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BSCI 330: Cell Biology > Post Exam 3 Material > Flashcards

Post Exam 3 Material Flashcards

1
Q

Epigenetic Inheritance

A
  • Any heritable difference that does not rely on changes in a DNA sequence
  • Basis for cell differentiation
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2
Q

Mechanisms that contribute to epigenetic changes

A
  • Positive feedback loop for regulatory proteins
  • Covalent modification to histones and chromatin structure
  • Methylation of DNA on cytosine residues
  • Prions
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3
Q

Positive feedback loop of a regulatory protein

A

Once a protein is made, it maintains its own expression which provides a stable phenotype

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4
Q

Covalent modification of histones

A

Recruits enzymes that maintain chromatin structure in daughter cells

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5
Q

Methylation of cytosine

A
  • Suppresses gene transcription
  • Methyltransferase maintains methylation patterns during DNA replication
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6
Q

Protein Aggregation (Basis of Prion Disease)

A
  • Proteins can adopt an alternate form that induces self-aggregation and catalyzes a conformational change in normally folded protein molecules to make them misfolded (prions)
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7
Q

Eukaryotic Cell Compartments

A

Subdivided into functionally distinct membrane-enclosed compartments

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8
Q

Gated Transport (Nucleus)

A
  • Bidirectional between cytosol and nucleus
  • Occurs through nuclear pore complexes
  • Selective gates that actively transport macromolecules
  • Allows free diffusion of smaller molecules
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9
Q

Transmembrane Transport (Mitochondria)

A
  • Unidirectional between cytosol and organelles that are topologically different
  • Occurs through membrane-bound protein translocators
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10
Q

Vesicular Transport

A
  • Bidirectional from ER to Golgi and to designated locations
  • Among topologically similar organelles
  • Occurs through vesicles
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11
Q

Topological Similarities

A

Compartments with similar transport mechanisms

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12
Q

Sorting signals and receptors

A
  • The movement of proteins between organelles is mediated by sorting signals and receptors
  • These signals are recognized by protein-sorting receptors
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13
Q

Nucleoporins

A

Contain unstructured regions that restrict the passage of large macromolecules between the cytosol and nucleus

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14
Q

Initiation of nuclear import

A

Nuclear localization signals (NLS) within cargo must be recognized by nuclear import receptors

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15
Q

Cargo

A

Material that is carried by vesicles

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16
Q

Nuclear Localizations Signal Sequences

A
  • Only present in nuclear proteins
  • 5 basic amino acids in a row
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17
Q

Nuclear Transport

A
  • Import of nuclear proteins through the pore complex
  • Increases order in the cell (Non-Spontaneous)
  • Consumes energy provided by GTPase: specifically Ran
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18
Q

Ran

A
  • GTP-bound protein
  • Found in the cytosol and nucleus
  • Required for nuclear import and export
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19
Q

RAN-GEF

A
  • Nuclear protein
  • Catalyzes binding of GTP to RAN
  • There is more RAN-GTP inside the nucleus than the cytosol
  • GTP bound
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20
Q

RAN-GAP

A
  • Cytosolic protein
  • Activates hydrolysis of GTP attached to RAN
  • GDP Bound
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21
Q

RAN and nuclear import/export

A
  • RAN GAP dephosphorylates RAN GTP into RAN GDP in the cytosol
  • This causes RAN GDP to pick up and bind to cargo in the cytosol
  • This is imported into the nucleus where RAN GEF replaces GDP with GTP and releases the cargo in the nucleus
  • RAN GTP is then transported out of the nucleus through nuclear pore complexes and the process repeats
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22
Q

Nuclear Import

A

RAN GTP binding to import receptor causing the cargo to be released

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23
Q

Nuclear Export

A

RAN GTP binding to export receptor causing the cargo to bind

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24
Q

NFAT and Nuclear Transport

A
  • Rise in calcium levels activates calcineurin
  • Calcineurin dephosphorylates NFAT which causes a conformational change, exposing a nuclear import sequence on the protein’s surface
  • NFAT enters the nucleus and triggers gene expression of T-cells in their role in immune response
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25
Q

Location of proteins in mitochondria

A
  • Outer membrane
  • Inner membrane
  • Intermembrane space
  • Matrix space
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26
Q

Mitochondrial transport

A
  • Mitochondrial proteins are first fully synthesized as precursor proteins in the cytosol and are then translocated into the mitochondria
  • Need an import signal sequence
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27
Q

Import signal of mitochondrial transport

A
  • Amphipathic alpha helix at N-terminus
  • Charged residues on one side and uncharged on the other side
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28
Q

Protein translocators of mitochondrial transport

A
  • TOM complex (1)
  • TIM complex (2)
  • These complexes need to be unfolded
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29
Q

TOM Complex

A
  • Functions across the OUTER membrane
  • All nucleus-encoded proteins must interact with TOM first
  • Helps insert transmembrane proteins into the outer membrane
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30
Q

TIM Complexes

A
  • Function across the inner membrane
  • Spans on both the inner and outer membranes
  • Transport soluble proteins into the matrix
  • Import ATPase complex binds and pulls proteins through the TIM channel
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31
Q

Chaperones

A
  • Place proteins in an isolated environment to assist in maintaining proper folding
  • Most common is Hsp70
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32
Q

Co-translational translocation (ER)

A
  • Used by proteins entering the ER
  • Need an ER signal sequence
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33
Q

Types of proteins that use co-translational translocation

A
  • Secretory proteins are destined to the lumen of any non-nuclear organelle to be secreted out of the cell
  • Transmembrane proteins are destined to the membrane of an organelle membrane
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34
Q

ER signal sequence

A
  • N-terminal
  • Hydrophobic
  • Contain 8 or more AA
  • Recognized by SRP receptors in the ER membrane
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35
Q

SRP

A
  • Signal recognition particle
  • Contain both RNA and protein components
  • RNA: blocks elongation factor binding site
  • Protein: binds signal sequence
  • NOT a ribozyme because it does not catalyze a reaction
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36
Q

Positively charged amino acids

A

ALWAYS face the CYTOSOL

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37
Q

Single-pass integral membrane protein

A
  • Signal/start sequence is cleaved
  • Hydrophonic stop transfer sequence anchors the protein in the membrane
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38
Q

Multi-pass integral membrane proteins

A
  • Multiple start and stop-transfer sequences
    The first start sequence is the signal sequence
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39
Q

ODD number of transmembrane proteins

A

N and C-terminus on OPPOSITE sides

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40
Q

EVEN number of transmembrane proteins

A

N and C-terminus on SAME side

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41
Q

Amount of alpha helices it takes to get past the transmembrane region once

A

8 alpha helices

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42
Q

Forward transport

A

ER to Golgi to destination

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43
Q

Retrograde transport

A

Used to pick up more proteins or if there was a mistake in designating proteins to the wrong destination

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44
Q

Protein coats

A
  • Vesicular transport depends on protein coats formed at specific locations along donor compartments
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45
Q

Initial step in vesicle formation

A
  • Transport vesicles have a cage of proteins covering their cytosolic surface
  • The protein coat of the vesicles is discarded to allow 2 cytosolic membrane surfaces to interact directly and fuse
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46
Q

Types of coat proteins

A
  • COPII
  • COPI
  • Clathirin
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47
Q

COPII

A

Coats ER to Golgi vesicles

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48
Q

COPI

A

Coats vesicles moving from:
- Golgi to ER
- Golgi to the plasma membrane
- Within the Golgi

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49
Q

Clathrin

A
  • To/from endosomal compartments
  • Within endosomal compartments
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50
Q

Phosphatidyl-inositol (PI)

A
  • Mark organelles and membrane domains
  • Inositols can get phosphorylated by lipid kinases
  • Recruit various proteins that possess lipid-binding domains
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51
Q

Lipid-binding domains

A

Recognize a specific type of phosphatidyl-inositol

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52
Q

Adapter proteins

A
  • Bind to membrane proteins and recruit coat proteins
  • Bind to cargo receptors
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53
Q

Types of GTPases control coat assembly

A
  • Sar-1 regulates COPII assembly
  • Arf proteins regulate COPI and clathrin assembly
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54
Q

What are 3 types of GTP binding proteins and what do they control?

A
  • Arf proteins: Control coat assembly and vesicular traffic
  • RAN: Regulates protein transport across the nuclear membrane
  • Rabs: Targets the vesicle to the correct destination
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55
Q

Sar1-GDP

A
  • Cytosol
  • Inactive
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56
Q

Sar1-GTP

A
  • Integral membrane protein
  • ER membrane-bound
  • Active
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57
Q

Sar1-GEF

A

Sar1-GEF is activated when GDP is released from Sar1 and GTP binds to Sar1

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58
Q

Vesicle docking and tethering

A
  • Transport vesicles must be highly selective in recognizing the correct target membrane with which to fuse
  • Surface markers identify vesicles according to their origin and type of cargo
  • Target membranes display complementary receptors that recognize the appropriate markers
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59
Q

SNARE proteins

A
  • NOT GTP-Binding (ATP-regulated)
  • Provide specificity
  • Catalyze vesicular fusion with the target membrane
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60
Q

v-SNAREs

A

Vesicle

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61
Q

t-SNAREs

A

Target membrane

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62
Q

Rab proteins

A
  • Small GTPases
  • Initial contact with the target membrane
  • Work with other proteins to regulate the initial docking and tethering of the vesicle to the target membrane
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63
Q

Entry of vesicles leaving the ER

A
  • Membrane proteins have exit signals in their cytosolic tails that are recognized by COPI coat proteins
  • Soluble proteins bind to cargo receptors that have exit signals in their cytosolic tails (ex. KDEL receptors)
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64
Q

Vesicular Tubular Clusters

A
  • These clusters are transport vesicles leaving the ER that fuse together to form intermediate components
  • Clusters travel towards the cis (close to ER) Golgi via motor proteins on microtubule tracks
  • Generate coated vesicles going back to ER (COPI coat): Retrograde
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65
Q

Models for how cargo travels through Golgi

A
  • Vesicular Transport (Static)
  • Cisternal Maturation (Dynamic)
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66
Q

Vesicular Transport Model

A
  • Static cisternae
  • Vesicles travel between them
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67
Q

Cisternar Maturation Model

A
  • Dynamic cisternae
  • Cisternae move upward and change their properties slightly as they migrate
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68
Q

Exocytosis

A
  • Vesicles carry proteins leaving the Golgi to fuse with the plasma membrane
  • Membrane proteins and lipids become part of the plasma membrane
  • Soluble proteins are secreted into the extracellular space
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69
Q

Regulation of Exocytosis

A

Rabs and SNAREs

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70
Q

Types of Transport from Trans Golgi (faces cytoplasm) to the Cell Exterior

A
  • Constitutive secretory pathway
  • Regulated secretory pathway
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71
Q

Constitutive secretory pathway

A

No additional signal is needed to fuse vesicles with plasma membrane after Rabs and SNAREs

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72
Q

Regulated secretory pathway

A
  • Concentrates cargo in small volumes
  • Fusion does not happen immediately when in contact with a plasma membrane until a signal is received (Usually Calcium)
73
Q

Secretory vesicles

A
  • Specialized for secreting products rapidly and on demand
  • Only release their contents in response to extracellular signals
74
Q

Clathrin-coated vesicles

A
  • Composed of 3 copies each of heavy chain and light chain
  • Arranged in a 3-arm pinwheel
75
Q

Features of Clathrin coats

A
  • Assemble on the plasma membrane
  • Recruited by adaptor proteins
  • Capture and package cargo molecules within the donor compartment into a budding vesicle
  • Coat is rapidly lost after forming
76
Q

Dynamin

A
  • Lipid-binding GTPase
  • Protein that pinches off the clathrin-coated vesicles
  • Oligomerizes (wraps) around the stem of the budding vesicle
  • Brings inner leaflet membranes of vesicles together
  • Fusion of these membranes releases the vesicles from the donor compartment
77
Q

Lysosomal Enzyme Cargo

A
  • Soluble
  • Carries M6P groups that are added to N-linked oligosaccharides in cis-Golgi
  • Recognized by M6P receptor in TGN and packaged into clathrin-coated vesicles for delivery to lysosomes
78
Q

Intermediate organelles in vesicular transport pathways

A
  • Vary in shape and size
  • Receive cargo from Golgi and Plasma membrane
79
Q

Classes of Intermediate Organelles

A
  • Early
  • Late
  • Recycling
80
Q

Endosome maturation

A
  • Early endosomes mature into late endosomes which mature into lysosomes
  • Becomes increasingly acidic during this process
81
Q

Endocytosis

A
  • Budding and internalization of vesicles
  • Membrane proteins and lipids are removed from the plasma membrane where some are recycled back to the surface and others will be degraded
  • Soluble proteins from the extracellular space will be carried into the lumen
82
Q

Types of Endocytosis

A
  • Based on the size of vesicles
  • Phagocytosis
  • Pinocytosis
83
Q

Phagocytosis

A
  • Ingestion of large particles such as microorganisms or dead cells
  • Vesicles are called phagosomes
84
Q

Pinocytosis

A
  • Ingestion of fluid and solutes
  • Vesicles are called pinocytic vesicles
  • Includes receptor-mediated endocytosis
85
Q

Receptor-mediated endocytosis

A
  • Triggered by extracellular signaling
  • Ex. Cholesterol gets into cells via this pathway
86
Q

Transcytosis

A

Molecules internalized at one end of a polarized cell are transported to a different end

87
Q

Passive Transport

A
  • Moving a solute DOWN its concentration gradient
  • High to low concentration
  • Does NOT require energy
88
Q

Examples of Passive Transport

A
  • Ion channels
  • Facilitated diffusion
89
Q

Active transport

A
  • Moving a solute UP its concentration
  • Low to high concentration (AGAINST)
  • Requires energy
90
Q

Where does the energy for active transport come from?

A
  • ATP
  • Movement of something else DOWN a gradient
  • High energy electrons
91
Q

Characteristics of Biological Membranes

A
  • Semipermeable
  • Small, nonpolar molecules diffuse freely
  • Large, polar, charged molecules require channels and transporters
92
Q

Channels

A
  • Allows diffusion DOWN a concentration gradient
  • ALWAYS passive transport
  • Only need 1 conformational change
93
Q

Transporters

A
  • Use conformational changes to move substrates across the membrane
  • May transport down or up a concentration gradient
94
Q

Diffusion

A
  • Random motion of molecules: They will sometimes move toward each other or away from each other
  • High to low concentration
  • Down a concentration gradient
95
Q

Change in free energy

A

Any molecule or ion moving down or up a concentration gradient requires a change in free energy

96
Q

Diffusion of charged molecules

A
  • Involves electrochemical gradient
  • Differences are additive
97
Q

Positive Delta G

A

Active transport (non-spontaneous)

98
Q

Negative Delta G

A

Passive transport (spontaneous)

99
Q

Ranking of Permeability

A
  • Hydrophobic (Best)
  • Small, uncharged, polar
  • Large, uncharged, polar
  • Ions (Worst)
100
Q

Simple diffusion

A
  • Free Diffusion is limited to small, uncharged, and non-polar molecules
  • Bidirectional
  • Unsaturable: As you increase the concentration of the molecules, you increase the rate of diffusion
101
Q

Transporter-mediated diffusion

A
  • Always down the concentration gradient (High to low)
  • Can go in or out of the cell
  • Saturable (similar to enzyme kinetics): Reach a maximum rate
102
Q

Ion channels

A
  • Allows a net flux of specific ions DOWN their electrochemical gradient
  • Undergo one conformational change
103
Q

Open ion channels

A
  • Stable state
  • Induced by a conformational change
104
Q

Closed ion channels

A

Close when a signal arrives and closes it

105
Q

Channel structure

A
  • Central pore lined with hydrophilic R groups
  • Subunits around the pre are often formed from alpha helices
  • Highly selective
106
Q

Conformational changes that OPEN an ion channel

A
  • Ligand-gated channels
  • Voltage-gated channels
  • Mechanosensitive channels
  • Temperature-sensitive channels
107
Q

Facilitated Diffusion-Passive transport

A
  • Neutral, polar molecules that are larger than water or urea
  • NOT couples with an energy source
  • The direction of molecules follows the electrochemical gradient
  • Solute binds tightly to a highly specific site on protein and causes a conformational change
  • Transitions between states are random and reversible
  • Slower than ion-channel transport
108
Q

Facilitated Diffusion Proteins

A
  • Do not alter Delta G
  • Always DOWN electrochemical gradient
  • Act like enzymes by speeding up movement
109
Q

Type of facilitated diffusion

A

Glucose transport

110
Q

Door Analogy for channel and transport-mediated diffusion

A
  • Ion Channel Mediated: Handicap button
  • Transport Mediated: Revolving door
111
Q

Types of Active Transport

A
  • ATPase pumps
  • Non-ATP pumps that use physical forces
  • Couples transporters that use the energy of the gradient itself
112
Q

Coupled Transport

A
  • Can move molecules up or down a concentration gradient
  • Occurs via symports and antiports
113
Q

Symports

A

Move both molecules in the same direction

114
Q

Antiports

A

Move molecules in opposite physical directions

115
Q

Types of ATP-driven pump proteins

A
  • P-type
  • F-type and V-type
  • ABC transporter
116
Q

P-type pumps

A
  • Move ions from one side of the membrane to another
  • Multipass transmembrane proteins
  • Ex. Calcium ATPase, Na+/K+ Pump
117
Q

Na+/K+ Pump

A
  • This pump has specific binding sites for sodium and potassium
  • Antiporter
  • Active transport (UP)
  • Have to pump both of them for both to be pumped
118
Q

F-type pumps

A
  • Reversible
  • Found in bacteria, mitochondria, and thylakoid membranes
  • Generate ATP through H+ gradient
  • Called ATP synthases as they drive the synthesis of ATP from ADP + Pi
119
Q

V-type pumps

A
  • Made of multiple subunits
  • Use ATP but NOT via a phosphorylated intermediate
  • Found in membranes of lysosomes, synaptic vesicles, and plant vacuoles
  • Regulate pH by pumping H+ into these compartments
120
Q

ABC transporters

A
  • Homodimers: 2 subunits
  • Multiple domains
  • Most of these transporters pump small, uncharged molecules
  • Some pump ions
  • Ex. MDR proteins
121
Q

ABC transporters in Bacterial cells

A

Pump molecules INTO the cell

122
Q

ABC transporters in Eukaryotic cells

A

Pump molecules OUT of the cell

123
Q

Cytoskeleton

A
  • System of protein filaments that provides structure and mechanical support for the cell
  • Made by the polymerization of the monomeric protein subunits
124
Q

Types of fibers that make up the cytoskeleton

A
  • Microtubules
  • Microfilaments
  • Intermediate filaments
125
Q

Monomers of microtubules

126
Q

Monomers of microfilaments

127
Q

Monomers of intermediate filaments

A
  • Helical proteins
  • Ex. keratin in epithelial cells, lamins in nucleated cells, neurofilament proteins in axons
128
Q

Feature of cytoskeleton interactions

A
  • Noncovalent attractions of small subunits
  • Disassembly and reassembly allow for changes in cell shape and internal movement of organelles/vesicles
129
Q

Polymerization of Cytoskeleton proteins

A
  • Requires NTP
  • Monomers containing NTP have a higher affinity for their binding partners
  • NTP-bound to (+) end of growing filament
130
Q

NTP vs. NDP

A
  • NTP allows for polymerization
  • NDP results in depolymerization
131
Q

Actin

A
  • Flexible filaments
  • Soluble and globular protein
  • Most abundant protein
  • Dispersed throughout a cell
  • Highly concentrated beneath the plasma membrane
  • Forms the basis of cell shape and structure
  • Aid in the contraction of muscle cells
132
Q

Actin monomers

A

Globular actin (G-actin)

133
Q

Actin polymers

A

Filamentous actin (F-actin)

134
Q

ATP-G vs. ADP-G actin

A

ATP-G actin monomers bind more tightly to each other than ADP-G actin monomers

135
Q

Actin +/- ends

A
  • Actin monomers (G-actin) bound to ATP are added to the (+) end of the growing filament
  • Actin-ADP monomers are lost from depolymerizing the (-) end
136
Q

Treadmilling

A

The addition of an ATP-G-actin monomer to the (+) end if equivalent to the removal of an ADP-G actin monomer at the (-) end

137
Q

Proteins that regulate actin

A
  • Arp 2 and 3: monomers nucleating
  • Thymosins: inhibit polymerization
  • Tropomodulin: capping (block) plus or minus ends
  • Fimbrin: stiffens cytoskeleton
  • Cofilin: promotes depolymerization
  • Profilin: promotes extension
  • Gelsolin: breaks down the gel of long filaments which decreases the viscosity
138
Q

Rho family of GTPases

A
  • These GTPases regulate the proteins that regulate actin
  • Act as molecular switches to control actin polymerization
139
Q

Rho-GTP

A

Regulate actin bundling

140
Q

Ran-GTP

A

Regulate actin polymerization

141
Q

Cdc42-GTP

A

Regulate actin polymerization and bundling

142
Q

Microtubules

A
  • Rigid tubules that are spread throughout the cytoplasm of ALL eukaryotic cells
  • Form mitotic spindles and the core of cilia and flagella
143
Q

Structure of tubulin

A
  • Tubulin heterodimers (alpha and beta tubulin) polymerize into protofilaments which assemble into microtubules
144
Q

Alpha tubulin

A

Can only bind to GTP

145
Q

Beta tubulin

A

Can bind to GTP or GDP

146
Q

Tubulin +/- ends

A
  • Tubulin dimers bound to GTP are added to the (+) end of microtubules
  • GTP is eventually hydrolyzed into GDP
147
Q

GTP cap (tublin-GTP dimer)

A
  • The rate of polymerization at the (+) end is more rapid than GTP hydrolysis
  • The cap is put into place to stabilize the growth
148
Q

Catastrophe

A
  • GTP cap is lost
  • The (+) end undergoes rapid depolymerization
  • The rate of GTP hydrolysis exceeds the rate of polymerization
149
Q

Compare tubulin and actin under cellular conditions

A
  • Tubulin: growth and loss occur at the (+) end, normally has a GTP cap, and if the cap is lost then it will lead to depolymerization
  • Actin: growth and loss occur at both ends, Addition at the (+) end, Loss at the (-) end
150
Q

Proteins that regulate the addition and removal of tubulin dimers

A
  • Stathmin: binds subunits and prevents assembly
  • Kinesin: enhances disassembly
  • Katanin: breaks microtubules
  • MAP: binds along tubules and stabilizes them
  • XMAP: stabilized (+) end
  • TIPS: associated with (+) end and links them to other structures
151
Q

Phases of microtubule regulation

A
  • Nucleation
  • Elongation
152
Q

Nucleation

A
  • A small portion of tubule formed at the beginning
  • Associated with MTOC’s
153
Q

Elongation

A

Addition of tubulins and GTP-cap

154
Q

Example of MTOC

A
  • Centrosomes
  • Found in animal cells
  • DividedGamme prior to cell division
155
Q

Gamma tubulin

A
  • Found in centriole microtubules
  • Bound to the (-) end
156
Q

Molecular motors

A
  • Proteins act as molecular motors by changing shape to generate movement
  • The movement must be directional in order to be useful
157
Q

Favorable movement

A
  • ATP hydrolysis (ATP to ADP + Pi)
158
Q

Myosin

A
  • A motor protein that binds to actin microfilaments
  • Subdivided into Myosin II
159
Q

Features of myosin II

A
  • Heterodimer
  • S1 head involved with movement via ATPase activity
  • Neck region
  • Coil-to-coil region
160
Q

Myosin II Actin Filaments

A
  • Myosin II can associate with actin filaments which are highly stable in muscle cells
  • From the basic structural unit of contractility (sarcomere)
  • Myosin II moves these filaments through the Powerstroke
161
Q

Microtubule motor proteins

A
  • Kinesins
  • Dyneins
162
Q

Kinesins

A
  • Responsible for moving vesicles and organelles along nerve axons
  • Composed of 2 light chains and 2 heavy chains
  • Globular heads contain ATP binding site
163
Q

ATP-binding site of kinesin

A
  • Binds to microtubule which initiates ATPase activity and the movement of kinesin and cargo
  • Movement only occurs in the direction of (-) to (+) end
164
Q

Cargo of kinesin

A
  • Includes vesicles, protein complexes, and organelles
  • Bound to kinesin via adapter proteins
165
Q

Dyneins

A
  • Contain 2 ATP-binding heads
  • Light chain is bound to cargo through dynactin
  • Dynein molecules move along the microtubule from the (+) to (-) end
166
Q

Intermediate filaments

A
  • Composed of long helical proteins
  • Provide mechanical strength
  • Not present in every cell
167
Q

Which cytoskeleton processes use ATP hydrolysis?

A
  • De/polymerization of actin filament
  • Movement of myosin along actin
  • Movement of kinesin and dynein along tubulin
168
Q

Which cytoskeleton processes use GTPase activity?

A

De/polymerization of tubulin filaments

169
Q

Cellular metabolism

A

Occurs in small enzyme-catalyzed steps that allow energy to be stored and extracted in useful ways

170
Q

What parts of cellular metabolism require molecular oxygen?

A

TCA and ETC

171
Q

What part of cellular metabolism does NOT require molecular oxygen?

A

Glycolysis

172
Q

Features of cellular metabolism

A
  • Energy for cellular processes comes from catabolic reactions (breaking things down)
  • In order to harvest energy, nutrients must be oxidized (lose electrons) in small steps
173
Q

Benefits of small enzyme-catalyzed steps

A
  • Avoids the release of heat
  • Reduces the activation energy
  • Enzymes couple unfavorable reactions with energetically favorable reactions
  • Small delta G’s
174
Q

Glycolysis

A
  • One molecule of glucose is converted to two molecules of pyruvate
  • Net production of 2 ATP and 2 NADH molecules
  • Occurs in the cytosol
175
Q

Phases of glycolysis

A
  • Investment
  • Cleavage
  • Energy generation
176
Q

Investment phase

A

Glucose is phosphorylated twice

177
Q

Cleavage phase

A

The phosphorylated molecule splits into two molecules

178
Q

Energy generation

A

The two molecules are oxidized to produce NADH

BSCI 330: Cell Biology (4 decks)

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