Midterm II Slide Notes Flashcards
1
Q
What is metabolism?
A
The totality of an organism’s chemical reactions; the transformation of energy from one form to another.
2
Q
What does metabolism include?
A
Catabolic and Anabolic Reactions
3
Q
What do enzymes do with the presence of substrates?
A
They convert substrates to products.
4
Q
Metabolism is a series of linked _____ reactions.
A
Enzymatic
5
Q
What are anabolic reactions?
A
The building of complicated molecules from simple building blocks; energy is consumed linked in a bio synthetic pathway.
6
Q
What are catabolic reactions?
A
The breaking down of complicated molecules to simpler ones; energy is RELEASED.
7
Q
Define Bioenergetics
A
The study of how energy flows through living organisms.
8
Q
Define Kinetic Energy
A
Energy associated with motion.
9
Q
Define Thermal Energy
A
The KE associated with the random movement of atoms and molecules.
10
Q
_____ is thermal energy in transfer between objects.
A
Heat
11
Q
Define Potential Energy
A
The energy that matter possesses because of its location or structure.
12
Q
Define Chemical enERGY
A
The potential energy available for release in a reaction.
13
Q
Metabolism is based on the laws of _____.
A
Thermodynamics
14
Q
Define Thermodynamics
A
The study of energy transformations.
15
Q
An isolated system, such as that approximated by liquid in thermos, is _____ to exchange energy or matter with its _____.
A
Unable-Surroundings
16
Q
Organism are an example of what type of system?
A
Open System; energy and matter can be transferred between the system and its surroundings.
17
Q
What is the first law of thermodynamics? What is another name for it?
A
The energy of the universe is constant; energy can be transferred and transformed, but it cannot be created or destroyed. It’s also called the principle of conservation of energy.
18
Q
What does energy transfer increase in the universe?
A
Increases the entropy (disorder) of the universe.
19
Q
What is the second law of thermodynamics?
A
During every energy transfer or transformation, some energy is usable and some is often lost as heat; energy transformations and transfers increases the entropy of the universe.
20
Q
Define Entropy
A
The measure of molecular disorder, or randomness.
21
Q
What happens to some of the energy that is transferred in cellular reactions?
A
Some of it is lost as heat.
22
Q
Define Spontaneous Process
A
Processes that can occur without an input of energy; they can happen slowly or quickly. They INCREASE the entropy of the universe.
23
Q
Define Non-Spontaneous Process
A
Processes that decrease the entropy of the universe; no energy input is required.
24
Q
Do all biological activities accompany a release of heat which increases entropy?
A
YES
25
What is the equation for Gibbs Free Energy?
Delta G= Delta H- TDELTAS ; Delta G can also be written as G products - G Reactants
26
What does Delta G mean?
The change in free energy; energy available to do work when the temperature and pressure are uniform as in living cells.
27
What are the two types of reactions when it comes to Gibbs free energy?
Exergonic and Endergonic
28
What happens in exergonic reactions and how can they be regarded?
The reactants have more energy than products; energy is released; they can be regarded as SPONTANEOUS.
29
What happens in endergonic reactions? How can they be regarded?
Reactants have less energy than the products; energy is required; it can be regarded as NONSPONTANEOUS.
30
If DELTA G is negative, what can we say?
That the reaction is spontaneous and that it is EXERGONIC.
31
Do living systems ever reach equilibrium?
No, not until they die.
32
What are the three types of main work that the cell does?
Chemical-Transport-Mechanical
33
Define Chemical Work
Pushing endergonic reactions.
34
What is an example of transport work done in cells?
Pumping substances against the direction of spontaneous movement.
35
What is an example of mechanical work?
Contraction of muscle cells.
36
How does ATP power cellular work?
By coupling endergonic and exergonic reactions; energy coupling.
37
What is ATP consisted of?
Ribose (Sugar), adenine (a nitrogenous base), and three phosphate groups.
38
What does phosphorylation mean?
Addition of a phosphate group to a substance.
39
Define Activation Energy
The energy that is needed to start a chemical reaction. It is often supplied in the form of thermal energy that the reactant molecules absorb from its surroundings.
40
How do enzymes speed up metabolic reactions?
By lowering the activation energy.
41
Define Catalyst
A chemical agent that speeds up a reaction without being consumed by the reaction.
42
An _____ is a catalytic protein.
Enzyme
43
Define Substrate
A reactant that an enzyme acts on.
44
How is an enzyme-substrate complex formed?
The enzyme binds to its substrate/
45
Define Active Site
The region on the enzyme where the substrate binds.
46
Define Induced Fit
Induced fit of a substance brings chemical groups of the active site into positions that enhance their ability to catalyze the reaction.
47
How are substrates held in the active site?
By weak interactions, such as hydrophobic or ionic bonds.
48
Do the enzymes lower the time required to turn reactants into products?
Yes
49
What does it mean for enzymes to have optimal conditions?
This means that the enzyme can perform at certain temperatures and pHs.
50
Define Cofactors
Non-protein enzyme helpers. Can be organic or inorganic
51
What are organic cofactors called?
Coenzymes; they include vitamins.
52
Define Allosteric Site
Any site outside of the active site is called the allosteric site.
53
What do competitive inhibitors do?
They bind to the active site of an enzyme, competing with the substance.
54
What do non-competitive inhibitors do?
They bind to another part of the enzyme, causing the enzyme to change shape and making the active site less effective. In other words, non-competitive inhibitors bind to an allosteric site.
55
What are some examples of inhibitors?
Toxins and Antibiotics.
56
How does feedback inhibition work?
When a substrate binds to the allosteric site, the protein changes shape and the active site is no longer available.
57
The membrane of a cell is _____.
Hydrophobic
58
What are redox reactions?
Reactions that involve the oxidation and reduction of a substance.
59
What happens when something is oxidized?
It loses an electron. OL
60
What happens when something is reduced?
It gains an electron. RG
61
An oxidizing agent gets _____.
Reduced
62
O2 becoming H2O in the product side is an example of it getting _____.
Reduced
63
Define Reducing Agent?
The electron DONOR is called the reducing agent. RAD
64
An oxidizing agent _____ electrons.
Accepts
65
When electrons get transferred from a less electronegative substance to a more electronegative substance, is it endergonic or Exergonic?
EXERGONIC
66
In the reaction of breakdown of glucose, is glucose oxidized or reduced?
Oxidized. GO
67
What is NAD+?
The most versatile electron ACCEPTOR in cellular respiration.
68
What are some important things to note about NAD+?
A coenzyme key in many biological oxidation reactions; electrons from organic compounds are usually first transferred to NAD+.
As an electron acceptor, NAD+ functions as an OXIDIZING agent during cellular respiration.
Each NADH (reduced form of NAD+) represents stored energy that is tapped to synthesize ATP.
69
Why is NAD+ such as good electron carrier?
Because it can cycle easily between its oxidized form and its reduced form (NADH).
70
What are the stages of cellular respiration?
Glycolysis (breaking down of glucose to two pyruvate molecules)- The Krebs Cycle (completion of the breakdown of glucose)- Oxidative Phosphorylation (accounts for the majority of ATP Synthesis)
71
Glycolysis happens in the _____; citric acid cycle and oxidative phosphorylation happen in the _____.
Cytosol-Mitochondria
72
What happens in substrate based ATP synthesis?
Kinase converts ADP to ATP.
73
What is the net return from Glycolysis?
2 ATP- 2NADH- 2 Pyruvate
74
What is aerobic respiration?
A chemical process in which oxygen is used to Kate ATP
75
What is included in Anaerobic Respiration?
Fermentation which includes alcohol and lactate production.
76
What are some important things to note about anaerobic respiration?
The final electron acceptor of the ETC uses (SO4)2-; the sulfate accepts electrons and gets reduced to SH2.
77
What essentially happens in fermentation?
The main objective is to recycle “waste material” (pyruvate and NADH) to get NAD+ to make more glucose; NADH gets oxidized to NAD+
78
Where does the Krebs Cycle occur?
In the mitochondrial matrix.
79
What is the net return from the Krebs Cycle?
6 NADH, 2ATP, 2FADH2
80
How many CO2 are released during the Krebs cycle?
2
81
What is the role of coenzyme A in the Krebs cycle?
Brings up the potential energy; goes inside the mitochondria.
82
What are multiprotein complexes?
Proteins that interact with each other in the same vicinity.
83
What essentially happens in the ETC?
Electrons are passed to progressive more electronegative complexes until they are accepted by oxygen to make water.
84
Can NADH or FADH2 create more spontaneous reactions?
NADH
85
What is the general equation for what happens in the ETC?
2e- + 2H+ 1/2 O2 —-> H2O
86
Is substrate based phosphorylation slower or oxidative phosphorylation?
Substrate Based
87
For the transfer of every _____ electrons, a _____ is released during the ETC.
2- Proton
88
What happens in oxidative phosphorylation?
As we go form one electron acceptor to the next in the ETC, H+ is being pumped out. The concentration of H+ in the inter membrane space builds up, creating an electrochemical gradient. The H+ goes down its concentration gradient (high concentration to low concentration), allowing for the turning of ATP Synthase. ATP synthase turning jams a phosphate group to ADP, producing ATP.
89
What is photosynthesis consisted of?
Light Dependent Reactions and Calvin Cycle.
90
What happens in Light Dependent Reactions?
Light energy plus water and carbon dioxide leads to the production of ATP, NADPH, and O2. They happen in the thylakoid membrane of the chloroplasts.
91
Define Wavelength
The distance between crests of the electromagnetic waves.
92
What is the range for visible light in the spectrum?
380 nm to 750 nm.
93
In the light dependent reactions, what regions have what concentration of H+?
There is a higher concentration of H+ in the thylakoid lumen (interior) compared to the stroma.
94
What happens in the Calvin Cycle
CO2 from the atmosphere and NADPH and ATP are used to produce Phoshoglyceraldehyde; ribulose biphosphate (a 5 carbon structure w/ 2 phosphates) combines with CO2 (an endergonic reaction). The energy comes from the oxidation of ATP and NADPH. From there, PGAL gets produced and the majority of it is used to reproduce RuBP. The Calvin Cycle happens in the stroma.
95
What are the three types of communications that cells undergo?
Direct Contact Signaling (cell-cell contact and cell-junctions)
Local Signaling (Autocrine, Paracrine, and Synaptic).
Long Distance Signaling (hormonal)
96
What are gap junctions?
Localized sets of channels.
97
Which ER contains ions?
Smooth ER
98
How can neurons communicate by gap junctions?
Through the body of the cell.
99
What happens in contact trough gap junctions?
Cells extremely close together in the vicinity interact with each other through gap junctions, allowing for the exchange of material.
100
How do cells communicate through cell-cell recognition?
The protein of one cell binds to the receptor of another cell, allowing for the distribution and exchange of material.
101
What happens in autocrine signaling?
A cell influences itself; signals bind to the receptor on the same cell.
102
How do cells communicate in paracrine signaling?
Cells relatively close together in the vicinity interact with each other through a secretory vesicle in the main cell excreting material and influencing the other target cells.
103
How do cells communicate in synaptic signaling?
Neurotransmitters from one neuron get diffused across the synapse (the small space in between neurons) and influence the other neuron.
104
Endocrine signaling is _____ distance and has to be _____.
Long Distance-Precise
105
Define Ligand
A molecule that binds to another (usually larger) molecule.
106
Define Signal Transduction
The series of steps in which a cell converts a signal into a response.
107
What are some examples of ligands?
Growth Factors, Hormones, and Neurotransmitters. GHN
108
Growth factors are associated with the _____ of cells.
Growth
109
What are G proteins?
Specialized proteins which have the ability to bind GTP and GDP.
110
What generally happen in the functioning of a G-protein linked receptor?
GDP is bound to an inactive protein; when the ligand binds to the GPCR, GTP binds to the G protein and GDP is released. The protein with the GTP binds to the inactive enzyme, making it active. After the process is done, GDP is bound to the inactive protein and inorganic phosphate is released.
111
The G-Proteins function like a _____. They are either _____ or _____.
Switch-On-Off
112
What type of molecule is cAMP?
Second Messenger
113
What are second messengers and what are some examples?
Small molecules or ions that relay signals received by cell-surface receptors to effector proteins. Examples are cAMP, IP3, Ca2+, Na+
114
What happens in tyrosine kinase receptors?
They exist as monomers in the cell with an extra cellular singla receiving portion and an intracellular portion containing tyrosines. Once the signaling molecule binds to the extra cellular side, dimerization occurs. Dimerization activates the tyrosine kinase region of each monomer, adding a phosphate group from an ATP to the other monomer. Once the receptor is fully activated, it is recognized by relay proteins. Relay proteins bind to a specific phosphorylated tyrosine, changing shape and leading to a transduction pathway and a cellular response.
115
How do ligand-gated ion channel receptors function ?
Without the binding of a ligand, the gate remains closed. Once the ligand binds to the receptor, the gate is open and allows for the passage of ions into the membrane.
116
How do intracellular receptors function?
A hormone, (testosterone for example), binds to the intracellular receptor protein. The hormone receptor complex then goes inside the nucleus, into the DNA, and alters gene expression.
117
What is a key factor for distinguishing living and non-living things?
The ability to reproduce.
118
How does cell division occur in prokaryotes?
They do not have a nucleus so they divide by binary fission (separation in the middle). The chromosome is consisted of a circular DNA molecule and is divided.
119
How do unicellular eukaryotes divide?
Through longitudinal division.
120
A typical human cell has _____ of DNA; this is _____ times bigger than the diameter of the cell. The human has about _____ genes.
2 meters- 25,000- 40,000
121
Define Genome
The entire collection of genes characteristic of a particular species.
122
Define Haploid
A cell containing only 1 set of chromosomes. (1n)
123
Define Diploid
A cell containing 2 sets of chromosomes (2n); one set from each parent.
124
Define Polyploid
A cell containing more than 2 sets of chromosomes.
125
How do humans start off as?
As one cell (a fertilized egg); the fusion between an ovum and a sperm.
126
Which cells in our body are haploid?
Gametes (1n); sex cells.
127
Which cells in our body are diploid?
Somatic Cells (2n).
128
What are examples of when normal controlled cell division occurs?
Reproduction-Replacement of Aged Cells-Healing of Wounds
129
What is an example of abnormal cell division?
Cancer and Keloids
130
Define Mitosis
A multi step complex process that passes along the genome from one cell to its daughter cells. The daughter cells are identical to each other and the parental cell.
131
What are the key steps in cell division and what is each step consisted of?
Interphase (G1, S Phase, G2); Mitosis (Prophase-Prometaphase-Metaphase-Anaphase-Telophase)-Cytokinesis
132
When cells are not dividing, what are they doing?
They are in the G0 phase (working).
133
In which step does the cell spend most of its time in? Shortest time?
Interphase is the longest; Mitotic phase (mitosis and cytokinesis) the shortest.
134
Define Chromosome
A large piece of DNA alongside its associated proteins.
135
Define Centromere
A condensed region of DNA; the region of the condensed chromosomes where the 2 sister chromatids join.
136
Why are chromosomes most visible during mitosis and meiosis?
Because the DNA is folded and coiled onto itself.
137
When are condensed chromosomes present?
From prophase to anaphase.
138
In which phase do the sister chromatids separate?
They separate in Anaphase; each chromatid becomes its own chromosome.
139
Define Chromatin
The complex of DNA and proteins (histones) that make up each chromosome.
140
Define Euchromatin
The less condensed form of chromatin that is available for transcription.
141
Define Heterochromatin
The very highly condensed form of chromatin
142
What is going on in the G2 Phase?
Centrosome with centriole pairs, nuclear envelope, nucleolus, and plasma membrane are all present.
143
What goes on in Prophase?
The mitotic spindle (a structure made of micro tubules responsible for organizing chromosomes) begins to form- The chromosomes start to condense- The nucleolus (part of the nucleus where ribosomes are made) disappears.
144
What goes on in Prometaphase?
Chromosomes become even more compact- Nuclear Envelope breaks down- Further growth of the mitotic spindle.
145
What goes on in Metaphase?
All the chromosomes align at the metaphase plate- Kinetochore Microtubules from opposite centrosomes are connected.
146
What goes on in Anaphase?
The microtubules push poles apart, resulting in the separation of chromosomes and formation of sister chromatids (each now its own chromosome)
147
What goes on in telophase?
The chromosomes start to decondense-Spindle begins to disappear- Nuclear membrane and nucleolus form. Basically, it is the opposite of prophase.
148
What goes on in cytokinesis?
The cytoplasm divides to form two new cells.
149
Define Kinesin
A motor protein that transports the chromosomes on microtubules.
150
Cytokinesis is accomplished through the utilization of _____.
Microfilaments.
151
Generally speaking, what is the main purpose of meiosis I and what is the main purpose of meiosis II?
Meiosis I: separation of homologous chromosomes
Meiosis II: separation of sister chromatids.
152
Define Homologous Chromosomes
Chromosome that are similar in structure and size, have the same genes, you get one from each parent. They can have different alleles. One from father and one from mother.
153
Define Sister Chromatids
Replicated forms of a chromosome joined together by the centromere.
154
Define Synapsis
The pairing of replicated homologous chromosomes during prophase I of meiosis I.
155
Define Crossing-Over
The exchange of genetic material between non-sister chromatids during synapsis in meiosis I.
156
Define Chiasma
The region of the non-sister chromatids where exchange of the genetic material takes place during Meiosis I.
157
What is the outcome obtained from meiosis?
4 haploid daughter cells that are different from the parental cells.
158
What happens in prophase I?
The homologous chromosomes pair and exchange genetic information. This happens at the chiasma.
159
What happens in metaphase I?
The tetrads line up at the metaphase plate.
160
What happens in anaphase I?
Homologous chromosomes separate, 2 chromosomes are left in each cell.
161
What are some key differences between meiosis and mitosis?
Mitosis results in two daughter cells with 2n and meiosis results in 4 daughter cells with 1n.
Meiosis has 2 divisions whereas mitosis only has 1 set of divisions.
Synapsis (the pairing of homologous chromosomes in prophase I) is unique to meiosis and does not occur in mitosis.
162
What are contributors to genetic variation in species that reproduce sexually?
Independent Assortment of homologous chromosomes at the metaphase plate in meiosis I- Crossing Over- Random Fertilization
163
What does independent assortment entail?
The homologous chromosomes can line up in a myriad of ways in the metaphase plate at the end of metaphase in meiosis I.
164
Each gamete has a _____ chance of having paternal or maternal chromosomes or of having both.
50:50
165
The number of possible combinations for the gametes is _____ where n is the number of chromosomes in the genome.
2^n
166
How does the production of no ATP affect replication?
If no ATP is produced, replication cannot happen.
167
What are the cell cycle control proteins?
Kinases and Cyclins
168
Define Kinases
Enzymes that activate or de-activate other proteins by phosphorylating them.
169
What are cyclins and what are types of cyclins?
Cyclins get their name because they cycle in concentration throughout the cell cycle. The two types of cyclin are cdk2 and cyclin B
170
How is MPF (M-Phase promoting factor) formed?
Through the combination of cdk2 and cyclin B
171
Which of the cyclins are always present in high amounts?
Cdk2
172
What are some affects of MPF being activated?
Stimulates the condensation of chromosomes- Early formation of the spindle- Breakdown of the nuclear envelope.
173
How is MPF inactivated?
When cyclin is degraded.
174
When is MPF activated?
At the G2 checkpoint (G2-Prophase)
175
When is MPF active? When is MPF inactive?
From prophase to the end of anaphase.
At the beginning of telophase, the MPF is inactivated.
176
How do the sister chromatids separate during anaphase?
Cohesions, Securin, and Separase
177
What is the function of separase?
It degrades cohesins, allowing for the sister chromatid separation during anaphase.
178
What does the APC (Anaphase Promoting Complex) do?
It stimulates the degradation of a protein called securin in the proteosome; it also tags cyclin so it can be degraded in the proteosome, leading to the loss of MPF function.
179
What is a karyotype?
The display of chromosome pairs of a cell arranged by size, shape, and staining patterns.
180
How do you prepare a karyotype?
You obtain sample cells from an individual, plate them on a Petri dish, stop their division in metaphase, stain them, and examine them.
181
What does aneuploidy mean?
A chromosomal alteration in which certain chromosomes are present in extra copies or deficient in #.
182
What does non-disjunction mean?
The improper separation of homologous chromosomes in meiosis I or the improper separation of sister chromatids in meiosis II.
183
Define DNA Replication
The process by which a DNA molecule is replicated.
184
_____ is the genetic material.
DNA
185
Define Transformation
A change in genotype and phenotype due to the assimilation of external DNA by a cell.
186
Define Bacteriophage
A virus that infects bacteria; also called a phage.
187
Define Virus
An infectious particle inacabable of replicating outside of a cell, consisting of RNA or DNA genome surrounded by a protein coat,
188
In Hershey’s experiment, what was the DNA tagged with?
The protein was tagged with a radioactive isotope of sulfur and the DNA was tagged with a isotope of phosphorus.
189
The two sugar phosphates were observed by Watson to be anti-parallel. What does this mean?
Means that the subunits ran in opposite directions.
190
Adenine can form _____ hydrogen bonds with thymine and guanine can form _____ hydrogen bonds with cytosine.
2-3
191
Define the Origin of Replication
Sites where the replication of a DNA molecule begins, consisting of specific sequence of nucleotides.
192
Define Replication Fork
A Y-shaped region on a replicating DNA molecule where the parental strands are being unwound and the new strands are being synthesized.
193
Define Helicase
An enzyme that untwists the double helix of DNA at the replication forks, separating the two strands and making them available as template strands.
194
Define Single-Strand Binding proteins
A protein that binds to the unpaired DNA strands during replication, stabilizing them and holding them apart while they serve as templates for the synthesis of complementary strands.
195
Explain everything about Griffith’s experiment.
Isolated 2 strains for bacteria that caused pneumonia in mice; S bacteria caused death; r bacteria led to no death. The S bacteria had a capsule that prevented them from being recognized by the immune system. The R bacteria lacked that capsule.
Through heating the S-bacteria, he killed them. After mixing it with the living R cells, the mice still died. Living S cells were somehow found in the sample of blood from the mice and bacterial transformations were discovered.
196
Explain Bacterial Transformation
The change in phenotype and genotype of a bacteria by acquisition of genetic material.
197
Explain everything about Avery’s Experiment.
They wanted to know if the transformation factor was consisted of protein, RNA, or DNA. He removed the carbs and lipids, thus isolating the protein, RNA, and DNA. He then mixed it with the R-bacteria and injected it into the mice. He found that with the elimination of DNA, the mice survived.
198
Explain everything about Chargaff’s Experiment.
Found that DNA is composed of deoxyribose-phosphate- and 4 nitrogenous bases. He then analyzed DNA from many different eukaryotic cells and found that the % and order of the nitrogenous bases varied within the species. A and T were always together and C and G were always bonded together.
199
Explain everything about Hershey and Chase’s Experiment.
The DNA of the virus was injected into the bacteria during infection, leaving the protein outed (coated with radioactive sulfur).
The injected DNA provides genetic information that makes the bacteria produce new viral DNA and protein which assemble into new viruses (DNA coated with radioactive phosphorus).
200
What is PET?
An imaging technique that reveals how tissues and organs are functioning; the tracer collects in areas of the body where chemical activity is high, which often correspond to the areas of diseases.
201
What is RNA composed of?
Ribose-Phosphate-Adenine-Uracil-Cytosine-Guanine
202
What is the difference between ribose and deoxyribose?
Deoxyribose has one LESS hydroxyl group.
203
How many rings do purines have and what nitrogenous bases fall under it?
2-A-G
204
How many rings do pyrimidines have and what nitrogenous bases fall under it?
1-C-T-U
205
Phosphate groups are linked to the _____ carbon of the sugar.
5’
206
What bonds are present in the sugar phosphate backbone?
Phosphodiester Bonds
207
What did Watson and Crick infer from Franklin’s data?
DNA was a double helix; 2nm space in the diameter..
The bases in the DNA were separated by 0.34nm. The helix makes one full turn every 3.4nm. There were the base pairs per turn. Inferred that the sugar phosphate backbone faced the outside of the helix.
208
For the measurements to be appropriate, there had to be a combination of _____ and _____.
1 Purine and 1 Pyrimidine
209
Is the double helix polar?
Yes
210
Watson and Crick proposed a _____ model when it came to the structure of the DNA.
Semi-Conservative; this means that each chain that separated would serve as a template for the formation of a new chain.
211
What were the proposed models for DNA Replication?
Conservative- Semi Conservative- Dispersive
212
What is meant by semi-conservative replication?
The two strands of the original helix separate, and each strand functions as the temperature for the synthesis of a new complementary strand; half is conserved.
213
What is meant by conservative replication?
The original double helix get back together replication, therefore the new one lacks any of the old one; full conservation of one helix.
214
What is meant by dispersive replication?
The two strands of the original double helix separate, and each strand of both daughter molecules contains a mixture of old and newly synthesized parts; old and new mixture.
215
What did Meselson and Stahl use for their experiment?
14 N and 15N.
216
Meselson and Stahl analyzed the DNA extracted from the bacteria in terms of _____.
Weight
217
One round of bacterial takes _____.
20 minss
218
What are the mechanisms of DNA replication?
Unwinding of the DNA strands- Initiation of Replication- Elongation of the DNA Strands being replicated- Termination of Replication.
219
Origins of replication are associated with a _____.
Bubble
220
Each replication bubble has ______ replication forks.
2
221
Which order of strands are continuous?
From the origin of replication, 3’ to 5’ strands are continuous.
222
Define Helicases
Enzymes that untwist the double helix at the replication forks, separating the 2 strands and making them available as templates.
223
Which enzyme is responsible for releasing the tension in DNA strands?
Topoisomerase
224
Define Topoisomerase
An enzymes that breaks, swivels, and rejoins the DNA strands. During the replication of DNA, this enzyme helps relieve the strain in the double helix ahead of the replication fork.
225
Define Single Strand Binding Proteins
Proteins that bind to the unpaired DNA strands during replication, stabilizing them and holding them apart while they serve as templates for the synthesis of complementary DNA strands.
226
Define Primase
An RNA Polymerase that joins RNA nucleotides to make the primer using parental DNA strands as a template.
227
Define DNA Polymerase III
A complex of enzymes that catalyzes the elongation of new DNA by adding nucleotides to the 3’ end of an existing chain. It elongates in the 5’ to 3’ direction and READS in the 3’ to 5’ direction.
228
What is an important thing to note about DNA Polymerase III?
It can only add nucleotides to the 3’ end of a sequence and CANNOT do it by itself. It needs the Primase enzyme to add a sequence of nucleotides.
229
The _____ end has to en free to allow for further binding.
3’
230
What is the bond formed between the carbon ends and the phosphate groups of another nucleotide?
Phosphodiester Bond
231
What happens to the phosphate group when DNA Polymerase allows for the binding of nucleotides?
2 inorganic phosphates get released in the cytoplasm and the nuclear matrix.
232
_____ must be removed; this is done by _____.
Primers- DNA Polymerase I
233
Define DNA Polymerase I
An enzyme that removes and replaces the RNA primer.
234
Define Ligase
An enzyme that ligates the ends of DNA molecules.
235
What is the main difference between leading DNA strands and lagging strands?
The main difference is that the leading strand is continuous and the lagging strand is in Okazaki FRAGMENTS.
236
Define Okazaki Fragments
Short sections of DNA. Formed at the time of discontinuous synthesis of the lagging strand during replication of DNA.
237
What is meant by the proofreading activity of DNA Polymerase?
Polymerase has the ability to check each nucleotide against the template soon after it is added to the growing strand. In real life, we find 1 in 10 million mistakes.
238
How do mismatched nucleotide evade DNA Polymerase proofreading?
They evade proofreading or occur after DNA replication because of the exposure of cells to things such as chemical carinogens and UV light.
239
How is the mismatched nucleotide problem fixed?
Thymine dimer distorts the DNA molecule.
A nuclease enzyme cuts the damaged DNA strand at two points.
DNA polymerase fills the gap.
DNA ligase seals the remaining nick.
240
How many enzymes aid in the fixing of nucleotide mismatching? What is a defect in these enzymes associated with?
We have about 130 enzymes. Defects of one of these enzymes is associated with colon cancer.
241
What happens in the process of chromatin packing?
Proteins called histones allow for the wrapping of strands to make nucleosome beads. The beads pack together. The domains further loop and get more and more condensed.
242
Which histones are available to us? Which histones do the nucleosome contain?
H1,H2A,H2B,H3,H4 are available to us.
H2A,H2B,H3,H4 are contained in the nucleosome (2 of each)
243
Which histone is not present in the octamer? Where is it located?
H1; it is attached near the nucleosome.
244
What are histone modifications?
Methylation of Histones leads to the condensation of DNA and PREVENTS transcription of genes.
Acetylation of HIstones leads to the decondensation of DNA and ALLOWS for the transcription of genes.
245
What is the basic idea of the Central Dogma?
DNA to mRNA is transcription and mRNA to proteins is translation.
246
Why do we need mRNA between DNA and protein?
Because one mRNA molecule can make many proteins thereby amplifying the process. Few mRNAs can translate many proteins.
247
What is the Beadle and Tatum gene theory?
They believed that genes would only code for enzymes. It was later discovered that many proteins are not enzymes. So, this theory became the one gene one protein theory. THE RIGHT VERSION IS ONE GENE ONE POLYPEPTIDE.
248
What does it mean that transcription and translation are coupled?
Transcribed mRNA begins to translate into a polypeptide while still being transcribed.
249
Which key enzyme is involved in transcription?
RNA Polymerase II
250
What are polyribosomes?
Multiple ribosomes
251
Where does transcription occur in prokaryotes and where does it occur in eukaryotes?
In prokaryotes, transcription happens inside of the cell itself and in eukaryotes, transcription happens inside of the cytosol.
252
What is the initial transcript of DNA called?
Heterogenous Nuclear RNA (hnRNA) or pre-mRNA or primary transcript.
253
What does the primary transcript of DNA contain?
Introns and exons; introns are then spliced in the spliceosome.
254
What is a transcription unit?
A transcription unit is a portion of the gene which consists of a start sequence and a termination sequence.
255
How many genes does one transcript unit have in eukaryotes and prokaryotes?
1 in eukaryotes and many in prokaryotes.
256
What are the present stages in transcription?
Binding of RNA Polymerase II- Unwinding of the DNA- Initiation- Elongation- Termination
257
Define Promoter
Promoter is the binding region for RNA Polymerase II; once the Polymerase binds to the promoter, transcription begins.
258
Which strand is called the template strand in transcription?
The strand that contains RNA Polymerase II is called the template strand.
259
In what direction is DNA read in transcription?
3’ to 5’.
260
Does RNA Polymerase II have proofreading activity?
No, it does not.
261
What are the detailed steps that occur in transcription? (In prokaryotic cells)
RNA polymerase II elongates the DNA much like DNA polymerase III but uses RIBONUCLEOTIDES instead of deoxyribonucleotides. Only one strand is transcribed at a time. The RNA polymerase II untwists one turn of the double helix DNA at the time and the terminator sequence in prokaryotes signal the end of transcription.
262
In eukaryotic cells, RNA polymerase II needs the help of other proteins called _____ to find the promoter region.
Transcription Factors
263
Define Transcription Factors
Proteins that recognize the sequence of nucleotides next to the promoter sequence.
264
What happens in transcription ind teal for eukaryotic cells?
The promoter region extends significantly upstream of the TATA box and contains a number of sequences that bind proteins called transcription factors and activator proteins.
265
Is hnRNA larger than mRNA??
Yes, it is; it contains both introns and exons.
266
What are the modifications done to pre-mRNA?
The 5’ guanine cap is added and the 3’ poly A tail is added in the nucleus.
267
RNA splicing can occur in the ______; this is the location of the spliceosome.
Nucleus
268
What is the spliceosome consisted of and what does it do?
It it consisted of snRNPs and other proteins which come together in the spliceosome and get rid of the present introns in the pre-mRNA.
269
Each _____ corresponds to the appropriate exon.
Domain
270
What does it mean for adults to have sticky domains?
The exons that code for the domains are sticky, not allowing for the movement of genes. In embryos, however, the embryonic fibronectin is not sticky, allowing for the movement of genes.
271
What is the role of the 5’ cap added to the mRNA.
It protects the mRNA from degradation and guides it to the ribosome for protein synthesis.
272
What is the role of the Poly A tail?
It protects the mRNA form degradation and it guides it through the nucleopores to the cytosol.
273
Is transcription followed by translation immediately in eukaryotes or prokaryotes?
Prokaryotes
274
How many different amino acid combinations do us humans have?
64
275
What does it mean for the genetic code to be redundant but no ambiguous?
Codons are similar but no one codon can code for multiple amino acids.
276
What is the firefly protein called?
Luciferase
277
What is the start codon and what is it called?
AUG- Methionine
278
What are the stop codons?
UAG-UGA-UAA
279
What enzyme is responsible for the addition of the 5’ cap to the mRNA?
Guanyl Tranferase.
280
Which enzyme is responsible for the addition of a poly A tail?
Poly A Polymerase
281
What is the ribosome composed of?
2 subunits; the alpha and the beta subunit.
282
Where is the ribosome made and where is it transferred to?
It is made in the nucleolus and transferred into the cytosol.
283
What is the job of tRNA and what is its structure?
Its job is to transfer amino acids to the ribosome and the amino acid attachment site is at the 3’ end.
284
How many different tRNAs do we have?
45.
285
What does the wobble property mean?
The bonding that occurs in tRNA is not as strict and some wobbly bonds can be formed.
286
What does it mean for the genetic code to be degenerate?
The first two bases of the codon that code for the same amino acid are the same but the third one differs.
287
What is the job of the aminoacyl-tRNA synthetase?
Its job is to join the amino acid to a tRNA.
288
How does aminoacyl-tRNA synthetase do its job?
Amino acid and ATP come into the enzyme; for the binding of the amino acid, energy from ATP is needed. Two phosphates get released, leaving AMP attached to the amino acid. From there, the tRNA binds to the enzyme and the AMP is released. Now, the amino acid binds to the tRNA. And the activated amino acid is released.
289
What are the sites on the ribosome and on which subunit are they located on?
E,P,A (located on the large subunit). E= Exit Site.
P= peptidyl-tRNA binding site; A= aminoacyl-trna binding site.
290
On which subunit is the mRNA binding site located on?
The small subunit.
291
mRNA is read from the _____ direction.
5’ to 3’.
292
What happens in translation specifically?
The process is initiated when an tRNA with AUG binds to the small ribosomal subunit. The energy from GTP is used to allow for the brining in of the large ribosomal subunit. The tRNA then sits on the P site of the amino acid. A new tRNA comes into the A site, and peptide bonds are formed in between the amino acids of the A site and the P site. The energy used again from GTP allows for the movement of one tRNA to the E site. Lastly, a release factor binds to the A site of the ribosome, leading to the release of the tRNA and the growing chain of amino acids. The ribosomal submits are broken apart as well.
293
What is the difference between the ribosomes of eukaryotes and prokaryote?
Prokaryotes have smaller and slightly different ribosomes than eukaryotes; these difference are used to develop antibiotics that perturb translation in prokaryotes but not in eukaryotes.
294
Where are proteins made and where do they end up going?
They are made in the cytosol; they either stay in the cytosol or go to the ER.
295
What are the two types of ribosomes?
Bound ribosomes (attached to the ROUGH ER)
Free ribosomes (in the cytosol).
296
The proteins that go from the ER to the golgi come out in vesicles that are:
Secreted: they fuse with the plasma membrane and release the proteins to the outside of the cell or fuse with the membrane and remain in the membrane.
Stay in the cell: are delivered to organelles or to the plasma membrane).
297
How does targeting proteins to the ER work?
The polypeptide on the ribosome has a portion called the signal polypeptide. The signal-recognition particles binds to the signal peptide, bringing it to the SRP Receptor protein. From there, the polypeptide get is released into the ER.
298
What are naturally occurring mutations?
They are spontaneous mutations that can results in errors in replication or repair or recombination.
299
Errors in replication or repair include?
The failing of DNA Polymerase III to proofread.
300
Errors in recombination include?
Occurrences during crossing over.
301
What are silent mutations?
Have no effect on the amino acid being produced by the codon due to the redundancy of the genetic code.
302
What are Missense mutations?
Still code for an amino acid, but not for the right one. Called a non synonymous mutation.
303
What is a nonsense mutation?
Can change an amino acid codon into a stop codon, nearly always leads to a nunfunctional protein.
304
What do indels lead to?
Frameshift mutations.
305
What are the theories generated regarding heredity?
Blending and Particulate
306
What did Aristotle believe regarding heredity?
He believed that particles called pan genes came together to form the sperm and the egg.
307
What did Leeuwenhoek believe?
He believed that the sperm was the driving force behind inheritance (the inheritance primarily came from sperm).
308
What did de Graff believe?
He believed that heredity primarily came from the egg (the egg was the driving force behind heredity).
309
What did the blending theory of heredity suggest?
It suggested that the mixture of parents provide an intermediate heritability of traits.
310
What did the particulate theory of heredity state and who was the pioneer.
It stated that the transmittance of discrete heritable factors remain separate from one generation to the next.
311
What did Mendel use?
He used true breeding varieties.
312
What are true-breeding varieties?
A variety that when it self-pollinates the offspring are the same a the parents, generation after generation.
313
Each gene in a diploid organism is represented by two _____.
Alleles
314
Define allele.
A variant of a gene.
315
Define Locus
Specific location on the chromosome that contains an allele.
316
Define character.
Inheritable features (genes).
317
Define Trait
Variant of character (allele).
318
What is a mono hybrid cross?
A cross between parental varieties thar differ in one gene; the law of segregation was deducted by this.
319
What is genotype?
An organism’s genetic makeup.
320
What is phenotype?
An organisms observable physical characteristics.
321
Define Homozygous.
Having two identical alleles for a given gene.
322
Define heterozygous.
Having two different alleles for a given gene.
323
Define Dominant Allele
The allele that is fully expressed in the phenotype of a heterozygous organism.
324
Define Recessive Allele
The allele that is completely masked in the phenotype of an organism.
325
_____ account for the variations in the inherited characteristics.
Alleles
326
The two alleles are inherited one from each ______.
Parent
327
What does the law of segregation of alleles mean?
The two alleles present in the two homologous chromosomes will segregate into different gametes. Random paring will happen.
328
What is a testcross?
A cross between an organism with a dominant phenotype but an unknown genotype with an organism that is homozygous recessive.
329
What is incomplete dominance?
Neither of one the alleles is dominant; the results obtained doesn’t rely on the presence of one allele.
330
Define Dihybrid Cross
A cross between two parental varieties that differ by two genes.
331
What is the law of independent assortment?
Each pairs of the alleys assorts independently in the gametes because the non-homologous chromosomes assort themselves independently during meiosis I.
332
What are the levels of biological organization?
Biosphere-Ecosystem-Community-Population-Organsm. BECPO
333
Define Biosphere
The entire population of earth inhabited by life.
334
Define Ecosysten
All the organisms in a given area as well as the abiotic factors with which they interact; one or more communities with the physical environment around them.
335
Define Community
All the organisms that inhabit a particular area; an assemblage of populations of different species living close enough together for potential interaction.
336
Define Population
A group of individuals of the same species that live in the same area and interbreed, producing fertile offspring.
337
Define Organism
An individual living thing; consisting of one or more cells.
338
Define Organ
A specialized center of body function composed of several different types of tissues.
339
Define Tissues
An integrated group of cells with similar structure, function, or both.
340
Define Cell
Life’s fundamental unit of structure and function; the smallest unit of organization that can perform all activities required for life.
341
Define Organelle
Any of several membrane-enclosed structure with specialized functions, suspended in the cytoskeleton of eukaryotic cells.
342
Define Molecule
Two or more atom held together by covalent bonds.
343
What is the rest of the biological system consisted of?
Organ-Tissues-Cells-Organelle-Molecule OTCOM
344
Define Emergent Properties
New properties that arise with each step upward in the hierarchy of life, owing to the arrangement and interaction of parts as complexity increases.
345
What are the different types of cells?
Prokaryotic and Eukaryotic
346
What group of singe-called microorganisms are prokaryotic?
Bacteria-Archaea
347
Define Eukaryotic Cell
A type of cell with a membrane-enclosed nucleus and membrane enclosed organelles. Organisms with eukaryotic cells. (Plants, fungi, animals, protists).
348
Define Prokaryotic Cell
A cell lacking a nucleus or other membrane-bound organelles. Furthermore, prokaryotic cells are generally smaller than eukaryotic cells.
349
Define DNA (deoxyibonucleic acid).
A nucleic acid molecule, usually a double stranded helix, in which polynucleotide strands consist of nucleotide monomers with a deoxyribose sugar and nitrogenous bases adenine, guanine, cytosine, and thymine; capable of being replicated and determine the inherited structure of the proteins of cells.
350
Define Genes
A discrete unit off heredity information consisting of a specific nucleotide sequences in DNA.
351
Each chromosome contains one very long DNA molecule with hundreds of thousands of _____, each a section of the DNA of the chromosome.
Genes
352
Define Gene Expression
The process by which information encoded in the DNA directs the synthesis of proteins, or, in some cases, RNA that are not translated into proteins and instead function as RNAs.
353
Define Genome
The genetic material of an organism.
354
Define Proteome
The entire sets of proteins expressed by a cell or a tissue.
355
Define Producers
Organisms that produces organic compounds from CO2 by harnessing light energy (in photosynthesis) or by oxidizing inorganic compounds.
356
Define Consumers
An organism that feeds on producers, other consumers, or non-living organic materia.
357
Define Feedback Regulation
The regulation of a process by its output or end result.
358
Define Evolution
Descent with modification.
359
What are the three domains named by biologists?
Bacteria-Archaea-Eukarya
360
What are the divisions of domains called?
Kingdoms.
361
What are the kingdoms present in the Eukarya domain?
Protists-Animals-Fungi-Plants
362
Define Inductive Reasoning
A type of logic in which generalizations are made based on a large number of specific observations.
363
Define Deductive Reasoning
A type of logic in which results are predicted from a general premise.
364
Define Matter
Anything that has mass and takes up space.
365
Matter is made of _____.
Elements
366
Define Element
Any substance that cannot be broken down to an other substance by chemical reactions.
367
Define Compound
A substance containing two or more different elements in a fixed ratio.
368
Of the natural 92 elements, _____ are essential.
20-25%
369
Define Essential Elements
A chemical element required for an organism to survive, grow, and reproduce.
370
How many elements do humans need an how many elements do plants need?
Humans: 25
Plants: 17
371
What are the 4 elements that make up 96% of the living mattter.
Carbon-Oxygen-Hydrogen-Nitrogen. CHON
372
Define Trace Elements
An element necessary for life but required in extremely minute amounts.
373
What is an example of a trace element?
Iron
374
What is caused by a deficiency in iodine?
It causes the thyroid grain to grow to an abnormal size; called goiter.
375
What is an example of a naturally occurring element that is toxic to humans?
Arsenic
376
What is an example of a community that has adapted to an environment contain toxic elements?
Serpentine Plant Community
377
Define ATOM
The smallest unit of matter that retains the properties of an element.
378
What are the three kinds of subatomic particles?
Protons-Neutrons-Electrons
379
Define Neutron
A nerve cell; its the fundamental unit of the nervous system, having structure and properties that allow it to conduct signals by taking advantage of the electrical charge across it plasma membrane.
380
Define Proton
A subatomic particle with a single positive electrical charge. Found in the nucleus of an atom.
381
Define Electron
A subatomic particle with a negative charge and a mass of about 1/2000 of a neutron or a proton.
382
Define Atomic Nucleus
An atom’s central dense core, containing protons and neutrons.
383
Define Atomic Number
The number of protons in the nucleus of an atom.
384
Define Mass Number
The total number of protons and neutrons in a cell.
385
Define Isotope
One of several atomic forms of an element, each with the same number of protons but with a different number of neutrons, thus different in atomic mass.
386
Do isotopes behave identically in chemical reactions?
Yes
387
Define Radioactive Isotope.
An isotope that is unstable and decays spontaneously.
388
Which of the subatomic particles are involved in chemical reactions?
Electrons
389
Define Energy
The capacity to cause change, especially to do work.
390
The more distant an electron is from the nucleus, the _____ its potential energy.
GREATER
391
Define Electron Shells
An energy level of electrons at a characteristic average distance from the nucleus of an atom.
392
How many electrons can each shell hold (going from the closest shell to the farthest)?
2,8,8
393
Define Valence Electrons
An electron in the outermost shell.
394
Define Valence Shell
The outermost energy shell of an atom, contains the valence shell electrons involved in the chemical reactions of an atom.
395
Can atoms filled with electron shells partake in chemical reactions?
No, they are Inter.
396
Define Orbital.
The 3D space where an electron is found 90% of the time.
397
Define Covalent Bonds
A type of strong chemical bond in which two atoms are one or more pairs of valence electrons.
398
Define Valence
The bonding capacity of the given atom; the number of covalent bonds it can form, which usually equals the numbers of unpaired electrons in its outermost shell.
399
Define Non-Polar Covalent bond.
A type of covalent bond where electrons are being shared equally between two atoms of similar Electronegativity.
400
Define Polar-Covalent Bond.
A covalent bond between atoms that differ in Electronegativity. The shared electrons are pulled closer to the more electronegative atom, making it slightly less negative and the other atom slightly more positive.
401
Define Ions
An atom or a group of atoms that has gained or lost one or more electrons.
402
Define Cation
A positively charged ion.
403
Define Anion
A negatively charged ion.
404
Does an ionic compound consist of molecules?
No
405
Define Hydrogen Bond
A type of weak chemical bond formed when the slightly positive hydrogen atom of a polar covalent bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule or in another region of the same molecule.
406
Define van der Waals Interactions
Weak attractions between molecules or parts of molecules that result from transient local charges.
407
Define Reactants
A starting material in the chemical reaction.
408
Define Product
A material resulting from a chemical reaction.
409
Are atoms destroyed/created in a chemical reaction or re-arranged?
Re-arranged.
410
Define Chemical Equilibrium
In a chemical reaction, the state in which the rate of the forward reaction equals the rate of the reverse reaction, so that the relative concentrations of the reactants and products do not change with time.
411
What is the most abundant element?
CARBON
412
What are the maximum number of electron shells that an atom can have?
3.
413
How many electrons can each orbit hold?
2
414
Are H-bond present in DNA?
Yes
415
Define Polar Covalent Bonds
A covalent bond between atoms that differ in Electronegativity. The shared electrons are pulled closer to the more electronegative atom, making it slightly negative and the other slightly positive.
416
Are hydrogen bonds fragile when water is in its liquid form?
Yes
417
What is a typical behavior exhibited by hydrogen bonds?
They break and re-form with high frequency.
418
Define Cohesion
The linking of like molecules, often done by hydrogen bonds.
419
How does water move against gravity inside of plants?
Cohesion due to the hydrogen bonding contributes to the transport of water and dissolved nutrients against the gravity of plants. Water from the roots reaches the leaves through a network of water-conducting cells.
420
Define Adhesion
The clinging of one substance to another, such as water to plant cells by means of hydrogen bonds.
421
What is related to Cohesion?
Surface Tension
422
Define Surface Tension
The measure of how difficult it is to break the surface of a liquid,. Water has high surface tension because of the hydrogen bonds of surface molecules.
423
Define KE
The energy associated with the random motion of objects. Moving matter can perform work by imparting motion to another matter.
424
Define Thermal Energy
KE due to the random motions of molecules and atoms.
425
Is thermal energy the same thing as temperature?
No
426
Does a pot of coffee have more thermal energy or a swimming pool? Why?
A swimming pool.
Although the pot of coffee has a much higher temperature than the water in a swimming pool, the swimming pool contains more thermal energy due to its volume.
427
Define Heat
The transfer of thermal energy from one body of mass to another.
428
Define Calorie
The amount of heat energy required to heat 1 gram of water by 1 degree Celsius.
429
Define Kilocalorie
The amount of heat needed to heat 1kg of water by 1 degree Celsius.
430
Define Specific Heat
The amount of heat that must be absorbed or lost for 1g of a substance to change its temperature by 1 degree Celsius.
431
Define Evaporative Cooling
The process in which the surface of an object becomes cooler during evaporation, a result of molecules with the greatest kinetic energy changing from the liquid to the gaseous state.
432
At what temperature does water reach its greatest density?
4
433
Define Solution
A liquid that is a homogenous mixture of two or more substances.
434
Define Solvent
The dissolving agent of a solution. Water is the most versatile solvent.
435
Define Solute
A substance that is dissolved in the solution.
436
Define Hydration shell
The sphere of water molecules around a dissolved ion.
437
Define Hydrophilic
Having attraction for water.
438
Define Hydrophobic
Having no affinity for water; tending to coalesce and form droplets.
439
What is the concentration of hydrogen and hydroxide ions in pure water?
10^-7M
440
Define Acid
A substance that increases the hydrogen ion concentration of a solution.
441
Define Base
A substance that decreases the hydrogen ion concentration in a solution.
442
Define pH
A measure of hydrogen ion concentration equal to -log (H+) and ranging in value from 0 to 14.
443
What is the equation for the product of hydrogen and hydroxide concentrations?
[H+][OH-]=10^-14
444
What happens to the pH as the concentration of the hydrogen ion increases?
It goes down.
445
What do the pH ranges indicate?
Lower than 7 means it’s acidic.
7 means its neutral.
Higher than 7 means that it’s basic.
446
Define Buffer
A solution that contains a weak acid and its corresponding base. A buffer minimizes the change in pH when acids or bases are added to the solution.
447
Define Ocean Acidification.
The process by which the pH of the ocean is lowered (made more acidic) when excess CO2 dissolves in seawater and forms carbonic acid.
448
Define the Process of Ocean Acidification
As seawater acidifies, the extra hydrogen ions combine with the carbonate ion to form bicarbonate ions, thereby reducing the carbonate ion concentration. The decrease in carbonate ion concentration is significant because the ions are required for calcification, the production of calcium carbonate by many marine organisms.
449
What are the 4 emergent properties of water that contribute to Earth’s sustainability for life?
Cohesive/Adhesive Properties-Ability to Moderate Temperature-Expansion Upon Freezing-Versatility as a Solvent. CTES
450
What is the acronym for cohesion and adhesion?
CI-AO. Cohesion-Itself; Adhesion-Other
451
How does a Carbon atom complete its valence shell?
By sharing its 4 electrons with other atoms so that 8 electrons are present.
452
What are the most frequent bonding partners for carbon?
H,O,N
453
Define Hydrocarbons
An organic molecule composed of only hydrogen and carbon.
454
What are 4 ways that the carbon skeleton can vary?
Length-Branching-Presence of a Double Bond-Presence of Rings. LBDR
455
What is a characteristic of hydrocarbons?
They can undergo reactions that release a relatively large amount of energy.
456
What do fat molecules consist of?
They consist of a small, non hydrocarbon component joined to three hydrocarbon tails that account for the hydrophobic behavior of fasts.
457
Define Isomers
One of two or more compounds that have the same numbers of atoms of the same elements but different structures and hence different properties.
458
What are the 3 types of isomers?
Structural-Cis/Trans-Enantiomers
459
Define Structural Isomers
One of two or more compounds that have the same molecular formula but differ in the covalent arrangements of their atoms. They may have a different location of double bonds.
460
Define Cis/Trans Isomer
One of several compounds that have the same molecular formula and covalent bonds between atoms but differ in location of double bonds.
461
Define Cis Isomer
The two X’s are on the same side. CS (Cis-Same)
462
Define Trans Isomer
The two X’s are on the opposite sides.
463
Define Enantiomer
One of two compounds that are mirror images of each other and that differ in shape due to the presence of an asymmetric carbon.
464
Define Functional Groups
A specific configuration of atoms commonly attached to the carbon skeleton of organic molecules and involved in chemical reactions.
465
What are the 7 chemical groups?
HCCA-SPM. Hydroxyl-Carboxyl-Carbonyl-Amino-Sulfhydryl-Phosphate-Methyl
466
Explain everything about the Hydroxyl group.
Is polar due to the presence of an electronegative oxygen. Forms hydrogen bonds with water, helping dissolve compounds such as sugars.
An example is ethanol. HE
The hydroxyl group is a single bound coming out of it. (-OH)
467
Explain everything about the Carbonyl Group
Sugars with ketones are called ketoses; those with aldehydes are called aldoses.
An example is Acetone. CA
Carbonyl is a carbon double bonded to an O with two single bonds combing out of the carbon.
468
Explain everything about the carboxyl group.
Acts as an acid (can donate H+) because the covalent bond between the oxygen and hydrogen is is so polar.
An example is acetic acid. CA
Carboxyl is COOH. A carbon double bonded to an O with a single OH bond coming out of the carbon. One of the bonds is empty.
469
Explain everything about the Amino Group
Acts as a base; can accept H+ from the surrounding solution.
An example is glycine. AG
An amino group is NH2. N has 3 bonds coming out of it, 2 being bonded to H
470
Explain everything about the Sulfhydryl Group
Two S-H groups can react, forming a cross-link that helps stabilizes proteins structures.
An example includes Cysteine. SC
Sulfhydryl group is a SH with a single bonding coming out of it.
471
Explain everything about the phosphate group?
Contributes negative charges.
An example includes Glycerol Phosphate. GP
The phosphate group is OPO32-; the P is double bonded to one O, with single bonds to the other O’s.
472
Explain everything about the methyl group.
Affects the expression of genes when on DNA or proteins bound to the DNA.
An example includes 5-Methylcytosine.
The methyl group is CH3. Carbon is single bonded to 3 different hydrogens, with another single bond coming out of it.
473
Define ATP
An adenine containing nucleoside triphosphate that releases free energy when its bonds are hydrolyzed.
474
Define Asymmetric Carbon
A carbon with an organic compound that contains 4 different atoms or groups of atoms.
475
Can carbons with a double bond or a triple bond ever be asymmetric?
No, because they have three and two bonds respectively.
476
How can you tell if a carbon is asymmetric?
If there’s 4 different groups bonded to it, then it’s asymmetric. When we’re analyzing a carbon and looking at the groups, the groups include everything in the respective directions we’re looking at.
477
Which of the functional groups are hydrophobic?
Methyl
478
What are the 4 major classes that molecules can be put in?
Carbs-Lipids-Proteins-Nucleic Acids. CLPA
479
Define Macromolecules
A giant molecule formed by the joining of smaller molecules, usually by a dehydration reaction.
480
What does dehydrogenase do in the body?
It breaks down alcohol.
481
Macromolecules are _____ built from _____.
Polymers-Monomers
482
Define Polymer
A long molecule consisting of many similar or identical monomers linked together by covalent bonds.
483
Define Monomers
The subunit that serves as the building blocks for polymers.
484
Define Enzymes
A macromolecule that serves as a catalyst; a chemical agent that increases the rate of reaction without being consumed by the reaction. Most enzymes are proteins.
485
Define Dehydration Reaction
A chemical reaction in which two molecules become covalent bonded together with the removal of a water molecule. (DEHYDRATION-JOINED)
486
How are polymers disassembled to monomers?
Through hydrolysis.
487
Define Hydrolysis
A chemical reaction that breaks bonds between two molecules by the addition of water; functions in the disassembly of polymers.
488
What is an example of hydrolysis in our bodies?
Digestion
489
_____ serve as fuel and building material.
Carbs
490
Define Carbohydrates
A sugar (monosaccharide) or one of its dimers (disaccharides).
491
Define Monosaccharides
The simplest carbohydrate, active alone or serving as the monomer for disaccharides and polysaccharides. Also called simple sights, monosaccharides have molecular formulas that generally some multiple of CH2O.
492
What is the most common monosaccharide?
Glucose C6H12O6
493
How are ketoses and aldoses distinguished structurally?
It depends on the location of the carbonyl group.
494
What is the range for the size of carbon rings in sugars?
3-7
495
What is an asymmetric carbon?
A carbon that is bonded to 4 different groups.
496
For aldehyde groups, where are the carbonyl groups located?
At the end of the carbon skeleton. AE
497
For ketones, where are the carbonyl groups located?
Within the carbon skeleton. KW
498
What is the formula for Trioses and what are two examples?
C3H6O3; glyceraldehyde and dihydroxyaceotne
499
What is the formula for Pentoses and what are some examples?
C510O5; ribose and ribulose.
500
What is the formula for Hexoses and what are some examples?
C6H12O6; glucose, fructose.
501
In ring structures, what does each unlabeled corner represent?
Carbon
502
What does the thicker edge of the ring indicate?
That you’re looking at the ring edge-on. The components attached to the ring lie above or below the plane of the ring.
503
Define Disaccharide
A double sugar, consisting of two monosaccharides joined by a glycosidic linkage formed by a dehydration reaction.
504
Define Glycosidic Linkage
A covalent bond formed between two monosaccharides by a dehydration reaction.
505
What is the most prevalent disaccharide?
Sucrose
506
Define Polysaccharides
A polymer of many monosaccharides, formed by dehydration reactions.
507
What are some functions of polysaccharides?
Serve as storage material- Building material for structures that protect the cell or the whole organism. SP
508
Define Starch
A storage polysaccharide in plants, consisting of entirely glucose monomers joined by glycosidic linkages.
509
Define Glycogen
An extensive branched glucose storage polysaccharide found in the liver and muscle of animals; the animal equivalent of starch.
510
Define Cellulose
A structural polysaccharide in plant cell walls, consisting of glucose monomers joined by beta glycosidic linkages.
511
What is the most abundant organic compound in the world?
Cellulsoe
512
What are the ways that the hydroxyl group can be arranged in glucose rings?
The hydroxyl group attached to the number one carbon is either below or above the plane of the ring: these two rings are called alpha and beta. If it’s below, it’s alpha; if it’s above, it’s beta.
513
How is cellulose referred to in food packages?
Insoluble Fiber
514
Define Lipids
Any of a group of large biological macromolecules which contain fats, phospholipids, and steroids, that mix poorly, if at all, with water. FPS
515
What is one important shared trait between lipids?
They mix poorly, if at all, with water.
516
What do lipids consist of chemically?
Hydrocarbons
517
Define Fat
A lipid consisting of three fatty acids linked to one glycerol molecule; also called a triacylglycerol
518
What is glycerol?
It’s an alcohol; each of its 3 carbons bears a hydroxyl group.
519
Define Fatty Acid
A Carboxyllic acid with a long carbon chain. Fatty acids vary in length and in the number and location of double bonds; three fatty acids linked to one glycerol molecule.
520
What is an ester linkage?
A bond formed by the dehydration reaction between a hydroxyl group and a Carboxyl group. EHC
521
Define Saturated Fatty Acids
A fatty acid in which all the carbons in the hydrocarbon tail are connected; no presence of double bonds.
522
Define Unsaturated Fatty Acids
A fatty acid that has one or more double bonds in the hydrocarbon tail. Such bonding reduces the number of hydrogen atoms attached to the carbon skeleton.
523
What are some differences between saturated and unsaturated fats?
For saturated fats, at room temperature, the molecules are packed together closely, forming a solid.
For unsaturated fats, the molecules cannot pack together closely enough to solidify becase of the kinks in some of their fatty acid hydrocarbon chains.
524
Define Trans Fats
An unsaturated fat, formed artificially during the hydrogenation of oils, containing one or more trans double bonds.
525
Define Phospholipid
A lipid made up of glycerol linked to two fatty acids and a phosphate group. The hydrocarbon chains of the fatty acids act as non polar, hydrophobic tails while the rest of the molecule acts as a polar, hydrophilic head. Phospholipids form i layers that function as biological membranes.
526
How are phospholipids arranged in a bilayer?
The hydrophilic heads are facing outwards, while the hydrophobic tails are facing inwards.
527
Define Steroids
Any type of lipid characterized by a carbon skeleton consisting of four fused rings with various chemical groups attached.
528
Define Cholesterol
A steroid that forms an essential component of animal cell membranes and acts as a precursor molecule for the synthesis of other biologically important steroids, such as many hormones.
529
Proteins are constructed from a set of _____ amino acids.
20
530
What is the bond between amino acids called?
Peptide Bond
531
Define Polypeptide
A polymer of many amino acids joined together by peptide bonds.
532
Define Protein
A biologically functional molecule consisting of one or more polypeptides formed and coiled into a specific 3D structure.
533
Define Amino Acid
An organic molecule possessing both carboxyl and an amino group. They serve as the monomers for polypeptides.
534
What are the 4 different partners of an amino acid?
Carboxyl Group-Amino Group-H-R (Variable Group) ACRH
535
What are the different types of proteins?
Enzymatic-Storage-Hormonal-Contractile-Defensive-Transport-Receptor-Structural
536
Describe everything about enzymatic proteins
Function: selective acceleration of chemical reactions.
Example: Digestive Enzymes ED
537
Describe everything about Storage Proteins
Function: storage of amino acids.
Examples: Casein
538
Explain everything about Hormonal Proteins.
Function: coordination of an organisms activities.
Ex: Insulin
539
Explain everything about Contractile and motor proteins.
Function: movement.
Example: undulations of the cilia and the flagella.
540
Explain everything about defensive proteins.
Function: protection against diseases.
Example: antibodies that inactive and help destroy viruses and bacteria.
541
Explain everything about transport proteins.
Function: transport of substances.
Example: Hemoglobin, the iron-containing protein of vertebrate blood.
542
Explain everything about receptor proteins.
Function: response of cell to chemical stimuli
Example: receptors built into the membrane of a nerve cell.
543
Explain everything about structural proteins.
Function: Support.
Example: keratin.
544
Amino acids have side chains that are generally _____ in charge due to the presence of a Carboxyl group.
Negative
545
What are the superimposed structures that proteins have?
Primary-Secondary-Tertiary-Quaternary. PSTQ
546
Define Primary Structure
The level of protein structure referring to the specific linear sequence of amino acids.
547
Define Secondary Structure
Regions of repetitive coiling or folding of the polypeptide backbone of a protein due to hydrogen bonding being between constituents of the backbone.
548
Define Alpha Helix
A coiled region constituting one form of the secondary structure of proteins, arising from a specific pattern of hydrogen bonding between atoms of the polypeptide backbone.
549
Define Beta Pleated Sheet
One form of the secondary structure of proteins, arising from a specific pattern of hydrogen bonding between atoms of the polypeptide backbone.
550
Define Tertiary Structure
The overall shape of the protein molecule due to interactions of the amino acid side chains, including hydrophobic interactions, hydrogen bonds, ionic bonds, and disulfide bridges.
551
Define Hydrophobic Interactions
A type of weak chemical interaction caused when molecules that do not mix with water coalesce to exclude water.
552
Define Disulfide Bridges
A strong covalent bond formed when the sulfur of one cysteine monomer binds to the sulfur of another cysteine monomer.
553
Define Quaternary Structure
The particular shape of a complex, aggregate protein, defined by the characteristic 3D arrangement of its constituent subunits, each a polypeptide.
554
Define Selective Permeability
A property of biological membranes that allows them to equal treatment the passage of substances across them.
555
What is the most abundant lipid in most membranes?
Phospholipids
556
Define Amphipatic
Having both a hydrophilic and a hydrophobic region.
557
Define Fluid Mosaic Model
The currently accepted model of cell membrane structure, which envisions the membrane as a mosaic of protein molecules drifting laterally in a fluid layer of phospholipids.
558
What is the membrane primarily held together by?
Hydrophobic Interactions
559
Are hydrophobic interactions stronger or weaker than chemical bonds?
Weaker
560
The temperature at which a membrane solidifies depends on the _____ it is made of.
Lipids
561
What is meant by the fluidity of the membrane?
Membranes are not static sheets of molecules locked rigidly in place.
562
What happens to the fluidity of the membrane with decreasing temperatures?
The fluidity of the membrane decreases.
563
Under what conditions does a membrane continue to keep its fluidity at lower temperatures?
As the temperature decreases, the membrane remains fluid to a lower temperature if it is rich with phospholipids with UNSATURATED carbon tails.
564
How does cholesterol affect the fluidity of the membrane at high temperatures?
Cholesterol makes the membrane less fluid by restraining phospholipid movements. However, because cholesterol also hinders the close packing of phospholipids, it lowers the temperature required for the membrane required to solidify. Thus, it can be thought of as a fluidity buffer.
565
What does the fluidity of the membrane afffect?
The permeability and the ability of the membrane proteins to move to where the function is needed.
566
What are the different types of membrane proteins?
Integral and Peripheral.
567
Define Integral Proteins
A trasnmembrane protein with hydrophobic regions that extend into and often completely span the hydrophobic interior of the membrane and the hydrophilic regions in contact with the aqueous solution on one or both sides of the membrane.
568
Define Peripheral Proteins
A protein loosely bound to the surface of a membrane to part of an integral protein and not embedded in the lipid bilayer.
569
What are some functions of the membrane proteins?
Transport-Enzymatic Activity-Signal Transduction-Cell Cell Recognition-Intercellular Joining-Attachment to the Cytoskeleton-Extracellular Matrix TES-CIE
570
Define Glycolipids
A lipid with one or more covalently attached carbs.
571
Define Glycoproteins
A protein with one or more attached carbs.
572
Are membrane carbs primarily bounded to glycoproteins or glycolipids?
Glycoproteins
573
Can non-polar molecules dissolve quickly across the bilayer?
Yes, he they can cross it easily.
574
Can polar molecules cross the bilayer quickly?
No
575
Define Transport Proteins
A transmembrane protein that helps a certain substance or class of closely related substances cross the membrane.
576
What are a subdivision of transport proteins?
Channel Proteins; they function by having a hydrophilic channel that certain molecules or atomic ions use as a tunnel through the membrane.
577
Define Aquaporins
A channel protein that specifically facilitates osmosis, the diffusion of free water across the membrane.
578
Define Carrier Proteins
One type of transport protein. They hold onto their passengers and change shape in a way that shuttles them across the membrane.
579
_____ is the diffusion of substances across a membrane with no energy investment.
Passive Transport
580
Define Concentration Gradient
A region along which the density of a chemical substance increases or decreases.
581
Each substance diffuses _____ its concentration gradient.
Down
582
Define Tonicity
The ability of a solution surrounding a cell that cause the cell to gain/lose water.
583
Define Isotonic
Referring to a solution that, when surrounding a cell, causes no net movement of water into or out of the cell. Water diffuses across the membrane, but at the same rate in both directions.
584
Define Hypertonic
Referring to a solution that, when surrounding a cell, causes the cell to lose water. HYPER-L
585
Define Hypotonic
Referring to a solution that, when surrounding a cell, will cause the cell to take up water.
586
Define Osmoregulation
Regulations of solute concentrations and water balance by an organism.
587
_____ diffusion is the same thing as passive transport.
Facilitated
588
Define Ion Channels
A transmembrane protein channel that allows a specific ion to diffuse across the membrane down its concentration gradient.
589
Define Gated Channels
A transmembrane protein channel that opens or closes in response to chemical stimuli.
590
In which type of transport protein does a shape change happen?
Carrier
591
In which type of transport protein does a shape change happen?
Carrier Proteins
592
Define Active Transport
The movement of a substance across a cell membrane against its concentration gradient or electrochemical gradient, mediated by specific transport proteins and requiring an expenditure of energy.
593
How can ATP power active transport?
When its terminal phosphate group is transferred directly to the transport protein, the protein can be induced to change its shape in a manner that translocates a solute bound to the protein across the membrane.
594
Define Sodium-Potassium Pump
A transport protein in the plasma membrane of animal calles that actively transports sodium out of the cell and potassium into the cell. SO-PI 3 sodiums out and 2 potassium’s in.
595
Define Membrane Potential
The difference in electrical charge across a cell’s plasma membrane due to the differential distributions of ions.
596
Are both Carrie proteins and channel proteins used in facilitated diffusion?
Yes, they can be used.
597
What are the two forces that can affect diffusion of ions across a membrane?
Electrical-Chemical
598
Define Electrochemical Gradient.
The diffusion gradient of an ion, which is affected by both the concentration differences of an ion across a membrane and the ion’s tendency to move relative to the membrane potential.
599
Define Electrogenic Pump
An active transport protein that generates voltage across a membrane while pumping ions.
600
Define Proton Pump
An active transport protein in a cell that uses ATP to transport hydrogen ions out of a cell against their concentration gradient, generating a membrane potential in the process.
601
_____ across the plasma membrane occur by exocytosis and endocytosis.
Bulk Transport
602
Define Exoocytosis
The cellular secretion of biological molecules by fusion of vesicles containing them within the plasma membrane.
603
Define Endo cytosis
Cellular uptake of biological macromolecules and particulate matter via formation of vesicles from the plasma membrane.
604
What are the different types of Endocytosis?
Phagocytosis (cellular eating)-Pinocytosis (cellular drinking)-Receptor Mediated Endocytosis
605
In phagocytosis, a cell engulfs a particle by extending _____ around it and packing it within a membranous sac called a _____.
Pseudopodia-Food Vacuole
606
Which molecules can easily pass through the bilayer?
Gases, hydrophilic molecules, small polar uncharged molecules.
607
What are some basic features that ALL cells share?
They are all bounded by a plasma membrane-All cells contain chromosomes-All cells have ribosomes.
MCR
608
Define Cytosol
The semi-fluid portion of the cytoplasm.
609
Define Prokaryotic Cell
A type of cell lacking a membrane-enclosed nucleus and membrane-enclosed organelles.
610
What is the major difference between Prokayotes and Eukaryotes?
In eukaryotic cells, most of the DNA is in an organelle called the nucleus, which is bounded by a double membrane. In a prokaryotic cell, the DNA is concentrated in a region that is not membrane-enclosed called the nucleoid.
611
A smaller object has a greater ratio of _____ to _____.
Surface Area-Volume
612
The eukaryotic cell’s giant instructions are housed in the _____ and carried out by the _____.
Nucleus-Ribosome
613
Define Nucleus
The organelle of a eukaryotic cell that contains the genetic information in the forms of chromosomes, made of chromatin.
614
Define Nuclear Envelope
In eukaryotic cells, the double membrane that surrounds the nucleus, perforated with pores that regulate traffic with the cytoplasm. The outside membrane is continuous with the ER.
615
Define Chromosomes
A structure containing DNA and its associated proteins. In eukaryotes, chromosomes are linear and located in the nucleus. In prokaryotes, the chromosomes are circular and located in the nucleoid.
616
Define Chromatin
The complex of DNA and proteins that makes up the chromosomes.
617
Define Ribosomes
A complex of rRNA and protein molecules that functions as a site of protein synthesis in the cytoplasm; consists of a small and large subunit.
618
What are the two types of ribosomes and where are they located?
Free ribosomes and bound ribosomes.
Free ribosomes are suspended in the cytosol, while bound ribosomes are attached to rough ER.
619
What is the function of free ribosomes?
Most the proteins made on free ribosomes function within the cytosol.
620
What is the function of bound ribosomes?
They generally make proteins that are destined for insertion into membranes.
621
What is the endo-membrane system responsible for?
Regulating the traffic of proteins and performing metabolic functions.
622
Define Vesicle
A membranous sac in the cytoplasm of a eukaryotic cell.
623
Define Endoplasmic Reticulum
An extensive membranous network, continuous with the outer membrane of the nucleus and composed of ribosome free and studded regions.
624
Define Smooth ER
The portion of the ER that is free of ribosomes.
625
Define Rough ER
The portion of the ER that contains the ribosomes.
626
What are the general functions of the smooth ER.
Diverse metabolic processes.
627
How does the smooth ER detoxify drugs and poisons?
They usually involve the addition of a hydroxyl group, making them more soluble and easier to flush out of the system.
628
Define Transport Vesicles
A small membranous sac in a eukaryotic cell’s cytoplasm carrying molecules produced by the cell.
629
Define Golgi Apparatus
An organelle in eukaryotic cells consisting of stacks of flat membranous sacs that modify, store, and route the products of the ER and synthesize some products, notably non-cellulose carbs. G-MSR
630
What are the two sides of the Golgi called?
Cis/Trans
631
Where is the cis side and the trans side of the Golgi located?
Cis is facing the ER; trans is the opposite side of cis. CG
632
What are the functions of the cis/trans side of the Golgi respectively?
Cis —-> Recieving; Trans—-> Sending. CRTS
633
Define Lysosome
A membrane-enclosed sac of hydrolytic enzymes found in the cytoplasm of animal cells and some plant cells.
634
In which environments do lysosomes do best?
Acidic
635
What is the main function of the lysosome?
Carrying out intracellular digestion in a variety of circumstances.
636
Define Authopagy
When lysosomes use their hydrolytic enzymes to recycle a cell’s own organic material.
637
Define Vacuoles
A membrane-bound vesicles whose specialized function varies in the cell.
638
Vacuoles are derived from the _____ and the ______.
ER-Golgi
639
Define Central Vacuole
In a mature plant cell, a large membranous sac with diverse roles in growth, storage, and sequestration of toxic substances. C-GSS
640
How do plant cells grow?
With the absorption of water, the central vacuoles of cells grow, causing the cell to become larger.
641
Define Mitochondria
An organelle in eukaryotes that serves as the site of cellular respiration; uses oxygen to break down organic molecules and synthesize ATP.
642
_____ and _____ change energy from one form to a another.
Mitochondria-Chloroplast
643
Define Chloroplasts
An organelle found in plants that absorbs sunlight and uses it to drive the synthesis of organic compounds from carbon dioxide and water.
644
Define the Endosymbiont Theory
The theory that the mitochondria and chloroplasts originated as prokaryotic cells engulfed by a host cell. The engulfed cell and its host cell the evolved into a single organism.
645
How many membranes does the mitochondria have?
2
646
The outer membrane of the mitochondria is _____, but the inner membrane is _____.
Smooth-Convoluted
647
Define Cristae
An inner folding of the inner membrane of the mitochondria. The inner membrane houses electron transport chains and molecules of the enzyme catalyzing the synthesis of ATP.
648
Define Mitochondrial Matrix
The part of the mitochondria of the inner membrane that contains the enzymes and the substances on which an enzyme acts on for the citric acid cycle, as well as ribosomes and RNA.
649
Define Thylakoids
A flattened, membranous sac inside a chloroplast.
650
Define Granum
A stack of membrane bound thylakoids in the chloroplast. They function in the light reactions of photosynthesis.
651
Define Stroma
The dense fluid within the chloroplast surrounding the thylakoids membrane.
652
Define Peroxisome
An organelle containing enzymes that transfer hydrogen atoms from various substrates to oxygen, producing and then degrading H2O2.
653
Peroxisomes are bound by a _____ membrane.
Single
654
What are some functions of the peroxisomes?
They use oxygen to break down fatty acids; in the liver, they break down alcohol.
655
The _____ is a network of fibbers that organize structures and activities in the cell.
Cytoskeleton
656
Define Cytoskeleton
A network of microtubules, microfilaments, and intermediate filaments that extend throughout the cytoplasm and serve a variety of mechanical, transport, and signaling functions.
657
Which of the three components of the cytoskeleton are the thinnest/thickest?
Thickest: Microtubules
Thinnest: Microfilaments
658
Define Microtubules
A hollow rod composed of tubulin proteins that makes up part of the cytoskeleton in all eukaryotic cells that are found in the cilia and the flagella.
659
What are the main functions of Microtubules?
They support the cell structure and also act as a track along which organelles equipped with motor proteins can move along.
660
In animal cells, microtubules grow out of the _____.
Centrosome.
661
Define Centrosome
A structure present in the cytoplasm of animal cells that functions as the microtubule organizing center and is important during cell division. A Centrosome has 2 centrioles.
662
Define Flagella
A long cellular appendage specialized for locomotion.
663
Define Cilia
A short appendage containing microtubules in eukaryotic cells.
664
Do motile cilia and flagella have a similar structure?
Yes
665
Define Microfilaments
A cable composed of actin proteins in the cytoplasm of almost every eukaryotic cell, making up part of the cytoskeleton and acting alone or with myosin to cause cell contraction.
