Across
- 3. a compound which is one of the four constituent bases of nucleic acids. A pyrimidine derivative, it is paired with adenine in double-stranded DNA.
- 6. the cytoplasmic division of a cell at the end of mitosis or meiosis, bringing about the separation into two daughter cells.
- 8. is a molecule containing one atom of phosphorus covalently bound to four oxygen residues, two of which may be expressed as a hydroxyl group.
- 12. is the process by which a double-stranded DNA molecule is copied to produce two identical DNA molecules.
- 13. is an enzyme that synthesizes DNA molecules from deoxyribonucleotides, the building blocks of DNA
- 15. a type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus, typical of ordinary tissue growth.
- 16. the resting phase between successive mitotic divisions of a cell, or between the first and second divisions of meiosis.
- 18. the first stage of cell division, before metaphase, during which the chromosomes become visible as paired chromatids and the nuclear envelope disappears. The first prophase of meiosis includes the reduction division.
- 19. The cell cycle is a cycle of stages that cells pass through to allow them to divide and produce new cells.
- 20. a minute cylindrical organelle near the nucleus in animal cells, occurring in pairs and involved in the development of spindle fibers in cell division.
- 21. a compound which is one of the four constituent bases of nucleic acids. A purine derivative, it is paired with thymine in double-stranded DNA.
- 23. a compound that occurs in guano and fish scales, and is one of the four constituent bases of nucleic acids. A purine derivative, it is paired with cytosine in double-stranded DNA.
Down
- 1. a complex organic substance present in living cells, especially DNA or RNA, whose molecules consist of many nucleotides linked in a long chain.
- 2. a pair of parallel helices intertwined about a common axis, especially that in the structure of the DNA molecule.
- 3. the final phase of cell division, between anaphase and interphase, in which the chromatids or chromosomes move to opposite ends of the cell and two nuclei are formed.
- 4. a compound found in living tissue as a constituent base of nucleic acids. It is paired with guanine in double-stranded DNA.
- 5. simply a nitrogen-containing molecule that has the same chemical properties as a base.
- 7. are enzymes that bind and may even remodel nucleic acid or nucleic acid protein complexes.
- 9. the second stage of cell division, between prophase and anaphase, during which the chromosomes become attached to the spindle fibers.
- 10. a sugar derived from ribose by replacing a hydroxyl group with hydrogen.
- 11. a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.
- 14. the stage of meiotic or mitotic cell division in which the chromosomes move away from one another to opposite poles of the spindle.
- 17. a compound consisting of a nucleoside linked to a phosphate group. Nucleotides form the basic structural unit of nucleic acids such as DNA.
- 20. the material of which the chromosomes of organisms other than bacteria (i.e., eukaryotes) are composed. It consists of protein, RNA, and DNA.
- 22. deoxyribonucleic acid, a self-replicating material which is present in nearly all living organisms as the main constituent of chromosomes. It is the carrier of genetic information.