Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Cell Biology > Unit 3 Exam > Flashcards

Unit 3 Exam Flashcards

1
Q

What are the six ways that organisms use energy?

A

synthetic, mechanical, concentration, electrical, heat, and light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is synthetic energy?

A

making new molecules - example: growing new cells, making new macromolecules, making sugars through photosynthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is mechanical energy?

A

physically changing position or orientation of a cell part - example: cell moving in environment, chromosomes in mitosis, muscle contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is concentration energy?

A

moving molecules across a membrane against a concentration gradient - example: cells import sugars + amino acids, concentration of molecules with particular organelles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is electrical energy?

A

moving ions across a membrane against an electrochemical gradient (that takes different charges into account) - example: impulses in nerve cells, ability of electric eels to shock

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is heat energy?

A

increase in temperature in homothermic animals - example: shivering when it’s cold; heat released from chemical rxns to maintain temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is light energy?

A

production of light - example: used by bioluminescent organisms, such as fireflies and jellyfish

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Open vs closed system

A

open system - has matter and/or energy moving in or out of it
closed system - no matter or energy goes in or out (sealed off from environment)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the first law of thermodynamics?

A

law of conservation of energy - energy is neither created nor destroyed, but the energy form can change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the second law of thermodynamics?

A

in every reaction, the universe always tends towards greater disorder (entropy)
- if an increase in order occurs in the cell, it is possible because energy is added from outside

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Catabolic vs anabolic reactions

A

catabolic - biochemical pathways that break down biological molecules
anabolic - biochemical pathways that build biological molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is a metastable state?

A

molecules that can be thermodynamically unstable, but lack activation energy
- this is how cells regulate reactions, so they do not happen at random times; uses activation energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is free energy?

A

a measure of spontaneity for reactions that takes into account both energy and entropy - is measured in Gibbs - indicates if reactions are thermodynamically feasible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Endergonic vs exergonic

A

endergonic - if the change in free energy (deltaG) is positive, then the reaction requires energy
exergonic - if the change in free energy is negative, then the reaction releases energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How does a cell keep pathways active?

A

cells holds concentrations at a steady state far from thermodynamic equilibrium and reactants/products are diverted into other pathways (can use one reaction to power another)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the structure of ATP?

A

consists of a ribose, adenine base, and three phosphate groups

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How much energy is released in ATP hydrolysis?

A

deltaG = -7.3 kcal/mol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How is ATP often used?

A

it can be paired with energetically unfavorable reactions to make them run

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

phototrophs vs chemotrophs

A

phototrophs - captures the light energy from sunlight and transforms it into chemical bond energy stored in the bonds of molecules
chemotrophs - get energy by oxidizing chemical bonds in organic or inorganic molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Autotrophs vs heterotrophs

A

autotrophs - their source of carbon is CO2
heterotrophs - their source of carbon is organic molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is a redox reaction?

A

when electrons move from one molecule to another
- the molecule that loses electrons is oxidized, while the molecule that gains electrons is reduced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the common energy carriers in cells?

A

ATP and NAD+ or NADH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the general rule for energy in redox reactions?

A

the reduced version of molecules contains more energy, and oxidation of molecules releases energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Which molecule accepts electrons? NAD+ or NADH?

A

NAD+ serves as the electron acceptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is substrate level phosphorylation?
ATP is generated by the direct transfer of a phosphate group from a phosphorylated substrate onto ADP
26
What happens in glycolysis?
2 ATP molecules are hydrolyzed to add phosphate groups onto glucose, which is then split in half - the breakdown of the two halves form 2 pyruvates, which generates 4 (net 2) ATP and 2 NADH
27
What is phase one of glycolysis?
input of 2 ATP and a six carbon glucose is split into two 3-carbon molecules
28
What is phase two of glycolysis?
oxidation of the 3-carbon molecules; produces 2 ATP and 2 NADH
29
What is the third step in glycolysis?
2 pyruvate are formed and 2 ATP are produced
30
How many total steps are in glycolysis and how does it work?
there are ten total steps and each step is catalyzed by a different enzyme
31
How is ATP made in glycolysis?
substrate level phosphorylation
32
What is allosteric regulation?
regulation of a reaction by binding a regulatory molecule to a site on the enzyme that converts the enzyme into a different shape
33
What molecules negatively regulate enzymes in glycolysis?
ATP and acetyl CoA
34
Which molecule positively regulates glycolysis?
AMP
35
Why are glycolysis and gluconeogenesis different?
they follow the same 10 step process, but enzymes differ at three steps
36
What is fermentation?
occurs after glycolysis if there is no oxygen present, and reduces pyruvate to either lactate or ethanol
37
What is the purpose of fermentation?
NADH is oxidized to NAD+, which can then be used for more glycolysis
38
Aerobic vs anaerobic respiration
aerobic - the complete oxidation of glucose to produce CO2 + H2O, using O2 as the final electron acceptor anaerobic - cellular respiration where the final electron acceptor is something other than O2
39
What are the steps of aerobic respiration?
1. glycolysis 2. pyruvate is oxidized to make acetyl CoA 3. citric acid cycle 4. electron transport 5. ATP synthesis (oxidative phosphorylation)
40
Where does aerobic respiration occur?
mitochondria
41
What are the structures of the mitochondria?
outer membrane, intermembrane space, inner membrane, cristae, and matrix
42
What are the steps of pyruvate oxidation in the mitochondria?
1. a two carbon acetate group from pyruvate is linked to coenzyme A to form acetyl CoA 2. the third carbon is released as CO2 (2 CO2 per molecule of glucose) 3. NAD+ is reduced to NADH (2 NADH produced per molecule of glucose)
43
What is the process of the citric acid cycle?
1. 2-carbon acetyl CoA is linked to 4-carbon oxaloacetate to form 6-carbon citrate 2. citrate is oxidized back to oxaloacetate to generate 2 CO2 3. 2 ATP are synthesized 4. The rest of the energy is transferred to reduce NAD+ and FAD to NADH and FADH2
44
Where do pyruvate oxidation and the citric acid cycle take place in the mitochondria?
the matrix
45
How many turns does the citric acid cycle take and what are the products for one glucose?
There are two acetyl CoA for one glucose molecule, which means the citric acid cycle takes two turns. For each turn, it produces 2 CO2, 1 ATP, 3 NADH, and 1 FADH2. In total, this is 4 CO2, 2 ATP, 6 NADH, and 2 FADH2
46
What is the end result of the citric acid cycle?
all carbons are gone from glucose and has been released as CO2
47
How much energy do NADH and FADH2 release when reducing oxygen?
NADH - -52.4 kcal/mol FADH2 - -45.9 kcal/mol
48
Where does the electron transport chain take place?
integral membranes of the inner mitochondrial membrane
49
What is the electron transport chain?
electrons move from protein to protein in a series of redox reactions and each protein has a greater affinity for electrons before it finally gets to O2
50
What does complex 1 of the ETS do?
accepts electrons from NADH
51
What does complex II of the ETS do?
accepts electrons from FADH2
52
What do complex 3 do?
pass the electrons from complex I and II to complex IV
53
What does complex IV do?
passes the electrons to oxygen (in the matrix of the mitochondria) to form water
54
What happens while electrons are being transported in the ETS?
protons are pumped from the matrix to the intermembrane space
55
What are the three portions of ATP synthase?
F0 sits in the inner mitochondrial membrane F1 sits in the matrix A stalk binds the two together
56
What is the ratio of hydrogen to ATP?
3 hydrogen ions powers 1 ATP 1 NADH = 3 ATP 1 FADH2 = 2 ATP
57
Describe how ATP synthase works
As protons move through channels, the ring of C subunits turns, causing thing the g subunit to turn. g turning causes conformational changes in the B subunits, which causes the B subunits to catalyze the formation of ATP from ADP + Pi
58
How many ATP results in one full turn of g subunits?
3 ATP
59
Why is the 38 ATP yield theoretical?
yield of 38 ATP is assuming that all energy from the H+ gradient is used to make ATP, and is not powering any other processes, such as transport of ions and metabolites into the mitochondria.
60
Describe the structure of chloroplasts.
it is a triple membrane system with an outer membrane, intermembrane space, and an inner membrane. the stroma is between the inner membrane and thylakoid membrane
61
What is the thylakoid membrane?
forms disc-shaped structures called thylakoids within chloroplasts (the space inside is called the thylakoid lumen)
62
What is a photosystem?
2 special chlorophyll (reaction center) molecules that catalyze the conversion of solar energy to chemical energy - they also contain other pigment molecules, chlorophyll-binding proteins, and proteins involved in redox reactions
63
What is a light-dependent reaction?
energy transduction reactions in which light energy is captured and converted into chemical energy in the form of ATP or NADH
64
What is a resonance energy transfer?
when an excited electron moves back to ground state, released energy can be transferred to an electron in an adjacent pigment molecule
65
What is chlorophyll?
the primary energy transduction pigment
66
What is the structure of chloroplyll?
phytol side chain - hydrophobic for insertion into thylakoid membrane Porphyrin ring - absorbs light and contains magnesium (which affects the distribution of electrons) and it contains a variety of high-energy orbitals
67
What is photoreduction?
using light to add electrons onto a molecule
68
Describe the process of photoreduction in chloroplast I.
light energy is used to excite photosystem II (aka P680) electrons from PSII flow through an ETC, including b6/f, and photosystem to photosystem I (aka P700) photosystem I (P700) uses energy to excite and transfer electrons ultimately to ferredoxin
69
What does NADP reductase do?
catalyzes the transfer of electrons from ferredoxin onto NADP+ to make NADPH (in stroma)
70
What is P680?
the reaction center in chlorophylls, which absorbs light maximally at 680 nm)
71
What is P700?
reaction center for PSI and absorbs light maximally at 700 nm
72
Summarize photoreduction
electrons move from water to NADPH, through 2 photosystems and a series of electron carriers
73
Describe the flow of electrons during the light-dependent reactions.
-electrons move from water to photosystem II to P680 -electrons move in an ETC to P700 in photosystem I -electrons move down another ETC to Ferredoxin
74
Describe the hydrogen gradient in chloroplast I during photoreduction.
H+ gradient is established with a higher concentration in thylakoid lumen and lower concentration in stroma
75
What is photophosphorylation?
using energy from sunlight to make ATP
76
How does photophosphorylation work?
uses the same method as the mitochondria, only difference is, chloroplast ATP synthase protrudes into stroma, but mitochondrial DNA protrudes into matrix
77
What is the flow of electrons in the noncyclic pathway? name the products
PSII to cytochrome b6f to PSI to ATP synthase 2 ATP and 2 NADPH
78
Describe cyclic phosphorylation.
photophosphorylation that only uses photosystem I, meaning the electrons move in a cycle - this is only used to pump H+ and make ATP - no NADPH is produced
79
What is the purpose/final result of the light-dependent reactions?
light energy has been used to make ATP and NADPH
80
What is carbon fixation?
fully oxidized inorganic carbon atoms in CO2 are reduced and covalently joined to form organic compounds
81
Where does the Calvin cycle take place?
stroma of the chloroplast
82
Describe the process of the Calvin cycle.
1. CO2 is added to RuBP by the enzyme rubisco and is converted into 3-carbon molecules 2. NADPH + ATP are used to convert the 3-carbon molecules into 2 lyceeral-dihyde-3 phosphate
83
What are the stages of the Calvin cycle?
1. carbon fixation - six 3-carbon molecules are formed 2. reduction - ATP and NADPH are used to reduce the initial 3-carbon molecule to G-3-P 3. regeneration - Regeneration of the RUPB
84
How much G-3-P is used to make glucose?
1/6 of what is produced in the Calvin cycle
85
What are the 2 pathways for G-3-P pathways in carbohydrate synthesis?
converted to sucrose in cytoplasm or glucose in chloroplast stroma
86
What is rubisco?
in the calvin cycle, rubisco catalyzes the reaction where CO2 is added to RUBP and forms 2 3-carbon molecules
87
What does rubisco do for Earth?
responsible for all carbon fixation on Earth -most abundant protein on earth
88
What is wrong with rubisco?
1 out of 3 times, it adds oxygen to RuBP to create a useless product (makes a two carbon product that cannot be used and a 3 carbon product that can be used)
89
What is photorespiration?
biochemical reaction that can occur in the chloroplasts, peroxisomes, and mitochondria and returns 75% of the carbons from the 2-carbon product (which costs ATP)
90
What do C4 plants deal with rubisco's mistake?
confine rubisco to bundle sheath cells with high levels of CO2
91
What are C4 plants?
plants that grow in hot, arid, environments
92
How does photosynthesis work in C3 plants?
the Calvin cycle occurs in mesophyll cells and the first detectable product of carbon fixation is a 3-carbon molecule
93
How does photosynthesis in C4 plants?
Rubisco is only found in the bundle sheath cells and the calvin cycle occurs there. The hatch-slack cycle occurs in mesophyll cells to lower O2 concentration. The first detectable product from carbon fixation is a 4-carbon molecule
94
What is the hatch slack cycle?
-C4 solution for rubisco's mistake and carbon fixation - CO2 is attached to a carbon containing molecule to form oxaloacetate in meso cells - oxaloacetate is converted to malate, which goes to the bundle sheath cells and CO2 is released
95
What do CAM plants do during photosynthesis?
Open their stomata at night and bring CO2 and store malate in vacuoles. The CO2 is released from malate into the calvin cycle at night
96
what are CAM plants?
crassulacean acid metabolism plants found where water is very limited
97
State the evidence for the endosymbiotic theory.
M+C have their own DNA that is adjacent to the inner membrane. They have their own ribosomes and membranes that contain ATP synthase. M+C divide through binary fission and the protein transport molecules are similar
98
How did the organisms organize their nuclear genome?
some organelle genes have migrated to nuclear genes over billions of years as show by proteins being present in organelles coded by both genomes. nuclear and mitochondrial DNA are often encoded in complexes
99
How did the ETC evolve?
1. ATP dependent pumps evolved in bacteria to keep pH balanced 2. redox potential pumps that used ETCs to pump protons evolved 3. ATP dependent proton pump became reversed to produce ATP
100
What was the oxygen revolution?
because of ETCs, photosynthesis became possible, which produced oxygen causing it to increase rapidly.
101
What is ethanol?
2 carbon product of fermentation
102
What is lactate?
3 carbon product of fermentation
103
What is cytochrome b6f?
proton pump in photosynthesis
104
What is magnesium?
element found at the center of the chlorophyll molecule
105
what is rickettsia?
genus of aerobic bacteria believed to have evolved into mitochondria
106
what are cyanobactera?
photosynthetic bacteria that is believed to have evolved into chloroplasts
107

Cell Biology (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions