organelles part 2 Flashcards
general characteristics of lysosomes
digest macromolecules
- can degrade all cellular components
- contain acid hydrolyses
resident proteins modified by Golgi apparatus and trafficked via vesicles
what is the structure of lysosomes
heterogenous –> have vesicles leaving and coming in which constantly changes shape
non uniform structure
delivering materials to endosomes
endocytosis - brings in part of membrane phagocytocysis - brings in larger particles autophagy - old organelles are targeted
what organelle acts as a lysosome in plants and fungi?
vacuoles
- contain hydrolytic enzymes
- also store nutrients and waste
different functions for different vacuoles
characteristics of peroxisomes
not part of endomembranous system
single membrane organs
perform oxidation reactions
how do peroxisomes convert hydrogen peroxide into something less toxic?
peroxidation
- convert h202 to h20
what is Zellweger syndrome
peroxisome disorder
causes abnormalities in brain, liver, kidneys and other physical deformities
general characteristics of mitochondria cell cycle
maintain own DNA, but incomplete
require proteins from cytosol
replication resembles bacteria
mitochondria: outer membrane
fatty acid breakdown
adding or removing carbons
inner membrane
site of electron transport chain
site of oxidative phosphorylation
matrix
cite of citric acid cycle
what is glycolysis
6 carbon glucose is oxidized to 2 3 carbon pyruvate
produces little ATP
reduces electron carriers
what are the major product of glycolysis
glucose + 2NAD + 2ADP + 2P–>
2 pyruvate + 2NADH + 2H + 2 ATP
what are the names for the citric acid cycle
tricaboxylic acid cycle
citric acid cycle
krebbs cycle
what are the products of TCA cycle
1 glucose:
glucose + 10 NAD + 2FAD + 4 ADP +4P–>
6CO2 + 10 NADH + 2FADH + 4 ATP
what is the purpose of the citric acid cycle
doesn’t produce much ATP but electron carriers will down the road
what is the electron transport chain (respiration)
electrons passed through a series of pumps to terminal electron acceptor (oxygen)
creates a proton gradient
why do we need an electron transportt chain
use heat energy to do work
avoid combustion
exergonic
- number
spontaneous
favorable
endergonic
+ number
non spontaneous
unfavourable
what is the most favourable free energy
biggest number for acceptor
smallest number for donor
what is the chemiosmotic hypothesis
transfer of electrons in ETC creates a proton gradient that leads to a chemical and charge gradient
- proton motive force
what properties make up the proton motive force?
chemical gradient + charge gradient
what is the definitive experiment
demonstrated that the electron transport chain isn’t linked
in the absence of light, no proton movement and no ATP produced
how many protons are required to produce a full turn of the proton path
10 subunits = 10 protons
what is the ratio of protons to ATP yield?
4 protons per ATP
or 12 protons for 4 ATP
what are the 3 conformations of ATP synthase
Open –> allows things to move in/out
Loose–> holds ADP and Pi
Tense –> converts ADP and Pi to ATP
general overview of oxidative phosphorylation
electron transport chain pumps protons along series of pumps to ATP synthase where the movement of protons produce ATP
what are the 2 stages of oxidative phosphorylation (process of chemiosmotic coupling)
- high energy Es are used to pump H+ across a membrane
2. H+ flows down the gradient through ATP synthase
where are the protons pumped during OP and where do they go?
pumped from mitochondrial matrix and into inner membrane space
what happens if oxidative phosphorylation is uncoupled?
lose the proton gradient, lose production of ATP and cell will lose energy no matter how hard it works
what complex does cyanide inhibit
complex 4, cytochrome oxidase
uncouples oxidative phosphorylation by inhibiting this complex (stops electron chain, no regeneration of NAD+, no TCA cycle)
what is the purpose of brown fat cells and where is it found
brown fat cells purposefully uncouple OP to generate heat and couple to Thermogenin (produce heat energy)
found in infants
what is the direction of proton motive force due to membrane potential and H+ gradient
membrane potential –> flow from + to -
H+ gradient –> flow from [high] to [low]
what process is utilized during exercise
anaerobic glycolysis, fermentation keeps going NO OXYGEN
what is the net rxn of glycolysis
glucose + 2NAD + 2ADP + 2P –> 2 pyruvate + 2NADH + 2ATP + 2H
what is the net rxn of TCA
glucose + 10 NAD + 2FAD + 4ADP 4Pi –> 6CO2 + 10NADH + 2 FADH + 4ATP
what is the net rxn of oxidative phosphorylation
10NADH +10H + 2FADH + 6CO2 + 34 ADP + 24 P–> 10 NAD + 2 FAD + 2H20 +34 ATP
what is photosynthesis and where does it take place
light energy is harvested and CO2 is fixed as carbohydrates, takes place in chloroplasts of plants
how did chloroplasts arise
may have been ancient cyanobacteria taken up by a cell
what is the net rxn of carbon dioxide fixation
light + 6CO2 + 6H20 –> C6H12O6 + 6O2
what is the electron donor utilized in oxygenic photosynthesis
H20
what is the light rxn
photosynthetic e- transfer
what is the dark rxn
carbon fixation (independant of light)
where are protons pumped from and where do they go in chloroplasts
pumped from storm and into the thylakoid lumen
flow down from lumen back into storm
what is chlorophyll and what does it do
pigment embedded in the membrane, within photosystem, converts solar energy into chemical energy
why do plants use photosynthesis rather than oxidative phosphorylation?
get electrons from water, water cannot directly donate its water to anyone so it must be energized with light
not enough energy would be produced to keep cell alive based on waters low E’
what is produced when you take protons from water?
oxygenic reactions –> O2
what does photosystem I do ?
accepts electrons from PC and passes them to ferradoxin
what does photosystem II do?
removes the electrons from water and passes to MSP
what does cytochrome B do ?
receives electrons from PS II and passes to PS I
what is catabolism?
glucose is broken down into smaller molecules and reduced electron carriers and ATP (glycolysis)
what is anabolism?
ATP is used to build glucose and larger molecules
where is the electron transport chain located in the chloroplast ? where is it in the mitochondria?
chloroplast –> thylakoid membrane
mitochondria –> inner membrane
what is the Calvin cycle
cycle used by most organisms to get carbon from CO2
from 5C molecule to 3C molecules
5C molecule + 1 C = 6 C molecule –> split into 2 3C molecules
