Cell Structure

Question 1

What is the smallest unit that carries out the characteristic functions of life?

Answer 1

the cell

Question 2

What are the two internal elements of the cell?

Answer 2

nucleus and cytoplasm

Question 3

What are the two parts of the cell’s cytoplasm?

Answer 3

1) formed, insoluble elements like organelles
2) cytosol, or the aqueous phase and dissolved molecules

Question 4

What are the boundaries that define compartments and regulate the flow of molecules?

Answer 4

membranes

Question 5

What is the basic framework of a membrane? What are other components included in the framework?

Answer 5

phospholipid bilayer

cholesterol
glycolipids
sphingomyelin

Question 6

What are membrane proteins and what are their functions?

Answer 6

proteins embedded or associated with the phospholipid bilayer

ion channels, ion pumps, hormone receptors (transmembrane proteins)

Question 7

When cut in cross section and viewed with a transmission electron microscope, what is the characteristic structure of a membrane? What composes the structure?

Answer 7

trilaminar (three-layered)

two electron dense lines border with a less dense central zone

Question 8

When cut in cross section and viewed with a transmission electron microscope, what is the characteristic structure of an epithelial membrane? What composes the structure?

Answer 8

multiple layers of different cell types

-epithelial cells
-basal lamia
-reticular lamina (lamia fibroreticularis)

Question 9

What are the components making up the basement mebrane? Which components are translucent? Electron dense?

Answer 9

-lamina densa (central and electron dense)
-lamina lucida (top and translucent)

lamina fibroreticularis (bottom and translucent)

Question 10

What is a glycocalyx?

Answer 10

when a membrane has abundant chains of sugars attached to membrane proteins, and these sugars can be seen microscopically

Question 11

Where are proteins synthesized? What are proteins composed of?

Answer 11

ribosomes

amino acid sequences translated from mRNA

Question 12

What are ribosomes composed of?

Answer 12

ribosomal RNA (rRNA) and proteins

Question 13

What are heterochromatin?

Answer 13

condensed DNA and proteins in the interphase nucleus

Question 14

What are euchromatin?

Answer 14

dispersed DNA and proteins in the interphase nucleus

Question 15

Where is the site of synthesis of most rRNA?

Answer 15

the nucleolus

Question 16

What differentiates rough endoplasmic reticulum from smooth endoplasmic reticulum?

Answer 16

rough endoplasmic reticulum has ribosomes attached to the membrane, smooth has no attachments

Question 17

What happens to proteins synthesized on the rough ER? What gets added to the proteins to synthesize them?

Answer 17

packaged into granules and/or exported out of the cell

peptides that passed into the lumen of the ER and sugars to create glycoproteins

Question 18

How do secretory granules release their contents?

Answer 18

exocytosis

membrane of the granule fuses with the plasma membrane and releases contents into the extracellular space

Question 19

What is the term for membrane-bound organelles that that contain hydrolytic enzymes with acid pH optima? What do they do?

Answer 19

lysosomes

degrade large molecules to smaller ones

Question 20

How are extracellular molecules brought into contact with target molecules? Intracellular?

Answer 20

endocytosis

autophagy

Question 21

Lysosomes that have not been fused to molecules via membrane attachment are termed…

Answer 21

primary

Question 22

Lysosomes that have been fused to molecules via membrane attachment are termed…

Answer 22

secondary

Question 23

Which type of endoplasmic reticulum is active in protein synthesis?

Answer 23

rough ER

Question 24

What are the functions of smooth ER?

Answer 24

phospholipid, cholesterol synthesis, detoxification of drugs, and secrete steroids

Question 25

Mitochondrion is the site of ____ synthesis by...

Answer 25

ATP oxidative phosphorylation

Question 26

Where are mitochondria most numerous at?

Answer 26

sites that require much ATP, like striated muscles

Question 27

Energy is stored in the form of _______ and _______.

Answer 27

glycogen lipids

Question 28

What are polymers of repeating protein subunits?

Answer 28

cytoskeletal elements -microtubules -microfilaments -intermediate filaments

Question 29

What are the main components of microtubules? What is it's main function?

Answer 29

-composed of protein tubulin -25nm diameter, hollow tubes associated with motility and to maintain asymmetric structure

Question 30

What are the main components of microfilaments? What is it's main function?

Answer 30

-polymers of protein actin -7nm diameter participate in generation of motion and structure

Question 31

What are the main components of intermediate filaments? What is it's main function?

Answer 31

-vary in protein composition. type of protein can be used to identify cell -about 10nm diameter form stable intracellular networks with junctions