Chem Exam 1 Cram

L1 Memory & Learning — Neuron

Specialized nervous-system cell that sends and receives signals.

L1 Memory & Learning — Glial cell

Supporting cell of the nervous system.

L1 Memory & Learning — Synapse

Junction where neurons communicate, often using chemical neurotransmitters.

L1 Memory & Learning — Neuronal plasticity

Ability of the nervous system to be modified after birth, often through changes at synapses.

L1 Memory & Learning — How does repeated activity change synapses?

Used connections can become stronger or more numerous; unused connections weaken and may be removed.

L1 Memory & Learning — What is memory in this course?

An anatomical/physiological event at synapses that depends on neuronal plasticity and activity.

L1 Memory & Learning — Memory vs. learning

Memory stores information; learning uses stored information to change behavior and reduce negative outcomes.

L1 Memory & Learning — Short-term memory: duration and capacity

Seconds to minutes; limited to roughly seven items (about 7 ± 2).

L1 Memory & Learning — Long-term memory: duration and capacity

As far as we can tell, essentially indefinite duration and unlimited capacity.

L1 Memory & Learning — Why must LTM be retrieved?

Information in LTM must be brought back into STM before it can be used.

L1 Memory & Learning — Encoding

Getting stimulus information into short-term memory.

L1 Memory & Learning — Consolidation or repeated encoding

Strengthening/storing information so it moves from short-term into long-term memory.

L1 Memory & Learning — Retrieval

Bringing a stored long-term memory back into short-term memory.

L1 Memory & Learning — Memory formation sequence

Stimulus → encoding → STM → repeated encoding/consolidation → LTM → retrieval → STM → use.

L1 Memory & Learning — Neuronal plasticity vs. long-term potentiation

Plasticity is structural/functional change; LTP is a lasting increase in synaptic transmission strength.

L1 Memory & Learning — What causes long-term potentiation?

Repeated use and retrieval of information strengthens synapses over time.

L1 Memory & Learning — What is the practical benefit of LTP?

Retrieval becomes easier and may no longer require external hints or cues.

L1 Memory & Learning — How do organization and chunking improve memory?

They associate related information, making it easier to encode and retrieve.

L1 Memory & Learning — What does 'use it or lose it' describe?

Activity preserves and strengthens connections; inactivity allows weakening and loss.

L1 Memory & Learning — Component-level vs. systems-level question

Component: recall one fact; systems: connect, sequence, apply, or predict from multiple concepts.

L2 Foundations — Evolution as a unifying theme

Living organisms are modified descendants of common ancestors.

L2 Foundations — Emergent property

A property produced by interactions among components that individual parts lack.

L2 Foundations — Steps in the scientific method

Observation/question → background information → hypothesis → prediction → data collection → evaluation → repeat/revise.

L2 Foundations — Hypothesis

Testable proposed explanation for observations.

L2 Foundations — Prediction

Expected observable result if the hypothesis is correct.

L2 Foundations — Theory vs. law

A theory broadly explains why; a law describes what consistently occurs under stated conditions.

L2 Foundations — What if evidence fails to support a prediction?

Reevaluate the hypothesis, prediction and procedure; revise and collect more data.

L2 Foundations — Science can study what?

Natural processes that can be observed or measured and tested systematically.

L2 Foundations — Atomic components and charges

Proton positive; neutron neutral; electron negative.

L2 Foundations — Valence shell vs. valence electrons

Valence shell is outermost shell; valence electrons occupy that shell and help form bonds.

L2 Foundations — What happens when an electron moves outward?

It absorbs energy and reaches a higher-energy shell with more potential energy.

L2 Foundations — What happens when an excited electron falls back?

It releases energy, potentially as light or heat.

L2 Foundations — Typical bonds for H, C, N, and O

H forms 1, C forms 4, N forms 3, and O forms 2 covalent bonds in these examples.

L2 Foundations — Electronegativity

An atom's tendency to attract shared electrons.

L2 Foundations — Covalent bond

Two atoms share a pair of electrons; strong under biological conditions.

L2 Foundations — Polar vs. nonpolar covalent

Polar: electrons shared unequally, causing partial charges; nonpolar: nearly equal sharing.

L2 Foundations — Ionic bonding

An electron is transferred; resulting oppositely charged ions attract.

L2 Foundations — Cation vs. anion

Cation loses electrons and is positive; anion gains electrons and is negative.

L2 Foundations — Hydrogen bonding

Relatively weak attraction involving partial charges, often H bonded to O or N.

L2 Foundations — Van der Waals interaction

Weak attractions from temporary partial charges caused by electron movement.

L2 Foundations — Typical bond/interactions strength in water

Covalent strongest, ionic next, then hydrogen bonds/van der Waals interactions.

L2 Foundations — Why is water polar?

Oxygen attracts shared electrons more strongly and becomes δ−; both hydrogens are δ+.

L2 Foundations — What creates water's emergent properties?

Extensive hydrogen bonding between water molecules.

L2 Foundations — How many H-bonds can one water molecule form?

Up to four.

L2 Foundations — Cohesion vs. adhesion

Cohesion is water–water attraction; adhesion is water attraction to other polar/charged substances.

L2 Foundations — High specific heat of water

Water absorbs much heat with relatively little temperature change due to hydrogen bonding.

L2 Foundations — Why does ice float?

The frozen hydrogen-bond lattice spaces molecules farther apart, making ice less dense than liquid water.

L2 Foundations — Why is water an effective solvent?

Its partial charges surround and separate many charged and polar particles.

L2 Foundations — Hydrophilic vs. hydrophobic

Hydrophilic is charged/polar and interacts with water; hydrophobic is nonpolar and poorly dissolves.

L2 Foundations — If a surface attracts water but not nonpolar oil, why?

The surface has polar or charged regions that interact with water.

L3 Biological Molecules — Why can carbon form so many structures?

It has four valence electrons and can make four covalent bonds.

L3 Biological Molecules — Hydrocarbon

Molecule consisting only of carbon and hydrogen; typically nonpolar and hydrophobic.

L3 Biological Molecules — Functional group

Atom group attached to a carbon skeleton that changes chemical properties.

L3 Biological Molecules — Identify hydroxyl from its structure

–OH; polar, hydrophilic, and not treated as acidic in living cells.

L3 Biological Molecules — Identify carbonyl from its structure

C=O; polar and hydrophilic; common in sugars.

L3 Biological Molecules — Identify carboxyl from its structure

–COOH (or –COO− after ionization); acidic and hydrophilic.

L3 Biological Molecules — Identify amino from its structure

–NH2 (or –NH3+ after accepting H+); basic and hydrophilic.

L3 Biological Molecules — Identify phosphate from its structure

Phosphate-containing group with multiple O atoms; strongly acidic and hydrophilic; in ATP and phospholipids.

L3 Biological Molecules — Identify methyl from its structure

–CH3; nonpolar, neutral, and hydrophobic.

L3 Biological Molecules — Which functional groups are acidic or basic?

Carboxyl and phosphate donate H+ (acids); amino accepts H+ (base).

L3 Biological Molecules — Which listed functional groups are polar but not ionized in cells?

Hydroxyl and carbonyl.

L3 Biological Molecules — What makes testosterone and estradiol chemically different?

They share a steroid carbon skeleton but have different attached functional groups.

L3 Biological Molecules — Monomer vs. polymer

Monomer is one repeating unit; polymer is a chain of many linked units.

L3 Biological Molecules — Four major classes of biological molecules

Carbohydrates, lipids, proteins, and nucleic acids.

L3 Biological Molecules — Which of the four is not generally a polymer?

Lipids; unlike the other three, they are not repeating monomer chains.

L3 Biological Molecules — Dehydration synthesis: mechanism

Remove H and OH from reactants, form H2O and a covalent bond that joins them.

L3 Biological Molecules — Hydrolysis: mechanism

Add water to break a covalent bond; H and OH end up on the separate products.

L3 Biological Molecules — Dehydration synthesis vs. hydrolysis

Dehydration builds bigger molecules and releases water; hydrolysis breaks them using water.

L3 Biological Molecules — Carbohydrate monomer and polymer

Monosaccharide (e.g. glucose) builds polysaccharides.

L3 Biological Molecules — Carbohydrates: energy vs. structure

Glucose gives immediate energy; starch/glycogen store energy; cellulose/chitin supply structure.

L3 Biological Molecules — Glycosidic linkage

Covalent connection between sugar units.

L3 Biological Molecules — Fats: structure and main function

Glycerol plus fatty acids; primarily long-term energy storage.

L3 Biological Molecules — Phospholipid: components

Glycerol backbone, two hydrophobic fatty-acid tails, and a hydrophilic phosphate head.

L3 Biological Molecules — Steroids: appearance and function

Hydrophobic fused-ring molecules often used for signaling (such as steroid hormones).

L3 Biological Molecules — Which bond links fatty acid to glycerol?

Ester linkage.

L3 Biological Molecules — Protein monomer and linkage

Amino acids joined by peptide bonds to make polypeptides.

L3 Biological Molecules — What broad functions can proteins perform?

Catalysis, structure, transport, signaling, defense, and many others; not heredity itself.

L3 Biological Molecules — Nucleic acids' principal role

Store and transmit genetic information, as in DNA and RNA.

L3 Biological Molecules — Primary protein structure

Sequence of amino acids in one polypeptide.

L3 Biological Molecules — Secondary protein structure

Short-range or local folding within a polypeptide.

L3 Biological Molecules — Tertiary protein structure

Overall 3-D shape formed by longer-range folding of one polypeptide.

L3 Biological Molecules — Quaternary protein structure

Multiple polypeptide chains associate to form one protein.

L3 Biological Molecules — Denaturation

Protein loses its normal three-dimensional shape, impairing function.

L3 Biological Molecules — What happens if a protein loses its tertiary structure?

Its binding or activity may fail even if the amino-acid sequence remains intact.

L3 Biological Molecules — Why are lipids commonly hydrophobic?

Much of their structure consists of nonpolar hydrocarbon regions.

L4 Origin of Life — Abiogenesis

Development of the first cells from nonliving precursors.

L4 Origin of Life — Four requirements for abiotic organic synthesis

Low free O2; inorganic chemical precursors; environmental energy; and extensive time.

L4 Origin of Life — Why did early abiotic synthesis require little free oxygen?

O2 is a reactive oxidizing agent that can interfere with forming organic molecules.

L4 Origin of Life — What chemical elements did early organic synthesis need?

Sources of carbon, hydrogen, oxygen, and nitrogen (CHON).

L4 Origin of Life — Possible energy sources before life

UV sunlight, geothermal or hydrothermal heat, volcanoes, and lightning.

L4 Origin of Life — Oparin–Haldane vs. iron–sulfur hypotheses

Oparin–Haldane: surface or shallow water; iron–sulfur: deep-sea vents.

L4 Origin of Life — Sequence of abiogenesis

Abiotic small organic molecules → organic macromolecules → protocells → self-replication and heredity.

L4 Origin of Life — How may early macromolecules have formed?

Monomers assembled on mineral/clay/rock surfaces, potentially aided by metal ions such as Zn2+ and Fe2+.

L4 Origin of Life — What is a vesicle?

A fluid-filled compartment surrounded by a lipid membrane, potentially forming spontaneously.

L4 Origin of Life — What is a protocell?

An assemblage of abiotic organic molecules in a membrane-bounded compartment with cell-like properties.

L4 Origin of Life — Cell-like features of a protocell

Distinct interior, membrane potential, environmental uptake, and division when sufficiently large.

L4 Origin of Life — Two critical abilities an early protocell lacked

Functional heredity and metabolism.

L4 Origin of Life — RNA–peptide world hypothesis

Early life likely used RNA for genetic information and catalysis, with limited help from peptides.

L4 Origin of Life — Ribozyme

RNA molecule capable of catalyzing reactions; candidate early enzyme/replicator.

L4 Origin of Life — Why is RNA central to the origin-of-life hypothesis?

RNA can both store hereditary information and catalyze biochemical reactions.