Transcript Skeletal muscle cells

Introduction to
Cytology or Cell Biology
5 Characteristics of Living Things
①
②
③
④
⑤
Respond to the environment
Require Energy
Grow
Reproduce
Eliminate wastes
How do we observe cells?
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Light microscope
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Visible light passes through object
Lens magnify image
Electron microscope
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Scanning - surface of object
Transmission - sees through objects
100,000 X to Millions magnification power
Chapter 2
Measurement and Microscopy
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4
Scale
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Discovery of Microorganisms

Antoine van
Leeuwenhoek
(1632-1723)
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first to observe
and describe
microorganisms
6
The Compound – multiple lens
microscope
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Stereoscope
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Microscope Resolution
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ability of a lens to separate or distinguish small
objects that are close together
wavelength of light used is major factor in
resolution
shorter wavelength  greater resolution
At what point are the dots separate?
they be resolved or separated
from each other??
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Resolving Power
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Resolving Power

Resolving power is the ability to make out detail
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Human Eye
 0.1 mm
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Compound Microscope
 0.2 um
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Electron Microscope
 0.5 nm

Limitations of Microscopes

Light waves
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 scattering
causes distortion and unclear images
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 Maximum
magnification is about 1500X
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Electron
Microscopy


beams of electrons
are used to produce
images
wavelength of
electron beam is
much shorter than
light, resulting in
much higher
resolution
14
TEMS ---> Ebola Virus
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Scanning Electron Microscope
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3D Images
20
The Scanning Electron
Microscope


uses electrons reflected from the
surface of a specimen to create image
produces a 3-dimensional image of
specimen’s surface features
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Common Dog Flea – Magnified
350X22
Bristle on Common Earthworm
– Magnified 350X
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Trypanosome (parasite) next
to a red blood cell.
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Fly head
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How do we know what
happens in each part of the
cell?

Radioisotopes are used to "trace" different
chemical reactions through a cell.
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Separate cellular structures with a blender
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Centrifuge material and analyze each layer.
People who were important in
early cell discovery:
Robert Hooke (1665)
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Observed dead cork - called them
“cells“
Compound Microscope
Anton Von Leeuwenhoek
(1674)
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- living cells in pond water; one celled
organisms -- animalcules
Mattias Scleiden (1838)
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stated that plants are made up of cells
Theodor Schwann (1839)
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stated that animals are made up of
cells
Rudolph Virchow
(1858)
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1.
2.
Studied the pathology of cells. (ability to cause
disease)
All cells arise from preexisting cells.
New cells can only arise from other living
cells by the process of cell division or
reproduction
Cell Theory
1.
2.
3.
All living things are composed of
cells
Cells are the fundamental building
block of life
All cells come from pre-existing cells
(life begets life)
Eukaryotic cells – advanced cells
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Have nucleus
Plasma membrane
Cytoplasm - everything between plasma
membrane and nucleus
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Organelles
Fluid
Cytoskeleton – threads of microtubules
and microfilaments in cytoplasm
Animal vs Plant Cell
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Animal cells have unique structures
 Centrioles
 Lysosome
 Flagellum
1.
2.
3.
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Plant cells have unique structures
 Large central vacuole
 Cell wall
1.
 Chloroplasts
3.
2.
Cytoskeleton Fibres
Mitochondrion
Mitochondrion
Chloroplast
Vesicle
Golgi Body
Central
Vacuole
Smooth
ER
Rough
sdfER
Cell
Wall
Plasma
Membrane
Nucleolus
Pore
DNA
Envelope
Ribosomes
Centriole
Plasma Membrane
OUTSIDE OF CELL
Sugar Chain
Lipid Bilayer
Protein Marker
Cholesterol
INSIDE OF CELL
Proteins
Embedded
Protein
Cell Membrane Side Profile
Different membranes
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All have similar functions & structures
Plasma membrane separates inside of cell from
outside of cell
Other membrane define organelles to form
compartments of eukaryotic cells
Forms a selectively permeable layer
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Lets some things in or out but not all
Like a window screen
Nucleus
Nucleus - Structures
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Envelope
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Chromatin
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Double membrane
Pores to get messages in and out
DNA threads
Protein balls called histones - wrapping
Nucleolus - site of ribosome production
Ribosomes
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Consists of 2 parts, which are made in nucleus
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Make protein in the Cytoplasm
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Produce proteins from ‘recipes’ in the nucleus
copied into mRNA
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Some (proteins) will remain in cytoplasm
Some will be exported out of cell
Some will attach to membranes in cell
Ribosomes are found on the endoplasmic
reticulum and in the cytoplasm
Endoplasmic Reticulum
Rough
ER
Smooth
ER
Rough Endoplasmic Reticulum
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Rough ER - attached to nucleus
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Ribosomes stud surface
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Produces
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Membrane proteins - stay in cell
Secretory proteins - exported from cell
RER makin’ Proteins!
Golgi apparatus – the Post
Office of the Cell
Golgi apparatus – what it does
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Refines, stores and marks molecules for
shipment
Looks like stack of hollow pancakes
Products of ER arrive & leave via transport
vesicles
Moving from one sac to the next
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Molecules get modified
Labeled and / or stored
Called the cell “Post office” because it marks
and directs products in the cell
Lysosome
Lysosome
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Greek for breakdown body
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Sac of strong digestive enzymes
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Recylcer
Compartmentalized for safety
Can release to breakdown entire cell – “suicide
sack”
Functions
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Digest food vacuoles
Digest invading bacteria
Digest old organelles
Lysosome
Mitochondria
Mitochondria
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Site of cellular respiration
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Conversion of food into energy (ATP)
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Double membrane
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ATP is what cells use to make things happen (drive
chemical reactions)
Big bag stuffed in smaller bag
Folds of inner bag called cristae
Space inside inner bag called matrix
Also once free living bacteria
Efficiency - gasoline engines converts 25% of energy
mitochondria converts 54% of energy
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contains some of its own DNA (amount
varies within organisms)
believed to evolved from a primitive
cell engulfing it and creating a
symbiotic relationship
DNA in mitochondria obtained only
from mother of organism.
Plant Organelles Chloroplasts - in
plants
Chloroplast
1. chlorophyll is green chemical that releases
electrons, working like a solar panel in sunlight
2. forms glucose
3. photosynthesis
6CO2 + 6H2 O ---> C6H12 O6 + 6O2
Chloroplasts
Cell Specialization
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Different kinds of cells suited for a
different activity.
Division of Labor
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Different cells divide their labor each
has a specific function and supports
each other.
Levels of structure
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1.
2.
3.
4.
5.
Cell
Tissue
Organ
Organ system
Organism
Tissue Level
A group of cells that are alike in structure and
activity in an organism muscles
- Skeletal muscle cells – motion
- Cardiac muscle cells – heartbeat
- Bones - support
- Nerve cells - coordination, perception
and automatic body functions
Organ Level
several tissues working as a unit
Animals
heart
brain
stomach
Plants
roots
stem
leaf
Organ System
many organs involved in carrying out a function
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digestive
nervous
skeletal
excretory
respiratory
endocrine – (hormones)
circulatory
muscular
reproductive
Organism
complete living thing
cell
tissue
organ
organ system
organism
Prokaryotes
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Cells that do not have a
nucleus
Exist almost every where on
earth
Grow in numbers so great
you can see them with the
unaided eye
Eukaryotic vs Prokaryotic Cells
What are Viruses
A virus is a non-cellular particle made
up of genetic material and protein
that can invade living cells.
T4 Bacteriophage
Herpes Virus
E. Coli and the
Bacteriophage
What it looks like in real life