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Biology 1 ReKaps
Lesson Book Pages 139-168
Review Homework for Biology 1
Reproductive System and Development Test 1
Generalized Eukaryotic Cell Test 1
Microbiology Test 1
Biology Subject Tests 1-3
Preview Homework for Physics 2
Physics Review Notes Chapters 4, 6-9
Thermodynamics Workshop and Quiz
Magnetism Workshop and Quiz
DC and AC Circuits Workshop and Quiz
Physics Foundation Review Unit 2
Contents
Science ReKap ............................................................................................................... 1
Passage I ........................................................................................................................ 2
Membrane Traffic ............................................................................................................ 2
Enzymes ......................................................................................................................... 4
ATP and Cellular Metabolism .......................................................................................... 5
Passage II ....................................................................................................................... 6
Mitosis and Meiosis ......................................................................................................... 7
Male and Female Reproductive Systems ........................................................................ 8
Embryogenesis ............................................................................................................... 9
Genetics and Pedigree Analysis ................................................................................... 10
Passage III .................................................................................................................... 12
Science ReKap
Membrane Traffic: Cells save energy by using diffusion when transporting down a
concentration gradient, but active transport is used when transporting against the
concentration gradient.
Enzymes: Enzymes speed up processes and are specific to certain reactions so the
body can control what is being produced.
Cellular Metabolism: Glucose is broken down into pyruvate, acetyl CoA, and finally
CO2 to create energy directly as well as indirectly through electron carriers and the
electron transport chain
Mitosis and Meiosis: Mitosis creates two identical daughter cells in most body tissue,
whereas meiosis creates four non-identical gametes to allow for genetic diversity.
Reproduction: Gametes produced via meiosis come together to form a zygote, which
grows into a morula, blastula, gastrula, and eventually neurula.
Genetics: Dominant and recessive traits can be tracked by analyzing their appearance
in family trees.
This is the last session in Unit 1, so we will focus less on your passage mapping skills in
future sessions as they should be adequate at this point.
If you are still struggling with passage mapping, please let us know!
Passage I: P-142
Type: Informational
P1: SET (original eukaryote formed from one prokaryote engulfing another)
P2: evidence: mitochondria
P3: ev.: chloroplasts
P4: ev.: spirochetes (for motility, mitosis)
Question 1
Stop: wordy, involve genetic material
Think: mitochondria genome similar to prokaryote (e.g. bacteria)
Predict: small, circular DNA
Match: C
Question 2
Stop: wordy (make a good prediction)
Think: SET evidence
Predict: no eukaryotes, prokaryotes are symbiotes
Match: B
Question 3
Stop: cell processes
Think: P4
Predict: spirochetes help with motility, e.g. mitosis
Match: A
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Membrane Traffic: P-144
Plasma membrane: controls what goes in and out of the cell
 permeable molecules are small and non-polar
 non-permeable molecules are large or polar (e.g. ions)
The membrane consists of:
 phospholipids: hydrophilic head, hydrophobic tail
 proteins (carrier proteins, ion channels)
 cholesterol: for membrane fluidity
Diffusion
Moves: permeable molecules (non-polar and small) down their concentration gradient
Requires: concentration gradient; requires no E
Osmosis
Moves: water down its concentration gradient
Requires: concentration gradient (difference in osmolarity); requires no E
Tonicity/Osmolarity
Hypotonic: lower solute concentration
Hypertonic: higher solute concentration
Isotonic: same solute concentration
Note: these terms are ALWAYS relative, meaning you are comparing one thing to
another. Assume you are comparing the given object to its environment unless
otherwise specified.
Facilitated Diffusion
Moves: impermeable particles down their concentration gradient
Requires: protein channels; concentration gradient; requires no E (other than small,
initial E cost to form channel)
Active Transport
Moves: impermeable particles (polar or medium-size) against their concentration
gradient
Requires: energy
Primary Active Transport: direct transfer, uses ATP to transport, channel is an ATPase
Secondary Active Transport: co-transport (symport) or counter-transport (antiport);
pairing with transport of a different molecule down its concentration gradient to harness
that energy
Endocytosis: large material being absorbed, e.g. phagocytosis, pinocytosis
Exocytosis: large material being expelled, e.g. neurotransmitter release (packets)
 both can also be used to rapidly change size of cell because cell uses membrane
to make/absorb vesicles
P-145 Critical Thinking
1. Fish moving from salt water (isotonic environment) to fresh water (hypotonic
environment); water would rush in to fish cells
2. Increased glucose in blood (hyperglycemia) overwhelms re-absorption in
kidneys, resulting in glucose in urine. Glucose in urine causes urine to be
hypertonic, thereby absorbing more water and resulting in increased urine output.
Increased urine output results in dehydration/increased thirst/decrease in blood
pressure.
 Hyperglycemia can also result in blood becoming hypertonic, thereby
absorbing more fluid from cells/interstitium, also affecting blood pressure.
3. 3 total moles solute on left after dissociation of 1.5 M NaCl into 1.5 M Na and 1.5
M Cl versus 2 moles solute on right; water moves left, resulting in higher water
level on left.
Question 4
Stop: increase/decrease pump action (ATP use)
Think: net effect of pumping one ion out means that pump use decreases osmolarity of
cell relative to environment, slowing the rush of water into the cell
Predict: cell needs to restore decreased osmolarity relative to new environment so
needs to pump out even more solute; ATP consumption increases
Match: A
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Enzymes: P-146
Increase rate of reaction by lowering activation energy; have no effect on
thermodynamics/favorability/equilibrium of rxn
Structure:
 substrate: molecule affected by enzyme
 active site: where substrate binds
 allosteric site: binds with signaling molecules to change enzyme conformation
and therefore regulate activity
Theories of enzyme/substrate binding:
 Lock and Key: the enzyme and substrate fit together exactly (no longer the
accepted theory)
 Induced Fit: the presence of the appropriate substrate causes a conformational
change in the enzyme such that the enzyme and substrate fit together (the
accepted theory)
Reaction Energy Profiles: an enzyme changes the rate of a reaction, but not its
equilibrium point or whether it will be spontaneous or non-spontaneous
Enzyme activity is affected by pH, concentration, temperature, co-enzymes, co-factors
Note: The term “co-factor" is sometimes limited to inorganic molecules (e.g. metals),
with "co-enzyme" or "prosthetic group" referring to organic molecules that bind loosely
or tightly to their enzyme, respectively
All types bind to enzymes to help regulate activity
Question 5
Stop: graphs
Think: rate vs. pH; rate vs. temp
Predict: pepsin is in stomach, which has a low pH and is at body temp (37° C, 98° F)
Match: D
Inhibition: preventing an enzyme from binding to a specific substrate to regulate speed
of reaction and maintain homeostasis
 Competitive: inhibitor binds reversibly to the active site, sometimes temporarily
blocking the substrate from binding
 Non-competitive: inhibitor deactivates the enzyme by temporarily binding at the
allosteric site
 Uncompetitive: inhibitor binds reversibly to a site which only becomes available
after the substrate has bound to the active site of the enzyme
 Irreversible: inhibitor binds permanently to active site or otherwise destroys the
enzyme
Negative Feedback: inhibition of a reaction pathway due to accumulation of a product or
intermediate produced by that same pathway
 Enzymatic pathways – inhibited competitively or non-competitively
 Hormonal pathways – release of hormone inhibited
Positive Feedback: up-regulation of a reaction pathway due to accumulation of a
product or intermediate produced by that same pathway
 rare in the human body due to potential to disrupt equilibrium and result in overproduction
 examples: oxytocin (causes uterine contractions); platelet activation (causes
blood clots)
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ATP and Cellular Metabolism: P-148
ATP is composed of 3 negative phosphate groups forced together, creating high energy
bonds that RELEASE energy when broken, unlike normal chemical bonds
Glycolysis is the anaerobic breakdown of glucose (6C) to 2 molecules of pyruvate (3C).
 occurs in the cytosol
Anaerobic metabolism occurs in the absence of O2 and results in 2 ATP per glucose
Fermentation generates lactic acid in muscle cells or ethanol in yeast in order to
regenerate NAD+ for further glycolysis
Aerobic respiration occurs in the presence of O2 and results in 36 ATP per glucose.
Pyruvate decarboxylation is the conversion of pyruvate (3C) to acetyl CoA (2C).
 occurs in mitochondrial matrix (requires 2 ATP to transport both pyruvates)
Acetyl CoA (2C) enters the Krebs cycle to generate GTP (ATP), NADH, and FADH2,
leaving all carbon as CO2
 occurs in the mitochondrial matrix
Electron transport chain (ETC) uses oxygen as the final e- acceptor.
 ETC occurs on the inner mitochondrial membrane.
 NADH (x10) creates 3 ATP for a total of 30
o NADH interacts with cytochrome complex I and moves to III and IV
 FADH2 (x2) creates 2 ATP for a total of 4
o FADH2 has lower energy electrons so can only interact with cytochrome
complex II (no resultant ATP) and moves to III and IV
*Note: You are NOT expected to know all the details of the individual rxns on page 150,
only general ideas! Focus mainly on what happens to the carbons and where the
energy comes from*
P-151 Question 6
Stop: enzymes in cellular metabolism
Think: last step = ETC
Predict: oxygen is receptor of eMatch: D
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Passage II: P-152
Type: Experimental
P1: background on ETC
P2: Exp 1: mitoch isolated; ADP added
Fig1: results: ADP added is prop. to O2 consumed
P3: Exp 2: inhibitors added
Fig2: results: inhibition
Question 7
Stop: times
Think: lowest aerobic respiration since zero acetyl CoA production if no O2 present
Predict: latest time with oxygen concentration closest to 0
Match: D
Question 8
Stop: concentrations
Think: directly proportional relationship from graphs (see below)
Predict: 1.5 - 0.5 = 1.0
Match: C
Graph shows adding 0.6 µmol ADP results in 0.25 µmol O2 being used for a ratio of 0.6
to 0.25
If 1.2 µmol ADP is added, this will cause a drop in the same ratio; since twice as much
ADP is added, twice as much O2 is used: 1.2 µmol ADP → 0.5 µmol O2 drop
1.5 µmol O2 µmol is available and 0.5 µmol O2 is used, then 1.0 µmol is left
Note: be careful when reading any graph since exact data points might be difficult to
read, so be both careful and flexible
You could have also used the first ADP administration of 0.3 ADP and gotten a similar
ration of 0.3 to 1.5, which would have worked as well
Question 9
Stop: molecules
Think: ox. phos. only occurs in aerobic respiration
Predict: Needs O2, NADH, FADH2, ADP, inorganic phosphate
Match: A
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Mitosis and Meiosis: P-155
Cell Cycle: process by which replication occurs
 cell spends 90% of its time in interphase (G and S); 10% in mitosis
 G (Gap) phases: growth
o Go: exiting of cell cycle, can be permanent or temporary
 S (Synthesis) phase: doubling of DNA
Sister chromatids – exact duplicates attached together via the centromere, which has
kinetochores where spindle fibers will attach
“Chromosome” may be used to refer to either the single chromatid or to the pair of sister
chromatids attached at the centromere
Mitosis: cell division with preservation of chromosome number
Phases (PMAT):
Prophase: nucleus degrades, chromosomes condense, centrioles align within
centrosomes
Metaphase: sister chromatids (2) are aligned by spindle fibers from centrioles on
metaphase plate
Anaphase: sister chromatids are pulled apart
Telaphase: cytokinesis, nuclei reformed
Meiosis: cell division with halving of chromosome number
Phase differences:
Prophase I: crossing over occurs
Metaphase I: homologous pairs are aligned (4)
Anaphase: homologous pairs are pulled apart, leaving sister chromatids together
Telaphase: still occurs as in mitosis (even though meiosis II will follow, nuclei are still
briefly reformed)
Meiosis II is nearly identical to mitosis but starts with 1/2 the number of chromosomes
(haploid).
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Male and Female Reproductive Systems: P-156
Spermatogenesis: classic meiosis forming four gametes (spermatids), which mature
into sperm through spermiogenesis by growing a tail and removing excess organelles
and cytoplasm
Pathway of sperm: SEVEn UP
Seminiferous Tubules
Epididymis
Vas Deferens (Ductus Deferens)
Ejaculatory Duct
(nothing)
Urethra
Penis
Oogenesis: all primary oocytes have already been produced at birth and have entered
meiosis, becoming arrested at prophase I
Once monthly after menarche, ~ one ovum reenters meiosis, continuing until arresting
at metaphase II
Meiosis quickly finishes if ovum is fertilized
P-157 Question 10
Stop: numbers
Think: 1 mutant and 1 normal chromosome will both be replicated
Predict: 2 mutants, 2 normal, 4 total
Match: B
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Embryogenesis: P-158
Fertilization: joining of ovum and sperm
Development: zygote → morula → blastula (implantation occurs at this stage) →
gastrula
Differentiation: one-way process in which cells are specialized by turning on some
genes and off others
 Induction is the process during which chemical messages are sent from one cell
to determine the differentiation of another cell.
o e.g. development of eyes (optic vesicles from neural tube induce formation
of lens from epithelium, which in turn induces optic vesicles to develop into
retina)
Note: when looking at the images on P-158 you are looking down at the embryo; the
head would be coming out of the page at you and the feet would go into the page.
Totipotent (omnipotent) cells are undifferentiated and can develop into any cell type,
including the outside layers of the embryo, such as the placenta
Pluripotent cells are mostly undifferentiated and can form any of the 3 primary germ
layers but not the outer layers of the embryo
Primary Germ Layers:
 Ectoderm: “attract-o-derm” (anything that would attract you to someone else)
 Endoderm: “endernal” organs (most internal organs)
 Mesoderm: “means-o-derm” (the means to get something from one place to
another, e.g. the circulatory system is the means for blood to get around,
muscles are the means for the skeleton to get around)
Question 11
Stop: primary germ layers (not A)
Think: circulatory, excretory (systems involving extensive motion)
Predict: means-o-derm
Match: D
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Genetics and Pedigree Analysis: P-160
Allele: any variation of a gene
 Dominant: always expressed; expressed in a heterozygote
 Recessive: only expressed in the absence of the dominant; not expressed/silent
in a heterozygote
Genotype: genetic makeup
Phenotype: expressed genes, physical traits
Pedigree Key
 ppen square: unaffected male
 ppen circle: unaffected female
 filled square: affected male
 filled circle: affected female
 half-filled: carrier
Autosomal Recessive: Rr x Rr
 CAN skip generations
 pedigrees without skipping can be autosomal recessive, too
Autosomal Dominant: Rr x rr
 CANNOT skip generations
P-161 Is This Autosomal Recessive?
Might or might not be; we have no way of knowing!
*Note: you can prove recessivity by generational skipping; not skipping does not prove
anything!*
Remember: prevalence does not equal dominance
Sex Linked Recessive: XY x XXc
 affects more males than females
 can skip generations
Sex Linked Dominant is uninteresting; behaves similarly to autosomal dominant
Y-linked is rare; every male is affected and females never are
Punnett Square:
Write maternal genotype on top, paternal genotype on side with one allele per section
Fill in alleles down columns and across rows.
Example: AB x O
0% OO, 50% AO, 50% BO, 0% AB
P-162 Critical Thinking 1
4 possibilities: 1 affected, 2 carriers, 1 unaffected
 offspring is not shaded so cannot be affected
 2/3 of remaining options are carriers
Penetrance: how much genes actually affect phenotype (versus environmental factors)
 many genes provide a range and environment dictates where in that range an
individual falls
o e.g. height: genes vs. nutrition
 0% = no genetic influence
 100% = no environmental influence
P-162 Critical Thinking 2
i) Sex-linked recessive due to more males affected, generation skipping
ii) Females can be carriers and should be tested. Males do not need to be tested
because they cannot be carriers; would either display trait or have no disease alleles.
iii) Gen4 male has 25% chance of being affected. (There is a 50% chance this male’s
mother is a carrier and a 50% chance that mother would pass the trait to the male.
When outcome depends on two or more probabilities, multiply those probabilities
together: 1/2*1/2 = ¼ = 25%)
iv) Gen4 female has 25% chance of being a carrier. (see above reasoning)
Chromosomal Mutations: missing/extra genetic material, usually results in a non-viable
embryo, depending on what is duplicated and how much
Disjunction: process by which sister/homologous chromatids are separated
Non-disjunction: chromatids are not all separated equally, resulting in one gamete with
n-1 chromosomes and one gamete with n+1 chromosomes

can also be partial non-disjunction where only a piece or arm of a chromosome is
improperly separated
Monosomy: only 1 copy of a chromosome
 only viable full monosomy is monosomy X (Turner Syndrome)
 some partial monosomies are viable (e.g. 5p deletion of cri du chat syndrome)
Trisomy: 3 copies of a chromosome
 can be viable if in sex chromosomes (e.g. XXY/Kleinfelter; XXX/Triple X)
 can be viable with Trisomy 21 (Down Syndrome)
 other trisomies can be viable but often result in death during childhood (e.g.
Trisomy 18 (Edwards syndrome) and Trisomy 13 (Patau Syndrome))
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Passage III: P-164
Type: Informational
P1: chromosomal abnormalities (bad)
P2: structural problems, translocation Types (balanced/unbalanced; stable/unstable)
P3: numerical abnormalities.
P4: trisomy/monosomy examples
Table 1: spontaneous abortions and chromosomal abnormalities
Table 2: frequencies of trisomies
Table 3: frequencies of sex chromosome abnormalities
Fig 1: Robertsonian translocations
Question 12
Stop: parts of DNA
Think: unstable translocation = P2; cannot undergo cell division
Predict: only centromere is directly involved in mitosis
Match: A
Question 13
Stop: errors
Think: partial trisomy = structural problem = P2; three copies of only some genes
Predict: additional information = unbalanced
Match: B
Question 14 (this is pseudo-discrete)
Stop: wordy, similar
Think: Down Syndrome = trisomy 21
Predict: trisomies come from nondisjunction
Match: C
Question 15
Stop: gametes A, B, C, D
Think: normal = 1 copy 14, 21
Predict: A is normal, B still has normal amount of genetic material, rest do not
Match: B (A and B)
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