Cell Biology/Glossary

Alpha HelixDNA forms a specific formation called a alpha helix. Amino AcidThe basic subunit of proteins. AtomOne unit of a given element. Bacteria Carbohydrate CarbonOne of the common elements found in organic matter and living things. Cell Wallfound in prokaryotic plants and it provides structural support and protection. Chloroplastsconvert light/food into usable energy. (ATP production) CholesterolFound in cell membranes, affects the rigidity of the membrane. Also a basic compound used to form man hormones. Chromatin ChromosomeA group of genes/DNA that are contiguous, a functional unit. Humans have 23 pairs chromosomes. CiliaHair-like structures. CisternaeThe flatten sacs of the Rough Endoplasmic Reticulum. CrossoverGenetics term for chromosomes literally crossing over DNA from one chromosome to another. CyanophytesOne type of prokaryote (cell without a nucleus). Cytoplasm the protoplasm outside the nucleus CytoskeletonMicrotubules, actin and intermediate filaments. This produces the support structure/shape of cells. Of course plant cells have a much more rigid shape due to the cell wall. CytosolThe 'fluid' portion of the cell, it is made up of water and many free proteins and other elements - all except the organelles. DNADeoxyribonucleic Acid, made up of 4 nucleotides: Adenine, Guanine, Thymine, and Cytosine (A,G,T,C). ElementElement is one atom of a particular substance found on the periodic table. (Things such as Carbon, Hydrogen, Oxygen, etc.) Endoplasmic Reticulum (ER)Important for protein synthesis. It is a transport network for molecules destined for specific modifications and locations. There are two types: Rough ER - has ribosomes, and tends to be more in 'sheets'. Smooth ER - Does not have ribosomes and tends to be more of a tubular network. EukaryoteA Cell with a nucleus. Flagella GeneA section of DNA molecule that produces a functional RNA molecule Genetic Material Globular Protein Glycolipids Glycoprotiens Golgi Apparatusimportant for glycosylation, secretion. Histones HydrogenA common element in organic and living organisms. Hydrophilic'likes water' (hydro = water; philic = like). Meaning that a hydrophilic molecule or portion would be attracted to water. Much like the opposite poles of a magnet pulling each other together. Hydrophobic'fears water' (hydro = water; phobic = fear). Meaning that a hydrophobic molecule or portion would be repulsed/push-away a water molecule. This would be like trying to put together the same pole of two magnets. Examples: oils, fatty acids (i.e. the 'tails' of phospholipids), cholesterol. Lipid LysosomesDigestive sacks - the main point of digestion, these are only found in animal cells. Meiosisis a type of cell division. See section on meiosis. This occurs for formation of egg/sperm cells, which in the end have 1/2 the normal number of chromosomes, only 1 copy of each chromosome. MicrometerA unit of measure in the metric system. 10^-6 meters. Microtubulesmade from tubulin, and make up centrioles,cilia, etc. MillimeterA unit of measure in the metric system. 10^-3 meters. Mitochondriaconvert foods into usable energy. (ATP production) A mitochondrion does this through aerobic respiration. They have 2 membranes, the inner membranes shapes differ between different types of cells, but they form projections called cristae. The mitochondrion is about the size of a bacteria, and it carries its own genetic material and ribosomes. MitosisThe cell division, that is found in most non-reproductive cells. NanometerA unit of measure in the metric system. 10^-9 meters. NitrogenA common element in organic and living organisms. Nucleic AcidBasic Building block for DNA. NucleolusOr densely packed portion of the Nucleus. Nucleus (only in eukaryotes) - where genetic material (DNA) is located, RNA is transcribed. Organelles(which also have membranes) in 'higher' eukaryote organisms: Osmosis The diffusion of water through a semi-permeable membrane down the water potential gradient (from areas of high water potential to areas of low water potential) OxygenA common element in organic and living organisms. PeptidoglycanThis is the main component of prokaryotic cell walls, it is made from a large protein polymer and sugar. PeroxisomesUse oxygen to carry out catabolic reactions, in both plant and animals. PhospholipidSee the section of the course on Cell Membranes and specifically phospholipids. PhosphorusA common element in organic and living organisms. Plasma membraneThe surface around the cell made up of phospholipids, proteins, cholesterol, etc.. See the section on the Cell Membrane Plasmid Plastids ProkaryoteCells without a nucleus. Protein Protoplasm the living material in the cell Pseudopodliterally means 'false foot' RNARibonucleic Acid RNApolymerase Recombination Ribosomeshalf are on the endoplasmic reticulum, the other half are 'free' in the cytosol, which is where the RNA goes for translation into proteins. SulphurA common element in organic and living organisms. tRNATransfer RNA, a 3D structure. It works with the ribosome and mRNA to form proteins (called translation). It has an 'anti-codon' which will match codons of the mRNA, and also has a amino-acid. The tRNA is a key to the having the amino acid match a specific codon on the mRNA, See the Codon Table to see how these are matched in general. There are differences in how the matches take place in mitochondria and bacteria. Vacuole Vesicle