Introduction to Cytology or Cell Biology

5 Characteristics of Living Things ① Respond to the environment ② Require Energy ③ Grow ④ Reproduce ⑤ Eliminate wastes

How do we observe cells? Light microscope Visible light passes through object Lens magnify image Electron microscope Scanning - surface of object Transmission - sees through objects 100,000 X to Millions magnification power

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 4 Chapter 2 Measurement and Microscopy

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.5 Scale

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 6 Discovery of Microorganisms Antoine van Leeuwenhoek ( ) first to observe and describe microorganisms

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.7 The Compound – multiple lens microscope

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.8

9 Stereoscope

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.10 Microscope Resolution 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? Can they be resolved or separated from each other??

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.11

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.12 Resolving Power

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.13 Resolving Power Resolving power is the ability to make out detail Human Eye  0.1 mm Compound Microscope  0.2 um Electron Microscope  0.5 nm Limitations of Microscopes Light waves scattering causes distortion and unclear images Maximum magnification is about 1500X

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14 Electron Microscopy beams of electrons are used to produce images wavelength of electron beam is much shorter than light, resulting in much higher resolution

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.15 TEMS ---> Ebola Virus

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.16

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.17

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.18

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.19

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 20 Scanning Electron Microscope 3D Images

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.21 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

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.22 Common Dog Flea – Magnified 350X

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.23 Bristle on Common Earthworm – Magnified 350X

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.24 Trypanosome (parasite) next to a red blood cell.

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.25 Fly head

How do we know what happens in each part of the cell? Radioisotopes are used to "trace" different chemical reactions through a cell. Separate cellular structures with a blender Centrifuge material and analyze each layer.

People who were important in early cell discovery:

Robert Hooke (1665) Observed dead cork - called them “cells“ Compound Microscope

Anton Von Leeuwenhoek (1674) - living cells in pond water; one celled organisms -- animalcules

Mattias Scleiden ( 1838 ) stated that plants are made up of cells

Theodor Schwann (1839) stated that animals are made up of cells

Rudolph Virchow (1858) Studied the pathology of cells. (ability to cause disease) 1. All cells arise from preexisting cells. 2. New cells can only arise from other living cells by the process of cell division or reproduction

Cell Theory 1. All living things are composed of cells 2. Cells are the fundamental building block of life 3. All cells come from pre-existing cells (life begets life)

Eukaryotic cells – advanced cells Have nucleus Plasma membrane Cytoplasm - everything between plasma membrane and nucleus Organelles Fluid Cytoskeleton – threads of microtubules and microfilaments in cytoplasm

Animal cells have unique structures Centrioles Lysosome Flagellum Plant cells have unique structures Large central vacuole Cell wall Chloroplasts 3. Animal vs Plant Cell

Mitochondrion Plasma Membrane Cell Wall Central Vacuole Vesicle Ribosomes Envelope DNA Nucleolus Cytoskeleton Fibres Chloroplast Pore Golgi Body Smooth ER Rough sdfER Mitochondrion

Centriole

Plasma Membrane Protein Marker Sugar Chain Lipid Bilayer Cholesterol Proteins Embedded Protein OUTSIDE OF CELL INSIDE OF CELL

Cell Membrane Side Profile

Different membranes 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 Lets some things in or out but not all Like a window screen

Nucleus

Envelope Double membrane Pores to get messages in and out Chromatin DNA threads Protein balls called histones - wrapping Nucleolus - site of ribosome production Nucleus - Structures

Ribosomes

Consists of 2 parts, which are made in nucleus Make protein in the Cytoplasm Produce proteins from ‘recipes’ in the nucleus copied into mRNA 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 Rough ER - attached to nucleus Ribosomes stud surface Produces Membrane proteins - stay in cell Secretory proteins - exported from cell

RER makin’ Proteins!

Golgi apparatus – the Post Office of the Cell

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 Molecules get modified Labeled and / or stored Called the cell “Post office” because it marks and directs products in the cell Golgi apparatus – what it does

Lysosome

Greek for breakdown body Recylcer Sac of strong digestive enzymes Compartmentalized for safety Can release to breakdown entire cell – “suicide sack” Functions Digest food vacuoles Digest invading bacteria Digest old organelles Lysosome

Mitochondria

Site of cellular respiration Conversion of food into energy (ATP) ATP is what cells use to make things happen (drive chemical reactions) Double membrane 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 Mitochondria

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.

Chloroplast 1. chlorophyll is green chemical that releases electrons, working like a solar panel in sunlight 2. forms glucose 3. photosynthesis 6CO 2 + 6H 2 O ---> C 6 H 12 O 6 + 6O 2 Plant Organelles Chloroplasts - in plants

Chloroplasts

Different kinds of cells suited for a different activity. Cell Specialization Division of Labor Different cells divide their labor each has a specific function and supports each other.

1. Cell 2. Tissue 3. Organ 4. Organ system 5. Organism Levels of structure

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 heart Animalsbrain stomach roots Plantsstem leaf

Organ System many organs involved in carrying out a function digestive nervous skeletal excretory respiratory endocrine – (hormones) circulatory muscular reproductive

Organism complete living thing cell tissue organ organ system organism INCREASING SIZE

Prokaryotes 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