Notes: Cells, Levels of Organization &Photosynthesis

1. Notes: Cells, Levels of Organization &Photosynthesis • TEK Sci.6.10B, Sci.6.10C and Sci.7.8B

2. Cells • Cells are the basic unit of structure and function in all living things. Living things can also be called organisms. • Structure is how something looks. Function is the job that it performs.

3. The Microscope and Cell Theory • The invention of the microscope made it possible for people to discover and learn about cells. • A microscope is an instrument that makes small objects look larger. • Magnification can be adjusted on a microscope to make an object on a microscope appear larger. Resolution can be adjusted on a microscope to make an object appear more clear. • The cell theory is an explanation of the relationship between cells and living things.

4. What is the Cell Theory? • Again the cell theory explains how cells are related to organisms. The three parts of the cell theory are: • 1. All living things are composed of cells. • 2. Cells are the basic unit of structure and function in living things • 3. All cells are produced from other cells.

5. The Cell and its Parts-the Nucleus • The cell is a system, and they contain tiny structures inside of them called organelles. Organelles carry out specific function within the cell. • The nucleus acts as the “brain of the cell”. It is the cell’s control center and directs all of the cells activities. The nucleus contains the genetic material called chromosomes.

6. The Cell and its Parts-Cytoplasm and Mitochondria • The cytoplasm is a clear, thick, gel-like fluid found inside of the cell. The nucleus and other cell organelles are held in place by the cytoplasm. • The mitochondria is a rod-shaped organelle called the “powerhouse” of the cell. It is called the powerhouse of the cell because it produces most of the energy the cell needs to carry out its functions.

7. The Cell and its Parts-Vacuole and Endoplasmic Reticulum • A vacuole is a storage sac within the cell which stores water, food, waste products and other materials. Plant cells will have larger vacuoles than animal cells. • The endoplasmic reticulum is a network of passageways inside of the cell which carries materials from one part of the cell to another

8. The Cell and its Parts-Golgi Bodies, Ribosomes and Lysosomes • Golgi bodies receive materials from the endoplasmic reticulum and send them to other parts of the cell. They also release materials outside the cell. • Ribosomes can be attached to the endoplasmic reticulum or float free within the cytoplasm. Ribosomes produce proteins which travel along the e.r. • Lysosomes are very small organelles which contain chemicals that break down food particles and worn out cell parts.

9. The Cell and its Parts- Chloroplasts • Chloroplasts are only found in plant cells and some bacteria. They are a large green structure giving all plant cells a green color. • Chloroplasts capture radiant energy from sunlight and use it to produce glucose (a simple sugar) and oxygen in a process called photosynthesis.

10. The Cell and its Part-Cell Membrane and Cell Wall • The cell membrane protects the cell and regulates what substances enter and leave the cell. • The cell wall is only located in plant and some bacteria cells. The cell wall is stiff and surrounds the cell membrane-giving plant cells a rigid boxlike shape.

11. Structure and Function in Cells • Plants, animals and other complex organisms contain many cells. Multicellular organisms are organisms made up of many cells. Unicellular organisms are made up of one cell. • Cells in many complex organisms are specialized-meaning different kinds of cells perform different functions.

12. Examples of Structure and Function in Cells • Many plants have root cells that are specialized to absorb water from soil. • Muscle cells in animals specialize in movement. • Nerve cells have long thread-like projections called dendrites which are specialized to carry chemical messages. • Red blood cells are thin and flexible so that they carry oxygen throughout tiny blood vessels in the body.

13. Levels of Organization • The bodies of many multicellular organisms have five levels of organization-cells, tissues, organs, organ system, organism and population. • A group of cells that perform a specialized function is called a tissue. • The next level of organization is the organ, which is a group of tissues that perform a special function. The stomach, heart, and bones in your body are organs.

14. Levels of Organization • An organ system, such as your digestive, circulatory, and skeletal systems, is a group of organs that perform a complex function. • Every organism interacts with other organisms and the environment in which it lives. A population is all the members of one kind of organism in a particular area.

15. Photosynthesis • The process through which plants and some bacteria make their own energy is called photosynthesis. They use radiant energy from the sun and it is converted into chemical energy. • 6 CO2 + 6H2O + radiant energy C6H12O6 + 6 O2

16. Photosynthesis • The equation reads carbon dioxide and water combine in the presence of radiant energy to produce glucose and oxygen. • CO2 is carbon dioxide. • H2O is water. • C6H12O6 is glucose a simple sugar which is the plants chemical energy. • O2 is oxygen.