Lodish Cellular and Molecular Biology Glossary

Nuclear transport

Movement of macromolecules into or out of the nucleus mediated by nuclear transport receptors

Membrane transport

Movement of molecules across a membrane mediated by a membrane transport protein

CaM-kinase II

Multifunctional Ca2+/calmodulin-dependent protein kinase found in all animal cells that undergoes autohphosphorylation when activated. It is especially abundant in brain and has a role in learning and memory

Beta-catenin

Multifunctional cytoplasmic protein involved in cadherin-mediated-cell-cell adhesion. Links cadherins to the actin cytoskeleton. Also a gene regulatory protein.

Degenerate

Multiple states that amount for the same thing. Different triplet combinations of nucleotide bases (codons) that come for the same amino acid

TOM complex

Multisubunit protein complex that transports proteins across the mitochondrial outer membrane.

Striated muscle

Muscle composed of transversely striped (striated) myofibrils. Skeletal and heart muscle of vertebrates are the best known examples.

Homeotic mutation

Mutation that causes cells in one region of the body to behave as through they were located in another, causing a bizarre disturbance of the body plan

Lethal mutation

Mutation that causes the death of the cell or the organism that contains it

Dominant negative mutation

Mutation that dominantly affects the phenotype by the production of a defective protein or RNA that interferes with the function of the normal gene product in the same cell

Photosystem

Mutliprotein complex involved in photosynthesis that captures the energy of sunlight and converts it to useful forms of energy.

Linkage analysis

Mutual effect of the binding of one ligand on the binding of another that is a central feature of the behavior of all allosteric proteins. Co-inhertiance of two genetic loci that lie near each other on the same chromosome. The closer two loci, the lower the frequency of recombination between them

ER signal sequence

N-terminal signal sequence that directs proteins to enter the ER. It is cleaved off by signal peptidase after entry

Electron

Negatively charged subatomic particle that generally occupies orbitals surrounding the nucleus in an atom

Osmosis

Net movement of water molecules across a semipermeable membrane driven by a difference in concentration of solute on either side. The membrane must be permeable to water but not to the solute molecules

trans Golgi network (TGN)

Network of interconnected cisternae and tubules at the trans face of the Golgi apparatus, through which material is transferred out of the Golgi.

cis Golgi network

Network of interconnected cisternae and tubules which receives vesicles from the endoplasmic reticulum and transfers material to the cis face

Sarcoplasmic reticulum

Network of internal membranes in the cytoplasm of a muscle cell that contains high concentrations of sequestered Ca2+ which is released into the cytosol during muscle excitation.

Cell-cycle control system

Network of regulatory proteins that governs progression of an eukaryotic cell through the cell cycle

Acetylcholine

Neurotransmitter at the vertebrate nervous system. Functions in brain and peripheral nervous system.

Inhibitory neurotransmitter

Neurotransmitter that opens transmitter-gated Cl- or K+ channels in the postsynaptic membrane of a nerve or muscle cell and tends to inhibit action potential generation

Alkaloid

Nitrogen-containing metabolite produced by plants as a defense against herbivores (caffeine, morphine, colchicine)

Innate immune response

Non-specific Immune response to a pathogen that involves the pre-existing defenses of the body such as barriers formed by skin and mucosa, antimicrobial molecules and phagocytes

Intron

Noncoding region of an eukaryotic gene that is transcribed into an RNA molecule but is then excised by RNA splicing during production of a messengerRNA

Hydrogen bond

Nonycovalent bond in which an electropositive hydrogen atom is partially shared by two electronegative atoms

Proto-oncogene

Normal gene, usually concerned with the regulation of cell proliferation, that can be converted into a cancer-promoting oncogene by mutation.

Bright-field microscope

Normal light microscope in which the image is obtained by simple transmission of light through the object

Wild-type

Normal, nonmutant form of an organism; the form found in nature (in the wild)

Adenosine triphosphate (ATP)

Nucleoside triphosphate made of adenine, ribose and three phosphate groups. Principal carrier of energy in cells. The hydrolysis of phosphate groups releases high amounts of energy

Nucleotide

Nucleoside with one or more phosphate groups joined in ester linkages to the sugar. DNA or RNA are polymers of nucleotides

Adenosine diphosphate (ADP)

Nucleotide generated by the hydrolysis of ATP. It can regenerate ATP through oxidative phosphorylation

Cyclic AMP

Nucleotide generated from ATP by adenylyl cyclase in response to simulation of cell-surface receptors. cAMP acts as an intracellular signaling molecule by activating cyclic-amp-depedent kinases. Hydrolyzed to AMP by a phosphodiesterase https://o.quizlet.com/Uyy-4E1CHSWMkuUzrfPMXA_m.png

Promoter

Nucleotide sequence in DNA to which RNA polymerase binds to begin transcription.

Palindromic sequence

Nucleotide sequence that is identical to its complementary strand when each is read in the same chemical direction (e.g. GATC)

Atomic weight

Number of protons and neurons in an atom

Colony stimulating factor

Numerous signal molecules that control differentiation of blood cells

Yolk

Nutritional reserves rich in lipids, proteins and polysaccharides, present in the eggs of many animals.

Chromatid

One copy of a chromosome formed by DNA replication that is still joined at the centromere to the other copy

Inositol phospholipids

One of a family of lipids containing phosphorylated inositol derivates. Important in signal transduction, present in plasma membrane

Histone

One of a group of small abundant proteins rich in arginine and lysine, positively charged that associated with DNA in nucleosomes

MHC molecule

One of a large family of ubiquitous cell-surface glycoproteins encoded by genes of the major histocompatibility complex. They bind peptide fragments of foreign antigens and present them to T cells to induce immune response https://o.quizlet.com/KxCSS7WCy8Rmk97y7oaTYA_m.jpg

Restriction nuclease (restriction enzyme)

One of a large number of nucleases that can cleave a DNA molecule at any site where a specific short sequence of nucleotides occurs. Extensively used in recombinant DNA technology.

Isotope

One of a number of atom forms that differ in atomic weight but have the same number of protons and electrons and therefore have the same chemistry. Can be stable or radioactive

Somite

One of a series of paired blocks of mesoderm that forms during early development and lie on either side of the notochord in a vertebrate embryo. They give rise to the vertebral column, muscles and associated connective tissue. Each somite produces the musculature of one vertebrate segment, plus associated connective tissue.

Follicle cell

One of the cell types that surround a developing oocyte or egg

Blastomere

One of the cells formed by the cleavage of a fertilized egg https://o.quizlet.com/9BEVR4mekntK33oWt5465Q_m.png

Crista

One of the folds on inner mitochondrial membrane. Sensory structure in inner ear https://o.quizlet.com/DjAKAp8gm-e0zsGbiGKYsw_m.png

Light chain

One of the smaller polypeptides of a multisubunit protein such as myosin or immunoglobulin

Pyrimidine

One of the two categories of nitrogen-containing ring compounds found in DNA and RNA. Cytosine, thymine, and uracil are pyrimidines.

Purine

One of the two categories of nitrogen-containing ring compounds found in DNA and RNA. Examples are adenine and guanine.

Bacteria

One of the two major divisions of prokaryotes. Unicellular organisms, some are pathogenic

Leading strand

One of the two newly synthesized strands of DNA found at a replication fork. Made by continuous synthesis in the 5' to 3' direction

Lagging strand

One of the two newly synthesized strands of DNA found on a replication fork. Made in discontinuous lengths that are later joined covalently

Kinesin

One type of motor protein that uses the energy of ATP hydrolysis to move along a microtubule https://o.quizlet.com/e0ufvyyL8GqaZsK4Sq7dOw_m.jpg

Chloroplast

Organelle found in green algae and plants that contains chlorophyll and carries out photosynthesis. Special plastid

Aldehyde

Organic compound that contains a 0=C-H group. Oxidized to an acid or reduced to an alcohol

Amino acid

Organic molecule composed of an amino and a carboxyl group that serves as building blocks of proteins

Ketone

Organic molecule containing a carbonyl group linked to alkyl groups https://o.quizlet.com/y91Sgcgmg1cTpc8I.JfIlQ_m.png

Caged molecule

Organic molecule that is activated by light of a specific wavelength

Lipid

Organic molecule that is insoluble in water but tends to dissolver in non polar organic solvents. Phospholipids form the structural basis of biological membranes

Eukaryote

Organism composed of one or more cells with a distinct nucleus and cytoplasm and membrane-bounded organelles. Includes all forms of life except viruses and prokaryotes

Mutant

Organism in which a mutation has occurred that makes it different from wild type or from the "normal" extent of variation in the population

Temperature-sensitive (ts) mutant

Organism or cell carrying a genetically altered protein (or RNA molecule) that performs normally at one temperature but is abnormal at another (usually higher) temperature.

Lymphoid organ

Organs involved in the production or function of lymphocytes, such as thymus, spleen, lymph nodes, and tonsil

Outer membrane

Outermost of the two membranes surrounding an organelle, the membrane adjacent to the cytosol

Coupled reaction

Pair of chemical reactions in which the free energy released by one of the reactions serves to drive the other

Redox pair

Pair of molecules in which one acts as an electron donor and one as an electron acceptor in an oxidation-reduction reaction; for example, NADH (electron donor) and NAD+ (electron acceptor).

Lampbrush chromosome

Paired chromosome in meiosis in immature amphibian eggs in which the chromatin forms large stiff loops extending out form the linear axis of the chromosome

Antenna complex

Part of a photosystem that captures light E and channels it into the photochemical reaction center. Protein complexes bond to large numbers of chlorophyll molecules and pigments. https://o.quizlet.com/ECYfdv-Sb1RnV8Z350VB.A_m.png

Cell-mediated immune response

Part of an adaptive immune response in which antigen specific T cells are activated to perform various functions such as killing infected cells an activating macrophages

Ribosome

Particle composed of ribosomal RNAs and ribosomal proteins that associates with messenger RNA and catalyzes the synthesis of protein.

Virus

Particle consisting of nucleic acid (RNA or DNA) enclosed in a protein coat and capable of replicating within a host cell and spreading from cell to cell. Many viruses cause disease.

Diffusion

Passive movement of molecules from higher to low concentration regions (along a concentration gradient)

Autoimmune disease

Pathological state in which the body mounts an immune response against one or more of its own potential antigens

Classical pathway

Pathway for activating the complement system that is initiated by IgG or IgM antibodies bound to the surface

Constitutive secretory pathway

Pathway present in all cells by which molecules are continually delivered into the plasma membrane from the Gogli apparatus in vesicles that fuse with the plasma membrane

Diffraction pattern

Pattern set up by wave interference between radiation transmitted or scattered by different parts of an object

Neuropeptide

Peptide secreted by neurons as a signaling molecule either at synapses or elsewhere

S phase

Period of a eukaryotic cell cycle in which DNA is synthesized.

M phase

Period of eukaryotic cycle during which the nucleus and cytoplasm divide

Aqueous

Pertaining to water

Macrophage

Phagocytic cell derived from blood monocytes, typically resident in most tissues. It has both scavenger and antigen presenting functions in immune responses

Prometaphase

Phase of mitosis preceding metaphase in which the nuclear envelope breaks down and chromosomes first attach to the spindle.

Cooperativity

Phenomenon in which the binding of one ligand to a target molecule promotes the binding of successive ligands. Seen in the assembly of large complexes and enzymes and receptors with allosteric subunits https://o.quizlet.com/fwgarCeCgbWOImUhVvRSgA_m.png

Replicative cell senescence

Phenomenon observed in primary cell cultures as they age, in which cell proliferation slows down and finally halts.

Micrograph

Photograph of an image seen through a light or electron microscope

Rod photoreceptor (rod)

Photoreceptor cell type in the retina that is responsible for non-color vision in dim light.

Noncyclic photophosphorylation

Photosynthetic process that produces both ATP and NADPH in plants and cyanobacteria

Cleavage

Physical splitting of a cell into two or a specialized type of cell division seen in early embryos whereby a large cell divides into smaller cells without growth

Microelectrode, micropipette

Piece of fine glass tubing pulled to an even finer tip. Used to penetrate a cell to study its physiology or to inject electric current or molecules

Bacteriorhodopsin

Pigmented protein that pumps protons out of the cell in response to light. Found in plasma membrane of a halobacteria

Transgenic organism

Plant or animal that has stably incorporated one or more genes from another cell or organism and can pass them on to successive generations.

Z disc (Z line)

Plate-like region of a muscle sarcomere to which the plus ends of actin filaments are attached. Seen as a dark transverse line in micrographs.

Checkpoint

Point in the eukaryotic cell division cycle where progress through the cycle can be halted until conditions are suitable for the cell to proceed to the next stage

Alcohol

Polar organic molecule that contains a hydroxyl group bound to a carbon atom other than an aromatic ring

Ribonucleic acid (RNA)

Polymer formed from covalently linked ribonucleotide monomers.

DNA

Polynucleotide formed from covalently linked deoxyribonucleotides units. Serves as the store of hereditary information within a cell and carries it from generation to generation

Insulin

Polypeptide hormone secreted by beta cells in the pancreas that helps regulate glucose metabolism in animals

Glycogen

Polysaccharide composed exclusively of glucose units used to store energy in animal cells. Its large granules are especially abundant in liver and muscle cells

Starch

Polysaccharide composed exclusively of glucose units, used as an energy storage material in plant cells.

Clone

Population of cells/organisms formed by repeated division from a common cell/organism or to produce many copies of a gene by repeated cycles of replication

Immune system

Population of lymphocytes and other white blood cells in the vertebrate body that defends it against infection

Cell line

Population of plant/animal cells capable of dividing indefinitely in culture

Protein domain

Portion of a protein that has a tertiary structure of its own. Larger proteins are generally composed of several domains, each connected to the next by short flexible regions of polypeptide chain.

Locus

Position of a gene on a chromosome. Different alleles of the same gene all occupy the same

Proton

Positively charged subatomic particle that forms part of an atomic nucleus. Hydrogen has a nucleus composed of a single proton (H+).

Protein glycosylation

Post-translational addition of oligosaccharide side chains to a protein.

Malaria

Potentially fatal human disease caused by the protozoan Plasmodium, transmitted by the bite of an infected mosquito

Germ cell

Precursor cell that will give rise to gametes

giga

Prefix denoting 10 to the 9

Milli

Prefix denoting 10^-3

Micro

Prefix denoting 10^-6

mega-

Prefix denoting 10^6

nano

Prefix denoting 10^9

Kilo

Prefix donating 10^3

Class I MHC molecule

Present on almost all cell types and presents viral peptides on the surface of virus-infected cells where they are recognized by T cells

Gene conversion

Process by which DNA sequence information can be transferred from one DNA helix (which remains unchanged) to another whose sequences is altered. The mechanism involves homologous recombination during meiosis and base mismatch repair so that one allele gets converted to another allele

Differentiation

Process by which a cell undergoes a change to an overtly specialized cell type

Chromosome condensation

Process by which a chromosome becomes packed up into a more compact structure previous to M phase of the cell cycle

Exocytosis

Process by which most molecules are secreted from an eukaryotic cell. These molecules are packaged in membrane-bounded vesicles that fuse with the plasma membrane, releasing their contents to the outside https://o.quizlet.com/i/nKuCuNsXZjgJcEp-UxSYVQ_m.jpg

Phagocytosis

Process by which particulate material is endocytosed ("eaten") by a cell. Prominent in carnivorous cells, such as Amoeba proteus, and in vertebrate macrophages and neutrophils.

Carbon fixation

Process by which plants incorporate atmospheric carbon into carbohydrates

Photosynthesis

Process by which plants, algae and some bacteria use the energy of sunlight to drive the synthesis of organic molecules from carbon dioxide and water.

Translation (RNA translation)

Process by which the sequence of nucleotides in a messenger RNA molecule directs the incorporation of amino acids into protein. It occurs on a ribosome.

Oxidative phosphorylation

Process in bacteria and mitochondria in which ATP formation is driven by the transfer of electrons from food molecules to molecular oxygen. Involves the intermediate generation of a pH gradient across a membrane and chemiosmotic coupling

Recombination

Process in which DNA molecules are broken and the fragments are rejoined in new combinations. Can occur in the living cell-for example, through crossing-over during meiosis-or in vitro using purified DNA and enzymes that break and ligate DNA strands.

RNA splicing

Process in which intron sequences are excised from RNA transcripts in the nucleus during formation of messenger and other RNAs.

Cell fusion

Process in which the plasma membranes of two cells fuse down at the point of contact, allowing cytoplasms to mingle

Aerobic

Process that requires or occurs in the presence of O2

Capacitation

Process that sperm must undergo in the female reproductive tract before they are competent for fertilization

Acrosome reaction

Process that takes place when the sperm's head releases hydrolytic enzymes to penetrate the zona pellucida

Constitutive

Produced in constant amount. Opposite of regulated.

immortalization

Production of a cell line capable of an unlimited number of cell divisions. Can be the result of a chemical or viral transformation or of fusion of the original cells with cells of a tumor line

RNA editing

Production of a functional mRNA by insertion or alteration of individual nucleotides in an RNA molecule after it is synthesized.

Parthenogenesis

Production of a new individual from an egg cell in the absence of fertilization by sperm. Component process of apomixis

Alternative RNA splicing

Production of alternative transcripts which will get translated into different proteins by the inclusion or exclusion of exons from a pre-mRNA

Apoptosis

Programmed cell death in which a "suicide" program leads to fragmentation of DNA, shrinkage of the cytoplasm, membrane changes and cell death without lysis or damage to neighboring cells https://o.quizlet.com/3VPZQd5RQsb7g5OubGQavw_m.png

Affinity maturation

Progressive increase in the affinity of antibodies for the immunizing antigen with the passage of time after immunization

Nucleus

Prominent membrane-bounded organelles in a eukaryotic cell, containing DNA organized in chromosomes

Capsid

Protein coat of a virus formed by self-assembly of one or more protein subunits into a geometrical structure

Heterodimer

Protein complex composed of two different polypeptide chains

Gamma-tubulin ring complex

Protein complex containing gamma-tubulin and other proteins that is an efficient nucleator of microtubules https://o.quizlet.com/DHVBONymoRk3BVQrI5sh9g_m.jpg

ARP complex

Protein complex tat nucleates actin filament growth form the (-) end https://o.quizlet.com/EBSpc7vumQF-z.WabrG8fQ_m.png

Cyclin-Cdk complex

Protein complexes that are formed periodically during the eukaryotic cell cycle as the level of cyclin increases, and in which the cyclin dependent kinase (Cdk) becomes partially activated

Pleckstrin homology domain (PH domain)

Protein domain found in intracellular signaling proteins by which they bind to inositol phospholipids phosphorylated by PI 3-kinase.

Actin

Protein found as a monomer G-actin (globular) or as a polymer of F-actin (filamentous) in microfilaments. Essential for mobility and contraction of cells in cell division.

Integral membrane protein

Protein held tightly in a membrane. Can only be removed by treatments that disrupt the lipid bilayer

cyclic AMP-dependent protein kinase

Protein kinase A. Enzyme that phosphorylates target proteins in response to a rise in intracellular cAMP

Cyclin-dependent kinase

Protein kinase that has to be complexed with a cyclin in order to act. By phosphorylating different target proteins they trigger different steps in the cell division cycle

Cdk activating kinase

Protein kinase that phosphorylates and activates Cdks in cyclin-cdk complexes

Ca2+/calmodulin-dependent protein kinase

Protein kinase whose activity is regulated by Ca2+ activated calmodulin and which indirectly mediates the effects of Ca2+ by phosphorylation of other proteins

Cell adhesion molecule

Protein on the surface of an animal cell that mediates cell-cell binding or cell-matrix binding

Antibody

Protein produced by B cells in response to a foreign molecule/cell to which is binds, activating it or marking it for destruction by phagocytosis or complement-induced lysis https://o.quizlet.com/i/KxEGnltl6gcFo8KVO76w5Q_m.jpg

Elongation factor

Protein required for the addition of amino acids to growing polypeptide chains on ribosomes

Signal patch

Protein sorting signal that consists of a specific three-dimensional arrangement of atoms on the folded protein's surface.

Nuclear lamin

Protein subunit of the intermediate filaments of the nuclear lamina

Clathrin

Protein that assembles into a polyhedral cage on the cytosolic side of a membrane, which buds off by endocytosis to form a coated vesicle

Ankryin

Protein that attaches spectrin-actin cytoskeleton to plasma membranes (anchor)

Adaptin

Protein that binds CLATHRIN to the membrane surface in clathrin-coated vesicles https://o.quizlet.com/HA5N6YqHSLsmisobDYgsPQ_m.jpg

Receptor

Protein that binds a specific extracellular signal molecule (ligand) and initiates a response in the cell. Cell-surface receptors, such as the acetylcholine receptor and the insulin receptor, are located in the plasma membrane, with their ligand-binding site exposed to the external medium. Intracellular receptors, such as steroid hormone receptors, bind ligands that diffuse into the cell across the plasma membrane.

Lectin

Protein that binds tightly to a specific sugar. Abundant from plant seeds are often used as assiduity reagents to purify glycoproteins or to deter them on the cell surface

Guanine Nucleotide Exchange Factor

Protein that binds to a GTP-binding protein and activates it by stimulating it to release its tightly bound GDP; thereby allowing it to bind GTP in its place

GTPase-activating protein

Protein that binds to a GTP-binding protein and inactivates it by stimulating its GTPase activity so that it hydrolyzes its bound GTP to GDP https://o.quizlet.com/ZUspvT2BtteoKHxEe-at9w_m.png

Repressor

Protein that binds to a specific region of DNA to prevent transcription of an adjacent gene.

Cdk inhibitor protein

Protein that binds to and inhibits cyclin-Cdk complexes, involved in control of G1 and S phase

Single-strand DNA-binding protein

Protein that binds to the single strands of the opened-up DNA double helix, preventing helical structures from reforming while the DNA is being replicated.

Enzyme

Protein that catalyzed a specific chemical reaction

Allosteric protein

Protein that changes its activity when its conformation is modified

Chaperone

Protein that helps other proteins avoid misfolding, which produces inactive or aggregated polypeptides

Cohesin

Protein that holds together sister chromatids along their length before their separation

Peripheral membrane protein

Protein that is attached to one face of a membrane by noncovalent interactions with other membrane proteins, and which can be removed by relatively gentle treatments that leave the lipid bilayer intact.

Membrane protein

Protein that is normally closely associated with a cell membrane

Scaffold protein

Protein that organizes groups of interacting intracellular signaling proteins into signaling complexes.

Cyclin

Protein that periodically rises and falls in concentration in step with the eukaryotic cell cycle. It activates crucial protein kinases and helps control progression from one stage of the cell cycle to the next

Initiation factor

Protein that promotes the proper association of ribosomes with messenger RNA and is required for the initiation of protein synthesis

ER resident protein

Protein that remains in the ER or its membranes and carried out its function there, as opposed to other that are only in transit

Motor protein

Protein that uses energy derived from nucleoside triphosphate hydrolysis to propel itself along a protein filament or another polymeric molecule

TIM complexes

Protein translocators in the mitochondrial inner membrane. The TIM23 complex mediates the transport of proteins into the matrix and the insertion of some proteins into the inner membrane; the TIM22 complex mediates the insertion of a subgroup of proteins into the inner membrane.

NSF

Protein with ATPase activity that disassembles a complex of a v-SNARE and a t-SNARE

GTP-binding protein

Protein with GTPase activity that binds GTP, which activates the protein. The intrinsic GTPase activity eventually converts the GTP to GDP which inactivates the protein. These GTPases act as molecular switches in intracellular signaling pathways

Mcm proteins

Proteins in the eukaryotic cell that bind to origin recognition complexes in DNA in early G1 and are involved in forming pre-replicative complex https://o.quizlet.com/i5HDxgPcwQBa5uxZn.01eQ_m.png

Adaptor protein

Proteins that link different proteins together in intracellular pathways

Cadherin

Proteins that mediate Ca2+ dependent cell-cell adhesion in animal tissues https://o.quizlet.com/i/KX6rZ9H1QjDCWp3Hn8rThA_m.jpg

Actin-binding protein

Proteins that modifies G- or F-actin's properties (e.g. myosin)

Nernst equation

Quantitative expression that relates the equilibrium ratio of CONCENTRATION of an ION on either side of a permeable membrane to the VOLTAGE difference across the membrane

Antisense RNA

RNA complementary to a specific RNA transcript that hybridizes to it and blocks the RNA's gene function https://o.quizlet.com/jgoPHT2gZhFgm5GEjnDdcA_m.png

Messenger RNA

RNA molecule that specifies the amino acid sequence of a protein. Produced by RNA splicing from a larger RNA molecule in eukaryotes, made by RNA polymerase as a complementary copy of DNA. Translated into a protein in a process catalyzed by ribosomes

Nucleic acid

RNA or DNA, a macromolecule consisting of a chain of nucleotides joined together by phosphodiester bonds

Transcript

RNA product of DNA transcription.

Ribozyme

RNA with catalytic activity.

Retrovirus

RNA-containing virus that replicates in a cell by first making a double-stranded DNA intermediate.

Jak-STAT signaling pathway

Rapid signaling pathway by which some extracellular signals activate gene expression. Involves cell-surface receptor and cytoplasmic Jaks plus signals transducers and activator of transcription (STATs) https://o.quizlet.com/JBuLHmbDYb-BfJqyCx.q1w_m.png

Mutation rate

Rate at which observable changes occur in a DNA sequence

Equilibrium constant (k)

Ratio of forward and reverse rate constant for a reaction and equal to the association constant

Phosphorylation

Reaction in which a phosphate group becomes covalently coupled to another molecule.

Epimerization

Reaction that alters the steric arrangement around one atom, as in a sugar molecule

Autocatalysis

Reaction that is catalyzed by one of its products, creating a positive feedback effect on the reaction rate

V(D)J joining

Recombination process by which gene segments are brought together to form a functional gene for a polypeptide chain of an immunoglobulin or T cell receptor.

General recombination

Recombination that takes place between two homologous chromosomes

FADH2

Reduced flavin adenine dinucleotide. activated carrier molecule that is produced by the citric acid cycle

Supercoiled DNA

Region of DNA in which the double helix is further twisted on itself.

Structural gene

Region of DNA that codes for a protein or for an RNA molecule that forms part of a structure or has an enzymatic function. Distinguished from regions of DNA that regulate gene expression.

Gene

Region of DNA that controls a discrete hereditary characteristic, usually corresponding to a single protein or RNA. It includes coding DNA sequences, non coding regulatory sequences and introns

Nucleolar organizer

Region of a chromosome containing a cluster of ribosomal RNA genes that gives rise to a nucleolus

Heterochromatin

Region of a chromosome that remains highly condensed, transcriptionally inactive during interphase

Active site

Region of an enzyme that interacts with its substrate in order to catalyze a reaction

Variable region

Region of an immunoglobulin light of heavy chain that differs from molecule to molecule; it comprises the antigen-binding site.

Clathrin-coated pit

Region of plasma membrane of animal cells that is coated with clathrin on its cytosolic face. Such regions are continually forming and budding of by endocytosis to form intracellular clathrin-coated vesicles containing extracellular fluid and materials dissolved in it

Smooth endoplasmic reticulum (smooth ER)

Region of the endoplasmic reticulum not associated with ribosomes. It is involved in lipid synthesis.

Binding site

Region on the surface of one molecule that can interact with another molecule through non covalent bonding

Compartment

Regions in the embryo that are formed exclusively from the descendants of a few founder cells. No cell movement between them once these are delimited

Satellite DNA

Regions of highly repetitive DNA from a eukaryotic chromosome, usually identifiable by its unusual nucleotide composition. Satellite DNA is not transcribed and has no known function.

Secondary structure

Regular local folding pattern of a polymeric molecule. In proteins, alpha helices and beta sheets.

Enhancer

Regulatory DNA sequence to which transcription factors bind, influencing the rate of transcription of a gene that can be a thousand of base pairs away (upstream of downstream). It folds in a loop so TFs can interact with a specific promoter

Respiratory control

Regulatory mechanism that controls the rate of electron transport in the respiratory chain according to need via a direct influence of the electrochemical proton gradient.

Antiparallel

Relative orientation of two DNA strands in a double helix. The polarity of one strand is oriented in the opposite direction to that of the other

Stem cell

Relatively undifferentiated cell that can continue dividing indefinitely, throwing off daughter cells that can undergo terminal differentiation into particular cell types.

Signal transduction

Relaying of a signal by conversion from one physical or chemical form to another. In cell biology, the process by which a cell converts an extracellular signal into a response.

Ovulation

Release of an egg from the ovary

Sarcomere

Repeating unit of a myofibril in a muscle cell, composed of an array of overlapping thick (myosin) and thin (actin) filaments between two adjacent Z discs.

Cell cycle

Reproductive cycle of a cell. The orderly sequence of events by which a cell duplicates its contents and divides into two.

Nuclear Magnetic Resonance NMR

Resonant absorption of electromagnetic radiation at a specific frequency by atomic nuclei in a magnetic field, due to flipping of the orientation of their magnetic dipole moment. Provides information about the chemical environment of the nuclei. 2D is used to determine the 3D structure of proteins

Immune response

Response made by the immune system when a foreign substance or microorganism enters its body

Adaptive immune system

Response of immune system to a specific antigen that generates immunological memory

Signal-recognition particle (SRP)

Ribonucleoprotein particle that binds an ER signal sequence on a partially synthesized polypeptide chain and directs the polypeptide and its attached ribosome to the endoplasmic reticulum.

Membrane-bound ribosome

Ribosome attached to the cytosolic face of the endoplasmic reticulum. Site of synthesis of proteins that enter the ER

Free ribosome

Ribosome that is free in the cytosol, unattached to any membrane. It is the site of synthesis of all proteins encoded by the nuclear genome other than those destined to enter the ER. It produces proteins and releases it in the cytosol and used within the cell

Contractile ring

Ring containing actin and myosin that forms under the surface of animal cells undergoing cell division and contracts to pinch the two daughter cells apart https://o.quizlet.com/kDrxZ6ZMZS5iuahcMw94kA_m.png

Lysis

Rupture of a cell's membrane, leading to the release of cytoplasm and the death of the cell

Acrosomal vesicle

Sac of hydrolytic enzymes found in the sperm's head used to digest the egg's coat (ákros, "highest, at the extremity" and sôma, "body")

Genomics

Science of studying DNA sequences and properties of entire genomes

Zygotene

Second stage of division I meiosis, in which the synaptonemal complex begins to form between the two sets of sister chromatids in each bivalent chromosome.

Alpha helix

Secondary protein structure in which a linear sequence of amino acids folds into a right-handed helix stabilized by internal hydrogen bonding

Interleukin

Secreted peptide or protein that mainly mediates local interactions between white blood cells during inflammation and immune responses

Local mediator

Secreted signal molecule that acts at short range on adjacent cells

Immature secretory vesicle

Secretory vesicle that appears to have just pinched off the Golgi stack. Its structure resembles that of a cisterna of the trans Golgi network

Transposable element (Transposon)

Segment of DNA that can move from one position in a genome to another.

Exon

Segment of an eukaryotic gene that consists of a DNA sequence that will be represented in mRNA, tRNA or rRNA after splicing of introns has occurred.

RNA interface (RNAi)

Selective intracellular degradation of RNA that is intended to remove foreign RNAs, such as those of viruses. Fragments cleaved from free double-stranded RNA direct the degradative mechanism to other similar RNA sequences. Widely exploited in a technique used to silence the expression of selected genes.

Cell division

Separation of a cell into two daughter cells. In eukaryotes it entails the division of the nucleus followed by cytokinesis (division of the cytoplasm)

Primary structure

Sequence of monomer units in a linear polymer, such as the amino acid sequence of a protein.

Codon

Sequence of three nucleotides in a DNA or messenger RNA that represents the instruction of incorporation of a specific amino acid into a polypeptide chain during translation

Electron-transport chain

Series of electron carrier molecules that move electrons from a higher to a lower energy level to a final acceptor molecule (e.g. oxygen). The energy released during electron movement can be used to power various processes. In inner mitochondrial membrane and in thylakoid membrane of chloroplasts, generate a proton gradient across the membrane that is used to drive ATP synthesis

Phosphodiester linkage

Set of covalent chemical bonds formed when two hydroxyl groups are linked in ester linkage to the same phosphate group. This linkage joins adjacent nucleotides in RNA or DNA.

Chemical group

Set of covalently linked atoms (-OH, -NH2)

Genetic code

Set of rules specifying the correspondence between nucleotide triplets (codons) in DNA or DNA and amino acids in proteins

Transfer RNA (tRNA)

Set of small RNA molecules used in protein synthesis as an interface (adaptor) between messenger RNA and amino acids. Each type of tRNA molecule is covalently linked to a particular amino acid.

ER retention signal

Short amino acid sequence on a protein that prevents it moving out of the ER, found on ER resident proteins

Start-transfer signal

Short amino acid sequence that enables a polypeptide chain to start being translocated across the endoplasmic reticulum membrane through a protein translocator. Multipass membrane proteins have both N-terminal (signal sequence) and internal start-transfer signals.

Signal sequence

Short continuous sequence of amino acids that determines the eventual location of a protein in the cell. An example is the N-terminal sequence of 20 or so amino acids that directs nascent secretory and transmembrane proteins to the endoplasmic reticulum.

Basal body

Short cylindrical array of microtubules plus their associated proteins found at the base of eukaryotic cell cilia/flagella. Similar to a centriole.

Centriole

Short cylindrical array of microtubules, similar to a basal body. In animal cells, a pair is found at the center of a centrosome.

Okazaki fragments

Short lengths of DNA produced on the lagging strand during DNA replication. Rapidly joined by DNA ligase to form a continuos DNA strand

Oligosaccharide

Short linear or branched chain of covalently linked sugars

Oligomer

Short polymer, in the cell they could consist of amino acids, sugars, or nucleotides (greeks oligos, few)

Operator

Short region of DNA in a bacterial chromosome that controls the transcription of an adjacent gene

RNA primer

Short stretch of RNA synthesized on a DNA template. It is required by DNA polymerase to start their DNA synthesis.

Homeobox

Short, 180 bp long, conserved DNA sequence that encodes a DNA-binding protein motif (homeodomain) famous for its presence in genes involved in orchestrating development in a wide range of organisms

Paracrine signaling

Short-range cell-cell communication via secreted signal molecules that act on adjacent cells

Fission yeast

Shqzosaccharomyces bombe. Unicellular rod-shaped eukaryote used as a model organism in cell and molecular biology (e.g. cell cycle regulation and division)

Terminator

Signal in bacterial DNA that halts transcription.

Plant growth regulator

Signal molecule (also known as a plant hormone) that helps coordinate growth and development. Examples are ethylene, auxins, gibberellins, cytokines, abscisic acid, and the brassinosteroids.

Hormone

Signal molecule secreted by an endocrine cell into the bloodstream, which can carry it to distant target cells

Morphogen

Signal molecule that can impose a pattern on a field of cells by causing cells in different places to adopt different fates

Nuclear localization signal

Signal sequences found in proteins destined for the nucleus and which enable their selective transport into the nucleus from the cytosol through the nuclear pore complexes

Monosaccharide

Simple sugar with the general formula (CH20)n

Prokaryote

Single-celled microorganism whose cells lack a well-defined, membrane-enclosed nucleus. The prokaryotes comprise two of the major domains of living organisms-the Bacteria and Archaea.

X-inactivation center (XIC)

Site in an X chromosome at which inactivation is initiated and spreads outwards.

Regulatory site

Site on an enzyme, other than the active site, that binds a molecule that affects enzyme activity.

Basal

Situated near the base.

Ventral

Situated toward the belly surface of an animal, or towards the underside of a wing or leaf.

Posterior

Situated toward the tail end of the body.

Anterior

Situated towards the head end of the body https://o.quizlet.com/i/J1yYXwLGzooKMD8-KIlWoA_m.jpg

Genomic imprinting

Situation where a gene is either expressed or not expressed in the embryo depending on which parent it is inherited from

Cloning vector

Small DNA molecule usually derived from a bacteriophage or plasmid, which is used to carry a DNA fragment to be cloned into a recipient cell and which allows this to be replicated

Small nuclear RNA (snRNA)

Small RNA molecules that are complexed with proteins to form the ribonucleoprotein particles involved in RNA splicing.

Sugar

Small carbohydrates with a monomer unit of general formula (CH2O)n. Examples are the monosaccharides glucose, fructose, and mannose; and the disaccharide sucrose (composed of a molecule of a molecule of glucose and one of fructose linked together).

Plasmid

Small circular DNA molecule that replicates independently of the genome. Modified plasmids are used extensively as plasmid vectors for DNA cloning.

Activated carrier - Coenzyme

Small diffusible molecule in the cell that stores energy in the form of covalent bonds. ATP, NADPH

Ionophore

Small hydrophobic molecule that dissolves in lipid bilayers and increases their permeability to specific inorganic ions https://o.quizlet.com/5p8fxUOLITALEqugmVcMBg_m.png

Peroxisome

Small membrane-bounded organelle that uses molecular oxygen to oxidize organic molecules. Contains some enzymes that produce and others that degrade hydrogen peroxide (H2O2).

Coated vesicle

Small membrane-bounded organelle with a cage of proteins (coat) on its cytosolic surface. Formed by the pinching off of a coated region or membrane.

Monomer

Small molecular building block that can serve as a subunit, being linked to others of the same type to form a polymer

Coenzyme

Small molecule associated with an enzyme that participates in the reaction catalyzed by the enzyme, often by forming a covalent bond with the substrate

Second messenger

Small molecule that is formed in or released into the cytosol in response to an extracellular signal and helps to relay the signal to the interior of the cell. Examples include cAMP, IP3, and CA2+.

Coenzyme A

Small molecule used in the enzymatic transfer of acetyl groups in the cell

Synaptic vesicle

Small neurotransmitter-filled secretory vesicle formed at the axon terminals of nerve cells and whose contents are released into the synaptic cleft by exocytosis when an action potential reaches the axon terminal.

Glycerol

Small organic molecule that is the parent compound of many small molecules in the cell (e.g. phospholipids) https://o.quizlet.com/i/9MyJ6S-LnCc-YwgN76J80Q_m.jpg

Glutaraldehyde

Small reactive molecule with two aldehyde groups that is often used as a cross-linking fixative https://o.quizlet.com/i/RjNLwAeZ0Q1VfNLTGCRbQA_m.jpg

Lipid raft

Small region of plasma membrane enriched in sphingolipids and cholesterol https://o.quizlet.com/SAkmufpNfTFJZhjVN5FvYg_m.png

Chemokine

Small secreted protein that attracts cells to move towards its source (white blood cells in immune system)

cyclic GMP

Small soluble intracellular signaling molecule formed from GTP by enzyme guanylyl cyclase in response to photoreceptor stimulation in the retina

Microsome

Small vesicle that is derived from fragmented endoplasmic reticulum produced when cells are homogenized

Erythrocyte

Small, hemoglobin containing red blood cell of vertebrates that transports O2 and CO2 to an from tissues

Ubiquitin

Small, highly conserved protein present in all eukaryotic cells that becomes covalently attached to lysines of other proteins. Attachment of a short chain of ubiquitins to such a lysine tags a protein for intracellular proteolytic destruction by a proteasome.

Quinone

Small, lipid soluble, mobile electron carrier molecule found in the respiratory and photosynthetic electron-transport chains.

Vesicle

Small, membrane-bounded, spherical organelle in the cytoplasm of a eukaryotic cell.

Substratum

Solid surface to which a cell adheres.

Nuclear export signal

Sorting signal contained in the structure of molecules and complexes, such as RNA and new ribosomal subunits, that are transported from the nucleus to the cytosol through nuclear pore complexes

Conformation

Spatial arrangement of atoms in three dimensions in a macromolecule

Initiator tRNA

Special tRNA that initiates translation. Always carries the amino acid methionine

Meiosis

Special the o cell division by which eggs and sperm cells are produced. Comprises two successive nuclear divisions with only one round of dan replication, and produces four haploid daughter cells from an initial diploid cell

Hemidesmosome

Specialized anchoring cell junction between an epithelial cell and the underlying basal lamina

Endocrine cell

Specialized animal cell that secretes a hormone into the blood. Usually part of a gland, such as thyroid or pituitary gland

Neuromuscular junction

Specialized chemical synapse between an axon terminal of a motor neuron and a skeletal muscle cell

Cardiac muscle

Specialized form of striated muscle found in the heart, consisting of individual heart muscle cells linked together by cell junctions

Gamete

Specialized haploid cell, either a sperm or an egg, that will fuse for fertilization and thus sexual reproduction to occur

Cell cortex

Specialized layer of cytoplasm on the inner face of plasma membrane. In animal cells it is an actin-rich layer responsible for movement of the cell surface

Cell junction

Specialized region of connection between two cells or between a cell and the extracellular matrix

Cortical granule

Specialized secretory vesicle present under the plasma membrane of unfertilized eggs. It prevents the entry of further sperm after fertilization. https://o.quizlet.com/VV7LFtDqJTtv1LxG3UAEVw_m.png

Spemann's Organizer

Specialized tissue at the dorsal lip of the blastopore in an amphibian embryo; a source of signals that help to orchestrate formation of the embryonic body axis.

Xenopus laevis (South African Clawed Toad)

Species of frog (not toad) frequently used in studies of early vertebrate development.

Drosophila melanogaster

Species of small fly, commonly called a fruit fly, much used in genetic studies of development

Antigenic determinant - Epitope

Specific region of an antigen that binds to an antibody https://o.quizlet.com/2rYoyiYbvfnpPjNYrljwJQ_m.png

Metastasis

Spread of cancer cells from their site of origin to other sites in the body

SH2 domain

Src homology region 2, a protein domain present in many signaling proteins; it binds a short amino acid sequence containing a phosphotyrosine.

Covalent bond

Stable chemical link between two atoms produced by sharing one or more electron pairs

Grana

Stacked membrane discs (thylakoids) in chloroplasts that contain chlorophyll and are the site of the light-trapping reactions of photosynthesis https://o.quizlet.com/i5pyNJIf3Zh8CAiob07xVw_m.jpg

Metaphase

Stage of mitosis at which chromosomes are firmly attached to the mitotic spindle at its equator but have not yet segregated toward opposite poles

Anaphase

Stage of mitosis during which the two sets of chromosomes separate and move away from each other https://o.quizlet.com/ojh0DqDk1nsPLIrYSGF2jQ_m.jpg

Negative staining

Staining technique in electron microscopy in which a reverse, negative, image of the object is created

Dideoxy method

Standard Sanger Sequencing method

Kilojoule

Standard unit of energy equal to 1000 joules

Joule

Standard unit of energy. Energy delivered in one second by one-watt power source. Equal to 0.24 calories

Aster

Star-shaped system of microtubules emanating from a centrosome or from a pole of a mitotic spindle https://o.quizlet.com/HXki0JCU2MnfdkwAXbtACA_m.jpg

Lysogeny

State of a bacterium in which it carries the DNA of an inactive virus integrated into its genome. The virus can subsequently be activated to replicate and lyse the cell

G0

State of withdrawal from the eukaryotic cell division cycle by entry into a quiescent G1 phase. Common state for differentiated cells

Equilibrium

State where there is no net change in a system (e.g. in a chemical reaction when the forward and reverse rates are equal)

Notochord

Stiff rod of mesoderm that runs along the back of all chordate embryos. It does not persist and becomes incorporated into the vertebral column

Bond energy

Strength of the chemical linkage between two atoms measured in kilocalories or kilojoules needed to break it

Heat Shock Protein

Stress-response protein. Protein synthesized in increased amounts in response to an elevated temperature and which usually helps the cell to survive the stress. hsp60, hsp70

Leucine zipper

Structural motif seen in many DNA-binding proteins in which two alpha helices from separate proteins are joined together in a coiled-coil (zipper), forming a protein dimer

Cellulose

Structural polysaccharide consisting of long hairs of covalently linked glucose units. Provides tensile strength in plant cell walls

Beta sheet

Structural protein motif in which different sections of a polypeptide chain run alongside each other joined by hydrogen bonds between atoms in the polypeptide backbone https://o.quizlet.com/TodSHr4iwXygLRAjUcKv4A_m.jpg

Midbody

Structure formed at the end of cleavage that can persist for some time as a tether between the two daughter cells in animals

Phragmoplast

Structure made of microtubules and actin filaments that forms in the prospective plane of division of a plant cell and guides formation of the cell plate.

Transition state

Structure that forms transiently in the course of a chemical reaction and has the highest free energy of any reaction intermediate. Its formation is a rate-limiting step in the reaction.

Synaptonemal complex

Structure that holds paired chromosomes together during prophase I of meiosis and promotes genetic recombination.

Base

Substance that can accept protons in solution. E.g. pyrimidines and purines

Catalyst

Substance that can lower the activation energy of a reaction by increasing its rate

Acid

Substance that donates PROTONS when in water (hydronium ion H3O+)

Antibiotic

Substance toxic to microorganisms

Development

Succession of changes that take place in an organism as a fertilized egg gives rise to an adult

Carbohydrate

Sugars or related compounds containing (CH2O)n

Glial cell

Supporting cell of the nervous system, including oligodendrocytes and astrocytes in the vertebrate central nervous system and Schwann cells in the peripheral nervous system https://o.quizlet.com/jXCbnt7EhS3v6vGWrc1MCg_m.png

Nonsense mediated mRNA decay

Surveillance pathway that exists in all eukaryotes, Its main function is to reduce errors in gene expression by eliminating mRNA transcripts that contain premature stop codons. Translation of these aberrant mRNAs could, in some cases, lead to deleterious gain-of-function or dominant-negative activity of the resulting proteins

Anabolism

System of biosynthetic reactions in a cell by which LARGE molecules are made from SMALLER ones.

Cytoskeleton

System of protein filaments in the cytoplasm of eukayortic cells that gives the cell shape and capacity for directed movement. Made of Actin filaments, microtubules and intermediate filaments https://o.quizlet.com/i/e6uic2G9RYXhymRnI-mICw_m.jpg

Complement system

System of serum proteins activated by antibody-antigen complexes or microorganisms. Helps eliminate pathogens by causing their lysis or promoting phagocytosis

Cytotoxic T cell

T cell responsible for killing infected cells

Adenomatous polyposis coli (APC)

TUMOR SUPRESSOR protein (recruits free cytoplasmic beta catenin and degrades it)

Site-directed mutagenesis

Technique by which a mutation can be made at a particular site in DNA.

Western blotting

Technique by which proteins are separated by electrophoresis and immobilized on a paper sheet and then analyzed, usually by means of a labeled antibody.

Polymerase Chain Reaction

Technique for amplifying a specific region of DNA by the use of sequence specific primers and multiple cycles of DNA synthesis, each cycle being followed by a brief heat treatment to separate complementary strands

Polymerase chain reaction (PCR)

Technique for amplifying specific regions of DNA by the use of sequence-specific primers and multiple cycles of DNA synthesis, each cycle being followed by a brief heat treatment to separate complementary strands.

Phage display

Technique for detecting proteins that interact with each other by screening a protein against a library of genetically modified phage, each displaying a potential binding protein on their surface.

DNA footprinting

Technique for determining the DNA sequence to which a DNA-binding protein binds

X-ray crystallography

Technique for determining the three-dimensional arrangement of atoms in a molecule based on the diffraction pattern of X-rays passing through a crystal of the molecule.

Pulse-chase

Technique for following the movement of a substance through a biochemical or cellular pathway, by briefly adding the radioactively labeled substance (the pulse) followed by the unlabeled substance (the chase).

Two-hybrid system

Technique for identifying interacting proteins using genetically engineered yeast cells.

DNA affinity chromatography

Technique for purifying sequence-specific DNA-binding proteins by their binding to a matrix to which the appropriate DNA fragments are attached

Freeze fracture electron microscopy

Technique for studying membrane structure, in which the membrane of a frozen cell if fractured along the interior of the bilayer separating it into the two monolayers with the interior faces exposed

Southern blotting

Technique in which DNA fragments separated by electrophoresis are immobilized on a paper sheet. Specific fragments are then detected with a labeled nucleic acid probe.

Northern blotting

Technique in which RNA fragments separated by electrophoresis are immobilized on a paper sheet. A specific RNA is then detected by hybridization with a labeled nucleic acid probe

Autoradiography

Technique in which a radioactive object produces an image of itself on a photographic film.

in situ hybridization

Technique in which a single-stranded RNA or DNA probe is used to locate a gene or a messenger RNA molecule to a cell or tissue by hybridization

DNA microarray

Technique than detects the simultaneous expression of a large number of genes in cells, in which isolated cellular mRNAs is hybridized to a large array of short DNA probes immobilized on glass slides

Fluorescent resonance energy transfer (FRET)

Technique used to monitor the distance between two fluorescently labeled molecules (and thus their interaction) in cells

Transcription factor

Term loosely applied to any protein required to initiate or regulate transcription in eukaryotes. Includes both gene regulatory proteins as well as the general transcription factors.

in vitro

Term used to describe a process taking place in an isolated cell-free extract or cells growing in culture as opposed to in an organism (latin for in glass)

Selectivity filter

That part of an ion channel structure that determines which ions it can transport.

Double helix

The 3D structure of DNA in which two DNA chains are held together by hydrogen bonds between the bases and wound into each other

Redox potential

The affinity of a redox pair for electrons, generally measured as the voltage difference between an equimolar mixture of the pair and a standard reference. NADH/NAD+ has a low redox potential and O2/H2 has a high redox potential (high affinity for electrons).

Polypeptide backbone

The chain of repeating carbon and nitrogen atoms, linked by peptide bonds, in a polypetide or protein. The side chains of the amino acids project from this backbone.

Electrochemical gradient

The concentration difference of an ion between the two sides of a membrane and the electrical charge across it (membrane potential), which forces the ion to move across the membrane by a driving force

Combinatorial control

The control of a step in a cellular process by a combination of proteins

Protein phosphorylation

The covalent addition of a phosphate group to a side chain of a protein catalyzed by a protein kinase.

Oocyte

The developing egg. It is usually a large and immobile cell

Vegetal pole

The end at which most of the yolk is located in an animal egg. The end opposite the animal pole.

Plus end

The end of a microtubule or actin filament at which addition of monomers occurs most readily; the "fast-growing" end of a microtubule or actin filament. The plus end of an actin filament is also known as the barbed end.

Minus end

The end of a microtubule or actin filament at which the addition of monomers occurs lead readily; the "slow growing" end of the microtubule or actin filament. Aka pointed end

Post-translational modification

The enzyme-catalyzed change to a protein made after it is synthesized. Examples are acetylation, cleavage, glycosylation, methylation, phosphorylation, and prenylation.

Allelic exclusion

The expression of only one allele while the other allele is silenced (through transcriptional or post transcriptional gene silencing) (Ig)

Heavy chain

The larger of the two types of polypeptides in an immunoglobulin molecule https://o.quizlet.com/Hf6mEulU9-Jjsc3d.Myevw_m.jpg

Germ line

The lineage of germ cells (which contribute to the formation of a new generation of organisms), as distinct from somatic cells (which form the body and leave no descendants)

Membrane

The lipid bilayer plus associated proteins that encloses al cells and in eukaryotic cells, many organelles as well

Phospholipid

The main category of lipid molecules used to construct biological membranes. Generally composed of two fatty acids linked through glycerol phosphate to one of a variety of polar groups.

Protein

The major macromolecular constituent of cells. A linear polymer of amino acids linked together by peptide bonds in a specific sequence.

Hemoglobin

The major protein in red blood cells that associates with O2 in the lungs by means of a bound heme group

Egg

The mature female gamete in sexually reproducing organisms. Usually a large and immobile cell

Sperm

The mature male gamete in animals. It is motile and usually small compound with the egg.

Resting membrane potential

The membrane potential in equilibrium conditions in which there is no net flow of ions across the plasma membrane.

Ras protein

The most famous member of a large family of GTP-binding proteins (called monomeric GTPases) that help relay signals from cell-surface receptors to the nucleus. Named for the ras gene, first identified in viruses that cause rat sarcomas.

Transposition (cut-and-paste transposition)

The movement of a DNA sequence from one site to another within the genome

Nitrogen cycle

The natural circulation of nitrogen between molecular nitrogen in the atmosphere, inorganic molecules in the soil, and organic molecules in living organisms

Ploidy

The number of complete sets of chromosomes in a genome. Diploid organisms have two sets in their somatic cells, polyploid organisms more than two. Natural polyploidy is the result of previous duplications of the whole genome or the introduction of complete genomes from another species during evolution.

Phenotype

The observable character of a cell or organism.

Outer nuclear membrane

The outermost of the two nuclear membranes. Continuous with the ER and is studded with ribosomes on its cytosolic face

Isoelectric point

The pH at which a charged molecule in solution has no net electric charge and therefore does not move in an electric field

Photochemical reaction center

The part of a photosystem that converts light energy into chemical energy.

Side chain

The part of an amino acid that differs between different amino acids, giving the amino acid its unique physical and chemical properties.

Active transport

The pass of a molecule through a membrane channel driven by energy other than the electrochemical gradient of the molecule

Reading frame

The phase in which nucleotides are read in sets of three to encode a protein. A messenger RNA molecule can be read in any one of three reading frames, only one of which will give the required protein.

Synteny

The presence in different species of regions of chromosomes with the same genes in the same order.

Treadmilling

The process by which a polymeric protein filament is maintained at constant length by addition of protein subunits at one end and loss of subunits at the other.

Tumor progression

The process by which an initial mildly disordered cell behavior gradually evolves into a full-blown cancer.

Glycosylation

The process of adding one or more sugars to a protein or lipid molecule

Hybridization

The process whereby two complementary nucleic acid strands form a double helix. Forms the basis of a powerful technique for detecting specific nucleotide sequences

Dynamic instability

The property of sudden conversion from growth to shrinkage or vice versa in a protein filament (e.g. microtubule or actin filament)

Tubulin

The protein subunit of microtubules.

RecA protein

The prototype for a class of DNA-binding proteins that catalyze synapsis of DNA strands during genetic recombination.

Electrochemical proton gradient

The result of a combined pH gradient (proton gradient) and the membrane potential

ER lumen

The space enclosed by the membrane of the endoplasmic reticulum

Gastrulation

The stage in animal embryogenesis during which the embryo is transformed from a ball of cells to a structure with a gut

Metabolism

The total sum of the chemical processes that take place in living cells

Genome

The totality of genetic information belonging to a cell or an organism; in particular the DNA that carries information

Transcytosis

The uptake of material at one face of a cell by endocytosis, its transfer across a cell in vesicles, and its discharge from another face by exocytosis.

Biosphere

The world of living organisms

Entropy

Thermodynamic quantity that measures the degree of disorder in a system (the higher, the greater the disorder)

Lipid bilayer

Thin bimolecular sheet of mainly phospholipid molecules that forms the core structure of all cell membranes. The two layers of lipid molecules are packed with their hydrophobic tails pointing inward and their hydrophilic heads outward, exposed to water

Microvillus

Thin cylindrical membrane-covered projection on the surface of an animal cell containing a core bundle of actin filaments. Present in especially large numbers on the absorptive surface of intestinal epithelial cells https://o.quizlet.com/oUuVYKLcjBtp9J1aqd21yw_m.png

Basal lamina

Thin mat of extracellular matrix that separates epithelial sheets and other types of cells. https://o.quizlet.com/40uUf1LiwG2IV.QveQaIeQ_m.jpg

Filopodium

Thin, spike-like protrusion with an actin filament core, generated on the leading edge of a migrating cell and are involved in chemosensation and locomotion

Quaternary structure

Three-dimensional relationship of the different polypeptide chains in a multisubunit protein or protein complex.

Apical

Tip of a cell, structure or organ. Exposed free surface of an epithelial cell, opposite to the basal surface https://o.quizlet.com/i/YMFzbEQXN0y6-DA5aaGn4A_m.jpg

Avidity

Total binding strength of a polyvalent antibody with a polyvalent antigen

Gene activator protein

Transcription factor. A gene regulatory protein that when bound to its regulatory sequence in DNA, activates transcription

Na+ K+ pump

Transmembrane carrier protein found in the plasma membrane of most animal cells that pumps Na+ out of and K+ into the cell, using energy derived from ATP hydrolysis

Membrane channel

Transmembrane protein complex that allows inorganic ions or other small molecules to diffuse passively across the lipid bilayer

Ion channel

Transmembrane protein complex that forms a water-filled channel across the lipid bilayer through which specific inorganic ions can diffuse down their electrochemical gradients

Integrin

Transmembrane protein involved in the adhesion of cells to the extracellular matrix and to each other

Pump

Transmembrane protein that drives the active transport of ions or small molecules across the lipid bilayer.

Notch

Transmembrane receptor protein involved in many instances of choice of cell fate. Important for cell-cell communication and cell differentiation

Prion disease

Transmissible spongiform encephalopathies such as Kreutzfeld-Jacob disease in humans, scrapie in sheep and bovine spongiform encephalopathy (BSE) in cattle, that are apparently caused and transmitted by abnormal forms of a protein (Prions).

Passive transport

Transport of a solute across a membrane down its concentration or electrochemical gradient using only the energy stored in that gradient

Vesicular transport

Transport of proteins from one cellular compartment to another by means of membrane-bounded intermediaries such as vesicles or organelle fragments.

Transcellular transport

Transport of solutes, such as nutrients, across an epithelium, by means of membrane transport proteins in the apical and basal faces of the epithelial cells.

Anticodon

Triplet of nucleotides in a tRNA molecule that is complementary to a three nucleotide sequence in an mRNA

Neural tube

Tube of ectoderm that will form the brain and spinal cord in a vertebrate embryo

p53

Tumor suppressor gene found mutated in about half of human cancers. It encodes a gene regulatory protein that is activated by DNA damage and is involved in blocking further progression through the cell cycle

Benign

Tumors that are self-limiting in growth and are noninvasive

Complementary

Two nucleic acids that can form a perfect base-paired double helix

Base pair

Two nucleotides in an RNA or DNA molecule held together by hydrogen bonds

Hox complex

Two tightly linked cluster of genes in Drosophila (bithorax and antennapedia complexes) that control the differences between the different segments of the body. Homologous Hox complexes are found in other animals, where they also determine pattern along the anteroposterior axis

van der Waals attraction

Type of (individually weak) noncovalent bond that is formed at close range between nonpolar atoms.

Multidrug resistance protein

Type of ABC transporter protein that can pump hydrophobic drugs, like anti-cancer drugs, out of the cytoplasm of eukaryotic cells

Trans-splicing

Type of RNA splicing present in a few eukaryotic organisms in which exons from two separate RNA molecules are joined together to form an mRNA.

Detergent

Type of amphipathic molecule that tends to coalesce in water, with its hydrophobic tails buried and its hydrophilic heads exposed. It is widely used to solubilize membrane proteins

Desmosome

Type of anchoring cell-cell junction usually formed between two epithelial cells, characterized by dense plaques of protein into which intermediate filaments in the two adjoining cells insert ` https://o.quizlet.com/9kD7IhhcRvTzpAqqobbwyg_m.jpg

Communicating junction

Type of cell junction that allows the passage of chemical/electrical signals from one cell to another

Anchoring junction

Type of cell junction that attaches cells to neighboring cells or extracellular matrix. Desmosons, hemidesmosons and adherent junctions.

Occluding junction

Type of cell junction that seals cells together in an epithelium, forming a barrier through which even small molecules cannot pass

Cytokine receptor

Type of cell surface receptor whose ligands are cytokines (interferons, growth hormone, prolactin) and which acts through the Jak-STAT Pathway https://o.quizlet.com/QuUzAOA46dIGx5EzRNlVnA_m.png

Helper T cell

Type of cell that helps stimulate B cells to make antibodies and activates macrophages to kill ingested microorganisms

Synaptic signaling

Type of cell-cell communication that occurs across chemical synapses in the nervous system.

Affinity chromatography

Type of chromatography that has protein-specific ligands attached to a matrix that allows for purification of a protein mixture

Fibrillar collagen

Type of collagen molecule that assembles into rope-like structures (collagens type I, II, III, V and XI)

Negative control

Type of control of gene expression in which the active DNA-binding form of the regulatory protein turns the gene off

Positive control

Type of control of gene expression in which the active DNA-binding form of the regulatory protein turns the gene on.

M-cyclin

Type of cyclin found in all eukaryotic cells that promotes mitosis

Scanning electron microscope

Type of electron microscope that produces an image of the surface of an object.

Two-dimensional gel electrophoresis

Type of electrophoresis in which the protein mixture is run first in one direction and then in a direction at right angles to the first. It enables better separation of individual proteins.

SDS polyacrylamide gel electrophoresis (SDS-PAGE)

Type of electrophoresis in which the protein mixture to be separated is run through a gel containing the detergent sodium dodecyl sulfate (SDS) which unfolds the proteins and frees them from association with other molecules.

Fluid-phase endocytosis

Type of endocytosis in which small vesicles bud off internally from the plasma membrane carrying extracellular fluid and dissolved molecules into the cell. Pinocytosis https://o.quizlet.com/cLufW8nx9Jac6VP6PMPdvw_m.png

Pinocytosis

Type of endocytosis in which soluble materials are taken up from the environment and incorporated into vesicles for digestion. Literally, "cell drinking."

Oligodendrocyte

Type of glial cell in the vertebrate central nervous system that forms a myelin sheath around axons

Neurofilament

Type of intermediate filament found in nerve cells

Voltage-gated cation channel

Type of ion channel found in the membranes of excitable cells (such as nerve cells and muscle) which opens in response to a shift in membrane potential past a threshold value.

Phase-contrast microscope

Type of light microscope that exploits the interference effects that occur when light passes through material of different refractive indexes. Used to view living cells.

Confocal microscope

Type of light microscope that uses a laser beam as a pinpoint source of illumination and scans across a plane to produce a two-dimensional optical selection

Glycosylphosphatidylinositol anchor

Type of lipid linkage by which some membrane proteins are bound to the membrane. It is formed as the proteins travel through the ER https://o.quizlet.com/8ihTVd6Wek9f6TBtOrkHNw_m.png

Smooth muscle cell

Type of long, spindle-shaped mononucleate muscle cell making up the muscular tissue found in the walls of arteries and of the intestine and other viscera, and in some other locations of the vertebrate body. Called "smooth" because it lacks the striated myofibrils of skeletal and cardiac muscle cells.

T cell (T lymphocyte)

Type of lymphocyte responsible for cell-mediated immunity; includes both cytotoxic T cells and helper T cells.

B cell

Type of lymphocyte that makes antibodies

Feedback inhibition

Type of metabolic regulation in which an enzyme acting early in a reaction pathway is inhibited by a late product of that pathway

Electron microscope

Type of microscope that uses a beam of electrons to create an image

Cut-and-paste transposition

Type of movement of a transposable element in which it is cut out of the DNA and inserted into a new site by a transposase

Translocation

Type of mutation in which a portion of one chromosome is broken off and attached to another.

Inversion

Type of mutation in which a segment of chromosome is inverted

Deletion

Type of mutation in which a single nucleotide or sequence of nucleotides has been removed from DNA

Serine protease

Type of protease that has a reactive serine in the active site.

Site-specific recombination

Type of recombination that does not require extensive similarity in the two DNA sequences undergoing recombination. Can occur between two different DNA molecules or within a single DNA molecule.

Intercalary regeneration

Type of regeneration that fills in the missing tissues when two mismatched parts of a structure and grafted together

Sexual reproduction

Type of reproduction in which the genomes of two individuals are mixed in the formation of a new organism. Individuals produced by sexual reproduction differ from either of their parents and from each other.

Asexual reproduction

Type of reproduction that produces an individual genetically identical to the parent. Does not involve gamete formation and fusion.

Histidine-kinase association receptor

Type of transmembrane receptor found in the plasma membrane of bacteria, yeast and plant cells and involved in sensing stimuli that cause bacterial chemotaxis

DNA-only transposons

Type of transposable element that exists as DNA throughout its life cycle. Many types move by cut-and-paste transposition

Retrotransposon

Type of transposable element that moves by being first transcribed into an RNA copy that is then reconverted to DNA by reverse transcriptase and inserted elsewhere in the chromosomes.

Myoepithelial cell

Type of unstriated muscle cell found in epithelia, e.g. in the iris of the ye and in glandular tissue

Lymphocyte

Type of white blood cell responsible for the specificity of adaptive immune responses. Two main types: B cells (produce antibody) and T cells (interact directly with other effector cells of the immune system and with infected cells). T cells develop in the thymus and are responsible for cell-mediated immunity. B cells develop in bone marrow and are responsible for the production of circulating antibodies

Monocyte

Type of white blood cell that leaves the bloodstream and matures into a macrophage in tissues

Acquired immunological tolerance

UNRESPONSIVENESS of the immune system to a foreign antigen

Anaphase-promoting complex (APC)

Ubiquitin ligase that promotes the destruction of a set of proteins, some of which initiate the separation of star chromatids during Metaphase-to-Anaphase transition during mitosis https://o.quizlet.com/PfndlTFXyo2hMJpxmdBLVQ_m.jpg

Calmodulin

Ubiquitous Ca2+-binding protein whose binding to other proteins is governed by changes in intracellular Ca2+ concentration. Its binding modifies the activity of many target enzymes and membrane transport proteins

Glycolysis

Ubiquitous metabolic pathway in the cytosol in which sugars are incompletely degraded with production of ATP

Neutron

Uncharged subatomic particle that forms part of an atomic nucleus

Mannose 6-phosphate

Unique marker attached to oligosaccharides on some glycoproteins destined for lysosomes

Kilocalorie

Unit of heat energy equal to 1000 calories. Used to express the energy content of food or molecules

Calorie

Unit of heat. Amount of heat needed to raise the temperature of 1 g of water by 1 C

Nanometer

Unit of length commonly used to measure molecules and cell rganeless. 10^-9 m

Angstrom

Unit of length used to measure atoms/molecules. 10-10 meter

Dalton

Unit of molecular mass. Aprox. equal to the mass of a hydrogen atom (1.66 x 10 -24 g)

Endocytosis

Uptake of material into a cell by an invagination of the plasma membrane and its internalization in a membrane-bounded vesicle

Immunoprecipitation

Use of a specific antibody to draw its corresponding protein antigen out of a solution

Single-nucleotide polymorphism (SNP)

Variation between individuals at certain nucleotide positions in the genome.

Vacuole

Very large fluid-filled vesicle found in most plant and fungal cells, typically occupying more than a third of the cell volume.

Nonenveloped virus

Virus consisting of a nucleic acid core and protein capsid only

Lamba bacteriophage

Virus that infects E. coli. Widely used as a DNA cloning vector

Enveloped virus

Virus with a capsid surrounded by a lipid membrane, which is derived from the host cell plasma membrane when the virus buds from the cell https://o.quizlet.com/pLwKgs9xcoc.d3dmySKO.g_m.png

Membrane potential

Voltage difference across a membrane due to a slight excess of positive ions on one side and of negative ions on the other (typically -60 mV)

Phospholipid exchange protein

Water-soluble carrier protein that transfers a phospholipid molecule from one membrane to another.

Amino group

Weakly basic functional group derived from ammonia in which one or more H atoms are replaced by another atom.

Determined

When an embryonic cell has committed to a particular specialized path of development which reflects a change in the internal character of the cell preceding cell differentiation

Leucocyte

White blood cell

Neutrophil

White blood cell that is specialized for the uptake of particular material by phagocytosis and which enters tissues that become infected of inflamed

Alga

Wide range of simple unicellular and multicellular photosynthetic eukaryotes

Mole

X grams of a substance, where X is its relative molecular mass. It consists of 6 x 10^23 molecules of substance

Chiasma

X-shaped connection visible between paired homologous chromosomes during synapsis in meiosis. Represents a site of crossing over

Holliday junction

X-shaped structure observed in DNA undergoing recombination, in which the two DNA molecules are held together at the site of crossing-over

Replication fork

Y-shaped region of a replicating DNA molecule at which the two daughter strands are formed and separate.

Hydrocarbon

compound that has only carbon and hydrogen atoms

Focal adhesion

focal contact/adhesion plaque. Type of anchoring cell junction, forming a small region on the surface of a fibroblast or other cell that is anchored to the extracellular matrix. Attachment is mediated by transmembrane proteins which are linked through other proteins to actin filaments in the cytoplasm

Homolog

one of two or more genes that are similar in sequence as a result of derivation from the same ancestral gene. The term covers both orthologs and paralogs

Intracellular signaling protein

protein tha relays a signal as part of an intracellular signaling pathway. It may either activate the next protein in the pathway or generate a small intracellular mediator

Intermembrane space

subcompartment formed between inner and outer mitochondrial membranes or chloroplasts

Endocytic exocytic cycle

the processes of endocytosis and exocytosis that add and remove plasma membrane from the cell respectively, resulting in no overall change in the cells surface area and volume

Hydroxyl

(-OH). Chemical group consisting of a hydrogen atom linked to an oxygen

Synapsis

(1) In genetic recombination, the initial formation of base pairs between complementary DNA strands in different DNA molecules that occurs at sites of crossing-over between chromosomes. (2) In meiosis, the pairing of maternal and paternal copies of a chromosome as they become attached to each other along their length.

Stroma

(1) The connective tissue in which a glandular or other epithelium is embedded. (2) The large interior space of a chloroplast, containing enzymes that incorporate CO2 into sugars.

Free energy

(G). Energy that can be extracted from a system to drive reactions. Takes into account changes in both energy and entropy

Leptotene

1st phase of division I of meiosis, in which the paired duplicated homologous chromosomes condense and become visible in the light microscope

Cytochrome b-c1 complex

2nd of the 3 electron-driven proton pumps in respiratory chain. It accepts electrons from ubiquinone

Cytochrome oxidase complex

3rd of the 3 electron-driven proton pumps in respiratory chain. It accepts electrons from cytochrome c and generates H2O using O2 as an electron acceptor https://o.quizlet.com/ftcfAhVZ6ncMO-X43dzucA_m.png

Pachytene

3rd stage of division I of meiosis, in which synapsis is complete

Avogadro's number

6 x 10 23 Numer of atoms in 1 gram of H.

Glucose

6-carbon sugar that plays a major role n the metabolism of living cells. Stored in polymeric form as glycogen in animal cells and as starch in plant cells

K+ leak channel

A K+ transporting ion channel in the plasma membrane of animal cells that remains open even in a resting cell

Type III secretion system

A bacterial system for delivering toxic proteins into the cells of their host.

Induction

A change in the developmental fate of one tissue caused by an interaction with another tissue

Metaplasia

A change in the pattern of cell differentiation in a tissue

Class switching

A change that many B cells undergo during immune response from making one class of immunoglobulin to making another

Autosome

A chromosome other than a sex chromosome

Homologous chromosome

A chromosome that has same similar genetic sequence, the same genes in the same loci, size and centromere placement. Each copy being derived from a different parent

Primosome

A complex of DNA primase and DNA helicase that is formed on the lagging strand during DNA replication, improving the efficiency of replication.

Phosphatidylinositol 3-kinase (PI 3-kinase)

A kinase involved in intracellular signaling pathways activated by a variety of cell-surface receptors. It phosphorylates inositol phospholipids at the 3 position of the inositol ring.

Stereocilium

A large, rigid microvillus found in "organ pipe" arrays on the apical surface of hair cells in the ear. It contains a bundle of actin filaments, rather than microtubules, and is thus not a true cilium.

Protofilament

A linear chain of protein subunits joined end to end, which associates laterally with other protofilaments to form cytoskeletal components such as microtubules and intermediate filaments.

Kinetochore microtubule

A microtubule in a mitotic or meiotic spindle that remains attached to the kinetochore on a chromosome

Conditional mutation

A mutation that changes a protein or RNA molecule so that its function is altered only under some conditions (e.g. temperature-sensitive mutations)

Redox reaction

A reaction in which one component becomes oxidized and the other reduced; and oxidation-reduction reaction.

Genetic screen

A search through a large collection of mutations for a mutant with a particular phenotype

Template

A single strand of DNA or RNA whose nucleotide sequence acts as a guide for the synthesis of a complementary strand.

Model organism

A species that has been studies intensively over a long period and serves as a "model" of the biology of a particular type of organism

Section

A very thin slice of tissue, suitable for viewing under the microscope.

Expression vectors

A virus or plasmid that carries a DNA sequence into a suitable host cell and directs the protein synthesis encoded by the sequence

Bacteriophage

A virus that infects bacteria. Widely used as cloning vectors

Spectrin

Abundant protein associated with the cytosolic side of the plasma membrane in red blood cells, forming a rigid network that supports the membrane.

Acetyl CoA

Acetyl + CoA through a tioester group. Water-soluble molecule that carries acetyl groups in cells.

Nicotine adenine dinucleotide phosphate NADP+

Activated carrier closely related to NAD+ that is used extensively in biosynthetic, rather than catabolic, pathways. Reduced form is NADPH

Nicotine adenine dinucleotide NAD+

Activated carrier that participates in an oxidation reaction by accepting a hydride ion (H-) from a donor molecule. The NADH formed is an important carrier of electrons for oxidative phosphorylation

Aminoacyl tRNA

Activated tRNA used in protein synthesis that contains an amino acid linked from its carboxyl group to a hydroxyl group on tRNA.

Secondary immune response

Adaptive immune response to an antigen that is made on a second or subsequent encounter with a given antigen. It is more rapid in onset, stronger, and more specific than the primary immune response.

Primary immune response

Adaptive immune response to an antigen that is made on first encounter with that antigen.

O-linked glycosylation

Addition of an oligosaccharide chain to a protein through the OH group of a serine or threonine side chain

Reduction

Addition of electrons to an atom, as occurs during the addition of hydrogen to a molecule or the removal of oxygen from it. Opposite of oxidation.

DNA methylation

Addition of methyl groups to DNA. Extensive addition of these groups in the cytosine base of CG sequences keeps genes in an inactive state in eukaryotes. In prokaryotes, cytosines and adenines can be marked this way to protect their native DNA (primitive immune system against bacteriophages)

DNA supercoiling

Additional twisting of the DNA helix that occurs in response to the superhelical tension created when, for example, a circular DNA is partly unwound

Adaptation

Adjustment of sensitivity followed by repeated stimulation

Allele

Alternative forms of a gene that occupy the same position on homologous chromosomes

Sorting signal

Amino acid sequence that directs the delivery of a protein to a specific location outside the cytosol.

Oncogene

An altered gene whose product can act in a dominant fashion to help make a cell cancerous. Typically a mutant form of a normal gene (porto-oncogene) involves in the control of cell growth or division

Immunoglobulin

An antibody molecule. Higher vertebrates have five classes of immunoglobulin (A, D, E, G and M) each with different role in the immune response

Ion

An atom that has either gained or lost electrons to acquire a charge

Mitogen

An extracellular substance, such as a growth factor, that stimulates cell proliferation

Prion

An infectious abnormal form of a normal protein that is replicated in the host by forcing the normal proteins of the same type to adopt the aberrant structure.

Phosphatidylinositol

An inositol phospholipid.

Mosaic

An organism made of a mixture of cells with different genotypes

Pathogen

An organism or other agent that causes disease.

Meristem

An organized group of dividing cells whose derivatives give rise to the tissue and organs of a flowing plant. Key examples are apical meristems at the tips of shoots and roots

Fermentation

Anaerobic energy-yielding metabolic pathway that produces acids, gases or alcohol from sugars in the absence of oxygen

Autoantibody

Antibody produced by an organism against an antigen of its own cells and tissues

Monoclonal antibody

Antibody secreted by a hybridoma clone. Each such clone is derived from a single B cell, all of the antibody molecules produced are identical

Recombinant DNA

Any DNA molecule formed by joining DNA segments from different sources. Recombinant DNAs are widely used in the cloning of genes, in the genetic modification of organisms, and in molecular biology generally.

Carcinogen

Any agent that causes cancer (e.g. chemical or radiation)

Somatic cell

Any cell of a plant or animal other than a germ cell or germ cell precursor.

Post-transcriptional control

Any control on gene expression that is exerted at a stage after transcription has begun.

Ganglioside

Any glycolipid having one or more sialic acid residues in its structure. Found in the plasma membrane of eukaryotic cells and especially abundant in nerve cells https://o.quizlet.com/BlZqTbGlp9TZBGjMFBjRwA_m.jpg

Ligand

Any molecule that binds to a specific site on a protein or other molecule (latin ligare)

Solute

Any molecule that is dissolved in a liquid. This liquid is called a solvent.

Rab protein

Any of a large family of monomeric GTPases present in the plasma membrane and organelle membranes that are involved in conferring specificity on vesicle docking.

Nucleoporin

Any of a number of different proteins that make up nuclear pore complexes

Respiratory enzyme complex

Any of the major protein complexes of the mitochondrial respiratory chain that act as electron-driven proton pumps to generate the proton gradient across the inner membrane.

Astral microtubule

Any of the microtubules in a mitotic spindle emanating from the aster that are not attached to a chromosome's kinetochore https://o.quizlet.com/dywcGZp4ImDUZ8Wb.BuIIg_m.jpg

Hypervariable region

Any of three small regions within the variable region of an immunoglobulin light chain or heavy chain that show the highest variability from molecule to molecule. These regions determine the specificity of the antigen-binding site

Ubiquitin ligase

Any one of a large number of enzymes that attach ubiquitin to a protein, thus marking it for destruction in a proteasome. The process catalyzed by a ubiquitin ligase is called ubiquitylation.

Ribosomal RNA

Any one of a number of specific RNA molecules that form part of the structure of a ribosome and participate in the synthesis of proteins. Often distinguished by their sedimentation coefficient, such as 28S rRNA or 5S rRNA.

Gene regulatory protein

Any protein that binds to a specific DNA sequence to alter gene expression

General transcription factor

Any protein whose assembly around the TATA box is required for the initiation of transcription of most eukaryotic genes

Globular protein

Any protein with an approximately rounded shape. Such proteins are contrasted with highly elongated, fibrous proteins such as collagen

Glycoprotein

Any protein with one or more oligosaccharide chains covalently linked to amino acid side chains. Most secreted or exposed (on the outer surface of plasma membrane) proteins

Connective tissue

Any supporting tissue that lies between other tissues and consists of cells embedded in an extracellular matrix (e.g. bone, cartilage)

Myeloid cell

Any white blood cell other than lymphocytes

Reverse genetics

Approach to discovering gene function that starts from the DNA (gene) and protein and then creates mutants to analyze the gene's function.

Benzene

Aromatic molecule composed of a six-membered carbon ring. Contains three alternative double bonds. https://o.quizlet.com/mZ1QIdB-TRVzIcs3dvpGYg_m.png

Mitotic spindle

Array of microtubules and associated molecules that forms between the opposite poles of a eukaryotic cell during mitosis and serves to move the duplicated chromosomes apart

Liposome

Artificial phospholipid bilayer vesicle formed from an aqueous suspension of phospholipid molecules https://o.quizlet.com/w0JCUjLutMS-JjgseF4oPA_m.jpg

Black membrane

Artificial planar lipid bilayer membrane

Complex

Assembly of molecules that are held together by non covalent bonds

Electron acceptor

Atom or molecule that takes up electrons readily, thereby gaining an electron and becoming reduced (e.g. oxygen, nitrate, iron)

Consensus sequence

Average of most typical form of a sequence that is reproduced with minor variations in a group of related DNA, RNA or protein sequences. It shows the nucleotide or amino acid most commonly found at each position. The preservation of it implies that it is functionally important

Anteroposterior

Axis running from head to tail https://o.quizlet.com/Bos6Imd5Nvaqox4bZyLmRQ_m.png

Dorsal

Back of an animal. Upper surface of a leaf or wing

Budding yeast

Baker's yeast or Saccharomyces cerevisiae

Gray crescent

Band of pale pigmentation that appears in the egg of some species of amphibians, opposite the site of sperm entry following fertilization. Caused by rotation of the egg cortex and associated pigment granules. Marks the future dorsal side https://o.quizlet.com/i/eVlvZLj8PQE4i4yQLDYZbg_m.jpg

Nucleosome

Beadlike structure in eukaryotic chromatin composed of a short length (146 bp) of DNA wrapped around a core of histone proteins, fundamental structural unit of chromatin

Adhesion belt - Zonula adherens

Beltlike adherens junction belt that encircles the apical end of an epithelial cell and attaches it to the adjoining cell. https://o.quizlet.com/i/e9iDNTeT8DdHITy4rzyHGg_m.jpg

Nitrogen fixation

Biochemical process carried out by certain bacteria that reduces atmospheric nitrogen to ammonia, leading eventually to various nitrogen containing metabolites

Chromatography

Biochemical technique in which a mixture of substances is separated by charge, size, or some other property allowing it to partition in moving phase and stationary phase

Blotting

Biochemical technique in which macromolecules are separated on an agarose/polyacrylamide gel and transferred to a nylon membrane/sheet of paper for their immobilization https://o.quizlet.com/79X2Sf-i8VEDrET6AJNWWw_m.png

Axoneme

Bundle of microtubules and associated proteins that forms the core of a cilium or flagellum in an eukaryotic cell and is responsible for their movement https://o.quizlet.com/zE-xO9qOCWu7VpkYDks2kw_m.png

Acetyl

CH3-C=O Functional group derived from acetic acid. Added to some proteins as post translational modification.

Calcium pump

Ca2+ ATPase. Transport protein in the sarcoplasmic reticulum membrane that pumps Ca2+ out of the cytoplasm into the sarcoplasmic reticulum using ATP https://o.quizlet.com/W9zBV7bHlzUnlhlpH7ab1g_m.jpg

Protein kinase C (PKC)

Ca2+-dependent protein kinase that, when activated by diacylglycerol and an increase in the concentration of Ca2+, phosphorylates target proteins on specific serine and threonine residues.

Sarcoma

Cancer of connective tissue.

Carcinoma

Cancer of epithelial cells. Most common form of human cancer

Leukemia

Cancer of white blood cells

Disaccharide

Carbohydrate molecule consisting of two covalently joined monosaccharide units

Carboxyl group

Carbon atom linked to a oxygen atom by a double bond and to hydroxyl group. Weak acids https://o.quizlet.com/i/RcoBzTimI5rAKpGhNIzHZQ_m.jpg

Carbonyl group

Carbon atom linked to a oxygen atom by a double bond https://o.quizlet.com/iAVSuovpDb-iQy..vjL9BA_m.jpg

Colorectal tumor

Carcinoma of the epithelium linen of the colon and rectum

Uniporter

Carrier protein that transports a single solute from one side of the membrane to the other.

Antiporter

Carrier protein that transports two different ions or small molecules across a membrane in opposite direction, simultaneously or in sequence https://o.quizlet.com/sAmsLikWYszq-tlP13wWig_m.png

Symporter

Carrier protein that transports two types of solute across the membrane in the same direction.

Chondrocyte

Cartilage cell. Connective tissue cell that secretes the matrix of cartilage

Granulocyte

Category of white blood cell distinguished by conspicuous cytoplasmic granules https://o.quizlet.com/fVGEs1IE51nq0Hz2DELsJA_m.png

Lumen

Cavity enclosed by an epithelial sheet or by a membrane

Neural cell adhesion molecule N-CAM

Cell adhesion molecule of the immunoglobulin superfamily, expressed by many cell types including most nerve cells. Mediates Ca2+ independent cell-cell attachement in vertebrates

Glycocalyx

Cell coat. Carbohydrate-rich layer that forms the outer coat of an eukaryotic cell. Composed of oligosaccharides linked to intrinsic plasma membrane glycoproteins and glycolipids, as well as glycoproteins and proteoglycans that have been secreted and reabsorbed onto the cell surface https://o.quizlet.com/i/gX78Sst4XZjr_zHuVEfEMQ_m.jpg

Nurse cell

Cell connected by cytoplasmic bridges to a developing oocyte and which thereby supplies it with ribosomes, mRNAs, and proteins needed for the development of the early embryo

Dendritic cell

Cell derived from bone marrow and present in lymphoid and other tissues that is specialized for the uptake of particulate material by phagocytosis and which acts as a professional antigen-presenting cell in immune responses

Embryonic stem cell (ES cell)

Cell derived from the inner cell mass of the early mammalian embryo that can give rise to all the cells in the body. It can be grown in culture, genetically modified and inserted into a blastocyst to develop a transgenic animal

Asymmetric cell division

Cell division that produces two daughter cells that differ in size or in absence or presence of cytoplasmic constituent

Platelet

Cell fragment, lacking a nucleus, that breaks off from a megakaryocyte in the bone marrow and is found in large numbers in the bloodstream. It helps initiate blood clotting when blood vessels are injured.

Adherens junction

Cell junction in which the cytoplasmic face of the plasma membrane is attached to actin filaments https://o.quizlet.com/i/_0_IrBN31y_OWDfZwCwx5Q_m.jpg

Hybridoma

Cell line used in the production of monoclonal antibodies

Photoreceptor

Cell or molecule that is sensitive to light.

Primordial germ cell

Cell set aside early in embryonic development that is a precursor to germ cells that give rise to gametes.

Autocrine signaling

Cell signaling in which a cell recreates signal molecules that act on itself or adjacent cells of the same type

Effector cell

Cell that carried out the final response or function of a particular process. (e.g. lymphocytes and phagocytes destroy pathogens and remove them from the body)

Antigen-presenting cell

Cell that displays foreign antigens complexed with MHC (major histocompatibility complex) molecules on its surface

Melanocyte

Cell that produces the dark pigment melanin. Responsible for pigmentation of skin and hair

Osteoblast

Cell that secretes matrix of bone

Chromaffin cell

Cell that stores adrenaline in secretory vesicles and secretes it in times of stress when stimulated by the nervous system

Neuron

Cell with long processes specialized to receive, conduct and transmit signals in the nervous system

Heterocaryon

Cell with two or more genetically different nuclei; produced by the fusion of two or more different cells

Anaerobic

Cell, organism or process that functions in the absence of O2

Contact-dependent signaling

Cell-cell communication in which the signal molecule remains bounds https://o.quizlet.com/zbLNfOaVs6pW2a8Jhm240g_m.jpg

Tight junction

Cell-cell junction that seals adjacent epithelial cells together, preventing the passage of most dissolved molecules from one side of the epithelial sheet to the other.

CD28

Cell-surface protein on T cells that binds the B7 protein on antigen-presenting cells providing an additional signal required for the activation of a naive T cell by an antigen

G-protein linked receptor

Cell-surface receptor that associates with an intracellular trimeric GTP-binding protein after receptor activation by an extracellular ligand. Seven-pass transmembrane proteins

Convergent extension

Cellular rearrangement within a tissue that causes it to extend in one dimension and shrink in another https://o.quizlet.com/lld1wc2IlfwEKgF0w7ykFQ_m.png

Unfolded protein response

Cellular response triggered by an accumulation of misfolded proteins in the endoplasmic reticulum. It involves increased transcription of ER chaperones and degradative enzymes.

Matrix space

Central subcompartment of a mitochondrion, bounded by the inner mitochondrial membrane. The corresponding compartment in a chloroplast, which is more commonly known as stroma

Centrosome

Centrally located organelle of animal cells that is the microtubule organizing center and acts as the spindle pole during mitosis. Consists of a pair of centrioles

Complex oligosaccharide

Chain of sugars attached to a glycoprotein

High-mannose oligosaccharide

Chain of sugars attached to a glycoprotein which contains many mannose residues

N-linked oligosaccharide

Chain of sugars attached to a protein through the NH2 group of the side chain of an asparagine residue

Dysplasia

Change in cell growth and behavior in a tissue in which the structure becomes disordered

Denaturation

Change in conformation of a protein or nucleic acid caused by heat or exposure to chemicals that results in loss of biological function

Free energy change

Change in the free energy during a reaction:

Point mutation

Change of a single nucleotide in DNA, especially in a region of DNA coding for protein.

Immunoglobulin domain

Characteristic protein domain of about 100 amino acids found in immunoglobulin light and heavy chains. Similar domains, immunoglobulin-like domains are present in many other proteins involved in cell-cell interactions and antigen recognition and define the Ig superfamily

Peptide map

Characteristic two-dimensional pattern (on paper or gel) formed by the separation of the mixture of peptides produced by the partial digestion of a protein.

Spindle-attachment checkpoint

Checkpoint that operates during mitosis to ensure that all chromosomes are properly attached to the spindle before sister-chromatid separation starts.

Peptide bond

Chemical bond between the carbonyl group of one amino acid and the amino group of a second amino acid-a special form of amide linkage. Peptide bonds link amino acids together in proteins.

Noncovalent attraction

Chemical bond in which no electrons are shared. They are relatively weak, but can sum together to produce strong, highly specific interactions between molecules. Some examples are hydrogen bonding, Van der Waals forces, etc

Label

Chemical group (radioactive atom or fluorescent dye) added to a molecule in order to follow its progress in a biochemical reaction or to locate it spatially

Sulfhydryl (thiol, -SH)

Chemical group containing sulfur and hydrogen found in the amino acid cysteine and other molecules. Two sulfhydryls can join to produce a disulfide bond.

Neurotransmitter

Chemical messengers, small signal molecule that transmit a signal across a chemical synapse from one neuron to another target neuron, e.g. acetylcholine, glutamate, GABA, glycine

Condensation reaction

Chemical reaction in which two molecules are covalently linked through -OH groups with the removal of H2O

Fixative

Chemical reagent such as formaldehyde or osmium tetroxide used to preserve cells for microscopy. Samples created with these samples are said to be "fixed" and the process is called "fixation"

Genomic DNA

Chromosomal DNA constituting the genome of a cell or an organism inherited from generation to generation

Sex chromosome

Chromosome that may be present or absent, or present in a variable number of copies, according to the sex of the individual. In mammals, the X and Y chromosomes.

Preprophase band

Circumferential band of microtubules and actin filaments that forms around a plant cell under the plasma membrane prior to mitosis and cell division.

Gq

Class of receptor-coupled G protein that activates phospholipase C-beta and originates the inositol phospholipid signaling https://o.quizlet.com/nVTkQXGEOkV5WcUUQhAlgA_m.png

Hydrolysis

Cleavage of a covalent bond with accompanying addition of water, -H added to one product of the cleavage and -OH to the other https://o.quizlet.com/TxAIQ6l7jyvYIZI8DoOuzg_m.png

Bacterial artificial chromosome (BAC)

Cloning vector that can accommodate large pieces of DNA (1 million bp)

Ganglion

Cluster of nerve cells and associated glial cells located outside the central nervous system

CD8

Co-receptor protein found on cytotoxic T cells that binds to class I MHC molecules outside the antigen-binding site https://o.quizlet.com/AcgtttzSY1EkEUXfQ8binQ_m.jpg

CD4

Co-receptor protein found on helper T-cells that binds to class II MHC molecules outside the antigen-binding site

Epithelium

Coherent cell sheet formed from one or more layers of cells covering an external surface or lining a cavity

Ionic bond

Cohesion between two atoms, one with a positive charge and other with a negative charge. One type of non covalent bond

DNA library

Collection of cloned DNA molecules, representing the entire genome (genomic library) or the DNA copies of the messenger RNA produced by a cell (cDNA library)

Cytochrome

Colored, heme (Fe2+)-containing protein that transfers electrons during cellular respiration and photosynthesis

Lymph

Colorless fluid derived from blood by filtration through capillary walls. Carries lymphocytes in a special system of ducts and vessels

Chelate

Combine with a metal ion (Fe2+, Ca2+, Mg2+), reversibly and with high affinity

Fibroblast

Common cell type found in connective tissue. Secretes an extracellular matrix rich in collagen. Migrates and proliferates readily in wounded tissue and in tissue culture

pH

Common measure of the acidity of a solution: "p" refers to power of 10, "H" to hydrogen. Defined as the negative logarithm of the hydrogen ion concentration in moles per liter (M). Thus on the pH scale, pH 3 is acidic and pH 9 is alkaline.

Yeast

Common term for several families of unicellular fungi. Includes species used for brewing beer and making bread, as well as pathogenic species (that is, species that cause disease).

Leucine-rich repeat protein

Common type of receptor serine/threonine kinase in plants. Characterized by a tandem array of leucine-rich repeat sequences in the extracellular portion

Plasmodesmata

Communicating cell-cell junction in plants in which a channel of cytoplasm lined by plasma membrane connects two adjacent cells through a small pore in their cell walls.

Synapse

Communicating cell-cell junction that allows signals to pass from a nerve cell to another cell. In a chemical synapse the signal is carried by a diffusible neurotransmitter; in an electrical synapse a direct connection is made between the cytoplasms of the two cells via gap junctions.

Gap junction

Communication cell-cell junction that allows ions and small molecules to pass from the cytoplasm of one cell to the cytoplasm of the next. Each is composed of two connexions. Analogous to plasmodesmata in plants https://o.quizlet.com/7qzvc8KFPNgDgYoTeJl1Eg_m.jpg

cDNA

Complementary DNA. Molecule made as a copy of messenger RNA by reverse transcriptase and therefore lacking genomic introns.

M-phase Ck

Complex formed by an M-cyclin and the corresponding cyclin-dependent kinase

G1 Cdk

Complex formed in vertebrate cells by a G1 cyclin and the corresponding Cdk

G1/S Cdk

Complex formed in vertebrate cells by a G1/S cyclin and the corresponding Cdk

S-Cdk

Complex formed in vertebrate cells by and S-cyclin and the corresponding cyclin-dependent kinase (Cdk)

Extracellular matrix

Complex network made up of polysaccharides (cellulose or glycosaminoglycans) and proteins (collagen) secreted by cells. Serves as structural element in tissues and also influences their development and behavior

Chromatin

Complex of DNA, histones and nonhistone proteins in the nucleus of eukaryotic cells

Major histocompatibility complex

Complex of highly polymorphic genes in vertebrates. They code for a large gamily of cell-surface glycoproteins that bind to peptide fragments of foreign proteins and present them to T cells to induce an immune response

Condensin

Complex of proteins involved in chromosome condensation prior to mitosis

Kinetochore

Complex structure formed from proteins on a mitotic chromosome to which microtubules attach and which plays an active part in chromosomal movement to the poles. It forms on the centromere

Tertiary structure

Complex three-dimensional form of a folded polymer chain, especially a protein of RNA molecule.

Subunit

Component of a multicomponent complex-for example, one protein component of a protein complex or one polypeptide chain of a multichain protein.

Fatty acid

Compound that contains a carboxylic acid attached to a long hydrocarbon chain that can be used as energy source during metabolism and as a starting point for lipid synthesis https://o.quizlet.com/i/fdRPp7kvIP6mp96jm_W7Dg_m.jpg

Image processing

Computer treatment of images gained from microscopy that reveal information not immediately visible to the eye

Critical concentration

Concentration of a protein monomer that is in equilibrium with the assembled form of the protein (actin into actin filaments or tubulin into microtubules)

Chromosome

Condensed structure of a very long DNA molecule and associated proteins that carries the hereditary information of an organism. Evident in mitosis or meiosis

Fat cell

Connective-tissue cell that produces and stores fat in animals. Adipocyte

TATA box

Consensus sequence in the promoter region of many eukaryotic genes that binds a general transcription factor and hence specifies the position at which transcription is initiated.

Default pathway

Constitutive secretory pathway that automatically delivers material from the Golgi apparatus to the plasma membrane if no other sorting signals are present

Centromere

Constricted region of a mitotic chromosome that holds sister chromatids together. Site where the kinetochore forms that captures microtubules from the mitotic spindle

Diploid

Containing two sets of homologous chromosomes and therefore two copies of genetic loci

Cytoplasm

Contents of a cell contained within its plasma membrane but in eukaryotes, outside of the nucleus

Cytosol

Contents of the main compartment of the cytoplasm, excluding membrane-bounded organelles. https://o.quizlet.com/-0-dZadB1En9orz0Ds9BMA_m.jpg

RNA processing control

Control of gene expression by controlling how the RNA transcript is spliced or otherwise processed.

Transcriptional control

Control of gene expression by controlling when and how often the gene is transcribed.

Translational control

Control of gene expression by selection of which mRNAs in the cytoplasm are translated by ribosomes.

Transcription (DNA transcription)

Copying of one strand of DNA into a complementary RNA sequence by the enzyme RNA polymerase.

Prenylation

Covalent attachment of an isoprenoid lipid group to a protein.

High-energy bond

Covalent bond whose hydrolysis releases an unusually large amount of free energy. A group linked to a molecule by such bod is readily transferred from one molecule to another (phosphodiester bonds in ATP and thirster linkage in acetyl CoA)

Disulfide bond

Covalent linkage formed between two sulfhydryl groups on cysteine. For extracellular proteins, a common way of joining two proteins together or linking different parts of the same protein, formed in the ER

Nucleation

Critical stage in the assembly of a polymeric structure (e.g. microtubule) at which a small cluster of monomers aggregates in the correct arrangement to initiate rapid polymerization. Rate-limiting step in an assembly process

Heme

Cyclic organic molecule containing an iron atom that carries oxygen in hemoglobin and carries an electron in cytochromes

Interferon-gamma

Cytokine secreted by certain types of T cells after activation, and which enhances the anti-viral response and macrophage activation

Plastid

Cytoplasmic organelle in plants, bounded by a double membrane, that carries its own DNA and is often pigmented. Chloroplasts are plastids.

Focal adhesion kinase

Cytoplasmic tyrosine kinases present at cell-matrix junctions in association with cytoplasmic tails of integrins

Dynamin

Cytosolic GTPase that binds to the neck of a clathrin-coated vesicle in the process of budding from the membrane and which is involved in completing vesicle formation https://o.quizlet.com/goPzCh9Rbhtms4Pfc05zcg_m.png

Natural killer cell

Cytotoxic cell of the innate immune system that can kill virus-infected cells

CG island

DNA region with a high density of CG sequences. Usually remain unmethylated

Mismatch repair

DNA repair process that corrects mismatched nucleotides inserted during DNA replication. A short stretch of newly synthesized DNA including the mismatched nucleotide is removed and replaced with the correct sequence with reference to the template strand

Insulator element

DNA sequence that blocks the interaction between promoters and enhancers

Regulatory sequence

DNA sequence to which a gene regulatory protein binds to control the rate of assembly of the transcriptional complex at the promoter.

Gene control region

DNA sequences required to initiate transcription of a given gene and control the rate of initiation

Homeodomain

DNA-binding domain that defines a class of gene regulatory proteins important in animal development

Helix-loop-helix

DNA-binding structural motif present in many gene regulatory proteins

Zinc finger

DNA-binding structural motif present in many gene regulatory proteins. Composed of a loop of polypeptide chain held in a hairpin bend bound to a zinc atom.

Probe

Defined fragment of RNA or DNA, radioactively or chemically labeled, used to locate specific nucleic acid sequences by hybridization.

Proteolysis

Degradation of a protein by hydrolysis at one or more of its peptide bonds.

Brush border

Dense covering of microvilli on the apical surface of epithelial cells in intestine/kidney that aid absorption by increasing the cell's surface area

Anchorage dependence

Dependence of cell growth on attachment to a subtratum

Polyploid

Describes a cell or an organism that contains more than two sets of homologous chromosomes.

Polymorphic

Describes a gene with many different alleles, none of which is predominant in the population.

Saturated

Describes a molecule containing carbon-carbon bonds that has only single covalent bonds.

Unsaturated

Describes a molecule that contains one or more double or triple carbon-carbon bonds, such as isoprene or benzene.

Hydrophobic

Describes a non polar molecule or part of a molecule that cannot form energetically favorable interactions with water and therefore it is insoluble in water (water hating, lipophilic)

Hydrophilic

Describes a polar molecule or part of a molecule that forms enough energetically favorable interactions with water molecules to dissolver readily in water (water loving <3)

Molar

Describes a solution with a concentration of 1 mole of a substance dissolved in 1 liter of solution

Hypertonic

Describes any medium with a sufficiently high concentration of solutes to cause water to move out of a cell due to osmosis

Hypotonic

Describes any medium with a sufficiently low concentration of solutes that causes water to move into a cell due to osmosis

Post-translational

Describes any process involving a protein that occurs after protein synthesis is completed.

Co-translational

Describes import of a protein into the endoplasmic reticulum before the polypeptide chains completely synthesized

Homologous

Describes organs or molecules that are similar because of their common evolutionary origin. Specifically describes similarities in protein or nucleic acids sequence

Dorsoventral

Describes the axis running from the back to the belly of an animal or from the upper side to the underside of a structure

Osmolarity

Describes the concentration of a solution terms of the osmotic pressure it can exert

Malignant

Describes tumors and tumor cells that are invasive and/or able to undergo metasis

Cell fate

Describes what a particular cell at a given stage of development will normally give rise to

DNA sequencing

Determination of the order of nucleotides in a DNA molecule

Embryogenesis

Development of an embryo from a fertilized egg or zygote

Spermatogenesis

Development of sperm.

Restriction map

Diagrammatic representation of a DNA molecule indicating the sites of cleavage by various restriction enzymes.

Position effect

Differences in gene expression that depend on the position of the gene on the chromosome and probably reflect differences in the state of the chromatin along the chromosome.

Autophagy

Digestion of worn-out organelles by the cell's own lysosomes

Heterozygote

Diploid cell or individual having two different alleles of one or more specified genes

Homozygote

Diploid cell or organism having two identical alleles of a specific gene or set of genes

Zygote

Diploid cell produced by fusion of a male and female gamete. A fertilized egg.

Chemotaxis

Directed movement of a cell or organism towards or away form a diffusible chemical

Axonal transport

Directed transport of organelles and molecules along a nerve cell axon https://o.quizlet.com/i/PFT0PnAOySF-PUhNqrBhCg_m.jpg

Sucrose

Disaccharide composed of one glucose unit and one fructose unit. The major form in which glucose is transported between plant cells.

Division II of meiosis

Division in which the chromatids of each duplicated chromosome are segregated to opposite poles of the dividing cell

Division I (meiosis)

Division in which the members of each pair of duplicated homologous chromosomes are segregated to opposite poles of the dividing cell

Cytokinesis

Division of the cytoplasm of a plant/animal cell into 2, different from the divisions of its nucleus (mitosis)

Mitosis

Division of the nucleus of a eukaryotic cell, involving condensation of the DNA into visible chromosomes, and separation of the duplicated chromosomes to form two identical sets

Nuclear envelope

Double membrane surrounding the nucleus. Consists of an outer and inner membrane and is perforated by nuclear pores https://o.quizlet.com/i/LhyVPUJ18y3CYXQVmAFyjQ_m.jpg

Proton-motive force

Driving force that moves protons across a membrane as a result of an electrochemical proton gradient.

Bivalent

Duplicated chromosome paired with its homologous duplicated chromosome at the beginning of meiosis. 4 chromatids. 2 sister chromatids of two homologous chromosomes https://o.quizlet.com/X8rEA8r84OHUkbhBdwbR2g_m.png

Centrosome cycle

Duplication of the centrosome during interphase and its separation during mitosis to form poles of mitotic spindle

Fluorescein

Dye that fluoresces green when illuminated with blue or UV light

Blastula

Early stage of an animal embryo, constituting of a hollow ball of cells before gastrulation begins https://o.quizlet.com/GvZK4HXqaw6tPneUBmS-IQ_m.png

Action potential - Nerve impulse

Electrical excitation in the plasma membrane of cells. Makes long distance nervous system signaling possible.

Immunogold electron microscopy

Electron microscopy technique in which cellular structures or molecules of interest are labeled with antibodies tagged with electron-dense gold particles.

Cryoelectron microscopy

Electron microscopy technique in which the objects to be viewed are rapidly frozen

Iron-sulfur center

Electron transporting group consisting of either two or four iron atoms bound to an equal number of sulfur atoms, found in a class of electron-transport proteins https://o.quizlet.com/ap7Q77OmEvFiBItIhFa1jw_m.png

Respiratory chain

Electron-transport chain in the inner mitochondrial membrane that receives high-energy electrons derived from the citric acid cycle and generates the proton gradient across the membrane that is used to power ATP synthesis.

Patch-clamp recording

Electrophysiological technique in which a tiny electrode tip is sealed onto a patch of cell membrane, making it possible to record the flow of current though individual ion channels in the patch https://o.quizlet.com/MYU87T-zczSLiNpArCmB5Q_m.png

Motif

Element of structure or pattern that recurs in many contexts. A small structural domain that can be recognized in a variety of proteins

Photon

Elementary particle of light and other electromagnetic radiation.

Ectoderm

Embryonic tissue that is the precursor of the epidermis and nervous system

Endoderm

Embryonic tissue that is the precursor of the gut and associated organs

Telomere

End of a chromosome, associated with a characteristic DNA sequence that is replicated in a special way. Counteracts the tendency of the chromosome otherwise to shorten with each round of replication.

Amino terminus

End of a polypeptide chain carrying a free alpha amino group

Carboxyl terminus

End of a polypeptide chain that carries a free carbonyl group https://o.quizlet.com/bv2Al5BJyln-AczYoQD98Q_m.jpg

Rough endoplasmic reticulum (rough ER)

Endoplasmic reticulum with ribosomes on its cytosolic surface. Involved in the synthesis of secreted and membrane-bound proteins.

Fat

Energy-storage lipid in cells composed of triglycerides-fatty acids esterified with glycerol

GTPase

Enzyme activity that converts GTP to GDP. Also common name for monomeric GTP-binding proteins

Phospholipase C-beta (PLC-B)

Enzyme bound to the cytoplasmic face of the plasma membrane that converts membrane phosphatidylinositol 4,5-bisphosphate to diacylglycerol (which remains in the plasma membrane) and inositol 1,4,5-triphosphate (IP3). It is activated by certain G proteins to trigger the inositol phospholipid signaling pathway.

ATP synthase

Enzyme complex in the inner membrane of mitochondria and chloroplast thylakoid membrane that catalyzes the formation of ATP from ADP and inorganic phosphate during oxidative phosphorylation and photosynthesis, respectively https://o.quizlet.com/6QTWr4l4k4I7OkuvJVp5ng_m.png

Reverse transcriptase

Enzyme first discovered in retroviruses that makes a double-stranded DNA copy from a single-stranded RNA template molecule.

Protease

Enzyme such as trypsin that degrades proteins by hydrolyzing some of their peptide bonds.

Aminoacyl-tRNA synthetase

Enzyme that attaches the correct amino acid to a tRNA

DNA topoisomerase

Enzyme that binds to DNA and reversibly breaks a phosphodiester bond in one or both strands allowing the DNA to rotate at that point. It prevents DNA tangling during replication

Lipase

Enzyme that catalyzes the cleavage of fatty acids from the glycerol moiety of a triglyceride

Lysozyme

Enzyme that catalyzes the cutting of polysaccharide chains in the cell walls of bacteria

ATPase

Enzyme that catalyzes the hydrolysis of ATP

RNA polymerase

Enzyme that catalyzes the synthesis of an RNA molecule on a DNA template from nucleoside triphosphate precursors.

Ribonuclease

Enzyme that cuts an RNA molecule by hydrolyzing one or more of its phosphodiester bonds.

Telomerase

Enzyme that elongates telomere sequences in DNA.

DNA helicase

Enzyme that is involved in opening the DNA helix into its single strands for DNA replication

DNA ligase

Enzyme that joins the ends of two strands of DNA together with a covalent bond to make a continuous DNA strand

Ligase

Enzyme that joins together two molecules in an energy-dependent process. e.g. joining together DNA nucleotides end to end through phosphodiester bonds

Topoisomerase (DNA topoisomerase)

Enzyme that makes reversible cuts in a double-helical DNA molecule for the purpose of removing knots or unwinding excessive twists.

Phosphoprotein phosphatase

Enzyme that removes a phosphate group from a protein by hydrolysis.

Signal peptidase

Enzyme that removes a terminal signal sequence from a protein once the sorting process is complete.

Phosphatase

Enzyme that removes phosphate groups from a molecule.

DNA polymerase

Enzyme that synthesizes DNA by forming phosphodiester bonds between nucleotides using a DNA template as a guide

DNA primase

Enzyme that synthesizes a short RNA sequence complementary to a DNA template in order to function as a primer and initiate DNA replication

Protein kinase

Enzyme that transfers the terminal phosphate group of ATP to a specific amino acid of a target protein.

Catabolism

Enzyme-catalyzed reactions in a cell by which complex molecules are degraded to simpler ones with release of energy. Intermediates are called catabolites

Epidermis

Epithelial layer covering the outer surface of the body. It has different structures in different animal groups and it also names the outer layer of plant tissue

Coiled-coil

Especially stable rodlike structure in proteins formed by two alpha helices coiled around each other

Internal membrane

Eukaryotic cell membrane other than pasma membrane (ER of Golgi membranes)

Phylogeny

Evolutionary history of an organism or group of organisms, often presented in chart form as a phylogenetic tree.

Chromosomal crossing over

Exchange of DNA between paired homologous chromosomes in meiosis, in which genetic recombination and crossovers are visible

Clonal selection theory

Explains how adaptive immune system can respond to millions of different antigens in a highly specific way

Dendrite

Extension of a nerve cell, typically branched and relatively short, that receives stimuli from other nerve cells

Activation Energy

Extra energy possessed by atoms/molecules apart from its ground-state energy that is used to undergo chemical reactions

Fibronectin

Extracellular matrix glycoprotein that binds to membrane receptors integrins. This protein is involved in adhesion of cells to the matrix and the guidance of migrating cells during embryogenesis https://o.quizlet.com/iP3yZdzrTgZtVZdCB6dKxw_m.png

Laminin

Extracellular matrix protein found in basal laminae, where it forms a sheetlike network

Signal molecule

Extracellular or intracellular molecule that cues the response of a cell to the behavior of other cells or objects in the environment.

Growth factor

Extracellular polipeptide signal molecule that can stimulate a cell to grow or proliferate.

Cytokine

Extracellular signal protein or peptide that acts as a local mediator in cell-cell communication

Survival factor

Extracellular signal required for a cell to survive; in its absence the cell will undergo apoptosis and die.

Collagen fibril

Extracellular structure formed by self assembly of secreted collagen subunits. Abundant constituent of the extracellular matrix

Collagen

FIBROUS protein rich in GLYCINE and PROLINE that is a major component of the extracellular matrix and connective tissues. Type I, skin, tendon, bone. Type II, cartilage. Type IV, basal laminae

trans face

Face of a Golgi stack at which material leaves the organelle for the cell surface or another cell compartment. It is adjacent to the trans Golgi network.

cis face

Face of a Golgi stack where material enters the organelle. Adjacent to the cis Golgi network https://o.quizlet.com/cL5JPd0zJbcql3QpihgLbg_m.png

Src family

Family of cytoplasmic tyrosine kinases that associate with the cytoplasmic domains of some enzyme-linked receptors (for example, the T cell antigen receptor) that lack intrinsic tyrosine kinase activity. They transmit a signal onwards by phosphorylating the receptor itself and other signaling proteins.

Fc receptor

Family of receptors specific for the Fc region (constant region "bottom of the Y") of various classes of antibodies

Adipocyte

Fat cell

Connective tissue cell

Fibroblasts, cartilage cells (chondrocytes), bone cells (osteoblasts, osteocytes), fat cells (adipocytes), smooth muscle cells. Any of the various cell types found in connective tissue.

Nuclear lamina

Fibrous meshwork of proteins on the inner surface of the inner nuclear membrane. It is made up of a network of intermediate filaments formed from nuclear lamins https://o.quizlet.com/i/_8PLXchRgmDt88H5GTQADA_m.jpg

Intermediate filament

Fibrous protein filament (10 nm in diameter) that forms roselike networks in animal cells. One of the three most prominent types of cytoskeleton filaments

Telophase

Final stage of mitosis in which the two sets of separated chromosomes decondense and become enclosed by nuclear envelopes.

NADH dehydrogenase complex

First of the three electron-driven proton pumps in the mitochondrial respiratory chain. It accepts electrons from NADH

Prophase

First stage of mitosis, during which the chromosomes are condensed but not yet attached to a mitotic spindle.

Endothelial cell

Flattened cell type that forms a sheet called endothelium that line all blood vessels

Cisterna

Flattened membrane-bounded compartment found in the Golgi apparatus or endoplasmic reticulum

Cell plate

Flattened membrane-bounded structure that forms fusing vesicles in the cytoplasm of a dividing plant cell and is the precursor of the new cell wall

Thylakoid

Flattened sac of membrane in a chloroplast that contains chlorophyll and other pigments and carries out the light-trapping reactions of photosynthesis. Stacks of thylakoids form the grana of chloroplasts.

Lamellipodium

Flattened, sheetlike protrusion supported by a meshwork of actin filaments, which is extended at the leading edge of a crawling animal cell

Cryptochrome

Flavoprotein responsive to blue light (in animals involved with circadian rhythms)

Green Fluorescent Protein

Fluorescent protein isolated from a jellyfish. Widely used as a marker in cell biology

hydrophobic force

Force exerted by the hydrogen-bonded network of water molecules that brings two non polar surfaces together by excluding water between them

Radioactive isotope

Form of an atom with an unstable nucleus that emits radiation as it decays.

Cartilage

Form of connective tissue composed of cells embedded in a matrix rich in collagen and chondroitin sulfate

Oogenesis

Formation and maturation of oocytes in the ovary

Cellularization

Formation of cells around each nucleus in a multinucleate cytoplasm, transforming it into a multicellular structure

Diplotene

Fourth stage of division of meiosis, in which chiasmata are first seen https://o.quizlet.com/o9xANefiGbB06HXFNNp-Iw_m.jpg

Cell-free system

Fractionated cell homogenate that retains a particular biological function of the intact cell and in which biochemical reactions and cell processes can be more easily studied

Standard free-energy change

Free-energy change of two reacting molecules at standard temperature and pressure when all components are present at a concentration of 1 mole per liter.

Protozoa

Free-living or parasitic, nonphotosynthetic, single-celled, motile eukaryotic organisms, such as Paramecium and Amoeba. Free-living protozoa feed on bacteria or other microorganisms.

Karyotype

Full set of chromosomes of a cell arranged with respect to size, shape and number

Acyl group

Functional group derived from a carboxylic acid. (R-C=0) R is an alkyl group

Alkyl group

Functional group of covalently linked carbon and hydrogen atoms produced by removing a hydrogen from an alkane

Fertilization

Fusion of a male and female haploid gamete to produce a diploid zygote in order to produce a new individual

Inhibitory G protein

G protein that can regulate ion channels and inhibit the enzyme adenylyl cyclase

Stimulatory G protein (Gs)

G protein that, when activated, activates the enzyme adenylyl cyclase and thus stimulates the production of cyclic AMP.

Rhodopsin

G-protein-linked light-sensitive receptor protein in the rod photoreceptor cells of the retina.

G2 phase

Gap 2 phase of the eukaryotic cell division cycle, between the end of DNA synthesis and the beginning of mitosis

G1 phase

Gap1 phase of the eukaryotic cell-division cycle, between the end of cytokinesis and DNA synthesis

Nitric oxide NO

Gaseous signal molecule in both animals, where it regulates smooth muscle contraction, and in plants, where it is involved in responses to injury or infection

Gene repressor protein

Gene regulatory protein that prevents the initiation of transcription

V gene segment

Gene segment encoding most of the variable region of the polypeptide chains of immunoglobulins and T cell receptor.

Housekeeping gene

Gene serving a function required in all the cell types of an organism regardless of their specialized role and that are being transcribed constitutively

Tumor suppressor gene

Gene that appears to prevent formation of a cancer. Loss-of-function mutations in such genes enhance susceptibility to cancer.

Virulence gene

Gene that contributes to an organism's ability to cause disease.

Cell-division-cycle gene (cdc)

Gene that controls a specific step in the eukaryotic cell cycle

Pseudogene

Gene that has accumulated multiple mutations that has rendered it inactive and nonfunctional.

rRNA gene

Gene that specifies a ribosomal RNA (rRNA).

White blood cell (leukocyte)

General name for all the nucleated blood cells lacking hemoglobin. Includes lymphocytes, neutrophils, eosinophils, basophils, and monocytes.

Respiration

General term for a process in a cell involving the oxidative breakdown of sugars or other organic molecules, and requiring the uptake of O2 while producing CO2 and H2O as waste products.

Phagocyte

General term for a professional phagocytic cell-that is, a cell such as a macrophage or neutrophil that is specialized to take up particles and microorganisms by phagocytosis.

DNA tumor virus

General term for a variety of different DNA viruses that can cause tumors

Residue

General term for the unit of a polymer. That portion of a sugar, amino acid, or nucleotide that is retained as part of the polymer chain during the process of polymerization.

Hemopoiesis

Generation of blood cells, mainly in the bone marrow

Carcinogenesis

Generation of cancer

Genotype

Genetic constitution of an individual cell or organism

Saccharomyces

Genus of yeasts that reproduce asexually by budding or sexually by conjugation. Economically important in brewing and baking, they are also widely used in genetic engineering and as simple model organisms in the study of eukaryotic cell biology.

Polytene chromosome

Giant chromosome in which the DNA has undergone repeated replication without separation into new chromosomes.

Schwann cell

Glial cell responsible for forming myelin sheaths in the peripheral nervous system.

Zona pellucida

Glycoprotein layer on the surface of the unfertilized egg. It is often a barrier to fertilization across species.

Escherichia coli

Gram-negative, facultatively anaerobic, rod-shaped bacterium commonly found on the lower intestine of warm-blooded organisms Widely used in biomedical research

Molecule

Group of atoms joined together by covalent bonds

DNA repair

Group of biochemical processes that correct damaged DNA

Imaginal disc

Group of cells that are set aside in the Drosophila embryo and which will develop into an adult structure

Erythropoietin

Growth factor that stimulates the production of red blood cells. Produced by the kidney and acts on precursor cells in bone marrow https://o.quizlet.com/i/OlYGT8sx5XS-M3Y72g9--w_m.jpg

Angiogenesis

Growth of new blood vessels by sprouting from existing ones (angeîon, "vessel") https://o.quizlet.com/guE0.pbvHLiMOA34YhDBVg_m.png

GTP

Guanosine 5'-triphosphate. Nucleoside triphosphate produced by phosphorylating GDP. It releases a large amount of free energy on hydrolysis of its terminal phosphate group. Special role in microtubule assembly, protein synthesis and cell signaling

Connexon

H2O filled pore in the plasma membrane formed by a ring of 6 protein subunits. Part of a gap junction which allows the formation of a continuous channel between two cells

Hydronium ion

H3O+ water molecule associated with an additional proton

High-performance liquid chromatography

HPLC. Type of chromatography that uses a column with tiny beads of matrix, the solution to be separated is used through under high pressure

Cillium

Hairlike extension of eukaryotic cells containing microtubules that is capable of performing repeated beating movements. Found in the cell surface and responsible for swimming of unicellular organisms

Amphipathic

Having both hydrophobic and hydrophilic region. Phospholipid or detergent molecules.

Haploid

Having only one set of chromosomes, as in a sperm cell or a bacterium

Basic

Having the properties of a base

Actin filament

Helical polymer of actin proteins (F-actin) that forms microfilaments. Forms cytoskeleton in eukaryotes.

hnRNP protein

Heterogeneous nuclear ribonuclear protein. Any of a group of proteins that assemble on newly synthesized RNA, organizing it into a more compact form

Thioester bond

High-energy bond formed by a condensation reaction between an acid (acyl) group and a thiol group (-SH); seen, for example, in acetyl CoA and in many enzyme-substrate complexes.

Mitotic chromosome

Highly condensed duplicated chromosome with the two new chromosomes still held together at the centromere as sister chromatids

Adrenaline - epinephrine

Hormone released by the adrenal gland and some neurons in response to stress. "fight or flight" (increase heart rate and blood sugar levels)

HIV

Human Immunodeficiency virus. Retrovirus that is the cause of AIDS

Alkene

Hydrocarbon joined by one or more C-C double covalent bonds

Alkane

Hydrocarbon joined by single covalent bonds

Acid hydrolase

Hydrolytic enzyme that has its optimal activity at acidic pH (~5) (proteases, nucleases, etc). Found in lysosomes

Stop-transfer signal

Hydrophobic amino acid sequence that halts translocation of a polypeptide chain through the endoplasmic reticulum membrane, thus anchoring the protein chain in the membrane.

Ethyl

Hydrophobic chemical group derived from ethane https://o.quizlet.com/i/5cdr_5ekOXXmjjg-7eziwQ_m.jpg

Methyl

Hydrophobic chemical group derived from methane https://o.quizlet.com/i/WJaEJ1qa4CAYFIqPn-4Qkg_m.jpg

Steroid

Hydrophobic lipid molecule with a characteristic four-ringed structure. Many important hormones such as estrogen and testosterone are steroids.

Elastin

Hydrophobic protein that forms elastic fibers that give tissues their stretchability and resilience

Metaphase plate

Imaginary plane at right angles to the mitotic spindle and midway between the spindle poles; the plane in which chromosomes are positioned at metaphase

Pre-B cell

Immediate precursor of a B cell.

Restriction point

Important checkpoint in the mammalian cell cycle. Passage through the restriction point commits the cell to enter S phase. It corresponds to Start in the yeast cell cycle.

Toll-like receptor family (TLR)

Important family of mammalian pattern recognition receptors abundant on macrophages, neutrophils, and the epithelial cells of the gut. They recognize pathogen-associated immunostimulants such as lipopolysaccharide and peptidoglycan.

Operon

In a bacterial chromosome, a group of contagious genes that are transcribed into a single mRNA molecule

in vivo

In an intact cell or organisms (latin for in life)

Mating-type locus

In budding yeast, the locks that determines the mating type (alpha or a) of the haploid yeast cell

Vector

In cell biology, the DNA of an agent (virus or plasmid) used to transmit genetic material to a cell or organism.

Reaction

In chemistry, any process in which one molecule is converted into another by the removal or addition of atoms, or in which the arrangement of atoms in a molecule or molecules is altered by a change in chemical bonds.

Recessive

In genetics, refers to the member of a pair of alleles that fails to be expressed in the phenotype of the organism when the dominant allele is present. Also refers to the phenotype of an individual that has only the recessive allele.

Overlap microtubule

In mitotic or meiotic single, a microtubule interdigitating at the equator with the microtubules emanating from the other pole

Module

In proteins or nucleic acids, a unit of structure or function that is found in a variety of different contexts in different molecules

Polar

In the electrical sense, describes a structure (for example, a chemical bond, chemical group, or molecule) with positive charge concentrated toward one end and negative charge toward the other as a result of an uneven distribution of electrons. Polar molecules are likely to be soluble in water.

Animal pole

In yolky eggs (embryo) the end free of yolk that consists of small cells and divides rapidly.

X-inactivation

Inactivation of one copy of the X chromosome in the somatic cells of female mammals.

Positional information

Information supplied to or possessed by cells according to their position in a multicellular organism. A cell's internal record of its positional information is called its positional value.

Transcription attenuation

Inhibition of gene expression in bacteria by the premature termination of transcription.

Microinjection

Injection of molecules into a cell using a micropipette

Inner membrane

Innermost of two membranes surrounding an organelle. In mitochondria, it carries respiratory electron transport chain

Inner nuclear membrane

Innermost of two nuclear membrane, Contains binding sites for chromatin and nuclear lamina on its internal face

Cofactor

Inorganic ion or coenzyme required for an enzyme's activity

Myelin sheath

Insulating layer of specialized cell membrane wrapped around vertebrate axons. Produced by oligodendrocytes in the central nervous system and by Schwann cells in the peripheral nervous system

Circadian clock

Internal cyclical process that produces a particular change in a cell/organism with a period of around 24 hours

Receptor-mediated endocytosis

Internalization of receptor-ligand complexes from the plasma membrane by endocytosis. It is used to take up some macromolecules, such as cholesterol-containing lipoproteins, from the extracellular fluid, and is also a means of recycling receptor proteins once they have bound their ligands.

Symbiosis

Intimate association between two organisms of different species from which both derive a long-term selective advantage.

Caspase

Intracellular proteases involved in the apoptosis cellular initiation

IAP family

Intracellular protein inhibitor in apoptosis

Nuclear receptor superfamily

Intracellular receptors for hydrophobic signal molecules such as steroids and retinoid acid. The receptor-ligand complex acts as a transcription factor in the nucleus

Transfection

Introduction of a foreign DNA molecule into a eukaryotic cell. It is usually followed by expression of one or more genes in the newly introduced DNA.

Caveola

Invaginations at the cell surface that can bud off internally to form pinocytic vesicles and form lipid rafts (regions of membrane rich lipids) https://o.quizlet.com/BGgWco7PdWo4BKD.4CaZnw_m.png

Transmitter-gated ion channel

Ion channel in the postsynaptic plasma membranes of nerve and muscle cells that opens only in response to the binding of a specific extracellular neurotransmitter. The resulting inflow of ions leads to the generation of a local electrical signal in the postsynaptic cell.

Fungus

Kingdom of eukaryotic organisms that includes the unicellular organisms of yeast and molds and multicellular organisms like mushrooms. Cause many plant diseases and some animal diseases

Low-density lipoprotein

LDL. Large complex composed of a single protein molecule and many esterified cholesterol molecules, together with other lipids. The form in which cholesterol is transported in the blood and taken up into cells

Endoplasmic reticulum

Labyrinthine membrane-bounded compartment in the cytoplasm of eukaryotic cells, where lipids are synthesized and membrane-bound proteins and secretory proteins are made

Nonpolar

Lacking any asymmetric accumulation of positive and negative charge. Generally insoluble in water

Spliceosome

Large assembly of RNA and protein molecules that performs pre-mRNA splicing in eukaryotic cells.

Pseudopodium

Large cell-surface protrusion formed by amoeboid cells are as they crawl. More generally, any dynamic actin-rich extension of the surface of an animal cell.

Ig superfamily

Large family of proteins that contain immunoglobulin domains. Most are involved in cell-cell interactions or antigen recognition

Transforming growth factor-beta superfamily (TGF-B superfamily)

Large family of structurally related, secreted proteins that act as hormones and local mediators to control a wide range of functions in animals, including during development. It includes TGF-B, activins, and bone morphogenetic proteins (BMPs).

SNAREs

Large family of transmembrane proteins present in organelle membranes and the vesicles derived from them. They are involved in guiding vesicles to their correct destinations. They exist in pairs - a v-SNARE in the vesicle membrane that binds specifically to a complementary t-SNARE in the target membrane.

Recycling endosomes

Large intracellular membrane-bounded vesicle formed from a fragment of an endosome that is an intermediate stage on the passage of recycled receptors back to the cell membrane.

Phagosome

Large intracellular membrane-bounded vesicle that is formed as a result of phagocytosis. Contains ingested extracellular material.

Polymer

Large molecule made by covalently linking multiple identical or similar units (monomers) together.

Nuclear pore complex

Large multiprotein structure forming a channel through the nuclear envelope that allows selected molecules to move between nucleus and cytoplasm

Megakaryocyte

Large myeloid cell with a multilobed nucleus that remains in the bone marrow when mature. Buds off platelets from long cytoplasmic processes

RNA polymerase II holoenzyme

Large pre-assembled complex of RNA polymerase II, most of the general transcription factors required for its function, and the mediator protein complex.

Proteasome

Large protein complex in the cytosol with proteolytic activity that is responsible for degrading proteins that have been marked for destruction by ubiquitylation or by some other means.

Origin Recognition Complex

Large protein complex that is bound to the DNA at origins of replication in eukaryotic chromosomes throughout the cell cycle

Chlorophyll

Light-absorbing green pigment that plays a central part in photosynthesis in bacteria, plants and algae

Photosynthetic electron-transfer

Light-driven reactions in photosynthesis in which electrons move along the electron-transport chain in the thylakoid membrane, generating ATP and NADPH.

Euchromatin

Lightly packed form of chromatin that is enriched in genes associated with active transcription

Phospholipase C-gamma (PLC-gamma)

Like phospholipase C-beta, an enzyme that cleaves inositol phospholipids to diacylglycerol and IP3 to trigger the inositol phospholipid signaling pathway. Activated by certain receptor tyrosine kinases.

HeLa cell

Line of human epithelial cells that grows vigorously in culture. Derived from a human cervical carcinoma

Polysaccharide

Linear or branched polymer of monosacccharides. They include glycogen, starch, hyaluronic acid, and cellulose.

Polypeptide

Linear polymer composed of multiple amino acids. Proteins are large polypeptides, and the two terms can be used interchangeably.

Cholesterol

Lipid molecule with a four-ring steroid. Important component of plasma membrane in animal cells

Diacylglycerol

Lipid produced by cleavage of inositol phospholipids in response to extracellular signals. Composed of two fatty acid chains linked to glycerol. It serves as a signaling molecule to help activate protein kinase C

Hepatocyte

Liver cell

inflammatory response

Local response of a tissue to injury or infection (tissue redness, swelling, heat, pain). Caused by an invasion of white blood cells and their release of mediators like histamine

Replication origin

Location on a DNA molecule at which duplication of the DNA begins.

Microtubule

Long hollow cylindrical structure composed of tubular. One of the three major classes of filaments of the cytoskeleton

Axon

Long nerve cell that is capable of conducting nerve impulses over long distances in order to deliver signal to other cells https://o.quizlet.com/i/Rz2MYdOt7YPmsTKaFwAJzg_m.jpg

Interphase

Long period of the cell cycle between mitosis events. Includes G1, S phase and G2 phase

Neurite

Long process growing from a nerve cell in culture. A generic term that does not specify whether the process is an axon or a dendrite

Myofibril

Long, highly organized bundle of actin, myosin, and other proteins in the cytoplasm of muscle cells that contracts by a sliding filament mechanism

Glycosaminoglycan

Long, linear, highly charged polysaccharide composed of a repeating pair of sugars, one of which is always an amino sugar. Mainly found covalently linked to a protein core in extracellular matrix proteoglycans

Flagellum

Long, whiplike protrusion whose undulations drive a cell through a fluid medium. It is used as locomotion or as a sensory organelle. Their structure and composition differs greatly in prokaryotes and eukaryotes

Long-term potentiation

Long-lasting increase in the sensitivity of certain synapses in the hippocampus. Induced by a short burst of repetitive firing in the presynaptic neurons https://o.quizlet.com/a1yEDky.nGvz3PWfLvVB-Q_m.jpg

Immunological memory

Long-lived state that follows a primary immune response to many antigens. In which subsequent encounter with that antigen will provoke a rapid secondary immune response

Oxidation

Loss of electrons from an atom, as occurs during the addition of oxygen to a molecule or when a hydrogen is removed. Opposite of reduction

Biotin

Low-molecular-weight molecule used as a coenzyme. Used to covalently label proteins for avidin detection

Peripheral lymphoid organ (secondary lymphoid organ)

Lymphoid organ in which T cells and B cells interact with foreign antigens. Examples are spleen, lymph nodes, and mucosal-associated lymphoid tissue.

Central lymphoid organ

Lymphoid organ in which lymphocytes develop. In animals this is the thymus and the bone marrow

Microtubule-associated protein

MAP. Any protein that binds to microtubules and modifies their properties, e.g. structural proteins, such as MAP-2 or motor proteins, such as dynein

Microtubule-organizing center

MTOC. Region in a cell, such as a centrosome or a basal body, from which microtubules grow

Osteoclast

Macrophage-like cell that erodes bone, enabling it to be remodeled during growth and in response to stresses throughout life

Central nervous system

Main information-processing organ of the nervous system. In vertebrates it consists of the brain and spinal cord

Cell body

Main part of a nerve cell that contains the nucleus (other parts are dendrites and axons) https://o.quizlet.com/10hETpubs7lb6cmRo7HrjQ_m.png

Septate junction

Main type of occluding cell junction in invertebrates; their structure is distinct from that of vertebrate tight junctions.

Calvin cycle

Major metabolic pathway by which CO2 is incorporated into carbohydrate during the carbon fixation photosynthesis stage in plants

Enzyme-linked receptor

Major type of cell-surface receptor in which the cytoplasmic domain ether has enzymatic activity itself or is associated with an intracellular enzyme. Enzymatic activity is stimulated by ligand binding to the receptor

Genetic map

Map of the chromosomes in which the distance of genes relative to each other is determined by the amount of genetic recombination that occurs between them

Syncytium

Mass of cytoplasm containing many nuclei enclosed by a single plasma membrane. Typically the result either of cell fusion or of a series of incomplete division cycles in which the nuclei divide but the cell does not.

Affinity constant Ka

Measure of binding strength of the components of a complex

Dissociation constant

Measure of the tendency of a complex to dissociate

Cell wall

Mechanically strong extracellular matrix deposited by a cell outside of its plasma membrane. Prominent in prokaryotes, algae, fungi and plants https://o.quizlet.com/i/i-6_WQ3lZeky3-K5ABgDig_m.jpg

Chemiosmotic coupling

Mechanism in which a pH gradient across a membrane is used to drive an energy-requiring process (ATP production of flagella rotation)

Selectin

Member of a family of cell-surface carbohydrate-binding proteins that mediate transient, Ca2+-dependent cell-cell adhesion in the bloodstream, for example between white blood cells and the endothelium of the blood vessel wall.

Isoprenoid

Member of a family of lipid molecules with a carbon skeleton based on multiple five-carbon isoprene units https://o.quizlet.com/aYMBm3VBVWrIi7JmbmZiLg_m.png

Keratin

Member of a family of proteins that form keratin intermediate filaments, mainly in epithelial cells. Found in hair, nails and feather

Dominant

Member of a pair of alleles that is expressed in the phenotype of the organism while the other allele is not, even though both are present

Archea

Members of one of the two major divisions of prokaryotes (other, bacteria)

Adenylate cyclase

Membrane bound enzyme that catalyzes ATP -> cAMP

Acetylcholine receptor

Membrane bound protein (ion channel) that when bound to acetylcholine converts that chemical signal to an ELECTRICAL one

Glycolipid

Membrane lipid molecule with a sugar residue or oligosaccharide attached to the polar headgroup

Multipass transmembrane protein

Membrane protein in which the polypeptide chain crosses the lipid bilayer more than once

Single-pass transmembrane protein

Membrane protein in which the polypeptide chain crosses the lipid bilayer only once.

Transmembrane protein

Membrane protein that extends through the lipid bilayer, with part of its mass on either side of the membrane.

Membrane transport protein

Membrane protein that mediates the passage of ions or molecules across a membrane, e.g. ion channels and carrier proteins

Plasma membrane

Membrane that surrounds a living cell.

Co-transport

Membrane transport process in which the transfer of one molecule depends on the simultaneous or sequential transfer of a second molecule

Carrier protein

Membrane transport protein that binds to a solute and transports it by undergoing several conformational changes https://o.quizlet.com/oAUyy6wGvlsvXYFRGUCvPg_m.jpg

Channel protein

Membrane transport protein that forms an aqueous pore through which a solute (e.g. ion) can pass

ABC transporter proteins

Membrane transport proteins that use ATP to transfer peptides/small molecules across membranes https://o.quizlet.com/4X3eE19WisPMDnqPoeGMwg_m.jpg

Organelle

Membrane-Enclosed compartment in a eukaryotic cell that has a distinct structure, macromolecular composition, and function (e.g. nucleus, mitochondrion, chloroplast, Golgi apparatus)

Protein translocator

Membrane-bound protein that mediates the transport of another protein across an organelle membrane.

Fas protein

Membrane-bound receptor that initiates apoptosis in the receptor-bearing cell after binding to its ligand

Mitochondrion

Membrane-bounded organelle about the size of a bacterium that carried out oxidative phosphorylation and produces most of the ATP in eukaryotic cells

Endosome

Membrane-bounded organelle in animal cells that carries newly ingested materials by endocytosis and passes many of them on to lysosomes for degradation

Lysosome

Membrane-bounded organelle in eukaryotic cells containing digestive enzymes which are typically most active at the acid pH found in the lumen of this organelle

Golgi apparatus

Membrane-bounded organelle in eukaryotic cells in which proteins and lipids transferred from the ER are modified and sorted. Site of synthesis of cell wall polysaccharides in plants and extracellular matrix glycosaminoglycans in animal cells

Secretory vesicle

Membrane-bounded organelle in which molecules destined for secretion are stored prior to release. Sometimes called secretory granule because darkly staining contents make the organelle visible as a small solid object.

Polyribosome (polysome)

Messenger RNA molecule to which are attached a number of ribosomes engaged in protein synthesis.

Citric acid cycle

Metabolic pathway found in aerobic organisms. Oxidizes acetyl groups derived from food molecules to CO2 and H2O. Occurs in mitochondria

Micron

Micrometer. Unit of measurement often applied to cells and organelles. Equal to 10^-6 m

Fluorescence microscope

Microscope designed to view material stained with fluorescent dyes. Similar to a light microscope but the illuminating light is passed through one set of filters before the specimen, to select those wavelengths that excite the dye and through another set of filters before it reaches the eye, to select only those wavelengths emitted when the dye fluoresces

Growth cone

Migrating motile tip of a growing nerve cell axon or dendrite https://o.quizlet.com/Fm6WoFFL-MXmjk6fcvxVmg_m.png

Mitochondrial precursor protein

Mitochondrial protein encoded by a nuclear gene, synthesized in the cytosol, and subsequently transported into mitochondria

MAP-kinase

Mitogen activated protein kinase that performs a crucial step in relaying signals fro the plasma membrane to the nucleus. Turned on by a wide range of proliferation or differentiation-inducing signals

Molecular weight

Molecular mass of a molecule. The sum of the mass of each atom multiplied by the number of atoms of each particular element that makes up the molecule

Nucleoside

Molecule composed of a purine or pyrimidine base covalently linked to a ribose or deoxyribose sugar

AMP

Molecule composed of an adenine, ribose and one phosphate group. One of the four nucleotides in an RNA molecule.

Triacylglycerol (Triglyceride)

Molecule composed of three fatty acids esterified to glycerol. The main constituent of fat droplets in animal tissues (where the fatty acids are saturated) and of vegetable oils (where the fatty acids are mainly unsaturated).

Proteoglycan

Molecule consisting of one or more glycosaminoglycan (GAG) chains attached to a core protein.

Amide

Molecule containing a carbonyl group linked to an amine

Amine

Molecule containing nitrogen and hydrogen. + in water

Ester

Molecule formed by condensation reaction of an alcohol group with an acidic group. Phosphate groups usually form esters when linked to a second molecule https://o.quizlet.com/MgGM0nY0ce4BqTQNNKVWOA_m.jpg

Substrate

Molecule on which an enzyme acts.

Tracer

Molecule or atom that has been labeled either chemically or radioactively so that it can be followed in a biochemical process or readily located in a cell or tissue.

Macromolecule

Molecule such as a protein, nucleic acid, or polysaccharide with a molecular mass greater than a few 1000 daltons

Electron carrier

Molecule such as cytochrome c, which transfers an electron from a donor molecule to an acceptor molecule

Fluorescent dye

Molecule that absorbs light at one wavelength and responds by emitting light at another wavelength. The emitted light is of longer wavelength (and hence lower energy) that the light absorbed

Aromatic

Molecule that contains a carbon ring and single and double bonds

Electron donor

Molecule that easily gives up an electron, becoming oxidized in the process

Antigen

Molecule that provokes an immune response

Isomers

Molecules that are formed by the same atoms in the same chemical linkage but with different three dimensional conformation

Ran

Monomeric GTPase present in both cytosol and nucleus that is required for the active transport of macromolecules into and out of the nucleus through nuclear pore complexes. Hydrolysis of GTP and GDP is thought to provide the energy required for this transport.

ARF protein

Monomeric GTPase responsible for regulating COPI and clathrin coat assembly at Golgi membranes https://o.quizlet.com/i/GyMQYcugL04uecqwMBLDvw_m.jpg

Myoblast

Mononucleated, undifferentiated muscle precursor cell. A skeletal muscle cell is formed by the fusion of multiple myoblasts. Myo = muscle, blast = immature