Biological Sciences Study Guide

A comprehensive set of flashcards based on key concepts from chemistry, biology, evolution, and scientific methodology for exam preparation.

Molecule Movement

Molecules move in gases and liquids primarily through diffusion, which is influenced by temperature.

Temperature Effect

Higher temperatures increase molecular motion, leading to faster diffusion rates.

Molecular Motion in Biology

Examples include cellular respiration and nutrient absorption in cells.

Fluid Mosaic Model

A model that describes the structure of cell membranes as a mosaic of various components, including lipids and proteins.

Plasma Membrane

A selectively permeable barrier that encloses a cell, composed of a lipid bilayer with embedded proteins.

Endomembrane System

A group of membrane-bound organelles involved in the synthesis and transport of proteins and lipids.

Exocytosis

The process by which cells export proteins and other molecules via vesicles fusing with the plasma membrane.

Membrane-bound Organelles

Organelles surrounded by membranes, including the nucleus, mitochondria, and endoplasmic reticulum.

Selectively Permeable Membrane

A membrane that allows certain molecules to pass while blocking others.

Movement Predictions

Small, nonpolar molecules can readily cross the plasma membrane, while polar and larger molecules require specific transport proteins.

Osmosis

The diffusion of water across a selectively permeable membrane.

Isotonic Solution

A solution where the concentration of solutes is equal inside and outside the cell, resulting in no net water movement.

Hypertonic Solution

A solution with a higher solute concentration compared to the cell, causing cell shrinkage due to water loss.

Hypotonic Solution

A solution with a lower solute concentration compared to the cell, causing cell swelling and potential burst.

Facilitated Diffusion

The transport of molecules across a membrane via proteins, without energy expenditure.

Active Transport

The movement of molecules against their concentration gradient, requiring energy input.

Chemotaxis

Movement of cells in response to chemical gradients.

Quorum Sensing

Communication among bacteria to coordinate behavior based on population density.

Autocrine Signaling

A form of signaling where a cell targets itself.

Paracrine Signaling

Cell signaling where a cell targets nearby cells.

Endocrine Signaling

Signaling that involves hormones released into the bloodstream affecting distant cells.

Receptor

Protein molecules that receive signaling molecules (ligands) to initiate a response.

Ligand

A molecule that binds to a receptor to trigger a response.

Target Cell

A cell that expresses a receptor for a specific ligand.

Plasmolysis

The process where cells lose water in a hypertonic solution, causing the cell membrane to pull away from the cell wall.

Bacterial Cell Environments

Hypertonic environments lead to plasmolysis, isotonic environments maintain cell integrity, and hypotonic environments may cause cell lysis.

Food Preservation

Uses hypertonic conditions (salting or drying) to inhibit microbial growth.

Animal Cells

Eukaryotic cells characterized by the absence of a cell wall and usually contain lysosomes.

Plant Cells

Eukaryotic cells with a rigid cell wall, chloroplasts, and large vacuoles.

Organelles

Specialized structures within a cell, such as the nucleus and mitochondria, each with unique functions.

Nucleus

The organelle that houses the cell's genetic material.

Mitochondria

The powerhouse of the cell, producing ATP through cellular respiration.

Ribosomes

Molecular machines that synthesize proteins from amino acids.

Golgi Apparatus

An organelle that modifies, sorts, and packages proteins and lipids for transport.

Rough Endoplasmic Reticulum

A type of endoplasmic reticulum studded with ribosomes involved in protein synthesis.

Smooth Endoplasmic Reticulum

An endoplasmic reticulum without ribosomes, involved in lipid synthesis.

Vacuole

A membrane-bound sac used for storage of substances in a cell.

Centrosome

An organelle that organizes microtubules and provides structure to a cell.

Lysosomes

Organelles containing enzymes for digestion and waste removal.

Cytoskeleton

A network of fibers that provides structural support and shape to a cell.

Microtubules

Cylindrical structures that can support and shape cells and are involved in intracellular transport.

Microfilaments

Thin filaments of actin involved in cell movement and structure.

Flagella

Long, whip-like structures that aid in cell movement.

Cilia

Short, hair-like structures on the cell surface that help in movement and sensing the environment.

Gap Junctions

Specialized intercellular connections that allow communication between adjacent cells.

Tight Junctions

Connections between cells that create a barrier to prevent leakage of substances.

Desmosomes

Anchoring junctions that link adjacent cells together.

Cytosol

The fluid component of the cytoplasm, excluding organelles.

Cytoplasm

The entire contents of the cell within the membrane, excluding the nucleus.

Cell Wall

A rigid outer layer found in plant cells that provides structural support.

Chloroplast

An organelle in plant cells responsible for photosynthesis.

Macromolecule

Large biological molecules including carbohydrates, lipids, proteins, and nucleic acids.

Carbohydrates

Organic compounds made of carbon, hydrogen, and oxygen, serving as energy sources.

Lipids

Hydrophobic molecules that include fats and oils, essential for membrane structure.

Proteins

Polymers of amino acids that perform numerous functions in the cell.

Nucleic Acids

Macromolecules that store and transmit genetic information, such as DNA and RNA.

Macromolecule Location

Macromolecules are found throughout the cell, participating in various cellular functions.

Monomer

The basic building block of a macromolecule.

Polymer

A large molecule composed of many repeating monomer units.

Endosymbiosis

A theory explaining the origin of mitochondria and chloroplasts from engulfed prokaryotic cells.

Endosymbiotic Theory

The hypothesis that mitochondria and chloroplasts originated as free-living bacteria.

Evidence for Endosymbiosis

Mitochondria and chloroplasts contain their own DNA, similar to bacteria.

DNA Sequences

Support the endosymbiotic theory by showing genetic similarities to prokaryotic DNA.

Properties of Water

High specific heat, cohesion, adhesion, and solvent abilities, crucial for biological systems.

Water Examples in Biology

Water's role in thermoregulation, as a solvent in biochemical reactions, and in maintaining cell turgor.

Microbes and Water Quality

Microorganisms can impact water quality by decomposing organic material and influencing nutrient cycles.

Biological Organization Levels

The hierarchy from molecules to organisms, including cells, tissues, organs, and systems.

Characteristics of Life

Criteria that define life, including metabolism, growth, reproduction, and response to stimuli.

Atoms

The smallest unit of matter that retains the properties of an element.

Protons

Positively charged particles found in the nucleus of an atom.

Neutrons

Neutral particles found in the nucleus of an atom.

Electrons

Negatively charged particles that orbit the nucleus of an atom.

Element

A pure substance made of only one type of atom.

Molecule

Two or more atoms bonded together.

Nonpolar Covalent Bonds

Bonds formed when atoms share electrons equally.

Polar Covalent Bonds

Bonds formed when atoms share electrons unequally, leading to partial charges.

Ionic Bonds

Bonds formed when electrons are transferred from one atom to another, creating charged ions.

Chemical Bonds Importance

Chemical bonds are crucial for forming molecules and compounds essential for life.

Electronegativity

The tendency of an atom to attract electrons, influencing bond formation.

Polar Molecules

Molecules that have regions of partial positive and negative charge due to unequal sharing of electrons.

Importance of Water as Polar Molecule

Water's polarity allows it to form hydrogen bonds, making it an excellent solvent.

Theory

A well-substantiated explanation of some aspect of the natural world that can be tested.

Spontaneous Generation Definition

The outdated hypothesis that life can arise from non-living matter.

Cell Theory

The theory stating that all living organisms are composed of cells and that cells arise from pre-existing cells.

Spontaneous Generation vs. Cell Theory

Cell theory contradicts spontaneous generation by asserting that all cells originate from other cells.

Prokaryotic Cells

Simple, unicellular organisms lacking a nucleus and membrane-bound organelles.

Eukaryotic Cells

More complex cells with a nucleus and membrane-bound organelles.

Prokaryotic vs. Eukaryotic Cells

Prokaryotic cells are generally smaller and simpler compared to the larger, more complex eukaryotic cells.

Taxonomy Definition

The science of classifying organisms into groups based on similarities.

Characteristics of Taxonomic Classification

Traits used for classification include morphology, genetics, and evolutionary history.

Phylogeny Definition

The study of the evolutionary history and relationships among individuals or groups of organisms.

Three Domains of Life

Bacteria, Archaea, and Eukarya, which represent the major branches of life.

Small Subunit Ribosomal RNA

A crucial gene used for determining phylogenetic relationships among organisms.

Binomial Nomenclature

A two-part naming system for organisms, consisting of the genus and species names.

Phylogenetic Tree

A diagram that represents evolutionary relationships among various biological species.

Scientific Method Steps

Steps include observation, question formulation, hypothesis development, experimentation, and conclusion.

Testable Hypothesis

A hypothesis that can be supported or refuted through experimentation.

Formulating a Hypothesis

Generating a testable statement based on observations.

Independent Variables

Factors that are manipulated in an experiment.

Dependent Variables

Factors measured in an experiment in response to changes in the independent variable.