Question

8.3 cell transport hs - ls1 - 2, hs - ls1 - 3

1. the relatively constant internal physical and chemical conditions that all organisms must maintain to survive is known as

a. osmosis. c. homeostasis.
b. endocytosis. d. exocytosis.

1. solute particles move from an area of higher concentration to an area of lower concentration in a process called

a. osmosis. c. diffusion.
b. transport. d. equilibrium.

1. large molecules such as glucose move across cell membranes through special protein channels during

a. active transport.
b. facilitated diffusion.
c. osmosis.
d. bulk transport.

1. what is the term that describes the diffusion of water through a selectively permeable membrane?
2. explain why cells are almost always hypertonic to fresh water.
3. what is the main difference between passive transport and active transport of materials across a cell membrane?
4. what are the two types of active transport, and how do they differ?

8.4 homeostasis and cells hs - ls1 - 2, hs - ls1 - 3

1. which type of organism consists of specialized cells?

a. unicellular prokaryotes
b. multicellular prokaryotes
c. unicellular eukaryotes
d. multicellular eukaryotes

1. all unicellular organisms

a. are prokaryotes.
b. are bacteria.
c. reproduce.
d. have a nucleus.

1. in what way does specialization of cells contribute to maintaining homeostasis in multicellular organisms?
2. describe the levels of organization in a multicellular organism.
3. in general, how do cells in a multicellular organism communicate?

critical thinking hs - ls1 - 1, hs - ls1 - 2, hs - ls1 - 3

1. evaluate models cells are often compared to factories. how is a factory a useful model for explaining the cell?
2. evaluate reasoning a student is asked to classify examples of cells based on prepared microscope slides. the student classifies the cells according to their most prominent color. evaluate the students classification scheme.
3. construct an explanation in a multicellular organism, the dna in every cell is essentially the same. how does the cell theory help explain this?
4. apply scientific reasoning the beaker shown here has a membrane that separates two solutions. water can pass through the membrane, but starch cannot pass through it. how will the fluid levels change over time? explain your prediction.
5. critique in constructing a model of a plant cell, a student surrounds the model with plastic bricks. the bricks represent the cell wall. how could the model be improved to represent the cell wall more accurately?
6. synthesize information why is intercellular communication essential for a multicellular organism to function properly?
7. infer pacemakers are devices that help keep heart muscles contracting at a steady rate. if a person needs a pacemaker, what does that suggest about his or her heart cells ability to send and receive messages?
8. plan an investigation you want to know how temperature affects the rate of diffusion. describe an investigation that would provide evidence to support a conclusion. include simple materials such as water and food coloring.

Explanation:

1. Homeostasis is the maintenance of relatively constant internal physical and chemical conditions in organisms.
2. Diffusion is the movement of solute particles from high - to low - concentration areas.
3. Facilitated diffusion is the movement of large molecules like glucose across cell membranes through special protein channels.
4. Osmosis is the diffusion of water through a selectively permeable membrane.
5. Cells are often hypertonic to fresh water because they have more solutes inside.
6. Passive transport doesn't require energy and moves substances along a concentration gradient, while active transport requires energy and moves substances against a concentration gradient.
7. The two types of active transport are primary (uses ATP directly) and secondary (uses energy from an electrochemical gradient).
8. Multicellular eukaryotes consist of specialized cells.
9. All unicellular organisms reproduce.
10. Specialized cells contribute to homeostasis by performing specific functions.
11. The levels of organization in a multicellular organism are cells, tissues, organs, and organ systems.
12. Cells in a multicellular organism communicate through chemical signals, gap junctions, etc.
13. A factory is a useful model for a cell as different departments in a factory are like organelles with specific functions in a cell.
14. Classifying cells by color is not a valid classification scheme as color is not a fundamental characteristic for cell classification; cell type should be based on structure, function, or genetic makeup.
15. The cell theory states that all cells come from pre - existing cells. In a multicellular organism, all cells are derived from a single zygote, so the DNA is essentially the same.
16. Water will move from side B (dilute starch solution) to side A (concentrated starch solution) by osmosis, causing the fluid level on side A to rise and on side B to fall.
17. To more accurately represent the cell wall, the plastic bricks could be made more porous to represent the semi - permeable nature of the cell wall.
18. Intercellular communication is essential for multicellular organisms as it coordinates activities like growth, development, and response to stimuli.
19. If a person needs a pacemaker, it suggests that the heart cells' ability to send and receive messages to maintain a regular heartbeat is impaired.
20. To investigate the effect of temperature on diffusion rate, fill three beakers with water at different temperatures (cold, room - temperature, hot). Add a drop of food coloring to each beaker and observe how quickly the color spreads. The warmer the water, the faster the diffusion rate is expected due to increased molecular motion.

Answer:

1. c. homeostasis
2. c. diffusion
3. b. facilitated diffusion
4. a. osmosis
5. Cells have more solutes inside compared to fresh water.
6. Passive transport doesn't require energy and moves substances along a concentration gradient; active transport requires energy and moves substances against a concentration gradient.
7. Primary (uses ATP directly) and secondary (uses energy from an electrochemical gradient).
8. d. multicellular eukaryotes
9. c. reproduce
10. Specialized cells perform specific functions to maintain homeostasis.
11. Cells, tissues, organs, and organ systems.
12. Through chemical signals, gap junctions, etc.
13. Different departments in a factory are like organelles with specific functions in a cell.
14. Classifying cells by color is not valid as color is not a fundamental characteristic for cell classification; should be based on structure, function, or genetic makeup.
15. All cells come from pre - existing cells, and in a multicellular organism, all cells are derived from a single zygote.
16. Water will move from side B to side A by osmosis, causing the fluid level on side A to rise and on side B to fall.
17. Make the plastic bricks more porous to represent the semi - permeable nature of the cell wall.
18. It coordinates activities like growth, development, and response to stimuli.
19. The heart cells' ability to send and receive messages to maintain a regular heartbeat is impaired.
20. Fill three beakers with water at different temperatures (cold, room - temperature, hot). Add a drop of food coloring to each beaker and observe how quickly the color spreads. The warmer the water, the faster the diffusion rate due to increased molecular motion.