cells what did robert hooke call the boxes that he observed in cork?
TRANSCRIPT
Cells
What did Robert Hooke call the boxes that he observed in cork?
Why should I care?
So, what is a cell?
Smallest functional unit that can support
life
A bacterium is only one self-sustaining
cell
You are made up of trillions of
interdependent cells
Too small to see without a microscope
Problem? Miss Apgar wants to view a bacterial cell that
needs to be magnified 1000 times in order to see it. Her compound light microscope has a 10X ocular lens. Which objective lens should she use to see the bacterium?_____________
Where is the ocular lens? ____________________ Where is the objective lens? _________________
What do we remember about microscope history?
Robert Hooke
Named the cell
Cell – Structural and functional unit of life
Made sketches of the
microscopic world
Anton van Leeuwenhoek Perfected a single
lens microscope
Examined water and milk
Called creatures he saw “cavorting wee beasties”
Some More History Matthias Schleiden
Studied plants Determined that all
plants are made of cells
Theodor Schwann Studied animals Determined that all
animals are made of cells
Some More History Rudolf Virchow
German physician Proposed that cells
divide to form new cells
Used his theory to diagnose patients
Father of pathology
Cell Theory - putting their work together
All organisms are made of cells It can be one solitary cell or many cells
working together
The cell is the basic unit of organization in living organisms
Even in complex organisms like humans, the cell is the basic unit of life
All cells come from pre-existing cells Cells grow and divide, passing genetic
information to the next generation of cells
How do we know that cells come from other cells?
Two types of cells… Prokaryotic cells
Simple interior Considered to be the prototype
Eukaryotic cells Complex interior Considered to be the latest update
Prokaryotes Simple interior DNA in central nucleoid region Cellular functions happen in open space Single cell organisms
Bacteria Archaea
Inside a Prokaryote
The cytoplasm is where cell life takes place
DNA is concentrated in the nucleoid region
Ribosomes make proteins
The Flagellum provides transportation
Capsule, cell wall, and cytoplasmic membrane provide protection and support
Eukaryotes Complex interior
DNA is neatly packaged and protected by nucleus
Organelles perform cellular functions
Single and multiple cell organisms Amoebas – single celled
You are a EU-karyote
4 Kingdoms Animalia
Plantae
Fungi
Protista
Inside a Eukaryote
The cytoplasm is where the organelles are located
DNA is housed in the nucleus
Ribosomes make proteins
There are many other organelles each covered by a membrane
Each organelle has its own function
Cytoplasmic membrane provides protection
Venn Diagram Time… turn to page 22!
Prokaryotic Cells
Eukaryotic Cells
Your task now… Look on page 11 in your packet
Read “The Origin of the Eukaryotic Cell” (pgs 19-20)
Answer questions pages 21 and 22
Homework if you do not finish!!
More on the Eukaryote cell
Important
terminology DNA – genetic material
Organelle – cellular
structures that carry out
specific functions
Means “little organ”
Let’s break it down…
First up: the plasma membrane
The Cell Membrane The cell membrane is selectively permeable
Some things can pass but others can’t Cell membranes are made from a phospholipid
bilayer
Phospholipid Bilayer Structure Each phospholipid has a polar head and two
nonpolar tails Polar head is attracted to water Nonpolar tails are repelled by water
Outsideof cell
Insideof cell(cytoplasm)
Cellmembrane
Proteins
Proteinchannel Lipid bilayer
Carbohydratechains
Phospholipid Bilayer Function
Allows some things in and not others
Polar molecules do not easily pass
H2O is an exception because it is small
Keeps the outside out and the inside in
The plasma membrane is always in
motion
Fluid Mosaic Model Fluid
Membrane is in motion Membrane is flexible
Mosaic There are molecules embedded in the bilayer The scattered arrangement looks like a
mosaic
Animal Cells vs. Plant Cells
Eukaryotic cell which makes up tissues in animals
Lack cell walls and chloroplasts, and have smaller vacuoles.
Appears to be circular because of the lack of a rigid cell wall.
Eukaryotic cell that makes up plants
Cell Wall Chloroplast Large Vacuoles
Animal Cell
Plant Cell
Cell Wall Mesh of fibers that surrounds the plasma
membrane Protects and supports the cell Made of carbohydrate, cellulose
Cytoplasm Semi-fluid material inside the plasma
membrane Consists of cytosol and the cellular organelles
(all organelles except the cell nucleus) Cytosol - fluid in which the cellular
organelles are suspended
Cytoskeleton Network of long, thin protein
fibers provide an anchor for
organelles
Microtubules-long hollow
cylinders that assist in
moving substances within
the cell
Microfilaments-thin threads
that give the cell shape and
enable the cell to move Cytoskeleton in Red and Green
Nucleus
Contains genetic material (DNA)
Nuclear envelope
Nuclear pores allow
substances in and out
Nucleolus in center
Very dense center
Ribosomes Produce proteins Made of RNA and protein Made in the nucleolus Some float freely in the cytoplasm Others attach to endoplasmic reticulum
Endoplasmic Reticulum
Interconnected network of tubules
Two types of Endoplasmic Reticulum
Rough ER
Where ribosomes attach and make proteins
Appear to create bumps and rough areas on the membrane
Smooth ER
No ribosomes Produces complex
carbohydrates and lipids
Golgi Apparatus
Modifies, sorts, and packs proteins in sacs called vesicles
Vesicles fuse with plasma membrane
They release proteins which move through membrane to get outside of the cell
Vacuoles Temporary storage for
materials in the cytoplasm
Store, transport, or digest food and waste
Plant cells – 1 large vacuole
Animal cells – several little vacuoles
Lysosomes
Vesicles that contain digestive enzymes to digest excess or worn-out organelles and food particles
They also digest bacteria and viruses that enter the cell
They are built in the Golgi apparatus.
Centrioles Made of Microtubules Found near nucleus Animal Cells only Assembled right before
replication Aid in cell replication
Mitochondria
Powerhouse Converts organic materials into energy
ATP Outer and inner membranes
with lots of folds Provides large surface
area to break sugar molecule bonds (produce energy)
Chloroplasts- Plant only
Capture light energy and convert it to chemical energy through photosynthesis
Photosynthetic Animals 2010 - found an animal that makes proteins
essential for photosynthesis Elysia chlorotica – sea slug that looks like a giant
swimming leaf Stole chloroplasts from algae it eats can live up to 9 months
without eating Appears green because of
stolen chlorophyll
Lives - Eastern coast of the United States and Canada
Cilia and Flagella
Cilia- short, hair-like projections Move back and forth like oars on a rowboat Move substances along surface of the cell
Flagella- rather long hair-like projections Whip-like motion
Both are composed of microtubules
Move cells through watery environment
Cell TransportPassive transport
Does not use energy
Goes with the concentration gradient
3 types diffusion facilitated diffusion osmosis
Active Transport Requires energy Goes against the
concentration gradient Endocytosis Exocytosis
Cell Transport Diffusion -net movement of
particles from high concentration to low concentration Doesn’t require energy
because the particle are in motion passive transport
Dynamic equilibrium- the overall concentration does not change, but molecules are still moving randomly
What affects the rate of diffusion?
What makes molecules move faster? High temperature High Pressure High concentration
Facilitated Diffusion Some ions and molecules can’t diffuse across the
cell membrane Facilitated diffusion – uses transport proteins to
help move some molecules across the plasma membrane
Osmosis
Osmosis – diffusion of waterMost cells undergo osmosis because
they are surrounded by water
Hyper—Hypo– Iso tonic Solutions These are comparing words
Hypertonic -more solute Hypotonic- less solute Isotonic- same solute as
What would happen if you Put a red blood cell in a hypertonic solution? Put a red blood cell in a hypotonic solution? Put a red blood cell in an isotonic solution?
What happens to a red blood cell when…?
Active Transport
Goes from low to high concentration
Requires Energy ATP
Moves large substances
Endocytosis Endocytosis- moving large substances into the cell
Exocytosis
Exocytosis- moving large substances out of the cell
