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Unit 2 Flashcards

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1
Q

Describe the general function of biological membranes

A

provide structural basis for metabolic order (without membrane no homeostasis/metabolism)

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2
Q

Describe the fluid mosaic model of plasma membrane structure and describe the experiment for this model

A

Mouse and human cells were fused to show that plasma membrane proteins and phospholipids must be able to move around bilayer, since its fluid

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3
Q

What is membrane fluidity

A

fluid state of the membrane which depends on lipid components (alter quantity of unsaturated fatty acids in response to temperature changes)

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4
Q

What are the 3 main functions of the plasma membrane

A

1-separate the cell from the exterior
2-create a controlled intracellular envrionment
3-Selective permeability: allow some molecules to enter and dispose of waste

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5
Q

Describe the relationship between membrane fluidity and membrane permeability

A

Proportional relationship= if fluidity decreases so does permeability (more rigid so harder for molecules to pass through and vice-versa)

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6
Q

Describe relationship between membrane fluidity and temperature

A

if temp increase=membrane becomes too fluid/flexible= cant hold its shape

if temp decreases= membrane becomes too rigid and can even break

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7
Q

Describe relationship between membrane fluidity and saturation of fatty acids

A

saturated fatty acids reduce fluidity of membrane since they’re solid at room temp

unsaturated fatty acids increase fluidity since liquid at room temp

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8
Q

Describe relationship between membrane fluidity and length of fatty acids

A

the longer the chain=more rigid since stronger LDF forces

shorter fatty acid=more fluid since less LDF

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9
Q

Describe relationship between membrane fluidity and amount of cholesterol

A

increased cholesterol in the membrane means it will adjust to temp changes more easily (maintain fluidity)

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10
Q

What is the role of cholesterol in the membrane

A

acts as fluidity buffer
-if membrane becomes too fluid=it binds to hydrophilic head to stabilize it (restrain phospholipid mouvement)

-if membrane too rigid=inserts itself between fatty acid tails to reduce LDF

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11
Q

What is homeoviscous adaptation

A

the ability to change the fatty acid content of membrane lipids to maintain its fluidity

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12
Q

What is selective permeabilty and the 2 types of membrane transport

A

ability of membrane to allow some molecules to pass and block others (affected by size/polarity)

Active and passive transport

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13
Q

What are the 2 kinds of membrane proteins

A

integral (inside) and peripheral (outside)

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14
Q

Describe integral protein

A

assembled by rough ER ribosomes and bounded to the bilayer (in the core)
Amphipathic molecules but mostly non polar (made of nonpolar amino acids)

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15
Q

True of false
All integral proteins extend from one end to the other (of plasma membrane)

A

False

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16
Q

What are called proteins that extend along the phospholipid bilayer

A

transmembrane protein

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17
Q

Why are transmembrane protein amphipatic

A

To be able to bind with the hydrophobic and hydrophillic part of membrane

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18
Q

Describe peripheral membrane protein

A

membrane protein on the inner or outer surface (not embedded)
If on the outside surface=made by rough ER
if on inner surface=made by free ribosomes
Can perform enzymatic/receptor functions

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19
Q

Give an example of intergral protein

A

aquaporins or glycoproteins

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20
Q

Explain the assymetrical distribution of the cytoplasmic and extracellular face of PM

A

asymmetry is produced by the high specific way each protein is inserted
asymmetry gives each side specific characteristics

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21
Q

Why is selctive permeability important

A

it allows the cell to control and maintain its internal components (what comes in/out of the cell)

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22
Q

How do membrane lipids and membrane proteins contribute to selective permeability

A

membrane protein aid the transport of certain molecules in/out of cell and membrane lipid maintain fluidity constant to allow for the transport of molecules through the bilayer.

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23
Q

State the 6 major functions of membrane proteins

A

intercellular joining
cell-to-cell recognition
transport
enzymatic fxn
attachement to the ECM
signal transduction

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24
Q

Describe cell-cell recognition

A

provides identity tages for cell
important for immune systems=allows it to regognize and reject foreign bodies
enables cellsto sort themselves into tissue/organs

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25
Q

What are autoimmune diseases

A

immune system fails to distinguish own cells from foreign ones so it attcks healthy cells.

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26
Q

Describe intercellular joining

A

membrane protein of neighbouring cells hook together via different junctions

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27
Q

What are the different kinds of junctions in plant cells

A

plasmodesmata

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28
Q

What are the different kinds of junctions in animal cells

A

desmosomes (for anchoring)
gap junction (for communications)
tight junctions (for leaks)

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29
Q

describe briefly the plasmodesmata

A

channels for rapid communication between plant cells that can dilate
connects PM and cell wall
allows for small molecules/ions/water excahneg and chemical signalling

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30
Q

describe briefly the desmodomes

A

attaches adjacent animal cells without stop passage of sybstances in between
very strong
made of button discs (on cytosplasmic side) and intermediate filaments

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31
Q

What is the purpose of intermediate filaments

A

redistribute mechanical stress on tissue

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32
Q

Why cant plant cells have a desmodomes

A

they have a strong cell wall

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33
Q

describe briefly tight junctions

A

proteins are physical attched= form sheet of tissue
tightly attaches animal cells to prevent any substance leaks

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34
Q

Where would tight junctions be found

A

stomach (prevent acid secretions)
brain capillaries

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35
Q

describe briefly gap junctions

A

brigde space with a channel between animal cells for rapid chemical and electrical communication
connects the cytoplasm of adjacent cells

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36
Q

Where would gap junctions be found

A

heart cells and pancreas

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37
Q

Describe the membrane protein that create attachements to ECM

A

membrane protein that do not move and keep the membran in place
not covenlently bonded to ECM fibers/cytoskeleton

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38
Q

How does the ECM work

A

made of glycoprotein/lipids (like collagen)
has fibronectin that connect to integrin which connect to cytoskeleton

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39
Q

What are fibronectins

A

glycoprotein that organize the matrix and aid cell in attaching to matrix by binding with integrins

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40
Q

what are integrins

A

integral transmembrane proteins that function in cell signalling (ECM receptor), organize cytoskeleton (maintain shape/mouvement) and anchor ECM to microfilaments

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41
Q

Describe the process of diffusion

A

mouvement of solute across a membrane, due to its concentration gradient (high to low) until eq is reached
doesn’t need energy input

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42
Q

True or false
Diffusion is not spontaneous

A

false it is

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43
Q

What is net diffusion

A

net mouvement of particles

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44
Q

What is dynamic equilibrium in diffusion

A

concentration gradient no longer exists= no net mouvement BUT particles are still moving across membrane

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45
Q

What factors affect the rate of diffusion of a substance

A

temperature, steepness of concentration gradient, idk

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46
Q

Does diffusion reach eq in cells

A

no since the envrionement is always changing

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47
Q

What is the difference between facilitated and simple diffusion in cells

A

simple: molecules diffuses freely (non polar compound)
facilitated diffusion: transport proteins speed up mouvement of polar/ large molecules across the membrane

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48
Q

What are channel proteins

A

gated membrane protein that open/close to regulate passage of solute
provide hydrophilic corridor for polar molecules to pass
ex: aquporin of ion channels

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49
Q

What are carrier proteins

A

proteins that undergo shape change once they bind with solute cause translocation of binding site across membrane

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50
Q

Are carrier proteins faster or slower than channel proteins and why

A

slower since they change shape

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51
Q

What are the 3 types of carrier proteins

A

uniporter
symporter
antiporter

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52
Q

Define osmosis

A

movement of water across a semi permeable membrane
osmosis is driven by impermeable solute only BUT water is the one that moves across and dissipate the gradient (low to high)

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53
Q

Is osmosis spontaneous

A

yes

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54
Q

Define osmotic pressure

A

hydrostatic pressure needed to stop net flow of water across membrane due to osmosis

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55
Q

Define tonicity

A

the ability of a solution to cause a net gain/loss of water in a cell

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56
Q

Define effective osmolarity

A

the total concentration of impermeable solutes

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57
Q

Define hypertonic, hypotonic or isotonic

A

isotonic= solution has same concentration as the cell= not net mouv. of water

hypertonic=solution has higher concentration than the cell= cause net loss of water= cell becomes shriveled

hypotonic=solution has lower concentration than cell=net gain of water=lysed cell

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58
Q

Define osmoregulation

A

control of water balance
ex: paramecium with contractile vacuole

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59
Q

What happens to plant cell when it is place in isotonic solution

A

becomes flaccid

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60
Q

What happens to the plant cell when it is placed in hypertonic solution

A

becomes plasmolysed aka shriveled

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61
Q

What happens to the plant cell when it is placed in hypotonic solution

A

it becomes turgid so normal

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62
Q

Describe active transport

A

when solutes moves against concentration gradient (needs atp)

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63
Q

Is active transport spontaneous

A

no

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64
Q

Whats the difference between primary active transported and facilitated diffusion

A

active transport goes against concentration gradient
faciliated diffusion follows concentration gradient and is driven by the gradient from active transport

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65
Q

Whats an electrogenic pump

A

Pump that generate a voltage

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66
Q

Whats the main electrogenic pupm in animals

A

Sodium Potassium ATPase

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67
Q

Define electrochemical gradient and how they’re made

A

different net charges on each side of the membrane and concentration gradient that’s caused by an ion pump (active transport)

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68
Q

What is the membrane potential of a cell

A

voltage difference across the membrane

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69
Q

What processes do electrochemical gradients drive

A

cellular respiration, transmission of nerve impulses and muscle contractions

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70
Q

Describe secondary active transport

A

takes advantage of the concentration gradient created by prijary to drive the diffusion of more useful molecule (against its gradient)

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71
Q

Give an example of secondary active transport in plants and animals

A

animals: Glucose/Na+ symporter (in intestine)
in plants: Sucrose-H+ cotransporter

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72
Q

Why are membrane potential important

A

it favors the passive transport of cations/anions

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73
Q

Whats the difference between uniporter, symporter, anti porter

A

uniporter: carrier protein for one solute

symporter: carrier protein for 2 solutes that goes in 1 direction

antiporter: carrier protein for 2 solutes, go in opposite directions

74
Q

When is bulk transport utilized by the cell

A

when more than 3-4 molecules are trying to cross at once

75
Q

What are the 2 methods used in bulk transfer and when are they used

A

exocytosis (to leave the cell)
endocytosis (to enter the cell)

76
Q

What is bulk transport

A

Crossing membrane via vesicles , energy demanding process

77
Q

Whats the difference between constitutive and regulated bulk transport

A

regulated: in response to a specific signal

constitutive: vesicles are continuously transporting solutes in/out

78
Q

Whats the difference between exocytocysis and endocytosis

A

exocytosis:active transport

endo: passive transport

79
Q

Describe endocytosis

A

endo: uptake of substance via 3 processes
phagocytosis=PM engulfes solute and becomes a vesicle which fuses with a lysosome for digestion
pinocytosis: non specific uptake of extracellular fluid
receptor mediated endocytosis: triggered by ligan binding to receptor

80
Q

True or false
All 3 processes of endocytosis are selective

A

False on receptor mediated endocytosis

81
Q

Give an example of bulk transport

A

Pancrease when it delivers insuline

82
Q

Define cell-cell signaling

A

how cells receive messages from surrounding cells/environment

83
Q

What molecules control cell signalling

A

proteins

84
Q

Why is cell signaling important in organisms

A

Cells must communicate, allows them to form tissues/organ and perform other functions

85
Q

Give 2 examples of cell-signalling in multicellular organisms

A

pheromones= chemicals released in environment for reproduction/marking territory

plants release chemicals when attacked to alert neighbouring plants

86
Q

What is quorum sensing

A

cell-signaling allows coordination whithin a population of bacteria (they work as one)

87
Q

What is releases in quorum sensing and what responses does it trigger

A

autoinducers molecules are released and can trigger 4 kinds of response:
Sporulation, exchange od DNA, virulence, biofilm production

88
Q

What are the different kinds of local cell signaling

A

through cell junctions
Surface receptor
Paracrine signaling
Synaptic signaling

89
Q

What is local signaling

A

chemical signaling with immediate neighbouring cell.

90
Q

What type of signaling is involved in log distance

A

endocrine (hormones)

91
Q

Describe cell signaling through cell junctions

A

adjacent cells communicate directly by tranfering signaling molecules through their junctions (gap junctiopn and plasmodesmata)

92
Q

Describe cell signaling through surface receptors

A

binding of a surface marker to specific receptor of another alters the activity of a cell

93
Q

Describe cell signaling through paracrine signalling

A

cell releases local regulator that travel in ECM to nearby cell (short distance between secretory and target cells)
uses exocytosis

94
Q

Describe cell signaling through synaptic signalling

A

neurons communicate through neurotransmitters: chemical messengers that travel through synapses

95
Q

Describe cell signaling through endocrine signalling

A

hormones regulate activity of cells, tissue, organs= impacte the whole organism
importnat to have hormone selectivity

96
Q

What is hormone selectivity

A

Hormone can only affect the activity of a cell if they bind to their specific receptors

97
Q

List all stages of cell signaling

A

reception
transduction
response
signal deactivation

98
Q

Describe all stages of cell signaling

A

reception: binding of ligand to receptor of target cell
transduction: Message is transmitted and amplified
Response: Target cell’s alters its activity
Signal Deactivation: Signal is turned off

99
Q

Describe stage 1 of cell signaling

A

the ligan bind to receptor inside or oustide of the cell and triggers a conformational change in protein receptor= this change activates the protein and allows ligand to interact with molecules in cytoplasm

100
Q

What are the 2 types of signaling molecules

A

water-soluble: amino-acid based and hydrophilic= cant diffuse through membrane= receptor on surface

lipid soluble: steroid/thyroid based and hydrophobi= diffuse throgh membrane abd bind in cytoplasm/nucleus receptor
involved in gene expression

101
Q

What are the 2 types of signaling mechanism

A

1-Cell surface signaling
2-Intracellular signaling

102
Q

Describe the purpose of signal receptor

A

undergo shape change when binding with ligand which activates receptor=
can perform many fxns when activated

103
Q

What are the 2 type cell surface receptor

A

GPCRs and RTKs

104
Q

Compare intracellular and extracellular receptors

A

extracellular:bind with polar molecules

intracellular: bind with nonpolar molecules

105
Q

What are GPCRs

A

g-couple receptor proteins, found in every cell and made of specific g-protein
diff structures but all have 7 transmembrane alpha helix connected by hoops

106
Q

Describe briefly the reception pathway of GPCRs

A

ligan binds to GPCR which causes a shape change in receptor. This change activates the g-protein by replacing GDP into GTP. Activated g protein diffuses through membrane to find specific enzyme, activate it and start transduction

107
Q

How do G-protein deactivate

A

they’re GTPase enzymes so they can hydrolyze GTP to GDP themselves and in consequence deactivate themselves and the enzyme

108
Q

Describe RTK’s

A

receptor tyrosine kinase enzymes that need ATP to function
catalyse the transfer of phosphate grp to another molecule

109
Q

Whats the main difference between GPCR and RTK

A

gpcr can only trigger one signalling pathway per ligand binding whereas RTKs can start up to 6 transduction cascade per ligand binding

110
Q

Describe briefly the reception pathway of RTK’s

A

RTKs are inserted in PM through alpha helix domain and present as MONOMERS
Ligand binds to one RTK and now has high affinity for other RTK with ligand= dimerize
RTK dimer complex phosphorylates the tyrosine residue to become fully activated
Enzymes recognize the RTK and bind to tyrosine =gets activated and intiates cascade

111
Q

What are second messengers

A

small water soluble molecules that used to activate other proteins
broadcast the signal quickly

112
Q

Give two examples of second messengers

A

cyclic AMP
Calcium ion

113
Q

What is a phosphorylation cascade

A

series of kinase enzymes that phosphorylate the next enzyme

114
Q

What is signal amplification

A

each step of transduction amplifies the amount molecules which makes the response detected much bigger
1 molecule to 10^8 molecules

115
Q

What are the main molecular mechanisms in signaling response

A

catalysis by an enzyme(to break molecule)
Rearrange cytoskeleton (in muscle cells)
Activate specific genes

116
Q

What are the 2 categories of sinailing response

A

nuclear and cytoplasmic

117
Q

Describe signal deactivation

A

automatic mechanisms that turn off signalling

118
Q

What are the mechanisms that allow for signal deactivation

A

Stopping the signal (prevent ligand release)
Removal of the ligand(by enzyme or by itself)
Deactivate proteins

119
Q

What is phosphodiesterase and why is important

A

enzyme that converts cAMP back to ATP to prevent ATP depleation and deactivate the signal

120
Q

What enzyme converts ATP into cAMP

A

adenylyl cyclase

121
Q

What steps can signal be deactivated

A

when g-protein leaves the enzymes
during transduction (cAMP becomes ATP)
When ligand leaves after enzyme activation

122
Q

Give an example of abnormal cell signaling

A

cancer, abnormal cell signalling in apoptosis leads to over/under activity of certain cells, homeostatis leads to diseases

123
Q

Compare aerobic, anaerobic cellular respiration and fermentation in terms of ETC/O2 use

A

aerobic: uses both ETC and O2
anaerobic: uses ETC and no O2
Fermentation: doesnt use ETC and O2

124
Q

Which of the three main metabolic processes produce the most atp

A

Aerobic cellular respiration (around 36-38 ATP per glucose)

125
Q

Which of the three main metabolic processes produce the least atp

A

Fermentation (2 atp from glycolysis only)

126
Q

What are the 2 main types of fermentation and how do they differ from eachother

A

Alcohol: 3 steps where pyruvate intermediate is converted into ethanol/ used by microorganisms in deep soils or ponds

Fermentation 2 steps where pyruvate becomes lactate/used by yeast and animal muscle cells

BOTH UNDER ANAEROBIC CONDITION

127
Q

true of false
the generation of ATP is restricted to having glucose as the reactant

A

true

128
Q

What are redox reactions

A

Reactions that involve a loss/gain of electrons

129
Q

Why are redox rxns always coupled

A

e- can not exist freely in the cell

130
Q

What does it mean when a molecule is reduced

A

the species gains electrons

131
Q

What does it mean when a molecule is oxidized

A

the species loses electrons

132
Q

Whats a reducing/oxidizing agent

A

reducing: reduces another species while being oxidized (gives electrons)

oxidizing: oxidizes another species while being reduced (removes electrons)

133
Q

Whats the difference between an electron donnor and acceptor

A

e- donnor= reducing agent
e- acceptor= oxidizing agent

134
Q

identify whats being reduced/oxidized in the overall rxn of cellular respiration

A

Glucose is oxidized into CO2
O2 is reduced to H2O

135
Q

What are electron carriers

A

species that carry electrons to transfer their energy in the cell
can easily cycle between their oxidized and reduced form

136
Q

Whats the most versatile e- carrier and is it involved with other molecules

A

NAD+ its the coenzyme of dehydrogenase enzyme

137
Q

What are dehydrogenase enzymes and how do they function

A

enzymes that reduce NAD+ into NADH by oxidizing to a substrate which releases 2 H
2H can be separated into 2H+ and 2e- = 2e- and H+ are transferred to NAD+ and one H+ is released in the cell

138
Q

Compare NAD+/FAD to NADH/FADH2

A

NAD+/FAD: oxidizing agents
NADH/FADH2 : reduced form that carry large amount of energy (temporary)

139
Q

Why are e- carriers in important during cellular respiration

A

If glucose was broken down in 1 step the energy released with be too intense. Glucose would bind automically with oxygen and provide the E of activation for combustion (woudl burn us alive)
E- carriers transfer part of that energy gradually to the ETC and oxygen

140
Q

List 3 important energy carrier in catabolic pathways of energy metabolism

A

NADH, FADH2, NADPH

141
Q

What are the main structural components of mitochondria

A

inner/outer membrane. matrix, intermembrane space and cristae

142
Q

Where does oxidative phosphorylation occur

A

inner membrane of mitochondria

143
Q

Where do H+ accumulate in oxidative phosphorylation

A

in the intermembrane space

144
Q

What are the 4 stages of cellular respiration and where to they occur

A

1-Glycolysis in cytoplasm
2-Pyruvate Oxidation (matrix)
3-Citric acid cycle(matrix)
4-Oxidative Phosphorylation(inner membrane)

145
Q

Describe how energy is harvested by ETC

A

When e- carriers from 3 previous stages reach the ETC, they are oxidized by their respective multiprotein complex which releases electrons. The electrons then travel down the ETC moving to more lectronegative complexes each time. The transfer of electrons between complexes releases energy which powers the active transport of H+ (no atp used). The electrochemical gradient will be used by ATP synthase for the synthesis of ATP (chemiosmosis)

146
Q

Why is the ETC important (what would happen if e- were transferred to O2 directly)

A

No H+gradient would be produced to power chemiosmosis and cell would burn

147
Q

Summarize glycolysis

A

process where glucose in broken in half to make pyruvate. Happens in 2 stages, investement where 2 ATP are used to phosphorylate glucose and an intermediate( with enzymes hexokinase and PFK) and pay off where G3P from investement is oxidized to make NADH (by dehydrogenase) and its intermediate are phosphorylated to make 2 ATP molecules (with enzymes phosphoglycero kinase and pyruvate kinase)
All atp are made by substrate level phosphorylation
In total (per glucose): 2 NADH, 2 net ATP

148
Q

Summarize pyruvate oxidation

A

Pyruvate enter matrix and its carboxyl group is removed, which releases CO2, what remains is oxidized by dehydrogenase to make NADH. Lastly coenzyme A bind with the remainder to form ACetyl CoA(unstable molecule that immediatly enters Krebs)

In total (per glucose): no ATP, 2 NADH, 2 CO2

149
Q

Why is the Krebs also called citric acid cycle and why is it a cycle

A

first intermediate made is citrate
the first reactant, oxaloacetate, is regenerated in the last step (last “product”)

150
Q

Summarize the citric acid cycle

A

Acetyl CoA and oxaloacetate form citrate, with enzyme citrate synthase. The second and third intermediates are oxidized by dehydrogenase enzymes to make NADH , CO2 is also released. The fifth step is where 4 carbon compound is phosphorylated to make atp, the remainder is oxidized to produce FADH2. The last step involves the oxidation of 4 carbon compound to make NADH and regenrate oxaloacetate.

151
Q

in total per glucose what is produced after krebs

A

6 NADH
2 FADH2
2ATP
4 CO2

152
Q

whats the purpose of citric acid cycle

A

complete the breakdown of glucose

153
Q

what are the 3 characteristic of PFK that makes it a good regulator for glycolysis and cellular respiration

A

It can be inhibited by citrate, ATP and activated by AMP to maintain levels of ATP within range

154
Q

How can PFK be regulated by ATP

A

When too much ATP is produced, ATP will become an allosteric inhibitor for PFK. It will inhibit PFK’s activity to slow down glycolysis so that more ATP is being used than regenerated. this will allow ATP levels to drop back to their homeostatic range.

155
Q

What are the 2 major phases of oxidative phosphorylation and where do they happen

A

ETC and chemiosmosis, both in inner membrane of mitochondria

156
Q

Whats the function of chemiosmosis

A

Use H+ gradient from ETC to power ATP synthase in ATP production

157
Q

Whats the function of the ETC

A

To transfer the electrons from e- carriers to O2 (oxidize NADH/FADH2), which releases energy to create electrochemical gradient

158
Q

Why is oxidative phosphorylation named as such

A

ADP get phosphorylated by ATP synthase because of the oxidation of e- carriers that releases E to create an H+ gradient

159
Q

List the major component of the ETC

A

complex 1, ubiquinone (Q), complex 2, complex 3, Cytochrome C, complex 4 and oxygen

160
Q

What is the ETC made out of

A

multi-protein complexes embedded in the membrane with cofactors (non protein groups that enhance enzymatic activity)

161
Q

Describe the structure of complex 1

A

Made up of series of e- acceptor called iron-sulfur complexes/Fe-S centers, that tranfer e- to ubiquinone (last e- acceptor)
Q becomes reduce= QH2 and moves along membrane to find Complex 3

162
Q

Describe the structure of complex 2

A

Series of Fe-S centers but have a heme group that gets reduced before e- get transferred to Q

163
Q

Describe the structure of complex 3 and 4

A

Series of cytochromes (proteins with cofactor hememoity) . Last on chain CYt 3 that makes transfer to O2

164
Q

whats reduced and oxidized in complex 1

A

reduced: Q into QH2
oxidized: NADH into NAD+

165
Q

whats reduced and oxidized in complex 2

A

reduced: Q
oxidized : FADH2 into FAD

166
Q

True or false
All complexes pump H+ into the intermembrane

A

False complex 2 does not pump H+

167
Q

How many hydrogens does each complex pump in inter membrane space

A

1= 4H+
2=0
3=4H+
4=2H+

168
Q

Where is the electrochemical gradient generated by ETC

A

across inner membrane (intermembrane space is more acidic than matrix)

169
Q

Define terminal electron acceptor

A

most electronegative oxidizing agent

170
Q

What are the final electron acceptor in aerobic and anaerobic cellular respiration

A

aerobic: O2
anaerobic: nitrite, nitrate, sulfate, CO2, etc

171
Q

What major components of ATP synthase are joined by stator and rotor

A

Catalytic sites and internal rod

172
Q

What are the functions of each components of ATP synthase

A

stationary knob: rotates as H+ ions flow down their concentration gradient

Stator: embedded in membrane and maintains the know stationary

internal rod: connects know with catalytic sites and activates them

catalytic sites: undergo conformational changes as know rotates which activates the 3 active sites= 3 atp produced per rotation.

173
Q

Why is the number of ATP produced per molecules estimated

A

NADH from glycolysis is reshuffled and some protons might be given back to FADH2 or NADH.

174
Q

When are RTKs inactive

A

when they exists as monomers

175
Q

What are the 2 types of responses in cell signaling and which one is slower

A

nuclear and cytoplasmic
muclear is slower since it involve the alteration of a gene expression

176
Q

How does pyruvate enter the mitochondria (specify enzyme used)

A

outer membrane: facilitated diffusion
inner membrane: use pyruvate/H+ symporter (secondary active transport)

177
Q

How does removing O2 as last e- acceptor affect pyruvate oxidation

A

without oxygen ETC cant work which means no H+gradient is produced= the secondary active transport of pyruvate in the matrix can not happen

178
Q

What are the 3 purposes of the Kreb cycle

A

completly break down glucose
store E via oxydation (reduction of NAD+/FAD)
create ATP via substrate level phosphorylation

179
Q

Define photophosphorylation

A

when light energy from excited electron is used to make a phosphate bond in ATP

180
Q

True of false
in C4 plants only bundle sheath cells have chloroplast

A

True

Biology 2 (4 decks)

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