1What is scientific inquiry?
A deliberate way of asking and answering questions about the natural world
2What is a hypothesis?
A tentative explanation that makes predictions that can be tested
3How do scientists test hypotheses?
By designing experiments or making further observations
4What is a controlled experiment?
An experiment where all conditions are the same except for one deliberately changed variable
5What are the main steps of scientific inquiry?
Observation, questioning, testing, and sharing conclusions
6When does a hypothesis become a theory?
When it is supported by extensive evidence over long periods of time
7What is a scientific theory?
A broad, well-supported explanation of an aspect of the natural world
8How do chemistry and physics relate to life?
Living and nonliving things follow the same chemical and physical laws
9What did Redi and Pasteur demonstrate?
That organisms come from other organisms and not spontaneous generation
10What is spontaneous generation?
The incorrect idea that life arises from nonliving matter
11When did life originate on Earth?
About 4 billion years ago
12How did life originate?
From nonliving matter through natural chemical processes
13What is the fundamental unit of life?
The cell
14What is the cell membrane?
The boundary that separates the cell from its environment
15What is the difference between prokaryotic and eukaryotic cells?
Eukaryotic cells have a nucleus while prokaryotic cells do not
16What molecule stores genetic information?
DNA
17What is the central dogma of biology?
The flow of information from DNA to RNA to protein
18What is metabolism?
The chemical reactions that build and break down molecules and manage energy
19What is evolution?
A change in a population over time due to inherited variation
20What conditions are required for evolution?
Variation and inheritance
21What is the ultimate source of genetic variation?
Mutation
22What does a nested pattern of similarity show?
Shared evolutionary ancestry
23Can evolution be demonstrated experimentally?
Yes
24What is ecology?
The study of interactions between organisms and their environment
25At what scales do ecological systems exist?
From local environments to the entire Earth
26How does evolution influence ecological systems?
Through organism traits such as anatomy, physiology, and behavior
27What is the human footprint?
The impact humans have on ecology and evolution
28How long have modern humans existed relative to life on Earth?
Only a very small fraction of Earth’s history
29Why do biological problems require multiple scientific fields?
Because life is complex and interconnected
30What is an atom?
The fundamental unit of matter
31What particles make up an atom?
Protons, neutrons, and electrons
32What determines the identity of an atom?
The number of protons
33What determines atomic mass?
The number of protons and neutrons
34What determines atomic charge?
The balance of protons and electrons
35Where are electrons found?
In orbitals around the nucleus
36What does the periodic table represent?
Patterns in chemical behavior of elements
37What is a molecule?
Two or more atoms bonded together
38What are valence electrons?
Electrons in the outermost shell that determine bonding
39What is a covalent bond?
A bond formed by sharing electrons
40What is a polar covalent bond?
A bond with unequal sharing of electrons
41What is electronegativity?
An atom’s ability to attract electrons
42What is an ionic bond?
Attraction between oppositely charged ions
43Why is water polar?
Because electrons are shared unequally between oxygen and hydrogen
44What does hydrophilic mean?
Water-attracting
45What does hydrophobic mean?
Water-repelling
46What is a hydrogen bond?
A weak interaction involving a hydrogen atom and an electronegative atom
47What properties of water are due to hydrogen bonding?
Cohesion, surface tension, and temperature stability
48What does pH measure?
The acidity of a solution
49Why is carbon important in biology?
It forms the backbone of organic molecules
50How many bonds can carbon form?
Four covalent bonds
51What are the four major classes of organic molecules?
Proteins, nucleic acids, carbohydrates, and lipids
52What are proteins made of?
Amino acids
53What determines amino acid properties?
The R group
54What are nucleic acids made of?
Nucleotides
55What are the components of a nucleotide?
A sugar, base, and phosphate group
56What sugar is found in DNA?
Deoxyribose
57What sugar is found in RNA?
Ribose
58What are pyrimidines?
Cytosine, thymine, and uracil
59What are purines?
Guanine and adenine
60What are carbohydrates used for?
Energy
61What are lipids?
Hydrophobic molecules
62What are triacylglycerols used for?
Energy storage
63What is a fatty acid?
A hydrocarbon chain with a carboxyl group
64What is the difference between saturated and unsaturated fatty acids?
Presence or absence of double bonds
65What force helps pack fatty acids tightly?
van der Waals forces
66What did the Miller–Urey experiment show?
That amino acids can form under early Earth conditions
67How could early polymers form?
On clay mineral surfaces
68What is the cell theory?
All organisms are made of cells, cells are the fundamental unit of life, and cells come from preexisting cells
69What defines prokaryotic cells?
Lack of nucleus and membrane-bound organelles
70What organisms are prokaryotes?
Bacteria and archaea
71What defines eukaryotic cells?
Presence of nucleus and organelles
72What organisms are eukaryotes?
Animals, plants, fungi, and protists
73What are cell membranes made of?
Lipids, proteins, and carbohydrates
74Why do phospholipids form bilayers?
They have hydrophilic heads and hydrophobic tails
75What does membrane fluidity mean?
Components move laterally
76What affects membrane fluidity?
Fatty acid length, double bonds, cholesterol, and temperature
77What are transmembrane proteins?
Proteins that span the membrane
78What are peripheral proteins?
Proteins attached to one side of the membrane
79What is passive transport?
Movement from high to low concentration without energy
80What is facilitated diffusion?
Passive transport using proteins
81What is active transport?
Movement against a concentration gradient requiring energy
82What uses ATP directly?
Primary active transport
83What uses an electrochemical gradient?
Secondary active transport
84What helps maintain cell shape in plants and bacteria?
Cell wall
85What internal structure helps maintain cell shape?
Cytoskeleton
86What is the endomembrane system?
A network of interconnected membranes in eukaryotic cells
87What organelles are part of the endomembrane system?
Nucleus, ER, Golgi, lysosomes, vesicles, cell membrane
88What is the function of the nucleus?
Houses the genome
89What does the ER do?
Synthesizes proteins and lipids
90What is the role of the Golgi apparatus?
Sorts and directs proteins and lipids
91What do lysosomes do?
Break down macromolecules
92What is the function of mitochondria?
Energy production
93What is the function of chloroplasts?
Photosynthesis
94What is the origin of mitochondria and chloroplasts?
Endosymbiosis
95What is the cytoskeleton?
A network of protein filaments that maintain cell shape
96What are the three cytoskeletal components?
Microfilaments, intermediate filaments, microtubules
97What are microfilaments made of?
Actin
98What are intermediate filaments made of?
Cell-type-specific proteins
99What are microtubules made of?
Tubulin dimers
100Which cytoskeletal elements are dynamic?
Microfilaments and microtubules
101What motor protein works with microfilaments?
Myosin
102What motor proteins work with microtubules?
Dynein and kinesin
103What are cilia?
Microtubule-based projections from the cell surface
104What do motile cilia do?
Move cells or surrounding fluid
105What do nonmotile cilia do?
Serve sensory functions
106Do prokaryotes have cytoskeletal elements?
Some have similar protein polymers