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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 multicellular.
• 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 semipermeable, or
selectively
permeable.
• Is made of a
phospho-lipid bilayer.
• 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)
Asexual Reproduction (cont)…
• In other words, the new cells are an exact
copy of its parent (allow for little variation
among species)
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
Chromatid arm
Centromere
Chromosome
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
Interphase
The 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
Prophase
The 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
Metaphase
The 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
Anaphase
The 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
Telophase
The 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 -- Review
Interphase
Prophase
Metaphase
Anaphase
Telophase
Interphase
Plant Mitosis -- Review
Interphase
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
Meiosis – two divisions of the nucleus
Parent Cell
1st Division
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 I
First 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/gen
etics/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)