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General Biology Exam 1 Key Concepts

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Termini in questo insieme (28)

  • Hierarchy of Life levels

    From smallest to largest: Atom, Molecule, Organelle, Cell, Tissue, Organ, Organ system, Organism, Population, Community, Ecosystem, Biosphere.

  • Emergent property

    A new property that arises at a higher level of organization due to interactions among parts, e.g., flight emerges at the organism level.

  • Seven characteristics of life

    Organization, energy processing, reproduction, growth and development, response to stimuli, regulation, evolutionary adaptation.

  • Scientific method steps

    Make observations, ask a question, form a hypothesis, design controlled experiment, collect data, analyze data and test null hypothesis.

  • Good hypothesis criteria

    Specific, testable, falsifiable. Null hypothesis states no effect; alternative states an effect exists.

  • Ionic bond

    Electron transfer creates cation (+) and anion (-) that attract each other; often between atoms with very different electronegativities.

  • Polar covalent bond

    Electrons shared unequally, creating partial charges (δ+ and δ-); common in O-H and N-H bonds.

  • Nonpolar covalent bond

    Electrons shared equally or nearly equally; common in C-C and C-H bonds.

  • Hydrogen bond

    Weak attraction between partial positive H and electronegative atoms (F, O, N); important in water and DNA base pairing.

  • Four emergent properties of water

    Cohesion/adhesion, temperature moderation, expansion on freezing, versatile solvent.

  • pH scale basics

    Measures H+ concentration; 1 unit change = 10x change in H+. Acid increases H+, lowers pH; base decreases H+, raises pH.

  • Functional groups to recognize

    Hydroxyl (-OH), Carbonyl (C=O), Carboxyl (-COOH), Amino (-NH2), Sulfhydryl (-SH), Phosphate (-OPO3^2-), Methyl (-CH3).

  • Condensation vs. hydrolysis

    Condensation (dehydration) joins monomers by removing water; hydrolysis breaks bonds by adding water.

  • Carbohydrate monomer and linkage

    Monosaccharides linked by glycosidic bonds form polysaccharides.

  • Difference between starch, glycogen, and cellulose

    Starch: plant energy storage, alpha glucose; Glycogen: animal energy storage, highly branched alpha glucose; Cellulose: plant structural support, beta glucose.

  • Saturated vs. unsaturated fatty acids

    Saturated: no C=C double bonds, straight tails, tightly packed; Unsaturated: ≥1 C=C double bonds, kinks, less packing, more fluid.

  • Phospholipid structure and membrane formation

    Amphipathic: hydrophilic phosphate head and hydrophobic fatty acid tails; self-assemble into bilayers in water.

  • Protein monomer and bond type

    Amino acids linked by peptide bonds form polypeptides.

  • Four levels of protein structure

    Primary: amino acid sequence; Secondary: local folding (alpha helices, beta sheets); Tertiary: 3D shape from R-group interactions; Quaternary: multiple polypeptide subunits.

  • Denaturation effects on proteins

    Disrupts secondary, tertiary, or quaternary structure by changes in temperature, pH, or polarity; primary sequence usually remains intact.

  • Nucleotide components

    5-carbon sugar + phosphate group + nitrogenous base.

  • DNA vs. RNA differences

    DNA: deoxyribose sugar, double-stranded, bases A,T,G,C; RNA: ribose sugar, single-stranded, bases A,U,G,C.

  • Purines vs. pyrimidines

    Purines: adenine (A), guanine (G) with two rings; Pyrimidines: cytosine (C), thymine (T), uracil (U) with one ring.

  • Central dogma of molecular biology

    DNA is transcribed to RNA, which is translated into protein.

  • Endosymbiotic theory

    Mitochondria and chloroplasts originated from engulfed free-living prokaryotes, supported by their own DNA and ribosomes.

  • Key differences between prokaryotes and eukaryotes

    Prokaryotes lack membrane-bound nucleus and organelles; eukaryotes have both and are generally larger and compartmentalized.

  • Protein secretion pathway

    Polypeptide synthesized on bound ribosome → rough ER → transport vesicle → Golgi apparatus → vesicle → plasma membrane or secretion.

  • Plant cell-specific structures

    Cell wall, chloroplasts, large central vacuole, plasmodesmata.