view of the cell ch01_lecture

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Copyright 2005 Brooks/Cole Thomson Learning

Biology Solomon Berg Martin

Chapter 1

A View of Life


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Biology CHAPTER 1 A View of Life

The Human Genome Project mappedthe complete set of human genes Genomics analyses the DNA

sequence of an organism While genomics will lead to

breakthroughs in science, it also

raises ethical concerns Safeguarding the privacy of geneticinformation, for example


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Living organisms composed of cells Unicellular organisms

Single cell

Multicellular organisms Many cells organized to form

tissues, organs, and organ systems


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Cells Plasma membrane regulates

passage of materials

Specialized molecules (usuallyDNA) contain genetic instructions

Internal structures called

organelles perform specificfunctions


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Types of cells Prokaryotic cells, exclusive to

bacteria and microscopic

organisms Eukaryotic cells contain a variety

of organelles, including a

nucleus, which houses DNA


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Biological growth Increase in the size of cells, the

number of cells, or both

Development Includes all the changes that take

place during an organisms life

Structures and body form areadapted to an organismsfunctions


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Metabolism processes Chemical reactions and energy

transformations

Essential to nutrition, growth andrepair of cells, and conversion ofenergy

Regulation of metabolicprocesses maintainshomeostasis




Stimuli Physical or chemical changes in

the internal or external

environment The organism responds to, for

example, changes in

Light Temperature, pressure, or sound The chemical composition of soil




Locomotion Simpler organisms

Amoeboid movement

The beating of cilia or flagella Animals

Move by contracting muscles Some are sessile and have cilia or

flagella Plants respond to light, water, etc.




Asexual reproduction and sexual reproduction




Adaptation Populations evolve to better

survive

Adaptations Characteristics that enhance an

organisms ability to survive in a

particular environment May be structural, physiological,behavioral, or a combination




The hierarchyof biologicalorganizations




The cell Consists of atoms and molecules Is the basic unit of life In multicellular organisms,

associates to form tissues




Tissues In animals, an example is muscle In plants, an example is epidermis

Tissues are organized intoorgans

Tissues and organs form organsystems


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To carry on life processes, anorganism must have Precise instructions

Communication among cells This information is coded and

delivered by Chemical substances Electric impulses




DNA is the large molecule thatmakes up genes Genes specify instructions for

making every living organism Watson and Crick worked out

structure of DNA in 1953




DNA consists of twochains of atomstwisted into a helix




DNA contains recipe forproteins Proteins determine structure and

function of cells and tissues




In multi-cellular organisms,communication with and amongcells is critical

Some proteins are important inthis communication

Cell-to-cell communication is acomplex process called cellsignaling




Information transmitted from onepart of the body to another isimportant in regulating life

processes Information is transmitted by

Hormones Neurotransmitters and their

receptors

f f




Evolution is the unifying conceptof biology Biology

Hierarchical classification scheme Identifies the approximately 1.7

million species of living organisms

Bi l CHAPTER 1 A Vi f Lif




Systematics studies the diversityof organisms and theirevolutionary relationships

Taxonomy is the science ofnaming and classifying organisms

Bi l CHAPTER 1 A Vi f Lif




Binomial system ofnomenclature Developed in the 18th century by

Linnaeus, a Swedish botanist Names and classifies organisms Basic unit is a species Each species assigned a two-part

name

Bi l g CHAPTER 1 A View of Life


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Binomial system ofnomenclature uses a series oftaxonomic categories from

species to domain



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Each category ismore general andmore inclusivethan the onebelow it



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Natural selection Theory of evolution developed by

Darwin and Wallace

The Origin of Species by NaturalSelection published in 1859



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Natural selection based on fourobservations Members of a species show

variation Organisms produce many more

offspring than will survive

Organisms compete Only some survive to reproduce



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Biology V

Egg masses ofthe wood frog Many moreproduced than

can survive



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Biology

Variation among individuals Result of different varieties of

genes that code each

characteristic Ultimate source of variation is

random mutation

Chemical or physical changes inDNA that can be inherited Modifies genes



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o ogy

Every cell of an organismrequires nutrients Certain nutrients are used as

fuel for cellular respiration Virtually all cells carry on cellular

respiration



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gy

A self-sufficient ecosystemcontains three types oforganisms

Producers Consumers Decomposers



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gy

Ecosystems depend oncontinuous input of energy Organisms can neither create

energy nor use it with completeefficiency

During every energy transaction,some is lost to the environmentas heat



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gy

Energyflow



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The scientific method involvessystematic thought Deductive reasoning draws

conclusions from premises Inductive reasoning begins with

observations and draws

conclusions or extrapolates



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The scientificmethod involvesordered steps Hypothesis Method Results Conclusion

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