Download The Twelve Days of Middle School Science

The Twelve Days of Middle
School Science
Day 1: Cell Theory
(& structure, organelles & functions,
processes)
Cell Theory
• 1. All organisms (living things) are made of one or
more cells. (Unicellular or multicellular)
• 2. The cell is the basic unit of all LIVING things.
– Hierarchy of all matter:
(?)Quarks & Leptons  Protons/ Neutrons/Electrons Atoms
Elements Molecules Compounds Proteins, Sugars, Acids, Lipids,
Minerals  Cells (LIFE) Tissues Organs Organ Systems Organisms
 Populations  Communities  Ecosystems  Biome Biosphere 
Earth  Solar System  Galaxy  Local Group  Galaxy Clusters 
Universe  Multiverse?
• 3. All cells come from existing cells.
(Mitosis=production of body cells or
Meiosis=production of sex cells)
Two Classifications* of Cells
O Prokaryotic Cells
1st form of life
O Have NO nucleus – DNA is free
(called the “nucleloid”)
O ONLY form Unicellular
organisms (one-celled)
O Example: Bacteria (e. coli,
staph, salmonella)
O
O Eukaryotic Cells
Evolved from prokaryotes
O Have a nucleus with bundled
DNA
O Can form unicellular or multicellular organisms.
O Example: Amoebas, plants
animals, fungi, protists
O
*Note: There many TYPES of cells (skin, muscle, hair, sex, etc.,); these are the two categories
that ALL cells fall under! It is the DNA within cells that controls what type of cell they will be.
Cell Organelles
EVALUATE:
• What shape are the mitochondria?
• How is the cell similar to a body system?
• Is the animal cell an open or closed system? Why?
Organelle & Function
*Cell Membrane: Outer cell lining for
protection
*Cytoplasm: Jelly-like liquid that
organelles float in
*Nucleus: “Control center” that contains
organism’s DNA
Nuclear Membrane: encloses and protects
nucleus; DNA can travel through to get to
the ER
Nucleolus: Produces ribosomes
*DNA: The hereditary material of
organisms
Chromosome: Thread-like structure of
DNA that holds genes
*Vacuoles: Store nutrients and waste
*Mitochondria: Jelly-bean shaped
producers of energy (ATP) for cell
*Ribosomes: Where proteins are made
*Endoplasmic Reticulum: Cell
transportation system (rough=has
ribosomes on top, smooth=no ribosomes)
*Golgi Apparatus/Body/Complex:
“Packaging center” which stores, modifies
and secretes proteins and lipids
Microtubules: protein filaments involved in
cell movement, shape, and cell division
(mitosis/meiosis).
Centrioles: contain microtubules and
involved in cell division (animals only)
Lysosomes: responsible for intracellular
digestion, “kamikazes”
* = KNOW THESE
Plant
Organelles
PLANT-SPECIFIC organelles:
*Cell Wall: Gives plant cells
shape and structure (rigidity),
made of cellulose
*Chloroplast: Site where
photosynthesis in plant cells
occurs
EVALUATE:
• What are some similarities
between plant and animal
cells?
• What do you notice about
the vacuole of the plant
cell?
• Why do you think plants
evolved to have cell walls
and animals did not?
Cellular Processes
• Respiration – the release of energy from sugar. Can
be aerobic (with oxygen) or anaerobic (w/o
oxygen—this is called fermentation)
• **Photosynthesis** - process by which plants
change light energy (sunlight) into chemical energy
(sugar)
• Mitosis – when cells split to create new body cells
• Meiosis – when cells split to reproduce sex cells
(ex: egg & sperm)
Cellular Processes, Cont.
• Diffusion - Movement of molecules from an
area of great concentration to an area of
lesser concentration.
• Osmosis – diffusion of water through cells
Summary of the Cell
Assessment & Homework
• Go to Ms. Cedillo’s website (8th Grade Science
The Twelve Days of Middle School Science)
• Look under Day 1 for these notes and other
resources
• HOMEWORK:
– STUDY cell structure & organelle functions – we will
have an assessment over this tomorrow