Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Kaplan Biochem
Biochem MCAT Flashcards
| Term | Definition |
|---|---|
| Wobble | Hypothesis describing the binding of the third nucleotide of a codon to an anticodon, which is not specific and can occur with mismatched bases. In the genetic code, the third nucleotide often plays no role in specifying an amino acid. |
| Ribozyme | An RNA molecule with enzymatic activity |
| Repressible System | An operon that requires a repressor to bind to a corepressor before binding to the operator site to stop transcription of the relevant gene; also called a negative control system. |
| Promoter Region | Portion of DNA upstream from a gene; contains the TATA box, which is the site where RNA polymerase II binds to start transcription. |
| Operon | In prokaryotes, a cluster of genes transcribed as a single mRNA that can be regulated by repressors or inducers, depending on the system. |
| Lariat | The lasso-shaped structure formed during the removal of introns in mRNA processing. |
| Intron | A portion of hnRNA that is spliced out to form mRNA; remains in the nucleus during processing. Contrast with exon. |
| Inducible System | An operon that requires an inducer to remove a repressor protein from the operator site to begin transcription of the relevant gene; also called a positive control system. |
| Heterogenous nuclear RNA (hnRNA) | Preprocessed converted to mRNA by adding a poly-A tail and 5' cap and mRNA; splicing out introns. |
| Enhancer | Portion of DNA that can be bound by transcription factors to increase transcription of a gene. |
| Degenerate | Description of an aspect of the genetic code; specifically, that more than one codon can specify a single amino acid. |
| Codon | A three-nucleotide sequence in an mRNA molecule that pairs with an appropriate tRNA anticodon during translation. |
| Activation | Conversion of a biomolecule to its active or usable form, such as activating tRNA with an amino acid or activating a fatty acid with CoA to form fatty acyl-CoA. |
| Translation | Production of a protein from an mRNA molecule. |
| Transfer RNA (tRNA) | A folded strand of RNA that contains a three nucleotide anticodon that pairs with an appropriate mRNA codon during translation and is charged with the corresponding amino acid. |
| Transcription Factors | Proteins that help RNA polymerase II locate and bind to the promoter region of DNA. |
| Transcription | Production of an mRNA molecule from a strand of DNA. |
| Template Strand | The strand of DNA that is transcribed to form mRNA; also called the antisense strand. |
| Exon | A portion of hnRNA that is spliced together with other exons to form mature mRNA. Contrast with intron. |
| TATA Box | The site of binding for RNA polymerase II during transcription; named for its high concentration of thymine and adenine bases. |
| Stop Codon | The last codon of translation (UAA, UGA, or UAG); release factor binds here, terminating translation. |
| Start Codon | The first codon in an mRNA molecule that codes for an amino acid (AUG for methionine or N-formylmethionine). |
| Spliceosome | The apparatus used for splicing out introns and bringing exons together during mRNA processing. |
| Shine-Dalgarno Sequence | The site of initiation of translation in prokaryotes. |
| Ribosomal RNA (rRNA) | The structural and enzymatic RNA found in ribosomes that takes part in translation. |
| Release Factor | The protein that binds to the stop codon during termination of translation. |
| Polycistronic | The coding pattern of prokaryotes, in which one mRNA may code for multiple proteins. Contrast with monocistronic. |
| Peptide Bond | An amide bond between the carboxyl group of one amino acid and the amino group of another amino acid. |
| Operator Site | A component of the operon in prokaryotes; a nontranscribable region of DNA that is capable of binding a repressor protein. |
| Monocistronic | The coding pattern seen in the vast majority of eukaryotic proteins in which one mRNA molecule codes for only one protein. Contrast with polycistronic. |
| Messenger RNA (mRNA) | The strand of RNA formed after transcription of DNA; moves to the cytoplasm to be translated. |
| Jacob-Monod Model | The description of the structure and function of operons in prokaryotes, in which operons have structural genes, an operator site, a promoter site, and a regulator gene. |
| Initiation | The start of translation, in which the small subunit of the ribosome binds to the mRNA molecule and the first tRNA (methionine or N-formylmethionine) is bound to the start codon (AUG). |
| Elongation | The three-step cycle repeated for each amino acid being added to a protein during translation. |
| Corepressor | A species that binds with a repressor, allowing the complex to bind to the operator region of an operon, stopping transcription of the relevant gene. |
| Coding Strand | The strand of DNA that is not used as a template during transcription; also called the sense strand. |
| Chaperones | Proteins that assist in protein folding during posttranslational processing. |
| Anticodon | A three-nucleotide sequence on a tRNA molecule that pairs with a corresponding mRNA codon during translation. |
| Amplification | Increased transcription (and translation) of a gene in response to hormones, growth factors, and other intracellular conditions. |
| Alternative splicing | The production of multiple different but related mRNA molecules from a single primary transcript of hnRNA. |
| Zwitterion | A molecule that contains charges, but is neutral overall. Most often used to describe amino acids. |
| G-Coupled Protein Receptors | A special class of membrane receptors with an associated GTP binding protein; activation of a G protein-coupled receptor involves dissociation and GTP hydrolysis. |
| Structural Proteins | Proteins that are involved in the cytoskeleton and extracellular matrix; they are generally fibrous in nature and include collagen, elastin, keratin, actin, and tubulin |
| Motor Proteins | Proteins that are involved in cell motility through interactions with structural proteins; motor proteins have ATPase activity and include myosin, kinesin, and dynein. |
| Isoelectric Focusing | A specialized method of separating proteins by their isoelectric point using electrophoresis; the gel is modified to possess a pH gradient. |
| Facilitated Diffusion | The movement of solute molecules through the cell membrane down their concentration gradient via a transport protein or channel; used for ions and large or polar molecules. |
| Electrophoresis | The process of separating compounds on the basis of size and charge using a porous gel and an electric field; protein electrophoresis generally uses polyacrylamide, while nucleic acid electrophoresis generally uses agarose. |
| Centrifugation | The process of separating components on the basis of their density and resistance to flow by spinning a sample at very high speeds; the most dense components form a solid pellet and the least dense components remain in the supernatant (liquid portion). |
| Bradford Protein Assay | A colorimetric method of determining the concentration of protein in a sample as compared to a protein standard; relies on a transition of absorption between bound and unbound Coomassie Brilliant Blue dye. |
| Termination | The end of translation, in which the ribosome finds a stop codon and release factor binds to it, allowing the peptide to be freed from the ribosome. |
| Oxidative Phosphorylation | The transfer of a phosphate group, generally to ATP, which is powered by a gradient formed by oxidation-reduction reactions; occurs in the mitochondria. |
| Flavin Adenine Dinucleotide (FAD) | An energy carrier that participates as an electron acceptor and donor in the electron transport chain. |
| Central Dogma of Molecular Biology | The major steps in the transfer of genetic information, from transcription of DNA to RNA and resultant translation of that RNA to protein. |
| Wax | A lipid with a high melting point that is composed of a very long chain alcohol and a very long chain fatty acid. |
| Vitamin | An essential organic coenzyme that assists an enzyme in carrying out its action. |
| Terpene | A class of lipids built from isoprene moieties; have carbon groups in multiples of five. |
| Sphingomyelin | A sphingophospholipid containing a sphingosine backbone and a phosphate head group. |
| Sphingolipid | A lipid containing a sphingosine or sphingoid backbone bound to fatty acid tails; includes ceramide, sphingomyelins, glycosphingolipids, and gangliosides. |
| Phospholipid | A lipid containing a phosphate and an alcohol (glycerol or sphingosine) joined to hydrophobic fatty acid tails. |
| Glycosphingolipid | A sphingolipid with a head group composed of sugars; includes cerebrosides and globosides. |
| Glycerophospholipid | A lipid containing a glycerol backbone with a phosphate group; bound by ester linkages to two fatty acids. |
| Globoside | A sphingolipid with multiple carbohydrate groups attached as a head group. |
| Ganglioside | A sphingolipid with a head group containing an oligosaccharide and one or more N-acetylneuraminic acid (NANA) molecules. |
| Surfactant | A compound that lowers surface tension by acting as a detergent or emulsifier. |
| Saponification | The reaction between a fatty acid and a strong base, resulting in a negatively charged fatty acid anion bound to a metal ion; creates soap. |
| Glycerol | A three-carbon alcohol that serves as the backbone for glycerophospholipids, sphingolipids, and triacylglycerols. |
| Ceramide | The simplest sphingolipid, with a single hydrogen as its head group. |
| Triacylglycerol | A glycerol molecule esterified to three fatty acid molecules; the most common form of fat storage within the body. |
| Micelle | A collection of fatty acid or phospholipid molecules oriented to minimize free energy through hydrophobic and hydrophilic interactions; generally a sphere with a hydrophobic core and hydrophilic exterior. |
| Fatty Acid | A monocarboxylic acid without additional substituents; fatty acids may be saturated (all single bonds) or unsaturated (contain at least one double bond); natural unsaturated fatty acids are in the cis conformation. |
| Apolipoprotein | Protein component of lipoprotein complexes. Responsible for the interactions of the resultant lipoproteins with cells and the transfer of lipid molecules between molecules. Also called apoproteins. |
| Transferase | An enzyme that catalyzes the transfer of a functional group. |
| Pancreatic Proteases | The enzymes that are primarily responsible for the digestion of proteins in the small intestine; they include trypsin, chymotrypsin, and carboxypeptidases A and B, all of which are secreted as zymogens. |
| Nontemplate synthesis | The method of de novo synthesis of lipids and carbohydrates that relies on gene expression and enzyme specificity rather than the genetic template of DNA or RNA. |
Created by:
geodudeserg
Popular MCAT sets