Human Biology
Sylvia S. Mader
Michael Windelspecht
Chapter 3
Cell Structure
and Function
Lecture Outline
Part 3
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1
3.3 The Plasma Membrane and How Substances Cross It
How does tonicity change a cell?
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• Isotonic solutions
have _____ amounts
of solute inside and
outside the cell and
thus do not affect the
cell.
a. Isotonic solution
(same solute concentration as in cell)
© Dennis Kunkel/Phototake
Figure 3.9a Effects of changes in tonicity on red blood cells.
2
3.3 The Plasma Membrane and How Substances Cross It
How does tonicity change a cell?
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
• Hypotonic solutions
have _____ solute
than the inside of the
cell and lead to lysis
(bursting).
H2O
b. Hypotonic solution
(lower solute concentration than in cell)
© Dennis Kunkel/Phototake
Figure 3.9b Effects of changes in tonicity on red blood cells.
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3.3 The Plasma Membrane and How Substances Cross It
How does tonicity change a cell?
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
• __________ solutions
have more solute
than the inside
of the cell and lead to
crenation (shriveling).
H2O
c. Hypertonic solution
(higher solute concentration than in cell)
© Dennis Kunkel/Phototake
Figure 3.9c Effects of changes in tonicity on red blood cells.
4
3.3 The Plasma Membrane and How Substances Cross It
What are facilitated diffusion and
active transport?
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3. ________________
is the transport of
molecules across the
plasma membrane
from higher
concentration to
lower concentration
via a ____________.
Outside
K+
glucose
Figure 3.10 Facilitated transport across a cell membrane.
Inside
5
3.3 The Plasma Membrane and How Substances Cross It
What are facilitated diffusion and
active transport?
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
4. ________________ is
the movement of
molecules from a lower
to higher concentration
using ATP as ______; it
requires a protein
carrier.
Outside
K+
K+
K+
P
ATP
ADP
K+
Figure 3.11 Active transport and the sodium–potassium pump.
K+
Inside
6
3.3 The Plasma Membrane and How Substances Cross It
What are endocytosis
and exocytosis?
• 5. ___________ transports
molecules or cells into the cell
via invagination of the plasma
membrane to form a vesicle.
• 6. ____________ transports
molecules outside the cell via
the fusion of a vesicle with the
plasma membrane.
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plasma membrane
vacuole
a. Phagocytosis
solute
vesicle
b. Pinocytosis
receptor protein
solute
coated pit
Figure 3.12 Movement of large molecules across the membrane.
coated vesicle
c. Receptor-mediated endocytosis
7
3.4 The Nucleus and Endomembrane System
What structures are involved in
protein production?
• Nucleus
• Ribosomes
• Endomembrane system
8
3.4 The Nucleus and Endomembrane System
What is the structure and
function of the nucleus?
• Bound by a porous _______________
•
• Houses __________: DNA with associated
proteins
• Nucleolus contains ______________ (rRNA)
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3.4 The Nucleus and Endomembrane System
What is the structure and
function of ribosomes?
• Organelles made of rRNA and protein
• Found bound to the _________________
and free floating in the ____________
• Sites of protein synthesis
10
3.4 The Nucleus and Endomembrane System
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
nuclear
envelope
chromatin
nucleolus
rough ER
nuclear
pores
smooth ER
(nuclear pores): Courtesy E.G. Pollock; (ER): © R. Bolender & D. Fawcett/Visuals Unlimited
Figure 3.13 The nucleus and endoplasmic reticulum.
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3.4 The Nucleus and Endomembrane System
What is the endomembrane
system?
• It is a series of membranes in which molecules
are ____________ in the cell.
• It consists of the nuclear envelope, endoplasmic
reticulum, Golgi apparatus, lysosomes, and
vesicles.
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3.4 The Nucleus and Endomembrane System
How does the endomembrane system function?
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
secretion
plasma
membrane
secretory vesicle
incoming vesicle
enzyme
Golgi apparatus
modifies lipids and proteins
from the ER; sorts and packages
them in vesicles
lysosome
contains digestive enzymes
that break down cell parts or
substances entering by vesicles
protein
transport vesicle
takes proteins to
Golgi apparatus
transport vesicle
takes lipids to
Golgi apparatus
lipid
rough endoplasmic
reticulum
synthesizes proteins and
packages them in vesicles
smooth endoplasmic
reticulum
synthesizes lipids and has
various other functions
Nucleus
ribosome
Figure 3.14 The endomembrane system.
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3.4 The Nucleus and Endomembrane System
How can we summarize the parts
of the endomembrane system?
• Rough endoplasmic reticulum – studded with
ribosomes used to make ____________
• Smooth endoplasmic reticulum – lacks
ribosomes but aids in making ______________
and ________
• _____________ – flattened stacks that process,
package, and deliver proteins and lipids from the
ER
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3.4 The Nucleus and Endomembrane System
How can we summarize the parts
of the endomembrane system?
• ___________ – membranous vesicles made by
the Golgi that contain _________________
• ____________ – small membranous sacs used
for transport
15
3.6 Mitochondria and Cellular Metabolism
How can a cell make ATP without
oxygen?
• Fermentation:
– occurs in the _________.
– does not require ________.
– involves _________.
– makes 2 ATP and lactate in human cells.
– can give humans a burst of energy for a short
time.
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