Download Final Exam Review - Spring 2014

Katie Jurek’s BSC2010 Final Exam Review
This is not a comprehensive list, but simply a guide of what I’ve seen most often in the past.
Ch. 1 – Introduction
Cell Theory
1. Cells are made from other cells.
2. Cells make up all living things.
Q: What is DKPCOFGS?
-
Domain kingdom phylum class order family group species.
Ch. 2 – Atoms and Molecules
Valence electrons vs. valence

Valence electrons are how many electrons are already there in the outer orbital/valence
shell.

Valence is how many electrons are needed to get to 8.
Bonds

Covalent – “Share”.
o Polar covalent bonds – One element is more electronegative than the other.
o Nonpolar covalent bonds – Often symmetric.

Ionic – “Take”.

Hydrogen – More like magnetic attractions; atoms are not being shared.

Covalent > ionic > hydrogen bonds in strength, in general.
Isotopes: Atoms with the same number of protons but a different number of neutrons.
Q: According to the octet rule, the distribution of electrons in a sulfur atom (atomic #16)’s
orbitals is...?
-
2, 8, 6 (2 in first level, 8 in second, 6 in last).
Q: If the hydroxide concentration of a solution is 10-4, the hydrogen ion concentration is:
-
10-10 (Difference between 10-14 and 10-4 = 10-10).
Ch. 3 – Water
Hydrophilic – Water-loving, dissolves in water, polar.
Hydrophobic – Water-hating, doesn’t dissolve in water, nonpolar.
Solvent – Dissolves things; often water.
Solute – Gets dissolved by solvent; non-water.
Q: Does an acid have more or less H+ ions compared to a base?
-
More.
Q: Which portion of pH scale are acids and which are bases?
-
Below 7 is acidic, above 7 is basic, and exactly 7 is neutral.
Q: The cohesiveness of water molecules is due to what type of bond?
-
Hydrogen bonds. (The properties of water are due to hydrogen bonds)
Q: Name some properties of water.
-
Cohesion, adhesion, surface tension, high specific heat, expands upon freezing, universal
solvent.
Ch. 4 – Functional Groups, Isomers, and Carbon
Isomers: Structural isomers differ in shape (flat vs. branched), geometric isomers differ in
arrangement about a double bond, and enantiomers are mirror images of each other.
Functional groups: The functional groups are certain molecules attached to organic molecules:


hydroxyl – OH
carbonyl – CO
(alcohols)
(ketones, aldehydes)





carboxyl – COOH
amino – NH2
groups)
sulfhydryl – SH
phosphate – PO4
methyl – CH3
(acids; “carbonyl” + “hydroxyl” = “carboxyl”)
(amines; only one with N; amino acids have amino and carboxyl
(thiols; only one with S)
(ATP; only one with P)
(methylated compounds)
Q: What type of bonds does carbon form?
-
Covalent.
Q: Do isomers (geometric isomers, structural isomers, enantiomers) have equal biological
activity?
-
Nooooo~!
Ch. 5 – Macromolecules
Carbohydrates – Sugars aka polysaccharides. Also, glycogen (how animals store energy), starch
(how plants store energy), and cellulose (plant cell walls).
Lipids – Fats, phospholipids, and steroids.
Nucleic acids – DNA and RNA.
Proteins
Protein structure (and what bonds hold them together)
1. Primary (the sequence of amino acids)
2. Secondary (pleated sheet or coiled due to hydrogen bonds; causes hair proteins to
be either wavy or curly :D)
3. Tertiary (3-D shape due to R groups attracting; bedhead)

Most proteins stop at tertiary structure.
4. Quaternary (multiple tertiary structures; polypeptide bonds form a chain; a right
mess)

Examples of proteins that have quaternary structure: collagen (in the skin)
and hemoglobin (in the blood)
Denaturation – Proteins become denatured/lose their function due to (1) pH, (2) temperature,
(3) a change in salinity, or (4) chemical interference. Yes, several of these are essentially the
same thing; no, I don’t know why they’re considered separate categories. Bear with me, here. :D
Q: Which macromolecule must have C, H, and O in a 1:2:1 ratio?
-
Carbohydrates.
Ch. 6 – Cellular Organelles
Mitochondria – In eukaryotic cells, the mitochondrion produces massive amounts of ATP
through cellular respiration, thus its nickname “the powerhouse”.
ATP (and the PO4 functional group) – Adenosine triphosphate (ATP) contains a lot of energy in
its bonds because the three phosphates (PO4) are negatively charged and desperately want to
get away from each other.
Hypertonic, hypotonic, isotonic

Hypertonic means more solute than solvent/water. Keywords include “swell”, “burst”,
and “lyse”.

Hypotonic means more solvent/water than solute. Keywords include “shrink” and
“cremate”.

Isotonic means equal solvent/water and solute.
Ch. 7 – Membrane Structure and Function
Phospholipid bilayer: The phospholipid bilayer, which contains hydrophilic/polar heads and
hydrophobic/nonpolar tails, is the major component of the cell membrane.
Membrane transport

Passive transport
o Diffusion (high to low concentrations/with the concentration gradient)
o Facilitated diffusion (diffusion with the help of a protein)
o Osmosis (diffusion of water specifically)

Active transport
o From low to high concentrations/against the concentration gradient.
Junctions

Tight junctions (don't allow anything through)

Anchoring junctions (keep cells attached while they communicate)

Gap/communicating junctions (allow the transfer of proteins between cells)
Ch. 8 – Metabolism
Anabolic – Building up (think anabolic steroids)
Catabolic – Breaking down (think glycolysis breaks down glucose)
The Laws of Thermodynamics
1. Energy cannot be created nor destroyed, only transferred.
2. Every transfer of energy increases the entropy of the universe.
Gibbs free energy – Delta G is negative if energy is given off (spontaneous, exergonic), positive if
energy is consumed (nonspontaneous, endergonic). Think of delta G as the amount of energy
needed; if it is negative, none is needed.
Activation energy (Ea) – The initial amount of energy needed to start a chemical reaction.
Enzymes can lower this Ea barrier.
Catalyst – Speeds up a reaction without being consumed by the reaction.
Active site – Where the substrate is supposed to bind, but can be blocked by a competitive
inhibitor.
Q: How does a competitive inhibitor work?
-
By blocking the correct substrate from being able to fully attach to the enzyme/catalyst.
Ch. 9 – Cellular Respiration
Glycolysis: Lyses glucose; makes two pyruvates per glucose molecule.
Pre-citric acid cycle & citric acid cycle: At the end of glycolysis, the pyruvates:

If oxygen is present, go into the mitochondria and enter the Krebs/citric acid cycle, which
adds electrons onto the electron shuttles (reduces them). The ETC is activated.

If oxygen is not present, do not continue into the mitochondria. Cell respiration stops
and fermentation begins instead.
Electron transport chain: The electron shuttles combined with H+ ions go through the electron
transport chain and power chemiosmosis, creating a large amount of ATP.
Ch. 10 – Photosynthesis
Cellular respiration backward! Plants have the ability of carbon fixation (changing inorganic
carbon into organic carbon).
Ch. 12 – The Cell Cycle and Mitosis
Mitosis happens in the somatic (non-sex) cells. Starts diploid, produces 2 diploid clone cells.
[do cell cycle and mitosis on whiteboard]
Ch. 13 – Meiosis
Meiosis occurs in the sex cells/gametes (eggs and sperm). Starts diploid, produces 4 haploid
daughter cells.
[do meiosis on whiteboard]
Ch. 14 – Mendelian Genetics and Others
[do Punnett squares on whiteboard]
Epistasis – One gene affects the expression of another gene (black, brown, and yellow
labradors; a yellow lab has a second gene that inactivates its coat color gene).
Pleiotropy – One gene, multiple phenotypes (e.g. cystic fibrosis).
Polygenic inheritance – Multiple genes, one phenotype (e.g. hair color, eye color, skin color).
Complete dominance – The default; both AA and Aa would give the dominant phenotype (red x
white flower = red heterozygote).
Incomplete dominance – The heterozygote Aa gives a halfway in-between phenotype (red x
white flower = pink heterozygote).
Codominance – The heterozygote gets both phenotypes expressed fully (A blood x B blood = AB
blood).
Ch. 15 – Sex-Linked Traits
[do sex-linked Punnett squares on whiteboard]
Ch. 16 – DNA Replication/RNA Synthesis
DNA is synthesized during the S stage of the cell cycle. This chapter zooms in on that stage to
talk about what actually happens.
[do DNA replication on whiteboard]
Enzymes used in DNA replication

Helicase – Unwinds the DNA.

Single-stranded binding proteins – Stabilizes the unwound strands.

Topoisomerase – Prevents overwinding and twisting of not-yet-unwound strands.

Primase – Creates the primer, which lays down the first few nucleotides.

DNA polymerase – Continues laying down nucleotides, also proofreads the nucleotides
that have already been added.

Ligase – Ties back up the DNA strands and Okazaki fragments when they are done being
replicated.
Q: Where does DNA replication occur?

Wherever the DNA is (nucleus in eukaryotes, cytoplasm in prokaryotes).
Ch. 17 – Transcription and Translation
[do transcription and translation on whiteboard]
The Central Dogma of Biology – DNA  transcription  RNA  translation  proteins
Ch. 18 – The Regulation of Gene Expression
An operon contains the operator (the actual gene switch), promoter, and the genes it controls.
Operons can be repressible or inducible:

If they are repressible, they are on (you can’t repress something that hasn’t begun!).

If they are inducible, they are off (you can’t start something that’s already begun!).
Repressors, if active, can turn operons off by binding to their operators and blocking RNA
polymerase from touching (and thus translating) the genes.
Ch. 22 – Descent with Modification: Darwin and Others
Sexual Selection

Intersexual (“between different sexes”) = Females prefer certain mates.

Intrasexual (“among the same sex”) = e.g. Males compete with one another; one
becomes alpha and mates with the female.
Sexual dimorphism – The differences between males and females of the same species.
3 Key Points to Natural Selection

Individuals do not evolve, populations evolve.

Natural selection only works on heritable traits with variation in the population.

Evolution is not working towards a specific goal or “perfect” organisms.
Homologous structures – Structures that evolved from a common ancestor (e.g. human hands
and bat wings).
Vestigial structures – Structures that have lost their ancestral functions but are still present (e.g.
a whale’s pelvic bone).
Adaptation – Traits with useful roles are selected for in natural selection.
Jean Baptiste Lamarck – Hypothesized that acquired traits can be inherited (e.g. thought
giraffes progressively stretched their necks farther and farther and could pass down these
longer necks to their children)
Charles Darwin – Wrote On the Origin of Species; sailed to the Galapagos Islands and noticed
profound differences in the finches there, specifically their beaks. He proposed these finches all
came from a common ancestor but had evolved to eat their own type of food source on the
island.
Theory of Evolution

Change through time.

Descent with modification.

Genetic changes in population over time.

Unifying theory of biology.
-
Note: A scientific theory is much more heavily evidenced than the connotation of
“theory” used in everyday conversation! For example, gravity is also a theory.
Q: How does natural selection cause change in a population?
-
By selective advantage; certain individuals will have more suitable characteristics for
their environment and will tend to be able to reproduce more often.
Q: What does natural selection act on in the population?
-
Inherited characteristics that lead to an advantage in the environment.
Q: What fields have shown evidence to support natural selection as a mechanism of
evolution?
-
Biology, geology, chemistry, physics.
Ch. 23 – The Evolution of Populations
Null hypothesis vs alternative hypothesis

Null hypothesis: no difference (e.g. “White tigers have the same lifespan as orange
tigers”).
o “Null” means “zero” in other languages, so “zero difference”.

Alternative hypothesis: there is a difference (e.g. “White tigers live shorter than orange
tigers”).
Limits of natural selection

Selection can only act on existing variation in a population.

Evolution is limited by historical constraints.

Adaptations are usually compromises.

Natural selection interacts with chance/random events and the environment.
Microevolution
Many things can cause change in a population:

Mutations – A permanent change in the DNA sequence of a gene (e.g. having blue eyes).

Natural Selection – Selective advantage of those individuals better suited for the
environment.

Genetic Drift – Change in allele frequency due to random sampling.

Gene Flow – Moving genes from one population to another.
Hardy-Weinberg
p + q = 1 (allele frequencies)
p2 + 2pq + q2 = 1 (genotype frequencies)
p = dominant allele frequency
q = recessive allele frequency
p2 = homozygous dominant frequency
2pq = heterozygote frequency
q2 = homozygous recessive frequency
Hardy-Weinberg: 5 Assumptions
1. No natural selection.
2. No mutation.
3. No gene flow.
4. Completely random mating.
5. Large population.
-
The Hardy-Weinberg principle is a “null hypothesis” to check for evolution; it is
almost always violated by real populations.
Hardy-Weinberg Problems
A population of 100 butterflies has a dominant brown color and a recessive white color.
1. If the frequency of the brown allele is 0.8, what is the frequency of the white
allele?
p = 0.8
p+q=1
q = 1 – 0.8 = 0.2
2. Calculate the predicted frequencies of the genotypes if population is at HardyWeinberg equilibrium.
p= 0.8, q= 0.2; genotype frequency equation= p2 + 2pq + q2 = 1
p2 = (0.8)2 = 0.64
2pq= 2(0.8)(0.2) = 0.32
q2 = (0.2)2 = 0.04
0.64 + 0.32 + 0.04 = 1
3. In the butterfly population, 25% are dominant homozygous, 50% are heterozygous,
and 25% are homozygous recessive. Find p and q for this population.
Frequency of homozygous dominant = p2 = 0.25, p = √0.25 = 0.5
Frequency of homozygous recessive = q2 = 0.25, q = √0.25 = 0.5
Frequency of heterozygous = 2pq = 0.5
Ch. 24 – The Origin of Species
Speciation – The formation of new, distinct species.
Allopatric speciation – “Different country”, aka two species developing in separated areas.
Sympatric speciation – “Same country”, aka two species developing in the same area.
Reproductive barrier – Anything that inhibits reproduction.

Pre-zygotic barriers

Post-zygotic barriers
Macroevolution – Evolution of taxonomic groups over long periods.
Q: What are some different types of post-zygotic barriers?
-
Reduced hybrid viability or fertility, or hybrid breakdown.