Microscopes & Cells

Microscopes and Cells: History Don’t copy down this slide – just listen Microscopes and Cells: History In 1663, __________ coined the term “cells” 10 years later, _________________ observed bacteria and protozoa In 1833, __________ observed and coined the term “nucleus” Robert Hooke Anton van Leeuwenhoek Robert Browne

Guten Tag, Dr. Shwann Cell Theory: History Guten Tag, Dr. Schleiden It appears we have come up with a very similar theory… In 1838 (and 1839) German scientists, ________________ & ________________ independently came up with the “Cell Theory” Matthias Schleiden What shall we call this theory? Theodore Schwann

Cell Theory Do you agree? All living things are composed of one or more cells. Cells are organisms' basic units of structure and function. Cells form by free-cell formation, similar to the formation of crystals (spontaneous generation). Do you agree?

all cells must come from pre-existing cells. In 1855, German physician Rudolph Virchow discovered that… all cells must come from pre-existing cells. Please add the above as point #4 to the cell theory

How big are cells? Eukaryotic cells include _______ & _______ cells. Most eukaryotic cells are between __ and ___ m. What is the limit of the light microscope? Why? What is used to see smaller objects? __________________ plant animal 10 100 0.2 m It is limited to the visible light spectrum Electron Microscopes

Electron Microscopy ___________ Electron Microscopes (TEM) emit light through a thin piece of heavy metal ion stained tissue ________ Electron Microscopes (SEM) reflect light off of a piece of heavy metal ion stained tissue Transmission Scanning

Prokaryotic Cells (cells without a nucleus) for ex. bacteria Label this diagram in your handout DNA (Nucleoid) Ribosomes Plasma Membrane Cytoplasm Cilia Cilium Flagella Flagellum TEM of a bacterium

Eukaryotic Cells (cells with a nucleus) Plant cell Animal cell Eukaryotic cells include both plants and animal cells

Differences and similarities between Prokaryotes and Eukaryotes Prokaryotes lack: True nucleus Membrane bound organelles Prokaryotes are much smaller than eukaryotes (prokaryotes are ~1 – 10 m and eukaryotes are 10 – 100 m ) Similarities Both have: DNA Cytoplasm Ribosomes Plasma Membrane

The Plasma Membrane (1) Carbohydrate side chains Proteins Don’t copy down this slide – this is just review Proteins Hydrophilic Region Hydrophobic Region Hydrophilic Region Phospholipid TEM of a red blood cell

The Plasma Membrane (in all cells) It is a semi-permeable barrier that allows for the passage of some things based upon ______, _______, and _____________. size charges solubility in fat

Plasma Membrane’s Microvilli Fingerlike-projections from the cell’s membrane that increase the surface area.

Cell Wall (in plant cells and prokaryotic cells) cell membrane Surrounding the , this 1. provides support 2. protects plant cells and prokaryotes

Cytoplasm (in all cells) The jelly-like fluid that holds all organelles within the cell

Cilia and Flagella (in all cells) Hair-like projections that aide in movement Cilia are shorter, more numerous and move back & forth Flagella are longer & move in a snake-like motion.

Nucleus and nucleolus (in eukaryotic cells) SEM of a freeze-fractured nuclear membrane Nucleus and nucleolus (in eukaryotic cells) _________make ribosomes here: Nucleus holds DNA wrapped around proteins that form ________ ____________, allow things to pass into and out of the nucleus Nucleolus chromatin Nuclear pores TEM of nuclear pores

Ribosomes: (in all cells) Function in protein synthesis (formation) Proteins made by free ribosomes stay in the cell Proteins made by attached ribosomes are shipped out of the cell or sent to the membrane Free ribosomes Attached ribosomes (on ER) TEM of ribosomes Ribosome unit

Endoplasmic Reticulum (in eukaryotic cells) There are two types: ER has ribosomes attached. Modifies & transports proteins ER does not have ribosomes on it. Makes Breaks down carbohydrates Detoxifies drugs & poisons Rough Smooth lipids (fat)

Vesicles (in eukaryotic cells) Organelles that transport proteins from the ER to the golgi and eventually to the plasma membrane

Golgi Apparatus (in eukaryotic cells) _______ carrying protein from the ER move here. Vesicles It sorts, packages, and ships these proteins outside the cell or to the membrane.

Mitochondria (in eukaryotic cells) Cellular Respiration takes place here. It is the “____________” of the cell because it creates energy using oxygen. powerhouse

Chloroplasts (in plant cells) This changes energy from the sun into chemical energy (sugar) in a process is called photosynthesis

The Cytoskeleton (in all cells) 3 types: microtubules, microfilaments, and intermediate filaments

The Cytoskeleton (in all cells) Provides shape and support (skeletal) 2. Moves the organelles within the cell and helps move flagella/cilia Organelle

Centrosome (in eukaryotic cells) and Centrioles (in animal cells only) Centrosomes make microtubules (cytoskeleton). In animal cells, a pair of structures called (made of microtubules) help in cell division. centrioles Centrosome (halo) centrioles

Lysosomes (in animal cells) Special vacuole in animal cells with _________ enzymes that help clean-up the cell Lysosome engulfing a worn-out organelle digestive

Vacuoles (in eukaryotic cells) Large, central organelle in plants Stores water and waste products In animals, it stores food and is small in size compared to plant vacuoles