SECTION
3.5
ACTIVE TRANSPORI ENDOCYTOSIS, AND EXOCYTOSIS
Study Guide
KEY CONCEPT
VOCABULARY
Cells use energy to transport materials that cannot diffuse
across a membrane.
MAIN IDEA: Proteins
gocytosis
active transport
ph
endocytosis
exocytosis
a
can transport materials against a concentration gradient.
1. How is active transport different than simple difñ;sion and facilitated diffusion?
2.
Active transport is the movement of molecules against a concentration gradient, whereas any type of d
rs the movement ol molecu les oown a concentratton gradtent.
How is active transport similar to facilitated diffusion?
Both involve the movement of molecules through selective membrane proteins
3.
List two characteristics that almost all transport proteins share
All transoort oroteins soan the membrane, and most chanqe shape when they bind to a tarqet molecule
or molecules.
4.
List the key distinguishing feature of active transport proteins.
Active transport proteins use chemical energy to move a substance âqainst its concentration gradient.
5. Refer to Figure
3.25 to draw a picture in the box below to represent active transport.
outs¡de
inside
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6.
Most active transport proteins use energy from the breakdown
of
ATP
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Unit 2 Fesource Book
N/cDougal Littell Biology
Study Guide 17
Period
Name
Date
STUDY GUIDE, CONTINUED
MAIN IDEA: Endocytosis and exocytosis transport materials across the membrane
in vesicles.
7. A cell may transport
a substance in
vesicles
if the substance is
too large to cross the membrane.
8.
During endocytosis, the vesicle membrane fuses with a lysosome, and the membrane
and its contents are broken down by
lysosomal enzymes
Complete the Y diagram below to compare and contrast the processes of endocytosis and
exocytosis. Under the heading "endocytosis," list the characteristics of endocytosis. Under
the heading "exoc¡rtosis," list the characteristics of exoc¡osis. At the bottom of the I
write the characteristics that both processes have in common. Then lightly cross out those
characteristics at the top of the Y.
Exocytosis
Endocytosis
uses energy, takes substances into a
uses energy, releases substances
cell, moves substances in vesicles
outside a cell, moves substances in
vesicles
B
oth
use energy, move substances in vesicles
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C
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O
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=Co
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Vocabulary Gheck
9.
-o
õ
:
What term means "cell eating" and describes a type of endocytosis?
Phagocystosis
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f
1O. The prefix exo- means "out of," and the prefix endo- means "taking in." How do these
meanings relate to the meaning of exocytosis and endocytosis?
o)
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o
o
Endocytosis is a process that takes substances into a cell.
11. What process drives molecules across a membrane against a concentration gradient?
Active transport.
study Guide
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T
Exocytosis is a process that releases substances outside a cell.
18
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Unit 2 Besource Book
McDougal Littell Biology