Bio
Absolutely. I’ll make these college-level BIOSC 0150 flashcards, meaning they’ll test mechanisms, relationships, prediction, quantitative reasoning, and application, not just definitions.
I’m using your Lecture 1 + Lecture 2 files and the learning objectives you pasted. The lecture explicitly emphasizes atoms, periodic-table organization, bonding, water properties, moles/molarity, pH, and buffers.
Lecture_2_Chemistry+of+life.pdf
BIOSC 0150 — IN-DEPTH FLASHCARDS
Unit 1: Characteristics of Life + Chemistry of Life
PART I — CHARACTERISTICS OF LIFE
Your Lecture 1 identifies the major themes as characteristics of living organisms, abiogenesis, evolution of cells, photosynthesis, eukaryotic origins, multicellularity, the Cambrian explosion, common ancestry, and biological diversity.
Lecture_1_Characteristics+of+life.pdf
Card 1
Q: What characteristics are shared by all living organisms?
A:
Living organisms:
Are made of cells
Are composed of a common set of molecules
Carry out metabolism
Contain genetic information
Use a universal molecular/genetic code
Regulate their internal environment
Reproduce
Exist in populations that evolve
Understanding:
These characteristics aren’t simply a checklist. Together, they reflect the underlying organization of life: information + energy processing + compartmentalization + reproduction + regulation + evolution.
Card 2
Q: Why is the cell considered a fundamental unit of life?
A:
Because living systems are cellular. Cells provide the physical organization necessary for:
Metabolism
Regulation
Genetic information
Reproduction
Even multicellular organisms ultimately depend on individual cells performing specialized functions.
Card 3
Q: What is metabolism, and why is it a characteristic of life?
A:
Metabolism is the set of chemical processes through which organisms acquire, transform, and use matter and energy.
Why it matters: Cells need energy and molecular building blocks to maintain organization, grow, reproduce, and regulate themselves.
Card 4
Q: What is abiogenesis?
A:
Abiogenesis refers to the origin of life from nonliving matter through chemical evolution.
The lecture discusses the Miller-Urey experiment as an example of experiments investigating whether biologically relevant molecules could form under early-Earth-like conditions.
Lecture_1_Characteristics+of+life.pdf
Card 5
Q: What did the Miller-Urey experiment demonstrate, and what did it NOT demonstrate?
A:
It demonstrated that certain organic molecules, including amino acids, could form under experimentally simulated conditions.
It did not demonstrate that a complete living organism spontaneously formed.
Exam reasoning:
Formation of biological building blocks ≠ formation of life itself.
Card 6
Q: How did photosynthesis influence the history of life?
A:
Photosynthesis increased the availability of O₂ in Earth’s environment.
This enabled the evolution/expansion of aerobic metabolism, which produces much more ATP than anaerobic metabolism.
Lecture_1_Characteristics+of+life.pdf
Card 7
Q: Why was increased atmospheric oxygen evolutionarily important?
A:
Oxygen could serve as an electron acceptor in aerobic metabolism.
Because aerobic metabolism yields more ATP, organisms could potentially support:
Greater activity
Larger bodies
More energetically expensive biological processes
This contributed to later ecological diversification.
Card 8
Q: What is endosymbiosis?
A:
Endosymbiosis is the evolutionary process in which one organism/cell lives within another and the relationship becomes integrated into the biology of the host.
Your lecture connects this concept to the evolution of eukaryotic cells.
Lecture_1_Characteristics+of+life.pdf
Card 9
Q: How did multicellularity evolve?
A:
The lecture emphasizes cellular specialization within cell colonies.
Instead of every cell performing every function, cells can become specialized for different functions.
Card 10
Q: Why does cellular differentiation occur in multicellular organisms?
A:
Cells can have the same genome but express different sets of genes.
Different gene-expression patterns cause cells to develop different structures and functions.
Lecture_1_Characteristics+of+life.pdf
Key distinction:
Same genome ≠ same cell function.
Card 11
Q: What factors contributed to the Cambrian explosion?
A:
Your lecture identifies several:
Higher O₂ levels
More efficient aerobic respiration
Ability to support larger/more active organisms
Expansion into new ecological niches
Evolution of predation
Protective structures/behaviors
Hox gene duplication and increased developmental complexity
Lecture_1_Characteristics+of+life.pdf
Card 12
Q: What evidence supports the idea that all life shares a common origin?
A:
Living organisms share:
Cells
Metabolism
Genetic information
A genetic code
Reproduction
Populations capable of evolution
Internal regulation
The universal genetic code is especially powerful evidence of shared biological ancestry.
Lecture_1_Characteristics+of+life.pdf
Card 13
Q: What is the relationship between genes, genomes, and genetics?
A:
Gene: a unit of genetic information.
Genome: the complete genetic information of an organism.
Genetics: the study of heredity and genetic information.
Think hierarchy:
Gene → part of genome → studied through genetics.
Card 14
Q: How does natural selection produce evolutionary change?
A:
Natural selection changes the genetic composition of populations over generations because individuals with heritable traits that improve reproductive success tend to contribute more offspring to future generations.
Important:
Natural selection acts on individual phenotypes, but evolutionary change occurs in populations.
Card 15
Q: What mechanisms can produce evolutionary change?
A:
Your lecture lists:
Natural selection
Sexual selection
Genetic drift
Gene flow
Mutation
Lecture_1_Characteristics+of+life.pdf
PART II — SCIENTIFIC METHOD
Learning Objective 1.3
Card 16
Q: What is the basic logic of the scientific method?
A:
A simplified sequence:
Observation → question → hypothesis → prediction → experiment → data → statistical analysis → conclusion → replication
The important idea is that scientific investigation is iterative, not simply a straight line.
Card 17
Q: What is inductive reasoning?
A:
Reasoning from specific observations → general conclusion.
Example:
You observe several populations in which a particular environmental condition is associated with a trait → you develop a general hypothesis about the relationship.
Card 18
Q: What is deductive reasoning?
A:
Reasoning from a general principle/hypothesis → specific prediction.
Example:
Hypothesis: Temperature affects enzyme activity.
Prediction: If temperature changes, enzyme activity will change in a measurable way.
Card 19
Q: What makes a hypothesis scientifically useful?
A:
It must generate testable predictions.
A hypothesis that cannot potentially be supported or contradicted by observations isn’t experimentally useful.
Card 20
Q: What is a null hypothesis?
A:
The null hypothesis generally states that there is no effect, difference, or relationship.
Example:
Research question: Does fertilizer increase plant growth?
H₀: Fertilizer has no effect on plant growth.
Card 21
Q: Why do scientists use null hypotheses?
A:
Statistical testing evaluates whether the observed data are sufficiently inconsistent with the null hypothesis to justify rejecting it.
Important:
Failing to reject H₀ does not prove H₀ is true.
Card 22
Q: What is a controlled experiment?
A:
An experiment designed so that variables other than the factor being tested are controlled as much as possible.
Goal: isolate the effect of the independent variable.
Card 23
Q: What is a comparative experiment?
A:
An experiment comparing different conditions/groups to determine whether a variable is associated with differences in an outcome.
Card 24
Q: Why are uncontrolled variables a problem?
A:
They create alternative explanations for the observed results.
If temperature, nutrient availability, and light all change simultaneously, you cannot confidently conclude which variable caused the effect.
Card 25
Q: Why can experiments involving animals be relevant to human biology?
A:
Different organisms share evolutionary ancestry and therefore share biological mechanisms.
However, similarity does not mean that results from another species automatically apply identically to humans.
PART III — ATOMS & ELEMENTS
Your Lecture 2 begins with atoms as structural units of matter and specifically emphasizes subatomic particles, elements, atomic number/weight, isotopes, and electron position.
Lecture_2_Chemistry+of+life.pdf
Card 26
Q: What are the three major subatomic particles?
A:
Particle | Charge | Approx. mass | Location |
Proton | +1 | 1 Da | Nucleus |
Neutron | 0 | 1 Da | Nucleus |
Electron | −1 | ~0 Da | Orbitals |
The nucleus contains almost all of an atom’s mass while occupying a tiny fraction of its volume.
Lecture_2_Chemistry+of+life.pdf
Card 27
Q: What determines an element’s identity?
A:
The number of protons.
This is the atomic number.
For example:
Carbon = 6 protons
Oxygen = 8 protons
Hydrogen = 1 proton
Changing the number of protons changes the element.
Card 28
Q: What is the atomic number?
A:
The number of protons in the nucleus.
Card 29
Q: What is the mass number?
A:
Mass number = protons + neutrons
Electrons contribute negligibly to the mass number.
Card 30
Q: An atom has 17 protons and 18 neutrons. What are its atomic number and mass number?
A:
Atomic number = 17
Mass number = 17 + 18 = 35
Therefore, this is chlorine-35.
Card 31
Q: What is an isotope?
A:
An isotope is a form of an element with a different number of neutrons.
Because the number of protons stays the same, isotopes remain the same element.
Card 32
Q: Compare oxygen-16 and oxygen-18.
A:
Oxygen always has 8 protons.
Oxygen-16:
8 protons
8 neutrons
8 electrons if neutral
Oxygen-18:
8 protons
10 neutrons
8 electrons if neutral
The difference is two additional neutrons.
Card 33
Q: What is a radioisotope?
A:
An unstable isotope that releases energy through radioactive decay.
Radioisotopes can be used in areas such as:
Fossil dating
Medical imaging, including PET scans
Lecture_2_Chemistry+of+life.pdf
Card 34
Q: Why can radioactive decay sometimes create a different element?
A:
Some radioactive decay processes change the number of protons.
Because proton number determines elemental identity, changing proton number creates a different element.
PART IV — PERIODIC TABLE & ELECTRONS
Card 35
Q: What determines where an element appears on the periodic table?
A:
Elements are arranged by increasing atomic number.
Card 36
Q: Why do elements in the same column often have similar chemical properties?
A:
They have similar valence-electron configurations, particularly similar numbers of electrons in their outermost shell.
Your lecture specifically states that atoms in the same column have the same number of electrons in the outer shell and similar chemical properties.
Lecture_2_Chemistry+of+life.pdf
Card 37
Q: What is the valence shell?
A:
The atom’s outermost occupied electron shell.
Its electrons are especially important because they participate in chemical bonding.
Card 38
Q: Why are valence electrons more important for chemistry than inner electrons?
A:
Valence electrons are the electrons most available to interact with other atoms.
Therefore, their arrangement influences:
Bonding
Reactivity
Molecular structure
Chemical properties
Card 39
Q: How does valence-shell configuration influence placement on the periodic table?
A:
Elements within the same group have related valence-electron configurations.
Therefore, their chemical behavior tends to be similar.
Exam connection:
Periodic-table position → valence electrons → bonding behavior → chemical properties.
Card 40
Q: What is the octet rule?
A:
Atoms tend to gain, lose, or share electrons to achieve a stable outer shell containing eight valence electrons.
Your lecture presents this as a tendency rather than an absolute law.
Lecture_2_Chemistry+of+life.pdf
Card 41
Q: Why does bonding help a reactive atom achieve stability?
A:
Atoms with incomplete valence shells can lower their energetic instability by:
Gaining electrons
Losing electrons
Sharing electrons
These processes can produce a more stable valence-shell configuration.
Card 42
Q: Why are atoms with unfilled/unpaired outer orbitals generally more reactive?
A:
Their valence-electron configuration is less stable, making them more likely to participate in interactions that change their electron arrangement.
PART V — COVALENT BONDING
Card 43
Q: What is a covalent bond?
A:
A chemical bond formed when atoms share one or more pairs of electrons.
Covalent bonds are strong and require substantial energy to break.
Lecture_2_Chemistry+of+life.pdf
Card 44
Q: Why are covalent bonds so strong?
A:
The shared electrons are attracted to the positively charged nuclei of both bonded atoms.
This shared-electron arrangement creates a strong attractive interaction holding the atoms together.
Card 45
Q: What is a single covalent bond?
A:
Two atoms share one electron pair = 2 electrons.
Example:
H—H
Card 46
Q: What is a double covalent bond?
A:
Two atoms share two electron pairs = 4 electrons.
Example:
O=O
Card 47
Q: What is a triple covalent bond?
A:
Two atoms share three electron pairs = 6 electrons.
Example:
N≡N
Card 48
Q: Rank single, double, and triple covalent bonds by strength.
A:
Single < Double < Triple
Your lecture explicitly gives this relationship.
Lecture_2_Chemistry+of+life.pdf
Card 49
Q: Why does covalent-bond geometry matter biologically?
A:
The orientation of covalent bonds determines a molecule’s three-dimensional shape.
Molecular shape influences biological function.
Therefore:
Electron arrangement → bond geometry → molecular shape → biological function.
PART VI — ELECTRONEGATIVITY & POLARITY
Card 50
Q: What is electronegativity?
A:
The attractive force an atomic nucleus exerts on electrons.
It depends partly on:
Nuclear positive charge
Distance between the nucleus and valence electrons
Lecture_2_Chemistry+of+life.pdf
Card 51
Q: What is a nonpolar covalent bond?
A:
A covalent bond in which electrons are shared approximately equally because the atoms have similar electronegativities.
Card 52
Q: What is a polar covalent bond?
A:
A covalent bond in which electrons are shared unequally because the atoms have different electronegativities.
The more electronegative atom attracts the shared electrons more strongly.
Lecture_2_Chemistry+of+life.pdf
Card 53
Q: Does a polar covalent bond mean the atoms have full charges?
A:
No.
They have partial charges, represented as:
δ+ and δ−
The electrons are shared, but unequally.
Card 54
Q: Why is O–H polar?
A:
Oxygen is more electronegative than hydrogen.
Therefore, the shared electrons spend more time near oxygen.
Result:
Oδ− — Hδ+
PART VII — IONIC ATTRACTIONS
Card 55
Q: How does an ionic interaction form?
A:
An electron is transferred from one atom to another, producing oppositely charged ions that attract each other.
Your lecture describes this as occurring when a weakly electronegative atom transfers an electron to a strongly electronegative atom.
Lecture_2_Chemistry+of+life.pdf
Card 56
Q: What is a cation?
A:
A positively charged ion.
It has lost electrons.
Card 57
Q: What is an anion?
A:
A negatively charged ion.
It has gained electrons.
Card 58
Q: What happens when calcium reacts with chlorine?
A:
Calcium loses two electrons:
Ca → Ca²⁺ + 2e⁻
Each chlorine gains one:
Cl + e⁻ → Cl⁻
Therefore:
Ca²⁺ + 2Cl⁻ → CaCl₂
PART VIII — HYDROGEN BONDS & WEAK INTERACTIONS
Card 59
Q: What is a hydrogen bond?
A:
An attraction between a hydrogen atom involved in a polar covalent bond and a strongly electronegative atom.
It results from partial charges, not complete electron transfer.
Lecture_2_Chemistry+of+life.pdf
Card 60
Q: Why is an individual hydrogen bond weak compared with a covalent bond?
A:
Hydrogen bonds result from partial charges rather than direct electron sharing.
However, many hydrogen bonds together can have major biological effects.
Card 61
Q: Why are hydrogen bonds biologically important despite being individually weak?
A:
Large numbers of hydrogen bonds can collectively stabilize biological structures.
For example, hydrogen bonding contributes to the folding and structure of macromolecules.
Card 62
Q: What are hydrophilic interactions?
A:
Interactions involving substances that interact favorably with water.
Polar and charged substances tend to be hydrophilic because they can interact with water’s partial charges.
Card 63
Q: What are hydrophobic interactions?
A:
The tendency of nonpolar molecules/groups to aggregate together rather than interact favorably with water.
Your lecture specifically describes hydrophobic interactions as aggregation of nonpolar molecules.
Lecture_2_Chemistry+of+life.pdf
Card 64
Q: Why do nonpolar molecules tend to aggregate in water?
A:
Nonpolar molecules cannot form favorable interactions with water like polar/charged molecules can.
Their aggregation reduces the amount of nonpolar surface exposed to water.
Important:
“Hydrophobic” does not mean the molecules literally repel water like magnets repel each other.
Card 65
Q: What are van der Waals forces?
A:
Weak, temporary attractions caused by fluctuations in electron distribution that create temporary partial charges in nearby atoms/molecules.
They occur when atoms are very close together.
Lecture_2_Chemistry+of+life.pdf
Card 66
Q: Why can van der Waals forces matter if each interaction is weak?
A:
Many weak interactions occurring simultaneously can collectively contribute significantly to molecular structure and stability.
PART IX — CHEMICAL REACTIONS & THERMODYNAMICS
Card 67
Q: What constitutes a chemical reaction?
A:
Atoms collide with sufficient energy to combine or change their bonding partners.
Lecture_2_Chemistry+of+life.pdf
Card 68
Q: What happens to atoms during a chemical reaction?
A:
Atoms are rearranged.
Chemical reactions do not create or destroy matter.
Card 69
Q: State the law of conservation of energy.
A:
Energy cannot be created or destroyed.
It can be transferred or transformed.
Card 70
Q: State the law of conservation of matter.
A:
Matter cannot be created or destroyed in a chemical reaction.
Atoms are rearranged into new combinations.
Lecture_2_Chemistry+of+life.pdf
PART X — WATER
The Lecture 2 learning outcomes specifically include water’s tetrahedral structure, polarity, specific heat, heat of vaporization, cohesion/adhesion, solvent properties, moles, molarity, pH, weak acid/base behavior, and buffers.
Lecture_2_Chemistry+of+life.pdf
Card 71
Q: Why is water a polar molecule?
A:
Water contains polar O–H covalent bonds because oxygen attracts electrons more strongly than hydrogen.
Additionally, water has a bent/tetrahedral electron geometry, so the bond dipoles do not cancel.
Therefore water has an overall dipole.
Card 72
Q: Why does water’s shape matter?
A:
Molecular geometry determines whether individual bond polarities cancel.
Because water’s geometry produces an overall dipole, water molecules can form strong interactions with one another and with other polar/charged substances.
Card 73
Q: How many hydrogen bonds can one water molecule potentially participate in?
A:
Up to four:
Two through its hydrogen atoms as hydrogen-bond donors
Two through oxygen’s lone pairs as hydrogen-bond acceptors
In liquid water, the bonds are constantly breaking and reforming.
Your lecture emphasizes that water is highly dynamic and that a water molecule averages about 3.4 hydrogen bonds with other water molecules.
Lecture_2_Chemistry+of+life.pdf
PART XI — WATER & TEMPERATURE
Card 74
Q: What is specific heat?
A:
The amount of heat energy required to raise the temperature of 1 gram of a substance by 1°C.
Card 75
Q: Why does water have a high specific heat?
A:
Much of the added energy can be absorbed by disrupting/rearranging hydrogen-bond interactions rather than immediately increasing molecular motion.
Therefore, water’s temperature changes relatively slowly.
Card 76
Q: What is the biological importance of water’s high specific heat?
A:
It helps stabilize temperatures in:
Aquatic environments
Organisms
Earth’s climate
The lecture specifically connects water’s high specific heat to relatively stable aquatic environments and reduced atmospheric temperature variation.
Lecture_2_Chemistry+of+life.pdf
Card 77
Q: Why does water require a lot of energy to evaporate?
A:
Hydrogen bonds between water molecules must be disrupted sufficiently for molecules to escape the liquid and enter the gas phase.
Card 78
Q: What is heat of vaporization?
A:
The amount of heat required to convert a substance from liquid to gas.
Water has a high heat of vaporization.
Lecture_2_Chemistry+of+life.pdf
Card 79
Q: Why does sweating cool the body?
A:
Evaporation requires substantial energy.
When water evaporates from the skin, it removes heat from the body.
Chain:
Hydrogen bonding → high heat of vaporization → evaporation removes heat → cooling.
Card 80
Q: Why does ice float on liquid water?
A:
When water freezes, hydrogen bonds organize molecules into a more open structure.
This increases the volume occupied by the same amount of water, decreasing its density.
Therefore:
Ice is less dense than liquid water → ice floats.
Card 81
Q: Why does ice floating matter biologically?
A:
Floating ice forms an insulating surface layer rather than causing an entire body of water to freeze solid from the bottom upward.
This helps aquatic environments remain habitable during cold conditions.
PART XII — COHESION & ADHESION
Card 82
Q: What is cohesion?
A:
Attraction between molecules of the same substance.
For water, hydrogen bonding creates strong cohesion between water molecules.
Card 83
Q: What is adhesion?
A:
Attraction between different substances.
Water can adhere to other polar surfaces.
Card 84
Q: What is surface tension?
A:
A consequence of strong cohesive forces at a liquid’s surface.
Water molecules at the surface experience strong attraction to neighboring water molecules.
Card 85
Q: Explain how hydrogen bonding produces cohesion.
A:
Water molecule A has partial charges.
Water molecule B has partial charges.
The δ+ hydrogen of one molecule is attracted to the δ− oxygen of another.
Repeated across many molecules:
Hydrogen bonding → cohesion → surface tension
PART XIII — WATER AS A SOLVENT
Card 86
Q: What does it mean to say water is a solvent?
A:
Water can dissolve many substances, making it an important medium for chemical reactions.
Card 87
Q: Why can water dissolve ionic compounds?
A:
Water’s partial charges interact with ions.
For example:
Oxygen’s δ− region interacts with cations.
Hydrogen’s δ+ regions interact with anions.
This can separate ions from an ionic lattice and stabilize them in solution.
Card 88
Q: Why are polar molecules generally more soluble in water than nonpolar molecules?
A:
Polar molecules can form favorable interactions with water.
Nonpolar molecules cannot form comparable favorable interactions with water.
General principle:
“Like interacts favorably with like.”
Card 89
Q: Why are water’s solvent properties important inside cells?
A:
Cells are aqueous environments.
Many cellular processes require molecules to:
Dissolve
Move
Collide
React
Interact with one another
Therefore, water’s solvent properties help make cellular chemistry possible.
PART XIV — MOLES & MOLARITY
This is one of the areas your lecture specifically expects you to perform quantitatively, rather than simply define terms.
Lecture_2_Chemistry+of+life.pdf
Card 90
Q: What is a mole?
A:
A mole is an amount of substance containing approximately:
6.02 × 10²³ particles
This number is Avogadro’s number.
Card 91
Q: What is Avogadro’s number?
A:
6.02 × 10²³ particles/mol
It allows us to connect the microscopic world of molecules with measurable amounts of substance.
Card 92
Q: What is molar mass?
A:
The mass of one mole of a substance, expressed in g/mol.
For a compound, calculate it by adding the atomic masses of all atoms in its molecular formula.
Card 93
Q: What is the molar mass of H₂O?
A:
2 H + 1 O
≈ 2(1.008) + 16.00
≈ 18.02 g/mol
Therefore:
1 mol H₂O ≈ 18.02 g
Card 94
Q: How do you convert grams to moles?
A:
\text{moles}=\frac{\text{mass in grams}}{\text{molar mass in g/mol}}
Card 95
Q: How do you convert moles to grams?
A:
\text{grams}=\text{moles}\times\text{molar mass}
Card 96
Q: What is molarity?
A:
M=\frac{\text{moles of solute}}{\text{liters of solution}}
Molarity tells you how many moles of solute are present per liter of solution.
Card 97
Q: Why must volume be in liters when calculating molarity?
A:
Because molarity is defined as moles per liter.
Therefore:
500 mL = 0.500 L
Card 98
Q: A solution contains 0.20 mol glucose in 2.0 L. What is its molarity?
A:
M=\frac{0.20}{2.0}
M = 0.10 M
Card 99
Q: A student dissolves 5.85 g NaCl in 500 mL solution. What is the molarity?
A:
Molar mass NaCl:
22.99 + 35.45 = 58.44 g/mol
Convert mass:
5.85 g ÷ 58.44 g/mol = 0.100 mol
Convert volume:
500 mL = 0.500 L
Then:
M=\frac{0.100}{0.500}
M = 0.200 M
This is the quantitative example provided in your lecture.
Lecture_2_Chemistry+of+life.pdf
Card 100
Q: What does 10 mM mean?
A:
mM = millimolar
10\text{ mM}=0.010\text{ M}=10^{-2}\text{ M}
Card 101
Q: How many molecules are present per liter in a 10 mM solution?
A:
10 mM = 0.010 M
0.010 \times 6.02\times10^{23}
=
6.02 × 10²¹ molecules/L
This exact conversion appears in your lecture.
Lecture_2_Chemistry+of+life.pdf
PART XV — ACIDS & BASES
Card 102
Q: What is an acid according to your course’s definition?
A:
A substance that releases H⁺ in solution.
Card 103
Q: What is a base?
A:
A substance that accepts H⁺ in solution.
Card 104
Q: What is a strong acid?
A:
An acid that dissociates essentially completely in solution.
Example:
HCl → H⁺ + Cl⁻
Card 105
Q: What is a weak acid?
A:
An acid in which only a fraction of molecules dissociate.
Example:
CH₃COOH ⇌ CH₃COO⁻ + H⁺
Your lecture emphasizes that weak-acid ionization is reversible.
Lecture_2_Chemistry+of+life.pdf
Card 106
Q: Why is acetic acid considered weak?
A:
Because only a fraction of its molecules dissociate into ions.
Your lecture gives an example in which approximately 4 out of 100 molecules dissociate.
Lecture_2_Chemistry+of+life.pdf
Card 107
Q: What is the difference between acid strength and acid concentration?
A:
Strength describes the tendency of an acid to dissociate.
Concentration describes how much acid is present.
A weak acid can be highly concentrated, and a strong acid can be very dilute.
Card 108
Q: Why is this distinction important?
A:
Because changing concentration does not necessarily change the intrinsic strength of an acid.
It changes how many acid molecules are present per volume.
PART XVI — WATER AS BOTH ACID AND BASE
Card 109
Q: Why can water act as both an acid and a base?
A:
Water can:
Donate H⁺ → act as an acid
Accept H⁺ → act as a base
Your lecture emphasizes that water has a slight tendency to ionize and therefore behaves as both.
Lecture_2_Chemistry+of+life.pdf
Card 110
Q: Why is water’s ionization biologically important?
A:
Water is abundant in living systems, and H⁺ ions are highly chemically reactive.
Therefore, even relatively small changes in H⁺ concentration can influence biological molecules and reactions.
PART XVII — pH
Card 111
Q: What is pH?
A:
\boxed{pH=-\log[H^+]}
where [H⁺] is the molar concentration of hydrogen ions.
This definition appears directly in your lecture.
Lecture_2_Chemistry+of+life.pdf
Card 112
Q: What happens to pH when H⁺ concentration increases?
A:
pH decreases.
More H⁺ = more acidic = lower pH.
Card 113
Q: What happens to pH when H⁺ concentration decreases?
A:
pH increases.
Less H⁺ = less acidic/more basic = higher pH.
Card 114
Q: If [H⁺] = 1 × 10⁻³ M, what is pH?
A:
pH=-\log(10^{-3})
\boxed{pH=3}
Card 115
Q: If [H⁺] changes from 10⁻⁶ M to 10⁻⁴ M, what happens to pH?
A:
Initial:
pH = 6
Final:
pH = 4
Therefore pH decreases by 2 units.
The H⁺ concentration increased by:
\frac{10^{-4}}{10^{-6}}=100
So a 100-fold increase in H⁺ produced a 2-unit decrease in pH.
PART XVIII — WEAK ACIDS, BASES & pH PREDICTIONS
Card 116
Q: If the concentration of a weak acid increases, what would you generally predict happens to pH?
A:
More weak acid molecules are available to dissociate and contribute H⁺.
Therefore, you generally predict:
[weak acid] ↑ → [H⁺] ↑ → pH ↓
The exact magnitude depends on the acid’s equilibrium behavior.
Card 117
Q: If the concentration of a weak acid decreases, what would you generally predict happens to pH?
A:
[weak acid] ↓ → [H⁺] tends to ↓ → pH tends to ↑
Again, the exact change depends on the equilibrium.
Card 118
Q: Why can’t you simply assume that doubling a weak acid’s concentration doubles [H⁺]?
A:
Because weak acids establish an equilibrium between dissociated and undissociated forms.
Changing concentration can shift that equilibrium, so [H⁺] does not necessarily scale linearly with the amount of acid added.
This is exactly the kind of prediction/application question you should expect at the college level.
Card 119
Q: What happens when a weak acid dissociates?
A:
HA \rightleftharpoons H^+ + A^-
Increasing HA provides more reactant, potentially shifting the equilibrium toward the products.
PART XIX — BUFFERS & HOMEOSTASIS
Card 120
Q: What is a buffer?
A:
A buffer consists of a weak acid and its corresponding base.
Example:
H_2CO_3 \rightleftharpoons HCO_3^- + H^+
Your lecture identifies buffers as an important mechanism for maintaining homeostasis.
Lecture_2_Chemistry+of+life.pdf
Card 121
Q: How does a buffer resist changes in pH when acid is added?
A:
The corresponding base can react with the added H⁺.
For example:
HCO_3^- + H^+ \rightarrow H_2CO_3
Thus, some of the added H⁺ is consumed rather than remaining free in solution.
Card 122
Q: How does a buffer respond when base is added?
A:
The weak acid can donate H⁺ to react with the added base.
This reduces the change in free H⁺ concentration.
Card 123
Q: What is the law of mass action in the context of buffers?
A:
In a reversible reaction, adding more reactant tends to shift the system toward the direction that consumes that reactant.
Your lecture applies this principle directly to buffer systems.
Lecture_2_Chemistry+of+life.pdf
Card 124
Q: Why are buffers important for living organisms?
A:
pH affects biological reactions and can alter the 3-D structure and function of biological molecules.
Therefore, maintaining relatively stable pH is necessary for biological homeostasis.
Lecture_2_Chemistry+of+life.pdf
PART XX — HIGHER-LEVEL “PROFESSOR COULD ASK THIS” CARDS
These are especially important because they force you to connect concepts instead of memorizing them.
Card 125
Q: Predict what happens to an aqueous environment if many nonpolar molecules are introduced. Explain why.
A:
The nonpolar molecules tend to aggregate through hydrophobic interactions.
Why?
They do not interact favorably with water, so clustering reduces their exposure to the aqueous environment.
Card 126
Q: A mutation changes a protein’s amino acid sequence. Why could this change the protein’s function even if only one amino acid changes?
A:
An amino-acid substitution can change:
Polarity
Charge
Hydrogen-bonding interactions
Hydrophobic interactions
Van der Waals interactions
These changes can alter the protein’s 3-D structure, which can alter its function.
Card 127
Q: Connect electronegativity to water’s biological importance.
A:
Different electronegativities → unequal electron sharing in O–H bonds → partial charges → water polarity → hydrogen bonding → cohesion, high specific heat, high heat of vaporization, and solvent properties.
This is a major conceptual chain to know.
Card 128
Q: Why does water have both a high specific heat and a high heat of vaporization?
A:
Both properties arise largely from water’s extensive hydrogen-bond network.
Specific heat: Energy is required to disrupt/rearrange hydrogen bonds before temperature rises substantially.
Vaporization: Significant energy is required to separate molecules sufficiently to enter the gas phase.
Card 129
Q: Why does molecular geometry matter when determining whether a molecule is polar?
A:
Individual bonds can be polar, but the overall molecule may or may not have a net dipole depending on how those bond dipoles are arranged in space.
Therefore:
Bond polarity + molecular geometry → molecular polarity
Card 130
Q: Why can an atom have the same number of protons but a different mass?
A:
Because isotopes have the same number of protons but different numbers of neutrons.
Card 131
Q: An atom loses an electron. Does it become a different element?
A:
No.
The element is determined by the number of protons.
Losing an electron changes the atom’s charge, producing an ion, but it does not change its elemental identity.
Card 132
Q: An atom gains a proton. Does it become a different element?
A:
Yes.
Changing proton number changes the atomic number, which changes the element.
Card 133
Q: Why is carbon particularly important in biological molecules?
A:
The materials you’ve provided establish that C, H, O, N, P, and S are major elements in living tissue and show carbon-containing molecules such as glucose, glycerol, and tryptophan.
Lecture_2_Chemistry+of+life.pdf
The lecture materials provided here do not give a detailed explanation of carbon’s bonding versatility, so I would not treat that explanation as lecture-derived yet.
Card 134
Q: Earth’s crust and the human body are both matter. Should you expect them to have the same elemental composition? Why?
A:
No.
Different environments and biological systems have different chemical requirements and histories.
Your lecture establishes that living tissues contain a characteristic set of elements, particularly C, O, H, N, P, and S, along with biologically important ions such as Na⁺, K⁺, Ca²⁺, Fe²⁺/Fe³⁺, Mg²⁺, Cu²⁺, and Mn²⁺.
Lecture_2_Chemistry+of+life.pdf
🔥 THE 10 CONCEPTUAL CHAINS I WOULD MEMORIZE
Don’t memorize these as isolated facts. Be able to explain every arrow.
1. Periodic table
Atomic number → electron configuration → valence electrons → bonding → chemical properties
2. Stability
Incomplete valence shell → reactivity → gain/lose/share electrons → more stable configuration
3. Polar covalent bonding
Different electronegativities → unequal electron sharing → partial charges → polarity
4. Water
O–H polarity + bent geometry → water polarity → hydrogen bonding
5. Water temperature regulation
Hydrogen bonding → high specific heat → resistance to temperature change
6. Evaporative cooling
Hydrogen bonding → high heat of vaporization → energy required for evaporation → heat removed from surface
7. Water cohesion
Water polarity → hydrogen bonding → cohesion → surface tension
8. Water as solvent
Water polarity → interactions with ions/polar molecules → dissolution → aqueous cellular reactions
9. pH
[H⁺] ↑ → pH ↓
[H⁺] ↓ → pH ↑
Remember that because of the logarithmic scale, the relationship isn’t linear.
10. Buffer/homeostasis
Added H⁺ → corresponding base consumes H⁺
Added base → weak acid supplies H⁺
→ smaller pH change
🧠 WHAT YOUR PROFESSOR IS REALLY TESTING
Based on the objectives and your lecture, I would divide your studying into three levels:
Level 1 — Know it
You should instantly know:
Atomic number
Mass number
Isotope
Valence electron
Octet rule
Covalent bond
Ionic interaction
Hydrogen bond
Hydrophobic/hydrophilic
Van der Waals
Mole
Molarity
Acid/base
pH
Buffer
Level 2 — Explain it
You should be able to answer:
“Why?”
For example:
Why does water have a high specific heat?
Don’t answer merely “because of hydrogen bonds.”
Answer the mechanism:
Hydrogen bonding creates interactions between water molecules that require energy to disrupt/rearrange, so substantial energy can be absorbed without producing an equivalent increase in temperature.
Level 3 — Predict it
This is where I’d expect the harder BIOSC 0150 questions.
For example:
A cell experiences an increase in H⁺ concentration. Predict what happens to pH and explain why.
You should immediately reason:
[H^+] \uparrow
therefore
pH=-\log[H^+]
so
\boxed{pH\downarrow}
And then connect that to biology:
pH change → altered molecular interactions → potentially altered 3-D structure/function → biological consequences.
Your lecture explicitly emphasizes that pH can affect biological reaction rates and the 3-D structure/function of biological molecules.
Lecture_2_Chemistry+of+life.pdf
⭐ Most important for your upcoming studying
I would not make one giant stack and simply reread it.
Use these in this order:
Day 1: Cards 26–58 — atoms + bonding
Day 2: Cards 59–89 — interactions + water
Day 3: Cards 90–101 — moles/molarity calculations
Day 4: Cards 102–124 — acids, bases, pH, buffers
Day 5: Cards 125–134 — application/conceptual questions
Then: Mix everything together and answer without looking at the answers.
For the mole/molarity and pH sections, don’t just use flashcards. You need to actually work problems, because knowing the formula isn’t the same as being able to perform the analysis. Your lecture specifically includes quantitative analysis of molarity and conversions between grams, moles, liters, and molecules.
Lecture_2_Chemistry+of+life.pdf