Organelles and Transport

Question 1

What is the nucleus?

Answer 1

contains the cell’s DNA, and coordinates cell activities such as protein synthesis & reproduction
-note: in prokaryotes, nucleoid contains genetic material)

Question 2

What is the nucleolus?

Answer 2

site of ribosome (rRNA) synthesis

Question 3

What is the cytoplasm?

Answer 3

the fluid-filled area in which the cell’s metabolic activities occur; also includes the organelles

Question 4

What is the mitochondria?

Answer 4

double layered, makes ATP, site of fatty acid catabolism; has own circular DNA and ribosomes

Question 5

What are ribosomes?

Answer 5

made of rRNA; makes proteins

Question 6

What is rough ER?

Answer 6

has ribosomes attached to the structure; functions to synthesize and store proteins

Question 7

What is smooth ER?

Answer 7

functions to synthesize lipids and steroid hormones for export

Question 8

What is golgi?

Answer 8

modifies and packages proteins (i.e., glycosylate polypeptides)

Question 9

What are lysosomes?

Answer 9

made by golgi; functions in apoptosis, and break down of nutrients, bacteria, & cell debris

Question 10

What are peroxisomes?

Answer 10

common in the liver & kidney that function to breakdown substances

Question 11

What is the cytoskeleton?

Answer 11

maintain cell shape & movement

Question 12

What are microtubules?

Answer 12

composed of tubulin; support cell & mobility for cell activities

Question 13

What are centriolies, cilia, and flagella?

Answer 13

centrioles: development of spindle fibers for cell division
cilia: short hair like extensions from cell for movement
flagella: thread-like extension from cell for movement

Question 14

What are intermediate filaments?

Answer 14

maintain cell shape

Question 15

What are microfilaments?

Answer 15

composed of actin; used for cell motility

Question 16

What are vacuoles?

Answer 16

vesicles inside cell that move materials & membrane bound

Question 17

What is the extracellular matrix?

Answer 17

function to provide mechanical support & helps bind adjacent cells (most abundant = collagen)

Question 18

What is found in plants?

Answer 18

cell walls: provide support
plastids: a variety of organelles serving various metabolic activities such as chloroplasts for photosynthesis

Question 19

What are some traits of prokaryotes?

Answer 19

1. no nucleus
2. single, circular, naked, double-stranded DNA
3. ribosomes (50S + 30S = 70S)
4. cell walls (peptidoglycan); archaea (polysaccharides)- many have sticky capsules on the cell wall
5. flagella are constructed from flagellin, not microtubules

Question 20

What is the phospholipid membrane permeability?

Answer 20

allows small, uncharged, hydrophobic molecules to freely pass the membrane. Other molecules that are large, polar, or charged require a transporter

Question 21

What does cholesterol do in the cell membrane?

Answer 21

regulates fluidity of cell membrane (↑ temp = ↓ fluidity)

Question 22

What is passive transport?

Answer 22

-no ATP (down gradient)
-includes simple diffusion, osmosis, dialysis, plasmolysis, facilitated diffusion, and countercurrent exchange

Question 23

What is a channel protein?

Answer 23

passage through the membrane for hydrophilic (water soluble), polar, and charged substances

Question 24

What are ion channels?

Answer 24

voltage-ligand, or mechanically gated

Question 25

What are porins?

Answer 25

less specific; pass ions and polar molecules

Question 26

What are carrier proteins?

Answer 26

changes shape after binding to a specific molecule that enables it to be passed across

Question 27

What are transport proteins?

Answer 27

proteins that can use ATP to transport materials across the membrane; includes active transport (e.g., sodium-potassium pump) and facilitated diffusion

Question 28

What is active transport?

Answer 28

-uses ATP (against gradient) -solutes like small ions, amino acids, monosaccharides

Question 29

What is phagocytosis?

Answer 29

plasma membrane invaginates around undissolved material (solid), like bacteria

Question 30

What is pinocytosis?

Answer 30

plasma membrane invaginates around dissolved material (liquid)

Question 31

What is receptor-mediated endocytosis?

Answer 31

form of pinocytosis in which specific molecules called ligands bind to receptors

Question 32

What is hypertonic?

Answer 32

higher solute concentration (shriveled cell)

Question 33

What is hypotonic?

Answer 33

lower solute concentration (swell up/lysed)

Question 34

What is isotonic?

Answer 34

equal solute concentration

Question 35

What is anchoring junction?

Answer 35

includes desmosomes; connects 2 cells together

Question 36

What is tight junction?

Answer 36

encircles each cell, producing a seal that prevents the passage of materials between cells; is characteristic of cells lining the digestive tract

Question 37

What is a gap junction?

Answer 37

narrow tunnels between animal cells; allow passage of ions and small molecules