Campbell: Biology
Twelfth Edition
Chapter 7
Membrane Structure and
Function
Copyright © 2021, 2017, 2014 Pearson Education, Inc. All Rights Reserved
,How does the plasma membrane regulate
inbound and outbound traffic?
• Some small molecules move across the cell membrane
using passive transport—no input of energy—and may
require transport proteins
• Some small molecules use active transport, which
requires both energy and a transport protein
• Large molecules move in and out, using bulk transport;
exocytosis or endocytosis
Copyright © 2021, 2017, 2014 Pearson Education, Inc. All Rights Reserved.
,Figure 7.1b How does the plasma membrane
regulate inbound and outbound traffic?
Copyright © 2021, 2017, 2014 Pearson Education, Inc. All Rights Reserved.
, CONCEPT 7.1: Cellular membranes
are fluid mosaics of lipids and
proteins (1 of 3)
• Lipids and proteins are the main components of
membranes, but carbohydrates are also important
• Membranes are composed mainly of phospholipids
• Phospholipids are amphipathic molecules, containing
hydrophobic (“water-fearing”) and hydrophilic (“water-
loving”) regions
Copyright © 2021, 2017, 2014 Pearson Education, Inc. All Rights Reserved.
Twelfth Edition
Chapter 7
Membrane Structure and
Function
Copyright © 2021, 2017, 2014 Pearson Education, Inc. All Rights Reserved
,How does the plasma membrane regulate
inbound and outbound traffic?
• Some small molecules move across the cell membrane
using passive transport—no input of energy—and may
require transport proteins
• Some small molecules use active transport, which
requires both energy and a transport protein
• Large molecules move in and out, using bulk transport;
exocytosis or endocytosis
Copyright © 2021, 2017, 2014 Pearson Education, Inc. All Rights Reserved.
,Figure 7.1b How does the plasma membrane
regulate inbound and outbound traffic?
Copyright © 2021, 2017, 2014 Pearson Education, Inc. All Rights Reserved.
, CONCEPT 7.1: Cellular membranes
are fluid mosaics of lipids and
proteins (1 of 3)
• Lipids and proteins are the main components of
membranes, but carbohydrates are also important
• Membranes are composed mainly of phospholipids
• Phospholipids are amphipathic molecules, containing
hydrophobic (“water-fearing”) and hydrophilic (“water-
loving”) regions
Copyright © 2021, 2017, 2014 Pearson Education, Inc. All Rights Reserved.
