biology exam 2

oxidation

loses electrons

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(LEO)

reduction

gains electrons

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(GER)

NAD+ → NADH

reduction

electron transport chain

electrons are harvested from NADH and FADH2 through oxidation, electrons are shuttled down a series of transmembrane proteins, final electron acceptor is OXYGEN (which is reduced to make H2O)

chemiosmosis

when a proton gradient is used to drive energy-requiring processes, starting with one glucose molecule, 34 atp are generated

how do prokaryotes make ATP if they don’t have mitochondria

fermentation

true or false: both eukaryotic and prokaryotic cells can use fermentation

true

fermentation is a ___ process

anaerobic (no O2 required)

how much does ATP does fermentation make

a little

fermentation is used by which type of muscles

“fast twitch fiber” muscles, used for short energy bursts (sprinting/lifting weights, etc)

where does fermentation occur

the cytoplasm (no organelle required)

anaerobic fermentation pros and cons

con: very little ATP is made

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pro: occurs in complete absence of oxygen, some ATP is better than none, replenishes glycolysis

two types of fermentation

1. lactic acid
2. alcoholic

lactic acid fermentation is mostly used by

eukaryotes (muscle cells)

lactic acid steps

1. glycolysis: same process as cellular respiration (2 net ATP)
2. pyruvate processing: pyruvate is converted to lactate (lactic acid), the cause of the “burn” in muscles

how does the kinase (enzyme) make ATP?

transfers a phosphate group from a substrate to ADP

which cell types use alcoholic fermentation?

1. yeast (eukaryotic)
2. bacteria

ethanol

an alcohol, rich in energy, but often toxic to eukaryotic cells in high doses

alcoholic fermentation converts pyruvate to

pyruvate → acetylaldehyde → ethanol

what product of alcoholic fermentation can be used to keep glycolysis going?

NAD+

what are the products at the end of the anaerobic cycle

1. 2 ethanol OR 2 lactate
2. 2 ATP
3. 2 NAD+ (which can be reused in glycolysis)

what are the oxygen-dependent processes?

electron transport chain & chemiosmosis

why is fermentation the emergency backup plan?

NADH and FADH2 can donate electrons to pyruvate molecules (NADH becomes are input for fermentation and pyruvate gets reduced)

true or false: anaerobic respiration always produced less ATP than aerobic respiration

true

true or false: only prokaryotes use fermentation

false

during fermentation, what molecule is produced that is able to initiate glycolysis again?

FAD and NAD+

autotroph

use light to make food by themselves

plant food

sugars (mainly glucose)

what is photosynthesis

food producing process for plants (sugars)

what does photosynthesis do

convert energy carried by photons into chemical bond energy

photosynthesis inputs and outputs

inputs: CO2, H2O, light

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outputs: O2, sugars (storable energy)

heterotrophs

eat external food for energy

stack of thylakoids

granum

thylakoids contain __ used for photosynthesis

photopigments

photopigments

molecules that undergo chemical change when they absorb photons (light)

where are photopigments found?

thylakoid membrane

photopigments resemble a…

lipid (polar head and hydrocarbon tail)

main photopigment

chlorophyll a

accessory pigments

chlorophyll b, carotenoids

carotenoids are responsible for what

seasonal changes (leaves green → orange/red)

absorption

photons are completely absorbed (color you DON’T see)

reflected

photons are reflected (color you DO see)

transmission

photons pass directly through

light has two categories

visible light and other light

wavelength

distance between photon waves

light from shortest to longest wavelength

gamma rays, x-rays, ultra-violent, visible light, micro-waves, radio waves

the shortest wavelength has the __ energy

highest

shorter wavelengths

can damage cells & cause mutations

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(think gamma rays creating the hulk)

chlorophyll a & b

absorbs blues and reds, reflects greens

tenoidscar

absorbs all but oranges/reds, reflects oranges/reds

if a leaf is green,

green light is reflected

when a photon is absorbed

carried electrons enter an excited state

why would blue light provide the most excitation?

it has the shortest wavelength and therefore the highest energy

true or false: red and orange wavelengths of visible light have higher energy that blue and greens

false

stages of photosynthesis

1. light dependent reactions
2. light independent reactions (calvin cycle)

light dependent reactions steps

1. photosystem 2
2. photosystem 1

photosystem 2

a group of photopigments within the thylakoid membranes

photosystem 2 steps

electrons are excited, then donated to a protein called PEA, then an electron transport chain occurs

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H2O required, O2 is a waste product

ATP production via movement of protons across a membrane is called

chemiosmosis

electron transport chain

H+ protons diffuse through ATP synthetase

photosystem 1

electrons harvested from photosystem 2 are donated to neighboring photosystem 1

major difference between photosystem 1 and 2

photosystem 1 is where NADPH is produced

light independent reactions function

sustains plant life during periods of darkness (night), designed to slowly produce food to ensure survival

what products of the calvin cycle refuel the light dependent reactions

NADP+ and ADP

three stages of calvin cycle

1. carbon fixation
2. reverse glycolysis
3. replenishment of RuBP

carbon fixation

carbon from atmospheric CO2 is “fixed” onto RuBP (an enzyme) forming PGA

detailed carbon fixation

1 carbon from CO2 fixes onto RuBP - making it 6 carbons long

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6 carbon RuBP splits in half (2 sets of 3 carbon)

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creates 2 PGA per 1 RuBP (6 PGA made in total bc it starts with 3 RuBP)

reverse glycolysis

6 PGA’s from carbon fixation are reduced to produce 6 G3Ps

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outputs: glucose (food), G3P (used to replenish RuBP for carbon fixation)

why is it called reverse glycolysis?

because in glycolysis we break down sugar, but in reverse glycolysis we are making sugar

replenishment of RuBP

G3P produced in reverse glycolysis creates more RuBP for carbon fixation

if you place a plant in a room with no light, the first system to be affected is the

LDRs

if you deprive a plant of all CO2, the system that will be affected first is

the calvin cycle

where is the specific location where sugars are produced?

stroma

what are the similarities between cellular respiration and photosynthesis?

chemiosmosis, electron transport chain, ATP production, electron carrier production

proliferation

how cells are “born”

apoptosis

cell death

interphase steps

1. G1
2. S
3. G2

G1

cell growth

S

synthesis of DNA (making a copy and condensing it)

G2

more growth, centrosomes form (move to opposite poles)

homologous chromosomes

identical chromosomes from each parents

human karyotype

46 chromosomes, 23 pairs

diploid (2n)

two copies of all genes (from each parent)

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2n = 46 chromosomes

diploid examples

non-sex cells (skin cells, kidney cells, brain cells, etc)

haploid (n)

one copy of genes

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n = 23 chromosomes

haploid examples

sex cells / gametes (sperm and egg)

sister chromatids

chromosomes after they’ve been replicated, same information on each chromatid

centromere

where sister chromatids are held together

dna levels range from 3 to 6 picograms per nucleus, at which stage of the cell life cycle would you predict a cell to have 6 picograms?

G2

mitosis

production of two identical progeny cells from a single parent cell (cell division of non-gamete cells in eukaryotes)

major roles of mitosis

organismal growth, development, tissue renewal & repair, reproduction

__ are separated through mitosis

sister chromatids

genome

the complete set of genes or genetic material present in a cell or organism

stages of mitosis

(interphase)


1. prophase
2. prometaphase
3. metaphase
4. anaphase
5. telophase/cytokinesis

prophase

chromosomes begin condensing, spindle fibers emerge from centrosomes

spindle fibers

cytoskeletal molecules that will attach to chromosomes at the centromere pull chromosomes apart

prometaphase

nucleus membrane dissolves (allows us to have access to chromosomes), centromeres arrive at cell poles

metaphase

chromosomes line up at the metaphase plate

anaphase

sister chromatids pulled apart by spindle fibers

telophase and cytokinesis

DNA begins to decondense, cell divides, nucleus membrane reforms (1 cell → 2 cells)