Chapter One

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Chapter One

• What is Life?

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• Organisms are living things. All living things
  share six important features
• Cellular organization
• Contain similar chemicals
• Use energy
• Grow and develop
• Respond to their surroundings
• reproduce

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• A cell is the basic unit of structure and
  function in an organism.
• Unicellular, or singled-celled, organisms include
  bacteria, the most numerous organisms on Earth.
• Multi-cellular organisms are composed of many
  cells.

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• Cells are composed of chemicals.
• Water is the most abundant chemical in cells.
• Carbohydrates provide energy to the cell.
• Proteins and lipids are the building materials of
  the cells.
• Nucleic acids are the genetic materials that
  direct the cells activities.

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• Living things grow and develop.
• Growth is the process of becoming larger.
• Development is the process of change that occurs
  during an organisms life to produce a more
  complex organism.

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• Stimulus and Response
• A change in an organisms surroundings that
  causes the organism to react is called a
  stimulus.
• An organism reacts to a stimulus with a response
  an action or change in behavior.
• For example, the stove is on, and by accident,
  you touch the stove (hot-stimulus).
  Immediately you pull away from the stove
  (reaction).

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• Another characteristic of organisms is the
  ability to reproduce, or produce offspring that
  are similar to the parents.
• People once believed that living things arise
  from non-living things FALSE! However this
  concept is called spontaneous generation.
• We know that all organisms need four things to
  stay alive
• Energy
• Water
• Living space (room to grow and develop)
• Stable internal conditions (ex body
  temperature)
• The maintenance of stable internal conditions
  despite changes in surroundings this is called
  Homeostasis.

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• Autotrophs are organisms that make their own
  food.
• Heterotrophs are organisms that cannot make their
  own food.
• All organisms need food, shelter, and water.
• F. Redi
• Francesco Redi - One of the first to disprove
  spontaneous generation. An Italian doctor who
  proved maggots came from flies. (Italian 1668)
• Spontaneous Generation The idea that organisms
  originate directly from nonliving matter. "life
  from nonlife"

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F. Redi

• Redi's Problem
• Where do maggots come from? Hypothesis Maggots
  come from flies.
• Redi put meat into three separate jars.
• Jar 1 was left open.
• Jar 2 was covered with netting.
• Jar 3 was sealed from the outside.

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F. Redi

• Jar-3 - Sealed No maggots developed.
• Jar-2 - Covered with netting, Maggots appeared on
  the netting. Flies were observed laying eggs on
  the netting.
• Jar-1 - Left open Maggots developed. Flies were
  observed laying eggs on the meat in the open jar.

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Louis Pasteur
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Louis Pasteur

• Pasteur boiled some broth to kill any microbes
  present. With special glassware, he allowed air
  to circulate over the broth, but prevented
  microbes in the air from reaching the broth. As
  Pasteur expected, no microbes appeared in the
  broth. Pasteurs findings showed that microbes
  were not spontaneously generated from the broth
  itself. Microbes would only appear in the broth
  if they were allowed in with the air. He clearly
  showed that even for microbes, life came only
  from lifeMicroscopic beings must come into the
  world from parents similar to themselves.

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Redi and Pasteur

• Read pg 22 and pg 23 and answer the following
  questions
• In Redis experiment, what factors were identical
  in each test?
• How did the tests differ in Redis experiment?
• What factor is the variable in Redis experiment?
• What is the variable in Pasteurs experiment?

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Redi and Pasteur

• In Redis experiment, what factors were identical
  in each test? Both had meat in a jar and both
  were exposed to air.
• How did the tests differ in Redis experiment?
  Redi covered one jar with a cloth.
• What factor is the variable in Redis experiment?
  The cloth covering the jar flies could not
  reach the meat.
• What is the variable in Pasteurs experiment?
  Whether or not the broth was boiled.

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• Discovering Cells

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The Cell Theory

• The Cell Theory
• All living things are composed of cells.
• Cells are the basic unit of structure and
  function in living things.
• All cells are produced from other cells.

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• Looking Inside Cells

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Diagram of 3 types of Cells

• Bacteria Cell Nerve Cell
• Blood Cell

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Diagram of an Animal Cell
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• Inside a cell are tiny structures called
  organelles, which carry out the specific
  functions in the cell.

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Cell Membrane

• Let's look at the cell membrane and see how the
  membrane keeps all of the pieces inside. When you
  think about a membrane, imagine it is like a big
  plastic bag with some tiny holes. That bag holds
  all of the cell pieces and fluids inside the cell
  and keeps any nasty things outside the cell. The
  holes are there to let some things move in and
  out of the cell.

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The Nucleus

• The cell nucleus is like the brains of the cell.
  It helps control eating, movement and
  reproduction. If it happens in a cell, chances
  are the nucleus knows about it. The nucleus is
  not always in the center of the cell. You
  probably won't find it near the edge of a cell
  because that might be a dangerous place for the
  nucleus to be. It will be a big dark spot
  somewhere in the middle of all of the cytoplasm.
  If you don't remember, the cytoplasm is the fluid
  that fills cells.

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The Nucleus

• Floating in the nucleus are thin strands called
  chromatic, which contain the genetic material, or
  the instructions for cell functions.

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Cytoplasm

• Cytoplasm is the region between the cell membrane
  and the nucleus. Many organelles are found in
  the cytoplasm. Cytoplasm is a clear-whitish
  liquid.

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Mitochondria

• The mitochondria are known as the powerhouses of
  the cell. They are the organelles that act like a
  stomach that takes in nutrients, breaks them
  down, and creates energy for the cell.

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Endoplasmic Reticulum

• Endoplasmic Reticulum carries proteins and other
  materials from on part of the cell to another.

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Ribosomes

• Ribosomes are the protein builders or the protein
  synthesizers of the cell. They are like
  construction guys who take one amino acid at a
  time and build long protein chains.

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Golgi

• Collections of sacs and tubes called Golgi bodies
  distribute proteins and other materials
  throughout the cell.

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Lysosomes

• You will find organelles called lysosomes in
  nearly every animal-like eukaryotic cell.
  Lysosomes hold enzymes that were created by the
  cell. They exist in the cell to digest. They
  might be used to digest food or break down the
  cell when it dies.

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The Plant Cell
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The Cell Wall

• While cell membranes might be around every cell,
  cell walls made of cellulose are only found in
  plant cells. Cell walls are made up of
  specialized sugars called cellulose. This
  cellulose provides a protected framework for a
  plant cell to survive and gives the plant its
  shape.

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Vacuoles

• Vacuoles might store food or any variety of
  nutrients the cell would need to survive. They
  might even store waste products so that the rest
  of the cell is protected from contamination.
  Eventually those waste products would be sent out
  of the cell.

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Chloroplasts

• Chloroplasts are the food producers of the cell.
  They are only found in plant cells. Every green
  plant you see is working to convert the energy of
  the sun into sugars. That process happens in the
  chloroplast

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Bacteria Cell

• What important organelle is a bacteria lacking?

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Bacteria Cell

• A bacterial cell is smaller than a plant or
  animal cell and does not contain a nucleus.
• Organisms whose cells lack a nucleus are called
  prokaryotes.
• Organisms whose cells contain a nucleus are
  called eukaryotes.