BIO201 Final Exam Review: General Biology I Study Guide

Lecture 2: Foundations of Biology

Science as a Process of Inquiry

• Science is a systematic approach to understanding the natural world through observation, hypothesis formation, experimentation, and analysis.

• Key steps: observation, question, hypothesis, prediction, experiment, and conclusion.

• Example: Testing whether plants grow faster under blue or red light by setting up controlled experiments.

Characteristics of Living Things

• All living things share common features: order, evolutionary adaptation, response to environment, regulation, energy processing, growth and development, and reproduction.

• Example: Homeostasis in humans (regulation of body temperature).

Levels of Biological Organization

• From smallest to largest: molecule → organelle → cell → tissue → organ → organ system → organism → population → community → ecosystem → biosphere.

The Three Domains of Life

• Bacteria, Archaea, and Eukarya are the three domains.

• Animalia is a kingdom within Eukarya, not a domain.

Evolution as the Unifying Theory

• Evolution explains the unity and diversity of life; all organisms share a common ancestor.

• Natural selection is a key mechanism of evolution.

Lectures 3 & 4: Chemistry of Life

Atomic Structure

• Atoms consist of protons (positive), neutrons (neutral), and electrons (negative).

• Atomic number: number of protons; atomic mass: protons + neutrons; valence: electrons in the outer shell.

Chemical Bonds

• Covalent bonds: sharing electrons (strongest).

• Ionic bonds: transfer of electrons.

• Hydrogen bonds: attraction between polar molecules (weaker).

• Relative strength: Covalent > Ionic > Hydrogen.

Polarity and Water

• Polar covalent bonds: unequal sharing of electrons (e.g., H2O).

• Water's polarity allows hydrogen bonding, leading to unique properties (cohesion, adhesion, high specific heat).

pH Scale

• Measures hydrogen ion concentration: $pH = -\log[H^+]$

• pH < 7: acidic; pH = 7: neutral; pH > 7: basic.

Lectures 5 & 6: Biological Macromolecules

Carbon and Molecular Diversity

• Carbon forms four covalent bonds, allowing for diverse organic molecules.

Four Classes of Macromolecules

• Carbohydrates: sugars and polymers (e.g., glucose, starch).

• Lipids: fats, phospholipids, steroids (hydrophobic).

• Proteins: polymers of amino acids; structure determines function.

• Nucleic acids: DNA and RNA; store and transmit genetic information.

Carbohydrates

• Monomers: monosaccharides (e.g., glucose).

• Polymers: polysaccharides (e.g., starch, cellulose).

Lipids

• Triacylglycerol: three fatty acids + glycerol.

• Phospholipids: two fatty acids + phosphate group; form cell membranes.

• Steroids: four fused rings (e.g., cholesterol).

Nucleic Acids

• Nucleotide: sugar + phosphate + nitrogenous base.

• DNA vs. RNA: DNA has deoxyribose, RNA has ribose; DNA is double-stranded, RNA is single-stranded.

Proteins

• Amino acid structure: central carbon, amino group, carboxyl group, side chain (R group).

• Protein structure: primary, secondary, tertiary, quaternary.

• Factors influencing 3D structure: hydrogen bonds, ionic bonds, hydrophobic interactions, van der Waals forces, disulfide bridges.

Lecture 7: Cell Structure and Function

Cell Theory

• All living things are composed of cells.

• Cells are the basic unit of life.

• All cells arise from pre-existing cells.

Microscopy

• Light microscopy: living cells, lower resolution.

• Electron microscopy: higher resolution, dead cells.

Eukaryotic Cell Structure

• Organelles: nucleus, mitochondria, chloroplasts, endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes.

• Endomembrane system: interconnected membranes for synthesis and transport.

Mitochondria vs. Chloroplasts

• Both have double membranes and their own DNA.

• Mitochondria: cellular respiration; chloroplasts: photosynthesis.

Cytoskeleton

• Microtubules: cell shape, movement, chromosome separation.

• Microfilaments: cell shape, muscle contraction.

• Intermediate filaments: structural support.

Eukaryotes vs. Prokaryotes

• Eukaryotes: nucleus, membrane-bound organelles.

• Prokaryotes: no nucleus, no membrane-bound organelles.

Lecture 8: Membrane Structure and Function

Phospholipids and Membranes

• Phospholipids form bilayers; hydrophilic heads face out, hydrophobic tails face in.

Fluid Mosaic Model

• Membrane is a fluid structure with proteins embedded in or attached to a phospholipid bilayer.

Membrane Fluidity

• Cholesterol and unsaturated fatty acids increase fluidity; saturated fatty acids decrease fluidity.

Glycosylation

• Addition of carbohydrates to proteins/lipids; important for cell recognition.

Transport Across Membranes

• Small, nonpolar molecules cross easily; large or charged molecules require transport proteins.

• Passive diffusion: no energy, down concentration gradient.

• Facilitated diffusion: uses transport proteins, no energy.

• Active transport: requires energy (ATP), against gradient.

Osmosis and Tonicity

• Osmosis: diffusion of water across a membrane.

• Hypertonic: higher solute outside; cell shrinks.

• Hypotonic: lower solute outside; cell swells.

Lectures 9 & 10: Metabolism and Enzymes

Kinetic vs. Potential Energy

• Kinetic energy: energy of motion.

• Potential energy: stored energy (e.g., chemical bonds).

Laws of Thermodynamics

• 1st Law: Energy cannot be created or destroyed.

• 2nd Law: Entropy (disorder) increases in spontaneous processes.

Free Energy and Reactions

• Exergonic: releases energy, spontaneous ($\Delta G < 0$).

• Endergonic: requires energy input ($\Delta G > 0$).

ATP and Coupling

• ATP hydrolysis ($ATP \rightarrow ADP + P_i$) releases energy to drive endergonic reactions.

Enzymes

• Biological catalysts; lower activation energy.

• Optimal temperature and pH for activity.

• Competitive inhibitors: bind active site; noncompetitive inhibitors: bind elsewhere.

Catabolism vs. Anabolism

• Catabolic pathways: break down molecules, release energy.

• Anabolic pathways: build molecules, require energy.

Lectures 11 & 12: Cellular Respiration and Fermentation

Redox Reactions

• Oxidation: loss of electrons; reduction: gain of electrons.

Cellular Respiration Overview

• Overall reaction: $C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + Energy$

• Four stages: Glycolysis, Pyruvate oxidation, Citric acid cycle, Oxidative phosphorylation.

Electron Carriers

• NADH and FADH2 carry electrons to the electron transport chain (ETC).

• ATP is the main energy currency.

Electron Transport Chain and ATP Synthase

• ETC is in the inner mitochondrial membrane; creates a proton gradient.

• ATP synthase uses this gradient to synthesize ATP (chemiosmosis).

Aerobic Respiration vs. Fermentation

• Aerobic: requires oxygen, produces more ATP.

• Fermentation: no oxygen, less ATP, produces lactic acid or ethanol.

Lectures 13 & 14: Photosynthesis

Photosynthesis Overview

• Converts light energy to chemical energy in plants, algae, and some bacteria.

• Overall reaction: $6CO_2 + 6H_2O + Light \rightarrow C_6H_{12}O_6 + 6O_2$

Stages of Photosynthesis

• Light reactions: produce ATP and NADPH.

• Calvin cycle: uses ATP and NADPH to fix CO2 into sugars.

Light and Pigments

• Light energy is inversely related to wavelength (shorter wavelength = higher energy).

• Pigments absorb specific wavelengths; chlorophyll absorbs blue and red, reflects green.

ATP Production Comparison

• Both cellular respiration and photosynthesis use chemiosmosis and ATP synthase.

Lectures 15 & 16: Cell Cycle and Division

Cell Division Importance

• Essential for growth, repair, and reproduction in organisms.

Cell Cycle Stages

• Interphase (G1, S, G2), Mitosis (prophase, metaphase, anaphase, telophase), Cytokinesis.

Mitotic Spindle

• Composed of microtubules; separates chromosomes during mitosis.

Meiosis and Genetic Variation

• Meiosis produces haploid gametes; increases genetic variation via crossing over, independent assortment, and random fertilization.

Haploid vs. Diploid

• Haploid (n): one set of chromosomes; diploid (2n): two sets.

Lectures 17 & 18: Mendelian Genetics

Mendel's Experiments

• Monohybrid and dihybrid crosses revealed patterns of inheritance.

• Law of Segregation: alleles separate during gamete formation.

• Law of Independent Assortment: genes on different chromosomes assort independently.

Human Inheritance Patterns

• Some traits do not follow Mendel's laws (e.g., incomplete dominance, codominance, polygenic inheritance).

Sex Determination and Sex-Linked Genes

• Sex determined by X and Y chromosomes; X-linked recessive traits more common in males.

Lecture 19: DNA Structure and Replication

DNA Structure

• Double helix of nucleotides (A, T, C, G); antiparallel strands.

Models of Replication

• Semi-conservative: each new DNA has one old and one new strand (supported by Meselson-Stahl experiment).

DNA Replication Enzymes

• Helicase: unwinds DNA.

• Primase: synthesizes RNA primer.

• DNA polymerase III: synthesizes new DNA.

• DNA polymerase I: replaces RNA primers with DNA.

• Ligase: joins Okazaki fragments.

• Topoisomerase: relieves supercoiling.

Leading vs. Lagging Strand

• Leading: continuous synthesis; lagging: discontinuous (Okazaki fragments).

Telomerase

• Replicates ends of linear chromosomes in eukaryotes.

Lecture 20: Gene Expression

Central Dogma

• Information flow: DNA → RNA → Protein.

Transcription and Translation

• Transcription: DNA to RNA (in nucleus).

• Translation: RNA to protein (in cytoplasm/ribosome).

Genetic Code

• Triplet codons specify amino acids; universal and redundant.

RNA Processing (Eukaryotes)

• 5' cap, poly-A tail, splicing (removal of introns).

Types of RNA

• mRNA: messenger RNA, carries code.

• tRNA: transfer RNA, brings amino acids.

• rRNA: ribosomal RNA, forms ribosomes.

Lecture 21: Biomineralization and Coccolithophores

Biomineralization

• Process by which living organisms produce minerals (e.g., shells, bones).

• Can be intracellular or extracellular.

Coccolithogenesis

• Formation of calcium carbonate scales (coccoliths) in coccolithophores.

• Three steps: baseplate scale formation, nucleation, maturation, secretion.

Photosynthesis, Respiration, and Calcification

• Photosynthesis and respiration influence calcification by affecting ion availability and cellular energy.

Disruptions in Calcification

• Disruptions in any step can affect coccolith production and organism survival.

Practice Questions

• Which of the following is not a domain of life? Answer: D. Animalia

• This pH meter is measuring the solution in a beaker, which best describes the pH of the solution? Answer: (Depends on context, see pH scale above)

• Which bonding pattern is not present? Answer: (Depends on context, see protein structure above)

• This picture below is of a eukaryotic cell. Answer: (True/False, based on image)

• What is the most likely method by which a molecule enters cells? Answer: (Depends on molecule, see membrane transport above)

• This energy diagram shows a chemical reaction. This reaction... Answer: (See exergonic/endergonic definitions above)

• In this wine making kit, grape juice and yeast... Answer: B. Fermentation only occurs in the absence of oxygen

• Compare the wavelengths of purple and red light. Which photons have more energy? Answer: A. Purple

• If a cell does not pass the mitotic checkpoint, which process was likely not done correctly? Answer: B. Mitotic checkpoint

• Hemophilia is a sex-linked recessive trait... Answer: (Depends on parental genotypes, see sex-linked inheritance above)

• DNA replication enzymes: Answer: (See DNA replication enzymes above)

• If a mutation occurred in a gene that caused it to no longer proofread newly made strands, what process would be disrupted? Answer: A. Proof reading of newly made strands

• A mutation occurs prohibiting baseplate scale formation. Which process of coccolithogenesis will be disrupted? Answer: A. Baseplate scale formation