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CHROMOSOMES 8-1

CHROMOSOMES 8-1. http://web.jjay.cuny.edu/~acarpi/NSC/12-dna.htm. DNA. Found in NUCLEUS Carries the genetic code. http://encarta.msn.com/media_461516495/Nucleus_of_a_Cell.html. NUCLEIC ACIDS are built from subunits called ____________________. Image by: Riedell. Changing the

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CHROMOSOMES 8-1

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  1. CHROMOSOMES8-1

  2. http://web.jjay.cuny.edu/~acarpi/NSC/12-dna.htm DNA Found in NUCLEUS Carries the genetic code http://encarta.msn.com/media_461516495/Nucleus_of_a_Cell.html

  3. NUCLEIC ACIDS are built from subunits called ____________________ Image by: Riedell Changing the _____________ and _______________ produces different subunits sugar nitrogen base

  4. 5 NITROGEN BASES ADENINE _____________= A _____________ = G _____________ = C ______________ = T (only in DNA) ______________= U (only in RNA) GUANINE CYTOSINE THYMINE URACIL

  5. DNA molecule forms a HELIXor “twisted ladder” A on one strand always bonds with T opposite it G on one strand always bonds with C opposite it Image from: http://evolution.berkeley.edu/evosite/evo101/images/dna_bases.gif

  6. DNA CAN BE: SPREAD OUT INNON-DIVIDING CELLS SCRUNCHED UP IN DIVIDINGCELLS

  7. PROTEINS that wrap up DNA are called __________________ http://biology.kenyon.edu/courses/biol114/Chap01/chrom_struct.html

  8. PROTEINS Proteins-Combine with DNA to make chromosomes Image from: http://employees.csbsju.edu/hjakubowski/classes/ch331/dna/chromosome.gif

  9. Proteins that control the activity of genes are called ________________ http://www.blc.arizona.edu/courses/181summer/14.html

  10. Cells turn genes on or off as needed (part of differentiation) Example: Genes for making digestive enzymes are turned off in brain cells Genes for making neurotransmitters are turned on

  11. NON-HISTONES are the “on-off” switches for genes

  12. Some cells divide frequently (some human skin cells divide once/hour) Some cells divide occasionally (liver cells divide about once/year) Some cells don’t divide once they form (nerve cells) CELL DIVISION GENES

  13. Cancer cells have lost control of their cell division genes

  14. Cancer cells • Don’t stop dividing • Like a “car with no brakes” • Can spread to new places (METASTASIS) • ______________ are substances that can damage DNA Ex: Radiation, cigarette smoke, chemicals in environment

  15. DNA in PROKARYOTES • BACTERIAL DNA is CIRCULAR • HAVE ONE CHROMOSOME • ATTACHED TO CELL MEMBRANE http://www.origin-life.gr.jp/3202/3202121/fig6.jpg

  16. DNA in EUKARYOTES(Plants & Animals) • DNA is ROD-SHAPED CHROMOSOMES • MANY PAIRS • FOUND IN NUCLEUS http://cellbio.utmb.edu/cellbio/chrom2.jpg

  17. Chromosome structure • ___________________ 2 identical arms • __________________ constricted area holds chromatids together • __________________ PAIR • 2 of each chromosome(one from mom; one from dad)

  18. HOMOLOGOUS CHROMOSOMES • SAME SIZE • SAME SHAPE • CARRY GENES for the SAME TRAITS (Don’t have to have the SAME CHOICES) http://arnica.csustan.edu/biol3020/cell_division/cell_division.htm

  19. CHROMOSOME NUMBERS • Each species has a characteristic number of chromosomes • HUMANS have 46 chromosomes (23 pairs)

  20. You can’t judge a critter by its chromosomes This critter has54 chromosomes

  21. Corn has 10 pair of chromosomes

  22. Snails have 18 pairs of chromosomes

  23. A mouse has 40 chromosomes

  24. CHROMOSOME NUMBER DOESN’T CORRESPOND TO SIZE OF ORGANISM Big animals DON’T have more chromosomes than small animals! http://www.ocean.udel.edu/extreme2004/genomics/images/chromosomes.gif

  25. Chromosomes that determine the sex of an organism = _________________________ • All other chromosomes = _________________ Humans have two sex chromosomes And _____ autosomes

  26. A _____________is a picture of an organism’s chromosomes

  27. A KARYOTYPE can tell the sex of an organism In humans XY is a male

  28. In humans XX is a female

  29. Guess who? XY

  30. Karyotypes can also show some genetic problems http://members.tripod.com/~yenial/chromosome.html

  31. Eric has Down’s Syndrome 1 in 750 births Has extra #21 chromosome Mental retardation

  32. DIPLOID & HAPLOID Some cells have 2 copies of each chromosome = _______________ (one from mom; one from dad) • All BODY cells are diploid Image from: http://www.ncu.edu.tw/~ls/graph/faculty_pictures/whole_time/SLC/SLC_lab-1.jpg

  33. DIPLOID & HAPLOID Some cells have only one copy of each chromosome = ____________________ All sperm and egg cells are haploid

  34. http://www.angelbabygifts.com/ EGG + SPERM  If egg and sperm had same number of chromosomes as other body cells …. baby would have too many chromosomes!

  35. CELL DIVISION8-2 Mitosis and Meiosis

  36. CELL DIVISION in PROKARYOTES Bacteria reproduce using __________________ • DNA is copied • Cell wall forms • Cell splits into two • new cells http://www.tnau.ac.in/notesbscag/agm/UGMicro/AGM151_201/theory_files/image156.jpg

  37. CELL DIVISION IN EUKARYOTES __________ OR __________

  38. MITOSIS • Makes ____ cells identical to parent cell • Makes _____ cells • Makes _______ cells • Used to _____________& ____________________________________

  39. MEIOSIS • Makes ____ cells with different DNA • Makes _____ cells • Makes ____________ • Used ______________

  40. CELL CYCLE G0

  41. CELL CYCLE cells alive cell cycle

  42. CELL CYCLE INTERPHASE – non dividing phase G1- Grow bigger Cell is “doing its job” DNA is spread out as chromatin S - Synthesis (copy DNA) G2- Grow bigger, make organelles & molecules needed for cell division

  43. CELL CYCLE MITOSIS – Cell division Prophase Metaphase Anaphase Telophase Cytokinesis G0 – cell stops dividing (Ex: nerve cell)

  44. In between divisionsCells are in this phase most of the time Can see nucleus DNA spread out as chromatin Can’t see chromosomes DNA gets copied Cell gets ready to divide INTERPHASE (G1 - S - G2)

  45. PROPHASE 1st dividing phase DNA scrunches into chromosomes Nuclear membrane & nucleolus disappear Centrosomes containing centrioles appear & move to poles Spindle fibers form & attach chromosomes

  46. Chromosomes line up in ___________ METAPHASE

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