BIOL exam 3

what body systems are involved in cellular respiration?

digestive system (food), respiratory system (O2), circulatory system (putting things where they need to be)

cellular respiration

oxidation of organic compounds (food) to obtain energy

dehydrogenation/hydrogenation

movement of H often involved in redox. electrons often accompanied by protons

redox coenzymes

NAD+—accepts 2e- and 1p+ to become NADH

FAD—accepts 2e- and 2p+ to become FADH2

both are electron carriers

aerobic respiration final e- receptor

O2

anaerobic respiration final e- receptor

some inorganic molecule

fermentation final e- receptor

some organic molecule (lactic acid, yeast, ethanol)

substrate lvl phosphorylation

attaching a 3rd phosphate to ADP to make ATP. inefficient bc limited by how much PEP is available. an enzyme acts on a substrate.

oxidative phosphorylation

complete oxidation of glucose occurs in 4 stages:

• glycolysis

• pyruvate oxidation

• krebs cycle (citric acid cycle)

• e- transport chain

glycolysis, process and products

occurs in cytoplasm. convert 1 glucose (6C) to 2 pyruvates (3C). products(net): 2 ATP, 2 NADH, 2 H2O, 2 pyruvates. (note: recall that 4 ATP are produced, but 2 are consumed.)

edosymbiosis + cellular respiration

CR happens in plasma membrane of mitochondria in eukaryotic cells. CR happens in the plasma membrane of prokaryotic cells. evidence that mitochondria was once prokaryotic cell that got engulfed. p

pyruvate oxidation, process and products

3C pyruvate oxidized to 2C acetate; binds to coenzyme A to make acetyl-coA

products (per pyruvate): 1 CO2, 1 NADH, 1 acetyl coA

krebs cycle, process and products

acetyl coA (2C) + oxaloacetate (4C) → citrate (6C). products per acetyl coA: 2 CO₂, 3 NADH, 1 FADH₂, 1 ATP, regenerate oxaloacetate

electron transport chain, process and products

1) electrons from NADH → NAD+ move to NADH dehydrogenase.

2) electrons move to ubiquonone (electrons from FADH₂ → FAD move straight to ubiquonone)

3) electrons move to bc1 complex (cytochrome reductase)

4) electrons move to cytochrome c

5) electrons move to cytochrome oxidase

6) electrons move to matrix, ½ O₂ + 2 H+ + 2e- → H2O

intermembrane more positively charged because protons released as electrons move, matrix more negative. concentration gradient from intermembrane to matrix; protons move down it via ATP synthase. ATP is generated from the movement of the protons down the cg

chemiosmosis

harvesting of energy from molecules going down the concentration gradient

theoretical and actual yield of eukaryotic cells. why are they not the same?

theoretical: 32, actual: 30. some protons don’t go through ATP synthase

inhibition of phosphofructokinase

regulates cellular respiration at the glycolysis stage; inhibited by ATP and/ior citrate

inhibition of pyruvate dehydrogenase

regulates cellular respiration at the pyruvate oxidation stage; inhibited by high levels of NADH

fermentation

in the absence of O2, reduces organic molecules in order to regenerate NAD+

lactic acid fermentation- electrons transferred from NADH to pyruvate to produce lactic acid

photosynthesis equation

6CO2 + photons + 6H2O → C6H12O6 + 6O2

thylakoids

internal membranes that contain chlorophyl

grana

stacks of thylakoids

stroma

semiliquid surrounding the thylakoid

photosynthesis occurs in 2 stages:

light dependent and light independent reactions

light dependent reactions

require light; make NADPH; capture energy from sunlight. occur in thylakoids.

1. photon of light captured by pigment molecule

2. energy transferred to reaction center; an excited electron transferred to an acceptor molecule

3. electron transport. electrons move thru carriers to reduce NADP+

4. chemiosmosis produces ATP

light independent reactions

carbon fixation; absence of light; use ATP + NADPH to make glucose from CO2. occur in stroma. includes calvin cycle

pigments absorb __________

photons

photons

light energy

shorter wavelengths = _________ energy

higher

2 pigments used in green plant photosynthesis

chlorophyll A + chlorophyll B

chlorophyll A

only pigment that can directly convert light energy → chemical energy. absorbs violet, red, and blue light. main pigment in plants and cyanobacteria

chlorophyll B

absorbs wavelengths of light that chlorophyll A does not

absorption spectrum

range and efficiency of photons a molecule is capable of absorbing

carotenoids

absorb wide rand of photons, reflect yellows and oranges

antenna complex

light harvesting complex. gather photons and feed captured light energy to reaction center

reaction center

passes excited electrons out of photosystems. chlorophyll in rc absorbs a photon, electron is excited to a higher energy lvl. oxidized chlorophyll fills its ‘electron hole’ by oxidizing water. creates O2 waste

chloroplasts have 2 photosystems:

P700- photosystem 1

P680- photosystem 2 (can generate an oxidation potential high enough to oxidize H2O)

production of additional ATP

• noncyclic photophosphorylation generates ATP, NADPH, O2

• cyclic photophosphorylation is used to produce additional ATP by short circuiting photosystem 1

carbon fixation

attachment of CO2 to RuBP to form PGA (3C sugar)

calvin cycle

1. carbon fixation (attachment of CO2 to RuBP to form PGA)

2. reduction of PGA to G3P

3. regeneration of RuBP

6CO2 + 12NADPH + 18ATP → 2G3P + 6NADP+ + 18 ADP

G3P is used to form sugars like sucrose

bacteria divide by ____________

binary fission

chromosomes are composed of

chromatin—complex of DNA, RNA + proteins

histone

like a spool for DNA ‘thread’

nucleosome

complex of DNA and histone proteins. histones positively charged and strongly attracted to negatively charged phosphate groups of DNA

karyotype

picture of chromosomes in an individual

diploid

2 sets of chromosomes

haploid

one set of chromosomes

kinetochores

attachment sites for microtubules at centromeres

eukaryotic cell cycle

interphase:

G1: primary growth phase, longest phase

S: synthesis

G2: organelles replicate, microtubules organize, prep for division

m phase:

M: mitosis. nuclear division, subdivided into 5 phases

C: cytokinesis. separation of 2 new cells

centromere

middle of chromosome where we see protein association

mitosis 5 phases

1. prophase

2. prometaphase

3. metaphase

4. anaphase

5. telophase