Cell Structure & Function
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Transcript of Cell Structure & Function
Cell Structure & Function
Cell Structure & Function
http://koning.ecsu.ctstateu.edu/cell/cell.html
Definition of CellDefinition of Cell
A cell is the smallest unit that is capable of
performing life functions.
A cell is the smallest unit that is capable of
performing life functions.
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Cell Theory
Cell Theory
1. All organisms are composed of cells.
2. Cells are basic unit of structure and function in living things
3. Cells arise only from pre-existing (OLD) cells.
Two Types of Cells
Two Types of Cells
•Prokaryotic•Eukaryotic•Prokaryotic•Eukaryotic
Prokaryote cells are smaller and simpler
Commonly known as bacteria
10-100 microns in size
Single-celled(unicellular) or
Filamentous (strings of single cells)
These are prokaryote E. coli bacteria on the head of a steel pin.
Prokaryotesa. Are generally smaller than eukaryotic cells
b. Have no nucleus
c. Carry out all of life’s processes
d. Ex: bacteria
Eukaryotesa. Are generally larger and more complex than
prokaryotes
b. Contain dozens of membrane bound structures that are specialized
c. Nucleus separates DNA from rest of cell
There are 3 major types of microscopes
1) Light Microscope• Magnifies 40 – 1,000 times depending
on objective being used• Used to magnify objects that light can
pass through.• Uses slides
Exploring the Cell
2) Scanning Electron Microscope
Uses electrons to illuminate objects (3D view)
Can magnify from 30,000 to 9 million times
Mostly large institutions have them
Costly to own and maintain
Can only be used to look at dead specimens
Transmission Electron Microscope
•TEM- thin slices need to be made to have clear images, images are 2-D
•Useful for studying internal structures
Organelles are membrane-bound cell parts
Mini “organs” that have unique structures and functions
Located in cytoplasm
Cell membrane
delicate lipid and protein skin around cytoplasm
found in all cells
Cell Structures
Nucleus
a membrane-bound sac evolved to store the cell’s chromosomes(DNA)
has pores: holes
Nucleolus
inside nucleus
location of ribosome factory
made or RNA
mitochondrion
makes the cell’s energy
the more energy the cell needs, the more mitochondria it has
Ribosomes
build proteins from amino acids in cytoplasm
may be free-floating, or
may be attached to ER
made of RNA
Endoplasmic reticulum
may be smooth: builds lipids and carbohydrates
may be rough: stores proteins made by attached ribosomes
Golgi Complex
takes in sacs of raw material from ER
sends out sacs containing finished cell products
Lysosomes
sacs filled with digestive enzymes
digest worn out cell parts
digest food absorbed by cell
Centrioles
pair of bundled tubes
organize cell division
Cytoskeletonmade of microtubules
found throughout cytoplasm
gives shape to cell & moves organelles around inside.
“Typical” Animal Cell
http://web.jjay.cuny.edu/~acarpi/NSC/images/cell.gif
Structures found in plant cells
Cell wall
very strong
made of cellulose
protects cell from bursting
glued to other cells next door
Vacuole
huge water-filled sac
keeps cell pressurized
stores starch
Chloroplasts
filled with chlorophyll
turn solar energy into food energy
How are plant and animal cells different?
Structure Animal cells Plant cells
cell membrane Yes yes
nucleus Yes yes
nucleolus yes yes
ribosomes yes yes
ER yes yes
Golgi yes yes
centrioles yes no
cell wall no yes
mitochondria yes yes
cholorplasts no yes
One big vacuole no yes
cytoskeleton yes Yes