Chapter 5: Eukaryotic Cell Structure

Question 1

Eukaryotes have a wide variety of _____ and have
evolved to live in numerous → _____

Answer 1

shapes ; habitats

Question 2

Eukaryotes are ___ than bacterial and archaeal cells

Answer 2

larger

Question 3

Eukaryotic cells have
membrane compartments in
the form of →

Answer 3

organelles

Question 4

organelles

Answer 4

These are internal cell
structures that perform
specific functions for the
cell

Question 5

Organelles allow for

Answer 5

different functions to act
independently from one
another

Question 6

The large volume of these
cells requires adequate

Answer 6

regulation, metabolic
activity, and transport

Question 7

Eukaryotic cell membrane include a phospholipid bilayer
with a high amount of →

Answer 7

sterols

• Cholesterol and ergosterol

Question 8

These sterol impact the ___ and ____of the
membrane

Answer 8

fluidity ; permeability

They can respond to low or high temperature changes
to maintain the membrane

Question 9

Eukaryotic plasma membranes contain microdomains
(lipid rafts)

Answer 9

• Areas that differ in protein and lipid composition
• Thought to help in cellular processes like signal
transduction, viral assembly and release, and →
endocytosis

Membrane also have carbohydrate chains that can form →
glycocalyx

Question 10

glycocalyx

Answer 10

carbohydrate chains

Question 11

What is the most common type of transport
system?

Answer 11

Facilitated diffusion

Question 12

Some eukaryotic microbes have

Answer 12

cell walls

Question 13

Cell walls of photosynthetic algae have

Answer 13

cellulose,
pectin, and silica

Question 14

Cell walls of fungi consist of

Answer 14

chitin and glucan

Question 15

Protists that form cysts are mode of multiple layers of

Answer 15

chitin

Question 16

Cytoplasm

Answer 16

consists of liquid cytosol and many organelles

Question 17

cytosol

Answer 17

liquid fluid in cell

Question 18

Cytoskeleton

Answer 18

vast network of interconnected filaments
within the cytoplasmic matrix

Question 19

Cytoskeleton

Answer 19

vast network of interconnected filaments
within the cytoplasmic matrix
• Filaments that form the cytoskeleton: microfilaments
(actin), microtubules, intermediate filaments, and
motor proteins
• Play a role in both cell shape and cell movement

Question 20

Actin filaments

Answer 20

small protein filaments

• Scattered within cytoplasmic matrix or organized into
networks and parallel arrays
• Composed of → actin protein
• Involved in cell motion and shape changes

Question 21

Intermediate filaments

Answer 21

diverse elements of the
cytoskeleton

• Role in cell is unclear, may play structural role
• Some shown to form→ nuclear lamina
• Others help link cells together to form →tissues

Question 22

Microtubules

Answer 22

shaped like thin cylinders and are made of
α- and β- → tubulin
• Help maintain → cell shape
• Involved with microfilaments in cell → movements
• Participate in intracellular transport processes

Question 23

Secretory Endocytic Pathway

Answer 23

• Intricate complex of membranous organelles and vesicles
that move materials into the cell from outside, from inside
to outside, and within the cell
• Endoplasmic reticulum (ER)
• Golgi apparatus
• Lysosomes

Question 24

Endoplasmic reticulum (ER)

Answer 24

membrane network of →
tubules

Functions:
• Transports proteins, lipids, and other materials within
cell
• Major site of cell membrane → synthesis

Question 25

Rough ER

Answer 25

studded with → ribosomes • Involved in protein synthesis

Question 26

Smooth ER

Answer 26

lacks ribosomes • Produces → lipids

Question 27

Golgi apparatus

Answer 27

flattened saclike network, packages materials and prepares them for → secretion

Question 28

Lysosomes

Answer 28

contain digestive enzymes that allow this organelle to perform intracellular digestion of macromolecules • Found in → animal cells • Lysosomes contain hydrolases, enzymes which hydrolyze (break down) molecules and function best under slightly acidic conditions • Maintain an acidic environment by pumping protons into their interior There are lysosome like organelles in protists and fungi, which function in storage in addition to intracellular digestion

Question 29

Secretory Pathways

Answer 29

Process that moves materials like proteins and lipids to their → proper location Transport vesicles leave the Golgi with modified and packaged proteins • Takes them either to the plasma membrane or outside of the cell "Quality assurance mechanism" • Unfolded or misfolded proteins are secreted into cytosol, targeted for destruction by ubiquitin polypeptides • Proteasomes destroy targeted proteins

Question 30

Endocytosis

Answer 30

used to bring material → into the cell • Cells take up material by enclosing them in vesicles made from the → plasma membrane • Performed by → all eukaryotes • Not found in bacteria or archaea • Pinocytosis – liquid or small particle intake • Phagocytosis – large particle intake

Question 31

Pinocytosis

Answer 31

liquid or small particle intake

Question 32

Phagocytosis

Answer 32

large particle intake involves the formation of pseudopods from the cell surface that surround and bring in a particle • Forms a phagosome

Question 33

receptor-mediated endocytosis is when endocytosis is trigger by the binding of a molecule called a ___ to a ____

Answer 33

ligand ; receptor Concentrates the ligand before it is brought into the cell

Question 34

Clathrin-dependent endocytosis

Answer 34

clathrin protein-coated pits are used to internalize hormones, growth factors, iron, and cholesterol

Question 35

Caveolin-dependent endocytosis

Answer 35

may play role in signal transduction and transport of small molecules such as folic acid as well as macromolecules

Question 36

Autophagy

Answer 36

lysosomes of eukaryotes selectively isolate and destroy bacteria, viruses, aggregated proteins, and mitochondria • Helps cell maintain homeostasis or destroy pathogens that may have entered the cell by endocytosis

Question 37

Nucleus

Answer 37

membrane bound structure that houses eukaryotic cell genetic material • Contain one or more chromosomes in the form of → chromatin

Question 38

chromosomes

Answer 38

take the form of chromatin inside the nucleus

Question 39

Chromatin

Answer 39

condensed structure of DNA and proteins wound around→ histones • Form a nucleosome “beads on a string

Question 40

Nuclear envelope

Answer 40

surrounds the nucleus • Has an inner and outer lipid bilayer and is continuous with the → ER

Question 41

Nuclear pores

Answer 41

go through the nuclear envelope allow small molecules to move between the → nucleus and the cytoplasm

Question 42

Nucleolus

Answer 42

found in the center of the nucleus • Forms ribosomes in eukaryotes • Directs synthesis and processing of → rRNA • Directs assembly of rRNA to form partial → ribosomal subunits • Ribosomes mature in → cytoplasm

Question 43

Ribosomes are larger in which cell domain?

Answer 43

Eukaryotic 80S in size: 60S + 40S subunits • Found free in the cytoplasm or bound to → RER • Still responsible for → protein synthesis

Question 44

Mitochondria

Answer 44

“powerhouse of the cell” performs metabolic processes that generates ATP when oxygen is available to the cell • Site of tricarboxylic acid cycle activity • Site where ATP is generated by electron transport and oxidative phosphorylation

Question 45

Hydrogenosomes

Answer 45

• Small energy conservation organelles in some anaerobic protists • ATP is generated by fermentation process rather than respiration • CO2 , H2 , and acetate are products

Question 46

Plastids

Answer 46

organelles of photosynthetic protists and plants • Most common type are→ chloroplasts

Question 47

chloroplasts

Answer 47

• Contain chlorophyll and use energy from sunlight to change CO2 and water to → carbohydrates and O2

Question 48

Cilia

Answer 48

short, hair-like fibers • Beat like oars through surrounding fluid, propelling organisms

Question 49

Flagella

Answer 49

long, hair-like fibers • Beat from base to end, pushing the cell along