Eukaryotic CellsThe Inside Story

Prokaryotic Cells

• No nucleus• No

membrane-covered organelles

• Circular DNA

• Bacteria

Eukaryotic Cells

• Nucleus• Membrane -

covered organelles

• Linear DNA• All other

cells

DNACells

2 Types of Cells

Which is which?

1 of the 3 parts of the Cell Theory states that All cells come from pre-existing cells

So just as large multicellular organisms like humans, dogs, and trees reproduce, your cells do as well

Cells come from..

It turns out that there is a lot more inside a cell than Robert Hooke or Anton von Leeuwenhoek probably would have guessed.

Everything, from the structures covering the cells to the structures inside, perform tasks to help keep the cells alive.

These structures are called organelles.

So What is Inside a Cell?

All cells have outer coverings that separate what’s inside the cell from what is outside.

Cell Membrane Covers all cells, both eukaryotic and

prokaryotic Duties include keeping cytoplasm inside Allow nutrients in and waste products out Also interacts with things outside the cell

Holding It All Together

Cell Wall Only found in plant and bacteria(prokaryotic)

cells

Cell wall in plants is made of cellulose

Provides strength and support to the cell membrane

The strength of billions of cell walls in plants enables a tree to stand tall and its limbs to defy gravity

Holding It All Together

Nucleus Largest and most visible organelle Covered by a membrane Control center of cell Stores the DNA

Nucleolus Dark spot inside the nucleus Stores the materials that will be used later to

make ribosomes in the cytoplasm

The Cell’s Library

Ribosomes Smallest but most abundant organelles

Their job is to hook together amino acids to make proteins

Found in both eukaryotic and prokaryotic cells

Not covered by a membrane

All cells have ribosomes because all cells need protein to live.

Protein Factories

Endoplasmic Reticulum Internal delivery system of a cell Is divided into Smooth and Rough ER based

on appearance and function Rough ER

Ribosomes are attached making it look pebbled

Specializes in protein synthesis Connected to nuclear membrane Proteins synthesized by ribosomes collect in

the ER for transport throughout the cell

The Cell’s Delivery System

Smooth ER Does not have ribosomes attached

Has different functions depending on the cell type

Can be responsible for lipid and hormone synthesis

Breaks down drugs and certain other chemicals that could damage the cell

Difference Between Rough and Smooth ER

Mitochondria Convert the chemical energy stored in food into

ATP which is the molecular fuel that cells use to do work

Inner membrane of mitochondria that has many folds is where most of the ATP is made.

The reason you breathe air is so that mitochondria have the oxygen they need to make ATP

Highly active cells, like those in the liver and heart, may have thousands of mitochondria while other cells may have only a few.

The Cell’s Power Plants

Chloroplasts Additional kind of energy-converting

organelle found in plants and algae Contain flattened, membrane-covered

sacs that look like stacks of coins which contain chlorophyll

Chlorophyll is what makes plants green and also traps the energy in sunlight which plants use to make sugar

The sugar that is produced is used by mitochondria to make ATP

The Cell’s Power Plants

Golgi Apparatus Looks like ER but is located closer to the

cell membrane Receives and modifies lipids and proteins

sent from the ER Final products are then enclosed in a piece

of the Golgi’s membrane that pinches off to form small compartment

Compartment transports contents to other parts of cell or outside the cell

The Cell’s Packaging Center

Vacuoles Very large in plant cells, much smaller in

animal cells Store water and other liquids If full of water they help support the cell

Store the liquids that make roses red and violets blue

Contain the juices you associate with oranges and other fruits

The Cell’s Storage Centers

Vesicles Some form when part of the membrane

pinches off the ER or Golgi

Others are formed when part of the cell membrane surrounds an object outside the cell

The Cell’s Storage Centers

Lysosomes Special vesicles in animal cells that

contain enzymes that digest food particles and wastes

Destroy worn-out or damaged organelles Get rid of waste materials and protect

cell from foreign invaders If lysosome membrane breaks, the

enzymes spill out into the cytoplasm which kills the cell

Packages of Destruction

Plant or Animal?

Plant or Animal?

You are going to create a drawing of a eukaryotic cell.

However, instead of making it a realistic cell, your cell should be made of drawings of objects that represent the organelle’s job.

For example, the Golgi Apparatus, which transports materials, could be a bus or a car.

Homework