A cell is a complex system. Like most systems, a cell contains a boundary that separates things that are inside the system from those that are outside of the system. Which part of the cell functions as a system boundary?
Responses
A cytoplasmcytoplasm
B membranemembrane
C nucleusnucleus
D ribosome
B membrane
Nutrients enter a cell ______ the concentration gradient by the process of _______.
Responses
A with; diffusionwith; diffusion
B against; osmosisagainst; osmosis
C against; diffusionagainst; diffusion
D with; endocytosis
A with; diffusion
Describe the movement of molecules in the illustration.
Responses
A Molecules are moving from a lower concentration to a higher concentration.Molecules are moving from a lower concentration to a higher concentration.
B Molecules are moving from a higher concentration to a lower concentration.Molecules are moving from a higher concentration to a lower concentration.
C Molecules are moving from a higher concentration to a lower concentration and then from a lower to higher concentration.Molecules are moving from a higher concentration to a lower concentration and then from a lower to higher concentration.
D Molecules are moving from a lower concentration to a higher concentration and then from a higher concentration to a lower concentration.
B Molecules are moving from a higher concentration to a lower concentration.
To study osmosis, a student placed a thin potato slice in a salt solution. The slice became soft and shriveled. Then, he placed the shriveled slice in water. The slice regained its original shape. Based on the observations, which of these statements is correct?
Responses
A The slice regained its shape because salt moved into the potato.The slice regained its shape because salt moved into the potato.
B The potato slice shriveled because water moved from the salt solution into the slice.The potato slice shriveled because water moved from the salt solution into the slice.
C The potato slice shriveled because water moved out of the slice into the salt solution.The potato slice shriveled because water moved out of the slice into the salt solution.
D The slice regained its shape because the concentration of salt inside and outside the slice became equal.The slice regained its shape because the concentration of salt inside and outside the slice became equal.
C The potato slice shriveled because water moved out of the slice into the salt solution.
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Question
Egg Osmosis
Solution (to remove shell) Egg mass (g) Initial Egg mass (g) after 24 hrs Student Observations
Vinegar (Egg 1) 45 85 Shell gone; egg seemed swollen and larger
Vinegar (Egg 2) 45 85 Shell gone; egg seemed swollen and larger
Vinegar (Egg 3) 45 85 Shell gone; egg seemed swollen and larger
Experimental Solution Egg mass (g) Initial Egg mass (g) after 24 hrs Student Observations
10% Salt Water Solution (Egg 1) 85 85 No change in egg appearance or size
Kayro Syrup (Egg 2) 85 31 Egg was wrinkled and shriveled; much smaller
Distilled Water (Egg 3) 85 105 Egg was larger in size; swollen and tight
Introduction: Students performed an experiment using eggs to observe the effect of osmosis on cells. The egg represented a typical cell. Before beginning the experiment, students soaked the raw eggs overnight in vinegar to remove the shells. What they had in hand, then, was actually a raw, shell-less egg.
Procedure: Day 1 – Students found the mass in grams of their shelled eggs, recording the mass in the data table. The eggs were placed in a beaker and covered with 200 mL vinegar to remove the shells.
Day 2 – The eggs were removed from the vinegar. Visual observations were recorded. The shell-less eggs were wiped dry, massed, and the mass was recorded in the data table. The eggs were placed in a clean beaker and covered with a 10% saltwater solution.
Day 3 – The eggs were removed from the saltwater and visual observations were made and recorded. The eggs were wiped dry , massed, and the mass was recorded. The eggs were placed in a clean beaker and covered with sugar (Kayro) syrup.
Day 4 – The eggs were removed from the syrup and visual observations were made and recorded. The eggs were carefully wiped with a damp cloth, massed, and the mass was recorded. The eggs were placed in a clean beaker and covered with colored (red, green, or blue) distilled water.
Day 5 – The eggs were removed from the water and visual observations were made and recorded. The eggs were dried, massed, and the mass was recorded. Students organized their data and made a bar graph comparing how the solutions affected their egg's (cell’s) mass. Data: One student group’s data is recorded here.
Based on the data in the table, the students can conclude that which substance is hypertonic?
Responses
A vinegarvinegar
B salt watersalt water
C Kayro syrupKayro syrup
D distilled water
B salt water
Plant and animal cells differ in a variety of ways. Notice when you compare the model cells, plant cells contain chloroplasts and animal cells do not. What is the function of this organelle found in plant cells?
Responses
A It is the site of photosynthesis, where glucose is produced.It is the site of photosynthesis, where glucose is produced.
B It is the site of cellular respiration, where cellular energy is produced.It is the site of cellular respiration, where cellular energy is produced.
C It is the site of cellular digestion; glucose is broken down to produce energy.It is the site of cellular digestion; glucose is broken down to produce energy.
D It is the site of protein synthesis; amino acids are joined together to make proteins.