Chapter 5 Exam 2

Question 1

what are the essential features of a cell

Answer 1

can store and transmit info, has a plasma membrane, can harness energy from environment

Question 2

what is a micelle

Answer 2

ball like structure formed by lipids with a bulky hydrophilic head and a single fatty acid tail

Question 3

what is a liposome

Answer 3

closed structure with an inner space, no free edges that would expose lipids to the environment

Question 4

what does the speed of molecules moving within and across a membrane depend on

Answer 4

Temperature and structure of hydrocarbon tails

Question 5

explain saturated vs unsaturated fatty acids

Answer 5

saturated have no double bonds, unsaturated has double bonds

Question 6

what does cholesterol do

Answer 6

increases or decreases the fluidity of membrane depending on temperature

Question 7

what does normal temperatures do to cholesterol

Answer 7

reduces the mobility of phospholipids and fluidity of the membrane

Question 8

what does lower temperatures do to cholesterol

Answer 8

prevents phospholipids from packing tightly increasing fluidity

Question 9

what is carrier mediated diffusion

Answer 9

binding of the transporter molecule inducing a conformational change in the carrier membrane protein, allowing the molecule to be transported across the lipid bilayer

Question 10

what is an antiporter

Answer 10

pump that moves ions in opposite directions

Question 11

what is an example of an antiporter

Answer 11

sodium potassium pump

Question 12

what is a symporter

Answer 12

transporter that moves 2 molecules in same direction

Question 13

what is secondary active transport

Answer 13

using one gradient to drive transport against another

Question 14

what is hypertonic

Answer 14

cell is shrunk because water leaves and sodium is high outside the cell

Question 15

what is hypotonic

Answer 15

cell is swollen because water comes in because sodium is high inside

Question 16

what is a cell wall composed of

Answer 16

polysaccharides

Question 17

what are vacuoles

Answer 17

water filled organelles that contribute to structural rigidity of plants by maintaining turgor pressure against cell walls

Question 18

what are chloroplasts

Answer 18

enable plant cells to harness energy from sunlight to synthesize sugars

Question 19

what makes up the endomembrane system

Answer 19

nuclear envelope, ER, Golgi apparatus, vesicle, lysosome, plasma membraen

Question 20

what are some characteristics of the nuclear membrane

Answer 20

defines boundary of nucleus, inner and outer membranes. contains nuclear pores

Question 21

what molecules require active transport through nuclear pores? passive?

Answer 21

active-large proteins and RNA

passive- small molecules and ions

Question 22

where do proteins made in the cytosol with no signal peptidases go

Answer 22

cytosol

Question 23

where do proteins made in the cytosol with amino terminal signals go

Answer 23

chloroplast or mitochondrion

Question 24

where do proteins made in the cytosol with internal signals go

Answer 24

nucleus by a nuclear localization signal

Question 25

what is the primary site of lipid synthesis

Answer 25

smooth ER

Question 26

what is the primary site of protein synthesis

Answer 26

rough ER

Question 27

what happens in cells that have well developed SER

Answer 27

SER produced cholesterol and contains enzymes that convert cholesterol to steroid hormones

Question 28

where do proteins go from RER

Answer 28

1. within lumen of endomembrane system
2. embedded in RER membrane
3. secreted out of the cell

Question 29

where does the protein go if it is destined for lumen or to be secreted

Answer 29

it is fed into ER lumen as its synthesized by the membrane bound ribosome

Question 30

where does the protein go if it is destined to be embedded in the membrane

Answer 30

it is inserted into membrane as it is synthesized

Question 31

how can polypeptides made in the RER move into lumen or membrane

Answer 31

if amino terminal sequence is present

Question 32

by what mechanism do polypeptides made in the RER move into lumen or membrane

Answer 32

SRP mechanism

Question 33

what is the function of the Golgi apparatus

Answer 33

1. modify proteins and lipids produced in ER
2. sort proteins and lipids to final destination
3. synthesize the cells carbohydrates

Question 34

what do lysosomes do

Answer 34

• vesicles from Golgi that grade damaged or needed macromolecules
• golgi delivers enzymes that break down macromolecules
• proton pumps help maintain acidic pH in a lysosome

Question 35

what do mitochondria do

Answer 35

• harnesses energy for the cell
• were once bacteria captured by the eukaryotic cell
• double membrane
• contains own genome

Question 36

what do chloroplasts do

Answer 36

• harness energy for the cell
• 3 membranes (outer, inner, thylakoid)
• contains own genome