Bio Lab Exam 2 Flashcards
1
1) FALSE
2
2) TRUE
The concentration of a solution is commonly
listed as molarity.
3
3) FALSE
The positive control is a known substance
that is expected to be positive when the test
reagent is added. It is used to be sure the test
solution is working properly.
4
4) FALSE
5
5) FALSE
Since lipids are nonpolar, they dissolve in nonpolar solvents.
6
6) TRUE
Phenolphthalein is used as a pH indicator
because it turns red in basic conditions.
7
7) FALSE
8
8) TRUE
Recall that the Fluid Mosaic Model uses a
phospholipid bilayer as its foundation. In
this bilayer, the polar phospholipid heads
face out, and the nonpolar phospholipid tails
avoid water by remaining in the interior of
the membrane. The membrane interior is
nonpolar, so nonpolar molecules move
across readily.
9
9) FALSE
Water will flow from an area of high water
potential to an area of low potential.
10
10) [A, B]
Stock solutions only have to be diluted, not
made from scratch each time they are
required.
11
11) [A, D]
12
12) [A, B]
Carbohydrates are the main ingredient in
soda and candy.
13
13) [D]
Steak is the only choice with the majority of
its calories from protein.
14
14) [C]
Butter is mainly saturated fat.
15
15) [B, C]
DNA exclusively can be detected using Dische diphenylamine and has thymine as a nitrogenous base.
Both DNA and RNA have cytosine as a
nitrogenous base. Ribose has an group at C2, while DNA has H in that position.
16
16) [A, B, C, D]
The speed at which diffusion occurs is
influenced by the size, polarity, solubility,
and especially by the concentration gradient
of molecules.
17
17) [B, C]
Dialysis tubing has pores of a certain size,
consequently, the size of a molecule is a
determining factor in whether the molecule
will be able to pass through dialysis tubing.
Larger molecules may be too large to diffuse
through the tubing.
A great difference between the
concentration of a substance outside of the
dialysis tubing compared to its concentration
inside the dialysis tubing is known as a steep
concentration gradient. The steeper the
concentration gradient, the faster diffusion
will occur.
18
18) [A, B, D]
19
19) [A, B, C, E]
The fluid mosaic model of cell membrane
structure has a phospholipid bilayer as a
foundational layer. Phospholipids are
arranged with their heads pointing out and
their tails facing each other in the interior of
the membrane. Interspersed amongst these
phospholipids are integral proteins, which
go all the way through the bilayer.
Peripheral proteins occur along the side of
the membrane, but do not penetrate the
phospholipid bilayer. Carbohydrates extend
in chains from the outside of the cell
membrane.
20
20) [A, B, C, D]
All of these would be possible if human
tissue could maintain viability after freezing.
All of these would be possible if human
tissue could maintain viability after freezing.
21
21) B
22
22) B
23
23) A
By definition, the number of grams per 100
ml refers directly to the percent of solute in
that solution.
24
24) E
There are always 12 items in a dozen.
25
25) B
The number of molecules in a mole is
similar to the idea of a dozen. One dozen
elephants indicates 12 individuals, and one
dozen mice indicates 12 individuals. It does
not matter that elephants are larger than
mice; the concept relates the number of
individuals only, which is 12 per dozen.
One mole of a substance always indicates
molecules. One mole of
water weighs 18g, while one mole of
glucose weighs 180g. One mole of water has
the same number of molecules as does a
mole of glucose, because the number of
molecules per mole does not change. A mole
indicates the number of individual
molecules present, just as a dozen does.
26
26) B
One atom of Mg weighs 24
One atom of S weighs 32
One atom of O weighs 16
Weight of = 24 + 32 + 4(16)
27
27) C
The molecular weight of is 120
g/mole. 120 g/mole (0.5 moles/L) = 60 g/L
