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Cell Processes and Energy
Photosynthesis
Respiration
Cell Division
Cancer
Table of Contents
Cell Processes and Energy - Photosynthesis
Sources of Energy
Nearly all living things obtain energy either directly or indirectly from the energy of sunlight captured during photosynthesis.
Cell Processes and Energy
The Photosynthesis Process Activity
Click the Active Art button to open a browser window and access Active Art about the photosynthesis process.
- Photosynthesis
Cell Processes and Energy - Photosynthesis
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.
Cell Processes and Energy
SequencingSequence is the order in which the steps in a process occur. As you read, create a flowchart that shows the steps in photosynthesis. Put each step in a separate box in the flowchart in the order in which it occurs.
Steps in Photosynthesis
Sunlight strikes leaf.
Chlorophyll captures light energy.
Cells use the energy to produce sugars and oxygen from water and carbon dioxide.
- Photosynthesis
Cell Processes and Energy
Photosynthesis
Click the Video button to watch a movie about photosynthesis.
- Photosynthesis
Cell Processes and Energy
End of Section:Photosynthesis
Cell Processes and Energy - Respiration
Two Stages of Respiration
During respiration, cells break down simple food molecules such as sugar and release the energy they contain.
Cell Processes and Energy - Respiration
Photosynthesis and Respiration
You can think of photosynthesis and respiration as opposite processes.
Cell Processes and Energy
Using Prior KnowledgeYour prior knowledge is what you already know before you read about a topic. Before you read, write a definition of respiration in a graphic organizer like the one below. As you read, revise your definition based on what you learn.
Respiration is when an organism breathes in oxygen because oxygen is needed by cells.
Respiration also means the process in which cells break down simple food molecules such as sugar and release the energy they contain.
- Respiration
What You Know
What You Learned
Cell Processes and Energy
Respiration
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- Respiration
Cell Processes and Energy
Links on Cellular Respiration
Click the SciLinks button for links on cellular respiration.
- Respiration
Cell Processes and Energy
End of Section:Respiration
Cell Processes and Energy
Cell Division
• The cell cycle is the regular sequence of growth and division that cells undergo in order to maintain a functioning organism
• The cell cycle is divided into 3 main stages: interphase, mitosis, and cytokinesis
• Interphase takes the most time to complete and results in cell growth, copying of DNA (replication), and preparation to divide the original cell into 2 new cells
• Mitosis has 4 stages: prophase, metaphase, anaphase, and telophase. Upon completion, mitosis results in one copy of DNA being distributed into each of the two daughter cells.
• Cytokinesis results in cell division and the organelles being distributed into each of the two new cells. Cytokinesis is different in plant cells (a cell plate separates the 2 daughter cells
Cell Processes and Energy - Cell Division
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.
Cell Processes and Energy - Cell Division
The Cell Cycle
Cell Processes and Energy
Cell Cycle Activity
Click the Active Art button to open a browser window and access Active Art about the cell cycle.
- Cell Division
Cell Processes and Energy
Length of the Cell Cycle
How long does it take for a cell to go through one cell cycle? It all depends on the cell. A human liver cell, for example, completes one cell cycle in about 22 hours, as shown in the graph. Study the graph and then answer the following questions.
- Cell Division
Cell Processes and Energy
Length of the Cell Cycle
The longest curved arrow represents the cell’s interphase; the shortest represents cytokinesis; and the middle one represents mitosis.
Reading Graphs:
What do the three curved arrows outside the circle represent?
- Cell Division
Cell Processes and Energy
Length of the Cell Cycle
Interphase
Reading Graphs:
In what stage of the cell cycle is the wedge representing growth?
- Cell Division
Cell Processes and Energy
Length of the Cell Cycle
10 hours
Interpreting Data:
In human liver cells, how long does it take DNA replication to occur?
- Cell Division
Cell Processes and Energy
Length of the Cell Cycle
Interphase
Drawing Conclusions:
In human liver cells, what stage in the cell cycle takes the longest time?
- Cell Division
Cell Processes and Energy - Cell Division
Structure of DNA
The DNA molecule is shaped like a twisted ladder.
Cell Processes and Energy - Cell Division
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.
Cell Processes and Energy
SequencingAs you read, make a cycle diagram that shows the events in the cell cycle, including the phases of mitosis. Write each even in a separate circle.
The Cell Cycle
Cell grows, makes a copy of DNA.
Chromosomes and spindle fibers form; nuclear
envelope breaks down.
Chromosomes line up across the center and attach
to a spindle fiber.Centromeres split;
chromatids separate and move to opposite ends.
Chromosomes stretch out; new nuclear envelope forms
around chromosomes.
Cell pinches in two; each daughter cell has same number
of identical chromosomes.
- Cell Division
Cell Processes and Energy
End of Section:Cell Division
Cell Processes and Energy
Key Terminology
• Cancer is the general name for a group of more than 100 diseases in which cells in a part of the body begin to grow out of control. Although there are many kinds of cancer, they all start because abnormal cells grow out of control. Untreated cancers can cause serious illness and even death.
• Mutations occur when a portion of DNA is damaged in the replication process thus causing the cell to function abnormally
• A tumor or large mass of abnormal cells can result when these cells continue to divide and grow uncontrollably
Cell Processes and Energy - Cancer
What Is Cancer?
Cancer is a disease in which cells grow and divide uncontrollably, damaging the parts of the body around them.
Cell Processes and Energy
Cancer Treatment and Prevention
There are 3 common ways to treat cancer:
1. Surgury
2. Radiation
3. Medication
Chemotherapy is the use of chemicals to treat a disease.
*Prevention methods include eating healthy, exercising regularly, not smoking, and avoiding prolonged exposure to sunlight
Cell Processes and Energy
Previewing VisualsWhen you preview, you look ahead at the material to be read. Preview Figure 17. Then write two questions you have about the illustrations in a graphic organizer like the one below. As you read, answer your questions.
Q. What is a tumor?
A. A mass of abnormal cells that develops when cancerous cells divide and grow uncontrollably.
Q. How does cancer spread?
A. Some of the tumor cells can break off and enter the bloodstream.
How Cancer Spreads
- Cancer
Cell Processes and Energy
Links on Cancer
Click the SciLinks button for links on cancer.
- Cancer
Cell Processes and Energy
End of Section:Cancer
Cell Processes and Energy
Graphic Organizer
Comparing Photosynthesis and Respiration
Feature
Oxygen and sugars
Photosynthesis Respiration
Raw materials
Products
Is energy released?
Water and carbon dioxide
Yes
Oxygen and sugarsWater and carbon dioxide
No
Cell Processes and Energy
End of Section:Graphic Organizer
