Experiments are carried out to test the hypothesis by changing one variable at a time and including a ______ conditioin in which the variable is unaltered. |
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control |
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Biological order has _____ organization, from the level of highly structured organic molecules in the cells to the highest level of populations and communities in biomes and biosphere. |
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hierarchical |
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The method of reasoning that constructs general principles by careful examination of many specific cases is called: |
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inductive reasoning |
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A hypothesis can be tested with: |
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an experiment |
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After making careful observations, scientists construst a _____. |
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hypothesis |
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Hypotheses: |
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do NOT always withstand the test of experiments |
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Darwin descreibed __________ _________ as "those individuals that possess superior physical, behavioral, or other attributes are more likely to survive than those that are not so well endowed," and thus more likely to pass their traits to the next generation. |
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natural selection |
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Modern pieces of evidence that corroborate Darwin's theory of evolution include: |
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1. New meansurements of the age of earth
2. An understanding of the mechanism of heredity
3. Comparative studies of animal structures
4. Similarities in DNA of related species |
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A critical requirement of Darwin's theory is: |
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genetic variation exists in nature |
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THe same basic array of bones is modified to give rise to the wing of a bat and the fin of a porpoise. Such anatomical structures are called |
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homologous |
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A medical scientist is designing an experiment to test the results of a new drug that she hypothesizes will greatly reduce and possibly eliminate the side effects of a new cancer treatment. If this experiment is to be set up correctly, she must: |
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divide the patients into two groups and give one group the new drug and the other group a drug that has no effect. |
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Hierarchicial organization in living organisms: |
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molecule>cell>organ>population>community |
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The cell theory DOES include: |
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cells arise from other cells through the process of cell division,
cells carry genetic material passed to daughter cells during cellular division,
and energy flow (metabolism and biochemistry) occurs within cells. |
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All of the substances of the universe that have mass and occupy space are defined as |
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matter |
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The number of protons in a given atom is equal to its ______ number. |
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atomic |
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Isotopes that decay with a nuclear break-up and emit a significant amount of energy are said to be |
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radioactive |
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______ is defined as the negative logarithm of the hydrogen ion concentration in the solution. |
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pH |
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A substance that interacts with H+ ions in solution, opposing any increase or decrease in concentration is a |
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buffer |
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Atoms are composed of electrons and a dense nucleus which contains protons and |
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neutrons |
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Negatively charged particles of atoms with almost no mass are called |
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electrons |
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Elements that have atoms with the same atomic numbers but different number of neutrons are called: |
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isotopes |
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In chemical redox reactions, the gain of an electron is called |
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reduction |
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When atoms gain or lose electrons, they become negatively or positively charged. They are known as |
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ions |
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When two atoms share a pair of electrons, the bonding is referred to as |
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covalent |
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Water molecules are polar with ends that exhibit partial positive and negative charges. Such opposite charges make water molecules attract each other through |
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hydrogen bonds |
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True statements about electrons: |
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1. an electron has onenegative charge
2. the mass of an electron is neglible
3. electrons are found in an area around the nucleus, called the orbital |
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Regardless of its shape (spherical or dumbbell), a given orbital may contain no more than |
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2 electrons |
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Na has 11 electrons arranged in 3 energy levels. The outer level has only 1 electron. In order to become stable, the atom loses an electron thus exposing the previous (lower) level with 8 electrons and subsequently becomes an ion with: |
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1 positive charge |
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In the crystal matrix of ordinary salt, the sodium and the chloring are held together by |
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ionic bonds |
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Because oxygen is more electronegative than hydrogen, the water molecule is |
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polar |
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Two carbon atoms might be joined to each other by the sharing of two pairs of elctrons, forming a |
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double bond |
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Compared with a pH of 7, a solution of pH 5 has |
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100 times the hydrogen concentration |
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Three of the four macromolecules present in living systems are _____, which means they are built by linking together small, similar chemical components. |
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polymers |
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Proteins that can carry out catalysis in organisms are called _____. |
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enzymes |
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A modified form of cellulose found in the exoskeletons of insects and crstaceans is known as _______. |
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chitin |
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Macromolecules are disassembled in ______ reactions. |
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hydrolysis |
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All of the following are examples of functional groups in cells: |
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CH3
COOH
NH2
OH |
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Nucleic acids are polymers formed of building blocks that contain |
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rings of nitrogen bases |
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Proteins are involved in all of the following functions: |
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structure, metabolism, membrane transport, and muscle contraction |
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Functional groups found in amino acids involved in peptide bonds are |
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COOH and NH2 |
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Alpha helix and beta pleated sheets are examples of which level of protein structure? |
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secondary |
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The information storage molecules of cells are called |
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nucleic acids |
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Imagine that you were able to see a nucleotide under a very special microscope. As you scan the nucleotide, you see a T nitrogen base. Without seeing any other part of the nucleotide you know that |
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it is a DNA nucleotide |
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Glycosydic linkages are involved in forming macromolecules known as |
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carbohydrates |
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Examples of monomer: polymer pairing: |
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1. amino acids: polypeptides
2. monosaccharides: polysaccharides
3. nucleotides: DNA
4. glucose: starch
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Nucleic acids are created with |
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phosphodiester bonds |
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The "amino end" and the "carboxyl end" of a macromolecule refer to |
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protein |
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The 5' end and the 3' end of a macromolecule refer to |
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DNA |
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