Post on 20-Jan-2018
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The Cell Cycle &
Cell Division
Basic Understanding
• Structure – An arrangement or organization of parts to form an organ, system, or living thing.
• Characteristics – pertaining to, constituting, or indicating the character or peculiar quality of a person or thing
Basic Understanding
• Response –any behavior of a living organism that results from an external or internal stimulus.
• Stimulus - Something that can elicit or evoke a physiological response in a cell, a tissue, or an organism
• Species –composed of related individuals that resemble one another, are able to breed among themselves
Basic Understanding
• Development – the act or process of growth or progress
• Function – to perform a specified action or activity; work
• Mobility – The ability to move from place to place, job to job, or level to level.
Basic Understanding
• Extinction – a coming to an end or dying out
• Hierarchy –any organized system of things ranked one above another in successive order
Robert Hooke
• English Naturalist• Was the first to use
the term cell.• Was looking at
CORK under a compound microscope.
What is a cell?•It is the smallest unit of life that
carries out life functions
The Cell Theory
• The cell is the basic unit of structure and function (a.k.a. – life)
• All living things are made up of 1 or more cells
• Cells come from other, preexisting cells (a.k.a. – reproduction)
Francesco Redi – The Italian Doctor
• It was previously thought that maggots spontaneously grew. Redi disproved this theory.
• He took 8 jars of rotting meat and covered 4 with muslin (fabric). The jars with muslin developed no maggots but the open jars had maggots.
• This is important because cells come from other cells.
Prokaryote• Are unicellular - 1• Have no formed
nucleus• Are very
disorganized.• Have a cell wall,
cytoplasm, ribosomes, bacteria have cell membrane
• Bacteria are prokaryotes
Eukaryote• Have a Nucleus• Have cell membrane
bound organelles• Are very organized.• Can be singular or multi-
cellular.• Have these other organelles;
nuclei, mitochondrion, lysosome, golgi apparatus, ribosomes
What’s Inside?• Organelles
– tiny structures within a cell that perform specific jobs to keep the cell alive
Cytoplasm - gel-like material inside cells
Cytoplasm
Cytoplasm
• Contains materials involved in cell metabolism.
• Gives the cell its shape
Cell Membrane - protects cell and controls what enters and leaves the cell.
Cell Membrane
The Cell Membrane• Is semi-
permeable, or selectively permeable.
• Is made of a phospho-lipid bi-layer.
• Helps maintain the shape of the cell.
Nucleus - directs cell activities (brain)
Nucleus
The Nucleus and The Nucleolus
• Serves as the control center of the cell and contains Deoxyribonucleic Acid (DNA)
• Nucleolus- Contains RNA
• Nuclear membrane – Control what goes in or out of the Nucleus.
Endoplasmic Reticulum (ER) - movement of materials throughout cell
ER
Endoplasmic Reticulum
•Rough ER contains Ribosome's.
•Smooth ER has no Ribosome's
Ribosome - makes proteins
Ribosomes
Ribosome's
• Grain like Structures
• Sites of protein synthesis
Mitochondria - the powerhouse of the cell (converts food into energy for the cell)
Mitochondria
Mitochondria
• Makes ATP/ Energy• These organelles
are more plentiful in active cells
Chromatin/Chromosomes (DNA) - contains genetic information (inside the nucleus)
Chromatin is the combination of DNA and proteins that make up the contents of the nucleus of a cell
Chromosomes• Contains code
that guides all cell activities
• They are found in the nucleus.
• Chromosomes contain the genes that determine an organisms characteristics.
The Centrioles• Involved in cell
division• Produce
Microtubules that pull chromosomes apart.
• Microtubules also give the cell structure.
• Are found inside the nucleus.
Golgi Body - packages and moves proteins
Golgi Body
Golgi Bodies
• Look like stacks of pancakes.
Lysosome - digests wastes
Lysosome
Lysosomes
• Powerful chemicals that break things down.
Vacuole - storage of food and water
Vacuole
Vacuoles
• Plays a role in intercellular digestion
• Store food and water.
• Are much larger in plant cells.
Cells
Plant Cells
• Have two main differences from animal cells
• 1. Cell wall = a tough, usually flexible but sometimes fairly rigid layer that surrounds a cell
• 2. Chloroplasts = organelles found in plant and other eukaryotic organisms that conduct photosynthesis
Cell Wall - supports and protects PLANT cells (not found in animal cells)
Cell Wall
Chloroplast - takes energy from the sun and makes food for the PLANT cell (not found in Animal Cells)
Chloroplast
Cell Reproduction
• All organisms REPRODUCE. • Why?
– This allows for growth, development and the survival of the species
Gamete – The male or female reproductive cell that contains half of the DNA
Egg Cell – The Ovum; the female reproductive cell (gamete); usually not mobile
Sperm – The male reproductive cell (gamete) ; usually mobile
There are 2 types of reproduction
1. Asexual Reproduction
– Requires A single parent!!! (sorry, just ONE).
Asexual Reproduction (cont)…
• Results in the offspring having the same hereditary material (DNA)
• In other words, the new cells are an exact copy of its parent (allow for little variation among species)
Asexual Reproduction (cont)…
Types of Asexual Reproduction
• Fission – cell splits in half (ex: Amoeba)
Types of Asexual Reproduction (cont)…
• Budding – a new organism grows off from the side of an adult (ex: Hydra)
Types of Asexual Reproduction (cont)…
• Regeneration – a new organism grows from a severed body part (ex: starfish)
The structure of a chromosome
ChromosomeCentromere
Chromatid arm
Gene
How do we replace old cells?• Mitosis
– The process in which the newly duplicated chromosome pairs are separated from each other
MITOSIS
Mitosis
The process of cell division which results in the production of two daughter cells
from a single parent cell.
The daughter cells are identical to one another and to the original parent
cell.
Mitosis can be divided into stages
• Interphase
• Prophase
• Metaphase
• Anaphase
• Telophase
• Cytokinesis
InterphaseThe cell prepares for division
• Animal Cell – DNA replicated– Organelles replicated– Cell increases in size
• Plant Cell– DNA replicated– Organelles replicated– Cell increases in size
Interphase
Animal Cell Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
ProphaseThe cell prepares for nuclear division
• Animal Cell– Packages DNA into
chromosomes
• Plant cell– Packages DNA into
chromosomes
Prophase
Animal Cell Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
MetaphaseThe cell prepares chromosomes for
division• Animal Cell
– Chromosomes line up at the center of the cell
– Spindle fibers attach from daughter cells to chromosomes at the centromere
• Plant Cell– Chromosomes line up
at the center of the cell– Spindle fibers attach
from daughter cells to chromosomes at the centromere
Metaphase
Animal Cell Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
AnaphaseThe chromosomes divide
• Animal Cell– Spindle fibers pull
chromosomes apart– ½ of each
chromosome (called chromotid) moves to each daughter cell
• Plant Cell– Spindle fibers pull
chromosomes apart– ½ of each
chromosome (called chromotid) moves to each daughter cell
Anaphase
Animal Cell Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
TelophaseThe cytoplasm divides
• Animal Cell– DNA spreads out– 2 nuclei form– Cell wall pinches in to
form the 2 new daughter cells
• Plant Cell– DNA spreads out– 2 nuclei form– New cell wall forms
between to nuclei to form the 2 new daughter cells
Telophase
Animal Cell Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
What happens to a cell after Mitosis is complete?
• Cytokinesis– Cell splits into two identical daughter cells
with complete set of organelles
Mitosis Animation
http://www.cellsalive.com/mitosis.htm
Animal Mitosis -- ReviewInterphase
Prophase
Metaphase
Anaphase
Telophase
Interphase
Plant Mitosis -- ReviewInterphase
Prophase
Metaphase
Anaphase
Telophase
Interphase
How did you get here?• Sexual Reproduction
– Reproduction in which two (2) parents are involved
– Sex cells are called gametes (egg and sperm cells are gametes)
What is sexual reproduction?• Sexual reproduction
– starts with the formation of gametes and ends when one gamete joins another gamete. The joining of egg and sperm is called fertilization, resulting in the production of a zygote
zygote
How are gametes produced?• Meiosis
– A process whose purpose is to reduce the chromosome number in the cells
– Produces 4 new cells with half the number of chromosomes as the parent
Parent Cell1st Division
Meiosis – two divisions of the nucleus
2nd Division – 4 new daughter cells with ½ the # of chromosomes
Meiosis continued• Diploid Cells: have two of every
chromosome (body cells)
• Haploid Cells: have just one chromosome from each pair (gametes)
MEIOSIS
Meiosis
Meiosis is the type of cell division by which germ cells (eggs and sperm) are produced.
One parent cell produces four daughter cells.
Daughter cells have half the number of chromosomes found in the original
parent cell
Meiosis
During meiosis, DNA replicates once, but the nucleus divides twice.
Meiosis
Four stages can be described for each division of the nucleus.
Meiosis IFirst division of meiosis
First Division of Meiosis• Prophase 1: Each chromosome duplicates and
remains closely associated. These are called sister chromatids.
• Metaphase 1: Chromosomes align at the center of the cell.
• Anaphase 1: Chromosome pairs separate with sister chromatids remaining together.
• Telophase 1: Two daughter cells are formed with each daughter containing only one chromosome of the chromosome pair.
Prophase I
http://everyschool.org/u/logan/cellreproductionx/rogersa/research/meiosis.html
Prophase I
http://everyschool.org/u/logan/cellreproductionx/rogersa/research/meiosis.html
Metaphase I
http://everyschool.org/u/logan/cellreproductionx/rogersa/research/meiosis.html
Telophase I
http://everyschool.org/u/logan/cellreproductionx/rogersa/research/meiosis.html
Meiosis
Second Division of Meiosis
Second Division of Meiosis• Prophase 2: DNA does not replicate.
• Metaphase 2: Chromosomes line up at the center of the cell
• Anaphase 2: Centromeres divide and sister chromatids move separately to each pole.
• Telophase 2: Cell division is complete.
Four haploid daughter cells are formed.
Prophase II
http://everyschool.org/u/logan/cellreproductionx/rogersa/research/meiosis.html
Metaphase II
http://everyschool.org/u/logan/cellreproductionx/rogersa/research/meiosis.html
Telophase II
http://everyschool.org/u/logan/cellreproductionx/rogersa/research/meiosis.html
Meiosis
http://www.biosci.uga.edu/almanac/bio_103/notes/apr_3.html.
Meiosis Animation
http://www.rothamsted.bbsrc.ac.uk/notebook/courses/guide/movie/meiosis.htm
Differences in Mitosis & Meiosis
• Mitosis– Asexual– Cell divides once– Two daughter cells– Genetic information is
identical
• Meiosis– Sexual– Cell divides twice– Four haploid daughter
cells– Genetic information is
different
Comparison Animations
http://www.pbs.org/wgbh/nova/baby/divi_flash.html
http://www.usoe.k12.ut.us/curr/science/sciber00/7th/genetics/sciber/animatin.htm
Cells (basic unit of life)
Tissues(A group of cells performing a similar function)
Organs(A group of tissues performing a similar function)
Organ System(A group of organs performing a similar function)
Organism
An individual living thing made up of smaller parts that work together
(You and Me)