Exam 2 Flashcards
resolving power
ability of the microscope to show two objects as separate
light micrographs for…
viewing living cells
Used to explore structures & functions of cells
electron microscope
electron microscope can magnify x______ and distinguish between objects ___ nm apart
100,000
0.2
examines cell surfaces
scanning electron microscope
examines inside of cells
transmission electron microscope
cell theory
all living things are made of cells & all cells come from other cells
first described cells
Robert Hooke
prokaryotic organisms
bacteria & archaea
prokaryotes appeared ____ million yrs ago
3.5
contains DNA in prokaryote
nucleoid
sticky coating over prokaryote
capsule
eukaryotes appeared ___ million yrs ago
2.1
3 features common to prokaryotes & eukaryotes
plasma membrane
DNA
ribosomes
composition of ribosome
protein & rRNA
system of organelles connected to nuclear envelope
endomembrane system
components of endomembrane system
ER
Golgi
lysosomes
vesicles
vacuoles
function of RER
produce membrane proteins & secretory proteins - packages proteins into transport vesicles
function of SER
produces lipids, including steroids - metabolizes carbs - helps liver detox circulating drugs
function of Golgi
receives, refines, stores, sorts & distributes chemical products - uses transport vesicles to package products
function of lysosomes
sac of digestive hydrolytic enzymes - break down proteins, polysaccharides, fats, nucleic acids - involved in food digestion & recycling
function of contractile vacuole
pump out water to maintain osmotic pressure - found in protists
function of central vacuole
store nutrients, absorb water, may contain pigments or poisons, and help maintain cell shape - found in plants
thick substance inside mitochondria
matrix
thick fluid within chloroplasts
stroma
drums made of thylakoids
grana
hollow discs containing pigments
thylakoids
responsible for similarities between mitochondria & chloroplasts
endosymbiosis
function of cytoskeleton
(1) Provides mechanical support, (2) maintains cell shape & (3) provides movement for the cell & its molecules/organelles
microfilaments
thin & solid - aid in muscle movement (actin & myosin)
intermediate filaments
structural support, hold organelles in place
microtubules
straight & hollow - guide movement of cells, cilia, flagella & chromosomes during division
cell wall composed mainly of…
cellulose
function of middle lamella
holds neighboring cells together because it is continuous with cell walls
middle lamella includes…
pectin
4 components of cell membrane
- Phospholipid bilayer
- Proteins
- Cholesterol
- Carbohydrates
turgid state
plants require hypotonic environment
3 steps of cell signalling
reception, transduction, response
cell respiration equation
C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP + heat
substance loses electrons
oxidation
substance gains electrons
reduction
electron donor
reducing agent
electron acceptor
oxidizing agent
during cell respiration, glucose is _______ and O2 is _______
oxidized
reduced
STEPS OF GLYCOLYSIS
-
Energy investment phase
- 1 ATP used to produce glucose 6-phosphate
- Fructose-6 phosphate created
- 1 ATP used to create 1,6-biphosphate
- molecule split into G3P or DHAP
-
Energy payoff phase
- G3P & DHAP converted to 1,3-biphosphoglycerate (2 NADH produced)
- phosphates taken from each molecule to phosphorylate 2 ADP
- Water loss phase — 2 more ADP phosphorylated & 2 pyruvates formed
net gain of glycolysis
2 ATP
2 NADH
STEPS OF PYRUVATE OXIDATION
- pyruvates converted to acetyl coenzyme A
- release of CO2
- produces 2 NADH & 2 H+
overall steps of cell respiration
- glycolysis
- pyruvate oxidation
- citric acid cycle
- oxidative phosphorylation & chemiosmosis
gain of pyruvate oxidation
2 acetyl CoA
2 NADH
2 H+
there are ___ total steps of citric acid cycle
8
there are __ cycle of the citric acid cycle per glucose
2
STEPS OF CITRIC ACID CYCLE
(boiled down)
- acetyl group joins oxaloacetate, forming citrate
- next 7 steps decompose citrate back to oxaloacetate
gain of citric acid cycle (both turns)
2 ATP
6 NADH
2 FADH2
NADH drops electrons into _______ and FADH2 into _______
complex 1
complex 2
proteins electrons are transferred through
cytochromes
each cytochrome has an…
iron atom
electrons pulled down ETC in cell respiration by…
O2
energy released from ETC in cell respiration is used…
to push H+ from the mitochondrial matrix to the intermembrane space
once the proton gradient is produced in the mitochondria, they diffuse…
through ATP synthase into mitochondrial matrix
work produced by H+ gradient
proton motive force
gains of chemiosmosis
26-28 ATP
energy flow in cellular respiration
glucose → NADH → ETC → proton motive force → ATP
__% of energy in a glucose is transferred to ATP; the rest is lost as heat
34
_____ ATP made per 1 glucose
30-32
how does anaerobic respiration work?
uses another electron acceptor at ETC besides O2
how does fermentation work?
uses substrate-level phosphorylation
fermentation consists of…
glycolysis plus reactions that regenerate NAD, which can be reused by glycolysis
fermentation produces ___ ATP per glucose
2
2 common types of fermentation
alcohol
lactic acid
in alcohol fermentation, pyruvate is converted to..
ethanol
which fermentation releases CO2, and which does not?
alcohol does
lactic acid does not
in lactic acid fermentation, pyruvate becomes…
NAD & lactate
use fermentation or anaerobic respiration - cannot survive in O2
obligate anaerobes
can use fermentation or aerobic cellular respiration
facultative anaerobes
producers - survive on inorganic molecules & produce organic ones
autotrophs
use sunlight to make organic molecules
photoautotrophs
consumers - use organic material
heterotrophs
major location of chloroplasts
mesophyll cells in leaves
each mesophyll contains ____ chloroplasts
30-40
pores in leaves allowing gas exchange
stomata
photosynthesis equation
6CO2 + 12 H2O + light → C6H12O6 + 6 O2 + 6 H2O
2 stages of photosynthesis
light reactions
Calvin cycle
ATP generated in plants by __________
photophosphorylation
other terms for light
electromagnetic energy or electromagnetic radiation
wavelength
distance between crests of light waves
entire range of radiation (light)
electromagnetic spectrum
visible light wavelengths
380-750nm
“particles” of light
photons
absorb visible light
pigments
best light for photosynthesis
blue-violet and some red
key light-capturing pigment
chlorophyll-a
accessory pigments
chlorophyll-b
carotenoids
measures pigment’s ability to absorb various wavelengths
spectrophotometer
graph plotting pigment’s light absorption
absorption spectrum
action spectrum of photosynthesis first demonstrated by….
how?
Theodor W. Engelmann
Exposed different segments of algae to different wavelengths & measured O2 produced via the growth of aerobic bacteria
photosystems consist of…
reaction center complex surrounded by light-harvesting complexes
reaction center complex
association of proteins holding a pair of chlorophyll-a molecules & a primary electron acceptor
light harvesting complex
pigment molecules bound to proteins
reaction-center pigment in PSII
chlorophyll P680
reaction-center pigment in PSI
chlorophyll P700
2 possible routes for electron flow in light reactions
linear
cyclic
STEPS FOR LINEAR ELECTRON FLOW IN LIGHT REACTIONS
- photon hits pigment in PSII
- P680 excited
- electrons passed to electron acceptor, making P680+
- H2O is split to replace electrons—H+ and O2 are released into thylakoid space
- electrons fall down ETC
- energy drives pumping of protons into thylakoid space across thylakoid membrane
- protons diffuse through ATP synthase, producing ATP
- photon hits pigment in PSI
- P700 excited
- electrons fall down ETC & are accepted by ferredoxin
- NADP+ reductase reduces NADP to form NADPH
how is cyclic electron flow different from linear?
electrons cycle back from ferredoxin to the PSI reaction center via plastocyanin
bypasses PSII entirely
produces ATP, but no NADPH or O2
prevents light-induced damage from O2
gains from linear light reactions
ATP
NADPH
location of Calvin cycle
stroma
calvin cycle turns…
3 times
during Calvin cycle, CO2 becomes…
glyceraldehyde 3-phosphate (G3P)
STEPS FOR CALVIN CYCLE
-
carbon fixation
- input 3 CO2
- CO2 is fixed to RuBP by rubisco, forming 6 3-phosphoglycerates
- 6 ATP added, 6 electrons from NADPH added, 6 phosphates lost
-
reduction
- 6 3-phosphoglycerate molecules are reduced by NADPH & ATP to form 6 G3P molecules
- 1 G3P molecule exits cycle to form a sugar
-
regeneration
- remaining 5 G3P molecules (15 carbons) are reused to form RuBP
- ADP & NADP+ are returned back to light reactions
____ G3P required to form glucose
2
hot, dry conditions favor…
photorespiration
most plants are ___ plants
___ plants use photorespiration
_____ plants separate photosynthesis temporally
C3
C4
CAM
how is photorespiration different?
- rubisco adds O2 instead of CO2 in Calvin cycle, producing a 2-carbon compound
- Consumes O2 & large amounts of energy
- releases CO2
- does not produce ATP or sugar
why is photorespiration a problem?
can drain 50% of carbon fixed by Calvin cycle
what is C4 plants’ advantage
minimize cost of photorespiration by incorporating CO2 into 4-C molecules instead of 3-C molecules
2 types of cells in C4 plants’ leaves
- Bundle-sheath cells - arranged in tightly packed sheaths around veins of a leaf
- Mesophyll cells - loosely packed between bundle sheath and leaf surface
C4 plants’ process for producing sugar
- Production of 4-C molecules catalyzed by PEP carboxylase in mesophyll cells
- 4-C compounds moved into bundle sheath cells
- Calvin cycle occurs in bundle sheath cells
- CO2 is released throughout the day slowly
CAM stands for…
crassulacean acid metabolism
how do CAM plants work?
- separates time between intermediate and entry into Calvin - organic acids are released into Calvin cycle during the day
- Stomata is open only at night - closed during the day to prevent water loss
- Organic acids are stored in vacuoles
examples of CAM plants
succs
pineapples