Chapter 7 Test

Question 1

Three Principles of Cell Theory

Answer 1

1. All living organisms are composed of one or more cells.
2. Cells are the basic unit of structure and organization of all living organisms.
3. Cells arise only from previously existing cells, cells with passing copies of their genetic material on to their daughter cells.

Question 2

Microscopes

Answer 2

Enlarge images by different magnifications. Reverse and flip the image shown through the microscope.

Question 3

Eukaryotic Cells

Answer 3

Organelles are specialized structures that perform specific cell functions.
Nucleus is the distinct central organelle that contains the cell’s genetic material.
Eukaryotic are much larger than prokaryotic cells.

Question 4

Prokaryotic Cells

Answer 4

Cells without a nucleus or other membrane-bound organelles.
Smaller and simpler compared to Eukaryotes.
Similar to the first organisms that lived on earth.

Question 5

Selective Permeablility

Answer 5

Plasma membranes have selective permeability, meaning they allow some substances to pass through while keeping others out. The plasma membrane controls how, when, and how much of various substances enter and leave a cell.

Question 6

Phospholipid Bilayer

Answer 6

A plasma membrane is composed of this which are two layers of phospholipids that are arranged to allow the membrane to exist in a watery environment.

Question 7

Polar Heads

Answer 7

Face on the outside of the phospholipid bilayer and they are hydrophilic which means they love water.

Question 8

Non-polar tails

Answer 8

Face the inside of the phospholipid bilayer and they are hydrophobic which means they don’t like water.

Question 9

Cholesterol

Answer 9

Prevents the fatty acid tails of the phospholipid bilayer from sticking together.
Contributes to the fluidity of the membrane.

Question 10

Carbohydrates

Answer 10

Define the cell’s characteristics.
Help cells identify chemical signals.

Question 11

Fluid Mosaic Model

Answer 11

Describes the phospholipids in the bilayer as a “sea” in which other components can float and move around.
Different substances in the plasma membrane create a pattern or mosaic on the surface of the cell.

Question 12

Diffusion

Answer 12

Particles in solids, liquids, and gases are in constant random motion.
Defined as the net movement of particles from an area of high concentration to an area of lower concentration.
Additional energy is not required for diffusion because the particles are already in motion.

Question 13

Dynamic Equilibrium

Answer 13

When diffusion occurs over a long enough time, concentrations become uniform.
Molecules still move, but the concentration remains the same.

Question 14

Facilitated Diffusion

Answer 14

Uses transport proteins to move ions and small molecules across the plasma membrane. Requires no additional energy.

Question 15

Osmosis

Answer 15

Diffusion of Water through a selectively permeable membrane.

Question 16

Isotonic Solution

Answer 16

Same concentration of water and solutes as the cytoplasm of the cell. Water moves through the membrane, but it enters and leaves at the same rate.

Question 17

Hypotonic

Answer 17

Has a lower concentration of solutes compared to the cytoplasm. Water moves into the cell. Animal cells can burst in extreme situations.

Question 18

Hypertonic

Answer 18

Higher concentration of solutes compared to the cytoplasm of the cell. Water moves out the cell. Not good for plant or animal cells because then cells shrivel.

Question 19

Turgor pressure

Answer 19

Bacteria and plants have cell walls that prevent them from over-expanding. In plants the pressure exerted on the cell wall is called turgor pressure.

Question 20

Passive Transport

Answer 20

No additional energy needed. Movement of molecules from a high concentration area to a low concentration area.

Question 21

Active Transport

Answer 21

Energy required. Movement of molecules from a low concentration area to a high concentration area.

Question 22

Na+/K+ ATPase Pumps

Answer 22

Found in the plasma membrane of animal cells. Maintain levels of sodium and potassium inside/outside the cell.

Coupled transport allows sugars to pair with Na+ ions and enter the cell through a membrane protein called a coupled channel.

Question 23

Endocytosis

Answer 23

The process by which a cell surrounds an object in the outside in a portion of the plasma membrane.

Question 24

Exocytosis

Answer 24

The excretion of materials at the plasma membrane

Question 25

Phagocytosis

Answer 25

Cell Eating.

Question 26

Pinocytosis

Answer 26

Cell Drinking.

Question 27

Cells

Answer 27

Go to my cell flashcards.