Exam 1 Flashcards
T or F
all living organisms are composed of multiple cells?
False
some living organisms are single-celled
Place the following levels of biological organization in order from smallest to largest: atom, biosphere, cell, ecosystem, molecule, organ, organism, population, tissue.
Which is the smallest level capable of demonstrating all of the characteristics of life?
atom molecule cell tissue organ organism population ecosystem biosphere
The Cell
Plants use the process of photosynthesis to convert the energy in sunlight to chemical energy in the form of sugar. While doing so, they consume carbon dioxide and water and release oxygen. Explain how this process functions in both the cycling of chemical nutrients and the flow of energy through an ecosystem.
Photosynthesis cycles nutrients by converting the carbon in carbon dioxide into sugar, which is then consumed by other organisms. Additionally, the oxygen in water is released as oxygen gas. Photosynthesis contributes to energy flow by converting sunlight into chemical energy, which is then also consumed by other organisms, and by producing heat.
What is the domain/kingdom?
A foot-tall organism capable of producing its own food from sunlight
Eukarya/Plantae
What is the domain/kingdom?
A microscopic, simple, nucleus-free organism found growing in a riverbed
Bacteria
What is the domain/kingdom?
An inch-tall organism growing on the forest floor that consumes material from dead leaves
Eukarya/Fungi
What is the domain/kingdom?
A thimble-sized organism that feeds on algae growing in a pond
Eukarya/Animalia
How does natural selection cause a population to become adapted to its environment over time?
On average, those individuals with heritable traits best suited to the local environment produce the greatest number of offspring that survive and reproduce. This increases the frequency of those traits over time. The result is the accumulation of evolutionary adaptations.
Best describes the logic of scientific method?
If my hypothesis is correct, I can expect certain test results.
Why is it difficult to draw a conclusion from an experiment that does not include a control group?
Without a control group, you don’t know if the experimental outcome is due to the variable you are trying to test or to some other variable.
Distinguish hypotheses from theories in science
Hypotheses usually are narrow in scope; theories have broad explanatory power.
________ is the core idea that unifies all areas of biology.
Evolution
Natural Selection
Unequal reproductive success
Evolution
Descent with modification
Hypothesis
A testable idea
Biosphere
All life-supporting environments on Earth
How can you tell that something is alive?
You can tell that something is alive because it has the ability to react to its
environment
What are six properties common to all living things?
order regulation growth and development energy utilization reproduction evolution.
What is the basic organization of life?
A cell
What are the three domains of life? What organisms does each domain include?
bacteria – prokaryotic
archaea - prokaryotic
eukarya – eukarya – plantae, fungi, animalia, and protista
What is the theory that unifies biology as a science?
Evolution
Describe the basic steps in the scientific method, using an example. Why are controls
necessary in the scientific method?
The basic steps in the scientific method are observations, question, hypothesis,
prediction, and test. An example of the scientific method is noticing that your car
won’t start, you think it may be your battery, you try jumping your car and you
either realize it is the battery.
Controls are necessary in the scientific method so that they can cancel out any
effects of all variables other than the one being tested.
What is the difference between a hypothesis and a theory?
A theory is a hypothesis
that has been tested multiple times.
An atom can be changed into an ion by adding or removing?
Electrons
An atom can be changed into a different isotope by adding or removing?
Neutrons
If you change the number of ______ the atom becomes a different element.
Protons
A nitrogen atom has 7 protons, and the most common isotope of nitrogen has 7 neutrons. A radioactive isotope of nitrogen has 9 neutrons. What are the atomic numbers and mass numbers of the stable and radioactive forms of nitrogen?
Nitrogen - 14
atomic number of 7
mass of 14
radioactive nitrogen - 16
atomic number of 7
mass of 16
Why are radioactive isotopes useful as tracers in research on the chemistry of life?
Organisms incorporate radioactive isotopes of an element into their molecules just as they do the nonradioactive isotopes, and researchers can detect the presence of the radioactive isotopes.
A sulfur atom has 6 electrons in its third (outermost) shell, which can hold 8 electrons. As a result, it forms _____ covalent bonds with other atoms.
2
What is chemically nonsensical about this structure?
H-C=C-H
Each carbon atom has only three covalent bonds instead of the required four.
Is this a chemical reaction?
Ice melts to form liquid water
NO
A polar molecule is…
Slightly negative at one end and slightly positive at the other end.
Explain how the unique properties of water result from the fact that water is a polar molecule.
The positive and negative poles cause adjacent water molecules to become attracted to each other forming hydrogen bonds. The properties of water such as cohesion, temperature regulation, and water’s ability to act as a solvent.
A can of cola consists mostly of sugar dissolved in water, with some carbon dioxide gas that makes it fizzy and makes the pH less than 7. Describe the cola using the following terms: solute, solvent, acidic, aqueous solution.
The cola is an aqueous solution, with water as the solvent, sugar as the main solute, and CO2 making the solution acidic.
The smallest unit of matter that retains the properties of an element.
Atom
The smallest structural and functional unit of an organism
Cell
All the organisms inhabiting and potentially interacting in a particular area
Community
The global ecosystem; the entire portion of Earth inhabited by life; all of life and where it lives.
Biosphere
All the organisms in a given area
Ecosystem
List properties common to all living things
they are complex and organized
they grow and produce
they respond to stimuli
the acquire materials and use energy (metabolism)
they use DNA to store hereditary information
they have adaptations to their environment
The process of keeping internal conditions such as temperature constant in an organism
homeostasis
A substance that can’t be broken down into another substance by ordinary means
Element
The three components of an atom
Protons +
Neutrons are neutral
Electrons -
These orbit around the protons and neutrons in the nucleus of the atom
Electrons
Equals the number of protons or electron in the element
Atomic number
Equals the number of protons plus its number of neutrons
Atomic mass
____ can donate an electron to another ____ or accept an electron from another ____ to become an ion
Atom
An attraction between two ions with opposite electrical charges. The electrical attraction of the opposite charges holds the ions together.
Ionic bond
An attraction between atoms that share one or more pairs of outershell electrons
Covalent bond
_____ make and break chemical bonds to form new substances.
Chemical bondS
A molecule containing polar covalent bonds
Polar molecule
The shared electrons that form the bond are shared unequally, creating partial positive and partial negative charges at opposite ends of the molecule
Polar covalent bond
A polar molecule composed of two hydrogen atoms and one oxygen atom
water
A weak chemical bond formed when a partially positive hydrogen atom from one polar molecule is attracted to the partially negative atom in another molecule
Hydrogen bond
What are water’s unique properties?
high specific heat good solvent cohesive and adhesive polar ice floats
Water-loving; pertaining to polar or charged, molecules, which are soluble in water
hydrophilic
Water-fearing; pertaining to nonpolar molecules which do not dissolve in water
hydrophobic
What makes a molecule hydrophilic or hydrophobic?
Whether the compound is polar(uneven distribution of charge) or nonpolar (even distribution of charge).
Any solution in which water (H2O) is the solvent
Aqueous
Any aqueous solution which has a pH < 7.0
Acidic solution
An aqueous solution with a pH greater than 7.
basic solution
A measure of the relative acidity of a solution ranging in value from 0 to 14.
pH scare
______ are molecules that minimize changes in pH in an organism.
Buffers
What are the four major classes of large molecules?
Carbohydrates
lipids
proteins
nucleic acids
______ are composed of smaller subunits (monomers)
Large molecules (polymers)
Two subunits covalently bond to each other through the loss of a water molecule in a_______
dehydration reaction
The opposite of a dehydration reaction where a molecule of water is added to break the covalent bond
hydrolysis
______ contain both carbon and hydrogen while _____ do not
Organic molecules
inorganic molecules
Include single sugars (monosaccharides) and molecules made of two or more sugar subunits (disaccharides, polysaccharides)
Carbohydrates
The function of _____ is to store energy
disaccharides
A carb polymer consisting of many monosaccharides linked by covalent bonds
polysaccharide
What are the two main types of polysaccharides?
storage and structural
A large polysaccharide composed of many glucose monomers linked into cable-like fibrils that provide structural support in plant cell walls. Cellulose cannot be digested by animals.
cellulose