Section 2 Objectives – page 201

Section Objectives

• Relate the function of a cell to its organization in tissues, organs, and organ systems.

• Sequence the events of the cell cycle.

Cell Size LimitationsCell 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 sizeDiffusion 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 sizeDNA 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 ratioSurface area-to-volume ratio

• As a __________increases, its ______________increases much faster than its surface area.

Surface area = 6 mm2 Volume = 1 mm3


1 mm 1 mm

1 mm

2 mm 2 mm

2 mm

4 mm 4 mm

4 mm



1 mm 1 mm

1 mm

2 mm 2 mm

2 mm

4 mm 4 mm

4 mm

• If cell size________, the cell would require ____times more _________and would have ____ times more ____________ to excrete.


• The___________________, however, would increase by a factor of only_________.




1 mm 1 mm

1 mm

2 mm 2 mm

2 mm

4 mm 4 mm

4 mm




1 mm 1 mm

1 mm

2 mm 2 mm

2 mm

4 mm 4 mm

4 mm

• The cell would either ______________or be ___________________from the buildup of waste products.

Cell ReproductionCell Reproduction

• Cell division is the process by which _______________________________________________________________________.

• Cell division results in ________________________________________________________________________________________.

The discovery of chromosomesThe discovery of chromosomes

• Structures, which_____________________

• ___________________________________, are called chromosomes.

• Chromosomes are the _________________

• _______________________________________________________________________.

• Accurate transmission of chromosomes during cell division is__________________.

The structure of eukaryotic chromosomesThe structure of eukaryotic chromosomes

Centromere

Chromosome

Sister chromatids

Supercoil within chromosome

Continued coiling within supercoil

Histone H1

Nucleosome

DNA

The Cell CycleThe Cell Cycle• The cell cycle is ______________________

• ___________________________________.

• The __________of a cell’s life is spent in the _______________period known as ______________. Interphase

The Cell CycleThe Cell Cycle

• Following interphase, a cell enters its period of ______________________called mitosis.

• Following mitosis,_______________________________, separating the two daughter cells.Mitosis

Interphase: A Busy TimeInterphase: A Busy Time

• Interphase, the busiest phase of the cell cycle, is_____________________________.

DNA synthesis and replication Centrioles replicate;

cell prepares for division

Rapid growth and metabolic activity

Interphase


• During the first part, the___________________________________________________.

Rapid growth

and metabolic activity

Interphase


• In the next part of interphase,_______________________________________________.

DNA synthesis and replication

Interphase


• After the chromosomes have been duplicated, the cell enters another shorter growth period in which____________________________________________________________________________________________________________________________.

Centrioles replicate; cell prepares for division

Interphase

The Phases of MitosisThe Phases of Mitosis

• The four phases of mitosis are:

• __________________________

• __________________________

• __________________________

• __________________________

Prophase: The first phase of mitosisProphase: The first phase of mitosis

• During prophase,_________________________________________________________.

Spindle fibers

Disappearing nuclear envelope

Doubled chromosome


• The ______________________________

• ____________are called sister chromatids.

Sister chromatids


• Sister chromatids are ______________by a structure called a centromere, which plays a role in chromosome ___________

during mitosis.

Centromere

Metaphase: The second stage of mitosisMetaphase: The second stage of mitosis

• During metaphase, the chromosomes_____________________________________________________________________________.

Centromere

Sister chromatids

Anaphase: The third phase of mitosisAnaphase: The third phase of mitosis

• During anaphase, the ________________and the sister chromatids are ______________to opposite poles of the cell.

Telophase: The fourth phase of mitosisTelophase: 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

CytokinesisCytokinesis

• 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.

CytokinesisCytokinesis

• 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 MitosisResults 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 MitosisResults of Mitosis

• Tissues organize in various combinations to form organs that ___________________________________________within the organism.

• ____________________________that work together form an organ system.

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Section 2 Objectives – page 201