Homeostasis and cell transport
Objectives:
1. Understand and explain the importance of homeostasis
2. Identify the difference between negative and positive feedback loops
3.Distinguish the difference between Passive and Active transport
Essential questions:
1. What is the goal of homeostasis?
2. What is the difference between positive and negative feedback loops?
3. What is the difference between Passive and Active transport?
Key terms:
Concentration Gradient- A gradual difference in concentration of a substance in a solution as a function of distance
Homeostasis- The process of maintaining a stable internal environment
Diffusion- The movement of molecules down a concentration gradient. Moves from high concentration to low concentration
Osmosis-The movement of water from where dissolved substances are less concentrated to more concentrated. Form of passive energy
Passive Transport- The movement of a substance across the plasma membrane without any input of energy
Active Transport- The movement of particles from an area of low concentration across a membrane to an area of high concentration
Facilitated diffusion- A form of transport that involves the molecules passing through a concentration gradient
Osmoregulation-maintenance by an organism of an internal balance between water and dissolved materials
Gas exchange- The delivery of oxygen from the lungs to the bloodstream
Thermoregulation- the regulation of body temperature
Negative feedback loop- when your body works to get back to its original state
Positive feedback loop- Amplifies a change to the system, causing it to move farther and farther from its original state
Hypotonic- Fluid has a lower concentration of dissolved substances than a cell’s interior
Hypertonic- The concentration of solutes is greater outside the cell than inside it
Homeostasis regulates and maintains internal conditions such as temperature, glucose, water, and oxygen. To maintain homeostasis the body relies on a cycle called a negative feedback loop. If any change to a system occurs, a negative feedback loop will cause the system to return to its original state. There is also a positive feedback loop which is the opposite of a negative feedback loop. A positive feedback loop amplifies a change to the system which causes it to move farther and farther from its original state. Negative feedback loops regulate the body’s internal state. The normal body temperature is 37.0 degrees C (98.6 degrees F), so when it moves farther away from this point, changes occur throughout the body so that it can return to its original state. There is constant movement in the plasma membrane as the molecules move back and forth. If there was not movement of the molecules then waste would build up causing needed materials to not be able to enter. Dissolved substances that are more concentrated in one area than another forms a concentration gradient. Any type of cellular transport that does not require energy input is Passive transport. Osmosis is the movement of water from areas of higher water concentration to lower water concentration and it requires no energy input which makes it a form of passive transport. A hypotonic fluid has a lower concentration of dissolved substances than a cell’s interior, an isotonic fluid has an equal concentration of dissolved substances to a cell’s interior, and a hypertonic fluid has a greater concentration of dissolved substances than a cell’s interior. The three types of Passive transport are diffusion, osmosis, and facilitated diffusion. Active transport requires energy in the form of ATP. Ions and molecular pumps are mechanisms of active transport.
Multiple Choice and Open-ended Questions:
1. How does the cell membrane help maintain Homeostasis?
A. Help to absorb glucose from digested food
B. Helps regulate and slow down the flow of water into cells - answer
C. It takes lower energy reactants and changes them into higher energy products
D. Convert biochemical energy from nutrients then release waste products
2. What conditions should your body maintain?
A.Temperature, water, and oxygen
B. Temperature, oxygen, and osmosis
C. Temperature, hypothalamus, and oxygen
D. Temperature, water, glucose, and oxygen
3. What is Osmosis an example of?
A.Active Transport
B. Negative Feedback
C. Passive Transport
D.Positive feedback
1. You are standing outside and the temperature is very cold, so you start to shiver. Explain why you are shivering.
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2. If a scent is sprayed in a room how is it that others are able to smell it too?
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