Download Section 8.2 Summary – pages 201

Section Objectives
• Sequence the events of the cell cycle.
• Relate the function of a cell to its
organization in tissues, organs, and organ
systems.
Cell Size Limitations
• The cells that make up a multicellular
organism come in a wide variety of sizes and
shapes.
• Considering this wide range of cells sizes,
why then can’t most organisms be just one
giant cell?
Diffusion limits cell size
• Although diffusion is a fast and efficient
process over short distances,
____________________________________
____________________________________
___________________________________.
• Because of the slow rate of diffusion,
organisms can’t be just ________________.
DNA limits cell size
• The cell cannot survive unless there is
___________________________________
of the cell.
• In many large cells, _________________
_____________________is present.
• ____________________________________
ensure that cell activities are carried out
quickly and efficiently.
Surface area-to-volume ratio
4 mm
1 mm
2 mm
1 mm
1 mm
mm2
Surface area = 6
Volume = 1 mm3
4 mm
2 mm
2 mm
4 mm
Surface area = 24 mm2
Volume = 8 mm3
• As a __________increases, its
______________increases much faster than
its surface area.
Surface area-to-volume ratio
4 mm
1 mm
2 mm
1 mm
1 mm
mm2
Surface area = 6
Volume = 1 mm3
4 mm
2 mm
2 mm
4 mm
Surface area = 24 mm2
Volume = 8 mm3
• If cell size________, the cell would require
____times more _________and would have
____ times more ____________ to excrete.
Surface area-to-volume ratio
4 mm
1 mm
2 mm
1 mm
1 mm
mm2
Surface area = 6
Volume = 1 mm3
4 mm
2 mm
2 mm
4 mm
Surface area = 24 mm2
Volume = 8 mm3
• The___________________, however, would
increase by a factor of only_________.
Surface area-to-volume ratio
4 mm
1 mm
2 mm
1 mm
1 mm
mm2
Surface area = 6
Volume = 1 mm3
4 mm
2 mm
2 mm
4 mm
Surface area = 24 mm2
Volume = 8 mm3
• The cell would either ______________or
be ___________________from the buildup
of waste products.
Cell Reproduction
• Cell division is the process by which
____________________________________
___________________________________.
• Cell division results in _________________
____________________________________
___________________________________.
The discovery of chromosomes
• Structures, which_____________________
• ___________________________________,
are called chromosomes.
• Chromosomes are the _________________
• ____________________________________
___________________________________.
• Accurate transmission of chromosomes
during cell division is__________________.
The structure of eukaryotic chromosomes
Centromere
Sister
chromatids
Supercoil within
chromosome
Chromosome
Continued coiling
within supercoil
Histone H1
Nucleosome
DNA
The Cell Cycle
• The cell cycle is ______________________
• ___________________________________.
• The __________
of a cell’s life is
spent in the
_______________
period known as
______________.
Interphase
The Cell Cycle
• Following interphase, a cell enters its period
of ______________________called mitosis.
• Following
mitosis,______
_____________
____________,
separating the
two daughter
Mitosis
cells.
Interphase: A Busy Time
• Interphase, the busiest phase of the cell
cycle, is_____________________________.
Interphase
DNA synthesis
and replication
Rapid
growth
and
metabolic
activity
Centrioles replicate;
cell prepares for
division
Interphase: A Busy Time
• During the first part, the________________
___________________________________.
Interphase
Rapid
growth
and
metabolic
activity
Interphase: A Busy Time
• In the next part of interphase,____________
___________________________________.
Interphase
DNA synthesis
and replication
Interphase: A Busy Time
• After the chromosomes have been
duplicated, the cell enters another shorter
growth period in which_________________
____________________________________
____________________________________
___________________________________.
Interphase
Centrioles replicate; cell
prepares for division
The Phases of Mitosis
• The four phases of mitosis are:
• __________________________
• __________________________
• __________________________
• __________________________
Prophase: The first phase of mitosis
• During prophase,______________________
___________________________________.
Spindle fibers
Disappearing
nuclear envelope
Doubled
chromosome
Prophase: The first phase of mitosis
• The ______________________________
• ____________are called sister chromatids.
Sister
chromatids
Prophase: The first phase of mitosis
• Sister chromatids are ______________by
a structure called a centromere, which
plays a role in chromosome ___________
during mitosis.
Centromere
Metaphase: The second stage of mitosis
• During metaphase, the chromosomes______
____________________________________
___________________________________.
Centromere
Sister
chromatids
Anaphase: The third phase of mitosis
• During anaphase, the ________________and
the sister chromatids are ______________to
opposite poles of the cell.
Telophase: The fourth phase of mitosis
• During telophase, ___________________are
formed. The cells _______________as the
cell cycle proceeds into the next interphase.
Nuclear
envelope
reappears
Two daughter cells are formed
Cytokinesis
• Following telophase, the ______________
___________in a process called cytokinesis.
• Cytokinesis differs between plants and
animals.
• Toward the end of telophase in__________,
the plasma membrane ________________in
along the equator.
Cytokinesis
• Plant cells have a rigid cell wall, so the
plasma membrane ___________________in.
• A structure known as the ______________is
laid down across the cell’s equator.
• A ____________________around each cell,
and new cell walls form on each side of the
_____________until separation is complete.
Results of Mitosis
• When mitosis is complete, _________
• _______________remain as ________ cells.
• In multicellular organisms, cell growth and
reproduction result in _________________
____________________________________
to perform a specific function.
Results of Mitosis
• Tissues organize in various combinations to
form organs that _________________
__________________________within the
organism.
• ____________________________that work
together form an organ system.