ABS 311 Molecular and Cellular Biology Exam I Review Guide

These flashcards cover key concepts, definitions, and principles from the Molecular and Cellular Biology lecture notes to aid in exam preparation.

Cell Theory

Three postulates that define what a cell is and its role as the basic unit of life.

Microscopy

The use of optical instruments to view small objects, with types including Brightfield, Phase-contrast, Fluorescent, and Electron Microscopy.

Brightfield Microscopy

A type of microscopy that illuminates samples with white light, suitable for observing stained specimens.

Phase-Contrast Microscopy

A microscopy technique that enhances contrast in transparent and colorless objects.

Fluorescent Microscopy

A technique that uses fluorescence to visualize structures within cells.

Transmission Electron Microscopy (TEM)

A microscopy method where electrons are transmitted through a specimen to form an image.

Scanning Electron Microscopy (SEM)

A type of electron microscopy that provides 3D images of the surface of specimens.

Limits of Resolution

The smallest distance between two points that can be distinguished as separate.

Prokaryotic Cells

Simple, unicellular organisms without a nucleus or membrane-bound organelles.

Eukaryotic Cells

Complex cells with a nucleus and membrane-bound organelles.

Ultracentrifugation

A technique using high-speed centrifugation to separate cellular components based on density.

Chromatography

A method for separating components in a mixture based on differential affinities.

Gel-Electrophoresis

A technique for separating DNA, RNA, and proteins based on size and charge.

Hypothesis

A proposed explanation for a phenomenon, serving as a basis for experimentation.

Scientific Method

A systematic approach to inquiry that involves hypothesis formulation, experimentation, and data interpretation.

Carbon-based Life

Life forms on Earth primarily composed of carbon due to its versatile bonding capabilities.

Properties of Carbon

Carbon has four valence electrons, allowing it to form stable covalent bonds with many other elements.

Hydrophilic Molecules

Substances that are attracted to water and can dissolve in it.

Hydrophobic Molecules

Compounds that do not interact well with water and are typically nonpolar.

Covalent Bonds

Strong chemical bonds formed by the sharing of electron pairs between atoms.

Biopolymers

Large molecules made up of repeating smaller units (monomers), including proteins, carbohydrates, and nucleic acids.

Macromolecule

A large molecule formed from smaller organic molecules (monomers) through polymerization.

Amphipathic Molecules

Molecules that have both hydrophilic and hydrophobic parts, essential for forming cell membranes.

Condensation Reaction

A chemical reaction in which two molecules combine to form a larger molecule, with the loss of a small molecule (usually water).

Amino Acids

The building blocks of proteins, characterized by different functional groups that influence protein structure.

Primary Protein Structure

The linear sequence of amino acids in a polypeptide chain.

Peptide Bonds

Covalent bonds that link amino acids together, formed between the carboxyl group of one amino acid and the amino group of another.

Secondary Protein Structure

The local folding of the polypeptide into structures like alpha-helices and beta-sheets, stabilized by hydrogen bonds.

Tertiary Protein Structure

The overall 3D shape of a protein, determined by interactions among various side chains.

Quaternary Protein Structure

The arrangement of multiple polypeptide subunits in a protein.

Disulfide Bond

A strong covalent bond that forms between the sulfur atoms of two cysteine residues in a protein.

Ionic Interactions

Electrostatic attractions between positively and negatively charged side chains of amino acids.

Hydrogen Bonds

Weak attractions between a hydrogen atom attached to an electronegative atom and another electronegative atom.

Dipole-Dipole Interactions

Interactions between polar molecules with permanent dipoles.

London Dispersion Forces

Weak intermolecular forces arising from temporary dipoles generated in molecules.

Globular Proteins

Proteins that are soluble in water and have spherical shapes, typically involved in metabolic processes.

Fiber Proteins

Proteins that provide structural support and are often found in connective tissues.

Nucleic Acids

Biopolymers essential for all known forms of life; includes DNA and RNA.

Nucleotide

The basic structural unit of nucleic acids, composed of a ribose sugar, a phosphate group, and nitrogenous bases.

Directionality in Nucleic Acids

Refers to the orientation of nucleic acid strands from 5' to 3' end.

Phosphodiester Bond

The covalent bond formed between the sugar of one nucleotide and the phosphate of another.

Double Helix

The structure of DNA, consisting of two strands that wind around each other.

Antiparallel Strands

The orientation of the two strands of DNA running in opposite directions.

Hydrogen Bonding in DNA

Specific interactions between nitrogenous bases that stabilize the double helix structure.

Polysaccharides

Carbohydrates made of long chains of monosaccharides, serving various functions in biology.

Glycosidic Bond

A type of covalent bond that joins carbohydrate molecules together through a condensation reaction.

α-1,4 Glycosidic Bond

A linkage found in starch and glycogen, formed between the 1st carbon of one glucose and the 4th carbon of another.

β-1,4 Glycosidic Bond

A linkage found in cellulose, characterized by the β configuration at the 1st carbon.

Cellulose

A polysaccharide that provides structural support in plant cell walls.

Starch

A storage polysaccharide in plants made of α-glucose monomers.

Glycogen

A highly branched storage form of glucose in animals.

Prokaryotic vs Eukaryotic Cells

Prokaryotic cells lack a nucleus and membrane-bound organelles, while eukaryotic cells contain them.

Surface Area-to-Volume Ratio

A measurement that impacts cell size and shape, influencing efficiency of nutrient exchange.

Cell Compartmentalization

Dividing the cell into compartments to enhance efficiency and organization.

Nucleus

The membrane-bound organelle that houses the cell's genetic material.

Mitochondria

Organelles known as the powerhouse of the cell, generating ATP through respiration.

Chloroplasts

Organelles found in plant cells that conduct photosynthesis.

Lysosomes

Membrane-bound organelles that contain digestive enzymes.

Enzymes

Biological catalysts that speed up chemical reactions in the body.

Active Site

The region on an enzyme where substrates bind and undergo a chemical reaction.

Michaelis-Menten Kinetics

A model to describe the rate of enzyme-catalyzed reactions.

Km (Michaelis Constant)

The substrate concentration at which the reaction velocity is half its maximum (Vmax).

Vmax

The maximum rate of an enzyme-mediated reaction when substrate is saturating.

Competitive Inhibition

A type of enzyme inhibition where the inhibitor competes with the substrate for the active site.

Non-competitive Inhibition

Inhibition where the inhibitor binds to a site other than the active site, affecting enzyme activity.

Membrane Fluidity

The viscosity of the lipid bilayer of a cell membrane, affecting movement and function.

Fluid Mosaic Model

A model describing the structure of cell membranes as a mosaic of diverse protein molecules embedded in a fluid lipid bilayer.

Osmosis

The passive movement of water across a semipermeable membrane.

Aquaporin

Channel proteins that facilitate water transport across cell membranes.

Sodium-Potassium Pump

An active transport mechanism that moves sodium out of and potassium into the cell.

Active Transport

The movement of molecules across a cell membrane against their concentration gradient, requiring energy.