Cell Structure Part 2: Eukaryotic Cells (Animal Cells vs. Plant Cells)

Honors Biology

Eukaryotic Cells

• Divided into compartments• Unicellular or Multicellular • Organelles → structures that have a specific

function in the cell (including the nucleus)• Cytoplasm → region between nucleus and

plasma membrane that surrounds organelles– Filled with cytosol (watery-jelly part) and organelles– Contains centrioles, which help with cell division

reproduction

2

Types of Eukaryotic Cells

1)Animals2)Plants3) Fungi4) Protists

Types of Eukaryotes• Unicellular (Protozoa)

– Protists• Paramecium, amoebae

– Fungi• Yeast

• Multicellular (Metazoa)– Fungi– Plants– Animals

• Reproduction for ALL eukaryotes may be asexual or sexual

ORGANELLES• Very small• Perform various functions for cell• Found in the cytoplasm• May or may not be membrane-

bound

BASIC ANIMAL CELL ORGANELLES

Nucleolus

Nucleus

Nuclear envelope

Ribosome (attached)Ribosome (free)

Cell Membrane

Rough endoplasmic reticulum

Golgi apparatus

Mitochondrion

Smooth endoplasmicreticulum

Centrioles

BASIC PLANT CELL ORGANELLES

Organelle ListAnimal Cell Both Plant Cell

•Smaller vacuoles •Centrioles •Flagella and cilia•Lysosomes

•Nucleus• Nucleolus• Ribosome• Smooth ER• Rough ER• Golgi apparatus• Mitochondria• Cell Membrane• Cytoplasm • Cytoskeleton•Vesicle•Centrosome

•Cell wall•Large central vacuole•Chloroplasts

CELL OR PLASMA MEMBRANESTRUCTURE• Made of double layer (bilayer) of:

phospholipids and proteins• Surrounds outside of ALL cellsFUNCTION (JOB)• Controls what enters or leaves the cell• Security guard or a fenceFOUND:• ALL CELLS

Outsideof cell

Insideof cell(cytoplasm)

Cellmembrane

Proteins

Proteinchannel

Lipid bilayer

Carbohydratechains

CYTOPLASM OF A CELL

STRUCTURE• Jelly-like substance• Mostly water

• aqueous solutionFUNCTION (JOB)• Provides a solution for

chemical reactions to take place in

• Holds organelles in place • *OceanFOUND:• ALL CELLS

cytoplasm

NUCLEUSSTRUCTURE• Contains the DNA (genetic

information) in chromosomes• Bounded by a

nuclear envelope (membrane) with pores

• Usually the largest organelleFUNCTION (JOB)• Controls the normal

activities of the cell

• Main OfficeFOUND:•All eukaryotic cells

12

NUCLEAR ENVELOPE• Double membrane

surrounding nucleus• Also called nuclear membrane• Contains nuclear pores for

materials to enter & leave nucleus

• Connected to the rough ER

Nuclear pores

13

INSIDE THE NUCLEUS The genetic material (DNA) is found

DNA is spread out And appears as CHROMATINin non-dividing cells(NOT TIGHTLY COILED)

DNA is condensed & wrapped around proteins forming as CHROMOSOMES in dividing cells(TIGHTLY COILED)

NUCLEOLUSSTRUCTURE• Inside nucleus• Cell may have 1 to 3 nucleoli• Disappears when cell dividesFUNCTION (JOB)• Makes ribosomes (ribosomal

subunits)Found:• All Eukaryotic Cells

14

Endoplasmic Reticulum (ER)

• Folded membranes• Moves supplies from one part of the cell to another

– This helps maintain homeostasis

• Detoxifies the cell• Two types of ER…

15

ROUGH ENDOPLASMIC RETICULUM (RER)

STRUCTURE• Has ribosomes on its

surfaceFUNCTION (JOB)

– Makes more membrane– Modifies and helps make

proteins that are being transported out

FOUND:• Plant and animal cells

SMOOTH ENDOPLASMIC RETICULUM (SER)

STRUCTURE• Has NO ribosomes on its

surface• Usually attached to RERFUNCTION (JOB)• Makes lipids (membranes)• Regulates calcium

(muscles)• Destroys toxins (Liver)FOUND:Plant and animal cells 17

Golgi Apparatus• Receives vesicles (of protein) from the ER• Processes, sorts, and ships proteins • NOT interconnected• One side = receives vesicles• One side = ships to plasma membrane or become

lysosomes• Looks like a flattened stack of pancakes

18

UPS/Fedex warehouse packing center

GOLGI APPARATUS (BODIES)STRUCTURE

Stacks of flat sacsLooks like pancakes with

syrup drips“Pankcakes” NOT

connectedFUNCTION (JOB)• Modify• Sort• Package • molecules from ER for

storage OR transport in transport vesicles

FOUND:• Plant and animal cells

Transport vesicle

“syrup bubble”

Lysosomes

• Digestive/recycling center of the cell• Sac of digestive enzymes• Produced by the Rough ER

and Golgi• Breaks down “bad” organelles

20

Like a garbage disposal!

LYSOSOMESSTRUCTURE• They have a low pH • Contain digestive enzymes

FUNCTION (JOB)• Break down food, bacteria & old

cell parts• Lyse & release enzymes to break

down/recycle cell parts• Programmed for cell death

(APOPTOSIS)• Think= “Lysol” cleanerFound:Animal cells only

(a) Phagocytosis: lysosome digesting food

1 µm

Lysosome containsactive hydrolyticenzymes

Food vacuole fuses with lysosome

Hydrolyticenzymes digestfood particles

Digestion

Food vacuole

Plasma membraneLysosome

Digestiveenzymes

Lysosome

Nucleus

CYTOSKELETONSTRUCTURE• Made of proteins• Microfilaments-threadlike• Intermediate Filaments • Microtubules-tubelike

FUNCTION (JOB)• Network of fibers that help cell

maintain cell shape• Also help move organelles around• Structural support for animal cellsFOUND:• ALL CELLS

CILIA & FLAGELLAFUNCTION (JOB) of Flagella• Moves WHOLE cells

FUNCTION (JOB) of Cilia• Moves fluids or small particles across cell

surface

FOUND:• Animal cells and some plants• Flagella (prokaryotes)

CILIA & FLAGELLASTRUCTURE• Made of protein

tubes called microtubules

Cilia –Shorter –more numerousFlagella – Longer – fewer (usually 1-3)

Vacuoles• Storage “containers”

– Store various substances– The “closet” of the cell

STRUCTURE AND FOUND:• In animals = small and numerous• In plants = one large central vacuoleFUNCTION:

– Stores mostly water but also waste and nutrients– Helps with the structure of a plant cell

25

Energy Organelles

• Two “energy” organelles– Chloroplasts– Mitochondria

• Both contain their own DNA

26

Energy Organelles• Chloroplast

– Site of Photosynthesis– Converts energy from the sun into chemical energy– Only in Plants and some Protists

• Mitochondria– Site of Cellular Respiration makes ATP

• ATP required for cell activity!!!!– ENERGY!! Powerhouse of the cell– Found in almost all eukaryotic cells– Two membranes inner membrane is folded up to

increase the surface area27

STRUCTURE• Bean shape• DOUBLE membrane• Has its own DNA• Folded inner membrane

called CRISTAE (increases surface areafor more chemical reactions)

• Interior called MATRIX

MITOCHONDRION(PLURAL = MITOCHONDRIA)

29

FUNCTION (JOB)• “Powerhouse” of cell• Makes cellular energy (ATP)• More active cells like muscle

cells have MORE mitochondria• Site of CELLULAR

RESPIRATION (burning glucose)

MITOCHONDRION (CON’T)

INTERESTING FACT ---• Mitochondria

Come from cytoplasm in the EGG cell during fertilization

Therefore …• You inherit your

mitochondria from your mother!

CHLOROPLASTSSTRUCTURE• Bean shape• DOUBLE membrane• Sacs (“coins”) called Thylakoids• Thylakoids stack called Granum

(pl. =grana)• Stroma – gel in middle• Has its own DNA

FUNCTION (JOB)• Found only in autotrophs• Carries out photosynthesis

FOUND:• PLANT CELLS

CELL WALLSTRUCTUREFound in:• plants

• Made of cellulose• Fungi

• Made of chitin• Bacteria

• Made of peptidoglycan

FUNCTION (JOB)• Protect• Maintain shape

Cell wall

Cell Structures – Plant Cells ONLY• Cell Wall

– Rigid, tough– Made of cellulose

• Large Central Vacuole– Fills with water and increases turgor pressure (pressure in a cell)

• Chloroplasts

33

RIBOSOMESSTRUCTURE• Made of PROTEINS and rRNAFUNCTION (JOB)• Make proteins– amino acids to make proteins• Process called TRANSLATIONFOUND:ALL CELLS

RIBOSOMES (CON’T)Can be attached to

Rough ER (proteins made exit cell)

OR

Be free (unattached) in the cytoplasm

(proteins made stay INSIDE cell)

CENTRIOLESSTRUCTURE• Found only in animal

cells• Paired structures near

nucleus (“t” shape”)• Made of microtubulesFUNCTION (JOB)• Appear during cell

division• Help to pull chromosome

pairs apart to opposite ends of the cell

CENTRIOLES & THE MITOTIC SPINDLE

**Made of MICROTUBULES (Tubulin)

NOW…LET’S PRACTICE

Animals vs. Plants

39

• Cell wall• Large central

vacuole• Chloroplasts

• Smaller vacuoles • Centrioles • Flagella and cilia• Lysosomes

• Nucleus• Nucleolus• Ribosome• Smooth ER• Rough ER• Golgi• Mitochondria• Cell Membrane• Cytoplasm • Cytoskeleton•Vesicle•Centrosome