Transcript Cells - Bishop Ireton High School

Cells
Unit 3
Development of Cell Theory



Anton van Leeuenhoek -1600’s ,developed
1st microscope. Saw tiny things in a drop of
water.
Robert Hooke- looked at cork. Saw tiny
squares that looked like the monks roomscalled them cells. Actually saw the plant cell
wall.
Robert Brown- first to see cell nucleus



Matthias Schleiden- proved all plants were
made of cells
Theodor Schwann- proved all animals made
of cells
Rudolf Virchow- showed that cells come from
other cells dividing.
Ideas led to………
The Cell Theory



All living things composed of cells
Cells are basic unit of structure
All cells come from pre existing cells.
Microscopes




Compound Light M.- uses light. Can magnify
up to 1000x.
Electron microscopes- uses beam of
electrons. Specimen must be viewed in
vacuum( no air- so specimen dead!)
Scanning EM- scans the surface- gives 3D
picture
Transmission EM- can see inside cell.
2 Types of cells


Prokarotes
Eukaryotes
Prokaryotes


Do not have membrane bound organelles: no
nucleus.
Bacteria
Eukaryotes


Have membrane bound organelles: like a
nucleus.
Animal cell, plant cell
Cell structure

Cells come in many different sizes and
shapes because of the function they carry
out.
Properties of All Cells




Obtain food for energy
Excrete wastes
Make new living material(growth)
Reproduce
Plasma Membrane
Function


Controls the internal environment of a celldecided what moves in and out
Maintains homeostasis
Selective permeability


allows some molecules to pass through
membrane (SEMI PERMEABLE)
Molecules can pass through membrane or
pass with aid from membrane proteins

PHOSPHOLIPID(sub
unit)
Glycerol + 2 FA
chains+P
Phosphate head
Fatty Acid tail

Hydrophilic head
Hydrophobic tail
Structure
Fluid Mosaic Model



Phospholipid bilayer- 2 rows of phospholipids
with the tails facing each other
Phospholipids moveable
Mosaic- made of different partsMembrane proteins-transport materials
through,also act as cell receptors for
recognition
Cholesterol-helps keep fatty acid tails
from sticking together- helps maintain fluidity
ORGANELLES
Cell structure with a
specific function and
shape
CELL WALL
•Found
in plant cells
•Provides rigidity and
strength
•Made of cellulose
•Pectin glues the
cells together
NUCLEUS
•Controls
cell functions
•Surrounded by nuclear
membrane(has pores)
•Contains DNA (chromatin )
has instructions(genes) for
all cell metabolism like
making proteins
•Chromosomes are made of
long strands of chromatin
that are condensed
NUCLEOLUS
•Found
inside
the nucleus
•Makes
ribosomes
RIBOSOMES
•Site
of protein
production
•Not membrane
bound
•Found in the
cytoplasm(free)
•And also on the
RoughER (bound)
•Made
of RNA
CYTOPLASM
•Clear
gelatinous
fluid inside cell
•Suspends the
organelles
•Site of metabolic
reactions
ENDOPLASMIC
RETICULUM
•Folded
membrane
•Rough ER has ribosomes
attached-make proteins
that are used oustide of the
cell
•Unbound ribosomes make
proteins used inside the
cell
Act as transport channels
to move material within the
cell
Packages proteins in small
vessicles to move to Golgi
Golgi
Apparatus
•Flattened
stack of
membranes
•Modifies proteinsspecializes them
•Packages proteins
so they can leave
the cell
VACUOLES
•Compartments
used
for temporary storage
•Can store waste, food,
enzymes
•Plant cell has 1 large
vacuole to store water
Plastids
•Found
in plants
•Used to store food and
pigments
•Plastid that store pigment
is a chromoplast
•(chlorophyll/chloroplast)
LYSOSOME
•Only
found in animal cells
•Contains digestive enzymes
•Digest worn out cell parts, food,
engulfed bacteria and viruses
•Membrane surrounding
lysosome prevents leakage of
digestive enzyme into cytoplasm
where it would self- digest the
cell
•Can fuse with food vacuole to
digest food.
•What
would happen to a cell if the
lysosomes burst?
CHLOROPLAST
•Only
found in plant cells
•Capture light energy
and turn it into chemical
energy
•Contains chlorophyll
•3 parts:
thylakoid-disc
granum-stack
stroma-inner space
MITOCHONDRIA
•Power
house of the cell
•Makes ATP
•Adenosine Triphosphate
•# of mitochondria depend on
energy needs of cell-ex.
Muscle cells have a lot!
•Glucose is changed to ATP at
the inner folds(cristae)
•Cellular Respiration
CYTOSKELETON
Microtubules and Microfilaments
•Microtubules-
hollow
•Microfilaments- solidfunction in cytoplasmic
streaming
•Made of proteins
•Provide internal support
•Acts like scaffold
•Also like a highway in the
cell to move materials
Centrioles
•Found
in animal
cells only
•Aids in forming
the spindle fibers
used during cell
division(mitosis)
•Made of
microtubules
CILIA AND
FLAGELLA
•Made
of microtubules
•Cilia- short hair like
fibers used for
locomotion
(paramecium)
•Flagella- long whip
like structure used for
locomotion
THE CELL
Transportation of
Materials
Movement of Materials
The cell membrane is SEMI PERMEABLE:
allows movement of some things in and out
 Diffusion- movement of materials across a
membrane
 Osmosis- movement of WATER across a
membrane


Cells want to be at equilibrium(Homeostasis)
TYPES OF DIFFUSION



PASSIVE- requires no energy- moves high to
low
FACILITATED- membrane proteins or carrier
molecules help materials cross the
membrane. They can’t cross on their own.
ACTIVE- energy required- moves low to
high(you are pushing more into the cell)
PASSIVE DIFFUSION
FACILITATED DIFFUSION
ACTIVE DIFFUSION



Hypotonic- cell or solution has less
molecules
Hypertonic- cell or solution has more
molecules
Isotonic- cell or solution has equal molecules
Animal Cell
Type
Movement of
Water
Fate of Cell
HYPOTONIC
Into cell
Cell swells and
bursts
HYPERTONIC
Out of Cell
Cell shrinks and
shrivels
LYSES
ISOTONIC
No net change
HOMEOSTASIS
Picture
ANIMAL CELL
PLANT CELL
Movement of large material across cell
membrane-requires energy
 Endocytosis-
cell surrounds
material and
engulfs it.
Phagocytosis: taking in a solid
Pinocytosis: taking in a liquid
EXOCYTOSIS
cell expels material
1. Material contained in a
vacuole
2. Vacuole moves toward outer
edge
3. Vacuole opens up to outside
and releases material