Bio 2
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
The Cell Cycle<br />
The Cell Cycle<br />
Mitosis<br />
Meiosis<br />
* Property of STI<br />
I0018<br />
* Property of STI<br />
I0018<br />
1 __________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
The Cell Cycle<br />
A salamander can regenerate a lost<br />
tail or limb through cell-division!<br />
2 _________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
The Cell Cycle<br />
Regeneration also occurs in humans…<br />
wounds<br />
growing<br />
* Property of STI<br />
I0018<br />
3 __________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
* Property of STI<br />
I0018<br />
Image source: Google image search<br />
4 _________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________
The Cell Cycle<br />
The Cell Cycle<br />
The Cell Cycle<br />
• Series of events that take place in a cell leading to<br />
its division and duplication<br />
• In cells without a nucleus (prokaryotic), the cell<br />
cycle occurs via a process termed binary fission<br />
• In cells with a nucleus (eukaryotes), the cell cycle<br />
can be divided in two periods: interphase and the<br />
mitotic phase<br />
The Cell Cycle<br />
• Vital process by which a single-celled fertilized<br />
egg develops into a mature organism<br />
• Process by which hair, skin, blood cells, and some<br />
internal organs are renewed<br />
* Property of STI<br />
I0018<br />
* Property of STI<br />
I0018<br />
5 __________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
The Cell Cycle<br />
6 _________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
The Cell Cycle<br />
Four Phases of Cell Cycle<br />
• G1 Phase<br />
• S Phase / Synthesis<br />
• G2 Phase<br />
• M Phase / Mitosis<br />
After cell division, each of the daughter cells begins the<br />
interphase of a new cycle<br />
* Property of STI<br />
I0018<br />
* Property of STI<br />
I0018<br />
7 __________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
8 _________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________
Mitosis<br />
The Cell Cycle<br />
• The process by which a eukaryotic cell separates the<br />
chromosomes in its cell nucleus into two identical<br />
sets in two nuclei<br />
• Followed immediately by cytokinesis, which divides<br />
the nuclei, cytoplasm, organelles and cell membrane<br />
into two cells containing roughly equal shares of<br />
these cellular components<br />
• Mitosis and cytokinesis together define the mitotic<br />
(M) phase of the cell cycle - the division of the<br />
mother cell into two daughter cells, genetically<br />
identical to each other and to their parent cell<br />
Mitosis<br />
Stages of Mitosis<br />
* Property of STI<br />
I0018<br />
* Property of STI<br />
I0018<br />
Image source: Google image search<br />
9 __________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
Stages of Mitosis<br />
10 ________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
Stages of Mitosis<br />
•The phase of the cell cycle in which the<br />
cell spends the majority of its time and<br />
performs the majority of its purposes<br />
including preparation for cell division<br />
Interphase<br />
• The genetic material condenses into a<br />
highly ordered structure called a<br />
chromosome<br />
Prophase<br />
• In preparation for cell division, it<br />
increases its size and makes a copy of its<br />
DNA, which is made during the S phase<br />
• Considered to be the 'living' phase of<br />
the cell<br />
• Since the genetic material has been<br />
duplicated, there are two identical copies<br />
of each chromosome in the cell<br />
• Identical chromosomes (called sister<br />
chromosomes) are attached to each other<br />
at a DNA element present on every<br />
chromosome called the centromere<br />
• A cohesin acts as a glue joining two sister<br />
chromosomes along their lengths<br />
* Property of STI<br />
I0018<br />
Image source: Google image search<br />
* Property of STI<br />
I0018<br />
Image source: Google image search<br />
11 _________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
12 ________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________
EKC1<br />
Stages of Mitosis<br />
Stages of Mitosis<br />
• Kinetochores begin to form at the<br />
centromeres<br />
Prometaphase<br />
• Microtubules begin to line up in the<br />
middle of the cell<br />
Metaphase<br />
• Akintetochores contains a molecular<br />
motor that uses energy from ATP<br />
molecules to move a chromatid along a<br />
microtubule<br />
• Two kinetochores form on each<br />
chromosome - one for each chromatid<br />
• When the spindle grows to sufficient<br />
length, the microtubules begin searching<br />
for kinetochores to attach to<br />
• Proper segregation requires that<br />
every kinetochore be attached to a<br />
microtubule before separation begins<br />
• Unattached kinetochores control this<br />
process by generating a signal - the<br />
mitotic spindle checkpoint - that tells<br />
the cell to wait before proceeding to<br />
anaphase<br />
* Property of STI<br />
I0018<br />
Image source: Google image search<br />
13 _________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
* Property of STI<br />
I0018<br />
Image source: Google image search<br />
14 ________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
Stages of Mitosis<br />
Stages of Mitosis<br />
• Early anaphase - the proteins that bind<br />
the sister chromatids together are<br />
cloven and pulled apart by the<br />
microtubules towards the respective<br />
centrioles to which they are attached<br />
Anaphase<br />
•Daughter chromosomes arrive at poles<br />
• The nuclear membrane reforms around<br />
the genetic material and the<br />
chromosomes are unfolded back into<br />
chromatin<br />
Telophase<br />
• Late anaphase - the spindle axis<br />
elongates, driving the centrioles apart<br />
to opposite ends of the cell<br />
• At the end of anaphase, the cell has<br />
succeeded in separating identical<br />
copies of the genetic material into two<br />
distinct populations<br />
•This is often followed by cytokinesis or<br />
cleavage, where the cellular membrane<br />
pinches off between the two newly<br />
separated nuclei, to form two new<br />
daughter cells<br />
•At this point, each new nucleus contains<br />
one copy of each chromosome<br />
* Property of STI<br />
I0018<br />
Image source: Google image search<br />
15 _________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
* Property of STI<br />
I0018<br />
Image source: Google image search<br />
16 ________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________
Stages of Mitosis<br />
Mitosis<br />
Significance of Mitosis<br />
Cytokinesis<br />
• The last stage of mitosis<br />
• The cell's cytoplasm divides<br />
in half forming distinct cells<br />
• Development and Growth<br />
• Cell Replacement<br />
• Regeneration<br />
• Asexual Reproduction<br />
* Property of STI<br />
I0018<br />
Image source: Google image search<br />
17 _________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
* Property of STI<br />
I0018<br />
Image source: Google image search<br />
18 ________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
The Cell Division<br />
• The process by which a parent cell<br />
divides into two or more daughter<br />
cells<br />
• Usually occurs as part of a larger cell<br />
cycle<br />
• Has 2 types:<br />
I. Vegetative division (mitosis)<br />
II. Reductive division (meiosis)<br />
What is meiosis?<br />
• Greek word for “decrease”<br />
Meiosis<br />
• Forms the basis for sexual reproduction<br />
• Form of nuclear division by which a diploid parent<br />
produces four haploid daughter cells<br />
• Includes the two stages of nuclear division (meiosis I and<br />
II), each usually accompanied by cell division<br />
• Most animals and plants are normally diploid, and use<br />
meiosis to produce sexual gametes, which fuse to form<br />
zygotes that develop into new organisms<br />
* Property of STI<br />
I0018<br />
Image source: Google image search<br />
19 _________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
* Property of STI<br />
I0018<br />
20 ________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________
Meiosis<br />
Significance of Meiosis<br />
• Facilitates stable sexual<br />
reproduction<br />
• Produces genetic variety in<br />
gametes that propagate to<br />
offspring<br />
Image source: http://kenpitts.net/hbio/8cell_repro/meiosis2.gif<br />
• Allows a species to maintain<br />
stability under environmental<br />
changes<br />
* Property of STI<br />
I0018<br />
21 _________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
____________________________<br />
* Property of STI<br />
I0018<br />
Image source: Google image search<br />
22 ________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________<br />
___________________________
Change language