Cells

Tissues

Organ systems

Organs

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!)

Charomatin

nucleoid

Prokaryotic Cells are BACTERIA(single cell, no nucleus, no membrane-bound organelles)

Bacteria have 3 BASIC shapes (simple cytoskeleton just inside the

membrane)

http://faculty.ccbcmd.edu/courses/bio141/lecguide/unit1/shape/shape.html

Eukaryotic

Compare the sizes, the line represents 1 mm (1000 nm)

Typical Eukaryotic

Cell

This prokaryotic cellIs similar in size to a eukaryotic organelle

Prokaryoticcell

Virus

Prokaryotes Vs. EukaryotesEukaryotes:

- 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. EukaryotesEukaryotes:

- 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.

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

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.

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

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

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)

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)

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 prefix abbr unit = 1 x ____ meters

Nano n nm 10-9

Micro u or m 10-6

Milli m mm 10-3

Centi c cm 10-2

NO prefix A Angstrom 10-10

What types of microscopes use light?

Which microscopes show “3D”

Which show only black and white

Which would be used to view details of cell organelles?

Which would be utilized to compare ballistics?

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!