Anatomy and Physiology
thinkerbell
CHAPTER7.pptxUNIT 1 CHAPTER 7
CELL GROWTH AND DEVELOPMENT
GROWTH AND REPRODUCTION OF CELLS
Cell growth: Depends on using genetic information in DNA to make the structural and functional proteins needed for cell survival
Cell reproduction: ensures that genetic information is passed from one generation to the next.
GROWTH AND REPRODUCTION OF CELLS (cont.)
Cell growth: a newly formed cell produces a variety of molecules and other structures necessary for growth by using the information contained in the genes of DNA molecules; this stage is known as interphase
Production of cytoplasm: more cell material is made, including growth and/or replication of organelles and plasma membrane; a largely anabolic process
LIFE CYCLE OF THE CELL.
The Cell Cycle: 2 major phases Interphase and Mitosis
Mitosis
Division of somatic cells (non-reproductive cells)
A single cell divides into two identical daughter cells.
Daughter cells have same number of chromosomes as does parent cell.
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Mitosis
Divided into 4 phases
Prophase
Metaphase
Anaphase
Telophase
Followed with Cytokinesis
Depending on cell- may last a few minutes to several days
Prophase
1st and longest phase
of mitosis
Events
Chromosomes become visible.
Centrioles separate and move to opposite sides of the cell.
Chromosomes become attached to fibers in the spindle at the centromere.
Chromosomes coil more tightly.
Nucleolus disappears .
Nuclear envelope breaks down.
Metaphase
Often lasts only a few minutes
Events
Chromosomes line up across the center of the cell.
Microtubules connect the centromere of each chromosome to the two poles of the spindle.
Anaphase
Centromeres split
Sister chromatids separate and move to opposite poles
Anaphase ends when chromosomes stop moving.
Telophase
Chromosomes begin to disperse into a chromatin.
Nuclear envelope re-forms around each cluster of chromosomes.
Spindle begins to break apart.
Nucleolus becomes visible.
Cytokinesis
Animal cells:
Cell membrane is drawn inward until the cytoplasm is pinched into 2 nearly equal parts
Result? 2 new identical cells
The Process of Cell Division
Two main stages of cell division:
Mitosis: nucleus divides, produces 2 nuclei identical to parent cell and each other
Cytokinesis: cytoplasm divides, produces 2 cells
The CELL CYCLE
3 Parts
Interphase
Mitosis - few minutes to several days
Cytokinesis
Mitosis
4 sub-phases:
1st – Prophase
2nd – Metaphase
3rd – Anaphase
4th – Telophase
followed by
Cytokinesis
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Image: Mitosis diagram, Marek Kultys
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I Peed on the MAT.
- A single germ cell divides into four unique daughter cells.
Daughter cells have half the # of chromosomes as parent cell, so they are considered haploid.
Image: Overview of Meiosis, National Institutes of Health
What is cell division of gametes called?
Meiosis
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
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Diploid organisms receive one of each type of chromosome from female parent (maternal chromosomes) and one of each type of chromosome from male parent (paternal chromosomes)
Refers to the number of sets of chromosomes in cells.
● Haploid – one copy of each chromosome
– designated as “n”, the number of chromosomes in one “set”
– gametes
● Diploid – two sets of chromosomes (two of each chromosome)
– designated as “2n”
– somatic cells
Genetics Terminology: Ploidy
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
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Meiosis - Sex Cell (Gamete) Formation
In meiosis, there
are 2 divisions
of the nucleus:
meiosis I
&
meiosis II
Image: Overview of Meiosis, National Institutes of Health
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
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Image: Meiosis diagram, Marek Kultys
From the Virtual Cell Biology Classroom on ScienceProfOnline.com
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