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| A layer of sugar residues, including the polysaccharide portions of proteoglycans and oligosaccharides attached to protein or lipid molecules, on the outer surface of a cell |
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| Type of lipid molecule used to make biological membranes. Generally composed of two fat acids linked through glycerol phosphate to one of a variety of polar groups |
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| The membrane that surrounds a living cell, involved in cell communication, import and export of molecules and cell growth and motility. |
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| Two very different properties in a single molecule, water loving head, water hating tail |
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| Lipids characterized by a carbon skeleton consisting of four fused rings (EX: Cholesterol) |
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| The biomolecular sheet of mainly phospholipid molecules that forms the structural basis for all cell membranes. |
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| Properties of membranes: Fluidity |
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| Related to the fat acids saturation and sterols presence |
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| Properties of membranes: Polarity |
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| Different composition in each layer of the membrane |
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| Lipid molecule with a characteristic four-ringed steroid structure that is an important component of the plasma membranes of animal cells |
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| A protein associated with a lipid bilayer; can be either integral (transmembrane) or peripheral |
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| Functionally specialized region in a cell membrane characterized by the presence of particular proteins |
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| Membrane Transport Proteins |
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| Any protein embedded in a membrane that serves as a carrier of ions or small molecules form one side to the other |
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| Membrane protein that transports ions or molecules across a cell membrane |
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| Pressure that must be exerted on the low-solute concentration side of a semi-permeable membrane to prevent the flow of water across the membrane as a result of osmosis |
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| Transmembrane carrier protein, found in the plasma membrane of most animal cells, that pumps Na+ out of and K+ into the cell, using the energy derived from ATP hydrolysis |
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| Membrane protein that selectively allows ions such as Na+ (carried by the voltage-gated Na+ channel) to cross a membrane and is opened by changes in membrane potential. Found mainly in electrically excitable cells such as nerve and muscle. |
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| An ion channel that opens when it binds a small molecule such as a neurotransmitter |
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| Membrane protein that allows the selective entry of specific ions into a cell and is opened by mechanical force |
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| A voltage difference across a membrane due to a slight excess of positive ions on one side and excess negative ions on the other |
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| Quantitative expression that relates the equilibrium ratio of concentrations of an ion on either side of a permeable membrane to the voltage difference across the membrane |
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| Rapid, transient, self-propagating electrical signal in the plasma membrane of a cell such as a neuron or muscle. A nerve impulse. |
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| The ending of an axon from which signals are sent to adjoining cells, usually at a synapse |
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| Small membrane-enclosed sac filled with neurotransmitter that releases its contents by exocytosis at a synapse |
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| A molecule made of a nitrogen-containing ring compound linked to a five carbon sugar, which can be either ribose or deoxyribose |
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| Nucleoside with a series of one or more phosphate groups joined by an ester linkage to the sugar moiety |
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| Two nucleotides in RNA or a DNA molecule that are specifically paired by hydrogen bonds (G with C and A with T or U) |
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| Long threadlike structure composed of DNA and associated proteins that carries the genetic information of an organism. |
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| Region of DNA that controls a discrete hereditary characteristic of an organism, usually responsible for specifying a single protein or RNA molecule |
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| Structure at the ends of linear chromosomes, 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 (Greek: Telo = end) |
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| Constricted region of a mitotic chromosome that holds sister chromatids together; also the site on the DNA where the kinetochore forms and then captures microtubules from the mitotic spindle |
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| Complex of DNA, histones, and non-histone proteins found in the nucleus of a eukaryotic cell. The material of which chromosomes are made |
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| One of the two main states in which chromatin exists within an interphase cell, the other being heterochromatin |
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| Region of a chromosome that remains unusually condensed and transcriptionally inactive during interphase |
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| ATP-dependent Chromatin-remodeling complex |
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Definition
| Enzyme (typically multi-subunit) that uses the energy of ATP hydrolysis to alter histone-DNA interactions in eukaryotic chromosomes |
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| Large structure in the nucleus where ribosomal RNA is transcribed and ribosomal subunits are assembled |
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| Site on a chromosome at which DNA replication begins |
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| Y-shaped region of a replicating DNA molecule at which the two daughter strands are formed and separate. |
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| Short length of DNA produced on the lagging strand during DNA replication. Adjacent fragments are rapidly joined together by DNA ligase to form a continuous DNA strand. |
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| Enzyme that elongates telomeres, the repetitive nucleotide sequences found at the ends of eukaryotic chromosomes |
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| Genetic exchange between a pair of identical or very similar DNA sequences, typically located on a pair of homologous chromosomes. A similar process is used to repair double-stranded breaks in DNA. |
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| Nonhomologous end-joining |
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Definition
| Mechanism for repairing double-stranded breaks in DNA in which the two broken ends are brought together and rejoined without requiring sequence homology |
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| General name for short segments of DNA that can move from one location to another in the genome. Also known as mobile genetic element. |
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| Short segment of DNA that can move, sometimes through an RNA intermediate, from one location in a genome to another. They are an important source of genetic information in most genomes |
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| The process by which a gene makes its effect on a cell or organism by directing the synthesis of a protein or an RNA molecule with a characteristic activity |
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| RNA molecule that specifies the amino acid sequence of a protein. Produced by RNA splicing (in eucaryotes) from a larger RNA molecule made by RNA polymerase as a complimentary copy of DNA. |
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| The set of successive triplets in which a string of nucleotides is translated into protein. |
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| A process that uses one strand of DNA as the template to synthesize a complementary RNA sequence, sometimes termed the primary transcript, catalyzed by the enzyme RNA polymerase |
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| General transcription factors |
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Definition
| Proteins that assemble on the promoters of many eukaryotic genes near the start site of transcription and load the RNA polymerase in the correct position |
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| Process in which intron sequences are excised from RNA molecules in the nucleus during the formation of messenger RNA |
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| Noncoding region of a eukaryotic gene that is transcribed into an RNA molecule but is then excised by RNA splicing to produce mRNA |
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| Segment of a eukaryotic gene that is transcribed into RNA and expressed; dictates the amino acid sequence of part of a protein |
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| Broad term for the modifications that RNA undergoes as it reaches its mature form. For a Eukaryotic mRNA, processing typically includes capping, splicing, and polyadenylation |
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Definition
| An RNA molecule possessing catalytic properties |
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| Large assembly of RNA and protein molecules that splices Introns out of pre-mRNA in eukaryotic cells |
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| Translation initiation factors |
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Definition
| Protein that promotes the proper association of ribosomes with mRNA and is required for the initiation of protein synthesis |
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Definition
| Special tRNA that initiates ranslation. It always carries the amino acid methionine. |
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Term
| Aminoacyl-tRNA synthetases |
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Definition
| Enzyme that attaches the correct amino acid to a tRNA molecule to form an aminoacyl-tRNA |
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Definition
| Sequence of three nucleotides in a transfer RNA molecule that is complementary to the three-nucleotide codon on a messenger RNA molecule; each anticodon is matched to a specific amino acid covalently attached elsewhere on the transfer RNA molecule |
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| Enzyme such as trypsin that degrades proteins by hydrolyzing some of their peptide bonds |
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| Large protein complex in the cytosol that is responsible for degrading cytosolic proteins that have been marked for destruction by ubiquitylation or by some other means |
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