WARMUP WHY IS IT NECESSARY THAT CELLS DIVIDE

WARM-UP WHY IS IT NECESSARY THAT CELLS DIVIDE BEFORE THEY BECOME TO LARGE ? A. LARGE CELLS PLACE MORE DEMAND ON THE DNA B. LARGE CELLS HAVE MORE TROUBLE MOVING ENOUGH MATERIAL IN AND OUT OF THE CELL ACROSS THE MEMBRANE. C. LARGE CELLS ARE MORE LIKELY TO ALTER, DESTROY, OR LOSE INSTRUCTIONS FROM THE DNA. D. ALL OF THE ABOVE

THE PROCESS OF CELL DIVISION CHAPTER 10 SECTION 2 PART 1

DNA CAN BE: SPREAD OUT IN NON-DIVIDING CELLS CHROMATIN SCRUNCHED UP IN DIVIDING CELLS CHROMOSOMES

DNA in PROKARYOTES ***PROKARYOTES LACK NUCLEI AND MANY OF THE ORGANELLES FOUND IN EUKARYOTES. ***DNA IS FOUND IN CYTOPLASM

DNA IN PROKARYOTES ***HAVE ONE CHROMOSOME **CHROMOSOME IS IN A CIRCULAR FORM

DNA in EUKARYOTES (Plants & Animals) ***GENERALLY HAS MORE DNA THAN PROKARYOTES ***HAVE MULTIPLE CHROMOSOMES

DNA in EUKARYOTES (Plants & Animals) • DNA is ROD-SHAPED CHROMOSOMES • FOUND IN NUCLEUS

WHAT DO EUKARYOTES, PROKARYOTES, ALL ORGANISMS HAVE IN COMMON? ? ***THEY ALL USE DNA TO PASS ON INFORMATION

Chromosome structure Pg. 280 in book SMALL -----BIG 1) CHROMATIN/ DNA IS WOUND TIGHTLY AROUND A PROTEIN CALLED HISTONE- THIS PAIRING IS CALLED A NUCLEOSOME. 2) NUCLEOSOMES COMPACT INTO TIGHT COILS 3) COILS FORM CHROMATIDS

Chromosome structure CHROMATIDS (SISTER) • __________ 2 identical arms CENTROMERE • _________ constricted area holds chromatids together

WHY DO CELLS DO SO MUCH TO PACKAGE DNA INTO CHROMOSOMES?

***TO ENSURE EQUAL DIVISION OF DNA WHEN THE CELL DIVIDES. ***

_______ = series of events that cells go through to ensure they grow and develop properly. http: //www. cellsalive. com/mitosis. htm

CELL DIVISION in PROKARYOTES ASEX U AL REPR ODUC T ION Bacteria reproduce using _________________ RESULTS IN 2 IDENTICAL CELLS

CELL CYCLE IN EUKARYOTES INTERPHASE – non-dividing phase G 1(cell growth)- Cell grows bigger Makes new proteins and organelles DNA is spread out as chromatin

INTERPHASE… S - Synthesis (DNA Replication) *DNA is copied *At the end of the S phase there is twice the amount DNA than there was at the beginning.

G 2 -(Preparing for cell division) *Usually the shortest of the 3 phases. *Organelles and molecules that are needed for division are produced. *Grows bigger

INTERPHASE (G 1 - S - G 2) *In between divisions *Cells 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