CYTOGEN

• Chromosomes have two arms, one short (p) arm and one long (q) arm.
• The centromere is the region where sister chromatids are attached to spindle fibers during cell division.
• The centromere is the point where sister chromatids are attached during cell division.
• A karyotype is a visual representation of all the chromosomes in a set.
• elucidated the molecular structure of DNA in 1953 using X-ray and proposed the double helix?

  James Watson and Francis Crick
• a twisted, spiral ladder structure consisting of two long chains wound around each other and held together by hydrogen bonds?

  Helix
• composed of repeating units (nucleotide) - adenine (A), guanine (G), cytosine (C), or thymine (T)?

  DNA
• purines with a double-ring structure?

  Adenine and Guanine
• smaller pyrimidine molecules with a single ring structure?

  Cytosine and Thymine
• form the backbone, or outer structure of the helix?

  Sugar and Phosphate groups
• fifth (5') carbon of one deoxyribose molecule and the third (3') carbon of the next deoxyribose are joined?

  Covalent phosphate linkage
• holds the antiparallel strands of DNA together?

  Nitrogenous base pairs
• Two (2) link the adenine and thymine pairs, - Three (3) link the guanine and cytosine pairs?

  Hydrogen Bonds
• The process of DNA synthesis differs for the two strands of DNA because of its antiparallel structure?

  DNA SYNTHESIS
• synthesis of a new molecule of DNA?

  Replication
• first step of the process involves breakage of the hydrogen bonds that hold the DNA strands together?

  Replication
• binding proteins work to separate the strands and keep the DNA exposed at many points along the length of the helix during replication?

  DNA helicases and single-stranded
• Active region of separation is a Y-shaped structure - Originate at structures called replication bubbles?

  Replication Fork
• DNA sequences?

  Replication origins
• Formation of small segments of nucleotides?

  Okazaki fragments
• each nucleotide has a ribose sugar - The pyrimidine thymine is replaced by another pyrimidine, uracil (U). - a single-stranded molecule?

  RNA (Ribonucleic Acid)
• genetic information of DNA is stored - a linear sequence of nitrogenous bases in triplets?

  Protein Code / Code
• code for specific amino acids that are subsequently linked together to form protein molecules?

  Triplets
• first step in protein synthesis?

  Transcription
• DNA is copied into a complementary piece of messenger RNA (mRNA).?

  Transcription
• controlled by the enzyme RNA polymerase?

  Transcription
• Starts by attachment of RNA polymerase to a promoter region (sequence of bases that varies from gene to gene)?

  Transcription
• segments of DNA that do not code for an mRNA product?

  Introns
• helps in the transport of mRNA molecules to the cytoplasm?

  Poly (A) tail
• serves to aid in attachment of the mRNA to the ribosome?

  Translation
• next step in protein synthesis. A chain of amino acids is synthesized. by using the newly transcribed mRNA molecule as a template, with the help of a third - ribonucleic acid, transfer RNA (tRNA)?

  Translation
• The site of protein synthesis?

  ribosomal RNA (rRNA) and protein
• three nitrogen bases on an mRNA molecule constitute?

  Codon
• 4 nitrogenous bases, there are 64 possible three-base codons. - “stop” codons signal the termination of protein synthesis?

  Codon
• Contains Transfer RNA molecules - Nucleotide triplets that are complementary to the codons on mRNA?

  Anticodons
• transfer the specific amino acids to the synthesizing protein chain?

  Transfer RNA molecules
• Amino acids are joined to this chain?

  Peptide Bonds
• consists of a single continuous molecule of DNA - complexed with histone and nonhistone proteins?

  Human Chromatin
• a single human diploid cell, if stretched out, would be approximately 2 m in length (7) and therefore must be condensed considerably to fit within the cell nucleus?

  Human Chromatin
• DNA helix itself is the first level?

  Condensation