bio 140 part 1

What is science?

The objective study of the natural world using evidence, experimentation, and reasoning.

What is the scientific method?

A systematic process to investigate questions, involving observation, hypothesis, experimentation, and analysis.

What are the steps of the scientific method?

1. Observation, 2. Hypothesis, 3. Experiment, 4. Evaluation of results, 5. Accept/reject hypothesis.

Why is the scientific method used?

To minimize bias, ensure repeatability, and test ideas objectively.

What is a hypothesis?

A testable, falsifiable statement that proposes an explanation.

Give an example of a hypothesis.

If fertilizer increases plant growth, then plants with fertilizer will be taller than plants without it.

What is an experimental variable?

The factor being manipulated in an experiment.

What is a dependent variable?

The factor being measured in response to the experimental variable.

What are control variables?

Variables kept constant to ensure fairness and reliability.

Why is sample size important?

Larger samples reduce random error and increase confidence in results.

What role does statistics play in experiments?

They determine whether observed results are significant or due to chance.

What is pseudoscience?

Claims that appear scientific but lack evidence or testability.

Give an example of pseudoscience.

Astrology, which makes unfalsifiable claims about human behavior.

What is the Belmont Report?

A U.S. report establishing ethical guidelines for research involving humans.

What are the three principles of the Belmont Report?

Respect for Persons, Beneficence, and Justice.

What does Respect for Persons mean?

Treating individuals as autonomous agents

What does Beneficence mean?

Do no harm, maximize benefits, minimize risks to participants.

What does Justice mean in research ethics?

Fairness in distribution

What are the seven characteristics of life?

Order, sensitivity to stimuli, reproduction, growth & development, regulation, energy processing, evolutionary adaptation.

Example of order in life.

Cells organized into tissues, tissues into organs.

Example of sensitivity to stimuli.

Plants growing toward light (phototropism).

Example of reproduction.

Bacteria dividing by binary fission.

Example of growth and development.

A caterpillar transforming into a butterfly.

Example of regulation.

Humans sweating to maintain temperature.

Example of energy processing.

Plants performing photosynthesis

Example of evolutionary adaptation.

Camouflage in animals for survival.

What domains exist in life classification?

Bacteria, Archaea, Eukarya.

What are the four kingdoms of Eukarya?

Protista, Fungi, Plantae, Animalia.

What is taxonomy?

The naming and classification of organisms.

What is systematics?

The study of evolutionary relationships among organisms.

What is the hierarchy of biological classification?

Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species.

What is a phylogenetic tree?

A diagram showing evolutionary relationships.

What is binomial nomenclature?

Scientific naming system using Genus and species. Example: Homo sapiens.

What is atomic number?

The number of protons in an atom.

What is atomic mass?

The total number of protons and neutrons.

What are isotopes?

Atoms of the same element with different neutron numbers.

What is ion formation?

When atoms gain or lose electrons to form charged particles.

What are valence electrons?

Outer-shell electrons that determine bonding behavior.

What is a covalent bond?

A bond where atoms share electrons.

What are single, double, and triple covalent bonds?

1, 2, or 3 pairs of shared electrons, respectively.

What is an ionic bond?

Transfer of electrons from one atom to another, creating ions.

What is a hydrogen bond?

Weak attraction between polar molecules.

Why is water polar?

Oxygen pulls electrons more strongly than hydrogen, creating partial charges.

What is cohesion?

Water molecules sticking to each other (surface tension).

What is adhesion?

Water sticking to other surfaces (capillary action).

What is high specific heat of water?

It resists temperature changes, stabilizing environments.

Why is ice less dense than liquid water?

Hydrogen bonding creates open lattice structure in ice.

What is the pH scale?

Measures hydrogen ion concentration: 0–6 acidic, 7 neutral, 8–14 basic.

What makes carbon unique in organic chemistry?

It forms 4 covalent bonds, allowing for diverse molecules.

What are hydrocarbons?

Compounds of only hydrogen and carbon.

Name the functional groups and their properties.

Hydroxyl (–OH, polar), Carbonyl (C=O, polar), Carboxyl (–COOH, acidic), Amino (–NH₂, basic), Sulfhydryl (–SH, disulfide bonds), Phosphate (–PO₄, energy transfer), Methyl (–CH₃, nonpolar).

What are monomers?

Small building blocks of macromolecules.

What are polymers?

Long chains of monomers.

What is dehydration synthesis?

Reaction linking monomers, releasing water.

What is hydrolysis?

Reaction breaking polymers into monomers using water.

What is the general formula for carbohydrates?

(CH₂O)n.

What are monosaccharides?

Simple sugars, e.g., glucose, galactose, fructose.

What are aldoses and ketoses?

Aldose: carbonyl group at end; Ketose: carbonyl group in middle.

What are triose, pentose, hexose sugars?

Monosaccharides with 3, 5, or 6 carbons.

What is the difference between alpha and beta glucose?

Alpha: OH below carbon 1; Beta: OH above carbon 1.

What are disaccharides?

Sugars formed by linking two monosaccharides, e.g., sucrose, lactose, maltose.

What bond joins monosaccharides in disaccharides?

Glycosidic bond.

What are polysaccharides?

Long chains of monosaccharides.

What is starch?

Plant glucose storage

What is glycogen?

Animal glucose storage, highly branched.

What is cellulose?

Plant structural polysaccharide with β 1–4 linkages.

Why can’t humans digest cellulose?

Lack of cellulase enzyme.

What is chitin?

Structural polysaccharide in arthropod exoskeletons and fungal cell walls.

What are lipids?

Hydrophobic macromolecules including fats, oils, waxes, steroids, phospholipids.

What is the structure of fats?

Glycerol backbone + 3 fatty acids (triglyceride).

What is an ester bond?

Bond formed between glycerol and fatty acids.

What are saturated fats?

Fatty acids with no double bonds, solid at room temp.

What are unsaturated fats?

Fatty acids with double bonds, liquid at room temp.

What are cis vs. trans fats?

Cis: hydrogens same side of double bond, kinked; Trans: hydrogens opposite sides, straight.

What are omega-3 fatty acids?

Essential fatty acids with a double bond 3 carbons from the omega end.

What are phospholipids?

Lipids with 2 fatty acids + phosphate group, amphipathic, form bilayers.

What are steroids?

Lipids with 4 fused carbon rings, e.g., cholesterol, testosterone.

What is cholesterol’s role?

Maintains membrane fluidity, precursor for hormones and vitamin D.

What are waxes?

Long fatty acids esterified to alcohols, waterproofing agents.

What are proteins made of?

Amino acids linked by peptide bonds.

What is the structure of an amino acid?

Central carbon with amino group, carboxyl group, hydrogen, and R group.

How many amino acids exist?

20 standard amino acids, 9 essential in humans.

What is a peptide bond?

Covalent bond between amino acids formed during dehydration.

What is primary protein structure?

The sequence of amino acids.

What is secondary structure?

Folding into α-helices and β-sheets via hydrogen bonding.

What is tertiary structure?

3D folding due to R-group interactions (hydrogen bonds, ionic bonds, disulfide bridges, hydrophobic interactions).

What is quaternary structure?

Interaction of multiple polypeptide chains.

What is denaturation?

Protein losing its shape and function due to heat, pH, or chemicals.

What are enzymes?

Proteins that act as biological catalysts.

What are anabolic vs. catabolic enzymes?

Anabolic build molecules; catabolic breaks down

What is an example of an enzyme?

Amylase (breaks down starch).

What are protein functions?

Structural (keratin), transport (hemoglobin), defense (antibodies), hormones (insulin), enzymes, contractile (actin, myosin), storage (albumin).

What are nucleic acids?

DNA and RNA, macromolecules that store and transmit genetic information.

What is a nucleotide made of?

Nitrogenous base, pentose sugar, phosphate group.

What are purines?

Adenine and guanine (double-ring bases).

What are pyrimidines?

Cytosine, thymine, uracil (single-ring bases).

What sugar is in DNA? RNA?

DNA: deoxyribose; RNA: ribose.

What are DNA base-pairing rules?

A–T, G–C.

What is RNA base-pairing?

A–U, G–C.

What is the structure of DNA?

Double helix, antiparallel strands, complementary base pairing.