The CellStructures and

Functions

Chapter 7 Sections

1, 2, and 3

Cell Discovery and Theory• Section 1 Main Idea:

The invention of the microscope led to the discovery of cells.

1665 Robert Hooke• Observes cork through

a microscope

• Names the tiny structures cells.

1683 Anton van Leeuwenhoek

• Discovered single-celled, animal-like organisms.

• Now we call them protozoans.

1830 to 1855

• Scientists discover the cell nucleus. 1833

• 1839 – scientists propose that both plants and animals are made of cells.

1880 to 1890

• Louis Pasteur and Robert Koch pioneer the study of bacteria.

Lynn Margulis 1970

• Proposed that organelles in Eukaryote cells were once free-living Prokaryotes cells.

Cell Theory

1. All living organisms are composed of one or more cells.

2. Cells are the basic unit of structure and organization of all living things.

3. Cells arise only from previously existing cells.

Cells pass on copies of their genetic material on to their daughter cells.

Basic Cell TypesProkaryotic Cell Eukaryotic Cell

Prokaryote Cells

Simple structure

Contains a plasma membrane

Does not contain membrane-bound organelles

Genetic material

Small

Eukaryotic Cells

More complex structure

Contains a plasma membrane

Contains membrane-bound organelles

Large

The Plasma MembraneSection 2 Main Idea:

The plasma membrane helps to maintain a cell’s homeostasis.

Thin, flexible boundary between the cell and its environment

Allows nutrients into the cell

Allows waste to leave the cell

Selective PermeabilityThe plasma membrane

controls the movement of

substances into and out

of the cell.

Controls the amount of a

substance entering the

cell.

Controls the amount of a

substance leaving the cell

The plasma membrane is

composed of the

phospholipid bilayer.

A phospholipid molecule

is composed of a glycerol

backbone, two fatty acid

chains, and a phosphate

group.

Fluid Mosaic Model

The phospholipid bilayer

allows other molecules to

“float” in the membrane.

Other Components

Proteins

Cholesterol

Carbohydrates

Proteins in the plasma membranePROTEINS:

Transmit signals inside

the cell

Act as a support

Structure

Provide pathways for

substances to enter and

leave

Cholesterol in the plasma membrane

Cholesterol

Prevents fatty acid tails from sticking together

Carbohydrates in the plasma membrane

Carbohydrates

Identify chemical signals

Which Is Which and How Do You Know?

Cell A Cell B

Structures and OrganellesSection 3 Main Idea:

Eukaryotic cells contain

organelles that allow

the specialization and

the separation of

functions within the cell.

Eukaryotic Cells contain organelles that allow the specialization and functions

within a cell.Organelles = little organs in Greek

Each organelle has a unique structure and function

The following slides will explore all the organelles that make up the structure and functions in a normal cell.

We will start with organelles that are in both plant and animal cells.

Organelles carry out essential cell process such as:

1. Protein synthesis (makes protein)

2. Energy transformation

3. Digestion of food

4. Excretion of waste

5. Cell division

CytoplasmSemi fluid material foundinside the plasma membrane.

Cytoskeleton is the fiber inthe cytoplasm that supportthe organelles in cells.

This is made up of microtubulesand microfilaments.

Nucleus is the director of all cell processes.

Most of the cell’s DNA is in the nucleus.

DNA stores the

information on how to

make proteins for cell

growth, functions and

reproduction.

Nucleus

Nuclear envelope is a

double membrane

around the nucleus.

Nuclear pores allow

substances to move in

and out of the nucleus.

NucleusChromatin is DNA that

is spread throughout the

nucleus.

The Nucleolus is the

site of ribosome

production.

Ribosome

The function of a

ribosome is to help

produce proteins.

Ribosomes are made in

the nucleolus in the

nucleus.

Endoplasmic Reticulum membrane system of folded sacs and connected channels for protein

and lipid production.

Rough ER is where ribosomes are attached.These ribosomes produceproteins to export to othercells.Smooth ER is where lipids,carbohydrates andphospholipids areproduced.

Golgi Apparatus is a flattened stack of membranes that modifies, sorts and packages proteins into

sacs called vesicles.

After proteins are made

in the Rough ER they are

sent to the Golgi

apparatus.

Proteins are packaged in

Vesicles to be sent

outside the cell’s plasma

membrane.

Mitochondria produce energy for the cell by converting fuel particles (mainly sugars) into usable

energy. The powerhouse of the cell.

The folded membranesprovide large surface areafor breaking the bonds insugar molecules.

The energy produced bybreaking bonds is stored inthe bonds of othermolecules in the cell to uselater.

Lysosomes (animal cells)Lysosomes are vesicles thatcontain digestive enzymesthat break down the worn-out organelles and food particles.

Lysosomes digest bacteriaand viruses that may enterthe cell.

Lysosomes are thecleanup crew in the cell.

Centrioles (animal cells)

Centrioles are found in

the cytoplasm of animals

near the nucleus.

Centrioles are made of

Microtubules.

Centrioles play a role in

cell division.

Vacuoles (plant cells)

Vacuoles are sacs used

to temporarily store

food, enzymes, and

other materials needed

by the cell.

Some vacuoles may

store waste produces.

ChloroplastsChloroplasts belong to a

group plant organelles

called Plastids.

Chloroplasts capture

light energy and convert

it to chemical energy in

the process called

Photosynthesis.

Cell Wall (plant cells)The cell wall is thick,

rigid fibers that surrounds

the outside of the plasma

membrane.

The cell wall protects the

cell and gives it support.

The cell wall is made of a

carbohydrate called

cellulose.

Cilia are many short projections that look like hairs.

Cilia are made of

microtubules that

extend outside the

plasma membrane.

The movement of cilia

propels cells and

organisms in their

environment.

Flagella are longer and few projections outside the plasma membrane.

Flagella move in a whip-

like motion to power a

cell or organism through

the environment.