Genetic definintion Flashcards
Amino Acid
The chemical building block of proteins. During translation, different amino acids are strung together to form a chain that folds into a protein.
Nucleobases (Nucleotide in FR)
The four “letters” of the genetic code, A, C, T, and G, are chemical groups called bases or nucleobases. A= adenine, C = cytosine, T = thymine, and G = guanine. Instead of thymine, RNA contains a base called uracil (U).
Chromosome
The compact structure into which a cell’s DNA is organized, held together by proteins. The genomes of different organisms are arranged into varying numbers of chromosomes. Human cells have 23 pairs.
DNA
DNA: Abbreviation of deoxyribonucleic acid, the molecule that encodes the information needed for a cell to function or a virus to replicate. Forms a double-helix shape that resembles a twisted ladder, similar to a zipper. Bases, abbreviated as A, C, T, and G, are found on each side of the ladder, or strand, which run in opposite directions. The bases have an attraction for each other,
making A stick to T and C stick to G. The sequence of these letters is called the genetic code.
Gene
GENE: A segment of DNA that encodes the information used to make a protein. Each gene is a set of instructions for making a particular molecular machine that helps a cell, organism, or virus function.
Genome
GENOME: The entire DNA sequence of an organism or virus. The genome is essentially a huge set of instructions for making individual parts of a cell and directing how everything should run.
Histones
HISTONES: The proteins that form the core of DNA packaging in the chromosome and the reason three feet of DNA can fit inside a cell. DNA wraps around each histone almost two times, like beads on a string. The packaging of histones is controlled by enzymes such as the sirtuins that add and subtract chemical groups. Tight packaging forms “silent” heterochromatin, while loose packaging forms open euchromatin, where genes are turned on.
Mitochondria
Often called the cell’s powerhouse, mitochondria break down nutrients to create energy in a process called cellular respiration. They contain their own circular genome.
NAD
NAD: Nicotinamide adenine nucleotide, a chemical used for more than five hundred chemical reactions and for sirtuins to remove acetyl groups of other proteins such as histones to turn genes off or give them cell-protective functions. A healthy diet and exercise raise NAD levels. The “+” sign you sometimes see, as in NAD+, indicates that it is not carrying a hydrogen atom.
Protein
PROTEIN: A string of amino acids folded into a three-dimensional structure. Each protein is specialized to perform a specific role to help cells grow, divide, and function. Proteins are one of the four macromolecules that make up all living things (proteins, lipids, carbohydrates, and nucleic acids).
Stem cells
STEM CELLS: Cells with the potential to turn into a specialized type of cell or divide to make more stem cells. Most cells in your body are differentiated; that is, their fate has already been decided and they cannot morph into a different kind of cell. For example, a cell in your brain cannot suddenly transform into a skin cell. Adult stem cells replenish the body as it becomes damaged over time.
Telomeres
TELOMERES/TELOMERE LOSS: A telomere is a cap that protects the end of the chromosome from attrition, analogous to the aglet at the end of a shoelace or a
burned end of a rope to stop it fraying. As we age, telomeres erode to the point where the cell reaches the Hayflick limit. This is when the cell regards the
telomere as a DNA break, stops dividing, and becomes senescent.
