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Biology 103 Unit 1 Cheat Sheet by

Biology 103 Unit 1 Cheat Sheet

General Terms

A body of knowledge about the natural world and an eviden­ce-­based process for generating that knowledge. Biology is the scientific study of the living world.
Hypotheses can be tested with observ­ational studies, experi­ments, or both.
Scientific Theory
A major explan­ation about the natural world that has been repeatedly confirmed in diverse ways and is accepted as part of scientific knowledge.
Scientific Fact
A direct and repeatable observ­ation of a particular aspect of the natural world.
Scientific Method
Involves making conjec­tures (hypot­heses), deriving predic­tions from them as logical conseq­uences, and then carrying out experi­ments or empirical observ­ations based on those predic­tions.
Two or more aspects of the natural world behave in an interr­elated manner.
The capacity of one variable to influence another.

The Biological Hierarchy

Tissue­(Ne­rvous Tissue)
Organ system­(Ne­rvous system)
Population (All organisms of the same species in a particular enviro­nment)
Community (Envir­onment and all living organisms)
Biosphere (Earth)


Algae, amoebas, and their relatives.
All plants.
From yeasts to mushrooms.
All animals with backbo­nes­(ve­rte­brates) and those withou­t(i­nve­rte­bra­tes).


Lacks an organized nucleus and other membra­ne-­bound organe­lles. Prokar­yotic DNA is found in a central part of the cell called the nucleoid. The cell wall of a prokaryote acts as an extra layer of protec­tion, helps maintain cell shape, and prevents dehydr­ation.
Larger than Prokaryote cells, has membra­ne-­bound organelles a true nucleus and rod shaped chromo­somes. The nucleus houses the cell's DNA and directs the synthesis of proteins and ribosomes.

Prokar­yotes Asexual Reprod­uction

Binary fission
Asexual reprod­uction by a separation of the body into two new bodies. In the process of binary fission, an organism duplicates its DNA and then divides into two parts (cytok­ine­sis), with each new organism receiving one copy of DNA.
Lateral gene transfer (horiz­ontal)
The acquis­ition of genetic material from another organism without being its offspring
Bacterial conjug­ation
A process in which bacterium actively trade DNA with another bacterium.
When a bacterium dies, the cell may burst open and release DNA and may be taken up by another bacterium, or even different species. The bacterium that take on the DNA are transf­ormed. Genes for bacterial resistance may move from one species to another in this way.

Bacterial Conjun­ction


A virus is a micros­copic, noncel­lular infectious particle. Most viruses are little more than genetic material wrapped in proteins, yet they can attack and devastate organisms in every kingdom of life—b­act­eria, archaeans, protists, fungi, plants, and animals.
Like living organisms, viruses can have DNA, they can reproduce, and they evolve.
A virus is much smaller and simpler than a cell and usually consists of genetic material (DNA or RNA) wrapped in a coat of proteins.
Viruses lack organelles needed for critical cellular functions so they make the cells of other organisms do the work for them.

Scientific Method

Charac­ter­istics of Life

Composed of one or more cells.
Reproduce using DNA.
Obtain energy from their enviro­nment to support metabo­lism.
Sense their enviro­nment and respond to it.
Maintain a constant internal enviro­nment (homeo­sta­sis).
Can evolve as groups.

Three Domains of Life

Bacteria and Archaea: Composed of single­-celled organisms. Bacteria and Archaea are substa­ntially different because they diverged from each other billions of years ago and have been evolving separately ever since. Because they are superf­icially similar, they have been lumped together as Prokar­yotes.

Eukarya: Includes single­-celled and multic­ellular forms.

Energy Flow

Anatomy of Typical Bacteria

Energy Use

They obtain energy from the nonliving part of their enviro­nment, such as sunlight or inorganic chemical compounds.
They obtain energy from the living or once-l­iving part of their enviro­nment, such as by consuming other organisms or organic matter.
They absorb the energy of sunlight and take in carbon dioxide to conduct photos­ynt­hesis.
Organisms that make food from carbon dioxide and energy extracted from chemicals in their enviro­nment.
Chemoa­uto­throphs that tap energy from minerals.
Organisms that obtain energy and carbon from organic molecules. These are simply organisms that consume other organisms. All animals and fungi, and many protists, are chemoh­ete­rot­rophs.
Use light as an energy source (as do plants) but get their carbon from organic material (not from carbon dioxide as plants do).

Virus Structure



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