BIO 143 Study Guide - Midterm Guide: Heat Capacity, Hydrophile, Cell Membrane

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8 Jun 2018
BIO143 EXAM 1 Study Guide
Chapter 1: An Introduction to Life on Earth
I. How do scientists study life?
A. Life can be studied at different levels
1. Living things are composed of atoms
a. Atoms—smallest particle of elements
B. The scientific method is the basis for scientific inquiry
1. The scientific method includes a number of steps (Figure 1.4)
a. Observation—observe a phenomenon
b. Question—form a question about the phenomenon
c. Hypothesis—supposition based on previous observations
that is offered as an explanation
d. Prediction—an “If…then” statement based on the
e. Experiment—designed to test hypotheses
f. Conclusion—can be drawn on the basis of results of
2. Variables are factors that may affect the outcome of an
3. Controls are “controlled” variables so that they remain constant
C. Scientific theories have been thoroughly tested
1. Scientific theory is an explanation of natural phenomena
developed through extensive and reproducible observations
2. Science is based on reasoning
a. Inductive reasoning—process of creating a generalization
as a result of making many observations that support it and
none that contradict it
b. Deductive reasoning—generating a hypothesis based on
well-accepted scientific theory
3. Scientific theories are formulated in ways that can be potentially
II. Evolution: The unifying theory of biology
A. Three natural processes underlie evolution
1. Genetic variability—differences in DNA
2. Inheritance of genetic variations (mutations)
3. Natural selection—preservation of genes that help an organism
survive and reproduce
III. What are the characteristics of living things?
A. Living things are composed of cells
1. Cell theory states that the cell is the basic unit of life
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BIO143 EXAM 1 Study Guide
2. Cells contain
a. Genes—units of heredity
b. Organelles—inside cells
c. Plasma membrane—encloses cytoplasm
B. Living things maintain homeostasis
1. Homeostasis maintains constant internal conditions
2. Example is maintenance of body temperature
C. Living things respond to stimuli
D. Living things acquire and use materials and energy
1. Nutrients are materials organisms need for survival
2. Energy is the ability to do work
3. Autotrophs conduct photosynthesis to produce food for
4. Heterotrophs acquire energy by eating other organisms (some
parasites such as helicobacter pylori—bacteria that causes
ulcers—feed off of a host organism)
E. Living things grow
F. Living things reproduce themselves
1. Continuity of life involves giving rise to offspring of the same type
G. Living things, collectively, have the capacity to evolve (adapt to
IV. How do scientists categorize the diversity of life?
A. The domains bacteria and archaea consist of prokaryotic cells; the domain
eukarya is composed of eukaryotic cells
1. Prokaryotic cells do not contain a nucleus; genetic material is in
2. Eukaryotic cells contain a nucleus that houses genetic material;
contain organelles
B. Bacteria and archaea are mostly unicellular; members of kingdoms fungi,
plantae, and animalia are nearly all multicellular
C. Members of the different kingdoms have different ways of acquiring
1. Autotrophs are organisms that are able to produce their own
2. Heterotrophs are organisms that acquire energy
Also, study vocabulary words listed at the end of the chapters that we have discussed in
lecture. If we haven’t mentioned the word in lecture, do not worry about its definition. It
is also recommended that you study/answer the review questions at the end of the
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BIO143 EXAM 1 Study Guide
Chapter 2: Atoms, molecules, and life
I. What are atoms?
A. Atoms, the basic structural units of elements, are composed of still smaller
1. Atoms are the basic structural units of matter
a. Atomic nucleus—positively charged protons and
b. Orbit atomic nucleus—negatively charged electrons
2. Elements are atoms with the same number of protons (atomic
a. Atomic mass is equal to the mass of the protons,
neutrons, and electrons (the mass of electrons is so small
that it changes the mass very slightly; so for simplicity
calculate the atomic mass by add the number of protons
and electrons)
b. Isotopes—same element; different number of neutrons,
but same number of protons and electrons
c. Radioactive isotopes release energy; when isotopes
undergo decay (breakdown) the unstable neutron changes
into a proton and releases a low energy electron which is
the cause of radioactivity
3. Electrons travel within specific regions called electron shells that
correspond to different energy levels
a. Electron shells allow interactions, or bonds, with other
4. Life depends on the ability of electrons to capture and release
II. How do atoms interact to form molecules?
A. Atoms interact with other atoms when there are vacancies in their
outermost electron shells
1. A molecule consists of two or more atoms of the same or
different elements held together by interactions between their
outer shell electrons
B. Free radicals are highly reactive and can damage cells
1. Free radicals are unstable molecules with an unfilled outermost
electron shell
a. Steal electrons to complete outermost electron shells
b. Antioxidants donate electrons to free radicals to stabilize
C. Chemical bonds hold atoms together in molecules
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