Each water molecule is joined to _____ other water molecules by ____ bonds.
The unequal sharing of electrons within a water molecule makes the water molecule _____
The tendency of an atom to pull electrons toward itself is referred to as its _____.
In this molecule, what type of bond is found between the oxygen and hydrogens?
Why isn't this insect drowning?
A(n) ___ is a chemical bond resulting from the attraction between atoms that have acquire a charge due to losing or gaining one or more electrons
A(n)_____is a chemical bond in which two atoms share one or more pairs of valence electrons
A(n)____is a weak chemical bond that is formed when the partially positive hydrogen atom of a polar covalent bond in one molecule is attracted to the partially negative atom of a polar covalent bond in another molecule.
Which statements about hydrogen bonding in water are true?
The hydrogen atoms of a water molecule have a partial positive charge. The hydrogen atom of one water molecule is attracted to the oxygen atom of a different water molecule. The oxygen atom of a water molecule has a partial negative charge.
The oxygen atom of a water molecule is more electronegative than a hydrogen atom.
is a mesure of how difficult is to stretch or break the surface of a liquid
is an attraction between different kinds of molecules
is an attraction between like molecules
-Water molecules cling to plant cell walls -Water molecules cling to the side of a beaker.
-Water molecules are attracted to each other. -A drop of water spilled on a table forms a drop on the table, rather than spreading out over the surface.
-A water strider runs across a pond without breaking the surface. -A sewing needle floats when it is placed gently on top of water in a bucket.
Substance with a high specific heat
-Requires more heat to change the temperature of the substance. -More resistant to temperature change. -Most likely to exhibit hydrogen bonding.
Substance with a low specific heat
-requires less heat to change the temperature of the substance. -less resistant to temperature change -least likely to exhibit hydrogen bonding.
The table shown here lists the specific heat of several substances. Substance Specific heat
water 4.18 ethyl alcohol 2.44 benzene 1.80 sulfuric acid 1.40 Based on the information in the table, which of the following statements are true?
-Sulfuric acid is less resistant to temperature change than water -More heat is required to raise the temperature of 1 g of water 1 than to raise the temperature of 1 g of ethyl alcohol 1 . -Water has a high specific heat due to the hydrogen bonding between water molecules. - Benzene is more resistant to temperature change than sulfuric acid.
What process is illustrated by this animation?
Which term describes the degree to which an element attracts electrons?
Which terms describe two atoms when they form a bond in which electrons are completely transferred from one atom to the other?
Anion and cation
Which of the following statements is true of the bonds in a water molecule?
Oxygen holds electrons more tightly than hydrogen does, and the net charge is zero.
Which of the following statements about the atoms in a water molecule is true?
The oxygen atom in a water molecule has a partial negative charge.
Which modeling method only gives information about the number and identity of atoms in a molecule?
Which of the following statements most accurately describes the phases of water?
The entropy of water is higher than the entropy of ice.
Why does water require so much energy to change its phase?
WATER has a large number of hydrogen bonds
Which statement must be mentioned in explaining why amphipathic molecules line up at a water surface?
Polar groups attract one another.
Dissolving is best described as
a mingling of molecules and/or ions.
Water is a source of ______________ for chemical reactions in cells.
(a) hydrogen atoms (b) oxygen atoms (c) energy Both (a) and (b) (a), (b), and (c).
Both (a) and (b) [ hydrogen atoms, oxygen atoms]
Water has surface tension because ...
hydrogen bonds between surface water molecules resist being stretched
Which of the following helps most to explain why water has a high specific heat?
A water molecule can make 4 hydrogen bonds.
Though you add heat, the temperature of boiling water remains constant because ...
it takes energy to break hydrogen bonds.
Why doesn't oil mix with water?
Polar molecules attract one another.
In a neutral solution the concentration of _____
hydrogen ions is equal to the concentration of hydroxide ions
Which of these is the correct equation for the dissociation of water?
H2O + H2O <==> H3O+ + OH-
What is the charge on a hydronium ion?
What is the charge on a hydroxide ion?
About _____ molecules in a glass of water are dissociated.
1 in 500,000,000
Which answer is a true statement about pH values? Stomach juice has a high pH. pH is important in life mainly because it affects the cohesion of water. A high pH corresponds to a high H+ concentration. Pure water has a pH of 0. None of the above.
None of the above
What conditions must be met in order for an aqueous solution to be called "neutral"?
The concentrations of hydronium and hydroxide ions are equal.
Factory smoke has led to acid rain that lowered the pH of a lake to 5.0. What is the H+ concentration in the lake?
10- 5 M
Your tank of swamp fish needs a pH of 5, and the pH is 7 at present. What should you do to the H+ concentration?
Raise it to 100 times its present value
In a washing machine, the detergent raised the pH to 9.0. The concentration of OH- in the solution is
Your tank of alkali fish needs a pH of 8, and the pH is 6 at present. What should you do to the H+ concentration?
Reduce it to 1/100 of its present value.
Which of the following is a correct match of cell type with structure?
muscle cell ... has proteins that slide back and forth
Suppose that Zonosemata flies whose own wings had been clipped and reattached were attacked more frequently than untreated Zonosemata flies. How would this result affect the reliability of the other experimental results?
All results for the experimental groups involving wing surgery would be invalid
What results from the Zonosemata experiment support the sub-hypothesis that wing waving alone reduces predation by jumping spiders?
Zonosemata flies with housefly wings are attacked less frequently.
In Pasteur's experiment to test the hypothesis of spontaneous generation, why did he boil the broth in both flasks?
To kill any existing organisms in the broth
Which of the following variables did Pasteur change in his experiment to test the hypothesis of spontaneous generation?
The shape of the flask
Which of the following statements is true of a hypothesis?
A hypothesis can be supported or rejected through experimentation.
Which of the following statements could not be supported or rejected by a scientific experiment?
The first living cell on Earth came from outer space
In an experiment, investigators try to control all of the variables except one—the one that tests the hypothesis. Which of the following reasons is the primary rationale for controlling variables in an experiment?
To eliminate alternative explanations for the results of an experiment
Which of the following statements is not true of scientific experiments?
They must occur under carefully controlled conditions found in a laboratory.
What are the two main types of cells?
prokaryotes and eukaryotes
Which of these is an organ system?
An organ, such as the liver, is composed of _____.
Between 1966 and 1995, what has been the approximate decrease in stream flow rates in Monteverde?
Stream flow rates have apparently been decreasing worldwide since 1966.
Cannot tell from graph
It would have been reasonable to place stream flow on the X-axis instead of year.
Since the points don't form a straight line, it would have been better to draw this as a scatter plot.
Even though they live in the same location, these two species probably experience minimal competition for food.
The sooty tern consumes more fish than the blue-grey noddy tern.
Cannot tell from the graph
For the sooty tern, there is a steady decrease in the percent of diet as fish length decreases from 6 cm to 0 cm.
For what sizes of fish is there the least amount of overlap in the diets of these two tern species?
greater than 6 cm
For the graph in Step 7 showing fish body lengths and the percentage of tern diets that they comprise, which statement best summarizes the trend shown in the graph?
The blue-grey noddy's diet is composed primarily of smaller fish and the sooty tern's diet is composed mostly of moderate sized fish.
Greater abundance of tree and bush stems results in higher birth rates for snowshoe hares.
Cannot tell from graph
Increasing density of tree and bush stems has a positive effect on snowshoe hare abundance.
As stem density increases from about 35,000 stems to about 55,000 stems per hectare, what is the increase in snowshoe hare density?
1 hare per hectare
For the graph of data on stem density and snowshoe hare density in Step 6, which statement best summarizes the trend shown in the graph?
The density of hares increases as the density of stems increases.
hat should you do next?
Perform experiments to test your hypothesis.
Which of the following experiments would best test your hypothesis?
Find other people born in the same week and ask them what their favorite type of movie is.
What should you do next?
Refine your hypothesis.
In eukaryotic cells DNA has the appearance of a _____.
DNA is composed of building blocks called
Which statement helps most to explain why life is based on carbon compounds?
C-C bonds are as strong as C-O bonds.
L-dopa is used to treat
What kind of effect does R-dopa have on Parkinson's disease?
Enantiomers are molecules that
are mirror images
Geometric isomers are molecules that _____.
differ in the arrangement of their atoms about a double bond
is highly polar and may act as a weak acid
Carboxylic acid (H-O-C=O)
acts as an acid (DONATES IONS)
aldehyde (O=C)/ Carbonyl group
may be a structural isomer of a ketone
forms disulfide bonds sulfhydryl group
acts as a base
Organic Phospahte P03
CONTRIBUTES NEGATIVE CHARGE COMPONENT OF ATP
Which of the following statements about neutrons is false?
The neutron is positively charged.
Which of the following statements about protons is false?
The proton is found outside the nucleus of an atom
Which of the following statements about electrons is false?
The electron is electrically neutral.
Symbol: P Charge :1+
Symbol: n, Charge: 0
Symbol: e Charge: 1-
mass of ~1amu
mass of ~1/2000 amu
What is the mass number of an ion with 105 electrons, 157 neutrons, and a +1 charge?
263 ( add them)
The innermost electron shell of an atom can hold up to _____ electrons.
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
What is the atomic number of an atom that has 6 protons, 6 neutrons, and 6 electrons?
Which of these refers to atoms with the same atomic number but different atomic masses?
These atoms are isotopes
Fluorine's atomic number is 9 and its atomic mass is 19. How many neutrons does fluorine have?
An uncharged atom of boron has an atomic number of 5 and an atomic mass of 11. How many protons does boron have?
A(n) _____ refers to two or more atoms held together by covalent bonds.
What name is given to the bond between water molecules?
Atoms with the same number of protons but with different electrical charges _____.
are different ions
In salt, what is the nature of the bond between sodium and chlorine?
An ionic bond involves _____.
an attraction between ions of opposite charges
What type of bond joins the carbon atom to each of the hydrogen atoms?
single (nonpolar) covalent
A water sample from a creek contained a single-celled organism that had both a cell membrane and a nucleus. What is its most likely classification?
The main source of energy for producers in an ecosystem is
Often a metabolic pathway is regulated by the production of the end product, such that as the end product accumulates, the pathway is turned off. This is an example of
Which of the following are not considered "living", and cannot perform all the activities required for life?
organelle - for example, a chloroplast
Prokaryotic and eukaryotic cells have which of the following features in common?
a plasma membrane
Which of the following sequences represents the hierarchy of biological organization from the least to the most complex level?
molecule, cell, organ system, population, ecosystem, biosphere
Prokaryotes are classified as belonging to two different domains. What are the domains?
Two species that belong to the same class must also belong to the same
Which of the following types of cells do not utilize deoxyribonucleic acid (DNA) as their genetic material?
Which of the following statements concerning prokaryotic and eukaryotic cells is not correct?
Which of the following statements is false?
The neutrons and electrons present in the nucleus of an atom are almost identical in mass; each has a mass of about 1 dalton.
Each element is unique and different from other elements because of the number of protons in the nuclei of its atoms. Which of the following indicates the number of protons in an atom's nucleus?
The atomic number of each atom is given to the left of each of the elements below. Which of the atoms has the same valence as carbon (6C)?
How many electrons does an atom of sulfur have in its valence shell?
Which of the following best describes the relationship between the depicted atoms?
They are both isotopes of phosphorus.
Electrons exist only at fixed levels of potential energy. However, if an atom absorbs sufficient energy, a possible result is that
an electron may move to an electron shell farther out from the nucleus.
What results from an unequal sharing of electrons between atoms?
a polar covalent bond
Which of the following is not considered to be a weak molecular interaction?
a covalent bond
What is the approximate atomic mass of an atom with 16 neutrons, 15 protons, and 15 electrons?
The nucleus of a nitrogen atom contains 7 neutrons and 7 protons. Which of the following is a correct statement concerning nitrogen?
The nitrogen atom has a mass number of 14 and an atomic number of approximately 7 daltons.
Natural selection tends to act at which of the following levels
The ability of water molecules to form hydrogen bonds with other water molecules and water's ability dissolve substances that have charges or partial charges are
both caused by water's partial charges
In the term trace element, the adjective trace means that
the element is required in very small amounts.
For most atoms, a stable configuration of electrons is attained when the atom
has eight electrons in its outermost shell
Which of the following is an attribute of living things?
they must be able to evolve and adapt
The energy used by most organisms for metabolism and growth ultimately comes from
Phosphorus-32 radiactive has___ than phosphorus 35
3 fewer neutrons
Measurements show that the PH of a particular lake is 4.0 What is the hydrogen ion concentration of the lake?
Ethanol, propanol and methanol are three simple alcohols. They can be grouped together because they____
all share the same functional group: Hydroxyl
WHich of these is a trace element
What are the 4 most abundant elements found in living systems?
Ionic Bonds form as a result of
attraction between ions that have opposite charges
There are ___ naturally occurring elements
What do cohesion, surface tension, and adhesion have in common with reference to water?
all are properties related to hydrogen bonding
Which action could produce a carbonyl group?
the replacement of the -OH of a carboxyl group with hydrogen
Which of the following is the fundamental unit of structure and function in living organisms?
A molecule that has all nonpolar covalent bonds would be
A hydrogen bond
is a weak chemical bond
Isotopes of an element will always differ in
The first organic molecule to be synthesized from inorganic substances that could be prepared directly from inorganic substances was
The bonds that are broken when water vaporizes are
hydrogen bonds between water molecules
A controlled experiment is one that
test experimental and control groups in parallel
System Biology is mainly an attempt to
understand the behavior of entire biological systems
Protists and bacteria are grouped into different domains because
protist have a membrane-bounded nucleus, which bacterial cell lack
Sequencing a protein to discover the sequence of amino acids that make it up is an example___ Understanding how that protein works with other proteins in a cell is an example of ___
What is the appropriate term for an interacting group of individuals of a single type occupying a defined area?
When the proton number and electron number are unequal the atom or molecule
is an ion
Stanley Miller's experiment were significant because he demostrated that
a variety of simple organic compounds could be spontaneously synthesized from components in Earth's primitive atmosphere.
Adding a base tends to ____ of a solution
lower the hydrogen ion concentration and increase the PH
Emergent properties of living systems are defined as properties that
are due to the arrangement and interaction of parts as complexity increases
What are the 6 most important chemical elements of life
Which of the following are properties of hydrocarbons
hydrophobic nonpolar good source of stored energy
A straight chain carbon compound constructed from____must contain at least one carbon-carbon double bond
An acid is ___
a compound that donates hydrogen ions to a solution
Why does ice float in liquid water?
Hydrogen bonds stabilize and keep the molecules of water farther apart than the water molecules of liquid water.
A solution contains 0.00001(10-5) moles of hydroxyl ions [OH-] per liter. Which of the following best describes this solution?
Basic H+ acceptor
What gives rise to water molecules' ability to moderate air temperature?