T1M1

Question 1

Streptococcus salivarius

Answer 1

a normal inhabitant of the upper
respiratory tract and oral cavity

Question 2

Staphylococcus haemolyticus

Answer 2

Resides on skin

Question 3

Bacteroides thetaiotaomicron

Answer 3

A predominant intestinal bacteria

Question 4

Cell

Answer 4

A membrane bound structure containing macromolecules

Question 5

Four Classes of Macromolecules

Answer 5

1. Nucleic acids (DNA & RNA)
2. Proteins
3. Polysaccharides
4. Phospholipids

Question 6

Membranes

Answer 6

Separate an internal environment form the external environment. This allows these distinct environments to have different chemical composition.

Question 7

Cell membrane is made up of

Answer 7

Lipids. Each of these macromolecules has hydrophobic and hydrophilic properties that allow “stacked” lipid bilayers to form.

Question 8

Water molecules interact with

Answer 8

the head regions, but not the tails of phospholipids

Question 9

lipid aggregates form with or without energy?

Answer 9

Spontaneously, without the use of any energy.

Question 10

Factors affecting the fluidity of cell membranes (4)

Answer 10

1. Unsaturated or saturated fatty acids
2. Number of carbons in the fatty acid tails
3. Temperature
4. The presence or absence of cholesterol

Question 11

Lower permeability

Answer 11

Less fluid membrane with fewer unsaturated fatty acids and more cholesterol.

Question 12

Higher Permeability

Answer 12

More fluid membrane with more unsaturated fatty acids and less cholesterol.

Question 13

Selectively permeable

Answer 13

The ability of cell membranes to control the traffic of substances into and out of the cell and its organelles

Question 14

Passive diffusion

Answer 14

from areas of high to low concentration (along a
gradient)

Question 15

Passive transport

Answer 15

or facilitated diffusion: from areas of high to low
concentration (along a gradient)

Question 16

Active transport

Answer 16

molecules move against the concentration gradient
(fueled by energy from the hydrolysis of ATP)

Question 17

Osmosis

Answer 17

the transport of water across membranes. Water diffuses from a less concentrated solution (hypotonic) to a more concentrated solution (hypertonic)

Question 18

Aquaporins

Answer 18

Allow rapid transport of water, exclusively permeable to water, protein channels allow water to move across the cell membrane through osmosis. Movement across is concentration gradient dependent.

Question 19

What moves across membrane easily

Answer 19

gases and hydrophobic molecules (O2, CO2, N2, steroid hormones)

Question 20

what can trickle through the membrane

Answer 20

small uncharged polar molecules (urea, glycerole)

Question 21

what cannot go through the membrane

Answer 21

large, charged polar molecules (glucose, sucrose, ions)