Transcript Chapt03 Lecture 13ed Pt 4

Human Biology
Sylvia S. Mader
Michael Windelspecht
Chapter 3
Cell Structure
and Function
Lecture Outline
Part 4
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1
3.5 The Cytoskeleton, Cell Movement, and Cell Junctions
What is the cytoskeleton?
• A series of proteins that maintain cell shape, as
well as anchors and/or moves organelles in the
cell
• Made of 3 types of fibers: large microtubules,
thin _______________, and medium-sized
intermediate filaments
2
3.5 The Cytoskeleton, Cell Movement, and Cell Junctions
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What are cilia and flagella?
Flagellum
microtubules
plasma
membrane
• Both are made of
microtubules.
a.
cilia
• Both are used in
___________.
sperm
flagellum
secretory cell
• Cilia are about 20
shorter than flagella.
b.
flagellum
Figure 3.15 Structure and function of the cilia
and flagella.
c.
(b): © Y. Nikas/Photo Researchers, Inc.; (c): © David M. Phillips/Photo Researchers, Inc.
3
3.5 The Cytoskeleton, Cell Movement, and Cell Junctions
What are cell junctions?
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• Junctions between the
cells of human tissue
that allow them to
function in a
coordinated manner
filaments of
• 3 main types
cytoskeleton
– ______________
mechanically attach
adjacent cells
(common in skin
cells).
plasma
membranes
intercellular
filaments
intercellular
space
a. Adhesion junction
Figure 3.16a Junctions between cells.
4
3.5 The Cytoskeleton, Cell Movement, and Cell Junctions
What are cell junctions?
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
– _____________ are
connections between
the plasma
membrane proteins
of neighboring cells
that produce a
____________
barrier (common in
digestive system and
kidney where fluids
must be contained to
a specific area).
plasma
membranes
tight junction
proteins
intercellular
space
b. Tight junction
Figure 3.16b Junctions between cells.
5
3.5 The Cytoskeleton, Cell Movement, and Cell Junctions
What are cell junctions?
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
– ____________ are
communication
portals between
cells; channel
proteins of the
plasma membrane
fuse, allowing easy
movement between
adjacent cells.
plasma
membranes
membrane
channels
intercellular
space
c. Gap junction
Figure 3.16c Junctions between cells.
6
3.6 Mitochondria and Cellular Metabolism
What do mitochondria do and what do
they look like?
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• Highly folded
organelles in
eukaryotic cells
• Produce _______ in
the form of ____
outer
membrane
intermembrane inner
space
membrane
matrix
200 nm
cristae
• Thought to be derived
from an engulfed
prokaryotic cell
Figure 3.17 The structure of a mitochondrion.
(top) : © Dr. Don W. Fawcett/Visuals Unlimited
7
3.6 Mitochondria and Cellular Metabolism
Enzymes are important for cellular
respiration and many activities in the cell
• Most enzymes are ________.
• Enzymes are often named for the molecules that
they work on, called ___________.
• Enzymes are __________ to what substrate they
work on.
• Enzymes have active sites where a substrate binds.
• Enzymes are not used up in a reaction but instead
are ___________.
• Some enzymes are aided by nonprotein molecules
called coenzymes.
8
3.6 Mitochondria and Cellular Metabolism
How do enzymes work?
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products
product
enzyme
enzyme
substrates
substrate
enzyme–substrate
complex
enzyme–substrate
complex
active site
Degradation
A substrate is broken
down to smaller products.
enzyme
active site
Synthesis
Substrates are combined
to produce a larger product.
enzyme
Figure 3.18 Action of an enzyme.
9
3.6 Mitochondria and Cellular Metabolism
What is cellular respiration?
•
Production of _____ in a cell
•
Includes
1. Glycolysis
2. Citric acid cycle (Krebs cycle)
3. Electron transport chain
10
3.6 Mitochondria and Cellular Metabolism
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Inside cell
electrons
transferred
by NADH
glucose
electrons
transferred
by NADH
Glycolysis
glucose
Citric
acid
cycle
pyruvate
Electron
transport
chain
oxygen
mitochondrion
2
ATP
2
ATP
32
ATP
Outside cell
Figure 3.19 Production of ATP.
11
3.6 Mitochondria and cellular metabolism
Glycolysis
– Occurs in the _________
– Breaks ________ into 2 pyruvate
– NADH and 2 ATP molecules are made
– Does not require __________
12
3.6 Mitochondria and Cellular Metabolism
Citric acid cycle (Krebs cycle)
– A cyclical pathway that occurs in the
____________
– Produces NADH and 2 ATP
– Releases carbon dioxide
13
3.6 Mitochondria and Cellular Metabolism
Electron transport chain
• Series of molecules embedded in the
mitochondrial membrane
– NADH made in steps 1 and 2 carry electrons
here
– ___________ are made depending on the cell
– Requires __________ as the final electron
acceptor in the chain
14
3.6 Mitochondria and Cellular Metabolism
What other molecules besides glucose
can be used in cellular respiration?
• Other carbohydrates
• Proteins
• Lipids
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.
16