Unit 3: The Cell

Question 1

provides a barrier between the interior and exterior of the cell and it regulates the flow of substances in and out of the cell.

Answer 1

cell membrane

Question 2

Protective layer for prokaryotes, made of peptidoglycan.

Answer 2

cell wall

Question 3

In a plant cell. Capture energy from the sun and use that energy to build sugar molecules.

Answer 3

chloroplast

Question 4

a short, microscopic, hairlike vibrating structure. Occurs in large numbers on the surface of certain cells.

Answer 4

cilia

Question 5

the fluid that occupies the space inside the cell. the space in which the chemical reactions that enable life take place.

Answer 5

cytoplasm

Question 6

formed by a series of protein filaments, and is both a scaffold for the cell structure and a framework for many cellular activities, including movement and cell division.

Answer 6

cytoskeleton

Question 7

a series of sacs and tubes. put together or assemble the proteins and other cellular components.

Answer 7

endoplasmic reticulum (ER)

Question 8

any of the single-celled or multicellular organisms whose cell contains a distinct, membrane-bound nucleus.

Answer 8

Eukaryotes

Question 9

External appendage to a prokaryote.

Answer 9

flagella

Question 10

Where the proteins assembled in the ER are delivered to different parts of the cell, or in multicellular organisms, to different parts of the body.

Answer 10

golgi apparatus

Question 11

takes fuel in the form of sugar (glucose) and convert it to usable energy ATP.

POWERHOUSE OF THE CELL

Answer 11

mitochondria

Question 12

Region in a prokaryote, where the DNA molecule is present. Does not have a surrounding membrane.

Answer 12

nucleoid region

Question 13

Center of the atom. Contains equal number of protons and neutrons.

Answer 13

nucleus

Question 14

small, simple, single-cell organisms; bacteria are the most prevalent kind. Do not contain a nucleus or any other organelle.

Answer 14

prokaryotes

Question 15

the molecular machines that use the instructions contained in the DNA to build all the proteins needed by the cell.

Answer 15

ribosome

Question 16

specialized mainly for storage. Their membranes do not fuse with the membranes of other cellular components.

Answer 16

vacuole

Question 17

specialized for transport and some other functions. Their membranes can fuse with the plasma membrane, allowing them to empty their contents into the extracellular space. Also may fuse with the membranes of the endoplasmic reticulum and Golgi apparatus, allowing them to empty their contents into those organelles.

Answer 17

vesicle

Question 18

the fabric of the membrane. The structure causes the membrane to be semipermeable. The hydrophobic core blocks the diffusion of hydrophilic ions and polar molecules. Small hydrophobic molecules and gases, which can dissolve in the membrane’s core, cross it with ease.

Answer 18

phospholipid bilayer

Question 19

The cell membrane provides a semipermeable barrier between the inside and the outside of the cell. The phospholipid bilayer structure of the membrane allows selected ions and organic molecules to pass through the plasma membrane and regulates the movement of molecular substances.

Answer 19

selectively permeable

Question 20

moving molecules against their concentration gradient. This is a non- spontaneous process and requires the cell to do work to move the ions “uphill” against the concentration gradient. To do work, the cell must expend energy and actively move (pump) the ions.

Answer 20

active transport

Question 21

material is engulfed within an infolding of the plasma membrane and then brought into the cell within a cytoplasmic vesicle.

Answer 21

endocytosis

Question 22

an internal vesicle fuses with the plasma membrane and releases its contents to the outside.

Answer 22

exocytosis

Question 23

The process of moving impermeable molecules across a membrane (down their concentration gradients) using channels or pores is referred to as _____ ________.

Answer 23

facilitated diffusion

Question 24

homeostasis

Answer 24

The ability or tendency of organisms and cells to maintain stable internal conditions.

Question 25

a process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one, thus equalizing the concentrations on each side of the membrane.

Answer 25

osmosis

Question 26

both large and small molecules spontaneously move from areas of high concentration to areas of low concentration following random movements, referred to as Brownian motion.

Answer 26

simple diffusion