BIOL FINAL EXAM

Taxonomy

  • Definition: Taxonomy is the science of classifying organisms into categories based on shared characteristics.

  • Credited Founder: Carl Linnaeus is credited with developing the taxonomic naming system.

  • Levels of Taxonomic Organization (from largest to smallest):

    • Domain

    • Kingdom

    • Phylum

    • Class

    • Order

    • Family

    • Genus

    • Species

Characteristics of Living Organisms

  • All living organisms share several characteristics, summarized by the acronym DOGS REACH:

    • DNA

    • Organization

    • Growth and Development

    • Stability (Homeostasis)

    • Reproduction

    • Energy Processing (Metabolism)

    • Adaptation

    • Cell Structure

    • Heredity

Autotrophs vs Heterotrophs

  • Autotrophs: Organisms that produce their own food (e.g., plants through photosynthesis).

  • Heterotrophs: Organisms that rely on other organisms for food (e.g., animals).

  • Comparison: Autotrophs convert inorganic substances into organic matter, while heterotrophs consume organic matter.

Scientific Method Steps

  1. Observation

  2. Question

  3. Hypothesis Formation

  4. Experimentation

  5. Data Analysis

  6. Conclusion

  7. Communication of results

Experimental Design Terminology

  • Experimental Group: The group in an experiment that receives the treatment or condition.

  • Control Group: The group that does not receive the treatment, used as a benchmark.

  • Constants: Factors that remain unchanged throughout the experiment to ensure validity.

Hypothesis Features

  • A hypothesis must be testable and falsifiable, and it is often formulated as an if-then statement.

Periodic Table Symbols and Values

  • Represents elements, their atomic numbers, and their symbols (e.g., H for Hydrogen, O for Oxygen).

Types of Atomic Bonds

  • Ionic Bonds: Formed when electrons are transferred from one atom to another, creating ions.

  • Covalent Bonds: Formed when atoms share electrons.

  • Hydrogen Bonds: Weak attractions between a hydrogen atom and an electronegative atom.

Properties of Water

  • High specific heat, cohesion, adhesion, polarity, and solvent properties, making it essential for life.

Acids and Bases

  • Acids: Donate protons (), have a pH < 7.

  • Bases: Accept protons, have a pH > 7.

  • pH Scale: A measure of hydrogen ion concentration.

Macromolecules

  1. Carbohydrates

    • Function: Energy storage, structural support.

    • Monomer: Monosaccharides (e.g., glucose).

    • Polymer: Polysaccharides (e.g., starch, cellulose).

  2. Proteins

    • Function: Catalysts, structure, transport.

    • Monomer: Amino acids.

    • Polymer: Polypeptides.

  3. Lipids

    • Function: Energy storage, membrane structure.

    • Monomer: Fatty acids and glycerol.

    • Polymer: Triglycerides, phospholipids.

  4. Nucleic Acids

    • Function: Genetic information storage and transfer.

    • Monomer: Nucleotides.

    • Polymer: DNA and RNA.

Formation of Polymers and Monomers

  • Polymers are formed through dehydration synthesis (removing water), while monomers are released through hydrolysis (adding water).

Prokaryotic vs Eukaryotic Cells

  • Prokaryotic Cells: Lack a nucleus, are generally smaller, and include bacteria.

  • Eukaryotic Cells: Contain a nucleus, are larger, and include plants and animals.

Cellular Organelles

  • Nucleus: Stores genetic material.

  • Nucleolus: Produces ribosomes.

  • Endoplasmic Reticulum (ER): Synthesizes proteins (rough ER) and lipids (smooth ER).

  • Golgi Apparatus: Modifies and packages proteins.

  • Mitochondria: Generates ATP (energy).

  • Cell Membrane: Controls entry and exit of substances.

  • Ribosomes: Synthesize proteins.

  • Vesicles: Transport materials.

  • Vacuoles: Storage.

  • Centrioles: Involved in cell division.

  • Lysosomes: Digests waste materials.

  • Chloroplasts: Site of photosynthesis in plant cells.

  • Cell Wall: Provides structure to plant cells.

Transport Mechanisms

  • Active Transport: Requires energy to move substances against a gradient.

  • Passive Transport: Does not require energy, moves substances along a gradient.

  • Concentration Gradient: Difference in concentration of molecules across a space.

Tonicity

  • Hypotonic: Cell swells as water enters.

  • Isotonic: No net movement of water; equilibrium.

  • Hypertonic: Cell shrinks as water exits.

  • Plant vs Animal Cells: Plant cells prefer hypotonic environments, while animal cells can burst.

Energy Types

  • Potential Energy: Stored energy.

  • Kinetic Energy: Energy of motion.

  • Related Laws of Thermodynamics:

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

    • 2nd Law: Energy transformations increase entropy.

Enzymes

  • Definition: Biological catalysts that speed up reactions by lowering activation energy.

  • Components: Substrate (reactant), product (result), active site (where substrate binds), enzyme-substrate complex.

Photosynthesis

  • Purpose: Convert light energy into chemical energy.

  • Organelle: Chloroplasts.

  • Pigment: Chlorophyll.

  • Equation: 6CO<em>2+6H</em>2O+extlightenergy<br>ightarrowC<em>6H</em>12O<em>6+6O</em>26CO<em>2 + 6H</em>2O + ext{light energy} <br>ightarrow C<em>6H</em>{12}O<em>6 + 6O</em>2

  • Steps: Light-dependent reactions (occur in thylakoids) and Calvin cycle (occur in stroma).

Cellular Respiration

  • Purpose: Convert chemical energy into ATP.

  • Organelle: Mitochondria.

  • Equation: C<em>6H</em>12O<em>6+6O</em>2<br>ightarrow6CO<em>2+6H</em>2O+extenergy(ATP)C<em>6H</em>{12}O<em>6 + 6O</em>2 <br>ightarrow 6CO<em>2 + 6H</em>2O + ext{energy (ATP)}

  • Stages: Glycolysis, Krebs cycle, and Electron Transport Chain (most ATP generated here).

  • Total ATP: About 36 ATP per glucose molecule.

Aerobic vs Anaerobic Respiration

  • Aerobic: Requires oxygen; produces more ATP (e.g., cell respiration).

  • Fermentation: Occurs without oxygen; produces less ATP (e.g., yeast respiration).

Cell Cycle

  • Stages: G1 (Growth), S (Synthesis), G2 (Preparation), M (Mitosis).

  • Each stage contributes to cell division and function.

Reasons for Cell Division

  • Organisms divide for growth, repair, and reproduction; different purposes for unicellular vs multicellular organisms.

Mitosis

  • Purpose: Ensure equal distribution of genetic material.

  • Stages: Prophase, Metaphase, Anaphase, Telophase.

Mitosis vs Meiosis

  • Mitosis: Produces two identical diploid daughter cells.

  • Meiosis: Produces four non-identical haploid gametes.

  • Facilitates sexual reproduction.

Genetic Diversity Contributions of Meiosis

  • Crossing over and independent assortment contribute to genetic variability.

Mendel's Laws of Inheritance

  1. Law of Segregation: Alleles segregate during gamete formation.

  2. Law of Independent Assortment: Genes for different traits can segregate independently.

  3. Law of Dominance: Dominant alleles mask recessive alleles.

Genetic Probability in Inheritance

  • Monohybrid and Dihybrid crosses calculate the likelihood of specific traits.

  • Terms:

    • Homozygous Dominant: Two identical dominant alleles (e.g., AA).

    • Homozygous Recessive: Two identical recessive alleles (e.g., aa).

    • Heterozygous: One dominant and one recessive allele (e.g., Aa).

    • Genotype: Genetic makeup.

    • Phenotype: Observable characteristics.

    • Dominant/Recessive: Relationship between alleles.

    • Codominance: Both alleles are expressed (e.g., AB blood type).

    • Incomplete Dominance: Blending of traits (e.g., red and white flowers yielding pink).

    • Polygenic Traits: Traits controlled by multiple genes.

X-Linked Traits

  • Males are statistically more affected due to having only one X chromosome, making recessive X-linked traits more likely expressed than in females, who have two X chromosomes.

Replication, Transcription, and Translation

  • Replication: Process of copying DNA.

  • Transcription: Conversion of DNA to mRNA.

  • Translation: Synthesis of proteins from mRNA.

  • Components needed: DNA, mRNA, nucleotides, ribosomes, amino acids.

Protein Synthesis Steps

  1. DNA unwinds and is transcribed to mRNA.

  2. mRNA undergoes splicing to remove introns and join exons.

  3. Ribosomes read mRNA codons, and tRNA delivers amino acids based on anticodon pairing.

  4. Amino acids form a polypeptide chain that folds into a protein.

Operon Regulation

  • Operons are genes regulated together in prokaryotic cells, controlling gene expression based on environmental conditions.

Gene Expression Control

  • Involves transcriptional and post-transcriptional regulation in both plants and animals.

Barr Bodies

  • Barr Bodies are inactivated X chromosomes found in females, ensuring dosage compensation for X-linked genes.

Mutations in Genetic Code

  • Types:

    • Point Mutation: A single nucleotide change.

    • Frameshift Mutation: Insertions or deletions that shift reading frame.

Genetic Manipulation through Ages

  • Traditional methods include selective breeding; modern methods include genetic engineering, and potential future methods include CRISPR technology.

Cloning, PCR, Gel Electrophoresis & CRISPR

  • Cloning: Creating a genetically identical copy of an organism.

  • PCR (Polymerase Chain Reaction): Amplifying DNA sequences.

  • Gel Electrophoresis: Separating DNA fragments by size.

  • CRISPR: A revolutionary technique for editing genomes.

Dolly the Sheep

  • The first cloned mammal, demonstrating successful somatic cell nuclear transfer.