Bellringer What is a cell? Recall your work yesterday. When classifying cells, what are the two groups scientists separate cells into?

USING A MICROSCOPE Light Microscopes and Total Power Magnification

Uses We can use microscopes to observe cells in greater detail Light microscopes are what we will use in class More complicated microscopes, like scanning and electron transmission microscopes, allow us to see prokaryotic and eukaryotic cell differences in greater detail

Parts of a Light Microscope

Microscope: Total Power Magnification To find this, multiply the power of the objective lens (4X, 10X, 40X), by the power of the eyepiece (usually 10X) Example: A student is viewing a slide using an objective lens with a power of 4X. What is the total power magnification? 4 x 10 = 40X

CELLS Structure and Function of Living Organisms

What is a Cell? A cell is the basic structural, functional, and biological unit of all living organisms “The building block of life” You are made up of about 37 trillion cells!!!

Cell Theory What do we know about cells?

Robert Hooke In 1665, Robert Hooke used an early microscope to look at a thin slice of cork, a plant material. Cork looked like thousands of tiny, empty chambers. Hooke called these chambers “cells.”

Hooke’s Original Sketches

History In 1838, Matthias Schleiden concluded that all plants were made of cells. In 1839, Theodor Schwann stated that all animals were made of cells. In 1855, Rudolph Virchow concluded that new cells were created only from division of existing cells. These discoveries led to the cell theory.

Cell Theory All living things are composed of cells. Cells are the basic units of structure and function in living things. New cells are produced from existing cells.

Types of Cells Prokaryotic Eukaryotic Simple Cells Complex Cells Plant and Animal Cells

Prokaryotic Cells Prokaryotic cells are less complex than eukaryotic cells No membrane bound organelles; smaller Single-celled organisms (ex. Bacteria)

Eukaryotic Cells Eukaryotic cells are complex cells made up of membrane bound organelles Each organelle within the cell carries out different roles Eukaryotic cells make up complex organisms (mostly multicellular)…like insects, fish, and mammals like you!

Prokaryotic vs. Eukaryotic No membrane bound organelles (no mitochondria, nucleus, vacuole, or chloroplasts) Ribosomes DNA and RNA (not enclosed) Circular DNA called plasmids Smaller size Contains membrane bound organelles Ribosomes DNA and RNA (enclosed by membrane) DNA double-helix strands Larger size

Eukaryotic Cells Animal vs. Plant

Animal Cell Nucleus Plasma Membrane Mitochondria Vacuoles Ribosome Cytoplasm Lysosome

Plant Cell Nucleus Plasma Membrane Mitochondria Ribosome Cytoplasm Vacuole (large) Chloroplasts Cell Wall

What differences do you see right away?

Nucleus The “control center” Holds the DNA Dark spot inside nucleus is called the nucleolus (it helps makes the ribosomes) Nucleus

Mitochondria The “powerhouse” of the cell It produces most of the energy for the cell Breaks down food to make ATP ATP is major fuel for all cell activities that require energy Folded inner membrane increase the surface area for energy production during respiration

Plasma Membrane The “gate” of the cell Double membrane structure controls what comes in and out of the cell “YOU SHALL NOT PASS” Plasma Membrane

Ribosome Protein producer The ribosome makes proteins for the cell

Vacuole “Storage tanks” of the cell It stores food, water, and chemicals in the cell Plant cell vacuole is much larger; controls Turgor Pressure-keeps plant upright (no water=wilting) Vacuole

Vacuole in Plants

Cytoplasm Jelly/gel A liquid/gel like substance that surrounds the organelles Cytoplasm

Lysosome (Animal Only) The “garbage cans” Break down and digest waste products using enzymes Lysosome

Cell Wall (Plant Only) “Supporter/protector” The cell wall shapes and protects the plant cell Cell Wall

Chloroplasts (Plant Only) Food producers They are green Contain green chlorophyll and trap energy from the sun for photosynthesis Chloroplast

Organelle Interactions All these organelles work together to keep the cell running!! What do you think would happen if… The Mitochondria or chloroplasts stopped working? The Plasma Membrane didn’t do it’s job? The Nucleus stopped directing activities?

Specialization of Cells Cells all begin as undifferentiated-DNA and genetics play a role in determining the type of cell (ex. nerve cell, muscle, blood…) We will talk more about this later!

Where would you need more… Mitochondria? Chloroplasts? Cell organelles can be more concentrated based on needs!

Question of the Day Which cellular process is most closely related the presence of chloroplasts in eukaryotes? Metabolism Photosynthesis Aerobic respiration Lactic acid fermentation

UNICELLULAR ORGANISMS Structure and Adaptations

Unicellular Organisms A “multicellular” organism is composed of many cells (ex. You are composed of many animal cells; plants are composed of many plant cells) “Unicellular” means they are composed of a single cell! Ex. Bacteria, protozoa, euglena

Structures of Unicellular Organisms Unicellular organisms have many structures that help them survive Contractile vacuoles Cilia Flagella Psuedopods Eyespots

Contractile Vacuoles Stores excess water that enters the cell, and expels it to the exterior It expands when filling with water, then contracts, expelling the contents back out Found in: protists + unicellular algae https://www.youtube.com/watch?v=pahUt0RCKYc

Eyespots A dark area that functions in light reception; influences motion so that the organism can move toward/ away from light Toward (positive phototaxis) Away (negative phototaxis) Found in: green algae; photosynthetic unicellular organisms

Movement Cilia Flagella Many hair like structures https://www.youtube.com/watch?v=QGAm6hMysTA Cilia Many hair like structures Often used for movement Non-motile cilia serve as sensory organelles Flagella Single, whip like tail used for movement Found in: bacteria, protists, specialized plant, animal and fungi cells

Movement https://www.youtube.com/watch?v=PsYpngBG394 Psuedopods “False feet” that help the unicellular organism move about Sometimes used to obtain food (phagocytosis)

Adaptive Behaviors Recall that “taxis” is an innate behavior in response to an outside stimuli

Chemotaxis Movement in response to chemicals (“chemo”). Some single celled organisms direct their movement according to chemicals in their environment Found in bacteria and single-cell or multicellular organisms Find food (e.g., glucose) Flee from poisons (e.g., phenol) Critical to early development

Phototaxis Movement toward or away from light. https://www.youtube.com/watch?v=2koAGkgmiqg Movement toward or away from light. Many plant-like unicellular organisms will move toward light to better photosynthesize, just like plants will tilt toward the window Positive phototaxis: if the movement is in the direction of increasing light intensity Negative phototaxis: if the movement is in the opposite direction of light intensity