Transcript Prentice Hall Biology

Interest Grabber
Section 7-1
Are All Cells Alike?
All living things are made up of cells. Some organisms are composed of only
one cell. Other organisms are made up of many cells.
1. What are the advantages of a one-celled organism?
2. What are the advantages of an organism that is made up of many cells?
Go to
Section:
7-1 Life is Cellular
Leeuwenhoek – invented the microscope; observed pond water
Robert Hooke – first scientist to observe a cell. He used a compound light
microscope to observe cork.
Schleiden – stated that all plants are composed of cells.
Schwann – stated that all animals are made of cells.
Go to
Section:
The Cell Theory
All organisms are composed of one or more
cells.
The cell is the basic unit of structure and
function in all living organisms.
All cells come from preexisting cells.
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Section:
Prokaryotes and Eukaryotes
Prokaryotes – do not contain a nucleus;
bacteria in the Monera kingdom.
Eukaryotes – contain a nucleus; all other
kingdoms.
Go to
Section:
Prokaryotic and Eukaryotic Cells
Section 7-1
Cell membrane
Cytoplasm
Prokaryotic Cell
Cell membrane
Cytoplasm
Nucleus
Eukaryotic Cell
Organelles
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Section:
7-2 Eukaryotic Cell Structure
nucleus (control center) - large dark
structure; some unicellular organisms like
bacteria do not have a nuclei.
a. prokaryotes - lack a nucleus
b. eukaryotes - contain a nucleus
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Section:
The Nucleus
The nucleus is the information center of the cell and contains DNA;
directs all activities in a cell. It contains two membranes that form
the nuclear envelope. Nuclear envelope contains dozens of pores
for molecules to move in and out. Nucleolus - made of RNA and
proteins; where ribosomes are made.
chromosomes - DNA forms these in eukaryotic cells; they contain
the genetic information that must be passed to each new
generation of cells.
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Section:
Ribosomes and Endoplasmic Reticulum
ribosomes - structures where proteins are made. (composed of
RNA and protein)
endoplasmic reticulum - complex network of sacs that transport
materials inside the cell; site of cellular chemical reactions
a) smooth ER - special enzymes and chemicals may
be stored here
b) rough ER - responsible for the synthesis of proteins
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Section:
Golgi Apparatus, Lysosomes, and Vacuoles
Golgi apparatus - modifies, collects, packages, and distributes molecules
in a cell.
Lysosomes - small membrane bordered structures necessary for
digesting certain materials in a cell.
Vacuoles - store materials such as water, salts, proteins, and
carbohydrates.
Go to
Section:
Mitochondria and Chloroplasts
mitochondria and chloroplasts - change
energy from one form to another.
Mitochondria change chemical energy stored
in food into compounds. Chloroplasts trap
the energy of sunlight and convert to
chemical energy; found only in plants and
algae.
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Section:
Cytoskeleton
cytoskeleton - composed of a variety of filaments and fibers that
support cell structure and drive cell movement.
a) microtubules – thin, hollow cylinders made of protein;
important in cell division by forming centrioles (animal
cells); some contain cilia (short hairlike projections that
help movement) and flagella (longer whiplike structures
that help unicellular organisms move about)
b) microfilaments - long thin fibers that function in the
movement and support of the cell.
Go to
Section:
7-3 Cell Boundaries
cell membrane – the boundary between the cell and its
environment. It allows the steady flow of nutrients to come into
and out of the cell.
cell wall - found in plants, algae, and some bacteria; The plasma
membrane is surrounded by a cell wall. It helps to protect and
support the cell.
selective permeability – a process in which the cell membrane of
a cell allows some molecules into the cell while keeping others
out.
Go to
Section:
Venn Diagrams
Section 7-2
Prokaryotes
Eukaryotes
Cell membrane
Contain DNA
Animal Cells
Centrioles
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Section:
Plant Cells
Cell membrane
Ribosomes
Nucleus
Endoplasmic reticulum
Golgi apparatus
Lysosomes
Vacuoles
Mitochondria
Cytoskeleton
Cell Wall
Chloroplasts
Nucleus
Endoplasmic reticulum
Golgi apparatus
Lysosomes
Vacuoles
Mitochondria
Cytoskeleton
Figure 7-5 Plant and Animal Cells
Section 7-2
Smooth endoplasmic
reticulum
Vacuole
Ribosome
(free)
Chloroplast
Ribosome
(attached)
Cell
Membrane
Nuclear
envelope
Cell wall
Nucleolus
Golgi apparatus
Nucleus
Mitochondrion
Rough endoplasmic reticulum
Plant Cell
Go to
Section:
Figure 7-5 Plant and Animal Cells
Section 7-2
Nucleolus
Nucleus
Ribosome
(attached)
Nuclear
envelope
Mitochondrion
Smooth
endoplasmic
reticulum
Rough
endoplasmic
reticulum
Centrioles
Golgi apparatus
Animal Cell
Go to
Section:
Ribosome
(free)
Cell
Membrane
Figure 7-11 Cytoskeleton
Section 7-2
Cell membrane
Endoplasmic
reticulum
Microtubule
Microfilament
Ribosomes
Go to
Section:
Mitochondrion
Interest Grabber
Section 7-3
In or Out?
How is a window screen similar to a cell membrane? Read on to find out.
1. What are some things that can pass through a window screen?
2. What are some things that cannot pass through a window screen? Why
is it important to keep these things from moving through the screen?
3. The cell is surrounded by a cell membrane, which regulates what enters
and leaves the cell. Why is it important to regulate what moves into and
out of a cell?
Go to
Section:
Movement Into and Out of the Cell
Diffusion – the movement of particles
from an area of high concentration to an
area of low concentration
Osmosis – the diffusion of water across a
selectively permeable membrane.
Go to
Section:
How Osmosis Works
Isotonic solution – the concentration of dissolved substances in the
solution is the same as the concentration of dissolved substances inside
the cell. (same strength)
Hypotonic solution – the concentration of dissolved substances is lower
in the solution outside the cell than the concentration inside the cell.
Therefore, there is more water outside the cell than inside. This will cause
the water to flow into the cell. (above strength)
Hypertonic solution – the concentration of dissolved substances outside
the cell is higher than the concentration inside the cell. Cells in the
hypertonic solution experience osmosis that causes water to flow out.
(below strength)
Go to
Section:
Figure 7-15 Osmosis
Section 7-3
Go to
Section:
Facilitated Diffusion
The diffusion of particles
across a membrane with the
help of a carrier protein.
Go to
Section:
Facilitated Diffusion
Section 7-3
Glucose
molecules
High
Concentration
Cell
Membrane
Low
Concentration
Go to
Section:
Protein
channel
Figure 7-12 The Structure of the
Cell Membrane
Section 7-3
Outside
of cell
Proteins
Carbohydrate
chains
Cell
membrane
Inside
of cell
(cytoplasm)
Go to
Section:
Protein
channel
Lipid bilayer
Passive and Active Transport
Passive Transport – when the cells use no
energy to move particles. (Diffusion, Osmosis,
and Facilitated Diffusion) Facilitated diffusion is
the transport of molecules across the
membrane by transport proteins.
Active Transport – movement of materials
through a membrane against a concentration
gradient. It requires energy from the cell.
Go to
Section:
Figure 7-19 Active Transport
Section 7-3
Molecule to
be carried
Energy
Molecule
being carried
Go to
Section:
Interest Grabber
Section 7-4
From Simple to More Complex
Many multicellular organisms have structures called organs that have a
specific function and work with other organs. Working together, these
organs carry out the life processes of the entire organism.
Go to
Section:
Interest Grabber continued
Section 7-4
1. Some activities cannot be performed by only one person, but need a
team of people. What type of activity requires a team of people to work
together in order to complete a task?
2. What do you think are some characteristics of a successful team?
3. How is a multicellular organism similar to a successful team?
Go to
Section:
7-4 The Diversity of Cellular Life
Cell Specialization – the process where cells
throughout an organism develop in different ways to
perform different tasks.
Cells  Tissues  Organs  Organ Systems
Go to
Section:
Levels of Organization
Section 7-4
Muscle cell
Go to
Section:
Smooth muscle tissue
Stomach
Digestive system
Videos
Click a hyperlink to choose a video.
Diffusion
Osmosis
Passive Transport
Active Transport
Endocytosis and Exocytosis
Video 1
Diffusion
Click the image to play the video segment.
Video 2
Osmosis
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Video 3
Passive Transport
Click the image to play the video segment.
Video 4
Active Transport
Click the image to play the video segment.
Video 5
Endocytosis and Exocytosis
Click the image to play the video segment.
Go Online
The latest discoveries in cell study
Cell structure activity
Career links on histotechnologists
Interactive test
Articles on cells
For links on cell theory, go to www.SciLinks.org and enter the
Web Code as follows: cbn-3071.
For links on cell membranes, go to www.SciLinks.org and enter the
Web Code as follows: cbn-3073.
Interest Grabber Answers
1. What are the advantages of a one-celled organism?
A one-celled organism has simpler needs and can respond immediately to
its environment because its entire cell is immersed in its environment.
2. What are the advantages of an organism that is made up of many cells?
In a multicellular organism, different jobs are divided among different
groups of cells that work together. Also, a multicellular organism can
continue to survive even if it loses some of its cells.
Interest Grabber Answers
Working with a partner, answer the following questions.
1. What are some of the different parts of a computer? What are the functions
of these computer parts?
Answers may include: monitor (interfaces with the computer’s
environment), software (instructions for how to carry out different jobs),
CPU (directs the computer's activities), recycle bin or trash can (storage
area for wastes), and so on.
2. How do the functions of these computer parts correspond to the functions
of certain cell parts?
Students should try to link the functions they described in question 1 to the
functions of the different cell structures. The cell needs a way to interface
with its environment (cell membrane), instructions for carrying out different
jobs (DNA), and a CPU to direct the cell’s activities (nucleus).
Interest Grabber Answers
1. What are some things that can pass through a window screen?
Answers may include air, fine dust, and rainwater.
2. What are some things that cannot pass through a window screen? Why is
it important to keep these things from moving through the screen?
Insects, leaves, and other matter that may fall from trees. The screen
keeps out annoying insects and objects that may bring dirt into the home.
3. The cell is surrounded by a cell membrane, which regulates what enters
and leaves the cell. Why is it important to regulate what moves into and out
of a cell?
Materials such as oxygen and food that are needed by the cell have to be
able to get inside the cell. At the same time, excess materials have to leave
the cell.
Interest Grabber Answers
1. Some activities cannot be performed by only one person, but need a team
of people. What type of activity requires a team of people to work together
in order to complete a task?
Answers might include building a human pyramid or constructing an arch
out of blocks.
2. What do you think are some characteristics of a successful team?
Divide up jobs and cooperate well with one another.
3. How is a multicellular organism similar to a successful team?
The functions of the organism are divided up among its parts (organs and
organ systems). All the parts cooperate to carry out all the functions of the
whole organism.
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