Ch.7-4 & 8-1 Homeostasis and Cell Energy Cells

POINT > Define homeostasis POINT > Compare homeostasis in unicellular and multicellular organisms POINT > Identify mechanisms of cell communication POINT > Describe ATP structure POINT > Explain how ATP is used by cells

POINT > Define homeostasis Most cells can only survive in a relatively narrow range of physical and chemical conditions Homeostasis is the maintenance of relatively constant internal physical & chemical conditions

POINT > Compare homeostasis in unicellular and multicellular organisms If an organism is unicellular, the single cell must be able to: -Find sources of energy or food -Keep conc. of water & minerals within certain levels -Respond to environment -Grow & reproduce

POINT > Compare homeostasis in unicellular and multicellular organisms In multicellular organisms cells are specialized to perform particular tasks and to communicate with one another Specialized cells cooperate to maintain homeostasis of the organism

Specialized cells are organized Tissues POINT > Compare homeostasis in unicellular and multicellular organisms Specialized cells are organized Tissues

Four types of animal tissues: POINT > Compare homeostasis in unicellular and multicellular organisms Four types of animal tissues: 1. Epithelial tissue: skin, lining of digestive tract and body cavities 2. Connective tissue: fat, bone, blood, cartilage, tendons and ligaments

Four types of animal tissues: POINT > Compare homeostasis in unicellular and multicellular organisms Four types of animal tissues: 3. Muscle tissue 4. Nervous tissue

Specialized cells are organized: Tissues Organs Organ Systems POINT > Compare homeostasis in unicellular and multicellular organisms Specialized cells are organized: Tissues Organs Organ Systems

WB CHECK: Compared to cells in multicellular organisms, unicellular organisms have less homeostasis to worry about have specialized roles in homeostasis must carry out all homeostasis tasks What are four types of animal tissue?

POINT > Identify mechanisms of cell communication In multicellular organisms cells must be able to communicate with each other 1. Cellular junctions hold cells firmly together and allow messages & signals to pass quickly from one cell to another

POINT > Identify mechanisms of cell communication 2. Proteins and cell membrane carbohydrates act as receptors: A receptor is a location that a signal molecule can bind to, and cause a change to cellular activity

POINT > Identify mechanisms of cell communication This process, when a signal on the outside of the cell causes a cellular change, is called signal transduction

POINT > Identify mechanisms of cell communication Receptors and signal transduction allow cells to communicate with other cells that are not nearby

POINT > Identify mechanisms of cell communication

WB CHECK: Cell surface receptors are usually composed of lipids play no part in homeostasis can receive messages from other cells hold cells tightly together How can cells next to each other communicate?

POINT > Describe ATP structure Adenosine tri-phosphate (ATP) ATP is a compound used by cells to release energy

POINT > Describe ATP structure ATP is composed of: Adenine Draw & Label Me!!

POINT > Describe ATP structure ATP is composed of: Ribose Sugar

POINT > Describe ATP structure ATP is composed of: Three phosphate groups

POINT > Explain how ATP is used by cells ATP begins as ADP (Adenosine Diphosphate). A phosphate is added to form ATP Phosphate bonds store energy

POINT > Explain how ATP is used by cells ATP phosphate bonds can break to reform ADP Breaking phosphate bonds releases energy

Break phosphate bonds to release energy ATP Energy stored by forming phosphate bonds ADP

WB CHECK: The energy in ATP is stored in the phosphate bonds in the ribose sugar in the adenine in the nucleus Which has more energy, ADP or ATP?

POINT > Explain how ATP is used by cells ATP is used for: 1. Active transport Ex. Sodium-Potassium (Na-K) pumps move Na+ out of cell and K+ into cell 2. Muscle contraction 3. Creating motion with flagella & cilia

POINT > Explain how ATP is used by cells ATP is used for: 4. Making proteins 5. Responding to chemical signals at surface 6. Allows nerve cells to communicate with each other

WB CHECK: What are two things ATP is used for in cells? What are the three parts of an ATP molecule?

POINT > Explain how ATP is used by cells Cells use ATP very rapidly to drive energy-requiring processes A human uses about their body weight in ATP every day! Yet…. Human body has only about 250g of ATP at any time Each ATP is recycled 500-750x/day (ATP ↔ADP)

Homework: Read pages 214-217, 226-228 Assess page 217 #1-2 Assess page 228 #1-2 Workbook pages 127-8