Biology Fundamentals

• This text dives into the levels of biological organization, domains of life, cell structures, organic compounds, and cell functions.

Levels of Organization

• Atom: The fundamental unit of matter.
• Molecule: A cluster of atoms held together by chemical bonds.
• Organelle: Specialized structures within cells that perform specific functions.
• Cell: The basic unit of life, capable of independent existence.
• Tissue: A group of similar cells working together for a specific function.
• Organ: A structure composed of different tissues performing a common function.
• Organ System: A group of organs working together to carry out particular functions.
• Organism: An individual living entity.
• Population: A group of the same species living in the same area.
• Community: All the different populations living together in an area.
• Ecosystem: The interaction between living organisms and their physical environment.
• Biosphere: The global sum of all ecosystems, representing the zone of life on Earth.

Domains of Life

• Bacteria: Single-celled prokaryotes, examples include E. coli and Streptococcus.
• Archaea: Single-celled prokaryotes thriving in extreme environments, such as thermophiles and halophiles.
• Eukarya: Includes organisms with eukaryotic cells (cells with a nucleus)

Kingdoms of Eukarya

• Protists: Includes organisms like Amoeba and Algae.
• Fungi: Includes organisms like mushrooms and yeast.
• Plantae: Includes organisms like trees and flowers.
• Animalia: Includes organisms like mammals, birds and fish.

Prokaryotic vs. Eukaryotic Cells

• Prokaryotic cells have no nucleus or membrane-bound organelles.
• Prokaryotic cells are smaller and simpler, examples include bacteria and archaea.
• Eukaryotic cells possess a nucleus and membrane-bound organelles.
• Eukaryotic cells are larger and more complex, examples include animals, plants, and fungi.

Characteristics of Organisms by Domain

• Bacteria are single-celled and lack a nucleus, found in various environments, with some causing diseases.
• Archaea are single-celled, lack a nucleus, and thrive in extreme conditions like hot springs.
• Eukarya can be single or multi-cellular, possess a nucleus, examples includes plants, animals, fungi, and protists.

Kingdoms of Domain Eukarya

• Protista: Mostly single-celled organisms (e.g., algae, protozoa).
• Fungi: Can be multicellular or unicellular, absorb nutrients (e.g., mushrooms, yeast).
• Plantae: Multicellular organisms producing food through photosynthesis (e.g., trees, flowers).
• Animalia: Multicellular, heterotrophic organisms capable of movement (e.g., humans, lions).

Food Acquisition by Kingdom

• Protists: Autotrophic via photosynthesis or heterotrophic via ingestion.
• Fungi: Absorb nutrients from dead or decaying matter.
• Plantae: Autotrophic, producing food through photosynthesis.
• Animalia: Heterotrophic, consuming other organisms for sustenance.

Common Features of Life

• Organization: All living things are composed of cells.
• Metabolism: Living organisms utilize energy.
• Growth and Development: Organisms grow and develop over time.
• Homeostasis: Maintenance of a stable internal environment.
• Reproduction: The ability to produce offspring.
• Response to Stimuli: Reaction to environmental changes.
• Evolution: Adaptation to the environment over time.

Evolution

• Evolution is the change in species over time due to trait variations and natural selection.
• Reproductive success ensures the passage of genetic material to subsequent generations, enabling species survival and evolution.
• The environment determines which organisms reproduce based on traits like speed, camouflage, or disease resistance.
• Adaptation is a trait or behavior enhancing an organism's survival and reproduction in a specific environment.

Scientific Method

• Observation: Noticing a phenomenon or problem.
• Question: Asking a question about the observation.
• Hypothesis: A testable prediction based on previous knowledge.
• Experiment: Testing the hypothesis through controlled variables.
• Data Collection: Gathering results from the experiment.
• Conclusion: Interpreting the results and determining if the hypothesis was correct.
• Communication: Sharing results with the scientific community.

Hypotheses vs. Predictions

• Hypothesis: A tentative explanation or educated guess.
• Prediction: A specific outcome expected if the hypothesis is correct.

Experiment Variables

• Independent Variable: The factor changed in an experiment.
• Dependent Variable: The factor that changes due to the independent variable.
• Constants: Factors kept consistent throughout an experiment.
• Controls: A group or condition that doesn't receive experimental treatment.

Repetitions and Variations

• Repetitions in experiments are important to verify results and reduce errors.
• Variation refers to natural differences observed in populations or experiments.
• Communication in science is important for sharing findings, peer review, and furthering scientific knowledge.
• Pseudoscience includes claims that appear scientific but lack empirical evidence or rigorous methodology.
• Science does not contain "proof", it only contains evidence that supports or contradicts hypotheses.

Organic Compounds

• Organic compounds include molecules containing carbon, essential for life, such as carbohydrates, lipids, proteins, and nucleic acids.
• Life’s molecular diversity depends on the properties of carbon.
• Carbon can form four covalent bonds.

Monomers vs. Polymers

• Monomer: A single subunit that can join to form a polymer (e.g., glucose).
• Polymer: A long molecule made of repeating subunits (e.g., starch)

Disaccharides vs. Polysaccharides

• Disaccharides: Two sugar molecules bonded together (e.g., sucrose, lactose).
• Polysaccharides: Long chains of sugar molecules (e.g., starch, cellulose).

Lipids and Their Functions

• Lipids: A diverse group of hydrophobic organic molecules including fats, oils, phospholipids, and steroids.
• Lipids store energy, insulate, protect, form cell membranes, and produce hormones.

Types of Fats

• Saturated Fats: No double bonds between carbon atoms, typically solid at room temperature, found in animal fats and some plant oils.
• Unsaturated Fats: Contain one or more double bonds between carbon atoms, typically liquid at room temperature, found in plants and fish.
• Trans Fats: Created through hydrogenation, solid at room temperature, can raise bad cholesterol levels, present in some processed foods.

Phospholipids, Waxes and Steroids

• Phospholipids: Lipids with a phosphate group, amphipathic, form cell membrane bilayers.
• Waxes: Long-chain fatty acids bonded to alcohols, used for protection and waterproofing.
• Steroids: Lipids with a four-ring structure (e.g., cholesterol, hormones), regulate hormones, and stabilize cell membranes.

Cholesterol

• Cholesterol is utilized to make flexible cell membranes.
• Cholesterol is utilized to to produce steroid hormones.
• Cholesterol is utilized to synthesize bile acids to digest fats.
• Anabolic steroids mimic testosterone, increasing muscle mass and strength, but lead to potential health issues.

Proteins

• 20 different amino acids are required to make proteins in the human body.
• Amino acids are linked together by peptide bonds in a chain to form a polypeptide.
• Peptide bond: A covalent bond forms between the amino group and carboxyl group of amino acids, releasing water.
• Protein shape dictates function.
• Denaturation: Altered protein shape leads to loss of function. Enzymes must have the correct shape to bind with substrates.
• Antibodies must recognize specific pathogens.

Nucleic Acids

• Nucleic acids carry genetic information and are made of nucleotides.
• DNA (Deoxyribonucleic Acid): Stores genetic information and is used as a template for protein synthesis.
• RNA (Ribonucleic Acid): Involved in the synthesis of proteins from DNA’s instructions.

RNA vs. DNA

• DNA is double-stranded
• DNA contains deoxyribose.
• RNA is single-stranded.
• RNA contains ribose.
• DNA and RNA are made of nucleotides.
• DNA and RNA both contain genetic information.
• DNA and RNA both have adenine (A), cytosine (C), and guanine (G), but DNA has thymine (T), and RNA has uracil (U).

Cell Theory

• All living organisms are made up of cells.
• The cell is the basic unit of structure and function in living organisms.
• All cells arise from pre-existing cells through cell division.

Cell Size

• As a cell size increases, its volume grows faster than its surface area.
• Surface area allows for the exchange of nutrients and waste.
• Smaller cells have a higher surface area to volume ratio.
• Smaller cells are more efficient in exchanging materials.

Cell Membranes

• The cell membrane regulates the chemical environment.
• The membrane is selectively permeable.
• Membrane proteins involve transport, signal transduction, and enzymatic reactions.
• Phospholipids form a bilayer: hydrophobic tails face inward and hydrophilic heads face outward.
• The fluid mosaic model describes a membrane made up of phospholipids, proteins, cholesterol, and carbohydrates.
• All of these components move throughout the bilayer.

Functions of Membrane Proteins

• Transport: Proteins move substance across membranes.
• Enzyme activity: catalyze reactions.
• Signal transduction: Membrane proteins can receive signals from other cells (e.g., hormone receptors).
• Cell-cell recognition: Proteins help cells recognize and communicate with each other, often through glycoproteins.
• Intercellular joining: Membrane proteins help cells adhere to one another (e.g., in tissues).
• Attachment to the cytoskeleton and extracellular matrix: Some proteins link the membrane to internal structures (cytoskeleton) or the environment (extracellular matrix), helping the cell maintain its shape and stability.

Organelles

• Nucleus: Contains genetic material (DNA), controls cell activities.
• Mitochondria: Powerhouses of the cell, produce ATP (energy).
• Endoplasmic Reticulum (ER):
  • Rough ER: Studded with ribosomes, synthesizes proteins.
  • Smooth ER: Involved in lipid synthesis and detoxification.
• Golgi Apparatus: Modifies/sorts/packages proteins and lipids for transport.
• Lysosomes: Contain digestive enzymes to break down waste and foreign material.
• Peroxisomes: Break down fatty acids and detoxify harmful substances.
• Cytoskeleton: Provides structure and helps with cell movement.
• Ribosomes: Sites of protein synthesis.
• Chloroplasts (in plants): Perform photosynthesis, converting light energy into chemical energy.
• Cell Wall (in plants, fungi, bacteria): Provides structural support and protection.
• Endomembrane System and Protein Pathway: The endomembrane system consists of the nuclear envelope, endoplasmic reticulum (ER), Golgi apparatus, lysosomes, and vesicles.
• Rough ER: Proteins are synthesized by ribosomes on the rough ER and enter the lumen for folding.
• Transport Vesicle: The protein is packaged into a vesicle and transported to the Golgi apparatus.
• Golgi Apparatus: The protein is modified, sorted, and packaged into a vesicle.
• Exocytosis: The protein is transported via vesicle to the cell membrane, where it is secreted outside the cell.
• Mitochondria: Energy-producing organelles with an inner and outer membrane.
• Chloroplasts (in plants): The site of photosynthesis, with two membranes.

Types of Junctions in Animal Cells

• Tight Junctions: Prevent leakage of extracellular fluid between cells (e.g., in epithelial cells).
• Desmosomes: Anchoring junctions that fasten cells together and provide mechanical strength (e.g., in skin cells).
• Gap Junctions: Channels that allow communication between cells by permitting ions and small molecules to pass (e.g., in heart muscle).

Types of Junctions in Plant Cells

• Plasmodesmata: Channels that connect plant cells, allowing for communication and transport of materials.

Test your knowledge of fundamental biology concepts. This quiz covers topics such as biological organization, domains of life, cell structures, and ecological interactions. It also explores the unique characteristics of different kingdoms within the domain Eukarya.