Download Cells - Tuckahoe Common School District

Cells
The Building
Blocks of Life
How Did the Earth Form?
• We do not know for
certain how the Earth
formed.
• Most scientists agree
that the Earth formed
about 4.6 billion years
ago.
• That is 4,600,000,000
years ago.
Two Theories of How Life on
Earth Formed
• Stanley Miller’s
Theory of Life
• The Volcanic Theory
of Life
Stanley Miller’s Theory of Life
• This theory states that
a mixture of gases
and water was struck
by lightning and
formed a “tar-like”
substance that
allowed living things
to develop.
• Also known as
“Primordial Soup”
The Volcanic Theory of Life
• The Volcanic Theory of Life states that the
cooling planet had lots of volcanoes putting
gases into the air.
• These gases condensed into rain that formed
oceans.
• Single cell organisms evolved into plant life then
animal life.
How did Cells Form?
• Several Theories of How Cells Formed:
– Cells arose in shallow pools containing “soup”
of chemicals. These chemicals become
combined and formed cells.
– Cells formed in beds of clay that allowed
substances (chemicals) to be contained and
produce living things – cells.
– Meteors and asteroids carried water,
containing life (cells) to the Earth.
Which Cell Theory Is True?
• We still do not know for sure how cells
formed.
Spontaneous Generation?
• The Theory of Spontaneous Generation
states that life could arise from non-living
matter.
– This theory was disproved in 1668 by
Francesco Redi who used raw meat for his
experiments.
Francesco Redi
Redi’s Experiment
Producers and Consumers
• A producer is any
organism that makes
it’s own food.
– Example: green plants
• A consumer is any
organism that can not
produce it’s own food.
– Consumers are
dependent on other
organisms to survive.
– Example: Man
How Do Producers Make Food?
• Photosynthesis: the process by which
green plants convert sunlight into food.
– As a waste product, oxygen is released.
– At some point in history, early cells evolved
and became able to perform photosynthesis.
• This is important because this allowed an
oxygen atmosphere to form and eventually
allows for animal life to evolve.
Characteristics of Living Things
• All living things share characteristics,
they:
– Are made of cells
– Are able to move
– Perform complex chemical activities
– Are able to grow and develop
– Are able to respond to their environment
– Are able to reproduce
What is a Cell?
• The cell is the basic building block of
all living things.
– The first cells on Earth are thought to have
evolved ~3.5 billion years ago.
– These cells could not produce their own
food.
All living things are made of cells
Plant Cells
Animal Cells
All living things are able to move
All living things perform
complex chemical activities
“building up and breaking
down”
• Metabolism is the sum total of all the
chemical reactions that occur in a living
thing.
– In humans these chemical reactions are
ingestion, digestion, respiration, and
excretion.
Nutrition
• Nutrition is the process of obtaining food
and breaking it down into a useable form
for cell absorption.
Ingestion
• Ingestion is taking in food to process.
Digestion
• Digestion is
the process of
breaking
down food
into simpler
substances.
Transport
• Nutrients and other
necessary
materials are
delivered to all the
cells of the
organism; wastes
are carried away.
Respiration
• Respiration is the process of taking in
oxygen and using it to produce energy.
Excretion
• Excretion is the process of getting rid
of waste material.
Regulation
• Regulation is the
control and
coordination of all
life functions. It
also involves the
response of an
organism to
changes in the
environment.
All living things are able to grow
and develop
• Life span is the
maximum
length of time
that an
organism is
expected to
live.
All living things are able to
respond to their environment
• A stimulus is
something that comes
from outside the
organism or from
within the organism
that triggers a
reaction.
Examples:
cold breeze
stomach growl
• A response is the
reaction that occurs
as a result of the
stimulus.
Examples:
goose bumps
eat food
All living things are able to
reproduce
“Like produces like”
• Sexual reproduction:
– Requires two parents
– Results in offspring that
show variations
• Asexual reproduction:
– Requires one parent
– Results in identical
offspring with no
variations
Both forms of reproduction give a chemical
“blueprint” to the next generation.
Cellular Reproduction
Egg and Sperm Cells Fertilization
Meiosis - Sexual Reproduction
Result is daughter cells with half the chromosomes
Mitosis – Asexual Reproduction
Result is two identical cells
What are the Needs of Living
Things?
• In order to survive all living things need:
– Energy
– Food
– Water
– Oxygen
– Living space
– To maintain a proper temperature
How Do Living Things Maintain
Proper Temperature
• Homeostasis is the ability of an organism to
keep the conditions inside the body the same
even though external environmental
conditions change.
• Warm blooded animals maintain a constant
body temperature at all times.
– Examples are man and mammals
• Cold blooded animals have body
temperatures that change with the
environment.
– Examples are fish and reptiles
What Makes Up All Living Things?
“The Chemistry Of Life”
• All living things are made of elements and
compounds.
What is an Element?
• An element is a pure substance that can
not be broken down into any simpler
substances.
– Only 90 natural elements exist on earth.
– Only 11 elements are common in living things.
– 4 elements (carbon, nitrogen, oxygen and
hydrogen) make up 96% of the weight of the
human body.
What is a Compound?
• A compound is formed when 2 or more
elements join together chemically.
– Examples are: water H2O, and sugar C6H12O6
A water molecule is
an example of a
compound
Cell Theory
• The current cell theory
states that:
– All living things are
made of cells.
– Cells are the basic unit
of structure and
function in living things.
– Living cells only come
from other living cells.
What Are Cells Made Of?
• Organelles, or “tiny organs”, are
the structures that make up a cell.
• Organelles were discovered by
Robert Hooke in 1665 while looking
at cork cells.
How Do Cells Function?
• Each of the organelles in a cell has a defined
function.
• There are many organelles that make up a cell.
– These include the cell wall, cell membrane,
nucleus, cytoplasm, endoplasmic reticulum,
ribosomes, lysosomes, mitochondria, vacuoles,
chloroplasts.
• All organelles working together create the cells
structure.
Plant Cells vs Animal Cells
Plant Cell
Animal Cell
Cell Organelles – Cell Wall
• The cell wall provides support and
protection for the cell.
• The cell wall is rigid.
• Cell walls are only found in plant cells.
Cell Wall – only in plants
Cell Organelles – Cell Membrane
• The cell membrane is the “doorway” of the cell.
• Cell membranes control the movement of
materials into and out of the cell.
– Pores are the openings in the cell membrane.
• Cell membranes provide support and protection.
– In plant cells the cell membrane is found just
inside the cell wall.
– In animal cells the cell membrane is the outermost
organelle.
Cell Membrane
Cell Organelles - Nucleus
• The nucleus is the “control center”, or
“brain” of the cell which controls all
activities in the cell.
• The nucleus has three parts:
– Nuclear membrane
– Chromosomes
– Nucleolus
Cell Organelles - Nucleus
• The nuclear membrane controls the
movement of materials into and out of
the nucleus.
• The chromosomes direct the activities
within the cell and also pass on genetic
traits to the next generation.
• The nucleolus, or “little nucleus” is the
site of ribosome production.
Cell Organelles Cytoplasm
• Cytoplasm
is the clear,
thick jellylike
substance
that
contains all
the
organelles.
Cell Organelles – Endoplasmic
Reticulum
• The
endoplasmic
reticulum, or
ER, is the
tubular
transportation
system
throughout the
cell.
Endoplasmic Reticulum
Smooth and Rough
Cell Organelles - Ribosomes
• Ribosomes are the protein factories of
the cell.
• Most ribosomes are found attached to the
outside of the endoplasmic reticulum.
– This location helps the cell with efficiency of
production and transport.
Ribosomes
Cell Organelles - Lysosomes
• Lysosomes are the “clean up crew” of
the cell.
• Lysosomes are involved in the digestive
process of the cell.
– Enzymes break down large food into smaller
bits for the mitochondria to use.
– Lysosomes are not common in plant cells.
Cell Organelles - Mitochondria
• Mitochondria are the “powerhouse” of
the cell and supply most of the energy for
the cell.
Cell Organelles - Vacuoles
• Vacuoles are the “storage tanks”
of the cell.
• Vacuoles can store food, water, or
waste.
– In plant cells vacuoles are common.
• Usually one large vacuole per cell.
– In animal cells vacuoles are not
common.
• Usually several small vacuoles per cell.
Cell Organelles - Chloroplasts
• Chloroplasts are the “energy producers”
of plant cells.
• Chloroplasts are only found in plant cells.
• Chloroplasts contain green chlorophyll that
captures energy from the sun.
How Do Materials Move Into and
Out Of The Cell?
• Materials enter and leave a cell by one of
three methods:
– Diffusion
– Osmosis
– Active Transport
What is Diffusion?
• Diffusion is the process by which
molecules of a substance move from
areas of high concentration to areas of low
concentration.
– The cell membrane is selectively permeable.
Diffusion from high concentration to low concentration
What is Osmosis?
• Osmosis is the diffusion of water into or
out of a cell.
• Both diffusion and osmosis do not require
the cell to use up it’s energy.
What is Active Transport?
• Active transport is the process by which
the cell “carries” a substance in or out.
• This requires the cell to use its energy.
• When does active transport occur?
– If the cell membrane is not permeable for the
substance.
– If the concentration levels inside and
outside the cell are not different enough.
What Is Cell Specialization?
• In multicellular organisms, cells not
only complete its own life activities, but
also performs a function that
contributes to the life of the organism.
• Within multicellular organisms there is
division of labor or specialization.
– The work of keeping the organism alive is
divided up among different parts of the
organism.
Levels of Specialization
Cells combine to form
Tissues combine to form
Organs combine to form
Organ systems combine to form
Organism
More Specialization
Students combine to form
Classes combine to form
Grades combine to form
Schools combine to form
District
Taxonomy
• Taxonomy is the science of naming,
describing and classifying organisms.
– Living organisms are organized into
categories based on characteristics.
– The classification system of living organisms
is arranged from a large category of kingdom
to smaller specific category of species
5 Kingdoms
• Monera: one-celled, no nucleus
• Protist: one-celled with nucleus
• Fungus: many-celled, heterotrophic, lacks
chlorophyll
• Plant: many-celled, autotrophic, contains
chlorophyll
• Animal: many-celled, heterotrophic
What is a Virus?
• A virus is different
form other living
organisms
because it lacks
cellular
organization.
Herpes simplex virus