Final Exam Flashcards
1
Q
A molecule contains…
A
Two or more atoms that are similar or different.
2
Q
Living systems do not contain phosphorous and sulfur because they are toxic. (T/F)
A
False
Phosphorus is an essential nutrient for living processes. It is a major component of nucleic acids and phospholipids, and, as calcium phosphate, it makes up the supportive components of our bones.
Sulfur is an essential element for the molecules of living things. As part of the amino acid cysteine, it is involved in the formation of proteins.
3
Q
How many electrons are found in the p subshell?
A
6
4
Q
What is the ranking of electronegativity, from least to most electronegative:
a. Cl, C, Na
b. Na, C, Cl
c. C, Na, Cl
d. Na, Cl, C
A
Na, C, Cl
5
Q
In living systems, ionic bonds are stronger than covalent bonds. (T/F)
A
False
So in biological contexts, always in water, ionic bonds are more suggestions than bonds-a convenient way of describing ion pairs, and are thus much much weaker than a covalent bond that doesn’t dissociate in the same way. But in a vacuum, the ionic bond is much harder to break than a simple covalent interaction.
6
Q
Determine the number of protons in an isotope that has the atomic number of 12, atomic mass number 26, charge of +2
A
12
same as atomic number
7
Q
Determine the number of neutrons in an isotope that has the atomic number of 12, atomic mass number 26, charge of +2
A
26-12 = 14
atomic mass - atomic number
8
Q
Determine the number of electrons in an isotope that has the atomic number of 12, atomic mass number 26, charge of +2
A
12-2 = 10
protons - charge
9
Q
Naturally occurring europium (Eu) consists of two isotopes with a mass of 151 and 153. Europium-151 has an abundance of 48.03% and Europium-153 has an abundance of 51.97%. What is the atomic weight of europium?
A
(151* 0.4803) + (153 * 0.5197)
152 amu
(mass1 * abundance1) + (mass2 * abundance2)
10
Q
atomic weight units
A
amu
11
Q
What is the molecular mass of C2H5OH? Carbon has 6 protons and 6 neutrons, hydrogen has 1 proton, and oxygen has 8 protons and 8 neutrons. Please include an appropriate unit.
A
46 g/mol (or amu or Da)
2(6+6)+5(1)+(8+8)+(1)
12
Q
molecular mass units
A
g/mol, amu, or Da
13
Q
Free energy is
G
A
Energy available to do work
14
Q
Potential energy is
A
Stored energy
15
Q
Entropy is
S
A
Unusable energy
16
Q
Enthalpy is
H
A
Total energy of the system
17
Q
Equilibrium is
A
Having minimal to no free energy
18
Q
For a reaction, the H of reactants is 10J, the H of products is 50J, the S of the reactants is 80 J/K and the S of the products is 70 J/K. The T of the system is 250K. What is G? Note that: G = H - TS.
and is this an endergonic or exergonic reaction?
A
H = 50J – 10J = 40 J
S = 70J/K – 80 J/K = -10 J/K
G = 40J – 250K * (-10 J/K)
G = 2540 J
Reaction is endergonic
19
Q
For a reaction, G is 300 J, S is 3 kJ/K, and T is 300K. What is H? Please provide appropriate units. Note that: G = H - TS
A
0.3kJ = H – 300 K * 3 kJ/K
H = 0.3kJ + 900 kJ
H = 900.3 kJ
20
Q
How many Joules are in a Kilojoule
A
1000 J
21
Q
If energy is needed to break bonds, why does catabolism result in energy release?
A
Because it also results new bond formation, which are more stable and release energy.
22
Q
What is the ranking for water forms, from least to most dense:
A
Vapor, solid, liquid
23
Q
Cohesion is
A
Attraction of identical molecules
24
Q
Adhesion is
A
Attraction of different molecules
25
High specific heat is
Responsible for reduced temperature
fluctuations in living systems
26
High heat of vaporization is
Responsible for cooling the surfaces of living systems
27
Hydration shell is
Cluster of water molecules around a
charged molecule
28
A solute dissolves in a solvent when solute-solvent attraction is greater than solute-solute attraction and solvent-solvent attraction (T/F)
True
29
neutral solution
equal number of H+ and OH-
30
acidic solution
more H+ than OH-
31
basic solution
more OH- than H+
32
When a basic substance enters the bloodstream, ______ is formed causing release of ___
Bicarbonate, H+ ions
33
cis isomer
molecules with the same connectivity of atoms. They feature same side groups placed on the same side of a double bond
34
structural isomer
same molecular formula but different arrangements of atoms
35
Trans isomers
molecules with same side groups placed on opposite sides of a double bond
36
methyl functional group
CH3
37
hydroxyl functional group
OH
38
sulfhydryl functional group
SH
39
amino/amines functional group
NH2; accepts H+ in living tissue to form NH3+
40
Phospholipids contain a hydrophobic tail of ________ and a hydrophilic head of ________. This makes phospholipids __________.
Fatty acids, glycerol-phosphate-choline, amphipathic
41
Glucose easily dissolves in water. There are 0.05 moles/L of sucrose in a solution. How many grams of sucrose are in 1 L of the solution? Its atomic mass is 180 g/mol. The mole of a substance is its mass divided by its atomic mass.
In 1 L of solution,
Mass of glucose = 0.05 mol * 180 g/mol = 9 g
42
triglyceride
molecule
a type of lipid with 3 fatty acid chains
43
lipid
macromolecule
long chain fatty acids which may be either free or combined with an alcohol by an ester linkage
44
saturated fatty acids
only single bonds
45
carboxyl functional group
COOH
## Footnote
can act as an acid and lose a proton to form a negatively-charged carboxylate ion (COO )
46
ketone functional group
CO
47
# ```
```
aldehyde functional group
COH
48
phosphate group
PO4^3-
49
Glycosidic bond occurs in
Carbohydrates
50
Ester bond occurs in
Lipids
51
Phosphodiester bond occurs in
Nucleic acids
52
Peptide bond occurs in
Proteins
53
Sucrose
disaccharide — it's composed of one unit of α glucose and one of fructose
54
sucrose is a monomer of
α glucosen and fructose
55
what glycosidic bond does sucrose have
α-1 2
| 1 carbon of glucose is connected to the 2 carbon of fructose
56
glycogen
polymer of alpha glucose
stores energy in animals
water insoluble
57
purine molecules
Adenine or Guanine
| two-carbon nitrogen ring bases
58
Pyrimidine molecules
Thymine or Cytosine or Uracil
| one carbon nitrogen ring base
59
What does an RNA nucleoside contain?
ribose sugar and AUGC bases
60
Primary protein structure consists of
a sequence of amino acids
61
α helix protein structure is
a coiled molecule
## Footnote
secondary protein structure
bonds form between every fourth amino acid and cause a twist in the amino acid chain
62
β pleated protein structure consists of
bonding between amino acids on two levels
## Footnote
secondary protein structure
hydrogen bonding between atoms on the backbone of the polypeptide chain
63
Tertiary protein structure results from
bending and folding of a polypeptide chain
64
Quaternary protein structure is
interaction between 2+ polypeptide chains
65
The overall nucleic acid synthesis reaction is energetically favorable because _ is converted to _ releasing _.
Triphosphate nucleoside, monophosphate nucleoside, pyrophosphate
66
change in G
arrow from products to reactants
67
exergonic
products below reactants
68
In what ways can enzymes lower activation change?
By inducing physical strain on the substrates.
By orienting two substrates so they can react more easily.
By adding charges to the substrate.
69
A reversible competitive inhibitor
Forms non-covalent attachment to the enzyme
at the active site
70
A reversible non-competitive inhibitor
Binds to the enzyme away from the active site
71
An irreversible inhibitor
Forms covalent attachment to the enzyme
72
An allosteric activator
Stabilizes the enzyme in active conformation
73
A feedback inhibitor
involves an end product binding to an enzyme
at the front of the pathway
74
an enzyme is said to be _ when the rate of product formation is maximal. The only way to increase the rate of product formation is to _ and _
saturated, synthesize new enzymes, activate already present enzyme molecules.
75
mol in Kmol
1000 mol
76
mmol in mol
1000 mmol
77
uniport transport protein
transports one solute
78
symport transport protien
transports two solutes on same side of membrane
79
# ****
antiport transport protein
transports 2 solutes to opposite sides of membrane
80
carbohydrates
outside of cell attached to proteins or lipids
81
cholesterol
little balls within phospholipid bilayer that alters fluidity
82
# ```
CaCl2
cannot pass through semipermeable membrane
breaks into Cl^- and Ca^2+
Chloride ion and calcium ion
83
what can pass through semipermeable membrane?
water - not salts or ions
| urea can
84
# ```
hypertonic body
the net movement of water will be out of the body and into the solution
85
hypotonic body
the net movement of water will be into the body and out of the solution
86
For the Na+/K+ ATPase pump, place the following steps in the right order/sequence (i.e.,
provide a, b, etc. in the right order) (5 points)
a. Two K+ ions bind to the pump.
b. Three Na+ ions and 1 ATP binds to the pump.
c. The pump is dephosphorylated, causing K+ ions to leave the pump.
d. The pump is phosphorylated, causing Na+ ions to leave the pump.
e. ATP is hydrolyzed to ADP
b, e, d, a, c
87
Diffusion is
Net movement of particles from areas of high to low concentrations
88
Equilibrium is
Equal concentrations across the membrane barrier
89
Osmosis is
Passive movement of water across a membrane
90
Osmotic pressure is
Force applied to a solution to prevent osmosis
91
Osmolarity is
Total number of solute particles per liter of water
92
two major membrane proteins involved in facilitated diffusion
## Footnote
write!
channels and carriers
93
active transport
used atp
94
bonds in NaCl
ionic
95
bonds in N2
non-polar covalent
96
bonds in H2O
polar covalent
97
bonds in CH4
non polar covalent
98
Phagocytosis is
cellular eating
99
Pinocytosis is
cellular drinking
100
Exocytosis is
secretion of materials outside of cell
101
Receptor-mediated endocytosis is
Intake of specific molecules into cell.
102
cells prefer a larger surface area-to-volume ratio because it helps maintain the cell’s metabolic activity through efficient transport of materials into and out of cell. (T/F)
True
103
Mitochondria
produce ATP
104
Golgi apparatus
Process and package materials for secretion
105
Lysosome
Carry out digestion and autophagy
106
Rough ER
Synthesize protein and adds carbohydrates to proteins
107
Peroxisome
Break down toxic peroxide compounds
108
Prokaryotes contain membrane-bound organelles (T/F)
False
109
Write down three differences between plant and animal cells
Animal cells contain (or plant cells lack) centrosomes (centrioles), lysosomes, and numerous small vacuoles. Plant cells contain (or animal cells lack) cell wall, chloroplast,
and large central vacuoles. (6 differences mentioned).
110
Cyanobacteria contain _ and are therefore _ . Archaea are mostly found in _ and have the characteristics of _.
chlorophyll, autotrophs, extreme conditions, both bacteria and eukaryotes
111
_ does not permit movement of any materials between cells. _ permit some material movement while _ allows ions and small molecules to pass through.
Tight junctions, desmosomes, gap junctions
112
Does microfilaments contain keratin, tubulin, or actin proteins?
actin
113
Does intermediate filaments contain keratin, tubulin, or actin proteins?
keratin
114
Does microtubules contain keratin, tubulin, or actin proteins?
tubulin
115
Can monomers be removed in microfilaments?
yes
116
Can monomers be removed in intermediate filaments?
no
117
Can microtubules be removed in intermediate filaments?
yes
118
Juxtacrine signaling
to touching cells
119
autocrine signaling
to own cell
120
Paracrine signaling
to nearby cell
121
For ligand-gated ion channels, place the following steps in the right order/sequence
a. Ions flow into the cell.
b. Neurotransmitter binds to its appropriate receptor.
c. The cell responds.
d. The receptor changes shape and opens
b, d, a, c
122
For G protein-coupled receptors (GPCRs), place the following steps in the right order/sequence
a. The alpha subunit of the G protein dissociates.
b. The signal binds to the GPCR, changing the conformation of the receptor.
c. The alpha subunit of the G protein activates an effector protein.
d. The alpha subunit of the G protein replaces GDP with GTP
b, d, a, c
123
enzyme involved in removal of phosphate groups
## Footnote
write!
phosphatase
123
enzyme involved in addition of phosphate groups
## Footnote
write!
kinase
124
enzyme involved in generation of cyclic AMP
## Footnote
write!
adenylyl cyclase
125
enzyme involved in cessation of cyclic AMP activity (by conversion to AMP):
phosphodiesterase
126
Removal of phosphate molecule activates an enzyme while addition of phosphate molecule inactivates an enzyme (T/F)
false
127
functions of rRNA
1. ensures proper alignment of tRNA anticodon and mRNA codon
2. It breaks bond between amino acid and tRNA. It also catalyzes formation of bond between two amino acids
128
In which organelle can already initiated protein translation continue?
rough ER
129
# [](http://)
For translation elongation, place the following steps in the right order/sequence
a. A newly charged tRNA enters A site, releasing uncharged tRNA from E site.
b. The peptidyl transferase enzyme adds methionine attached to tRNA in P site to the amino acid attached to tRNA in A site.
c. The ribosome shifts down one codon, moving the uncharged tRNA to E site and the tRNA carrying the two amino acids to P site.
d. The process continues until a stop codon reaches the A site.
e. At the A site, the anticodon of incoming tRNA binds to mRNA codon.
e, b, c, a, d
130
# [](http://)
anticodon
mRNA binding site
131
For translation initiation and termination, place the following steps in the right order/sequence
a. The large ribosomal subunit joins the initiation complex.
b. Methionine-charged tRNA binds to AUG codon.
c. At the A ribosomal site, a release factor binds to the stop codon.
d. The small ribosomal unit binds to mRNA at the 5’ end.
e. The release factor disconnects the polypeptide chain from tRNA molecule.
f. The translation elongation steps occur.
d, b, a, f, c, e
132
amino acid binding site
| of tRNA
three nucleotides on the 3’-OH end
133
mRNA attachment site
| of tRNA
three nucleotides at the bottom loop
134
What are the functional restrictions of DNA polymerase?
They can only copy single-stranded DNA.
They rely on an RNA primer to start synthesis of the daughter strand.
They can only add nucleotides to the 3’end.
135
For telomere extension by telomerase, place the following steps in the right order/sequence)
a. The telomerase’s RNA template binds to the 3’ overhang.
b. Telomerase and its RNA template shift, elongating 5’-3’ DNA strand.
c. Telomerase RNA acts as a template for addition of DNA nucleotides to 3’ overhang.
d. RNA primer removal following lagging strand synthesis creates 3’ overhang.
e. DNA polymerase elongates the 3’-5’ strand through addition of nucleotides.
d, a, c, b, e
136
DNA polymerase I
Fills gaps that arise during replication/repair
137
DNA polymerase II
Undertakes proofreading and repair/editing
138
DNA Polymerase III
Undertakes regular DNA synthesis
139
Write down three reasons why the cell tolerates a higher level of transcription errors vs. replication errors
1. Many RNAs are only a few thousand base pairs long & may have no or 1 error
2. RNA errors are not passed to next generation of cells
3. RNA has a short lifespan
140
single strand binding proteins
stabilizes ssDNA and keeps strands open
141
Primase
makes RNA primer
142
RNA Primer
5-10 nucleotides long
143
topoisomerase
relieves additional coiling
relieves tension caused by DNA supercoiling
144
Helicase
unzips
145
An RNA polymerase
adds complimentary nucleotides in 5’-3’ direction
146
A promoter
sets the start site for transcription
147
A transcription unit
is the DNA sequence being transcribed
148
A transcription factor
regulates initiation of transcription
149
why do eukaryote mRNA use 5' cap
protect the 5’-phosphate groups of RNA from enzyme
degradation in the cytosol
150
why do eukarayote mRNA use the addition of 3’-tail
makes RNA more stable and helps it get transported from
nucleus to cytosol
151
why do eukaryotes use splicing
removes introns that are commonly found in eukaryotic genes and mRNA
152
why do prokaryote mRNA not use 5' cap
prokaryotes undergo simultaneous transcription and
translation and therefore enzymes often cannot break their RNA before translation
153
why do prokaryote mRNA not use 3' cap
prokaryotic RNA is already in the cytosol and does not need
transportation
154
why does prokaryotic mRNA not use splicing
prokaryotic RNA rarely contains introns
155
# [](http://)
chromatin
condensed DNA - repeating units of nucleosomes
156
histone
each nucleosome contains 8
157
nucleosome
DNA wrapped around it
158
heterochromatin
Most condensed chromatin
Genes inaccessible & transcriptionally silent
159
euchromatin
Less condensed chromatin
Genes accessible & transcriptionally active
160
what is histone modification a mechanism of
Acetylation
161
what enzyme does histone modification use
Histone Acetyl Transferase (HAT)
162
acetylation
Reduces positive charges on lysine AA in
histones (neutralizes) --> weakens binding to DNA
to open up condensed chromatin (transcription can occur)
163
DNA methyltransferase
* adds methyl group to modify C to methylcytosine
* associated with gene inactivation and reduced transcriptional activity
164
maintenance methylase
catylyzes methylization of Cs in new DNA strands during DNA replication
165
demethylase
enzyme that removes methyl group from 5-mythylcytosine --> reactivates gene
166
two reasons why mammalian females have X chromosome inactivation
1. x chromosomes carry many more genes and males have one and females have two
2. both sexes should express similar amount of proteins
167
epigenetics
Study of how behaviors and
environment can cause changes to
gene expression
168
epigenetic examples (2)
histone modification and DNA
methylation
169
general (basal) transcription factores
rate of transcription low but is ready to transcribe RNA
TFIID binds to TATA, general trascription factor, RNA polymerase II
170
regulatory transcription factors
1. Sequences (like enhancers and silencers) that bind specific TFs (activators and repressors) may be far from transcription start site
2. Mediator binds to basal transcription apparatus
3. DNA bending allows mediator to interact with distant TFs and the basal transcription apparatus to alter transcription rate
171
miRNA steps
1. Single transcribed RNA molecule folds onto itself to form dsRNA
2. The enzyme Dicer cleaves dsRNA to produce miRNA
3. Ss miRNA combines with proteins to form RNA-induced silencing complex (RISC)
4. RISC inhibits translation or causes degradation of complementary RNAs
5. miRNA works on more RNA molecules than siRNA
172
siRNA
1. Both strands of DNA are transcribed to produce complimentary RNA molecules that combine to produce dsRNA
2. The enzyme Dicer cleaves dsRNA to produce siRNA
3. Ss siRNA combines with proteins to form RNA-induced silencing complex (RISC)
4. RISC inhibits translation or causes degradation of complementary RNAs
5. siRNA works on fewer RNA molecules thanmiRNA
173
ferratin formation process (translational regulation)
protein that binds to and transports iron in the blood and cytoplasm
- translational repressor binds to ferritin mRNA when Fe low, prevents ribosome attachment
- when fe high, fe binds to repressor and ferrit mRNA detaches --> ribosome binding and translational process occurs
