigarette smoke, which are thought to be the leading

cause of lung cancer. The carcinogens may trigger abnormal changes (muta-

tions) in the DNA of epithelial or connective tissue cells. The mutations

create errors in the genetic program of the Cell Cycle, such that the resulting

daughter cells are highly abnormal. The mutated, cancerous daughter cells

CHAPTER 5 Cells: The ‘‘Little Chambers’’ 87

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5, Order

2, Disorder

3, Disorder

have a largely unregulated, disorganized, and extremely rapid rate of mitosis.

When these cancerous cells form larger tumors, the tumors interfere with the

function and nutrition of normal cells. Eventually, the normal tissue cells die

or are crowded out. If this process goes on long enough, the cell metabolism

of the aﬀected person may be so abnormally changed that the person dies.

Quiz

Refer to the text in this chapter if necessary. A good score is at least 8 correct

answers out of these 10 questions. The answers are found in the back of this

book.

1. The word, cell, comes from the Latin for:

(a) ‘‘Crabs’’

(b) ‘‘Mice’’

(d) ‘‘A chamber’’

2. The Modern Cell Theory:

(a) Explains that the cell is the basic unit of all living things

(b) Holds that, while cells are important, one must seek better

explanations of anatomy and physiology at a diﬀerent level of

biological organization

microscope

(d) Supports the concept that cell abnormality has no relationship to

disease

3. An organelle always lacking from a prokaryote cell (such as a

bacterium):

(a) Ribosome

(b) ER

(d) Nucleus

4. Organelles that store digestive enzymes:

(a) Lysosomes

(b) Mitochondria

(d) Microtubules

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PART 2 Universal Building Blocks of Life

5. ER:

(a) Stands for ‘‘Emergency Reserves’’ within cells

(b) Is a complex network of ﬂattened sacs that circulates materials

throughout the cell

(d) Has no known function within most cells

6. Codons:

(a) Consist of particular chains of amino acids within proteins

(b) Are not found within chromatin

(d) Essentially play the same roles as peptide bonds

7. During transcription:

(a) Messenger RNA makes a copy of exposed DNA bases

(b) Transfer RNA matches up with mRNA

together

(d) A protein is manufactured from raw cellular materials

8. The cell membrane is described as selectively permeable, because:

(a) All types of particles are able to freely enter and leave the cell

(b) Certain particles are allowed to pass through it, while others are

blocked

(d) No objects are allowed to permeate it

9. The overall movement of oxygen molecules from a high O

concentration in the extracellular ﬂuid, to a lower O

concentration in

the intracellular ﬂuid is called:

(a) Simple diﬀusion

(b) Osmosis

(d) Electrolyte imbalance

10. The longest portion of the Cell Cycle, during which protein synthesis

and duplication of chromosomes occurs is known as:

(a) Daughter cell cleavaging

(b) Interphase

(d) Normal cell stimulation by carcinogens

CHAPTER 5 Cells: The ‘‘Little Chambers’’ 89

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The Giraﬀe ORDER TABLE for Chapter 5

(Key Text Facts About Biological Order Within An Organism)

1. ____________________________________________________________

2. ____________________________________________________________

3. ____________________________________________________________

4. ____________________________________________________________

5. ____________________________________________________________

The Dead Giraﬀe DISORDER TABLE for Chapter 5

(Key Text Facts About Biological Disorder Within An Organism)

1. ____________________________________________________________

2. ____________________________________________________________

3. ____________________________________________________________

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PART 2 Universal Building Blocks of Life

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Test: Part 2

DO NOT REFER TO THE TEXT WHEN TAKING THIS TEST. A good

score is at least 18 (out of 25 questions) correct. Answers are in the back of

the book. It’s best to have a friend check your score the ﬁrst time, so you

won’t memorize the answers if you want to take the test again.

1. The water (H

O) molecule:

(a) Is an example of a crystal

(b) Unequally shares outermost electrons between its O and H atoms

(d) Equally shares outermost electrons between its O and H atoms

(e) Is one of the least common types of molecules within most

organisms

2. Both H

O and NaCl diﬀer from CO

in that they:

(a) Are important organic compounds

(b) Do not contain chemical bonds

(d) Never react with other particles

(e) Are both mainly ionic in their bonding

3. The main reason you shouldn’t swim in salty water during a

thunderstorm is:

(a) Lightning might strike and topple a nearby tree, hitting you on the

head!

(b) Sodium chloride is very salty and irritating to the eyes and skin

contains only inorganic ones

(d) Lightning might strike the water, and its electrons be carried to

your body by ions

(e) The rain might wash organic solvents into the surrounding

seawater

4. C–C bonds:

(a) Can create long chains, branching trees, or closed-ring molecules

(b) Always bond with hydrogen and oxygen at the same time

molecules

(d) Create a highly orderly inorganic skeleton for many body

molecules

(e) Seldom occur within the membranes of living cells

5. General name for the fats and fat-like hydrocarbons that cannot

dissolve in water:

(a) Enzymes

(b) Lipids

(d) Krebs cycle electron carriers

(e) Nucleic acids

6. Type of energy released by action of ATPase:

(a) Potential energy

(b) Motivational juice

(d) Consumption of calories

(e) Cold stimulus

7. Adenosine diphosphate:

(a) Represents a reduced, lower-energy form of ATP

(b) Continuously degrades into free energy, electrons, and O

(d) Is regenerated whenever the cell has an excess of energy

(e) May be important in humans and animals, but not in plants

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PART 2 Universal Building Blocks of Life

8. You chew up and swallow a hamburger. Within your stomach and

small intestine, it is further digested into individual proteins and amino

acids, which in turn are ﬁnally broken down to provide free energy. The

overall name for this process is:

(a) Cannibalism

(b) Anabolism

(d) Metabolism

(e) Catabolism

9. After a portion of a tree trunk is gouged by a saw, the trunk slowly

repairs itself, then continues growing. The general terms for these

physiological operations are:

(a) Mitosis & anabolic processes

(b) Mitochondrial enzymatic action

(d) Stepwise decreases in Biological Order and pattern

(e) Random osmosis/diﬀusion

10. Plant cells consume carbon dioxide as part of their metabolism because:

(a) Cellular respiration always involves the net consumption of CO

(b) The Calvin cycle starts with a group of C atoms coming from CO

(d) CO

molecules, not O

molecules, have enough energy in their

bonds to make ATP

(e) Most plants live in low-oxygen environments

11. All the greenish parts of a plant contain _____ with chlorophyll

molecules:

(a) Rough ER

(b) Cell nuclei

(d) Lysosomes

(e) Chloroplasts

12. Cellular respiration:

(a) Occurs right after glycolysis under anaerobic conditions

(b) Utilizes O

to catabolize carbohydrates, lipids, or proteins

(d) Involves the production of lactic acid, under aerobic conditions

(e) Takes place within the cytoplasm

13. The Krebs cycle:

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PART 2 Test 93

(a) Produces hydrogen-carrier molecules, which then move onto the

cristae of the mitochondria

(b) Is named for the concert pianist Krebs Kuhdiddlehopper

(d) Is much less eﬃcient than glycolysis in producing ATP molecules

(e) Has carbon as its ﬁnal electron acceptor

14. Schleiden & Schwann are especially noted for:

(a) Advancing the Modern Cell Theory

(b) Being the ﬁrst to use the word, ‘‘cell’’

(d) Painting pictures of organisms upon cave walls

(e) Successfully disproving the conclusions of Robert Hooke

15. The word lysosome translates into Common English to mean:

(a) ‘‘Breakdown body’’

(b) ‘‘Kernel-resembler’’

(d) ‘‘Tiny digester’’

(e) ‘‘5-carbon sugar body’’

16. A packager of proteins, lipids, hormones, and various cell products:

(a) Lysosome

(b) Golgi body

(d) Rigid cell wall

(e) Nuclear membrane

17. A cytoskeleton:

(a) Often cracks into tiny particles

(b) Provides pores in the nuclear membrane

(d) Consists of microtubules as well as microﬁlaments

(e) Makes each cell extremely weak and fragile

18. A single gene is important because:

(a) It provides a code or blueprint for the production of a certain

protein

(b) Most cells contain no more than one gene

(d) Each gene provides a speciﬁc code for some type of membrane

transport

(e) No DNA is present without it

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PART 2 Universal Building Blocks of Life

19. If all the tRNAs within a cell were suddenly destroyed, _____ would be

directly and immediately aﬀected:

(a) Osmosis

(b) Transcription

(d) Intracellular transport

(e) Translation

20. A polypeptide gets its name from the fact that:

(a) It consists of a series of unattached amino acids

(b) The word mitosis also has the same meaning

(d) The molecule contains peptide bonds between its amino acid

subunits

(e) There is nothing else quite like it within the living plant/animal

body

21. One of the main reasons that body tissues do not become clogged with

millions of dead cells:

(a) Quick occurrence of autolysis

(b) Microscopic ‘‘vacuum-cleaners’’ within the cytoplasm

(d) Just enough mitochondria to provide the needed energy

(e) A massive allergic reaction to the dead cells

22. Active transport systems diﬀer from passive transport systems by their:

(a) Lack of importance in protein synthesis

(b) Use of free energy from the splitting of ATP

(d) Stickiness and rubbery texture

(e) Participation in cellular movements

23. Like simple diﬀusion, osmosis:

(a) Proceeds from an area of higher to one of lower concentration

(b) Occurs from an area of lower to one of higher concentration

O molecules only

(d) Directly releases energy to support cell metabolism

(e) Interferes with normal cellular digestion

24. Facilitated diﬀusion shares a certain major feature with active

transport:

(a) Energy-free scattering of particles

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PART 2 Test 95

(b) ‘‘Thrusting’’ of particles from a region where their concentration is

low, up to a region where their concentration is high

(d) Dependence upon the action of protein carrier molecules

(e) Breaking down of glucose

25. Mitosis is:

(a) The orderly division of paired, duplicated chromosomes into

single, unpaired chromosomes

(b) A complete destruction of 46 chromosomes

(d) Removal of mitochondria from the cytoplasm

(e) The same thing as interphase

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PART 2 Universal Building Blocks of Life