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

Cell Wall

Think about it: What is the plant cell made of? (Hint: What substance do plants make during photosynthesis?)

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=pahUt0RCKYc

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

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=QGAm6hMysTA

Pseudopods

“False feet” that help the unicellular organism move about

Sometimes used to obtain food (phagocytosis)

https://www.youtube.com/watch?v=PsYpngBG394

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 single-cell or multicellular organisms

Find food (e.g., glucose)

Flee from poisons (e.g., phenol)

Critical to early development

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

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

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: