CELL STRUCTURE AND FUNCTION

Karyotic- from Greek karyon meaning nut or kernel (referring to the nucleus here)

Prokaryotic vs. Eukaryotic Cells

Pro- Latin meaning for

before

Eu- Greek meaning for

true

Prokaryote or Prokaryotic means “before nucleus”

Prokaryotic vs. Eukaryotic Cells

Eukaryote or Eukaryotic means “true nucleus”

Prokaryotic Cells are also known as bacteria!

Prokaryotic Cells

■ Have No Nucleus.

■ Lack Internal Membranes (meaning no internal structures with membranes-like organelles).

■ Genetic Material is a single circular DNA molecule floating in the cytoplasm.

■ Always single celled & microscopic.

Prokaryotic Cells (Bacteria)

■Contain the following cell structures:

■Cell Wall

■Cell Membrane

■DNA

■Ribosomes

■Cytoplasm

Prokaryotic Cells (Bacteria)

Prokaryotic cells are much smaller and less complex than Eukaryotic cells.

Prokaryotic Cells (Bacteria)

They can reproduce

much quicker than

Eukaryotic cells

however.

Beneficial Bacteria

Not all bacteria are bad. Very few actually

cause disease.

Bacteria in and on us help:

■ Provide nutrients: break down food, make vitamins.

■ Keep away harmful microbes by filling spaces that

would be filled by disease-causing bacteria.

■ Help chemically break down dairy products to make

yogurt and cheese, turn cucumbers to pickles, or to

make soy sauce and vinegar.

Beneficial Bacteria

In Ecosystems:

■ Produce oxygen, recycle

carbon, nitrogen, hydrogen

and sulfur.

■ Helps make minerals in the

soil for plant growth.

■ Bioremediation: break down

pollutants (ex. Oil)

■ Recycling and composting:

biodegradable often means it

can be broken down by

bacteria.

Include all cells that have a nucleus.

Eukaryotic Cells

■ Have a Nucleus

■ Have Membrane Bound Organelles (tiny “organs”)

■ Genetic material in the form of linear (straight) chromosomes

■ Includes both single celled and multi celled varieties. Almost all are still microscopic.

Eukaryotic Cells

A Generalized Eukaryotic Cell Diagram

•although cells come in many shapes and

sizes…

Human cell size and shape comparison:

Types of Eukaryotic Cells:

■Animal Cells

■Plant Cells

•Both types have many of

the same internal parts but

there are also a few parts

unique to either just plants

or just animals.

•Let’s start with the parts

common to both types…

Cell Parts Plants & Animals

Have in Common:

Cell Membrane

Nucleus

Ribosomes

Cytoplasm

Endoplasmic Reticulum

Golgi Apparatus

Vesicles

Mitochondria

Lysosomes

Cell Membrane:

■ Surrounds the cell

■ Controls movement of

materials into and out of

cell

Cytoplasm: “cyto”=something belonging to a cell.

■ Fills space

between cell

membrane and

nucleus.

■ Maintains cell

structure

■ Where many

chemical

reactions take

place.

Cytoskeleton:

Network of protein fibers

crisscrossing the cytoplasm

that constantly change to

meet the needs of the cell.

■ Give shape to the cell

■ Anchors its organelles

and serves as a “track”

for them to move on.

■ Enable cells to move

and divide.

Ribosomes:

■ Make proteins for the cell

■ Found in the cytoplasm or on the Rough Endoplasmic

Reticulum (more on this later).

■ Found in Eukaryotes and Prokaryotes

Cell Organelles: subcellular structures

• Structures specialized to perform

distinct processes.

• Each is surrounded by or made up of

membranes

• Only eukaryotes have organelles,

prokaryotes do not.

Organelles involved in making proteins

■Nucleus

■Endoplasmic

Reticulum

■Vesicles

■Golgi Apparatus

Ribosomes make

proteins, but they

need help from a

number of organelles

to do this:

Nucleus:

■ Proteins control the functions of the cell, but to create

more proteins we need to start at the nucleus.

■ Contains instructions to make proteins

■ These instructions are in the form of DNA,

■ Protects the DNA

from dangers in

the cytoplasm.

Nucleus:

Includes the following 4

structures:

■ Nuclear Envelope

(Membrane): Controls

movement into and out of

the nucleus

■ Nuclear Pore: Holes in

the nuclear envelope

which allow movement

between the nucleus and

cytoplasm.

Nucleus:

■ Nucleolus: Dense

region inside

nucleus, where

ribosomes are

assembled

■ Chromatin:

Genetic Material

(DNA) which is

organized into

structures called

chromosomes

during cell division.

Endoplasmic Reticulum

(ER): ■ Interconnected network of

channels…aids in movement of

molecules inside the cell.

■ Rough ER:

■ Ribosomes found on surface.

■ Proteins leave ribosome

and enter into ER where they

are modified.

■ Smooth ER:

■ No ribosomes on surface.

■ Make lipids (fats)

■ Break down drugs and

alcohol.

Vesicles:

■ Small membrane-enclosed sacs

■ Transport molecules from place to place

(ex. ER to Golgi Apparatus).

Golgi Apparatus:

Stack of membrane-

enclosed spaces.

Packages proteins for

distribution within the

cell and export out of

the cell.

Proteins come from

endoplasmic reticulum.

Putting it all together…

Identify each

of the

following:

A:

B:

C:

D:

E:

F:

F

E

D

C

B

A

■ Mitochondria

■ Vacuole

■ Lysosomes

■ Centrosomes

■ Cell wall

■ Chloroplasts

■ Central Water Vacuole

Other organelles:

Mitochondria:

■ Chemical reactions here provide energy for cell.

■ Converts food to usable energy for cell.

■ Have their own ribosomes and DNA.

Lysosomes:

■ Carry enzymes to

destroy cellular waste.

■ Break down

damaged/worn out cell

parts.

■ Engulf/digest targeted

molecules

■ Defend cell from

invading

bacteria/viruses

■ Membrane protects cell

from enzymes.

Lysosomes:

A cell can direct itself to die by creating a bunch of

lysosomes and breaking them open inside of itself

(apoptosis).

This can happen if a cell is infected by a virus and

also in normal development (how you lose your tail

as an embryo).

Animal Cells contain all of the previous organelles plus:

Centrioles: 2 cylindrical organelles (together

called a centrosome)■ Part of the Cytoskeleton

■ Produce microtubules that aid in

moving chromosomes during cell

division.

Plant Cells:

Cell Wall:■ Gives cells shape,

support and

protection.

■ Found in algae,

fungi and most

bacteria too.

contain all of the previous organelles (except centrioles)

as well as:

Plant Cells:

Chloroplast:■ Site of photosynthesis

where chemical reactions

create food for the cell.

■ Also found in green algae.

contain all of the previous organelles (except centrioles)

as well as:

Plant Cells:

Central Water

Vacuole:■ Single, large water filled

vacuole in the middle of

the cell.

■ Strengthen cells and

provide support for

plant.

■ Contains toxins to harm

plant predators, waste

products and pigment

for color (petals).

contain all of the previous organelles (except centrioles)

as well as:

Gerenalized Animal Cell

Generalized Plant Cell

Unicellular (one) vs.

Multicellular (many)

Unicellular: Single-Celled

■ Most common forms of

life on Earth.

■ Carry out all functions

of Life.

■ Bacteria

■ Amoeba

■ Paramecium

Unicellular (one) vs.

Multicellular (many)

Multicellular

■ Larger organisms.

■ Different cells have

specialized functions,

together making a

complete organism.■ Human

■ Rose Bush

■ Mushroom

Inner Life of the Cell

Cell Structure/Function Vocab

Prokaryotic

Eukaryotic

Cell Membrane

Nucleus

-Nucleolus

-Chromatin

Ribosomes

Endoplasmic Reticulum

-Rough vs. Smooth

Golgi Apparatus

Vesicles

Mitochondria

Lysosomes

Centriole

Cell Wall

Chloroplast

Water Vacuole

Cytoplasm

-Cytosol

-Cytoskeleton

Unicellular

Multicellular