Transcript Living Things

Cell Structure and Function
Table of Contents
Discovering Cells
Looking Inside Cells
Chemical Compounds in Cells
The Cell in Its Environment
Cell Structure and Function - Discovering Cells
Development of the Cell Theory
The cell theory states the following:
• All living things are composed of cells.
• Cells are the basic units of structure and function in living things.
• All cells are produced from other cells.
Cell Structure and Function - Discovering Cells
Light Microscopes
The lenses in light microscopes magnify an object by
bending the light that passes through them.
Cell Structure and Function - Discovering Cells
Sequencing
Construct a flowchart showing how the work of Hooke,
Leeuwenhoek, Schleiden, Schwann, and Virchow contributed
to scientific understanding of cells.
Discovering Cells
Hooke sees cells in cork.
Leeuwenhoek sees many one-celled organisms.
Schleiden concludes that all plants are made of cells.
Schwann concludes that all animals (and all living
things) are made of cells.
Virchow proposes that new cells form only from cells
that already exist.
Cell Structure and Function
End of Section:
Discovering
Cells
Cell Structure and Function - Looking Inside Cells
Nucleus
The nucleus is the cell’s control center, directing all of the
cell’s activities.
Cell Structure and Function - Looking Inside Cells
Mitochondrion
Mitochondria are known as the “powerhouses” of the cell
because they convert energy in food molecules to energy the
cell can use to carry out its functions.
Cell Structure and Function - Looking Inside Cells
Endoplasmic Reticulum
The endoplasmic reticulum is similar to the system of
hallways in a building. Proteins and other materials move
throughout the cell by way of the endoplasmic reticulum. The
spots on this organelle are ribosomes, which produce
proteins.
Cell Structure and Function - Looking Inside Cells
Plant and Animal Cells
Cell Structure and Function - Looking Inside Cells
Golgi Body
The Golgi bodies receive proteins and other newly formed
materials from the endoplasmic reticulum, package them,
and distribute them to other parts of the cell.
Cell Structure and Function - Looking Inside Cells
Plant and Animal Cells Activity
Click the Active Art button to open a browser window and
access Active Art about plant and animal cells.
Cell Structure and Function - Looking Inside Cells
Previewing Visuals
Before you read, preview Figure 12. Then write two
questions you have about the illustrations in a graphic
organizer like the one below. As you read, answer your
questions.
Plant and Animal Cells
Q. How are animal cells different from plant cells?
A. Plants cells have a cell wall and chloroplasts, which animal
cells to not have.
Q. What do mitochondria do?
A. Mitochondria convert energy in food molecules to energy the
cell can use.
Cell Structure and Function
End of Section:
Looking Inside
Cells
Cell Structure and Function - Chemical Compounds in Cells
Elements and Compounds
Carbon dioxide, which is found in gas bubbles, is a chemical
compound. So is water.
Cell Structure and Function - Chemical Compounds in Cells
Compounds in Bacteria and Mammals
All cells contain carbohydrates,
lipids, proteins, and nucleic
acids, as well as water and other
inorganic compounds. But do all
cells contain the same
percentages of these
compounds? The graph
compares the percentage of
some compounds found in a
bacterial cell and a cell from a
mammal.
Cell Structure and Function - Chemical Compounds in Cells
Compounds in Bacteria and Mammals
Reading Graphs:
What do the red bars
represent? What do the blue
bars represent?
Red bars represent
percentages of compounds in
bacterial cells; blue bars
represent percentages of
compounds in mammalian
cells.
Cell Structure and Function - Chemical Compounds in Cells
Compounds in Bacteria and Mammals
Interpreting Data:
What percentage of a
mammalian cell is made up of
water? How does this
compare to the percentage of
water in a bacterial cell?
About 70%; the percentages
are the same.
Cell Structure and Function - Chemical Compounds in Cells
Compounds in Bacteria and Mammals
Interpreting Data:
Which kind of compound–
proteins or nucleic acids–
makes up the larger
percentage of a mammalian
cell?
Proteins
Cell Structure and Function - Chemical Compounds in Cells
Compounds in Bacteria and Mammals
Drawing Conclusions:
In general, how do a bacterial
cell and mammalian cell
compare in their chemical
composition?
They are similar, though
mammalian cells have a
lower percentage of nucleic
acids, and bacterial cells have
a lower percentage of lipids
and fewer proteins.
Cell Structure and Function - Chemical Compounds in Cells
Water and Living Things
About two-thirds of the human body is
water.
Cell Structure and Function - Chemical Compounds in Cells
Comparing and Contrasting
As you read, compare and contrast carbohydrates, proteins,
and lipids in a table like the one below.
Type of
Compound
Carbohydrate
Protein
Lipid
Elements
Carbon, hydrogen,
oxygen
Carbon, hydrogen,
oxygen, nitrogen, and
sometimes sulfur
Carbon, hydrogen,
oxygen
Functions
Store and provide
energy and make up
cellular parts
Make up much of the
structure of cells and
speed up chemical
reactions
Store energy
Cell Structure and Function - Chemical Compounds in Cells
Links on Proteins
Click the SciLinks button for links on proteins.
Cell Structure and Function
End of Section:
Chemical
Compounds in
Cells
Cell Structure and Function - The Cell in Its Environment
Ratios
The concentration of a solution can be expressed as a ratio.
A ratio compares two numbers. It tells you how much you
have of one item in comparison to another. For example,
suppose you dissolve 5 g of sugar in 1 L of water. You can
express the concentration of the solution in ratio form as
5 g:1 L, or 5 g/L.
Practice Problem
Suppose you dissolve 7 g of salt in 1 L of water. Express the
concentration of the solution as a ratio.
7 g:1 L or 7 g/L
Cell Structure and Function - The Cell in Its Environment
A Selective Barrier
The cell membrane protects the contents of the cell and
helps control the materials that enter and leave.
Cell Structure and Function - The Cell in Its Environment
Diffusion
In diffusion, molecules move from an area of higher
concentration to an area of lower concentration. Molecules
will reach equilibrium. Where their concentration is equal.
Cell Structure and Function - The Cell in Its Environment
Osmosis
In osmosis, water diffuses through a selectively permeable
membrane. (Usually the Cell Membrane)
Cell Structure and Function - The Cell in Its Environment
Passive and
Active Transport
Passive and active transport
are two processes by which
materials pass through the cell
membrane. Active transport
requires the cell to use its own
energy, while passive transport
does not.
Cell Structure and Function - The Cell in Its Environment
Building Vocabulary
A definition states the meaning of a word or phrase. After you
read the section, reread the paragraphs that contain
definitions of Key Terms. Use all the information you have
learned to write a definition of each Key Term in your own
words.
Key Terms:
selectively
passive
transport
permeable
diffusion
active transport
osmosis
Examples:
The movement
cell membrane
of dissolved
is selectively
materials
permeable,
through awhich
cell
means that without
membrane
some substances
using cellular
canenergy
pass through
is calledthe
membrane
passive
transport.
while others cannot.
Diffusion
is the process
by which molecules
move
Active transport
is the movement
of materials
from
an a
area
higher concentration
to energy.
an area of
through
cellof
membrane
using cellular
lower concentration.
Osmosis is the diffusion of water molecules through a
selectively permeable membrane.
Cell Structure and Function - The Cell in Its Environment
More on Cellular Transport
Click the PHSchool.com button for an activity
about cellular transport.
Cell Structure and Function
End of Section:
The Cell in Its
Environment
Cell Structure and Function
Graphic Organizer
Organic
Compounds
types
Carbohydrates
Lipids
Proteins
Nucleic
acids
include
include
made of
types
Fats, oils,
and waxes
Amino
acids
Sugars
Starches
DNA
RNA
Cell Structure and Function
End of Section:
Graphic Organizer