What is the difference between a tissue and an organ system?
All living things are composed of cells, and a group of cells form tissues. These tissues combine to form organs, and the organs form an organ system. The tissues perform simpler tasks, whereas the organs perform the complex functions of the body.
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The tree in your backyard is home to two cardinals, a colony of ants, a wasp's nest, two squirrels, and millions of bacteria. Together, all of these organisms represent
a community
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If you eat a hamburger, you are mainly eating ground-up beef muscle. What levels of organization are represented in this ground-up muscle?
organelle, cell and tissue
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Which of the following statements regarding a common cellular activity is false?
new cells are derived from cellular components like organelles
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Your instructor asks you to look into your microscope to see a prokaryotic cell. You will be looking for a cell that
has a membrane
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Organisms that are prokaryotes are in the domains
Bacteria and Archaea
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Which of the following statements about the domain Bacteria is true?
All bacteria lack a nucleus
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Which of the following is a kingdom within the domain Eukarya?
Fungi
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Plantae, Animalia, Fungi and Protista.
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You notice that over the past month, many students on campus have started wearing a new style of school sweatshirt. You think to yourself that perhaps the bookstore has recently started selling this new sweatshirt style. This prediction is an example of
a hypothesis
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To be scientifically valid, a hypothesis must be
testable and falsifiable
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The role of a control in an experiment is to
baseline, rules out the independent variable
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The National Institutes of Health (NIH) set up a study to determine whether large doses of vitamin C would shorten the length of time it takes to recover from a cold. Three thousand volunteers were split into two groups. For two weeks, members of Group A took 3,000 mg of vitamin C daily. Group B received 3,000 mg of a placebo. At the end of the two-week period, the researchers inserted live cold viruses directly into the noses of all the volunteers. The volunteers in both Group A and B continued to take their daily pills. All the volunteers got colds, and there was no significant difference in the length of time the colds lasted. Which was the experimental group?
Group A
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To have confidence that the results of the experiment were valid, you'd also want to know
whether any volunteers had colds (were sick) at the start of the experiment.
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The four most common elements in living organisms are
hydrogen, oxygen, nitrogen, and carbon
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Which of the following statements regarding matter is false?
All matter exists in the form of compounds
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Which of the following particles is found in the nucleus of an atom?
protons and neutrons
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Electrons move about the nucleus of an atom in the same way that
insects fly around a bright lamp at night
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An uncharged atom of boron has an atomic number of 5 and an atomic mass of 11. How many electrons does boron have?
5 electrons
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Which of the following best describes the atomic number of an atom?
number of protons in an atom
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When full, the innermost electron shell of argon contains \________ electrons, and the outermost shell contains \________ electrons.
2 on the inner and 8 on the outer
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A(n) \________ forms when two atoms share electrons.
covalent bond
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A hydrogen atom has one electron. How many covalent bonds can hydrogen form?
1 covalent bond
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Table salt is formed when
sodium (Na) and chloride (Cl) have an ionic bond to make NaCl, table salt
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What is the fundamental difference between covalent and ionic bonding?
Ionic bonding is giving/taking electrons to atoms and then ions are created which are bonded together. covalent bonding is the sharing of electrons between atoms
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Which of the following statements regarding the oxygen atom of a water molecule is true?
oxygen is more electronegative than the hydrogen atoms
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In a water molecule, hydrogen and oxygen are held together by a(n) \________ bond.
polar covalent bonds
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The hydrogen atoms of a water molecule are bonded to the oxygen atom by \________ bonds, whereas neighboring water molecules are held together by \________ bonds.
polar covalent, hydrogen
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\________ are weak bonds that are not strong enough to hold atoms together to form molecules but are strong enough to form bonds within and around large molecules.
hydrogen bonds
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Water molecules stick to other water molecules because
hydrogen bonds form between the hydrogen atoms of one water molecule and the oxygen atoms of other water molecules
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The tendency of water molecules to stick together is referred to as
cohesion
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Water's surface tension and heat storage capacity is accounted for by its
hydrogen bonds
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Which of the following statements about water is false?
ice is denser than liquid water
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A solution with a pH of 7 is
neutral
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Compared to a solution of pH 3, a solution of pH 1 is
100 times more acidic
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Which of the following statements about pH is true?
An increase in hydrogen ion concentration means a decrease in pH scale units or vice versa
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A pharmaceutical company hires a chemist to analyze the purity of the water being used in its drug preparations. If the water is pure, the chemist would expect to find
H2O molecules, H+ ions, and OH- ions.
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You've made a hot drink by dissolving a teaspoon of instant coffee and a teaspoon of sugar in a cup of hot water. Which of the following statements is true?
you've just prepared an aqueous solution
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As ice melts,
Hydrogen bonds are broken and the resulting liquid is more dense
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organic compounds
always contain carbon
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Which of the following statements regarding carbon is false?
carbon has the ability to bond with up to 6 atoms
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Which of the following statements about hydrocarbons is false?
Hydrocarbons are inorganic compounds.
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Propanol and isopropanol are isomers. This means that they have
same structure and formula, different function and properties
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Which of the following is a carboxyl group?
COOH
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Which of the following is an amino group?
NH2 (2 is a subscript)
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Which of the following statements about the functional groups of organic compounds is false?
All functional groups contain a carbon atom
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Which of the following contains a carboxyl and an amino group?
amino acid
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Which of the following statements about the monomers and polymers found in living organisms is false?
monomers are joined together by the process of hydrolysis
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Which of the following statements about dehydration synthesis is false?
Animal digestive systems utilize this process to break down food and large macromolecules
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The results of dehydration synthesis can be reversed by
hydrolysis (adding water)
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Which of the following is a carbonyl group?
CO
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Which of the following is a hydroxyl group?
OH
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Which of the following is a methyl group?
CH3
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Which of the following is a phosphate group?
PO4
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The molecular formula of most monosaccharides represents a multiple of
CH2O
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A molecule with the formula C55H110O55 is probably a(n)
polysaccharides
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Many names for sugars end in the suffix
-ose
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A disaccharide forms when
2 monosaccharides join by dehydration synthesis
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Which of the following lists contains only polysaccharides?
cellulose, starch, glycogen
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Foods that are high in fiber are most likely derived from
plants
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The storage form of carbohydrates is \________ in animals and \________ in plants.
glycogen in animals and starch in plants
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An oil may be converted into a substance that is solid at room temperature by
Adding more hydrogen(hydrogenation)
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What features of fats make them hydrophobic?
A long hydrocarbon hydrophobic chain
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Fatty acids are...
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Which of the following statements regarding triglyceride molecules is false?
Triglycerides are hydrophilic.
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Fatty acids with double bonds between some of their carbons are said to be
unsaturated
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Which of the following statements about animal cell lipids is false?
many lipids function as enzymes
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A phospholipid is composed of
two fatty acids, a glycerol unit and a phosphate group
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hydrophilic phosphate head and two hydrophobic fatty acid tails
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A major type of lipid found in cell membranes is
phospholipids
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Amino acids can be distinguished from one another by?
Chemical properties of the R-group
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Proteins differ from one another because
specific amino acid sequence
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Glucose molecules are to starch as \________ are to proteins.
amino acids
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peptide bonds
link amino acids
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Which of the following statements about enzymes is false?
monomers to build build proteins
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Which one of the following would be correctly classified as a protein?
enzymes
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Which of the following characteristics of protein will remain intact if the protein is denatured?
amino acid sequence
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Proteins cannot be denatured by
freezing
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The primary structure of a protein is
amino acid sequence
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Which of the following is an example of secondary structure in a protein?
beta pleated sheet or alpha helix
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The tertiary structure of a polypeptide refers to
3D shape
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A protein containing more than one polypeptide chain exhibits the \________ level of protein structure.
Quaternary structure
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How are genes used by cells to build proteins?
DNA to RNA to Proteins
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Which of the following statements regarding nucleotides is false?
Lipid
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You work for a company that manufactures food products. A new "wonder food" is being distributed by a rival company. The researchers in your company determine that the "wonder food" contains only carbon, oxygen, and hydrogen. At this point, your researchers can say with certainty that the food
does not include proteins or nucleic acids
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Which of the following statements about cells is true?
All cells have internal structures that move.
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Light microscopes
use light and glass lenses to magnify an image.
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Resolution is the
ability of an optical instrument to show two close objects as separate
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Which of the following statements about electron microscopes is true?
Electron microscopes focus electron beams to create a magnified image of an object.
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The idea that all living things are composed of cells and that all cells come from other cells defines
Cell theory
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A scanning electron microscope is used to study \________, whereas a transmission electron microscope is used to study \________.
cell surfaces; internal cell structures
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Which of the following structures is exclusively associated with prokaryotic cells?
nucleoid
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The nucleoid region of a prokaryotic cell
contains the cell's DNA.
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Unlike animal cells, plant cells have \________ and \________. Unlike plant cells, animal cells have \________.
chloroplasts; cell walls; centrioles
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You are told that the cells on a microscope slide are plant, animal, or bacterial. You look at them through a microscope and see cell walls and membrane-bound organelles. You conclude correctly that the cells
Are plant cells
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The two main functions of the rough endoplasmic reticulum are the production of
membrane and proteins secreted by the cell.
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The Golgi apparatus
stores, modifies, and packages proteins.
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Which of the following statements about lysosomes is false?
Lysosomes synthesize proteins from the recycled amino acids.