Cell Processes and Energy Chapter 4

Chapter 4 Vocabulary Words Photosynthesis Chlorophyll Respiration Cell Cycle Interphase Mitosis Chromosomes Cytokinesis DNA Differentiation

Photosynthesis Chapter 4 Section 1

Photosynthesis Almost all living things obtain (get) energy either directly or indirectly from sunlight during photosynthesis.

Photosynthesis Almost all living things obtain (get) energy either directly or indirectly from sunlight during photosynthesis.

Photosynthesis is what happens when plant cells turn sunlight into food. Plants get energy directly from sunlight Animals get energy by eating plants or eating other animals that eat plants. So animals get the sun’s energy indirectly.

If you make your own food you are called an autotroph organism. If you cannot make your own food from the sun’s energy you are heterotroph. Which one are you?

Two stages of Photosynthesis Stage 1- Capturing the Sun’s Energy Plants use a chemical pigment in chloroplast called chlorophyll to absorb sunlight. It works a lot like a solar calculator. Chlorophyll is the pigment that makes leaves look green. What color is the pigment reflecting?

Stage 2- Use that Energy to make Food The captured energy is used to produce sugars. The plant will need water and carbon dioxide to do this. Water it will get from its roots, Carbon Dioxide it will bring in through its stomata. Stomata (stoma) are tiny holes under leaves that open when leaves need to receive CO2 or release O2.

Sugar = C6 H12 O6 Water (H2O)and Carbon Dioxide (CO2) enter the leaf and use sunlight to power a chemical reaction that produces a type of carbohydrate called sugar (C6 H12 O6). Besides sugar the plant cells also produce Oxygen….good thing for us.

The Photosynthesis Equation light energy 6 CO2 + 6 H2O C6H12O6 + 6 O2 “yields” This produces 1 molecule of Sugar and 6 molecules of Oxygen. The cells break the sugars down to release the energy. Any extra sugar is converted to cellulose and stored for later.

Cellular Respiration Chapter 4 Section 2

What is Respiration? During respiration, cells break down simple food molecules such as sugar and release the energy they contain. This is how cells get energy

Respiration takes place in plant and animal cells ALL the time because cells always need energy.

Respiration has Two Stages Takes place in the cytoplasm Sugar (glucose) is broken down and only a small amount of energy is released.

Respiration has Two Stages Takes place in the mitochondria. The small molecules are broken down into even smaller molecules. The energy is in chemical form but is easier to use and releases a large amount of energy. This is why the mitochondria is the “powerhouse”

Products of Respiration Carbon dioxide, water, and energy are released during respiration.

The Respiration Equation C6 H12 O6 + 6 O2 6 CO2 + 6 H2O + Energy Sugar (glucose) oxygen Carbon Dioxide Water Besides releasing a lot of energy, cell respiration also produces CO2 and H2O. Both of these products are released when we breathe.

Photosynthesis and Respiration They are the opposite of each other. Photosynthesis uses CO2, Water, and energy to make sugar and oxygen. Respiration uses sugar and oxygen and gives off CO2, water, and energy

Photosynthesis and Respiration Together they form a cycle that keeps levels of oxygen and CO2 about the same in our atmosphere. Plants and animals help to keep each other alive.

Cell Division Chapter 4 Section 3

Stage 1 Interphase The cell grows, makes copies of its DNA and prepares to divide into two cells.

Stage 2 Mitosis The cells nucleus divides into two new nuclei. A copy of DNA is distributed to each daughter cell. What is a daughter cell? Chromatin in the nucleus condenses to form chromosomes

Mitosis Continued At the end of mitosis a new nucleus is formed around each chromosome. The results of mitosis is the creation of two cells identical to the original cell.

Stage 3 Cytokinesis The cytoplasm divides Organelles are distributed to each new cell. When its over there are two new daughter cells and the whole process starts again.

Structure and Replication of DNA DNA replication takes place during interphase Looks like a twisted ladder The rungs are made of four types of nitrogen. Adenine pairs with Thymine (A-T) Guanine pairs with Cytosine (G-C)

Cell Differentiation Chapter 4 Section 4

Cell Differentiation When cells differentiate they become different from one another. They begin to carry out specialized functions. They organize into tissues, organs and organ systems.

How Cells Differentiate The DNA in each cell holds a plan for what type of cell it will be. Certain parts of DNA are turned off, DNA still actively guides how the cell develops.

How Cells Differentiate cont. Once the cell’s future has been determined, when and how much it changes depends on its DNA, its function and the type of organism.