UNIT 3 bio review

Question 1

Term: Diffusion

Answer 1

Definition: The movement of molecules from an area of higher concentration to an area of lower concentration.

Question 2

Term: Selectively permeable

Answer 2

Definition: A property of cell membranes that allows some substances to pass through while blocking others.

Question 3

Term: Indicators

Answer 3

Definition: Substances that change color or properties in the presence of specific chemicals, used to test for their presence.

Question 4

Term: Dialysis tubing

Answer 4

Definition: A synthetic, semi-permeable membrane used in experiments to model the cell membrane.

Question 5

Term: Starch

Answer 5

Definition: A large carbohydrate molecule that is too big to pass through a selectively permeable membrane.

Question 6

Term: Glucose

Answer 6

Definition: A small, simple sugar molecule that can pass through a selectively permeable membrane.

Question 7

Term: Starch indicator

Answer 7

Definition: Iodine solution, which turns blue-black in the presence of starch.

Question 8

Term: Glucose indicator

Answer 8

Definition: Benedict’s solution, which changes color (e.g., orange) when heated in the presence of glucose.

Question 9

Term: Controls

Answer 9

Definition: Experimental setups that remain constant to ensure reliable comparisons.

Question 10

Term: Cytoplasm

Answer 10

Definition: The jelly-like substance inside cells where organelles are suspended and metabolic reactions occur.

Question 11

Term: Cell membrane

Answer 11

Definition: The thin, flexible barrier that surrounds the cell, controlling the entry and exit of substances.

Question 12

Term: Cell wall

Answer 12

Definition: A rigid outer layer in plant cells, providing structure and protection.

Question 13

Term: Osmosis

Answer 13

Definition: The movement of water molecules through a selectively permeable membrane from an area of low solute concentration to high solute concentration.

Question 14

Term: Wet mount

Answer 14

Definition: A slide preparation technique in which a sample is placed in a drop of liquid on a slide and covered with a cover slip.

Question 15

Term: Cover slip

Answer 15

Definition: A thin, flat piece of transparent material placed over a specimen on a microscope slide.

Question 16

Question: What does hydrophobic mean?

Answer 16

Answer: Water-repelling; refers to the tails of phospholipids in the cell membrane.

Question 17

Question: What does hydrophilic mean?

Answer 17

Answer: Water-attracting; refers to the heads of phospholipids in the cell membrane.

Question 18

Question: What are the functions of the cell membrane?

Answer 18

Answer: Protects the cell, controls the movement of substances in and out, and supports communication between cells.

Question 19

Term: Passive transport

Answer 19

Definition: The movement of substances across the cell membrane without using energy.

Question 20

Term: Facilitated diffusion

Answer 20

Definition: Passive transport of molecules across a membrane through protein channels.

Question 21

Term: Hypotonic

Answer 21

Definition: A solution with a lower solute concentration compared to another solution, leading to water entering the cell.

Question 22

Term: Hypertonic

Answer 22

Definition: A solution with a higher solute concentration compared to another solution, leading to water leaving the cell.

Question 23

Term: Isotonic

Answer 23

Definition: A solution with equal solute concentration compared to another solution, resulting in no net water movement.

Question 24

Term: Active transport

Answer 24

Definition: The movement of substances against a concentration gradient, requiring energy (ATP).

Question 25

Term: Endocytosis

Answer 25

Definition: The process by which cells engulf substances into vesicles to bring them into the cell.

Question 26

Term: Exocytosis

Answer 26

Definition: The process of vesicles fusing with the cell membrane to release substances outside the cell.

Question 27

Question: Explain the Diffusion Through a Membrane lab.

Answer 27

Answer: The lab demonstrates diffusion and osmosis using dialysis tubing. Glucose and iodine can pass through the membrane, while starch cannot.

Question 28

Question: What is the role of starch and glucose indicators?

Answer 28

Answer: Starch indicator (iodine) detects starch by turning blue-black; glucose indicator (Benedict's solution) detects glucose by turning orange when heated.

Question 29

Question: How do you prepare a wet mount?

Answer 29

Answer: Place the sample on a slide, add a drop of water, and carefully place a cover slip at an angle to avoid air bubbles.

Question 30

Question: What happens to glucose and starch in the lab setup?

Answer 30

Answer: Glucose moves out of the tubing into the surrounding solution; starch remains inside because it is too large to pass through.

Question 31

Question: What happens to a plant cell in salt water?

Answer 31

Answer: The cell shrinks as water leaves due to osmosis, and the membrane pulls away from the cell wall (plasmolysis).

Question 32

Question: What happens to a plant cell in pure water?

Answer 32

Answer: The cell swells as water enters by osmosis, but the cell wall prevents it from bursting.