Transcript Intro to Cells Powerpoint 2011

Cells
Tissues
Organs
Organ systems
Organisms
 1665
– Robert Hooke observes
cork is made of little
compartments he calls “cells”
 1674 – Leeuwenhoek observes
living cells for the first time animalcules
 1838 – Schleiden determines all
plants are made of cells
 1839 – Schwann determines
animals are made of cells
 1850
– Brown discovers the
dense centers of certain cells
and names the nucleus
 1855 – Virchow discovers cells
make more cells
 All
living things are made up of
one or more cells
 Cells are the basic unit of
structure and function in living
things
 Cells come from previously
existing cells – NO spontaneous
generation!
There are two major types of cells:
Prokaryotes: literally means “before
nucleus”
- primitive single celled life, the first!
- example: bacteria
- DNA found in cytoplasm (nucleoid)
- no membrane bound organelles
- extremely small (even for a cell!)
nucleoid
Charomatin
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Prokaryotic Cells are BACTERIA
(single cell, no nucleus, no membranebound organelles)
Bacteria have 3 BASIC shapes
(simple cytoskeleton just inside the
membrane)
http://faculty.ccbcmd.edu/course
s/bio141/lecguide/unit1/shape/s
hape.html

Eukaryotic
Typical
Eukaryotic
Cell
This prokaryotic cell
Is similar in size to a
eukaryotic organelle
Prokaryotic
Virus
cell
Compare the sizes, the line represents 1 mm (1000 nm)
Prokaryotes Vs. Eukaryotes
Eukaryotes:
- literally means “true nucleus”
- DNA enclosed by the nuclear membrane
- Can be single celled like protists (amoebas,
paramecium)
- Or can be part of a multicellular organism like:
plants, animals or fungi
Prokaryotes Vs. Eukaryotes
Eukaryotes:
- significantly larger than prokaryotic cells
- have many more organelles than
prokaryotic cells

The membrane system in a eukaryotic cell is connected.

The nucleus is connected to the ER. Smoothe ER is
connected to rough ER,

ER is connected to the cell membrane

Vesicles can be formed by any membrane bound
organelle or by the cell membrane.

Vesicles transport food, enzymes and waste

Cell Wall and Cell Membrane

Vacuoles – Large and small

Lysosomes and Vacuoles

Centrioles vs no Centrioles

Mitochondria vs. Chloroplasts.
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Cell pictures show a cell with “all organelles.

In reality, some cells have more of some
organelles than others.

Some organelles are not present in some cells
or present in small quantities (like Smooth ER),
but are present in specialized cells (like liver
cells).

Liver cell
◦ Synthesizes lipids
◦ Metabolizes drugs and toxins

Enucleated RBC
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All cells must perform certain tasks to stay
alive
Just how they go about it might be a little
different depending on what organelles they
have to work with.
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Be able to list the functions of all organelles
Describe why these jobs are important to
survival of the cell
Describe how different cells accomplish these
tasks
Compare and contrast the differences
between cell types!

Note Cilia

How do we see animalcules and other small
organisms (and parts of organisms).

Tools
◦ Objects used to improve the performance of a task

Microscopes
◦ Extend human vision by enlarging, with high
resolution, things that might be impossible to see.

Use light (photons) to view specimens
◦ Two types
◦ Stereo (dissecting) microscope
 40x – 70x magnification (in general)
 3D view (two eye pieces)
 Live specimens can be viewed, but often used to
compare two things (ballistics, etc)
◦ Compound Light Microscope
 Magnifies using two lenses – 1000x – 2000x
 Thick objects must be sliced thin enough so that
light passes through
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Gather light from the tiny area where a
specimen is located (thinner  more light
transmitted)
Image is brought into focus by the objective
lens (in a fairly short distance), then
magnified by a second lens (the eye piece)
Resolution and magnification from the
objective lens, magnification only from the
eyepiece.

Magnification
◦ Increase in an object’s apparent size.
◦ Calculated in light microscopes by multiplying the
magnification of each of the lenses

Resolution
◦ Minimum distance between two objects at which the
objects can just be determined as separate. Depends on
the wavelength of the light and the light gathering
capability of the lens. (cannot go > 2000x; most 1000x
◦ Dmin = 1.22 x wavelength / N.A.
objective
+ N.A.
condenser
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A beam of electrons enlarged image
Higher magnification (up to 2,000,000x)
and resolution (use electrons rather than
photons) than light microscopes
Always black and white (color is added by
computer, electrons do not emit a color)
Always dead (specimen must be in a
vacuum chamber so… no air)
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Surface scanning
3D
Gold coated and electrons are “fired” at the
metal coating (metal emits other electrons
and these are projected onto a photographic
plate (100,000 – 200,000x)
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Transmits electrons THROUGH a very thinly
sliced specimen
Magnetic lenses enlarge the image (focuses
charged particles rather than a light image)
Magnification 200,000x to 2,000,000x
(this number may vary depending on the
source)

Metric system
◦ Consists of base unit
 Length = meter (m)
 Mass = gram (g)
 Volume = liters (l)

We will use units of length (meters) to
describe the size of organisms
Prefix
 Nano
 Micro
 Milli
 Centi

prefix abbr
n
u or m
m
c
NO prefix
A
unit
nm
mm
mm
cm
Angstrom
= 1 x ____ meters
10-9
10-6
10-3
10-2
10-10
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What types of microscopes use light?
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Which microscopes show “3D”

Which show only black and white
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Which would be used to view details of cell
organelles?
Which would be utilized to compare ballistics?
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Read information on the first pages. Fill in
the “blanks” on the microscope, use your lab
to help with this
Answer questions on second page, be sure to
think about the characteristics of viruses vs.
living things!