Learning Objectives

define biology and describe some of its subdisciplines

The scientific study of life...are hypothesis driven sciences, order, regulation,growth and development, energy utilization, response to the environment, reproduction, evolution

arrange properly the levels of biological organization

Atom, molecule, organelle, cell, tissue, organ, organ system, organism, population, community, ecosystem, biosphere

describe and recognize examples of the defining characteristics of life

Order - organized structures (cells, tissues, organs).

Response to stimuli - reacting to the environment (plants growing toward light).

Reproduction - producing offspring.

Growth and development - change in size and specialization.

Regulation/homeostasis - maintaining internal balance (body temperature).

Energy processing - using energy for activities (plants photosynthesize, animals eat).

Adaptation and evolution - populations change over time.

understand that the characteristics of life are manifestations of the chemical and physical properties, and interactions, of matter

Life depends on the chemistry of molecules (DNA, proteins, water) and the physics of energy transfer (respiration, photosynthesis)

grasp the five fundamental themes of biology,

Organization-life has a hierarchy of structures

Information- DNA carries instructions for life

energy and matter- organisms use and transform energy

Interactions- organisms interact with each other and the environment

Evolution- explains the unity and diversity of life

describe and order the steps of the scientific method.

Also known as hypothesis testing

Observation - notice a phenomenon

Hypothesis- make an educated guess

Experimentation- test the hypothesis

The data- interpret the results

Conclusion- accept, reject, or revise the hypothesis

arrange properly the levels of biological organization

Atom → Molecule → Organelle → Cell → Tissue → Organ → Organ system → Organism → Population → Community → Ecosystem → Biosphere

describe and recognize examples of the defining characteristics of life

Some defining characteristics: order; sensitivity/response to stimuli; reproduction; growth and development; regulation; homeostasis; energy processing; adaptation/evolution.

Examples: Plants growing towards light (response to stimulus)

Bacteria dividing (reproduction)

Human body keeping constant internal temperature (homeostasis)

Organisms using food or sunlight for energy (energy processing)

understand that the characteristics of life are manifestations of the chemical and physical properties, and interactions, of matter

Life is built from matter: atoms, molecules, macromolecules, organelles, cells. Chemical properties (like how molecules bond, enzyme activity, solubility) and physical properties (shape of molecules, membrane structure, diffusion) allow life's processes (metabolism, growth, response). Interactions among molecules (proteins, lipids, nucleic acids) underlie cell structure, signaling, and function.

grasp the five fundamental themes of biology

Organization, Information, Energy and Matter, Interactions, Evolution

describe and order the steps of the scientific method.

Observation, Hypothesis, Experiment / Test, Analyze Data, Conclusion

Define the scientific method

The scientific method is a systematic process used to investigate observations, solve problems, and test hypotheses.

Observation

Hypothesis

Experiment

Data Collection

Conclusion

Describe a valid hypothesis

Testable (can be supported or refuted by experiments)

Falsifiable (can potentially be proven wrong)

Specific and clear

Contrast experimental and control variables

Experimental-The group or condition where the variable is being tested

Control-The standard or baseline group used for comparison

Contrast independent and dependent variables

Independent-The variable that is changed or manipulated

Dependent-The variable that is measured or observed

Independent Variable: Amount of sunlight

Dependent Variable: Plant height

Contrast quantitative and qualitative result

Quantitative Numerical data "The plant grew 5 cm"

Qualitative Descriptive data (non-numerical) "The leaves turned darker green"

Contrast discrete and continuous data

Discrete- Countable values, often whole numbers ....Number of students, number of petals

Continuous-Measurable values that can take any value...Height, temperature, time

Explain the pH scale - know what value(s) are acidic, neutral, and basic

The pH scale ranges from 0 to 14 and measures the concentration of hydrogen ions (H⁺) in a solution.

pH < 7 → Acidic (e.g., lemon juice)

pH = 7 → Neutral (e.g., pure water)

pH > 7 → Basic/Alkaline (e.g., baking soda solution)

Determine the volume of a liquid with a graduate cylinder

Place the graduated cylinder on a flat surface.

View the liquid level at eye level.

Read the bottom of the meniscus (the curve at the surface of the liquid).

Use the smallest marked unit for precision.

Explain why experiments are replicated

Replication ensures: Reliability of results Elimination of errors or outliers

Confidence in the validity of conclusions

In short: More trials = stronger, more trustworthy results.

Determine whether a hypothesis will be accepted or rejected given a graph of results

Look at the trend in the data.

See whether the results support the prediction made in the hypothesis.

If the data matches the prediction → Accept the hypothesis.

If not → Reject the hypothesis.

state what happens to matter during chemical reactions

Matter is neither created nor destroyed, but rearranged.

differentiate organic and inorganic molecules

Organic Molecules- contain carbon-hydrogen (C-H) bonds...Typically found in living organisms Examples: Glucose, DNA, Proteins

Inorganic Molecules- Do not contain C-H bonds...Found in non-living systems (some in living things) Examples: Water (H₂O), Salt (NaCl), CO₂

list the four chemical elements that make up the majority of mass of living things

Carbon (C)

Hydrogen (H)

Oxygen (O)

Nitrogen (N)

describe atomic structure

Atoms are made of:

Protons (positive charge, in nucleus)

Neutrons (no charge, in nucleus)

Electrons (negative charge, orbiting nucleus)

The number of protons = number of electrons in a neutral atom.

state what all is summarized by a chemical element's atomic number

The atomic number tells you: The number of protons in an atom Also equals the number of electrons in a neutral atom Defines the element (e.g., Carbon = 6 protons)

explain what a chemical bond is and when atoms in bonds are most stable

A chemical bond is a force that holds atoms together.

Atoms form bonds to become more stable, usually when they have full outer electron shells (e.g., 8 electrons in outer shell — the "octet rule").

contrast ionic and covalent bonds

Ionic Bond- Electrons are transferred, Occurs between metal + non-metal, Forms ions (charged atoms) Example: NaCl (table salt)

Covalent Bond- Electrons are shared, Occurs between non-metals Forms molecules, Example: H₂O (water)

explain the difference between nonpolar covalent and polar covalent bonds

Nonpolar Covalent- Electrons are shared equally, No partial charges on atoms, Example: O₂, CH₄

Polar Covalent- Electrons are shared unequally, Causes partial + and - charges Example: H₂O (oxygen is more electronegative)

summarize the importance of water to living things

Water is essential for life because it: Is a universal solvent (dissolves many substances) Has high heat capacity (stabilizes temperature) Is involved in chemical reactions (e.g., hydrolysis) Supports transport and structure in cells Allows for cohesion and adhesion (important in plant transport)

contrast hydrophilic and hydrophobic molecules

Hydrophilic- "water loving" Dissolves well in water usually polar or charged Example: salt & sugar

Hydrophobic- "water fearing" does not dissolve well in water usually nonpolar, Example: oil & fats

recall why buffers are important in biological systems

Buffers maintain stable pH levels in living organisms. They prevent drastic pH changes, which can: Disrupt enzyme activity Damage cells Interfere with biochemical reactions Example: Blood contains buffers to maintain pH around 7.4

state the bonding properties of carbon

Carbon has four electrons in its outer shell, which allows it to form up to four covalent bonds. It can bond with hydrogen, oxygen, nitrogen, phosphorus, sulfur, or with other carbon atoms. Carbon-carbon bonds can be single, double, or triple. Carbon backbones can form chains (straight or branched) or rings. These bonding abilities give carbon huge versatility in forming complex organic molecules.

identify functional groups with biological importance

Important functional groups include: hydroxyl (-OH), methyl (-CH₃), carbonyl (C=O), carboxyl (-COOH), amino (-NH₂), phosphate (-PO₄), and sulfhydryl (-SH). These groups influence polarity, acidity/basicity, bonding, and how molecules interact in cells (e.g., in proteins, lipids, nucleic acids, carbohydrates).

state the biological macromolecules that make up cell

The four major classes of biological macromolecules are: carbohydrates, lipids, proteins, and nucleic acids. These make up most of the structure and functional machinery of cells.

know the monomers the compose the polymers of biological importance (biological macromolecules)

Carbohydrates → monosaccharides (e.g. glucose)

Proteins → amino acids

Nucleic acids → nucleotides

Lipids are not built from repeating identical monomers in the same way, but often composed of fatty acids + glycerol (or other backbones)

recall chemical reactions that synthesize and breakdown polymers

Two main types of reactions:

Dehydration synthesis (also called condensation): building polymers from monomers by removing water.

Hydrolysis: breaking polymers into monomers by adding water.

know the classification of carbohydrates and examples of each

Carbohydrates are classified based on number of sugar units:

Monosaccharides: single sugars (e.g. glucose, fructose)

Disaccharides: two monosaccharides joined (e.g. sucrose, maltose)

Polysaccharides: many sugar units (e.g. starch, glycogen, cellulose)

know the classification of lipids and the structure of each

Triglycerides: glycerol + three fatty acids; can be saturated or unsaturated

Phospholipids: glycerol + two fatty acids + phosphate group + often another polar head; have hydrophilic head + hydrophobic tails

Steroids: carbon rings (four fused rings) with different functional side groups

Waxes: long chain fatty acids + long chain alcohols; very hydrophobic

describe the primary, secondary, tertiary, and quaternary structure of proteins

Primary structure: the linear sequence of amino acids in a polypeptide chain

Secondary structure: local folding patterns such as alpha helices and beta-pleated sheets, stabilized by hydrogen bonds

Tertiary structure: the overall 3-D shape of a single polypeptide chain due to side-chain interactions (hydrophobic, ionic, hydrogen bonding, disulfide bridges, etc.)

Quaternary structure: the arrangement and interaction of two or more polypeptide chains (subunits) into a larger functional protein

list the critical roles proteins play in living organisms

Enzymes: catalyze biochemical reactions

Structural support: building cell and tissue structure (e.g. collagen, cytoskeleton)

Transport: carrying molecules (e.g. hemoglobin transporting oxygen)

Signaling / messenger / regulatory: hormones, receptors, gene regulation

Immune defense: antibodies

Movement: contractile proteins in muscles etc.

Storage: storing nutrients or molecules

contrast the structure and nucleotide composition of DNA and RNA

DNA: usually double-stranded; sugar is deoxyribose (lacks hydroxyl group on the 2′ carbon); bases are adenine, thymine, cytosine, guanine

RNA: usually single-stranded; sugar is ribose (has hydroxyl group on 2′ carbon); bases are adenine, uracil (instead of thymine), cytosine, guanine

recall the Cell Theory

All living organisms are composed of one or more cells.

The cell is the basic unit of structure and function in living organisms.All cells arise from pre-existing cells by division. Energy flow (metabolism and biochemistry) occurs within cells. Hereditary information (DNA) is passed from cell to cell during cell division. All cells have the same basic chemical composition. All basic chemical and physiological functions are carried out inside the cells. Cell activity depends on the activities of subcellular structures within the cell.

state the features shared by all cells

A plasma membrane that regulates material entry and exit.

Cytoplasm, a jelly-like substance where cellular components are suspended.

Ribosomes, structures responsible for protein synthesis.

Genetic material (DNA or RNA) that carries hereditary information.

State, properly order, and explain the four steps hypothesizing the origin of cells in Earth's ancient, reducing atmosphere

Formation of Simple Organic Molecules: Simple molecules like methane and ammonia reacted under energy sources (e.g., lightning) to form organic compounds.

Formation of Complex Organic Molecules: These simple molecules polymerized to form complex molecules like amino acids and nucleotides.

Formation of Protocells: These complex molecules became enclosed in lipid membranes, forming protocells with basic metabolic functions.

Development of Self-Replicating Systems: Within protocells, molecules like RNA developed the ability to replicate, leading to the emergence of true cells.

connect these hypotheses to the origin of prokaryotes

The hypotheses suggest that the first true cells were simple, single-celled organisms without a nucleus, resembling modern prokaryotes. These early cells likely evolved into the diverse forms of prokaryotes observed today.

contrast prokaryotic and eukaryotic cells.

Prokaryotic

Nucleus: Lack a true nucleus; genetic material is free in the cytoplasm.Organelles: Do not have membrane-bound organelles.Size: Generally smaller, ranging from 0.1-5.0 µm.Examples: Bacteria and archaea.

Eukaryotic

Nucleus: Contain a true nucleus enclosed by a membrane

Organelles: Have membrane-bound organelles (e.g., mitochondria, endoplasmic reticulum).

Size: Larger, typically 10-100 µm.

Examples: Plants, animals, fungi, and protists.

Differentiate plant and animal cells.

Plant Cells:

Cell Wall: Present; provides structural support and protection.

Chloroplasts: Contain chlorophyll for photosynthesis.

Vacuole: Large central vacuole; maintains cell rigidity and stores nutrients.

Shape: Generally rectangular or fixed shape.

Animal Cells:

Cell Wall: Absent; only a plasma membrane is present.

Chloroplasts: Absent; do not perform photosynthesis.

Vacuole: Small or absent; storage and waste disposal.

Shape: Varied shapes; often round or irregular.

explain the features and function of the cytosol

The cytosol is the aqueous component of the cytoplasm, containing water, dissolved ions, small molecules, and proteins. It serves as the site for many metabolic pathways and provides a medium for the suspension of organelles and molecules.

understand the structure and role of the nucleus in eukaryotic cells

The nucleus is a membrane-bound organelle that contains the cell's genetic material (DNA). It controls gene expression and mediates the replication of DNA during the cell cycle. The nucleus is surrounded by a double membrane called the nuclear envelope, which contains nuclear pores for material exchange.

state the organelles of the endomembrane system in eukaryotic cells and explain the function of each

Nuclear Envelope: Surrounds the nucleus, separating it from the cytoplasm.

Endoplasmic Reticulum (ER):

Rough ER: Studded with ribosomes; synthesizes proteins.

Smooth ER: Synthesizes lipids; detoxifies certain chemicals.

Golgi Apparatus: Modifies, sorts, and packages proteins and lipids for storage or transport.

Lysosomes: Contain enzymes for digestion of macromolecules.

Vesicles: Transport materials between organelles.

state the semiautonomous organelles of eukaryotic cells and explain the origin of each

Mitochondria: Powerhouse of the cell; involved in energy production.

Chloroplasts: Found in plants; involved in photosynthesis.

These organelles are believed to have originated from free-living prokaryotes that formed symbiotic relationships with ancestral eukaryotic cells, a theory known as endosymbiosis.

recall the biochemical and structural evidence supporting the endosymbiotic origins of mitochondria and chloroplasts

DNA: Both mitochondria and chloroplasts contain their own circular DNA, similar to bacterial genomes.

Ribosomes: They have ribosomes similar to those of prokaryotes.

Reproduction: They replicate independently within the cell through a process resembling binary fission.

Double Membrane: The double membrane structure is consistent with an engulfment mechanism.

list the 3 important functions of biological membranes covered in BIO 1134 Biology I

Barrier: They act as a barrier to separate the internal environment of the cell from the external environment.

Transport: They regulate the transport of substances in and out of the cell, allowing selective permeability.

Communication: They facilitate communication between cells and their environment through receptors and signaling pathways

draw and describe the structure of a biological membrane

Phospholipid Bilayer: Hydrophilic (water-attracting) heads face outward, while hydrophobic (water-repelling) tails face inward, forming a semi-permeable membrane.

Proteins: Integral proteins span the membrane, while peripheral proteins are attached to the exterior or interior surfaces.

Carbohydrates: Glycoproteins and glycolipids protrude from the membrane surface, involved in cell recognition and signaling.

Cholesterol: Interspersed within the bilayer, it modulates membrane fluidity.

explain what is meant by "fluid mosaic" in the description of biological membranes

The "fluid mosaic model" describes the biological membrane as a dynamic structure:

Fluid: The lipid bilayer is flexible, allowing lateral movement of components.

Mosaic: The membrane is a patchwork of proteins, lipids, and carbohydrates, each with specific functions.

contrast transmembrane proteins and lipid-anchored proteins

Transmembrane Proteins: Span the entire lipid bilayer, with regions exposed on both the exterior and interior surfaces of the cell.

Lipid-Anchored Proteins: Covalently attached to lipids embedded in the bilayer, but do not span the membrane.

recall the location of peripheral membrane proteins on biological membranes

Peripheral membrane proteins are located on the exterior or interior surfaces of the lipid bilayer, often attached to integral proteins or phospholipids through non-covalent interactions.

describe how phospholipids can move within biological membranes

Lateral Diffusion: Phospholipids move sideways within the same leaflet of the bilayer.

Flip-Flop: Phospholipids move from one leaflet to the other; this occurs rarely and requires energy.

describe how transmembrane proteins can move within biological membranes

Transmembrane proteins can move laterally within the lipid bilayer, though their movement may be restricted by interactions with the cytoskeleton, extracellular matrix, or other proteins.

list factors that influence the fluidity of biological membranes

Temperature: Higher temperatures increase fluidity; lower temperatures decrease it.

Fatty Acid Composition: Unsaturated fatty acids increase fluidity; saturated fatty acids decrease it.

Cholesterol Content: Moderate temperatures, cholesterol maintains fluidity; at low temperatures, it prevents solidification.

know where components of biological membranes - phospholipids, transmembrane proteins, and carbohydrates - are synthesized in eukaryotic cells

In eukaryotic cells:

Phospholipids: Synthesized in the smooth endoplasmic reticulum.

Transmembrane Proteins: Synthesized in the rough endoplasmic reticulum and modified in the Golgi apparatus.

Carbohydrates: Synthesized in the Golgi apparatus and attached to proteins or lipids to form glycoproteins and glycolipids.

define a gradient and how this concept relates to passive and active transport of substances across a biological membrane

A gradient refers to a difference in concentration, charge, or pressure across a membrane.

Passive Transport: Substances move along their concentration gradient (from high to low concentration) without energy expenditure.

Active Transport: Substances move against their concentration gradient (from low to high concentration) requiring energy, typically in the form of ATP.

state the importance of cell membrane selective permeability

Selective permeability allows the cell membrane to regulate the entry and exit of substances, maintaining homeostasis by permitting essential nutrients in, removing waste products, and preventing harmful substances from entering.

list the four factors that determine a solute's ability to cross the phospholipid bilayer

Size: Smaller molecules pass more easily.

Polarity: Nonpolar molecules pass more easily than polar molecules.

Charge: Charged ions have difficulty passing without assistance.

Solubility: Lipophilic (fat-soluble) substances pass more easily than hydrophilic (water-soluble) substances.

state and explain the two types of gradients maintained across biological membranes

Concentration Gradient: Difference in the concentration of a substance across a membrane.

Electrochemical Gradient: Combination of concentration gradient and electrical charge difference across a membrane, affecting ion movement

compare the three types of solution tonicity (isotonic, hypertonic, and hypotonic)

Tonicity refers to the relative concentration of solutes in solutions:

Isotonic: Solute concentrations are equal inside and outside the cell; no net movement of water.

Hypertonic: Higher solute concentration outside the cell; water moves out, causing cell shrinkage.

Hypotonic: Lower solute concentration outside the cell; water moves in, causing cell swelling or bursting.

compare the roles of channel proteins and the three types of transporter proteins in facilitated diffusion

Channel Proteins: Form pores that allow specific ions or molecules to pass through.

Carrier Proteins: Bind to specific molecules and undergo conformational changes to transport them across the membrane.

Uniporters: Transport a single type of molecule.

Symporters: Transport two types of molecules in the same direction.

Antiporters: Transport two types of molecules in opposite directions.

contrast exocytosis and endocytosis

Exocytosis and endocytosis are processes that move large molecules across the cell membrane:

Exocytosis: Vesicles containing substances fuse with the plasma membrane, releasing their contents outside the cell.

Endocytosis: The cell membrane engulfs external substances, forming vesicles that bring them into the cell.

Recall what specimens or cell structures can be viewed with dissecting, compound, and scanning electron microscopes

Dissecting Microscope: Ideal for viewing larger, three-dimensional specimens such as insects, leaves, and small mechanical parts.

Compound Microscope: Used for observing smaller, transparent specimens like cells, bacteria, and thin tissue sections.

Scanning Electron Microscope (SEM): Provides high-resolution images of surfaces of specimens, such as the surface of a leaf or the texture of a material, by scanning with a focused electron beam.

Know how to properly carry a dissecting and compound microscope

Dissecting Microscope: Grasp the arm with one hand and support the base with the other hand.

Compound Microscope: Hold the arm securely with both hands, ensuring not to touch the eyepiece tube, stage, or focus knobs to prevent damage.

Identify the oculars, objective(s), focus knob(s), and stage of dissecting and compound microscopes

Oculars (Eyepieces): Lenses you look through; typically 10x magnification.

Objectives: Lenses with varying magnifications (e.g., 4x, 10x, 40x) mounted on a rotating nosepiece.

Focus Knobs: Coarse and fine knobs used to adjust the focus of the specimen.

Stage: Platform where the slide or specimen is placed for viewing.

Know whether or not a dissecting and compound microscope inverts the image (i.e., shows the image upside down and backwards)

Dissecting Microscope: Typically does not invert the image; provides a three-dimensional view.Compound Microscope: Inverts the image; specimens appear upside down and reversed due to the optical path.

Draw and label representative plant and animal cells

Plant Cell: Includes structures like cell wall, chloroplasts, central vacuole, nucleus, and mitochondria.

Animal Cell: Contains structures such as plasma membrane, nucleus, mitochondria, and lysosomes.

Calculate total magnification given the power of the ocular and objective lens

Total Magnification = Ocular Magnification × Objective Magnification

For example, with a 10x ocular lens and a 40x objective lens:

10x × 40x = 400x total magnification

Define resolution

Resolution is the ability of a microscope to distinguish two points as separate entities; higher resolution allows for clearer and more detailed images.

Define contrast

Contrast refers to the difference in light intensity between the specimen and the background, enhancing the visibility of structures within the specimen.

Obtain clear images using dissecting and compound microscopes

Dissecting Microscope: Adjust the zoom and focus to obtain a sharp, three-dimensional view.

Compound Microscope: Use appropriate lighting, adjust the condenser and diaphragm to control contrast, and fine-tune the focus for clarity.