Honors Biology
Chapter 7 Section 2
Eukaryotic Cell Structure
SC B -2.2: SUMMARIZE THE
STRUCTURES & FUNCTIONS OF
ORGANELLES FOUND IN A EUKARYOTIC
CELL(INCLUDING THE NUCLEUS,
MITOCHONDRIA, CHLOROPLASTS,
LYSOSOMES, VACUOLES, RIBOSOMES,
ENDOPLASMIC RETICULUM [ER], GOLGI
APPARATUS, CILIA, FLAGELLA, CELL
MEMBRANE, NUCLEAR MEMBRANE, AND
CYTOPLASM
Cytoplasm
 Portion of the cell including everything inside
cell membrane except nucleus
 Cytosol: liquid portion of cytoplasm
NUCLEUS
 Contains DNA with its coded instructions for
making proteins so is the “control center”
 most prominent structure seen with light
microscope
 Parts:
 Nucleolus
 Nuclear Envelope
 Nuclear Pores
NUCLEUS
 Nucleolus


dense region in nucleus
produces subunits of ribosomes
 Nuclear Envelope


dbl membrane surrounding
nucleus
Outer layer contiguous with ER
 Nuclear Pores


holes thru envelope
substances enter/leave nucleus
thru these pores
DNA in NUCLEUS
 chromatin: DNA bound to proteins (called
histones)
 Chromatin condenses into chromosomes
when cell starts cell division
RIBOSOMES
 assembly site for proteins
 2 subunits
Small
 Large
 made separately in nucleolus  exit nucleus thru
nuclear pores  join when making proteins

RIBOSOMES
 Considering the function of ribosomes…. What types
of cells do you think would have an abundance of
ribosomes in them?
Endoplasmic Reticulum (ER)
 Internal membrane system
 2 types:
1. Smooth ER (SER)
2. Rough ER (RER)
SER
 make membranes for
cell membrane
 other organs

 detoxifies
drugs
 alcohol
 poisons

SER
 So… considering the functions of
SER……what types of cells can you predict
might have an abundance of SER?
RER
 “rough” because outer membrane is studded
with ribosomes
 proteins made & released into RER where
they are modified (sugar groups added
making a glycoprotein)
 most of proteins made here are destined for
export out of cell
RER
 What type of cell do you think would have lots of
RER?
GOLGI APPARATUS
 stack of curved membranes
 usually found between ER and cell
membrane
 Function: modify, sort, & package material
received from ER  storage in cell or export
out of cell
GOLGI
GOLGI
 In what types of cells do you think there
would be an abundance of Golgi bodies?
LYSOSOMES
 membrane bound vesicle that has enzymes
inside
 Function: breakdown of macromolecules into
smaller molecules which are then recycled in
cytoplasm

Where do these macromolecules come from?
Lysosomes
 Where do lysosomes get the macromolecules?
 worn
out organelles
 engulfed bacteria or cell debris
VACUOLES
 membrane bounded storage facility
 Protists (one-celled organisms) put food
particles in a food vacuole until need the
nutrients
 plant cells have distinctive large central
vacuole that stores water and some nutrients
and helps plant maintain turgor when all
cells have a filled central vacuole
Vacuoles
Food Vacuole
MITOCHONDRIA
 convert chemical energy in sugars ATP
(high energy molecule that temporarily
stores energy in form cells can use) =
cellular respiration
 dbl membrane
 intermembrane space
 cristae : folds of inner membrane
 matrix: inside folds of cristae
 has own DNA (maternal) & divides on own
Mitochondria
Mitochondria
CHLOROPLASTS
 in plant cells
 capture energy in sunlight chemical energy
(photosynthesis)
 dbl membrane
 intermembrane space
 inner membrane folds into thylakoid discs
 stack of discs = granum
 space around grana = stroma
 contain chlorophyll
 + DNA & divides on own
Chloroplasts
Chloroplasts
Chloroplasts
CYTOSKELETON
 Function:
internal structure & support
 movement of organelles & chromosomes
 anchors organelles and cells
Made of proteins

3 types:
1. microfilaments
2. intermediate filaments
3. microtubules
MICROFILAMENTS
 made of actin
 supports cell shape
 used by protist for movement

http://highered.mcgrawhill.com/sites/9834092339/student_view0/chapter
4/animation_-_cytoplasmic_streaming.html
Microfilaments
Intermediate Filaments
 used to move organelles around cytoplasm
MICROTUBULES
 largest, strongest
 shaped like hollow straws with units that
spontaneously come together or fall apart
 used to move organelles, chromosomes
 made in centrosomes
CELL ANALOGY
 Eukaryotic cells are like a city:
 each part has a job to be done
 Nucleus : mayor
 Mitochondria: power plant
 Lysosomes: city dump and recycling center
 SER: hospital
 Golgi: UPS store
 Cytoskeleton: roads & bridges
 Cell Membrane: border patrol @ city limits