Life Science: Chapter 2

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Life Science Chapter 2

• Features of Life and the Cell

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Review

• Do you remember what it means to be alive?
  (biological speaking)

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Features of Living Things

• Reproduce
• Grow and Develop
• Need Food
• Utilize Energy
• Made of Cells
• Response
• Adapt to environment

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Reproduce

• Reproduce to form offspring similar to the
  parents.

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Grow and Develop

• Living things grow by using energy from the
  environment
• Development all the changes that occur as a
  living thing grows.

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Need Food

• Living things need food to obtain energy for life
  processes
• Living things that consume other living things
  are called consumers.
• We are consumers
• Living things that produce their own energy are
  producers.
• Ex Plants

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Use Energy

• Living things breakdown food to obtain and
  utilize the energy.
• This process is called cellular respiration.

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Living Things are Made of Cells

• A cell is the basic building block of life.
• Some organisms are made of one cell, and some are
  made of multiple cells.
• cells

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Response

• Living things respond to changes in the
  environment.

Ex pupil
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Adapt to Environment

• Living things are adapted to their environment

An adaptation is a trait makes a living thing
better able to survive
Ex a polar bears thick coat
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SO

• Are Flames Alive?

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Chemistry of Life

• Only 7 elements make up 99 of the matter in
  living things
• Oxygen (O)- 65
• Carbon (C)- 18.5
• Hydrogen (H)- 9.5
• Nitrogen (N)- 3.3
• Calcium (C)- 1.5
• Phosphorus (P)- 1.0
• Sulfur (S)- 0.3

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Cell Theory

• In 1664, Robert Hooke was the first scientist to
  use the word cell.
• Late 19th century. Schleiden and Schwann
  performed experiments to determine which living
  things have cells.
• Formed a theory

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Cell Theory

• What is a theory?
• Something that has been test over a long period
  of time, by many different people and widely
  accepted as truth
• Explanation of a natural phenomenon

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Cell Theory

• Major Ideas
• All living things are made of one or more cells
• Cells are the basic units of structure and
  function in living things
• All cells come from other cells

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Check your understanding

• Questions 1-5 (homework?)

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Section 2.2

• Cell Parts and Their Jobs

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There are many different parts to a cell. These
parts work together to perform complex processes
for the cell.
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Cell Membrane

• Cell Membrane gives the cell shape and controls
  what goes in and out of cell

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Nucleus

• Nucleus brain. controls most of the cells
  activities.
• Protein manufacturing
• Heredity
• Stores Chromosomes
• Contains information which determines traits of
  the organism
• Nucleolus dark spot in nucleus. Helps to
  make ribosomes.
• Nuclear Membrane surrounds nucleus. Control
  what moves in and out of nucleus.

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Nucleus
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Cytoplasm

• Cytoplasm is a clear jellylike substance.
• Makes up most of the cell
• Where the organelles are and where some chemical
  reactions take place.
• Contains a network of canals for movement of
  particles throughout the cytoplasm (E.R.)

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Cytoplasm

• Contains organelle responsible for packaging and
  storing chemicals that leave cell.
• Sacs filled with digestive chemicals.
• Destroy dead cell parts
• Destroy bacteria
• Breakdown large molecules

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Ribosome

• Found in cytoplasm and along network of canals.
• Responsible for making proteins

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Mitochondria

• Found in cytoplasm
• Powerhouse
• Form energy from digested food.
• Where do you think you would find cells that
  would have a large number?

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Vacuole

• Found in cytoplasm
• Storage
• Water, food, minerals
• Plant cells have large central vacuole
• Animal cells also contain vacuoles

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Centrioles

• located in cytoplasm
• Aid with cell reproduction
• mitosis

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Chloroplasts

• Found only in plant cells
• Cytoplasm
• Contain the pigment chlorophyll
• Gives plants green color
• Aids with photosynthesis by trapping light from
  the sun for energy.

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Cell Wall

• Structure only found in plant cells
• Outside of cell membrane
• Give rigidity and support to cell and then to
  plant

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cells

• Everything is made of cells.
• Yet another example how we are the same but
  entirely different
• How big is a cell?

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Check your Understanding..

• Questions 6-9

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Section 23

• Special Cell Processes

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• We are going to answer the question
• How does a cell get nutrients it needs for its
  life processes?
• A cell uses many different ways to move molecules
  across its membrane
• The membrane is selectively permeable
• We will only discuss Diffusion and Osmosis
• Remember Everything in a cells environment must
  remain in equilibrium (homeostasis).

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Diffusion

• The movement of molecules from an area where
  there is a large amount to where there is a small
  amount.
• Fig. 2-11 pg. 39

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Osmosis

• Movement of water molecules across a membrane
• Movement from where there is a large amount to
  where there is a small amount.
• Fig. 2-12 pg 40
• red blood cells and distilled water

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Organization

• Starts with a cell
• A group of similar cells that carryout a similar
  function is a tissue
• A group of tissues that work together is an organ
• A group of organs that work together to do a
  certain job is an organ system
• All organ system put together is an organism

• CELL
• TISSUE
• ORGAN
• ORGAN SYSTEM
• ORGANISM

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Check Your Understanding

• In osmosis, which substance diffuses?
• How does diffusion make it possible for you to
  smell different odors?