Download Eukaryotic Cell Parts

THE CELL
Introduction to
Cell History

Robert Hooke – 1665
Observed slices of cork
 Coined word “cell”


Anton van Leeuwenhoek - 1673
First to observe living cells (algae)
 “animalcules”


1821-1902
Schleiden – plants
 Schwann – animals
 Virchow – cell reproduction

Cell Theory
1.
2.
3.
All living things are made of one or more cells
Cells are the basic units of structure and function in
organisms
All cells arise from existing cells
Why are cells important?
Gas Exchange
 Eat
 Make energy (ATP)
 Build molecules

 proteins,
carbohydrates, fats, nucleic acids
Remove wastes
 Maintain homeostasis
 Reproduce

Cell Size

Can’t be seen with the naked eye
Human body = ~100 trillion cells
http://www.youtube.com/watch?v=l7kZjdeo0Cs
http://www.cellsalive.com/howbig.htm

Cell Size Activity



Why so small?!


A small cell has a greater ratio of surface area to volume
The microscopic size of most cells ensures a sufficient
surface area
 Across which nutrients and wastes can move to service the
cell volume
10 m
30 m
Surface area
of one large cube
 5,400 m2
30 m
10 m
Total surface area
of 27 small cubes
 16,200 m2
Intro Video

https://www.youtube.com/watch?v=URUJD5NEXC8
Cell Types


Prokaryotic – single celled organisms that lack a
nucleus
Eukaryotic – cells with a nucleus and internal
compartments
 micron = micrometer = 1/1,000,000 meter
 diameter of human hair = ~20 microns
Common Features

Cytoskeleton
Prokaryotic cells





Simple, single-celled organisms
All have cell walls
Many have flagella or pili
Some have capsules
Ribosomes
Ex. Bacteria
Prokaryotic
flagella
Capsule
Cell wall
Plasma
membrane
DNA
Pili
Eukaryotic cells
Nucleus
 Organelles – differentiated structures within the cell
 Complex, multicellular organisms

Cell Membrane

Functions:
 Selectively
permeable – regulates what goes in
and out of cell
 Protection
 Controls the internal environment
 Provides shape

Structure:
 Phospholipid
bilayer
 Transport proteins
Cell Membrane (cont.)

Fatty acid tails
 Hydrophobic

– water fearing
Phosphate head
 Hydrophilic
– water loving
Fluid Mosaic Model
Transport



Passive Transport: particles pass across the cell
membrane freely
Active Transport: particles cross the cell
membrane with the use of energy
https://www.youtube.com/watch?v=ufCiGz75DA
k
Diffusion



Concentration: the amount of a particular
substance in a given volume.
Substances naturally move from a higher
concentration to an area of lower concentration
Equilibrium: is reached when a space is filled
evenly
Osmosis


When water is diffused across the cell membrane
It is important for a cell to maintain water balance
as their environment changes
Solution Types



Hypotonic – less molecules outside cell
Isotonic – equal molecules on both sides of the
membrane
Hypertonic – more molecules outside cell
Lower
concentration
of solute
Solute
molecule
Equal
concentration
of solute
Higher
concentration
of solute
H2O
Selectively
permeable
membrane
Water
molecule
Solute molecule with
cluster of water molecules
Net flow of water
Isotonic solution
H2O
Hypotonic solution
H2O
H2O
Hypertonic solution
H2O
Animal
cell
H2O
Plant
cell
H2O
H2O
H2O
Cytoplasm



The area between the nucleus and plasma
membrane
Holds organelles
Cytosol – fluid between the organelles
Ribosomes

Protein synthesis
 read
instructions to build proteins from DNA
 Found in all organisms!
EUKARYOTIC CELL PARTS
Review



Ribosomes
Cytoplasm
Cell Membrane
Nucleus




Function: Directs activities of the cell
Protects genetic information (DNA)
Controls the cell's growth and reproduction.
Parts:
 Nuclear
Envelope
 Nucleolus
 Chromatin
 Nuclear Pores
Compartmentalize


Organelle - differentiated structures within the cell
Advantage:
 Allows
the cell to accomplish more metabolic processes
 Incompatible activities can happen at the same time
Endoplasmic Reticulum


“network within the cell”
2 parts
 Rough
Endoplasmic Reticulum (RER)
 Embedded
with ribosomes
 Synthesizes and modifies proteins
Endoplasmic Reticulum cont.
 Smooth
Endoplasmic Reticulum (SER)
 Embedded
with enzymes
 Synthesizes lipids
 Processes toxins and drugs in liver cells
 Stores and releases calcium ions in muscle cells
Vesicles


Used for transportation within the cell
Buds off of ER and Golgi Body
Golgi Apparatus

Modifies, packages, and ships cell products that
come from the ER or ribosomes
Lysosomes & Peroxisomes

Lysosomes
 Contains
digestive enzymes to break down nutrients,
bacteria, and wastes
 Not present in most plant cells

Peroxisomes
 Breakdown
Hydroxide (H202) by-product
Rough ER
1
Transport vesicle
(containing inactive
hydrolytic enzymes)
Golgi
apparatus
Plasma
membrane
Lysosome
engulfing
damaged
organelle
2
Engulfment
of particle
“Food”
Lysosomes
3
Food
vacuole
4
5
Digestion
Mitochondria



Location for cellular respiration
Converts the chemical energy of foods into ATP
Double membrane layer
Cytoskeleton

The cell’s internal skeleton helps organize its
structure and activities
A
network of protein fibers
Tubulin subunit
Actin subunit
Fibrous subunits
25 nm
10 nm
7 nm
Microfilament
Intermediate filament
Microtubule
Centrioles

Main function is to produce and organize the
cytoskeleton during cell reproduction
Animal Cell
Plant Cell
Cell Wall

rigid boundary made largely of cellulose for
support and environmental resistance
Not in
animal
cells
Central
vacuole
Chloroplast
Cell wall
Central Vacuole
Main function: Store water
 Contains
enzymes – equivalent to animal lysosomes
 Holds pigments for flower color
Nucleus
Chloroplast
Central
vacuole
Colorized TEM 8,700

Chloroplast



Converts light energy into chemical energy
Only in plants and some protists
Chlorophyll = green pigment
Not in
animal
cells
Central
vacuole
Chloroplast
Cell wall
Rough
endoplasmic
reticulum
Smooth endoplasmic
reticulum
Nucleus
Flagellum
Not in most
plant cells
Lysosome
Ribosomes
Centriole
Peroxisome
Microtubule
Cytoskeleton
Intermediate
filament
Microfilament
Golgi
apparatus
Plasma membrane
Mitochondrion