Mod 2: Ch 2&3-Molecules of Life/Cell Structures Flashcards
(98 cards)
1
Q
Atomic Number
A
Number of protons in the atomic nucleus; defines the element.
2
Q
Electrons
A
Negatively charged subatomic particle.
3
Q
Element
A
A pure substance that consists only of atoms with the same number of protons.
4
Q
Free Radical
A
Atom with an unpaired electron. Most are highly reactive and can damage biological molecules.
5
Q
Ion
A
An atom or molecule that carries a net charge.
6
Q
Isotopes
A
Forms of an element that differ in the number of neutrons.
7
Q
Mass Number
A
Of an isotope, the total number of protons and neutrons in the atomic nucleus.
8
Q
Neutrons
A
Uncharged subatomic particle that occurs in the atomic nucleus.
9
Q
Nucleus
A
Of an atom; core area occupied by protons and (in most atoms) neutrons. Of a eukaryotic cell; organelle with a double membrane that holds, protects, and controls access to the cell’s DNA.
10
Q
Protons
A
Positively charged subatomic particle that occurs in the nucleus of all atoms.
11
Q
Radioactive Decay
A
Process in which atoms of a radioisotope emit energy and subatomic particles when their nucleus spontaneously breaks up.
12
Q
Radioisotopes
A
An isotopes with an unstable nucleus.
13
Q
Shell Model
A
Conceptual diagram of electron distribution in an atom.
14
Q
Tracers
A
A substance that can be traced via its detectable component.
15
Q
Chemical Bond
A
A strong attractive force between two atoms; links atoms in molecules.
16
Q
Compound
A
Molecules that has atoms of more than one element.
17
Q
Covalent Bond
A
Type of chemical bond in which two atoms share electrons.
18
Q
Ionic Bond
A
Type of chemical bond in which a strong mutual attraction links ions of opposite charge.
19
Q
Polarity
A
Separation of charge into positive and negative regions.
20
Q
Cohesion
A
Property in which the molecules of a substance resist separating from one another.
21
Q
Concentration
A
Amount of solute per unit volume of solution.
22
Q
Evaporation
A
Transition of liquid to a vapor.
23
Q
Hydrogen Bonds
A
Attraction between covalently bonded hydrogen atom and another atom taking apart in a separate covalent bond.
24
Q
Hydrophilic
A
Describes a substance that dissolves easily in water.
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Hydrophobic
Describes a substance that resists dissolving in water.
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Salts
Ionic compound that releases ions other than H+ and OH- when it dissolves in water.
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Solutes
A dissolved substance.
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Solution
Uniform mixture of solute completely dissolved in a solvent.
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Solvent
Liquid in which other substances dissolve.
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Temperature
Measure of molecular motion.
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Acids
Substance that releases hydrogen ions in water.
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Bases
Substance that accepts hydrogen ions in water.
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Buffer
Set of chemicals that can keep pH of a solution stable by alternately donating and accepting ions that contribute to pH.
34
pH
Measure of the amount of hydrogen ions in a fluid.
35
Enzymes
Organic molecule (protein or RNA) that speeds up a reaction without being changed by it.
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Metabolism
Collective term for all of the enzyme-mediated chemical reactions in a cell.
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Monomers
Molecule that is a subunit of polymers.
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Organic
Describes a compound that consists mainly of carbon and hydrogen atoms.
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Polymers
Molecule that consists of multiple monomers.
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Reactions
Process of molecular change.
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Carbohydrates
Saccharide. Molecules that consists primarily of carbon, hydrogen, and oxygen atoms in a ration of approximately 1:2:1. Complex types (poly-saccharides such as cellulose, starch, and glycogen) are polymers of monosaccharides.
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Cellulose
Tough, insoluble polysaccharide that is the major structural material in plants.
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Fat
A triglyceride
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Fatty Acid
Lipid that consists of a (hydrophilic) carboxyl group "head" and a (hydrophobic) "tail".
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Lipid Bilayer
Double layer of phospholipids arranged tail-to-tail; structural foundation of all cell membranes.
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Lipids
Fatty, oily, or waxy organic compound; e.g., a triglyceride, steroid, or wax.
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Phospholipids
Lipid with two (hydrophobic) fatty aid tails and a (hydrophilic) head that contains a phosphate group. Main constituent of eukaryotic cell membranes.
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Saturated Fat
Triglyceride with three saturated fatty acid tails.
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Steroids
A type of lipid with four carbon rings and no fatty acid tails.
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Triglyceride
A lipid with three fatty tails bonded to a glycerol; a fat.
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Unsaturated Fat
Triglyceride molecule with one or more unsaturated fatty acid tails.
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Unsaturated Fatty Acid
Fatty acid that has at least one double bond between carbons making up its tail.
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Waxes
Firm, water-repellent substances that is a complex, varying mixture of lipids.
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Amino Acids
Small organic compound that is a monomer of protein. Consists of a carboxyl group, an amine group, and one of 20 R groups, all bonded to the same carbon atom.
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Denaturation
Loss of protein's three-dimensional shape.
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Peptide Bonds
A covalent bond between the amine group of one amino acid and the carboxyl group of another. Joins amino acids in peptide and polypeptide chains.
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Peptide
Short chains of amino acids.
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Polypeptides
Long chains of amino acids.
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Prion
Infectious protein.
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Protein
Organic molecule that consists of one or more amino acid chains folded into a specific shape.
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ATP
Adenosine triphosphate. Nucleotide that consist of an adenine base, a ribose sugar, and three phosphate group. Nucleotide monomer of RNA and a coenzyme in many reactions. Important energy carrier.
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DNA
Deoxyribonucleic acid. Double-stranded nucleic acid that consists nucleotides. Carries hereditary information.
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Nucleic Acids
Molecule that consists of one or more strands of nucleotides.
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Nucleotides
Small organic modules with a deoxyribose or ribose sugar, or three phosphate groups (e.g. adenin, guianine, cytosine, thymine, and uracil).
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RNA
Ribonucleic acid. Nucleic acid that consists of ribose-containing nucleotides; most types are single-stranded.
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Cell Theory
Theory that all organisms consist of one or more cells; the cell is the basic unit of life; all cells come from division of preexisting cells; and all cells pass hereditary material (DNA) to offspring.
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Cytoplasm
In the eukaryotic cell, collective term for everything between the cell's plasma membrane and its nucleus. In a prokaryotic cell, everything enclosed by the plasma membrane.
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Cytosol
Jellylike mixture of water and solutes enclosed by a cell's plasma membrane.
69
Nucleus
Of an atom; core area occupied by protons and (in most atoms) neutrons. Of a eukaryotic cell; organelle with a double membrane that holds, protects, and controls access to the cell's DNA.
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Organelle
Structure that carries out a specialized functions inside a cell.
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Plasma Membrane
Membrane that encloses a cell and separates it from the external environment.
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Ribosomes
Organelle of protein synthesis. An intact ribosome has two subunits, each composed of rRNA and proteins.
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Surface-to-Volume Ratio
A relationship in which the volume of an object increases with the cube of the diameter, and the surface area increases with the square. Limits cell size.
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Adhesion Proteins
Plasma membrane protein that helps cells stick together in animal tissues. Some types form adhering junctions and tight junctions.
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Cell Wall
Rigid, permeable layer of extracellular matrix that surround the plasma membrane of some cells.
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Flagella
Plural, flagella. Long, slender cellular structure used for movement.
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Fluid Mosaic
Model of a cell membrane as a two-dimensional fluid of mixed composition.
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Pili
Plural, pili. Protein filament that projects from the surface of some prokaryotic cells.
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Receptor Proteins
Membrane protein that triggers a chance in cell activity in response to a stimulus such as a hormone binding to it.
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Transport Proteins
Membrane protein that passively or actively helps specific ions or molecules move across that membrane.
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Biofilm
Community of microorganisms living within a shared mass of secreted slime.
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Chloroplasts
Organelle of photosynthesis in the cells of plants and photosynthetic protists. Outer membranes enclosed stroma and a highly folded thylakoid membrane.
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Endoplasmic Reticulum (ER)
Membrane-enclosed organelle that consists of a continuous system of sacs and tubes extending from the nuclear envelope. Rough ER makes and modifies proteins; smooth ER makes phospholipids, stores calcium, and has additional functions in some cells.
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Golgi Bodies
Organelle that modifies polypeptides and lipids, then sorts and packages the finished products into vesicles. Also called Golgi Apparatus.
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Lysosomes
Enzyme-filled vesicle that breaks down particles such as cellular debris.
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Mitochondria
Double-membraned organelle that produces ATP by aerobic respiration in eukaryotes.
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Nuclear Envelope
A double membrane that constitutes the outer boundary of the nucleus. Nuclear pores in the membrane control the entry and exit of large molecules.
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Vesicles
Saclike organelle that stores, transports, or breaks down its contents.
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Cell Junctions
Molecular assembly that connects a cell to another cell or to extracellular matrix; e.g., tight junction, adhering junction, or gap junction (of animals).
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Cilia
Singular, cilium, Short, hairlike motile structures that project from the plasma membrane of some eukaryotic cells.
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Cuticle
Secreted covering at a body surface. In plants it is waxy and helps conserve water.
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Cytoskeleton
Network of protein filaments that support, organize, and move eukaryotic cells and their internal structures.
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Extracellular Matrix (ECM)
Complex mixture of substances secreted by a cell onto its surface; composition and function vary by cell type.
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Intermediate Filaments
Stable cytoskeleton element that structurally supports cells and tissues of animals and some protists. Different types are assembled from different fibrous proteins.
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Microfilaments
Cytoskeletal element of eukaryotes that reinforces cell membrane and functions in cell movement. Fiber of actin subunits.
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Microtubules
Cytoskeletal element of eukaryotes that dorms a dynamic scaffolding for many cellular processes involving movement. Hollow filament of tubulin subunits.
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Motor Protein
Type of energy-using protein that interacts with cytoskeletal elements to move the cell's parts or the whole cell.
98
Pseudopods
A temporary protrusion from a eukaryotic cell that helps it move or engulf prey.
