cell growth & division. limits to cell growth dna “overload”: if a cell gets to big, dna...
DESCRIPTION
Cell Size Surface Area (length x width x 6) Volume (length x width x height) Ratio of Surface Area to VolumeTRANSCRIPT
Cell Growth & Division
Limits to Cell Growth
• DNA “Overload”: if a cell gets to big, DNA cannot serve the increasing needs of the growing cell.
• Exchanging Material: If a cell gets to big, food, oxygen, water, cannot get in quick enough and wastes cannot get out quick enough.
• Ratio of Surface Area to Volume: Volume increases much more rapidly than surface area
Cell Size
Surface Area (length x width x 6)
Volume (length x width x height)Ratio of Surface Area to Volume
Ratio of Surface Area to Volume
Chromosomes
• Contain the genetic information (DNA)
• They are not visible except during cell division.
• Humans have 46• Fruit flies have 8• Carrots have 18
Sister ChromatidsCentromere
includes
is divided into is divided into
Concept Map
Cell Cycle
M phase (Mitosis)
Interphase
G1 phase S phase ProphaseG2 phase Metaphase TelophaseAnaphase
M phase
G2 phase
S phase
G1 phase
Cell Cycle
The Cell Cycle
• Interphase: the “in-between” period of growth; longest & busiest phase of the cell cycle
• During the cell cycle, a cell grows, prepares for division, and divides into 2 daughter cells, then each begin the cycle again.
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Mitosis and Cytokinesis
Interphase: Cell Growth
• G1 cells are growing, synthesizing proteins and organelles.
• S: chromosomes are replicated• G2: organelles and other molecules
required for cell division are produced
Mitosis
• It is divided into 4 phases• Prophase• Metaphase• Anaphase• Telophase
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Mitosis and Cytokinesis
Prophase
• First and longest phase.• Centrioles separate and move to opposite
sides of the nucleus.• Centrioles help to organize the spindle
fibers• Chromatin condenses into chromosomes• Nuclear envelope breaks down.
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Mitosis and Cytokinesis
Metaphase
• The chromosomes line up across the middle of the cell (at the equator).
• Each chromosome is connected to the spindle fiber by the centromere.
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Mitosis and Cytokinesis
Anaphase
• The sister chromatids separate into individual chromosomes and are moved apart to opposite poles.
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Mitosis and Cytokinesis
Telophase
• Chromosomes begin to untangle.• Two nuclear envelopes will form• Spindle begins to break down.• Nucleolus becomes visible.
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Mitosis and Cytokinesis
Cytokinesis
• The cytoplasm pinches in half. Each daughter cell has an identical set of duplicate chromosomes.
• In plants the cells do not separate but form a cell plate between the 2 nuclei and the cell wall starts to form.
Results of Cell Division
• 2 daughter cells with same number of chromosomes as the original (parent) cell.
• Ex. 24 → 2 cells each with 24• All of our body cells go through mitosis.• Mitosis is used for growth and
development, healing, & when cells die from old age.