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Question 1

What are the principles of the cell theory?

Answer 1

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

Question 2

What are the differences between a prokaryotic cell and a eukaryotic cell?

Answer 2

Eukaryotic cells contain a nucleus and other organelles. Prokaryotic cells are cells without a nucleus or other membrane-bound organelles.

Question 3

What is a cell?

Answer 3

A cell is the basic structural and functional unit of all living organisms.

Question 4

What is cell theory?

Answer 4

The cell theory is one of the fundamental ideas of modern biology.

Question 5

What is a plasma membrane?

Answer 5

A plasma membrane is a special boundary that helps control what enters and leaves the cell.

Question 6

What is an organelle?

Answer 6

Organelles are specialized structures that perform specific cell functions.

Question 7

What is a nucleus?

Answer 7

The nucleus is the distinct central organelle that contains the cell’s genetic material.

Question 8

How does a cell’s plasma membrane function?

Answer 8

The plasma membrane forms a thin, flexible boundary between a cell and its environment.

Question 9

What are the roles of proteins, carbohydrates, and cholesterol in the plasma membrane?

Answer 9

Cholesterol is non-polar; prevents the fatty acid tails of the phospholipid bilayer from sticking together. Cholesterol contributes to the fluidity of the membrane. Carbohydrates define the cell’s characteristics and help cells identify chemical signals.

Question 10

What is selective permeability?

Answer 10

They allow some substances to pass through while keeping others out.

Question 11

What is the phospholipid bilayer?

Answer 11

Two layers of phospholipids are arranged to allow the membrane to exist in a watery environment.

Question 12

What is the fluid mosaic model?

Answer 12

The fluid mosaic model describes the phospholipids in the bilayer as a “sea” in which other components can float and move around.

Question 13

What is the prosses of diffusion?

Answer 13

Diffusion is 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 14

What is the prosses of facilitated diffusion?

Answer 14

Facilitated diffusion uses transport proteins to move ions and small molecules across the plasma membrane. Diffusion and facilitated diffusion are types of passive transport – they require no additional energy.

Question 15

What is the prosses of active transport?

Answer 15

The movement of particles across the cell membrane, against the concentration gradient, requires energy and is called active transport.

Question 16

Define the dynamic equilibrium.

Answer 16

When diffusion occurs over a long enough time, concentrations become uniform, and the solution will reach dynamic equilibrium.

Question 17

Define osmosis.

Answer 17

Osmosis is the diffusion of water across a selectively permeable membrane.

Question 18

An isotonic solution is …

Answer 18

An isotonic solution has the same concentration of water and solutes as the cell’s cytoplasm. Water still moves through the membrane, but it enters and leaves simultaneously.

Question 19

A hypotonic solution is …

Answer 19

A hypotonic solution has a lower concentration of solutes than the cell’s cytoplasm.

Question 20

cytoplasm

Answer 20

The environment enclosed by the plasma membrane is a semifluid material called cytoplasm.

Question 21

cytoskeleton

Answer 21

The cytoskeleton is a supporting network of long, thin protein fibers that form a framework for the cell and proved an anchor for the organelles.

Question 22

ribosome

Answer 22

Ribosomes are organelles that manufacture proteins.

Question 23

endoplasmic reticulum

Answer 23

The endoplasmic reticulum (ER) is a membrane system of folded sacs and interconnected channels that serves as the site for protein and lipid synthesis.

Question 24

Golgi apparatus

Answer 24

The Golgi apparatus is a flattened stack of membranes that modifies, sorts, and packages proteins.

Question 25

vacuole

Answer 25

A vacuole is a membrane bound sac used for temporary storage.

Question 26

lysosome

Answer 26

Lysosomes are vesicles that contain substances that digest excess or worn-out organelles and food particles. They also digest bacteria or viruses that invade the cell.

Question 27

Centrioles

Answer 27

Centrioles are organelles made of groups of microtubules that function during cell division.

Question 28

Mitochondria

Answer 28

Mitochondria convert fuel particles into usable energy.
They have an outer membrane and a highly folded inner membrane that provides surface area for breaking the bonds in sugar molecules.

Question 29

chloroplasts

Answer 29

Plant cells and some other eukaryotes contain chloroplasts, which capture light and convert it into chemical energy in process called photosynthesis.

Question 30

cell wall

Answer 30

a thick, rigid, mesh of fibers that surround the outside of the plasma membrane.

Question 31

Cilia

Answer 31

Cilia are short, numerous projections that look like hair.