Cell Structure (T1M1)

Question 1

What is a eukaryotic cell

Answer 1

True nucleus with genetic material

Plant, animal, fungi

Question 2

What is a prokaryotic cell

Answer 2

No true nucleus

Bacteria

Question 3

What is a microbiome

Answer 3

Populations of microbes in an environment

Question 4

Give some examples of bacteria found in a healthy body

Answer 4

Streptococcus salivarus
Upper respiratory tract, creates tooth plaque

Staphylococcus haemolyticus
On skin but dangerous in body (staph infections)

Bacteroides thetaiotaomicron
Digestive enzymes in colon

Question 5

The four classes of macromolecules are:

Answer 5

Nucleus acids

Proteins

Carbohydrates / Polysaccharides

Fats / Phospholipids

Question 6

What are some purposes for a cell membrane?

Answer 6

Separate environments with different chemical compositions

Protect from toxins

Facilitate entry and exit of wastes

Question 7

Describe the composition of a phospholipid

Answer 7

The head contains a polar group at the top, followed by a phosphate group attached to a glycerol (C3H8O3)

Fatty acid tails are attached to the glycerol

Question 8

Phospholipid heads are _______ while the tails are _______

Answer 8

hydrophilic, hydrophobic

Question 9

Define ampipathic

Answer 9

Both hydrophobic and hydrophilic

Question 10

Fatty acid tails have:

How many carbons?

What types of bonds?

What type of shape?

Answer 10

16-18

Single aka saturated, double aka unsaturated

Double bonds cause kinks

Question 11

Describe the structure of steroids

Answer 11

4 hydrocarbon ring structure

Eg cholesterol

Question 12

What are lipid micelles?

Answer 12

Aggregation of free lipids that forms a ball with hydrophobic tails on the core and hydrophilic heads on the surface.

They can absorb fat soluble vitamins and other lipids.

Question 13

What are some factors that affect cell membrane fluidity? How do the affect fluidity?

Answer 13

More unsaturated fatty acids lead to more kinks in the membrane, which increases fluidity.

Longer carbon chains reduces fluidity

Higher temperature means more fluidity

More cholesterol at NORMAL temperatures means less fluidity

More cholesterol at LOWER temperatures means more fluidity

Question 14

About how much of the bilious membrane is cholesterol?

Answer 14

50%

Question 15

True or false: more fluid membranes are more permeable

Answer 15

True

Question 16

How do each of the following molecules cross the cell membrane?

Small nonpolar molecules

Gases

Hydrophobic molecules

Small ions

Water soluble materials

Large charged and polar molecules

Answer 16

1-3 pass through the easiest

4 may need some assistance

5 must pass through transport proteins

6 basically don’t cross at all

Question 17

Differentiate between:

1) passive / simple diffusion
2) passive transport or facilitated diffusion
3) active transport

Answer 17

1) high to low ccn, directly across the bilaye, includes (gases, water, lipid-soluble molecules, polar molecules)
2) high to low ccn,through embedded proteins, no ATP required, transports ions and hydrophilic molecules
3) low to high ccn, through transport proteins and ATP

Question 18

What is osmosis

Answer 18

Passive transport across a membrane

Question 19

How does osmosis change volumes and concentrations between two solutions?

Answer 19

Water diffuses from a less concentrated area (hypotonic) to a more concentrated (hypertonic) area

Diluted do not move across a membrane

The process creates equal osmolarity

Question 20

What are aquaporins

Answer 20

Transport water through osmosis in to and out of the cell

Question 21

Define

1) isotonic
2) hypotonic
3) hypotonic

Answer 21

1) osmolarity interior = osmolarity exterior

2) osmolarity interior > osmolarity exterior
water flows in to cell

3) osmolarity interior < osmolarity exterior
water flows out of cell

Question 22

Define:

1) primary active transport

2) secondary active transport

Answer 22

1) proteins use ATP directly to pump against the gradient

2) neighbouring proteins benefit off of the electrochemical gradients created by primary transport, indirect use of ATP

Question 23

Describe the Na-K pump

Answer 23

For every 3 Na+ pumped out, 2K+ are pumped in

3Na+ bind to the protein

ATP gives up phosphate group

P binds to protein, creating the necessary confirmation to release Na+ outside of the cell

2K+ bind to protein, P group breaks off, protein confirmation changes

K+ enters the cell

Creates a more positively charged cell exterior