A. Chromosomes -structures in a cell which contain the __________
information which is passed from one generation of cells to the next.
For more information, click here.
- the word chromosome means "___________ ___________"
because when you dye a cell during cell division, you can see them (but
usually not at other times).
-in prokaryotes, DNA is in the form of _________________ molecules.
-in eukaryotes, DNA is in _________ ___________. Cells of each organism
contain specific numbers of chromosomes. Humans have ____ chromosomes.
1. Composition of Chromatin
-chromatin makes up _________________.
-between cell divisions, chromatin has the following structure:
-when cell division starts, all the chromatin ______________ (and therefore becomes visible with dye)
-What makes up chromatin? ____________ and _____________
-in 1973, Don Olins, Ada Olins, and Christopher Woodcock fournd that the chromosome's DNA was coiled around special proteins called ____________. These complexes were called ______________.
- after replication (before cell division) the chromosome is composed of two _____________ (identical parts) attached at the _____________.
B. The Cell Cycle
-goes from the beginning of one ___________ to the beginning of the next ____________.
-includes ____________, prepares for ____________, divides into two cells and cycle starts over.
-the cell cycle includes:
1. _____________ (a period of active division called the M phase); during this phase, the nucleus divides into _______ nuclei.
2. _____________ (a period of nondivision) which is divided into three parts (see below).
C. Interphase
is divided into three parts:
G1 (gap 1) -
S (DNA synthesis) -
G2 (gap 2) -
D. Mitosis
is divided into four phases: (remember P-M-A-T!!)
1. Prophase: first phase in mitosis, ___________ phase in mitosis.
-chromosomes appear because they are _____________. You can see ____________ held together by the ______________.
-the _____________ (two tiny structures in the cytoplasm near the nucleus) ____________ and stop on opposite sides of the __________.
-centrioles contain a microtubule protein called ___________.
-chromosomes attach to fibers in the ___________ near the chromatid's centromere. The spindle develops from the _______________.
-chromosomes coil even tighter, the nucleolus ____________, and the nuclear envelope _________________.
Plant Animal
2. Metaphase: second phase in mitosis, _____________ phase.
- chromosomes ____________ across the center of the cell (the "equator").
-microtubules connect the _____________ of each chromosome to poles of the _____________.
Plant Animal
3. Anaphase: third phase of mitosis
-______________ joining sister chromatids _________, separating the chromatids.
-chromosomes are pulled to the _________ of the cell.
-anaphase ends when the chromosomes ___________ moving.
Plant Animal
4. Telophase: fourth phase of mitosis
- chromosomes begin to ____________
Plant Animal
A review of the stages of mitosis
Click here f'or more pictures of mitosis.
E. Cytokinesis
-in animal cells, the ________ _____________ pinches inward like a belt tightening. You end up with _______ cells, each with its own nucleus and cytoplasmic organelles.
- in plant cells, a _________ ____________ forms down the middle of
the cell, becomes the cell membrane and eventually the ________ _______ forms.
