Unit 6 Review 30 Scantron Questions Vocabulary Matching True or False Multiple Choice

- Controls cell functions What does DNA stand for? Deoxyribonucleic Acid What is the function of DNA? - Stores genetic (hereditary) information - Controls cell functions 3. Who id’d DNA structure? Watson & Crick in 1953 4. Three parts of nucleotide? Phosphate, Deosyribose (sugar), Nitrogen base Nitrogen base is different for each nucleotide (different shapes) 5. Pyrimidines: Single ring shape, Thymine and Cytosine 6. Purine: Double ring shape, Adenine and Guanine

7. Complementary Base Pairs - The two nitrogen bases that bond together - Purine always bonds with a pyrimidine - Adenine pairs with Thymine, Guanine pairs with Cytosine 8. What is the structure of DNA? - Structure - Double helix, two stands of nucleotides connected - Backbone - sugar and phosphate - Rungs (sticks out into center of molecule) - nitrogen-base The order of bases is the genetic code, order codes for a specific gene (protein) 9. Parts of the Cell Theory All living organisms are made up of one or more cells Cells are the basic unit of structure and function in living organisms All cells come from the division of pre-existing cells

10. Cell Division – process where a cell splits (divides) into two cells 11. DNA Replication Helicase (enzyme) breaks apart bonds between base pairs. This separates the left and right strands of the DNA molecule DNA polymerase (enzyme) adds complementary base pairs to each separated strand. Makes two new molecules of DNA 12. Can enzymes make mistakes – YES! Mutation – change in the order of nucleotides in a molecule of DNA Most common mutations: Substitution – wrong nucleotide added Addition – extra nucleotide(s) added Deletion – nucleotide(s) removed

14. Prokaryotic Cell Division: - Binary Fission (DNA copied, Cell grows, Cytokinesis) 15. Eukaryotic Cell Division: - Mitosis or Meiosis then Cytokinesis 16. Main parts of the cell cycle: - Interphase (G1, S, G2), Division (M phase & Cytokinesis) 17. Interphase: - G1 (time gap 1)- cell grows & performs daily cellular activities S Phase (synthesis) - DNA replication, all DNA is copied (identical DNA copies (chromatids) are held together at a centromere G2 (time gap 2) - cell grows, gets ready to divide, duplicates organelles

18. DNA transform into a chromosome? How does this happen? Prophae DNA coils around proteins (histones) during Prophase, this structure is then called a chromosome Chromosomes (in X shape) are actually two identical strands of DNA (sister chromatids) held together by a centromere 19. when does the nucleus disappear?  Prophase Reappear? Telophase 20. How many times does the cell divide in mitosis? Once  How many cells are formed? Two Diploids How many chromosomes (human cells)? 46 chromosomes

21. What happens during prophase? DNA coils up into a chromosome (sister chromatids are attached by centromere) Nucleus and nucleolus disappears Centrosomes appear and begin to form spindle fibers 22. What are spindle fibers? Microtubules (proteins) Where do they form? Around centrosomes 23. What happens during metaphase? Chromosomes (sister chromatids) line up in the middle of the cell Spindle fibers elongate and attach to the centromere of each chromosome/chromatid

24. What happens during anaphase? Spindle fibers shorten and pull on the centromere Centromere breaks and the chromosome’s chromatids are separated Chromatids are pulled to opposite ends of the cell 25. What happens during telophase? Nucleus reforms around each grouping of chromatids (2 nuclei form) Chromosome/chromatids unwind back into DNA Cell gets ready to split in the middle 26. What is cytokinesis? How is it different in plants & animals? Definition – division of the cytoplasm Animals – cell membrane splits/pinches down the middle Plants – after the cell membrane splits/pinches down the middle, the plant cell would then form cell plate in the center of the cells

27. How many times does the cell divide in meiosis? Twice, Forms Four Cells Each cell has 23 chromosomes, Cells known as Haploid/Gamete/Reproductive Cell 28. What happens in meiosis? After completing Interphase (G1, S, G2), the cell would divide once (Meiosis I). The two cells would then each divide again (Meiosis II). This produces 4 haploid cells (reproductive cells) 29. How is spermatogenesis different from oogenesis? Spermatogenesis - formation of sperm, cytoplasm divides equally within the two divisions, produces four equal sized cells Oogenesis - formation of one egg and three polar bodies, cytoplasm does not divide equally

Interphase Back to Interphase Prophase Cytokinesis Telophase Metaphase Anaphase