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

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

Light Microscopes and Total Power Magnification

We can use microscopes to observe cells in greater detail Light microscopes are what we will use in class More advanced microscopes, like scanning and electron transmission microscopes, allow us to see prokaryotic and eukaryotic cell differences in greater detail Think about it: How does an electron microscope work? Why are these microscopes so expensive? -A beam of electrons is scanned over a surface to create an image. They are larger, and more expensive to build and maintain!

To find this, multiply the power of the objective lens (4X, 10X, 40X), by the power of the eyepiece (usually 10X) Think about it: 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

Structure and Function of Living Organisms

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!!!] Think about it: How do a human and an elephant differ? The elephant has more cells because it is larger, but the cells themselves are not bigger!

What do we know about cells?

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.

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.

1. All living things are composed of cells. 2. Cells are the basic units of structure and function in living things. 3. New cells are produced from existing cells.

1. Which part of the microscope would you adjust to increase the magnification of a slide? 2. A student is viewing a slide using an objective lens with a power of 10X. What is the total power magnification? 3. What does the cell theory tell us about cells?

1. What is a cell? What does cell theory tell us about cells? 2. Think about what you know about cells. Name 5 organelles and their functions!

Prokaryotic Simple Cells Eukaryotic Complex Cells Plant and Animal Cells

Prokaryotic cells are smaller and less complex than eukaryotic cells No membrane bound organelles; smaller Single-celled organisms (ex. Bacteria) Contains: Single, circular DNA; ribosomes; cell membrane

Eukaryotic cells are larger, 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 No membrane bound organelles (no mitochondria, nucleus, vacuole, or chloroplasts) Ribosomes One strand of circular DNA not enclosed in a nucleus Additional circular DNA (plasmids) can be present Smaller size EUKARYOTIC Contains membrane bound organelles Ribosomes DNA (enclosed by membrane) DNA double-helix strands Larger size

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

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

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 Mitochondria

Think about it: Which cells would need a lot of mitochondria? Think about it: What would happen if the cell lost all of its mitochondria?

The gate of the cell Double membrane structure controls what comes in and out of the cell YOU SHALL NOT PASS (without permission!) Plasma Membrane

Protein producer The ribosome makes proteins for the cell Can be attached to the ER or free floating in the cytoplasm Ribosome

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

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

The garbage cans Break down and digest waste products using enzymes Lysosome Think about it: what would happen to the cell if all of the lysosomes burst at the same time? Does this every happen on purpose?

Supporter/protector The cell wall shapes and protects the plant cell Think about it: What is the plant cell made of? (Hint: What substance do plants make during photosynthesis?) Cell Wall

Food producers They are green Contain green chlorophyll and trap energy from the sun for photosynthesis Glucose (sugar) producers Produce enough ATP to fuel photosynthesis Chloroplast

All these organelles work together to keep the cell running!! Think about it: What do you think would happen if The Mitochondria or Chloroplasts stopped working? The Plasma Membrane didn t do its job? The Nucleus stopped directing activities?

Create a Venn diagram comparing eukaryotic and prokaryotic cells.

1. How are prokaryotic and eukaryotic cells similar? a) Both contain a nucleus b) Both contain ribosomes c) Both contain membrane-bound organelles d) Both contain cell walls 2. This diagram shows a plant cell. Which structure is found in a plant cell but absent in an animal cell? a) 1 b) 2 c) 3 d) 4

Identify the following descriptions as plant, animal or both: 1. Contains a cell membrane 2. Contains chloroplasts 3. Contains mitochondria 4. Contains lysosomes 5. Contains a nucleus

Label the parts of the cell: 1. 4. 5. 6. 8.

Which cellular process is most closely related the presence of chloroplasts in eukaryotes? a) Metabolism b) Photosynthesis c) Aerobic respiration d) Lactic acid fermentation

Nucleus Brain of the cell -controls cell functions and stores DNA Mitochondria Powerhouse of the cell -makes energy through cellular respiration; folded inner membrane provides lots of surface area for cell processes Cell membrane Gate of the cell -Double membrane structure composed of lipids-controls what goes in and out

Ribosomes Site of protein synthesis (makes proteins); attached or free floating Cytoplasm Jelly/gel that surrounds cells-keeps organelles where they should be Vacuole Storage center -holds water, food, etc.-large in plants due to Turgor Pressure

Chloroplast Plants only-uses sunlight to convert to sugar through process of photosynthesis Cell wall Plants only-carbohydrate called cellulose provides rigid structure that protects and supports cell Lysosome Garbage can -animals only. Uses enzymes to digest waste products

Endoplasmic Reticulum-Network of membranes that fold, modify, and transports proteins throughout the cell Golgi Apparatus-receives proteins and lipids (fats); modifies, sorts, and packs them; works closely with the ER

Cells all begin as undifferentiated Undifferentiated=not different; the same DNA determines the type of cell (ex. nerve cell, muscle, blood ) We will talk more about this later!

Mitochondria? Why? Chloroplasts? Why? Cell organelles can be more concentrated based on needs!

Candy Cells

Identify the following cell membranes by function: 1. Control center of the cell 2. Protective barrier for all cells 3. Storage organelle 4. Digestive organelle 5. Organelle responsible for making ATP

Decide whether the cell is plant or animal. Next, label the parts with the appropriate name.

Structure and Adaptations

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

Unicellular organisms have many structures that help them survive Contractile vacuoles Cilia Flagella Pseudopods Eyespots

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=pahut0r CKYc

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

https://www.youtube.com/watch?v=qgam6h MysTA 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

https://www.youtube.com/watch?v=psypngb G394 Pseudopods False feet that help the unicellular organism move about Sometimes used to obtain food (phagocytosis)

Recall that taxis is an innate behavior in response to an outside stimuli

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

https://www.youtube.com/watch?v=2koagkg miqg 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

Explain how a protest extends a pseudopod. How are cilia and flagella similar? How are they different? Provide an example of a situation in which an organism would exhibit negative phototaxis.

Identify the following cells: