unit 3 biology

studied byStudied by 0 people
0.0(0)
Get a hint
Hint

metabolism

1 / 97

flashcard set

Earn XP

Description and Tags

12th grade ap biology

98 Terms

1

metabolism

- all chemical reactions in an organism
- substrate -> intermediate -> intermediate -> product

New cards
2

metabolic pathways

- series of chemical reactions that either build complex molecules or break down complex molecules
- two types: catabolic, anabolic

New cards
3

catabolic pathways

release energy by breaking down complex molecules into simpler compounds (ex: hydrolysis)

New cards
4

anabolic pathways

consume energy to build complicated molecules from simpler compounds

New cards
5

energy

- ability to do work
- organisms need energy to survive and function
- a loss in energy flow results in death

New cards
6

kinetic energy

energy associated with motion

New cards
7

thermal energy

energy associated with the movement of atoms or molecules

New cards
8

potential energy

stored energy

New cards
9

chemical energy

potential energy available for release in a chemical reaction

New cards
10

thermodynamics

- the study of energy transformations in matter
- the laws apply to the universe as a whole

New cards
11

1st law of thermodynamics

energy cannot be created or destroyed, only transferred or transformed

New cards
12

2nd law of thermodynamics

- energy transformation increases the entropy (disorder) of the universe
- during energy transfers, some energy is unusable and often lost as heat

New cards
13

free energy

determines whether or not the reaction occurs spontaneously/ are energetically favorable

New cards
14

exergonic reactions

- release energy
- reaction is spontaneous
- ex: cellular respiration

New cards
15

endergonic reactions

- absorb energy
- reaction is not spontaneous
- ex: photosynthesis

New cards
16

cells and energy

- living cells have a constant flow of materials in and out of the membrane
- cells are not at equilibrium
- cells perform three kinds of work: mechanical, transport, chemical

New cards
17

mechanical work

- movement
- ex: beating cilia, chromosome movement, muscle cells contraction

New cards
18

transport work

pumping substances across membranes against spontaneous movement

New cards
19

chemical work

- synthesis of molecules
- ex: building polymers from monomers

New cards
20

ATP

- molecule that organisms use as a source of energy to perform work
- most potential energy
- couples exergonic to endergonic reactions to power cellular work
- organisms obtain energy by breaking the bond between the 2nd and 3rd phosphate in hydrolysis (ATP -> ADP)

New cards
21

phosphorylation

the released phosphate moves to another molecule to give energy (donating a phosphate)

New cards
22

enzymes

- macromolecules that catalyze (speed up) reactions by lowering the activation energy
- not consumed by the reaction
- type of protein
- names end in -ase

New cards
23

enzyme structure

acts on a reactant called a substrate

New cards
24

enzyme function

active site (area for substrate to bind)

New cards
25

induced fit

enzymes will change the shape of their active site to allow the substrate to bind better

New cards
26

enzyme catabolism

helps break down complex molecules

New cards
27

enzyme anabolism

helps build complex molecules

New cards
28

effects on enzymes

- affected by temperature, pH, and chemicals
- change in shape = change in function
- optimal conditions: enzyme will denature outside of its optimal range of temp or pH

New cards
29

enzyme cofactor

- nonprotein molecules that assist enzyme function
- inorganic cofactors consist of metals
- can be bound loosely or tightly

New cards
30

holoenzyme

an enzyme with the cofactor attached

New cards
31

coenzymes

- organic cofactors
- ex: vitamins

New cards
32

enzyme inhibitors

- reduce the activity of specific enzymes
- can be permanent or reversible

New cards
33

permanent inhibition

- inhibitor binds with covalent bonds
- ex: toxins, poisons

New cards
34

reversible inhibition

inhibitor binds with weak interactions

New cards
35

competitive inhibitors

- reduce enzyme activity by blocking substrates from binding to the active site
- can be reversed with increased substrate concentrations

New cards
36

noncompetitive inhibitors

- bind to an area other than the active site (allosteric site), which changes the shape of the active site preventing substrates from binding
- type of allosteric inhibition

New cards
37

regulation of chemical reactions

a cell must be able to regulate its metabolic pathways by controlling where and when enzymes are active and switching genes that code for enzymes on or off

New cards
38

allosteric enzymes

two binding sites (1 active and 1 allosteric)

New cards
39

allosteric regulation

- molecules bind (noncovalent interactions) to an allosteric site which changes the shape and function of the active site
- may result in inhibition or stimulation of the enzymes activity

New cards
40

allosteric activator

substrate binds to allosteric site and stabilizes the shape of the enzyme so that the active sites remain open

New cards
41

allosteric inhibitor

substrate binds to allosteric site and stabilizes the enzyme shape so that the active site are closed (inactive form)

New cards
42

cooperativity

substate binds to one active site (on an enzyme with more than one active site) which stabilizes the active form (considered allosteric regulation since binding at one site changes the shape of other sites)

New cards
43

feedback inhibition

sometimes the end product of a metabolic pathway can act as an inhibitor to an early enzyme in the same pathway

New cards
44

photosynthesis

conversion of light energy to chemical energy

New cards
45

autotrophs

- organisms that produce their own food (organic molecules) from simple substances in their surroundings
- ex: plants (specifically photoautotrophs)

New cards
46

heterotrophs

organisms unable to make their own food so they live off of other organisms

New cards
47

photosynthesis evolution

- first evolved in prokaryotic organisms
- cyanobacteria: early prokaryotes capable of photosynthesis and oxygenated the atmosphere of early earth
- prokaryotic photosynthetic pathways were the foundation of eukaryotic photosynthesis

New cards
48

site of photosynthesis

- leaves: primary location in most plants
- chloroplast: organelle location, found in mesophyll

New cards
49

mesophyll

cells that make up the interior tissue of the leaf

New cards
50

stomata

pores in leaves that allow CO2 in and O2 out

New cards
51

chloroplast structure

- surrounded by a double membrane
- stroma: aqueous internal fluid
- thylakoids form stacks called grana
- chlorophyll: green pigment in thylakoid membranes

New cards
52

photosynthesis reaction

6CO2 + 6H2O + light energy -> C6H12O6 + 6O2

New cards
53

photosynthesis stages

- light reactions (light dependent)
- calvin cycle (light independent/dark reaction)

New cards
54

pigment

- absorb visible light
- the color we see is the reflected wavelengths

New cards
55

chlorophyll a

- primary pigment
- involved in light reactions
- blue/green pigment

New cards
56

chlorophyll b

- accessory pigment
- yellow/green pigment

New cards
57

carotenoids

- photoprotection: absorb and dissipate excessive light energy that could damage chlorophyll or interact with oxygen
- yellow/orange pigment

New cards
58

light reaction

- occur in thylakoid membrane in the photosystems
- concert solar energy to chemical energy (NADPH and ATP)
- happens bc light energy (photons) is used to excite electrons

New cards
59

chlorophyll and light

1. chlorophyll absorbs a photon of light
2. electron is boosted from a ground state to an excited state
3. electron is unstable and falls back to ground state
4. releases energy as heat and emits photons as fluorescence

New cards
60

photosystems

- reaction center and light capturing complexes
- in the thylakoid membrane, there are two: PS2 and PS1

New cards
61

reaction center

a complex of proteins associated with chlorophyll a and an electron acceptor

New cards
62

light capturing complexes

pigments associated with proteins

New cards
63

photosystem 2

1. light energy (photon) causes an electron to go from an excited state back to a ground state. repeats until it reaches the P680 pair of chlorophyll a molecules
2. electron is transferred to a primary electron acceptor, forming P680+
3. H2O splits into 2e-, 2H+, and O2

New cards
64

linear electron flow

each excited electron will pass from PS2 to PS1 via ETC

New cards
65

ETC (photosynthesis)

in light reaction on thylakoid membrane

New cards
66

photosystem 1

1. light energy excites electrons in P700 chlorophyll molecules, becoming P700+
2. electrons go down a second transport chain
3. NADP+ reductase catalyzes the transfer of electrons from Fd to NADP+
4. results in NADPH

New cards
67

generation of ATP

- "fall" of electrons from PS2 to PS1 provides energy to form ATP
- proton gradient is a form of potential energy
- ATP synthase couples the diffusion of H+ to the formation of ATP

New cards
68

light reaction inputs and outputs

- inputs: H2O, ADP, NADP+
- outputs: O2, ATP, NADPH

New cards
69

light reaction summary

- water is split providing a source of electrons and protons and releasing oxygen
- light absorbed by chlorophyll drives the transfer of electron and hydrogen ions from H2O to an electron acceptor, NADP+
- NADP+ is reduced to NADPH
- generates ATP by phosphorylating ADP

New cards
70

calvin cycle

- cyclic electron flow
- uses ATP and NADPH to reduce CO2 to sugar (G3P)
- for net synthesis of 1 G3P molecule, the cycle must take place 3 times (GP -> G2P -> G3P)
- three phases: carbon fixation, reduction, regeneration of RuBP

New cards
71

carbon fixation

1. CO2 is incorporated into calvin cycle one at a time (3 times to produce 1 net G3P)
2. each CO2 attaches to a molecule of RuBP and catalyzed by enzyme rubisco
3. forms 3-phosphoglycerate

New cards
72

reduction

1. 3-phosphoglycerate is phosphorylated by ATP and becomes 1,3-biphosphoglycerate
2. NADPH donate electron to 1,3-biphosphoglycerate
3. reduces to G3P: 6 molecules of G3P are formed (1 is a net gain and the other 5 are used to regenerate RuBP)

New cards
73

regeneration of RuBP

1. 5 molecules of G3P are used to regenerate 3 RuBP
2. cycle is now ready to take in CO2 again
- 3 ATP are used

New cards
74

calvin cycle inputs and outputs

- inputs: CO2, ATP, NADPH
- outputs: G3P, ADP, NADP+

New cards
75

C3 plants problem

- photorespiration: on hot days plants close their stomata to stop water loss
- causes less CO2 to be present and more O2
- wastes energy and no sugar is produced

New cards
76

C4 plants

- stomata partially close to conserve water
- ex: corn, grasses, sugarcane

New cards
77

CAM plants

- open stomata at night and close during the day
- CO2 is incorporated into organic acids and stored in vacuoles
- during the day, light reaction occur and CO2 is released from the organic acids and incorporated into the calvin cycle
- ex: cactus, succulents, jade, pineapples

New cards
78

cellular respiration

cells harvest chemical energy stored in organic molecules and use it to generate ATP

New cards
79

cellular respiration reaction

C6H12O6 + 6O2 -> 6CO2 + 6H2O + energy (ATP and heat)

New cards
80

starch

- major source of fuel for animals
- breaks down into glucose

New cards
81

path of electrons in energy harvest

- during cellular respiration, most electrons will follow this "downhill" exergonic path
- glucose -> NADH (e- carrier) -> ETC -> oxygen

New cards
82

energy harvest

- glucose is broken down in steps to harvest energy
- electrons are taken from glucose at different steps
1. each electron taken travels with a proton
2. transfers 2 electrons and 1 proton to the coenzyme NAD+ and reduces to NADH (stores the energy)
3. NADH carries electron to the ETC

New cards
83

electron transport chain

- a sequence of membrane proteins that shuttle electrons down a series of redox reactions
- releases energy used to make ATP
- transfers electrons to oxygen

New cards
84

oxygen

final electron acceptor to make water

New cards
85

stages of cellular respiration

1. glycolysis
2. pyruvate oxidation and the citric acid cycle
3. oxidative phosphorylation

New cards
86

glycolysis

- occurs in cytosol
- splits glucose into 2 pyruvates
- two stages: energy investment, energy payoff
- input: 1 glucose
- output: 2 pyruvate, 2 ATP, 2 NADH

New cards
87

energy investment stage

the cell uses ATP to phosphorylate compounds of glucose

New cards
88

energy payoff stage

energy is produced by substrate level phosphorylation

New cards
89

pyruvate oxidation and the citric acid cycle

- if oxygen is present, the pyruvate enters the mitochondria (eukaryotic cells)
- occurs in mitochondrial matrix
- pyruvate oxidation: pyruvate is oxidized into acetyl CoA
- citric acid: acetyl CoA turns into citrate, electrons transferred to NADH and FADH2
- input (pyruvate oxidation): 2 pyruvate
- output (pyruvate oxidation): 2 acetyl CoA, 2 CO2, 2NADH
- input (citric acid): 2 acetyl CoA
- output (citric acid): 4 CO2, 2 ATP, 6 NADH, 2 FADH2

New cards
90

oxidative phosphorylation

- occurs in inner membrane of mitochondria
- ETC and chemiosmosis
- input: 10 NADH, 2 FADH2
- output: 26-28 ATP

New cards
91

oxidative phosphorylation (ETC)

- do not produce ATP directly
- creates a proton gradient across the membrane that will power chemiosomosis by using hydrogen ions to power cellular work

New cards
92

oxidative phosphorylation (chemiosmosis)

- ATP synthase: the enzyme that makes ATP from ADP + P
- uses energy from the proton gradient across the membrane
- H+ ions flow down their gradient through ATP synthase
- produces about 26-28 ATP per glucose

New cards
93

respiration without oxygen

organisms will produce ATP through anaerobic respiration or fermentation

New cards
94

anaerobic respiration

- generates ATP using an ETC in the absence of oxygen
- takes place in prokaryote organisms that live in environments with no oxygen
- final electron acceptors: sulfates, nitrates

New cards
95

fermentation

- generates ATP without an ETC
- extension of glycolysis (recycles NAD+, occurs in cytosol, no oxygen)
- two types: alcohol, lactic acid

New cards
96

alcohol fermentation

- pyruvate is converted in ethanol
- ex: yeast, bacteria

New cards
97

lactic acid fermentation

- pyruvate is reduced directly by NADH to form lactate
- ex: muscle cells

New cards
98

breakdown of lactate

- muscles produce lactate, which goes into the blood, and is broken down back to glucose in the liver
- when lactate is in the blood, it lowers the pH
- if lactate builds up and is unable to be broken down, it can lead to lactic acidosis (excessively low blood pH)

New cards

Explore top notes

note Note
studied byStudied by 57 people
... ago
5.0(1)
note Note
studied byStudied by 17 people
... ago
5.0(1)
note Note
studied byStudied by 31 people
... ago
5.0(2)
note Note
studied byStudied by 440 people
... ago
5.0(2)
note Note
studied byStudied by 28 people
... ago
5.0(2)
note Note
studied byStudied by 17 people
... ago
5.0(1)
note Note
studied byStudied by 19 people
... ago
5.0(1)
note Note
studied byStudied by 8 people
... ago
5.0(1)

Explore top flashcards

flashcards Flashcard (20)
studied byStudied by 5 people
... ago
5.0(1)
flashcards Flashcard (64)
studied byStudied by 80 people
... ago
5.0(5)
flashcards Flashcard (22)
studied byStudied by 33 people
... ago
5.0(2)
flashcards Flashcard (22)
studied byStudied by 70 people
... ago
5.0(2)
flashcards Flashcard (177)
studied byStudied by 7 people
... ago
5.0(2)
flashcards Flashcard (116)
studied byStudied by 7 people
... ago
5.0(1)
flashcards Flashcard (36)
studied byStudied by 3 people
... ago
5.0(1)
flashcards Flashcard (125)
studied byStudied by 30 people
... ago
5.0(1)
robot