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