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95 Cards in this Set
- Front
- Back
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What is a tentative answer to a question |
A hypothesis |
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What is a scientific theory |
-A comprehensive explanation supported by abundant evidence -Is much broader than hypothesis |
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What are the three domains of life? |
1.) Bacteria 2.) Archaea 3.) Eukarya |
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Which of the three domains of life have prokaryotic cells? |
-Bacteria and Archaea |
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Which of the three domains of life have eukaryotic cells? |
Eukarya |
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Hypothesis' are __________ and _______________ |
-Testable -Can be proven wrong (falsifiable) |
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What does prokaryotic mean |
Before nucleus (simple cell) |
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Which prokaryotic cell can survive in extreme temperatures? |
Archaea |
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What do a tree, a mushroom and a human have in common? |
They all have DNA |
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What is evolution? |
The process of change that has transformed life on Earth |
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What is the scientific explanation of unity and diversity of life? |
Descent with modification (changes via natural selection) |
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What is a zygote? |
A fertilized egg |
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What is your very first cell? |
The zygote (fertilized egg) |
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What is the chemical material on genes? |
DNA |
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What are the units of inheritance that transmit information from parent to offspring? |
Genes |
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What are DNA's four molecules?
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A, G, C, and T |
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What is the entire set of genetic information that an organism inherits?
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It's genome |
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Thenucleus of each human cell contains a genome that is about ______ chemicalletters long |
3 billion |
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Life is made possible by _________ and _________ |
1.) the input of energy (mostly from sun) 2.) the transformation of energy from one form to another |
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Most ecosystems are ______ powered |
solar |
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Plants and other photosynthetic organisms are called what? |
Producers |
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What do plants and other producers do? |
1.) Capture the energy as sunlight 2.) Convert it |
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Now do plants convert energy? |
They store it as chemical bonds within sugars and other complex molecules |
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Organisms are composed of ______ |
Matter |
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What is matter? |
Anything that takes up space and has mass |
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What is a substance that cannot be broken down to other substances by chemical reactions? |
An element |
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What is a substance consisting of two or more elements in a fixed ration? |
A compound |
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About ___ of the 92 elements are essential to life |
25 |
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What are the four elements that make up 96% of living matter? |
1.) Carbon 2.) Hydrogen 3.) Oxygen 4.) Nitrogen |
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What are required by an organism in minute quantities? |
Trace elements |
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What are some examples of trace elements? |
-Iodine (I) -Iron (Fe) |
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What is the smallest unit of matter that still retains the properties of an element? |
An atom |
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What are atoms composed of? |
Subatomic particles (neutrons, protons, electrons) |
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What charge do neurons have? |
No electrical charge |
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What charge do protons have? |
Positive charge |
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What charge do electrons have? |
Negative charge |
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Neutrons and protons form the __________?
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Atomic nucleus |
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Neutron mass and proton mass are measured in _____ |
daltons |
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How do you know an elements atomic number? |
It's the number of protons |
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How do you know an elements mass number? |
Protons + neutrons |
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How do you know an elements atomic mass? |
Same as mass number (protons + neutrons) |
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What are two atoms of an element that differ in number of neutrons? |
Isotopes |
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What kind of isotopes decay spontaneously, giving off particles and energy? |
Radioactive isotopes |
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What is the attraction between atoms called? |
Chemical bond |
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What are the different types of chemical bonds? |
1.) Covalent 2.) Ionic or electrovalent 3.) Hydrogen |
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Which chemical bond results from sharing of electrons? |
Covalent bond |
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Which chemical bond results from transfer of electrons? |
Ionic Bond |
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What chemical bond results between hydrogen atom of one molecule and an electronegative atom of another molecule? |
Hydrogen bond |
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What consists of two or more atoms held together by covalent bonds? |
A molecule |
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What is the sharing of one pair of valence electrons? |
A single bond |
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What is the sharing of two pairs of valence electrons? |
A double bond |
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Bonding capacity is called the atom's _______ |
valence |
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What is an atom's attraction for the electrons in a covalent bond? |
Electronegativity |
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The more electronegative an atom, the more ________ it pulls shared electrons toward itself |
Strongly |
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What kind of bond is it when the atoms share the electron equally? |
Nonpolar covalent bond |
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What kind of bond is it when one atom is more electronegative and the atoms do NOT share the electron equally? |
Polar covalent bond |
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What is an example of unequal sharing of electrons that cause a partial positive or negative charge for each atom? |
Water molecule |
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A charged atom (or molecule) is called ______ |
an ion |
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A ________ is a positively charged ion |
cation |
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An ________ is a negatively charged ion |
anion |
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What is the attraction between an anion and a cation? |
Ionic bond |
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Compounds formed by ionic bonds are called |
Ionic compounds, or salts (NaCl) |
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Most of the strongest bonds in organisms are ________ that form a cell's molecule |
Covalent bonds |
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In living cells, electronegative partners for a hydrogen bonds are usually _____ or ______ atoms |
1.) Oxygen 2.) Nitrogen |
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All living organisms require ____ more than any other substance |
water |
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Cells are about _____% water |
70-90% |
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The water molecule is a ________ molecule |
polar |
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What is a polar molecule? |
The opposite ends have opposite charges |
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What allows water molecules to form hydrogen bonds with each other? |
Polarity |
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Four of water's properties are... |
1.) Cohesive behavior 2.) Ability to moderate temperature 3.) Expansion upon freezing 4.) Versatility as a solvent |
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What is it called when hydrogen bonds hold water molecules together? |
Cohesion |
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What helps the transport of water against gravity in plants? |
Cohesion |
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What is it called when there is an attraction between two different substances? |
Adhesion |
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What is the measure of how hard it is to break the surface of a liquid? |
Surface tension |
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What do we call the amount of heat that must be absorbed or lost for 1 g of that substance to change its temperature by 1ºC? |
The specific heat of a substance |
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Heat is absorbed when hydrogen bonds _____ |
break |
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Heat is released when hydrogens bond _____ |
form |
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As a liquid evaporates, its remaining surface cools, a process called ______ |
evaporative cooling |
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What helps stabilize temperatures in organisms and bodies of water? |
Evaporative cooling |
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Ice is _____ dense than water |
less |
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Water reaches its greatest density at ___ ºC |
4 |
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What is a liquid that is a homogeneous mixture of substances |
Solution |
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Which bonds have weak charges? |
Hydrogen bonds |
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What is the dissolving agent of a solution? |
Solvent |
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What is the substance that is dissolved? |
Solute |
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What is it called when water is the solvent? |
Aqueous solution |
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Water is a versatile solvent due to its ______ |
Polarity (which allows it to form hydrogen bonds easily) |
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What is the sphere of water molecules that surround an ion when it dissolves in water |
Hydration shell |
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Any substance that adds more H+ ions are called |
Acids (less than 7) |
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Any substance that reduces H+ ions |
Base (more than 7) |
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What is the pH of water? |
7 (neutral) |
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A substance has a pH of 3, is it more acidic or basic? |
Acidic |
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A substance has a pH of 12, is it more acidic or basic? |
Basic |
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What are substances that minimize changes in concentrations of H+ and OH- in a solution |
Buffers |
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Examples of buffers are: |
-Carbonic acid -Sodium hydroxide -Ammonia |
