Transcript REG BIO Cell Notes

Structure and Function of the Cell
Chapter EIGHT
Cells
• Discovery of cells
made possible with
the discovery of the
microscope
• Def: smallest unit of
matter that can carry
on all the processes of
life
Discovery of the Cell (made possible
by the discovery of scope
– 1665 - Hooke - Discovered
and named the cell –
observed cork – called
them tiny rooms
– 1673 Leewenhoek - First
to see living cells
(microscopic organisms)
Discovery of the Cell
• 1824 – Dutrochet
- Plants and Animals are made of cells
• 1831 - Brown
– Discovered the nucleus
• 1835 - Dujardin
– Discovered protoplasm
• 1838 - Schleiden (botanist)
– Hypothesized all plants were made of cells
Discovery of the Cell
• 1839 - Schwann (zoologist)
– Hypothesized all animals are made of cells
• 1855 - Virchow
– All cells come from other cells
– Discovered that the nucleus controls the cell
Cell Theory
1. All living things are composed of cells
2. Cells are the basic unit of structure and function in all
living
things
organelles
Cell
Tissue
Organs
Organ System
Organism
3. Cells come from reproduction of existing cells
Types of Cells
Eukaryotic
Prokaryotic
 Unicellular
• Multicellular and
unicellular
 No nucleus
• Nucleus present
 No membrane
• Membrane
bound
organelles
bound organelles
 Most numerous of
living things
 Ex: bacteria, protista
• Ex: animals,
plants, fungus,
algae
Cell Shape
• The shape of the cell (form) reflects its function.
• Ex: Nerve cell are long strands for sending chemical messages
throughout the body.
• Ex: Blood cells are circular and pliable to get through the
blood vessels.
Cell Shape- “Skin Deep”
• Skin Deep
Cell Size
 10-50 um (micrometers)
 Limited by its surface area to volume ratio
Lipid bilayer
• Contain a phosphate
head that is polar and
soluble in water
• Has a fatty acid tail
that is nonpolar and
insoluble in water
Parts of the Cell
 Cell (Plasma) Membrane
◦ Semipermeable - keeps some
molecules out, but lets others
through (controls what enters
and leaves cell
◦ Made of a lipid bilayer
◦ Has protein channels that aid
with the movement of
nutrients, water, oxygen into
the cell and waste and CO2 out
of the cell
◦ Have carbohydrate chains
which are chemical recognition
sites and interact with each
other
Fluid Mosaic Model
 Fluid: Membrane
bilayer acts as liquid
(lipids and proteins
move within bilayer)
 Mosaic: made of
several different
components
 Ex’s: nuclei, vacuoles,
mitochondria, and
chloroplast
Cytoplasm
• contains water and
salts
• between cell
membrane and the
nucleus
• Site of chemical
reactions
Nucleus and Nucleolus
 Nucleus directs all
activity of the cell;
such as cell growth,
protein synthesis, cell
division
 Nucleolus is a dark
dot in the nucleus
makes ribosomes and
stores proteins and
RNA
Nuclear Envelope or Nuclear
Membrane
• Double membrane
where substances
enter and leave
through pores
(nuclear pores)
Cell Wall
 Located outside cell
membrane, has pores
 Supports and protects
plant
 Made of cellulose
 Nonliving
 Plants, fungus,
bacteria
Vacuole
• Large fluid filled
membranous sac
• Stores , enzymes,
metabolic wastes
• Pressure of water
keeps plants from
wilting
Plastids
• Have 2 membranes
• Function- store energy in sugar molecule bonds
• Types…
Plastids (plants only)
• Chromoplast
– Pigments for red,
orange, and yellow
color fruit, flowers,
leaves
• Chloroplasts
– Contain chlorophyll
(green) trap sunlight
for photosynthesis
Leucoplast
• Found in plants
• Colorless
• Starch storage
Ribosomes
 Make proteins and
enzymes
 Found free floating in
the cytoplasm and
attached to the
endoplasmic
reticulum
 Has no membrane
 In Eukaryotic and
Prokaryotic cells
Endoplasmic Reticulum
 FUNCTIONS
Makes protein and enzymes
makes steroids (gland cells)
regulates calcium levels in muscle
breaks down toxic substances in
the liver
 Rough ER - has ribosomes
 Smooth ER - has NO ribosomes
stores what the RER makes
Golgi Apparatus/Golgi Complex
 Add lipids or
carbohydrates to
proteins made by
rough ER and
ribosomes
 Golgi then package
the finished proteins
and transports them
for export
Lysosomes
 Small sacs of
powerful digestive
enzymes which
cleans up cellular
wastes by
dissolving them
 Made by golgi
Centrioles
• Rod shape
structure
• Used during
mitosis and is
responsible for
spindle formation
and movement
• Animals only
• Made of
microtubules
Cytoskeleton
 Called microtubules
 Hollow tubes that
support cells and
move cells
 Maintains shape and
size of cell
 Microfilaments:
protein fibers used to
move organelles and
used in muscle
contractions
Cilia/Flagella
•
•
•
•
Hair like organelle for movement
Cilia-many and short
Flagella-few and long -tail like
Made of microtubules
Flagella and Cilia Movement
Mitochondria
 Provide energy for the
cell by converting
glucose and oxygen
into A.T.P.(energy
molecule)
 Called the
powerhouse of the
cell
 Cristae increases
surface area for
chemical reactions
Chromatin
 Fine strands
 Combination of DNA
and protein
 Located in nucleus
 When tightly packed
they are called
chromosomes
 Stores heredity info
Differences Between Plants and Animals
• Animals have centrioles, many small vacuoles,
• Plants have cell walls, large central vacuole, and
chloroplasts
Cell Action
• Harvard 3D animation