Chapter 7
Cell Structure & Function
7.1 Life is Cellular
• Discovery of the Cell– Use of microscopes to discover cells –
1600s– Hooke
• looked at cork (plant material used in wine bottle stoppers)
• saw small chambers – “cells”
– Anton van Leeuwenhoek (Lee-when-hook)• Looked at pond water• saw small organisms
7.1 Life is Cellular
– Cell Theory• All living things are made of cells• Cells are the basic units of life• New cells are made from existing cells
7.1 Life is Cellular
• Basic Cell Info– Many shapes & sizes– Size:
• Typical 5-50 μm• Small 0.2 μm• Large 1,000 μm
– Cell membrane– DNA– 2 types:
• Prokaryotes & Eukaryotes (pro-carry-oats) (you-carry-oats)
7.1 Life is Cellular
• Prokaryotes– Do not have a
nucleus– DNA circular– Simple structures– Unicellular– Probably original
form of life– Bacteria
• Eukaryotes – Has a nucleus that
contains DNA– DNA linear– Has more
complicated/sophisticated structures
– Uni- or multicellular– Probably evolved from
prokaryotes– Plants, animals, fungi,
protists
7.1 Life is Cellular
7.2 Eukaryotic Cell Structure
• Cells are like factories– 2 major parts
• Nucleus• Cytoplasm
– Organelles – “little organs”
7.2 Eukaryotic Cell Structure
• Nucleus – control center/main office– Double layer nuclear envelope – Nuclear pores– Where DNA is located
• Uncoiled – chromatin• Coiled – chromosome
– Nucleolis (most)• Make ribosomes
7.2 Eukaryotic Cell Structure
• Ribosomes – assembly line– Small particles of RNA & protein – Follow instructions from DNA on how to
make/assemble proteins
7.2 Eukaryotic Cell Structure
• Endoplasmic Reticulum – packaging – Lipids of membranes are made– Proteins & other materials are exported
from the cell
• Smooth ER– Ribosomes not attached– Enzymes that detoxify & make lipids
• Rough ER– Export proteins– Ribosomes are attached
7.2 Eukaryotic Cell Structure
• Golgi Apparatus – customization shop– Modify, sort &
package proteins or other material to be stored or exported
7.2 Eukaryotic Cell Structure• Lysosomes - custodian
– Filled w/ enzymes– Breakdown macromolecules into useful
pieces– Recycle materials from old organelles – Clean up wastes
7.2 Eukaryotic Cell Structure
• Vacuoles - storage– Sacs – All plant cells store water
• Used for strength of support structures
– Some unicellular/animal cells • Contractile vacuole – controls amt. water in
the cell typically in cells surrounded by water
7.2 Eukaryotic Cell Structure
• Mitochondria/Chloroplasts - electricity•Mitochondria
•In plants & animals•Convert chem eng into ATP•2 membranes
•Inner folded up•All come from Mom!
7.2 Eukaryotic Cell Structure• Mitochondria/Chloroplasts - electricity
•Chloroplasts – like solar panels•In plants & other photosynthetic orgs•Convert light eng into ATP•2 membranes
•Contain chlorophyll
7.2 Eukaryotic Cell Structure
• Mitochondria/Chloroplasts – electricity– Theory
• Have own DNA• Thought that they were “eaten” by another cell
and became an organelle inside
7.2 Eukaryotic Cell Structure
• Cytoskeleton – building & transportation– Protein filaments (fibers) give cell its shape– Microfilaments
• Made of protein threads called actin• Help cells crawl
– Microtubules • Hollow• Used in cell division• Help cells swim
– Cilia (ex in trachea)– Flagella (ex sperm)
Structure & Function ReviewPicture Structure Function
Nucleus Store genetic information
Nucleolus Make ribosomes
Ribosomes Make proteins
Endoplasmic Reticulum
Make lipids
Structure & Function Review
Picture Structure Function
Golgi Apparatus
Ready materials to leave cell
Lysosomes Clean up wastes and bad organelles
Vacuoles Store material (usually H2O)
Mitochondria & Chloroplasts
Convert energy to ATP
Cytoskeleton Structure/support
7.3 Cell Boundaries
• Cell Membrane– Lipid bilayer
• Hydrophobic & hydrophilic ends
– Flexible – Regulation
• Selectively permeable
– Support– Protection
7.3 Cell Boundaries
• Cell membrane– Proteins & carbs.
• Transport – pumps & channels• Identification
– “Fluid mosaic”
7.3 Cell Boundaries
• Cell Wall– Plants & other orgs in watery env. or
that require rigidity – Made of carbs & proteins
• Cellulose• E. coli
– Porous
7.3 Cell Boundaries
• Diffusion through membranes– Cytoplasm
• Mostly H2O with solutes
– Concentration: solute/solvent or mass/volume
– Diffusion (pg 182)• Transport of material from one side of a
membrane to another• Equilibrium
– Osmosis• Diffusion of H2O
7.3 Cell Boundaries• Osmosis
– Isotonic– Hypertonic– Hypotonic
7.3 Cell Boundaries
• Osmotic pressure– Balance intake of & water loss– How do conc of solutes change osmosis?
– Fun fact: Pure H2O will kill you! Why?
– Vacuoles!
7.3 Cell Boundaries
• Passive vs active transport• Active transport
– Moving molecules against the concentration gradient
– Na+, K+, Ca+ commonly transported through pumps
7.3 Cell Boundaries
Movies!
• Cell membrane• Fluid mosaic• Passive transport • Active transport • Endocytosis
– Phagocytosis (cell eating)– Pinocytosis (cell drinking)– Exocytosis (cell excreting)
• Hypertonic solution w/ onion cells
Biology Chapter 7 Review
7.1 Life is Cellular – pg 169-173• Discovery of the Cell
– Hooke• Cork• Hollow, empty chambers• “cells” – tiny rooms like in a dorm• Note lab
– Van Leewenhoek• Pond water• Small organisms
– Cell Theory• All living things are composed of cells• All cells are the basic unit of living things• New cells are produced from existing cells
Biology Chapter 7 Review
7.1 Life is Cellular – pg 169-173• Discovery of the Cell
– Prokaryotes • Simple & small• No nucleus or organelles (except ribosomes)• DNA circular• Single celled organisms only
– Eukaryotes• Larger & more complex• Nucleus and organelles present• DNA in long strands• Single or multicellular organisms
Biology Chapter 7 Review
7.2 Eukaryotic Cell Structure – pg174-181• Organelles structure & function
– Cytoplasm– Nucleus
• Nuclear envelope• Chromatin• Chromosomes• Nucleolus
– Ribosomes– ER
• Smooth• Rough
Biology Chapter 7 Review
7.2 Eukaryotic Cell Structure – pg174-181
• Organelles structure & function– Golgi Apparatus– Lysosome– Vacuole– Mitochondria– Chloroplasts– Cytoskeleton
• Note centrioles for coming chapters
Biology Chapter 7 Review
7.3 Cell Boundaries – pg182-189• Cell Membrane
– Lipid bilayer• Hydrophilic & hydrophobic ends• Proteins• Carbohydrates • Fluid mosaic
• Cell Wall– Cellulose– Support/protect cell
Biology Chapter 7 Review
7.3 Cell Boundaries – pg182-189• Diffusion
– Concentration• Equilibrium• Concentration gradient
• Osmosis– How/why water moves
• Hypotonic• Isotonic• Hypertonic
– Effect on cell
Biology Chapter 7 Review
7.3 Cell Boundaries – pg182-189• Facilitated Diffusion
– Protein channels– Move in either direction
• Direction determined by concentration gradient
• Active Transport– Requires energy– Molecular transport– Endocytosis & exocytosis
• Phagocytosis• Pinocytosis
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