Cells

Early Microscopes-Lenses and microscopes:

- 1600s – Holland: lenses combined to form

microscopes and telescopes

- Late 1500s – Italy: merchants develop magnifying

lenses to examine the quality of cloth

Early Microscopes-It was not until the mid-1600s that scientists began to

use microscopes to observe living things

- Under the microscope, cork seemed to be made of

thousands of tiny, empty chambers

-1665 – Robert Hooke (England) built compound

microscope

- looked at thin sections of cork

Early Microscopes- Hooke called

these chambers

“cells” because

they reminded

him of a

monastery's tiny

rooms, which

were called cells

Early Microscopes- 1674 – Anton van Leeuwenhoek used a single-lens

microscope to observe pond water

- The microscope revealed a

fantastic world of tiny living

organisms that seemed to be

everywhere

- He used a single-lens microscope

Early Microscopes- 1838 – Matthias Schleiden concluded that all plants are

made of cells

- 1855 – Rudolf Virchow observed onion root tip cells

and concluded that new cells could only be produced by

division of existing cells

- 1839 – Theodor Schwann stated that all animals made

of cells

The Cell Theory- It became clear that cells

are the basic unit of life

- The cell theory grew out of

the work of many scientists

and improvements in the

microscope.

The Cell Theory- The Cell Theory has

three principles:

- All living things

are made of cells

The Cell Theory- The Cell Theory has three principles:

- All living things are made of cells

- Cells are the basic units of structure and function in living things

The Cell Theory- The Cell Theory has three principles:

- All living things are made of cells

- Cells are the basic units of structure and function in living things

- New cells are produced from pre-existing cells

Prokaryotes vs Eukaryotes - Cells come in a great variety of shapes and an amazing

range of sizes

- They are surrounded by a barrier called a cell

membrane

- All cells have two characteristics in common

- They contain the molecule that carries biological

information—DNA

Prokaryotes vs Eukaryotes - Cells fall into two broad categories, depending on

whether they contain a nucleus

- Nucleus:

- A large structure with its own membrane that holds

the cell’s genetic material (DNA)

- The nucleus controls many of the cell's activities

Prokaryotes vs Eukaryotes - Prokaryotes:

- Cells that do NOT contain nuclei

- The organisms we call bacteria are prokaryotes

- Generally smaller and simpler - Do not have membrane-bound organelles

- Have genetic material that is not contained in a nucleus

Prokaryotes vs Eukaryotes - Eukaryotes:

- Cells that do contain nuclei

- Display great variety

- Lives as single-celled organisms

- Large, multicellular organisms

- Generally larger and more complex

- Dozens of structures and internal membranes, and many are highly specialized

- Contain a nucleus in which their genetic material is separated from the rest of the cell

- Plants, animals, fungi, and protists

Prokaryotes vs Eukaryotes - Similarities between Prokaryotes & Eukaryotes:

- Come in a variety of shapes and sizes

- Both have DNA

- All cells are enclosed by a membrane

- All cells are filled with cytoplasm

- Cells tend to be microscopic

Exploring the Cell- Researchers use microscopes and techniques more

powerful than the pioneers of biology could have

imagined

- Researchers can use fluorescent labels and light

microscopy to follow molecules moving through the cell

- Confocal light microscopy, which scans cells with a

laser beam, makes it possible to build three-dimensional

images of cells and their parts

Images produced by light microscope

Exploring the Cell- Electron microscopes are capable

of revealing details as much as

1000 times smaller than those

visible in light microscopes

- Transmission electron microscopes

(TEMs) make it possible to explore

cell structures and large protein

molecules

Exploring the Cell- With scanning electron

microscopes (SEMs), a pencillike

beam of electrons is scanned over

the surface of a specimen

- The scanning electron microscope

produces stunning

three-dimensional images of cells

Nerve broken open, revealing vesicles containing neurotransmitters

Used toothbrush covered in plague

Typical virus

Prokaryotic vs Eukaryotic Reading, Video, & Double Bubble Thinking Map

Prokaryotic Reading & Coloring Activity

Parts of a Microscope & Microscope Lab

Animal Cell & Plant Cell Doodle Notes

Animal & Plant Cell Organelle Notes along with Flip Picture Book

Cell Boundaries - All cells are surrounded by a thin, flexible barrier

known as the cell membrane

- Cell Membrane:

thin, flexible

barrier around a cell;

regulates what enters

and leaves the cell

Cell Boundaries

- Let’s Review!

- Cell Membranes are made up of LIPIDS

- The cell membrane

regulates what

enters and leaves the

cell and also provides

protection and

support

Cell Boundaries - What two

monomers make up a

LIPID?

- Glycerol- Fatty Acid

Cell Boundaries - Draw individual Lipids & Label

their structures

- Glycerol (Head)

Hydrophilic : Likes Water

- Fatty Acid (Tails)

Hydrophobic: Hates Water

Cell Membrane - The composition of nearly all cell membranes is a

double-layered sheet called a lipid bilayer

- Lipid Bilayer:

- double-layered sheet that forms the core of nearly

all cell membranes

- hydrophilic heads point out, hydrophobic tails point

inside

Draw & Label the Lipid BilayerExtracellular (Outside the cell)

Intracellular (Inside the cell)

Hydrophilic “Heads”→

Hydrophobic “Tails”→

Cell Membrane

- Carbohydrate molecules are attached to many of these

proteins

- Some of the proteins form channels and pumps that

help to move material across the cell membrane

- In addition to lipids, most cell membranes contain

protein molecules that are embedded in the lipid bilayer

- Many of the carbohydrates act like chemical

identification cards, allowing individual cells to identify

one another

Color & Label Cell Membrane

Cell Walls

- Cell walls are present in many organisms, including

plants, algae, fungi, and many prokaryotes

- The main function of the cell wall is to provide support

and protection for the cell

- Many cells also produce a strong supporting layer

around the membrane known as a cell wall

Cell Walls

- Most cell walls

are made from

fibers of

carbohydrate and

protein

- Cell walls lie outside the cell membrane

- Most cell walls are porous enough to allow water,

oxygen, carbon dioxide, and certain other substances to

pass through easily

Cell Walls

- Cellulose is the

principal component

of both wood and

paper

- Plant cell walls are

composed mostly of

cellulose, a tough

carbohydrate fiber

Cell Wall

Cell Membrane Doodle Notes

Cell Transportation

- One of the most important functions of the cell

membrane is to regulate the movement of dissolved

molecules from the liquid on one side of the membrane

to the liquid on the other side

- Every living cell exists in a liquid environment that it

needs to survive

Cell Transportation

- Concentration:

The mass of solute in a given volume of solution, or

mass/volume

- The cytoplasm of a cell contains a solution of many

different substances in water

Cell Transportation

Concentration is 12 grams /3 Liters (g/L)

THINK MATH: 12 / 3 is ?

- Example:

12 grams of salt in 3 liters of water

THEREFORE IT IS: 4 g/L

Cell Transportation

Concentration is 12 grams /6 Liters (g/L)

- Practice:

12 grams of salt in 6 liters of water

Final Concentration is : 2 g/L

Cell Transportation- Which solution is more concentrated?

4 g/L 2 g/L

Cell Transportation

- Diffusion:

process by which molecules tend to move from an

area where they are more concentrated to an area

where they are less concentrated

- In a solution, particles move constantly

- Molecules naturally move from HIGH concentration to

LOW concentration

Cell Transportation

- Equilibrium:

when the concentration of a solute is the same

throughout a solution

- The substances will be evenly spaced out

- Because diffusion depends upon random particle

movements, substances diffuse across membranes

without requiring the cell to use energy

- The solution will eventually reach equilibrium

Cell Transportation - Even when equilibrium is reached, particles of a

solution will continue to move across the membrane in

both directions

- Selectively Permeable:

Some substances can pass through the cell membrane

while other substances cannot

Also referred to as semipermeable membranes

- Most biological membranes are selectively permeable

Diffusion Station for Notes

Cell Transportation - Endocytosis:

- process of taking material into the cell by means of

infoldings, or pockets, of the cell membrane

- Two types:

Phagocytosis & Pinocytosis

- Larger molecules and even solid clumps of material

may be transported in through this process

Cell Transportation - Phagocytosis:

- process in which

extensions of cytoplasm

surround and engulf large

particles and take them into

the cell

- It means “cell eating”

Cell Transportation

- Engulfing material in this

way requires a considerable

amount of energy

- Due to this, it is correctly

considered a form of active

transport

Cell Transportation - Pinocytosis:

- process by which a cell

takes in liquid from the

surrounding environment

- Tiny pockets form along the

cell membrane, fill with liquid,

and pinch off to form vacuoles

within the cell

Cell Transportation - Exocytosis:

- process by which a cell

releases large amounts of

material outside the cell

- The membrane of the vacuole

surrounding the material fuses

with the cell membrane, forcing

the contents out of the cell

Diffusion Lab