Eukaryotic Cell Structures

1
All About Cells

• Eukaryotic Cell Structures

2
The Basics of a Cell

• Much like our bodies are made up of organs, cells
  are made up of smaller parts called organelles.
• Eukaryotic cells are divided into two major
  parts
• The nucleus
• The cytoplasm the portion of the cell outside
  the nucleus

3
The Nucleus

• The nucleus
• Is the control center of the cell
• Contains almost all of the cells DNA
• The nucleus contains codes that allows it to make
  proteins and other important molecules

4
The Parts of the Nucleus

• The parts of the nucleus
• Nuclear envelope the two membrane structure
  that surrounds the nucleus
• Nuclear pores pores on the surface of the
  nuclear envelope that allow material to move in
  and out of the nucleus
• Chromatin consists of DNA bound to protein, and
  is spread throughout the nucleus when the cell
  divides the chromatin condenses to form
  Chromosomes.
• Chromosomes contain the genetic material that
  is passed from one generation to the next.
• Nucleolus where the assembly of ribosomes
  begins

5
Ribosomes

• Ribosomes are small particles of RNA and protein
  found throughout the cytoplasm
• They produce proteins by following the
  instructions of the nucleus
• Can be found
• Attached to membranes of cell organelles
• Free floating

6
Endoplasmic Reticulum

• The site of where lipid components of the cell
  membrane are assembled, along with proteins and
  other materials that are exported from the cell

7
Types of Endoplasmic Reticulum

• There are two types of Endoplasmic Reticulum, or
  ER
• Rough ER which is involved in the synthesis of
  proteins
• Called rough ER because of the ribosomes found on
  its surface
• Smooth ER in many cells, contains enzymes that
  perform specialized tasks, including the
  synthesis of membrane lipids and the
  detoxification of drugs
• Called smooth ER because of the lack of ribosomes
  found on its surface

8
Golgi Apparatus

• Proteins produced in the Rough ER move into the
  Golgi Apparatus
• The function of the Golgi Apparatus is to modify,
  sort, and package proteins and other materials
  from the ER for storage in the cell or secretion
  outside the cell

9
Lysosomes

• Filled with enzymes
• One function is the digestion, or breakdown, of
• Lipids
• Carbohydrates
• Proteins
• This allows the rest of the cell to use this fuel
• They also function to breakdown other organelles
  that have reached the end of their usefulness

10
Vacuoles

• Storage in the cell
• Store materials such as
• Water
• Salts
• Proteins
• Carbohydrates
• In many plants, there is a single fluid filled
  vacuole
• This feature in plants make is possible for them
  to support heavy structure such as leaves and
  flowers
• Also can be found in some animals and unicellular
  organisms

11
Mitochondria

• Organelles that convert the chemical energy
  stores in food into compounds that are move
  convenient for the cell to use
• Considered the power house of the cell
• Enclosed by two membranes the inner membrane is
  folded up
• Your mitochondria is inherited from your mother!

12
Chloroplasts

• Organelles that capture energy from sunlight and
  convert it into chemical energy in a process
  called photosynthesis
• The biological equivalent to a solar power plant
• Surrounded by two membranes
• Inside the organelle are stacks of other
  membranes with contain the green pigment
  chlorophyll

13
Cytoskeleton

• Supporting structure and transportation system in
  the cell
• A network of protein filaments that helps the
  cell to maintain its shape
• Also involved in movement
• Two principle proteins filaments make up the
  cytoskeleton
• Microfilaments
• Microtubules

14
Microfilaments

• Threadlike structures made of a protein called
  ACTIN
• Form an extensive network in some cells and
  produce a tough, flexible framework that supports
  the cell
• Also can help the cell move

15
Microfilaments

• In animal cells, structures known as centrioles
  are formed from tubulin
• Centrioles
• Are located near the nucleus
• Help aid in cellular division

16
Microfilaments

• Microtubules also help to build projections from
  the cell surface that enable cells to swim
  rapidly through liquids
• These projections are
• Cilia/Cilium
• Flagella/Flagellum

17
Microtubules

• Hollow structures made up of proteins known as
  TUBULINS
• Play critical roles in maintaining cell shape
• Also important in cell division they help
  separate the chromosomes

18
Analogies

• A comparison between two different things in
  order to highlight some point of similarity
• For example science writer Claudia Kalb relies
  on the computer to explain how our brains process
  memories
• Some basic facts about memory are clear. Your
  short-term memory is like the RAM on a computer
  it records the information in front of you right
  now. Some of what you experience seems to
  evaporate--like words that go missing when you
  turn off your computer without hitting SAVE. But
  other short-term memories go through a molecular
  process called consolidation they're downloaded
  onto the hard drive. These long-term memories,
  filled with past loves and losses and fears, stay
  dormant until you call them up.("To Pluck a
  Rooted Sorrow," Newsweek, April 27, 2009)

19
The Cell As A Factory

• Membrane the walls, floor and roof of the
  factory
• Cytoplasm the air in the factory
• Nucleus the main office in a factory
• Ribosomes small machines, turning out proteins
  on the orders of its boss the nucleus

20
The Cell As A Factory

• Endoplasmic Reticulum
• Rough ER - Assembly line, gets proteins from the
  ribosomes and modifies them
• Smooth ER Specially trained workers
• Golgi Apparatus Customization shop, putting the
  finishing touches on proteins and readying them
  for shipment, then ships the proteins to the
  parts of the cell where they are needed
• Lysosomes the cleanup crew of the factory

21
The Cell As A Factory

• Vacuoles the storage room
• Mitochondria the powerhouse of the factory,
  converting one form of energy into another
• Chloroplasts solar power plants, providing
  energy to the factory
• Cytoskeleton the steel or cement beams and
  columns that provide the factorys structure