5 - Lipids, Membranes & Cells

Question 0

Which form of energy would a bird use? and why

Answer 0

lipids because storage is tight and it doesn’t attract water therefore lighter

Question 1

What has greater surface tension - water or oil?

Answer 1

Water

Question 2

To create a fate what kinds of reaction must happen?

Answer 2

a dehydration reaction

Question 3

are triglicerides polar or non polar?

Answer 3

no polar

Question 4

The head of a fatty acid has which type of group at the head?

Answer 4

coarboxyl

Question 5

What kind of head is on a steroid?

Answer 5

4 ring structure at top of the isoprene chain

hydrophillic

Question 6

What does amphipathic mean?

Answer 6

has both hydrophobic & hydrophilic elements

“dual sympathy”

Question 7

How do lipids behave in water?

Answer 7

the form micelles
have short acid tails
or
crate phospholipid bi layers

Question 8

What is the distinguishing factor between a saturated and unsaturated fat?

Answer 8

double bonds in unsaturated

single bond in saturated

Question 9

Describe diffusion

Answer 9

the movement at random

from a place of high concentration to a low concentration

Question 10

describe osmosis

Answer 10

the movement of water

Question 11

Describe the fluid mosaic model

Answer 11

proteins embedded into the cell membrane help the movement of stuff through the cell wall

Question 12

What are channel proteins?

Answer 12

selective in allowing admittance of ions and small molecules

Question 13

What properties are required for simple diffusion

Answer 13

move down concentration gradient
lipid soluble
CH4
Vitamin D
CO2

Question 14

What kind of factors need to be in place to help the movement across a membrane via facilitated diffusion

Answer 14

moving down it’s concentration grade
with assistance from transmembrane carrier protein or channel proteins
Cl because it’s highly polar
glucose from liver to blood because it’s big and polar

Question 15

What conditions does a substrate need to be using active transport to move across a membrane?

Answer 15

up concentration gradient, or an electochemical gradient
requires energy from hydrolysis of ATP & assistance of transport protein
Na
Iodine into thyroid gland - up gradient

Question 16

What conditions apply for a substrate to use secondary active transport to cross a membrane?

Answer 16

up concentration gradient with help from something else that wants to go that way
eg glucose into the intestinal wall requires Na to bring it along for the dance party

Question 17

When a solution is said to be hypertonic relative to the inside of a vesicle, what does that mean? What are the implications?

Answer 17

Solutes cannot move though the lipid bilayer, water will flow out of the cell and it will shrink

Question 18

When the solution outside of the bilipid membrane has a lower concentration of solutes then the interior has
What will happen?
and what is this called?

Answer 18

the water will flow in

the solution is hypotonic

Question 19

What is an electrochemical gradient?

Answer 19

Ions move in response to a combined concentration and electrical gradient

Question 20

What is facilitated diffusion?

Answer 20

the passive transport of substances that would otherwise not cross a membrane, flow of ions, isotonic
needs a carrier protein
ie Gramicidin - membrane peptides = ion channel
best studied specialized for moving glucose into the cell

Question 21

What are aquiporins?

Answer 21

water pores allowing H2O to cross plasma membrane 10x faster than in the absence of it

Question 22

What are gated channels?

Answer 22

channels in the membrane that open or close in response to the binding of a particular molecule or to the change in an electrical charge on the outside of the membrane

Question 23

Describe active transport

Answer 23

against their electrical gradient
requires energy - ATP
Changes shape

Question 24

What is the distinguishing factor between saturated and unsaturated fats?

Answer 24

Saturated fats are all single bonds, therefore saturated

Unsaturated fats have a double bond, therefor they have a kink in their tail, don’t pack as well

Question 25

What are fats composed of?

Answer 25

3 FA ester linked to a # carbon molecule called glycerol

Question 26

What are the 3 most important types of lipids?

Answer 26

fats
Steroids
phospholipids

Question 27

Where do the ester linkages go?

What kind of link is it?

Answer 27

Ester happens between the COOH of the FA tail & OH of the glycerol head, it is a covalent bond

Question 28

What are the distinguishing factors of a steroid?

Answer 28

family of lipids distinguished by the 4 ring structure

estrogen, progesterone & testosterone derived from

Question 29

What are molecules containing only carbon and hydrogen?

Answer 29

Hydrocarbons
Isoprene or Octane
non polar - sharing of electrons =
therefor don’t dissolve in H2O

Question 30

Describe phospholipids

Answer 30

glycerol linked to a phosphate group and to either 2 chains of Isoprene or 2 Fatty acids
sometimes bonded to another small organic molecule

Question 31

Describe the properties of saturated lipids

Answer 31

single bonding on the carbons = saturated

pack in tightly, less permeability

Question 32

What happens to a as a hydrocarbon tail increase in length?

Answer 32

stiffer, and less permeable, interactions among tails are stiffer
ie wax
used by sea birds, otters, plant cells on exterior waxy layer

Question 33

Describe unsaturated FA

Answer 33

kink in tail due to double bond
liquid at room temp
liquid triglycerides are called oils

Question 34

what is the protein channel called that helps to facilitate the movement of water across a membrane?

Answer 34

aquaporin

Question 35

Define simple diffusion

Answer 35

The movement of a substance toward a lesser concentration

• the larger the concentration, the faster the movement
• size matters - moves faster when smaller
• lipid solubility diffuse readliy
• Charge - charge particles don’t move by simple diffusion

Question 36

Define facilitate diffusion

Answer 36

The movement of a substance down it’s concentration gradient

Question 37

What types of substances are moved via facilitated diffusion

Answer 37

• small charged particles - ions (Na, K, Cl)
• polar molecules (glucose, some aa)
• larger molecules (glucose, some aa)

Question 38

list properties of simple diffusion

Answer 38

faster than simple diffusion
selective
transporter subject to saturation, denaturation
dependent on both charge and conc. gradient

Question 39

Define active transport

Answer 39

the movement of a substance up it’s concentration gradient or electrochemical gradient via a transport channel

Question 40

What does an active transport protein in the membrane require to work/

Answer 40

the input of energy
Na/K pump - moves 3 Na out, 2 K in
requires ATP

Question 41

What is exocytosis?

Answer 41

the exit of materials from a cell

Question 42

What is endocytosis?

Answer 42

taking in materials into the cell

Question 43

Describe three different forms of endocytosis

Answer 43

• phagocytosis
• pintocytosis
• receptor-mediated endocytosis

Question 44

Define phagocytosis

Answer 44

cell eating
moves large particles into the cell
White blood cells phagocytose bacteria

Question 45

Define pintocytosis

Answer 45

cell drinking

moves extracellular fluid into the cell

Question 46

define receptor-mediated endocytosis

Answer 46

cells take up specific extracellular molecules via receptors on their surface

Question 47

List the 3 major types of lipids in the M.B. and their function

Answer 47

Phospholipids - Membrane structure
Glycolipid - signaling
steroid - membrane stabilization, cholesterol