Chapters 1 & 2 Flashcards
What is the core theme of biology?
Evolution
The process of change that has transformed life on Earth
7 Characteristics of Life
- Order (organization)
- Evolutionary adaptation
- Response to environment
- Reproduction
- Growth and development
- Energy processing
- Regulation
10 Levels of Biological Hierarchy (Biggest level to smallest level)
- Biosphere
- Ecosystem
- Community
- Population
- Organism
- Organs and Organ System
- Tissue
- Cell
- Organelles
- Molecule
Biosphere
all environments (everything) on Earth
Ecosystem
all living and nonliving things in a particular area
Community
all organisms (living things) in an ecosystem
Population
all individuals of a species in a particular area
Organism
an individual living thing (one single organism)
Organs and Organ Systems
specialized body parts made up of tissues. Ex: heart, stomach
Tissue
a group of similar cells
Cell
life’s fundamental unit of structure and function. (cells are alive)
Organelles
a structural component of a cell (building blocks of a cell)
Molecule
a chemical structure consisting of atoms
Emergent Properties
new properties that arise with each step upward in the hierarchy of life owing to the arrangement and interactions of parts as complexity increases.
Emergent properties characterize nonbiological entities as well.
Ex: Bike
Emergent Properties- put them/things together
Reductionism
is the reduction of complex systems to simpler components that are more manageable to study.
Ex: the molecular structure of DNA v. heredity
An understanding of biology balances reductionism with the study of emergent properties.
Reductionism- breaks things apart
Life requires energy transfer and transformation
Living organisms transform energy from one form to another
food (chemical energy)»_space; motion (kinetic energy)
Two Rules of Ecosystem Dynamics (how they work)
The two major processes that the dynamics of an ecosystem include
- Chemical nutrients recycle (chemicals cycle)
2. Energy flows- usually enters as sunlight exits as heat
Structure and Function of living organisms
are closely related.
By looking at the structure we can figure out the function.
The fundamental unit of life
Cell
The lowest level of organization that can perform all activities required for life (Order, evolutionary adaptation, response to the environment, reproduction, growth and development, energy processing, regulation)
The Cell
All Cells
- are enclosed by a membrane (outside part)
- use DNA as their genetic material (inside part)
Two main forms of cells are
Eukaryotic Cell and Prokaryotic Cell
Eukaryotic Cell
has membrane-enclosed organelles, the largest of which is usually the nucleus
(have internal membrane)
Prokaryotic Cell
is simpler and usually smaller, and does not contain a nucleus or other membrane-enclosed organelles
(doesn’t have internal membrane. normally much smaller)
(bacteria)
the ability of cells to divide is
the basis of all reproduction, growth, and repair of multicellular organisms
DNA is
a simple molecule.
Each DNA molecule is made up of two long chains arranged in a double helix
A, G, C, and T
each link of a chain is one of four kinds of chemical building blocks called nucleotides and nicknamed A, G, C, and T.
Its all about the order of things and order of the nucleotides
A gene codes for
protein
DNA»_space; RNA» Protein
DNA is transcribed into RNA then translated into a protein
Negative Feedback
means that as more of a product accumulates, the process that creates it slows and less of the product is produced.
ATP generation
Positive Feedback
means that as more of a product accumulates, the process that creates it speeds up and more of the product is produced
Blood clotting
Taxonomy
is the branch of biology that names and classifies species into groups of increasing breadth
Domains followed by kingdoms are the broadest units of classification
Organisms are divided into three domains
the three domains of life
Domain Bacteria (prokaryotic-unicellular) Domain Archaea (prokaryotic-unicellular) Domain Eukarya (eukaryotic)
Domain Bacteria
Prokaryotic-unicellular.
has no nucleus.
it is anything normal that lives on skin or in lungs or in normal areas or normal environments
Domain Archaea
Prokaryotic-unicellular.
has no nucleus.
it is anything weird that lives in like volcanoes or really cold environments or just weird environments
Domain Eukarya
Eukaryotic.
anything that has a nucleus.
It has four kingdoms that can be distinguished by how they get their food:
- Kingdom Plantae
- Kingdom Fungi
- Kingdom Animalia
- Protists.
Kingdom Plantae
photosynthetic
multicellular
Kingdom Fungi
absorb nutrients
multicellular
Kingdom Animalia
ingest their food
multicellular
Protists
unicellular
many kingdoms
DNA is the
universal genetic language common to all organisms.
Unity is evident in many features of cell structure
natural selection
results in the adaptation of organisms to their environment
Evolution occurs at
the population level
Inquiry
is the search for information and explanation
The scientific process includes
making observations, forming logical hypotheses, and testing them
Types of Data
Qualitative
Quantitative
Qualitative
descriptions rather than measurements.
Descriptive
Quantitative
recorded measurements, which are sometimes organized into tables and graphs (NUMBERS).
Numerical
Hypothesis
is a tentative answer to a well framed question (if … then)
They are NOT best guesses.
They are usually narrow in scope.
A scientific hypothesis leads to predictions that can be tested by observation or experimentation
Failure to falsify a hypothesis
does not prove that hypothesis.
Nothing “proves” a hypothesis beyond a shadow of a doubt
Inductive Reasoning
draws conclusions through the logical process of induction.
Repeat specific observations can lead to important generalizations.
Specific –> General
Observations and inductive reasoning can lead us to ask questions and propose hypothetical explanations called hypothesis
Deductive Reasoning
uses general premises to make specific predictions.
General –> Specific
Deductive Reasoning– If . . . Then . . .
A hypothesis must be
testable and falsifiable.
Supernatural and religious explanations are outside the bounds of science.
A theory is
- broader in scope than a hypothesis.
- general, and can lead to a new testable hypotheses.
- supported by a large body of evidence in comparison to a hypothesis
A controlled experiment
compares an experimental group with a control group.
A controlled experiment means that control groups are used to cancel the effects of unwanted variables.
Dependent Variables
what is the outcome. what depends on the entire experiment before something happens. the end.
Goes on the Y axis
Independent Variables
what “I” ,the researcher, does. the thing that is manipulated. what changes. the beginning.
Goes on the X axis.
Science VS. Technology
the goal of science is to understand natural phenomena.
The goal of technology is to apply scientific knowledge for some specific purpose.
Organisms are composed of
matter.
Matter
anything that takes up space and has mass.
Matter is made up of elements.
Carbon, Hydrogen, Oxygen, and Nitrogen
make up about 96% of living matter.
CHON
Most of the remaining 4% of living matter consists of
calcium, phosphorus, potassium, and sulfur
Trace elements
are those required by an organism in minute quantities.
Iodine, goiter.
minute- teeny tiny
An Element
is a substance that cannot be broken down to other substances by chemical reactions.
C, N, Na
A Compound
is a substance consisting of two or more elements in a fixed ratio
NaCl, H2O
A compound has characteristics different from those of its elements
An element consists of
unique atoms
An Atom
is the smallest unit of matter that still retains the properties of an element
Atoms are composed of
subatomic particles
Relevant subatomic particles inclue
- Neutrons (no electrical charge) (found in nucleus)
- Protons (positive charge)
- Electrons (negative charge)
Protons
+ charge.
determine element.
Neutrons
no charge.
determine isotope.
Electrons
- charge.
form negative cloud around the nucleus and determine chemical behavior
neutrons and protons form the
atomic nucleus.
Neutron mass and proton mass are almost identical and measured in
Daltons.
Proton= about 1 dalton (Weight)
Electrons do not
follow circular orbits around the nucleus.
instead they are constantly moving around the nucleus.
Atoms of various elements differ in
number of subatomic particles
An element’s atomic number is the
number of protons in its nucleus.
Atomic Number= # of protons
An element’s atomic mass is the
sum of protons plus neutrons in the nucleus.
Atomic Mass= P + N
Atomic mass
the atom’s total mass, can be approximated by the mass number
Atomic Mass= P + N + E
The mass number is
written as a superscript to the left of an element’s symbol
Mass Number= # of Protons + # of Neutrons
The atomic number is
written as a subscript to the left of an element’s symbol
Atomic Number= # of Protons
All atoms of an element have the same number of protons but may differ
in number of neutrons
Isotopes
are two atoms of an element that differ in number of neutrons
C12, C13, C14
Radioactive isotopes
decay spontaneously giving off particles and energy
Energy is
the capacity to cause change
Potential energy is
the energy that matter has because of its location or structure
The electrons of an atom differ in their amounts of
potential energy
An electron’s state of potential energy is called its
energy level or electron shell
First shell
can hold up to 2 electrons
Second shell
can hold up to 8 electrons
Third shell
can hold up to 8 electrons
The chemical behavior of an atom is determined by
the distribution of electrons in electron shells.
the valence electrons (in the outer shell)
Mostly always the number of protons will be the same as the
number of electrons, unless stated otherwise
Valence electrons
are electrons in the outermost shell, or valence shell
The Valence of an element
is how many electrons it still wants. the number of empty spots that need to be filled with electrons to fill the shell.
Elements with a full valence shell are chemically
inert
Valence tells you how many
bonds it’ll make and how many electrons are missing in the outer shell
Oxygen
6 valence electrons
valence of 2
Hydrogen
1 valence electron
Valence of 1
Carbon
4 valence electrons
valence of 4
Nitrogen
5 valence electrons
valence of 3
Covalent Bonds
strongest bonds you can make that happen by sharing the electrons.
A covalent bond is the sharing of a pair of valence electrons by two atoms.
Covalent bond= Strong. Share.
In a covalent bond, the shared electrons count as a part of each atom’s valence shell.
A Molecule consists of
two or more atoms held together by covalent bonds.
A single covalent bond, or single bond, is the
sharing of one pair of valence electrons
A double covalent bond, or double bond, is the
sharing of two pairs of valence electrons
Covalent bonds can form between
atoms of the same element or atoms of different elements
H20
a molecule and compound
H2
a molecule
Electronegativity
is an atom’s attraction for the electrons in a covalent bond
The more electronegative an atom,
the more strongly it pulls shared electrons toward itself
Two types of covalent bonds
Non-polar covalent bond and Polar Covalent Bond
Non-Polar Covalent Bonds
share electrons equally
Polar Covalent Bonds
share electrons UNequally.
One atom is more electronegative and the atoms do not share the electron equally.
Unequal sharing of electrons causes a
partial positive or negative charge for each atom or molecule
Ionic Bonds
weaker, and transfer electrons.
Atoms sometimes strip electrons from their bonding partners.
An example is the transfer of an electron from sodium to chlorine. NaCl
After the transfer of an electron, both atoms have charges.
A charged atom (or molecule) is called an
ion
NaCl
is an ionic bond.
A cation
is a positively charged ion
A anion
is a negatively charged ion
An ionic bond is an attraction between an
anion and a cation
Sodium loses an electron so it is a
cation
Na+
Chloride gains an electron so it is an
anion
Cl-
Most of the strongest bonds in organisms are
covalent bonds that form a cell’s molecules
Weak chemical bonds are
ionic bonds and hydrogen bonds
Weak chemical bonds reinforce
shapes of large molecules and help molecules adhere to each other
Hydrogen Bonds
weak, and form between molecules.
A hydrogen bond forms when a hydrogen atom covalently bonded to one electronegative atom is also attracted to another electronegative atom.
In living cells, the electronegative partners are usually oxygen or nitrogen atoms
Van Der Waals Interactions
Weak and asymmetrical electrons.
Van Der Waals Interactions are attractions between molecules that are close together as a result of these chargers.
(Asymmetrical electron distribution).
Collectively, such interactions can be strong, as between molecules of gecko’s toe hairs and a wall surface.
If electrons are distributed asymmetrically in molecules or atoms, they can result in “hot spots” of positive or negative charge.
All organisms on your campus make up
a community
which of the following is a correct sequence of levels in life’s hierarchy, proceeding downward from an individual matter?
Nervous system, brain, nervous tissue, nerve cell
Systems biology is mainly an attempt to
Understand the behavior of entire biological systems
Which of the following are observations or interferences on which Darwin’s theory of natural selection is based?
- There is heritable variation among individuals
- Because of overproduction of offspring, there is competition for limited resources
- Individuals whose inherited characteristics best fit them to the environment will generally produce more offspring
- A population can become adapted to its environment over time
Protists and bacteria are grouped into different domains because
Protists have a membrane-bounded nucleus, which bacteria cells lack
Which of the following best demonstrates the unity among all organisms?
The structure and function of DNA
A controlled experiment is one that
Tests experimental and control groups in parallel
Which of the following statements best distinguishes hypotheses from theories in science?
Hypotheses usually are relatively narrow in scope; theories have broad explanatory power
Which of the following is an example of qualitative data?
The fish swam in a zigzag motion
Which of the following best describes the logic of scientific inquiry?
If my hypothesis is correct, I can expect certain test results
in the term trace element, the adjective trace means that
the element is required in very small amounts
compared with 31P, the radioactive isotope 32P has
one more neutron
the reactivity of an atom arises from
the existence of unpaired electrons in the valence shell
which statement is true of all atoms that are anions?
The atom has more electrons than protons
Which of the following statements correctly describes any chemical reaction that has reached equilibrium?
The rates of the forward and reverse reactions are equal
We can represent atoms by listing the number of protons, neutrons, and electrons—for example, 2p+, 2n0, 2e- for helium. Which of the following represents 18O isotope of oxygen?
8p+, 10n0, 8e-
the atomic number of sulfur is 16. Sulfur combines with hydrogen by covalent bonding to form a compound, hydrogen sulfide. Based on the number of valence electrons in a sulfur atom, predict the molecular formula of the compound.
H2S
What coefficients must be placed in the following blanks so that all atoms are accounted for in the products?
C6H12O6 →______ C2H6O + ______ CO2
2; 2
A substance that cannot be broken down into other substances by ordinary chemical procedures is a(n) _____.
element
Which of the following is a trace element required by most living organisms?
magnesium
Which of the following subatomic particles always has a positive charge?
proton
Changing the number of _____ would change an atom into an atom of a different element.
protons in an atom
The atoms of different phosphorus isotopes _____.
have different numbers of neutrons
The type of bonding and the numbers of covalent bonds an atom can form with other atoms is determined by _____.
the number of unpaired electrons in the valence shell
A carbon atom and a hydrogen atom form what type of bond in a molecule?
nonpolar covalent bond
An ionic bond is formed when _____.
one atom transfers an electron to another atom
Hydrogen bonding is most often seen _____.
when hydrogen is covalently bonded to an electronegative atom
Chemical equilibrium is reached when _____.
The forward and reverse reactions occur at the same rate so that the concentrations of reactants and products remain the same
An organ, such as the liver, is composed of _____.
tissues
Which of these is an organ system?
digestive
What are the two main types of cells?
Prokaryotes and Eukaryotes
Which of the following is true?
Bacteria can mutate within the human body
The innermost electron shell of an atom can hold up to _____ electrons.
2
Which of these relationships is true of an uncharged atom?
The number of protons is equal to the number of electrons
What determines the types of chemical reactions that an atom participates in?
the number of electrons in the outermost electron shell
`An atom is least likely to participate in a reaction when
its outermost shell is stable.
What is the atomic number of an atom that has 6 protons, 6 neutrons, and 6 electrons?
6
Which of these refers to atoms with the same atomic number but different atomic masses?
these atoms are isotopes
Atoms with the same atomic number and different atomic masses are referred to as
isotopes.
Fluorine’s atomic number is 9 and its atomic mass is 19. How many neutrons does fluorine have?
10
Atomic mass is equal to
the number of protons plus the number of neutrons (19-9 = 10).
the atomic number is equal to
the number of protons.
The proton, neutron, and electron are
the three main subatomic particles that make up all the elements.
Mass of ~1 amu=
neutron and proton
Mass of ~1/2000 amu=
electron
A covalent bond is one in which
electron pairs are shared
A(n) _____ refers to two or more atoms held together by covalent bonds.
molecule
A molecule is defined as
two or more atoms held together by covalent bonds
A hydrogen atom with a net positive charge is attracted to
an oxygen atom with a net negative charge.
What name is given to the bond between water molecules?
hydrogen
Atoms with the same number of protons but with different electrical charges _____.
are different ions
An ionic bond involves
an attraction between ions of opposite charge
The tendency of an atom to pull electrons toward itself is referred to as its _____.
Electronegativity
