Chapter 4 Cell Processes and Energy
Section 1: Photosynthesis
How does the sun supply living things with the
energy they need?
What happens during the process of
photosynthesis?
Chapter 4 Cell Processes and Energy
Sources of Energy
Nearly all living things obtain energy either directly or
indirectly from the energy of sunlight captured during
photosynthesis.
Chapter 4 Cell Processes and Energy
Autotroph vs. Heterotroph
Autotroph: any organism that makes its own food using the energy
of the sunlight captured by photosynthesis
Examples: plants, green algae
Heterotroph: an organism that can not make its own food, so it
must consume another organism for energy
Examples: animals, fungi, most bacteria
95% of all living organisms are heterotrophs.
Both autotrophs and heterotrophs get their energy from the sun.
Autotrophs get their energy DIRECTLY from the sun, while
heterotrophs get their energy INDIRECTLY.
Chapter 4 Cell Processes and Energy
The Two Stages of Photosynthesis
During photosynthesis, plants and some other
organisms use energy from the sun to convert
carbon dioxide and water into oxygen and sugars.
Chapter 4 Cell Processes and Energy
The Photosynthesis Equation
Chapter 4 Cell Processes and Energy
Breaking Down
the Photosynthesis Equation
Raw Materials: 6 CO2 + 6 H2O
Products: C6H12O6 + 6 O2
COO COO
HHO HHO
COO COO
HHO HHO
COO COO
HHO HHO
________________________
CCCCCC
OO OO
HHHHHH
OO OO
HHHHHH
OO OO
OOOOOO
________________________
6 Carbons +
12 Hydrogens + 18 Oxygens
6 Carbons +
12 Hydrogens + 18 Oxygens
Chapter 4 Cell Processes and Energy
End of Section:
Photosynthesis
Chapter 4 Cell Processes and Energy
Section 2: Cellular Respiration
•
•
What events occur during cellular respiration?
What is fermentation?
Chapter 4 Cell Processes and Energy
Two Stages of Cellular Respiration
Cellular Respiration: A process where cells break down simple
food molecules such as sugar and release the energy they contain.
Chapter 4 Cell Processes and Energy
The Cellular Respiration Equation
Chapter 4 Cell Processes and Energy
Photosynthesis and Respiration
You can think of photosynthesis and cellular respiration as
opposite processes.
Chapter 4 Cell Processes and Energy
Fermentation
Fermentation: A process that provides cells with energy
without using oxygen.
• Alcoholic Fermentation: Occurs in yeast and
other one-celled organisms. This is the process
used to make yeast turn grape juice into wine.
• Lactic Acid Fermentation: Occurs in humans
and other animals when they exercise and there
is a lack of oxygen. This leads the acid taste in
your mouth and sore muscles.
Chapter 4 Cell Processes and Energy
End of Section:
Respiration
Chapter 4 Cell Processes and Energy
Section 3: Cell Division
What events take place during the three
states of the cell cycle?
How does the structure of DNA help account
for the way in which DNA copies itself?
Chapter 4 Cell Processes and Energy
The Cell Cycle
Cell Cycle: The regular sequence of growth and division that
cells undergo.
Made up of 3 stages:
•
•
•
Stage 1: Interphase
Stage 2: Mitosis
Stage 3: Cytokinesis
Chapter 4 Cell Processes and Energy
Interphase
Cells spend most of their time in this phase.
During Interphase, the following 5 events will occur:
•
•
•
•
•
The cell will perform its “normal” functions and
duties.
The cell will grow to about twice it's original size.
The cell's organelles will make copies of
themselves and double in quantity.
The cell's DNA will make a copy of itself right
before Mitosis begins.
Once the DNA is copied, the cell will make
structures that it will use to help divide itself.
Chapter 4 Cell Processes and Energy
Mitosis
During mitosis, the cell’s nucleus divides into two new nuclei.
One copy of the DNA is distributed into each of the two
daughter cells.
Chapter 4 Cell Processes and Energy
Mitosis
Four stages in Mitosis:
• Prophase
• Metaphase
• Anaphase
• Telophase
Chapter 4 Cell Processes and Energy
Mitosis: Prophase
“Chromatin” winds up into
a condensed shape
called “chromatid”.
Chromatin: unwound DNA
Chromatid: wound DNA
Chapter 4 Cell Processes and Energy
Mitosis: Prophase
The cell gets ready for the
“Tug of War” activity that
occurs in Mitosis.
Chapter 4 Cell Processes and Energy
Mitosis: Prophase
The cell gets ready for the
“Tug of War” activity that
occurs in Mitosis.
The pair of centrioles move
to opposite sides of the
nucleus.
Spindle fibers (the “ropes”)
form between the
centrioles.
The nuclear envelope that
surrounds the nucleus
breaks down.
Chapter 4 Cell Processes and Energy
Mitosis: Metaphase
The chromatids line up on
the equator of the cell.
Chapter 4 Cell Processes and Energy
Mitosis: Anaphase
The chromatids separate
and move to opposite
sides of the cell.
The cell starts to stretch
apart as it gets ready
for Cytokinesis.
Chapter 4 Cell Processes and Energy
Mitosis: Telophase
Chromatids unwind and
return to their string-like
chromatin shape.
2 new nuclear envelopes
form to make 2 new
nuclei.
Chapter 4 Cell Processes and Energy
Cytokinesis
Must finish after Mitosis or
else the cell will split into 2
cells before the DNA is
evenly divided.
The 2 new cells are called
“daughter cells”.
Each daughter cell is identical
to the original parent cell.
Chapter 4 Cell Processes and Energy
The Cell Cycle
Chapter 4 Cell Processes and Energy
D.N.A.
D.N.A. stands for
Deoxyribonucleic Acid.
D.N.A. is the “instruction
manual” or “blueprint” of
all living things.
Chapter 4 Cell Processes and Energy
D.N.A.
A single strand of D.N.A. in each cell is about 6 feet
long. Multiplied by all the cells in your body, you have
enough D.N.A. to go to the Sun and back about 70 times
(the Sun is 93 million miles away).
Chapter 4 Cell Processes and Energy
D.N.A.
D.N.A.'s unique shape was discovered by James Watson
and Francis Crick in 1953, with help from Maurice Wilkins
and Rosalind Franklin.
Chapter 4 Cell Processes and Energy
D.N.A.
D.N.A. has a double helix structure,
which resembles a spiral staircase.
Chapter 4 Cell Processes and Energy
D.N.A.
The sides of the twisted
D.N.A. ladder are made
up of a sugar called
deoxyribose. In between
the deoxyribose sugars
is a molecule called
phosphate.
Chapter 4 Cell Processes and Energy
D.N.A.
The rungs (steps) of the D.N.A. ladder is where we find
the “blueprint” information. These rungs are made up of
only 4 types of nitrogen bases:
•
•
Thymine (T)
Adenine (A)
•
•
Guanine (G)
Cytosine (C)
Chapter 4 Cell Processes and Energy
D.N.A.
Each rung of the D.N.A. ladder is made up
of a pair of nitrogen bases.
Adenine (A) only pairs up with Thymine (T).
Guanine (G) only pairs up with Cytosine (C).
Chapter 4 Cell Processes and Energy
D.N.A.
D.N.A. is able to make copies of itself by “unzipping”
and filling in the blanks with matching bases.
Chapter 4 Cell Processes and Energy
Structure of DNA
The DNA molecule, supported by proteins, is
shaped like a twisted ladder.
Chapter 4 Cell Processes and Energy
Replication of DNA
Because of the way in which the nitrogen bases pair with one
another, the order of the bases in each new DNA molecule
exactly matches the order in the original DNA molecule.
Chapter 4 Cell Processes and Energy
End of Section:
Cell Division
Chapter 4 Cell Processes and Energy
Section 4:
Cell Differentiation
What is differentiation?
What factors influence how and when cells
differentiate within different organisms?
Chapter 4 Cell Processes and Energy
Specialized Cells
Leaf cell
Undifferentiated
plant cell
Plants have undifferentiated
cells in their stems and roots
that can give rise to different
kinds of cells.
Transport cell
Root cell
Chapter 4 Cell Processes and Energy
End of Section:
Cell Differentiation