unit 1: wellness & homeostasis · what is unit 1 about? wellness & homeostasis • 0....
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UNIT 1: WELLNESS & HOMEOSTASIS
Biology notes 1Mr.Yeung
WHAT IS UNIT 1 ABOUT?Wellness & Homeostasis
• 0. Wellness (Reading labels/homeostasis/serving size)
• 1. Cell Biology (Ch.3)
• Cell organelles
• Cell types
• 2. Membrane structure and Function (Ch.4)
• 3. Metabolism and Energy (Ch.6)
• ATP
WHAT DO YOU KNOW ABOUT THE HUMAN BODY?• Take each of the organs, tissues, cells, parts of the body
and arrange them in their appropriate locations.
CONCEPT MAP OF THE UNIT
Understand Apply
Relate
Read
Cells
Energy
Cell origins
InstrumentsProkaryoticEukaryotic
Cell theory
Types of microscopesOrganelles
Membrane
Enzymes
Diffusion
Do this!
1. Grab a slide and place a drop of methylene blue on it.2. Take a toothpick and rub it against the insides of your
cheeks (don’t do it too hard!)3. Stir the end of the toothpick into the methylene blue4. Cover the drop with a cover slip5. Place under the microscope and observe
WHAT DID YOU JUST SEE?
Now… imagine that you are living the 16th century.
What can you tell people what you just saw?
http://www.bbc.co.uk/staticarchive/742e4ca780f38fc30d7f645838936c65b92c744f.jpg
More importantly, how do you prove and justify your points?
In the past:Spontaneous genera0on
•Since Aristotle’s time (4 B.C), there was an belief that cells magically appeared.
•Eg) Leave meat out and you’ll get maggots
•This was proved not true by (1765 - 1767), Lazzaro Spallanzani
What is a cell?
The smallest functional and structural living unit of life
What does that mean?If we were to break down an organism to the
smallest living part, you will see cells.
Red blood cellsNerve cells
Plant Cells
WHERE DO CELLS COME FROM?
Cell theory1.All living organisms are composed of one or more cells
2.Cells are the basic functional and structural unit of an organism.
3.All cells must come from pre-existing cells!
1. Use energy 3. Control functions2. Sense the environment
5. Eliminate wastes4. Build and repair
6. Reproduce
Life’s requirements for survival Keep the 6 requirements in mind to fully
understand and appreciate cell biology
CELL TYPES
Eukaryotic Cell Prokaryotic Cell
Can be both unicellular or multicellular Unicellular
Lacks a membrane-bound nucleusContains a nucleus (with red blood cells as an exception)
Bacteria are prokaryoticAnimal cells, plant cells, fungi and protists are eukaryotes
Eukaryotic Cell
Prokaryotic Cell
PROKARYOTIC CELLS• Pro - “before” Karyote - “nut
or kernal”, prokaryotic cells are thought to have existed before eukaryotic cells
• They lack a true membrane-bounded nucleus.
• Contains a cell wall containing peptidoglycan, an unique molecule for bacteria, made from sugar molecules joined together.
A plasma membrane still exists
PROKARYOTIC CELLS
• The peptidoglycan is a key component in designing antibiotics.
• A capsule further surrounds the cell wall containing a slime layer.
Prokaryotic cells’ locomotion
• Contains a long tail called flagella to help bacteria move.
• Some contains a fimbriae that are tiny “arms” that stick out to attach to surfaces.
PROKARYOTE’S GENETIC MATERIAL
• Contains a single chromosome in the nucleiod (not surrounded by membranes).
• Contains plasmids which are small rings of DNA.
• Smaller ribosomes for protein synthesis.
PROKARYOTE CELL SUMMARYStructure & Locomotion
• cell wall with peptidoglycan and capsule
• flagella for locomotion
• fimbriae for attachement
Genetic storage
• 1 chromosome (circular DNA)
• located in nucleoid in cytoplasm
• contains plasmids but not restricted to prokaryotes
EUKARYOTIC CELL
ORGANELLES
• Review of organelles:
• Nucleus (Nuclear membrane, nucleolus,)
• Cytoplasm
• Mitochondria
• Vacuoles
• Ribosomes
• Endoplasmic reticulum (Rough & Smooth)
• Golgi apparatus
• Lysosome
• Cilia
• Cell membrane
CELL MEMBRANE (CH.4)Key Points:
•Determines what can come in and leave the cell.
•Contains a phospholipid bilayer
•Two layers with a “head” near the surface and “tail” inside the bilayer.
•The “head” portion is hydrophilic (water loving) while “tail” is hydrophobic (water fearing)
•Proteins are scattered around the membrane
More info on the cell membrane in the next chapter
NUCLEUS
Key points:
· Function: control center of cell
· Contains DNA
· Surrounded by double membrane (nuclear envelope)
· Continuous with the rough ER
· Nuclear pores: control what enters/leaves nucleus
· Chromatin: complex of DNA + proteins; makes up
chromosomes
· Nucleolus: region where ribosomal subunits are formed
RIBOSOMESKey Points: Func0on: protein synthesis Composed of rRNA + protein Large subunit + small subunit
Types: Free ribosomes: float in cytosol,
produce proteins used within cell
Bound ribosomes: aFached to ER, make proteins for export from cell
The next 3 organelles are classified as the Endomembrane system- collectively functions as a regulatory system for proteins and
metabolism
ENDOPLASMIC RETICULUM (ER)What it is: Network of membranes and sacs
Types: Rough ER: ribosomes on surface
Func0on: package proteins for secre0on, send transport vesicles to Golgi, make replacement membrane
Smooth ER: no ribosomes on surface Func0on: synthesize lipids, detox drugs & poisons, store Ca2+
GOLGI APPARATUSFunc<on: synthesis & packaging of materials (small molecules) for transport (in vesicles); produce lysosomes
Series of flaFened membrane sacs (cisternae)
LYSOSOMEFunc<on: intracellular diges0on; recycle cell’s materials; programmed cell death (apoptosis)
Contains hydroly<c enzymes
VACUOLESFunc<on: storage of materials (food, water, minerals, pigments, poisons)
Membrane-‐bound vesicles Eg. food vacuoles, contrac0le vacuoles
Plants: large central vacuole -‐-‐ stores water, ions
MITOCHONDRIAFunc0on: site of cellular respira.on Double membrane: outer and inner membrane
Cristae: folds of inner membrane; contains enzymes for ATP produc0on; increased surface area to ATP made
Matrix: fluid-‐filled inner compartment
CILIA AND FLAGELLA
Flagella: long and few; propel through water Cilia: short and numerous; locomo0on or move fluids
Endosymbiont theory
The Theory on how the first
Eukaryotic cell started
·Mitochondria & chloroplasts
share similar origin
·Prokaryotic cells engulfed by
ancestors of eukaryotic cells
·Evidence:
·Double-membrane structure
(mitochondria)
·Have own ribosomes & DNA
·Reproduce independently
within cell