A bag made of a selectively permeable membrane that only allows water molecules
ID: 96769 • Letter: A
Question
A bag made of a selectively permeable membrane that only allows water molecules through its pores was filled with a 30% sucrose solution and sealed. The bag was placed in a beaker containing pure (100) water. After 20 minutes, what would be the condition of the bag? Select one: of a. The bag would swell b. The bag would shrink C. The bag would remain unchanged d. The sucrose would leave the bag e. There is no way to predict what would happen to the bag with this information Cells are considered the basic unit of all living organisms. What does this statement imply about cells? Select one: a. cells must respond to stimuli b. cells must grow and reproduce c. cells must acquire nutrients and energy from their surroundings d. cells must die e. all of the above Consider the structure of cell membranes. Which part of the membrane is the fluid portion? Select on: of a. Carbohydrates b. Proteins c. DNA d. Phospholipids e. The membrane is not fluid but instead solid Herbicides contain high concentrations of salt. Which statement most accurately explains the effect of herbicides on plants? Select one: of a. Causes water to move into plant cells and rupture them b. Causes water to move out of plant cells and dehydrates them c. Creates a hypertonic environment inside the cells of the plant d. Disrupts plants' nervous system In lab you demonstrated a form of passive transport called osmosis when you placed a stick of celery in regular tap water, Recall how the celery became more crisp or firm after sitting in tap water for the duration of the lab. Based on these results, which solution was hypertonic? Select one: of a. The cells in the celery b. The tap water outside the celery c. Neither-they were both isotonic d. The air surrounding the beaker e. B and D.Explanation / Answer
Answer to Question1:
Selectively permeable membrane is the membrane that allows selective molecules or ions to pass through it by active transport or passive transport.
In the above given condition, osmosis takes place. Osmosis is the movement of water through selectively permeable membrane from higher water concentration to the lower water concentration region, that is down the concentration gradient.
When a selectively permeable membrane separates two solutions, water moves in both directions. But more warer migrates from higher water concentration region than the other. pure water has highest water concentration than 30% sucrose solution. Thus water migrates from beaker into the bag containing 30% sucrose. As a consequence, the bag would swell.
Hence the answer is a.
Answer to Question2:
Cells are called basic units of life. It may be an unicellular organism or a multicellular organism, cell is the smallest unit of the living organism. Cells are the building blocks of an organism.
The basic needs for survival of any living organism are same. The living organism must respond to the stimuli. They must respire, acquire nutrients and energy from the surroundings, metabolise, grow and die. Cells are capable of performing all the above functions of the body and hence they are considered as the basic structural and functional units of life.
Hence the answer is d.
Answer to Question 3:
Fluid mosaic model describes the structure of plasma membrane. Plasma membrane has a phospho lipid fluid structure with in which proteins are arranged in a mosaic pattern. Carbohydrates are attached to both lipids and proteins. The carbohydrates attached to lipids are called glycolipids and those attached to proteins form glycoproteins.
Plasma membrane is composed of carbohydrates, proteins and phospho lipids out of which phospho lipid portion is considered as the fliud portion of membrane.
Hence the answer is d.
Answer to Question 4:
Herbicides are the chemicals used to kill the unwanted plants in the crop. Herbicides contain high concentration of salts. Salt works on herbs by dehydrating plants and disrupting the internal water balance of plants. It causes water to move out of plant cells and dehydrates them.
Hence the answer is b.
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