AP Biology Review
This guy (Bozeman) has some great videos for learning and review;
http://www.bozemanscience.com/ap-biology/
Section I
Question Type
Part A: Multiple Choice
Part B: Grid-In
Number of
Questions
63
% of Grade
Timing
90 minutes
half
6
Section II
Question Type
Long Free Response
Number of
Questions
2
Short Free Response
6
Timing
80 minutes + 10minute reading
period
half
•
For the May 2013 Exam Administration
and Beyond
Exam Content
The AP Biology Exam consists of two sections: multiple choice and free response. Both sections include questions that assess
students' understanding of the big ideas, enduring understandings, and essential knowledge and their application of these through
the science practices. These may include questions on the following:
•
•
•
•
•
the use of modeling to explain biological principles;
the use of mathematical processes to explain concepts;
the making of predictions and the justification of phenomena;
the implementation of experimental design; and
the manipulation and interpretation of data.
The exam is 3 hours long and includes both a 90-minute multiple-choice section and a 90-minute free-response section that
begins with a mandatory 10-minute reading period. The multiple-choice section accounts for half of the student's exam grade, and
the free-response section accounts for the other half.
The AP Biology Course and Exam Description, Effective Fall 2012 (.pdf/3.5MB) provides complete details about the exam
Section I: Multiple-Choice Section
Part A consists of 63 multiple-choice questions that represent the knowledge and science practices outlined in the AP
Biology Curriculum Framework that students should understand and be able to apply. Part B includes 6 grid-in questions
that require the integration of science and mathematical skills. For the grid-in responses, students will need to calculate the
correct answer for each question and enter it in a grid on that section of the answer sheet.
Section II: Free-Response Section
Students should use the mandatory reading period to read and review the questions and begin planning their responses.
This section contains two types of free-response questions (short and long), and the student will have a total of 80 minutes to
ocomplete all of the questions
.
AP Biology Review
•
Topics we will attempt to review:
•
(also be sure to read over the test taking hints in the beginning of your Cliff Notes)
Review Day 1
1. Cells – cell/plasma membrane structure
2. Photosynthesis and chloroplasts
3. Cell respiration and mitochondria
Review Day 2
4. Cell division – mitosis and meiosis
5. Molecular genetics- DNA structure and replication, protein synthesis
6. Animal structure and function- nerve impulse transmission, muscle
contraction
Review Day 3
7. Plants – repro in flowering plants, plant tropisms and hormones
8. Evolution – natural selection, speciation
Review Day 4
9. Animal repro – menstrual cycle
10. Ecology – succession, biochemical cycles
11. If time: go over the 12 labs
AP Biology Review
• AP Review Part 1
– Cell structure
– Photosynthesis and chloroplasts
– Cell Respiration and mitochondria (chemiosmosis)
AP Biology Review
• 1. Cells – cell/plasma membrane (plants, animals and
bacteria all have)
–
–
–
–
–
Phospholipid bilayer
Hydrophillic heads, hydrophobic tails
Cholesterol
Glycocalyx
Proteins
AP Biology Review
•
1. Cells – cell/plasma membrane (plants, animals and bacteria all have)
– Phospholipid bilayer, selectively permeable. Separates internal metabolic events
from external environment.
– Hydrophillic heads form outer faces, hydrophobic tails form center.
• Pass easily;
– Small uncharged polar molecules (H2O, CO2)
– Hydrophobic molecules like a O2 and hydrocarbons
• Don’t pass:
– Ions
– Large polar water soluble molecules (glucose, proteins, amino acids, nucleic acids)
– Cholesterol – provide rigidity in animal cells; in plants, sterols provide rigidity
– Glycocalyx – glycolipids and glycoproteins that coat the membrane; provide
markers for cell recognition
– Proteins scattered throughout membrane make it a fluid mosaic. Proteins can be
peripheral proteins – attach to inside or outside; or integral proteins which span
across the membrane.
•
•
•
•
•
•
Channel proteins
Transport proteins
Recognition proteins - glycoproteins
Adhesion proteins – attach to neighboring cells or provide anchors for internal filaments
Receptor proteins – binding sites for hormones and trigger molecules
Electron transfer proteins – transfer electrons from one cell to another during chemical
reactions
AP Biology Review
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• Passive processes
–
–
–
–
–
• Active processes
diffusion
facilitated diffusion
osmosis (water diffusion)
filtration
no E needed from cell
– active transport
– bulk transport
• endocytosis
– pinocytosis
– phagocytosis
– receptor mediated endocytosis
• exocytosis
– E needed from cell (ATP)
AP Biology Review
Passage of Molecules into and out of Cells
Uses
energy
Name
Direction
Requirement
Examples
Passive
Processes
Active Processes
No
Diffusion
Osmosis
Toward lower
concentration
Concentration
gradient
Lipid soluble
molecules,
water, gasses
No
Facilitated
diffusion
Toward lower
concentration
Concentration
gradient and
carrier
Some sugars
and amino acids
Yes
Active
Transport
Toward greater
concentration
Carrier
Other sugars,
amino acids and
ions
Yes
Exocytosis
Toward outside Vesicle
Macromolecules
Yes
Endocytosis
Toward inside
Cells and
subcellular
material
Vacuole
AP Biology Review
• 2. Photosynthesis
– Energy transformation in which solar energy is
converted to chemical energy
– Photosynthetic pigments
• chlorophyll a and b, carotenoids etc
• are found in the photosynthetic membranes of chloroplasts
(recall that chloroplasts are organelles - a type of plastid) inside of plant
cells.
• Absorb energy from sun – excites electrons
• Pass energy to special chlorophyll a and b molecules
(reaction center)
– P680 in PS2 and P700 in PS 1
• Eventually end up with glucose (used for cell respiration) and
oxygen, which is released to the atmosphere
AP Biology Review
AP Biology Review
Equation Summarizing Photosynthesis
Carbon Dioxide Reduced
6CO2 + 12 H2O + Energy  C6H12O6 + 6H2O + 6O2
Water Oxidized
Compare to - Cell Respiration
C6H12O6 + 6H2O + 6O2  6CO2 + 12H2O + 36 ATP + heat
Photosynthesis includes:
Light dependent reactions PS 2 and PS 1 (non cyclic photophosphorylation)
– occur in thylakoid membranes of chloroplasts.
Light independent reactions (but needs products from light dependent
reactions) – Calvin-Benson Cycle or C3 cycle – occurs in stroma of
chloroplasts.
AP Biology Review
• Non cyclic Photophosphorylation
– Uses photosystem 2 and photosystem 1(light
dependent reactions) to convert the energy in light
and in the electrons of H2O, to make ATP and
NADPH
• Cyclic Photophosphorylation
– More primitive
– Can be occurring at same time as non cyclic
– Electrons are returned to PS1 instead of making
NADPH
AP Biology Review
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e-
Reaction center chlorophyll +
Primary electron acceptor =
Reaction center
AP Biology Review
• Light Dependent Reactions
Photosystem II
– Energy from light excites
(passes energy to) antennae
complex electrons in pigments
(reaction center chlorophyll a P680) of PS2 in thylakoid
membrane of chloroplast.
AP Biology Review
• Light Dependent Reactions
Photosystem II
– Energy from antennae complex
funneled to a reaction center
chlorophyll (pigment molecule
P680).
AP Biology Review
• Light Dependent Reactions
Photosystem II
– Reaction center electrons are
passed to a primary electron
acceptor.
AP Biology Review
• Light Dependent Reactions
Photosystem II
– Then to electron transport
chain where they are passed
from carrier to carrier (such as;
ferredoxin, cytochrome), losing
a little energy each time they
are passed.
AP Biology Review
• Light Dependent Reactions
Photosystem II
– Energy from ETC used to add a
P to ADP to make ATP =
phosphorylation (hence the
name photophosphorylation).
This ATP will be used in the
light independent reactions.
AP Biology Review
• Light Dependent Reactions
Photosystem II
– Electrons passed to PS 1
– End Product of PS2 = ATP, which
will be used in light independent
reactions.
– Electrons replaced by
photolysis (decomposition by
light)
• H2O is split into H+ and ½ O2.
• These two electrons replace
the two lost from PS 2.
• H ions remain to make
gradient
• O2 lost through stomates
AP Biology Review
• Light Dependent Reactions
– Photosystem I
• Energy from light excites
electrons in antennae
complex, also receives
electron from PS II
• Energy from antennae
complex is funneled to the
reaction center chlorophyll
a (P700)
AP Biology Review
• Light Dependent Reactions
– Photosystem I
• Reaction center electrons
are passed to a primary
electron acceptor –
different one than PS2
uses.
AP Biology Review
• Light Dependent Reactions
– Photosystem I
• Primary electron acceptor
electrons are passed to a
short electron transport
chain.
• Note alternate cyclic route
(used in cyclic
photophosphorylation)
AP Biology Review
• Light Dependent Reactions
– Photosystem I
• At the end of the ETS the
2 electrons are added to
NADP+ and H+ to make
NADPH, which stores the
considerable energy still
left in the electrons.
• NADPH will be needed for
the light independent
reactions.
• Those two electrons need
to be replaced.
AP Biology Review
• Light Dependent Reactions
– Photosystem I
• Electrons replaced by
photolysis (decomposition by
light)
• H2O is split into H+ and ½ O2.
• These two electrons replace
the two lost from PS 2.
• One of the H+ provides the H
in NADPH.
• End product of PS 1 is
NADPH
• Summary Light Dependent Rx (non cyclic photophosphorylation)
– From: http://www.uic.edu/classes/bios/bios100/lectures/ps01.htm
• Summary Light Dependent Rx (cyclic photophosphorylation)
–
From: http://www.uic.edu/classes/bios/bios100/lectures/ps01.htm
AP Biology Review
Photosynthesis: H+ are pumped from stroma into thylakoid, then diffuse back
out into stroma.
Cell Respiration: H+ are pumped from matrix into intermembrane space, then
diffuse back out into matrix.
AP Biology Review
• Light Independent Reactions
– Calvin cycle, C3 cycle
– Takes place in stroma
– Fixes carbon dioxide
– Uses 6 CO2 to make one
glucose (C6H12O6) – 6 turns
of cycle.
– Can happen without light
but needs products from
light reactions.
AP Biology Review
• Light Independent Reactions
– Calvin Cycle
• CO2 reacts with 5 carbon
RuBP
• CO2 reacts with RuBP 
PGA (a 3 carbon
compound –
phosphoglyceric acid) –
need enzyme, rubisco.
Most common
protein on earth!
AP Biology Review
• Light Independent Reactions
– Calvin Cycle
• ATP and NADPH are
reduced to convert PGA
to PGAL
AP Biology Review
•
Light Independent Reactions
– Calvin Cycle
• ATP used to regenerate
RuBP from PGAL
• 2 of the 12 PGAL (3 C
molecule) generated are
used to make glucose)6C
molecule) – can also
make fructose and
maltose.
– End product of Calvin cycle
is ultimately glucose (after
6 turns, using 1 CO2 for
each turn).
Note: Diagrams start with either 1,
3, or 6 RuBPs. Starting w 1, cycle
has to go around 6x to make one
glu. Start w 6, 2x. Start w 12, 1x.
PGAL = G3P
Calvin cycle animation:
http://www.uic.edu/classes/bios/b
ios100/lectures/calvin.htm
AP Biology Review
• Three known modes of photosynthesis
– C3 plants – CO2 fixed directly to make PGA
– C4 plants – form a C4 molecule prior to the Calvin
cycle
– CAM plants – form a C4 molecule at night when
stomates can open without much water loss
AP Biology Review
• Also look at next few slides
– Only in C3 plants : Photorespiration – rubisco (RuBP
carboxylase, RuBisCO) fixes (combines it with RuBP)
oxygen instead of CO2 , cuts down on efficiency of
photosynthesis – C 4 Photosynthesis - more efficient; hot, dry climates,
sugarcane, corn, grass, plus many more, uses PEP
carboxylase
– CAM photosynthesis –almost like C4;desert plants –
can proceed during day even if stomates closed
AP Biology Review
• Photorespiration
– Understanding this helps see why C4 and CAM
systems are useful
– Rubisco can fix either O2 or CO2.
– When O2 builds up in the plant (hot/stomates closed),
then O2 gets fixed by rubisco along with CO2.
– This decreases the efficiency of CO2 fixation.
– Process uses a lot of energy without producing many
useful end products for the plant.
AP Biology Review
• Photorespiration
– Stomates are opened and
closed to regulate water exit
and CO2 entry
– Hot and dry  close to
conserve water, but then
less CO2 available and O2
builds up
– RuBP carboxylase (rubisco)
combines O2 with RuBP (for
respiration), instead of CO2
(for carbon fixation)
– Produces one molecule of
PGA and releases
(eventually) CO2
– Does not produce any
usable energy
– Only occurs in C3 plants
Photorespiration animation:
http://www.uic.edu/classes/bios/
bios100/lectures/photorespiratio
n.htm
AP Biology Review
CO2 is not produced
inside of the
chloroplast where it
could be useful
AP Biology Review
• C 3 (“regular”)
Photosynthesis
– Mesophyll cells arranged in
parallel layers
– Mesophyll cells have well
formed chloroplasts
(bundle cells don’t)
– Only mesophyll cells carry
out photosynthesis
– Bundle sheath cells do not
have chloroplasts
– Use enzyme RuBP
carboxylase (rubisco) to fix
carbon dioxide to RuBP
first detectable molecule is
PGA
– Wheat, rice, oats
AP Biology Review
• C 4 Photosynthesis
– Mesophyll cells not parallel, instead
arranged concentrically around bundle
sheath cells
– Mesophyll cells and bundle cells have
chloroplasts
• Mesophyll cells use enzyme PEPcase
(has little attraction to oxygen)to fix
carbon dioxide to PEP  first
detectable molecule oxaloacetate, a 4 C
molecule.Needs energy.
• PEPcase has less attraction for O2 than
RuBP.
• CO2 passed to bundle cells where it
enters the Calvin cycle.
– In hot, dry climates have a rate of
photosynthesis 2-3X higher than C3
plants would – no photorespiration
– Corn, sugarcane, Bermuda grass
– No photorespiration – PEPcase does
not combine with CO2, so CO2 still
delivered to the bundle cells
AP Biology Review
AP Biology Review
• CAM Photosynthesis
– Crassulacean acid
metabolism
– Happens in most succulent
plants
– During night use PEPCase
forming C 4 molecules (like
C4 photo) which are
stored in vacuoles in
mesophyll cells
– During day (when ATP and
NADPH are available)– C 4
molecules are released to
the Calvin cycle
– Open stomates only at night,
conserving water, but limits
CO2 available  less
photosynthesis
AP Biology Review
C4 and CAM animation:
http://www.uic.edu/classes/bios/bios100/lectures/c4.htm
AP Biology Review
• 3. Cell Respiration
AP Biology Review
• Cell Respiration
– Uses energy from glucose to make ATP
– Reaction is just the opposite of photosynthesis
• 6CO2 + 12H2O + Energy  C6H12O6+ 6H2O+ 6O2
• C6H12O6 + 6H2O + 6O2  6CO2 + 12H2O + 36 ATP + heat
– Three processes:
• Glycolysis
– Occurs in cytoplasm
– Can proceed without oxygen (anaerobic)
• Krebs Cycle (and transition reaction)
– Occurs In mitochondria-matrix
– Needs oxygen (aerobic)
• Electron Transport System and Oxidative Phosphorylation
– Occurs in mitochondria-cristae membrane
AP Biology Review
• Cell Respiration
– Step 1: Glycolysis
•
•
•
•
First step in respiration
Occurs in cytoplasm
Doesn’t require oxygen
Splits glucose into two
pyruvic acid molecules
• Net gain of 2 ATP
(substrate level
phosphorylation) and
2NADH
AP Biology Review
• Cell Respiration
– Step 2a: Transition
Reaction
• Connects glycolysis to
Kreb’s Cycle
• Pyruvate  acetyl CoA,
which enters Krebs
cycle
• Produces 1 NADH and 1
CO2
• Takes place in matrix of
mitochondria
AP Biology Review
AP Biology Review
• Cell Respiration
– Step 2b: Kreb’s Cycle
• Series of reactions in a
repeating cycle, takes place in
matrix of mitochondria
• Does need oxygen (aerobic)
• Starts with acetyl CoA
• Each “turn” of the Krebs cycle
produces
– 1 molecule ATP
– 2 molecules of CO2
– 4 pairs of hydrogen atoms
(most of energy from glucose
carried here)
» Hydrogen atoms will
later be picked up by
NAD+ and FAD to make
NADH2 and FADH2
AP Biology Review
• Cell Respiration
– Step 3: Electron Transport
System (oxidative
phosphorylation)
• Takes place in the cristae of
mitochondria
• Most of energy of cell
respiration is produced here
• Series of protein molecules
in membrane
• NADH + H+ and FADH2
deliver H+ and electrons to
system
• Ultimately ATP is formed (by
chemiosmosis)
– 3 for each NADH
– 2 for each FAD
AP Biology Review
• Cell Respiration
– ETS (cont)
• Oxygen is the final H+
and electron acceptor
• ½ O2 combines with
2H+ and 2 electrons to
make water
• Ultimately 36 ATP are
formed by cell
respiration
AP Biology Review
• Cell Respiration
– Chemiosmosis
• Electrons from NADH
and FAD lose energy
as they pass along the
ETC
• That energy is used to
phosphorylate ADP 
ATP
• Chemiosmosis is how
that occurs
AP Biology Review
• Chemiosmosis
– Electrochemical gradient of
H ions used to produce
ATP
– Of the 36 molecules of ATP
produced from one
molecule of glucose (being
completely metabolized), 32
come from electron
transport system’s oxidative
phosphorilation.
AP Biology Review
• Chemiosmosis
– Electrons from NADH (and
FADH2) enter ETS in cristae
membrane of mito
– H+ from NADH and FADH2 are
pumped from matrix to
intermembrane space
– Creates a pH, chemical and
electrical gradient that forces H+
to flow through ATP synthase
complex back into matrix
– Protons passing through the
complex provide the energy to
add P (phophorylate) to ADP
making ATP, which then flows
through an ATP channel protein
into intermenbrane space, then
out of the mito
AP Biology Review
• Chemiosmosis
– Electrochemical gradient of
H ions used to produce
ATP
– Of the 36 molecules of ATP
produced from one
molecule of glucose (being
completely metabolized), 32
come from electron
transport system’s oxidative
phosphorilation.
End Part One