BIO 240 FINAL EXAM

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kinetochore microtubule

A __________ is a complex of proteins attached to a centromere that mediates the attachment and movement of chromosomes along the mitotic spindle.

pyruvate oxidation

Acetyl CoA is produced by what step of cellular respiration?

Golgi apparatus

After leaving the ER, many transport vesicles travel to the _________

isotopes

All atoms of a given element have the same number of protons (same atomic number), but some atoms have more neutrons than other atoms of the same element and therefore have greater mass (different mass numbers); these different atomic forms of the same element are called __________ of the element.

element

An atom is the smallest unit with the properties of a(n) _________

INCREASES

An enhancer is a DNA sequence that ___________ transcription of a gene independently of its position, orientation, and distance from a promoter.

complementary

An mRNA molecule is __________ to its DNA template.

30 or 32 ATP

Approximately how many ATP are produced per molecule of glucose?

∼32

Approximately how many ATP's are made per molecule of glucose?

26 or 28 ATP

Approximately how many ATP's are produced from oxidative phosphorylation?

transcription

Bacteria often respond to environmental change by regulating ___________

Because tryptophan is a COREPRESSOR, it must be PRESENT in order for the repressor protein to be ACTIVE

Because tryptophan is a COREPRESSOR, it must be _________ in order for the repressor protein to be ACTIVE

S phase

Before mitosis or meiosis can occur, DNA is replicated during the __ phase of interphase

Chemical behavior of an atom depends on: • valence shell (b/c an atom wants to fill its outer shell with the max # of VE's) • VE's

Control elements are segments of noncoding DNA that serve as BINDING SITES for proteins called SPECIFIC TRANSCRIPTION FACTORS

Control elements are segments of noncoding DNA that serve as ____________ for proteins called _______________

Coordinately controlled genes in eukaryotic cells are activated by the same CHEMICAL SIGNALS

Coordinately controlled genes in eukaryotic cells are activated by the same ____________

DNA polymerase can ONLY add a nucleotide to the ___ end of an existing nucleotide chain

descent with modification

Darwin argued that all the organisms that have ever lived arose through ____________

all alleles for all loci in a population

Define a gene pool

✰ POPULATION ✰ • SMALLEST evolving biological unit • group of the same species that live in the same area and interbreed, producing fertile offspring

Define a population (2)

the abundance of one allele relative to others at the same gene locus in individuals of a population

Define allele frequency

an allele that is the only variant that exists for that gene in ALL the population, and all individuals are HOMOZYGOUS for that allele

Define fixed allele

the process by which one species splits into two or more species

Define speciation

the science of the classification of organisms based on similarities in features

Define taxonomy

21 (hence Down syndrome's other name: trisomy 21)

Down syndrome arises from nondisjunction of chromosome ___ during the meiotic divisions

as electrons move from PSII to the cytochrome complex

During the light reactions, when are H⁺ ions pumped into the thylakoid space?

prophase I

During what phase of meiosis does crossing over occur?

protons (and electrons)

Each element has an atomic number that is defined by the number of _________

distal control elements

Each enhancer is made of short DNA sequences called ______________.

shells

Electrons are located in _____ ↺ the nucleus

lac repressor → NEGATIVE CONTROL CAP → POSITIVE CONTROL

Explain how the lac operon involves both the POSITIVE and the NEGATIVE control of genes.

The state of the lac repressor (with allolactose bound or without it) determines whether or not transcription of the lac operon's genes OCCURS AT ALL; the state of CAP (with cAMP bound or without it) controls the RATE of transcription if the operon is repressor-free lac repressor → will transcription occur? CAP → how fast will transcription occur?

Explain the difference between the functions of the lac repressor and CAP

Both operons are switched OFF by the active form of their respective repressor protein

Explain why the regulation of both the trp operon and the lactose operon involve the NEGATIVE control of genes.

• 🌿 cells prefer a HYPOTONIC (solute < solution) environment b/c they want MORE H₂O entering the cell than leaving the cell • the increased H₂O uptake allows the plasma membrane to exert pressure on the cell wall, thus allowing the 🌿 to stay upright

Explain why this statement is false: 🌿 cells prefer a hypertonic environment

hormonal proteins

F: coordination of an organism's activities Ex: insulin

contractile and motor proteins

F: movement Ex: motor proteins

defensive proteins

F: protection against disease Ex: antibodies

receptor proteins

F: response of cell to chemical stimuli Ex: nerve cell receptors

enzymatic proteins

F: selective acceleration of chemical reactions Ex: digestive enzymes

storage proteins

F: storage of amino acids (protein monomers) Ex: ovalbumin is used as an amino acid source for the developing embryo

structural proteins

F: support Ex: keratin, collagen, elastin

transport proteins

F: transport of substances Ex: hemoglobin, protein channels

ONE (it's called the template strand)

For each gene, how many of the 2 DNA strands are transcribed?

mutations that affect the gametes

For most organisms, which mutations are heritable?

5'-GUUUAACCGAAUAAUGGCCUAC-3'

For the DNA template shown, what would be the sequence of an RNA transcribed from it?

proteins

Genes provide the instructions for making specific _______

polydactyly, Huntington's disease

Give an example of a dominantly inherited disorder

albinoism, sickle cell anemia, cystic fibrosis

Give an example of a recessively inherited disorder

HCl → H⁺ + Cl⁻ (high [H⁺])

Give an example of a strong acid dissociating in water (be able to write out the reaction). Are the products low or high in [H⁺]?

NaOH → Na⁺ + OH⁻ (low [H⁺])

Give an example of a strong base dissociating in water (be able to write out the reaction). Are the products low or high in [H⁺]?

H₂CO₃ (carbonic acid) ⇌ HCO₃⁻ + H⁺

Give an example of a weak acid dissociating in water (be able to write out the reaction).

NH₃ (ammonia) + H⁺ ⇌ NH₄⁺

Give an example of a weak base dissociating in water (be able to write out the reaction).

1. Adhesion of water to cell walls by hydrogen bonds helps resist downward pull of gravity 2. As water evaporates from the leaves, the escaping water pulls more water upward from the roots (cohesion)

Give an example of adhesion/cohesion.

photosynthesis

Give an example of an endergonic reaction.

cellular respiration

Give an example of an exergonic reaction.

bacteria

Give an example of an organism that goes through asexual reproduction

blood types

Give an example of codominance.

• the sugar glider and the flying squirrel; BOTH animals are in a similar environment and need a way to travel from tree to tree, so they evolve SIMILAR structures that allow for flight (BUT THEY HAVE DIFFERENT BONE STRUCTURES)

Give an example of convergent evolution.

snapdragon flowers

Give an example of incomplete dominance.

In an overfilled glass of water, water doesn't spill over due to hydrogen bonds bonding the water at the top to all the water below it

Give an example of surface tension.

p (dom) = (# of copies of allele CR) ÷ (total # of CR/CW alleles in population) p (dom) = 800 ÷ (800+200) = .8 (80%)

Given that there are 200 CW recessive allele copies and 800 CR dominant allele copies, what is the frequency of dominant alleles?

q (rec) = (# of copies of allele CW) ÷ (total # of CR/CW alleles in population) q (rec) = 200 ÷ (800+200) = .2 (20%)

Given that there are 200 CW recessive allele copies and 800 CR dominant allele copies, what is the frequency of recessive alleles?

# of CR allele copies = 2*(CRCR) + 1*(CRCW) = 2*(320) + 1*(160) = 800 CR allele copies

Given that there are 320 red flowers (CRCR), 160 pink flowers (CRCW), and 20 white flowers (CWCW), what is the number of CR allele copies?

# of CW allele copies = 2*(CWCW) + 1*(CRCW) = 2*(20) + 1*(160) = 200 CW allele copies

Given that there are 320 red flowers (CRCR), 160 pink flowers (CRCW), and 20 white flowers (CWCW), what is the number of CW allele copies?

Hardy-Weinberg equilibrium is the state of a population in which ALLELE FREQUENCIES and GENOTYPE FREQUENCIES remain CONSTANT from generation to generation

Hardy-Weinberg equilibrium is the state of a population in which ____________ and _________- remain CONSTANT from generation to generation

miRNA's

How can introns block translation?

C. reduce the number of double bonds between carbon atoms to allow more room for hydrogen atoms Explanation: a fat is "saturated" when it has NO double bonds in its structure, thus allowing more room for hydrogens (such a fat is "saturated" with as many hydrogens as the carbon skeleton will allow)

How could one "saturate" an unsaturated fat? A. increase the number of double bonds between carbon atoms to prohibit more hydrogen atoms from bonding to the structure B. reduce the number of hydrogen atoms to allow more room for carbon atoms C. reduce the number of double bonds between carbon atoms to allow more room for hydrogen atoms

"descent with modification" (the idea that species sharing a common ancestor change over time and give rise to new species)

How did Darwin define evolution?

✰ USE AND DISUSE OF BODY PARTS ("USE IT OR LOSE IT") ✰ • the idea that parts of the body that are used extensively become LARGER and STRONGER, while those that are not DETERIORATE ("use it or lose it" theory) ✰ INHERITANCE OF ACQUIRED CHARACTERISTICS ✰ • the idea that an organism could pass modifications to its offspring

How did Lamarck explain evolution (2)?

by oxidizing organic fuels

How do catabolic pathways yield energy?

by REDUCING the E(a)

How do enzymes speed up reactions?

hydrogen bonds allow water to stick together → A LOT of energy is required to first break these stubborn hydrogen bonds and THEN allow water molecules to move faster (get hotter) → therefore, water's specific heat is UNUSUALLY HIGH

How do hydrogen bonds affect water's specific heat?

rewrite the sequence of the coding strand in the 5'→3' direction while replacing the T's with U's

How do you determine the mRNA sequence from the coding strand sequence?

by coupling exergonic reactions with endergonic reactions

How does ATP power cellular work?

RNA polymerase is RECRUITED by GENERAL TRANSCRIPTION FACTORS

How does RNA polymerase find the promoter in a eukaryote?

acetylation (acetyl groups + histone tails) → LOOSER chromatin structure → INCREASED access to DNA → INCREASED transcription

How does acetylation affect the rate of transcription?

• (@ warm temperatures): cholesterol restrains movement of phospholipids • (@ cool temperatures): cholesterol prevents tight packing

How does cholesterol affect membrane fluidity at different temperatures?

Water is a polar molecule, with a slight negatively charged end and a slightly positively charged end. This polarity means that it attracts other water molecules, and this attraction between water molecules is hydrogen bonding

How does hydrogen bonding affect water polarity?

methylation (methyl groups + histone tails) → TIGHTER chromatin structure → DECREASED access to DNA → DECREASED transcription

How does methylation affect the rate of transcription?

• global warming → ↑↑ CO₂ in atmosphere → ↑↑ photosynthesis → ↓↓ photorespiration

How has global warming positively affected crop yields?

How many elements occur in nature?

22 pairs

How many of humans' chromosome pairs are autosomes?

1 pair

How many of humans' chromosome pairs are sex chromosomes?

23 pairs

How many pairs of chromosomes do humans have?

two (inner and outer)

How many phospholipid bilayer membranes does the nuclear membrane have?

Hybrid breakdown is a barrier to speciation because some first-generation hybrids are viable and fertile, but when they mate with one another or with either parent species, offspring of the next generation are FEEBLE or STERILE

Hybrid variability is a barrier to speciation because the genes of different parent species may interact in ways that IMPAIR the hybrid's development or survival in its environment

Hybrid variability is a barrier to speciation because the genes of different parent species may interact in ways that _______ the hybrid's development or survival in its environment

If [H⁺] = 10⁻⁶, then pH = 6

If [H⁺] = 10⁻⁶, then pH = ?

If [H⁺] = 10⁻⁸, then pH = 8

If [H⁺] = 10⁻⁸, then pH = ?

dominant

If a dihybrid parent is true breeding dominant, both of its genes will have _________ alleles.

the cytosol has a near neutral pH

If a lysosome were to break open, what keeps a cell safe from the dangerous acidity of its contents?

in the rough ER

If a protein is going to be sent OUTSIDE of the cell , where is the ribosome that synthesizes it likely going to be located?

in the cytosol

If a protein is going to be sent to the CYTOPLASM, where is the ribosome that synthesizes it likely going to be located?

GENE EXPRESSION (some proteins are made in EVERY cell, some proteins are only made in SPECIFIC cells b/c they have SPECIFIC FUNCTIONS)

If the DNA in your brain cells, liver cells, and eye cells is the SAME, then why do the cells have different functions?

2 ATPs Net ∆G = 9.2 + 2(-7.3) = -5.4 kcal/mol; if only 1 ATP were used, the net ∆G would be +1.9 kcal/mol, making the overall reaction NON-SPONTANEOUS and unable to occur

If ∆G(Glu) were 9.2 kcal/mol, how many ATP's [∆G(ATP)=-7.3 kcal/mol] would be required for the formation of glutamic acid to proceed?

equal

In a nonpolar covalent bond, there is ______ pulling

unequal

In a polar covalent bond, there is ______ pulling

10⁻¹⁴

In any aqueous solution, the product of the H⁺ and OH⁻ concentration is constant at ___

6CO₂

In cellular respiration, what does glucose become after being oxidized?

6H₂O

In cellular respiration, what does oxygen become after being reduced?

In eukaryotes, the rate of gene expression can be strongly increased or decreased by the binding of SPECIFIC TRANSCRIPTION FACTORS, (either activators or repressors), to the CONTROL ELEMENTS of enhancers

In eukaryotes, the rate of gene expression can be strongly increased or decreased by the binding of _______________, (either activators or repressors), to the ______________ of enhancers

sperm

In mammals, the sex of an offspring depends on whether the ______ cell carries an X or a Y

In mitosis, 1 parent divides to produce __ identical offspring.

ABSENT

In order for the trp operon to be ON, tryptophan must be ________

C₆H₁₂O₆ (glucose)

In photosynthesis, what does 6CO₂ become after being reduced?

6O₂

In photosynthesis, what does 6H₂O become after being oxidized?

• 4 = mass number • 2 = # of protons • 2 neutrons

In the abbreviation ⁴₂He, what do the 4 and the 2 indicate? How many neutrons does this atom have?

to conserve energy [it would be ENERGETICALLY WASTEFUL for E. coli to express the lac genes (whose purpose is to encode inducible enzymes that metabolize lactose) when there's no lactose present]

In the absence of lactose within an E. coli cell, why does the lac repressor bind to the operator and keep RNA polymerase from transcribing the lac genes?

DNA is turned into RNA; ribosomes

In the nucleus, ____ is turned into _____; then, it is sent out of the nuclear pores so it can find _______

inhibit

In the pathway for tryptophan synthesis, an ABUNDANCE of tryptophan can _______ the expression of certain genes that make the enzymes in the pathway

5'→3' direction

In what direction is mRNA read?

if there are LOW LEVELS OF LACTOSE, transcription of the lac operon will NOT occur because the lac repressor will bind to the operator and block RNA polymerase

In what situation will transcription of the lac operon absolutely NOT occur, regardless of the glucose level? Why?

catabolic

Is cellular respiration catabolic or anabolic?

catabolic • cellular respiration BREAKS DOWN glucose

Is cellular respiration catabolic or anabolic?

exergonic • cellular respiration is a SPONTANEOUS process (it DOESN'T require energy input)

Is cellular respiration exergonic or endergonic?

passive transport

Is diffusion passive or active transport?

catabolic (b/c you're breaking down the food in order to RELEASE NUTRIENTS)

Is eating a catabolic or anabolic reaction?

anabolic (+∆G) • anabolic processes BUILD UP complex products with HIGHER ENERGY than their reactants • photosynthesis REQUIRES light energy to be put IN... it is NOT spontaneous (hence a +∆G)

Is photosynthesis catabolic or anabolic?

protons and neutrons

Mass number is the total number of ______ and ______ in the nucleus of the atom

elements

Matter is made of _______

4; half

Meiosis I and meiosis II result in __ daughter cells, each with ____ as many chromosomes as the parent cell

diploid → haploid

Meiosis is a division process that takes us from a _______ cell to _______ cells.

asexual

Mitosis is a form of ________ reproduction

starch (🌿), glycogen (🐖), cellulose (🌿)

Name 3 polysaccharides of glucose

Transport Enzymatic activity Attachment to the cytoskeleton & ECM Cell-cell recognition Intercellular joining Signal transduction

Name 6 functions of membrane proteins (TEACIS)

🔑 plasma membrane (aka cell membrane, or phospholipid bilayer) 🔑 cytoplasm (the part of the cell which is contained within the entire cell membrane; full of water) 🔑 chromosomes (DNA) 🔑 ribosomes (F: synthesize proteins)

Name the basic features present in ALL cells (Penguins Clubbed Capricious Raspberries)

Nondisjunction during meiosis I produces TWO (n+1) gametes with an extra chromosome and TWO (n-1) gametes with a missing chromosome

Nondisjunction during MEIOSIS I produces __ gamete(s) with an extra chromosome (n+1) and __ gamete(s) with a missing chromosome (n-1)

Nondisjunction during meiosis II produces TWO (n) gametes with a normal number of chromosomes, ONE (n+1) gamete with an extra chromosome, and ONE (n-1) gamete with a missing chromosome

Nondisjunction during MEIOSIS II produces __ gamete(s) with a normal number of chromosomes (n), __ gamete(s) with an extra chromosome (n+1), and __ gamete(s) with a missing chromosome (n-1)

NUCLEAR LAMINA (series of fibers maintaining the nucleus' shape)

Nuclear pores are located on the OUTSIDE of the nuclear envelope; if you are on the INSIDE the nucleus looking OUT at the envelope, what do you see?

Carbon Hydrogen Oxygen Nitrogen Phosphorus Sulfur

Of the 92 elements in nature, six of them are ESSENTIAL ELEMENTS that make up 96% of all living bodies. Name them. (hint: CHONPS)

On a cellular level, why can cutting off someone's air supply eventually kill them?

• UNSATURATED TAILS: fluid, prevent packing (recall that unsaturated fatty acids are LIQUID @ room temp) • SATURATED TAILS: viscous, tightly packed (recall that saturated fatty acids are SOLID @ room temp)

Phospholipids can have unsaturated tails or saturated tails. Describe their differences in terms of fluidity & packing.

if you try to flip the phospholipid, you'd be forcing the hydrophilic portion (the head) to go through the hydrophobic interior

Phospholipids typically move laterally (↔) within the plasma membrane. Why is it difficult for phospholipids to flip across the plasma membrane?

endoplasmic reticulum

Polypeptide synthesis ALWAYS begins in the cytosol in a FREE RIBOSOME and will proceed to completion UNLESS the growing polypeptide cues the ribosome to attach to the _______________

free ribosomes

Polypeptides destined for the cytosol are synthesized on ____________ in the cytosol

bound ribosomes

Polypeptides destined for the endomembrane system or for secretion are synthesized on __________ in the endoplasmic reticulum

1. RNA processing 2. mRNA degradation 3. Translation 4. Protein processing and degradation

Post transcriptional regulation includes what 4 stages in eukaryotes?

success

Postzygotic isolating mechanisms reduce the ________ of hybrid offspring

production

Prezygotic isolating mechanisms prevent the _________ of hybrid offspring

acetyl CoA

Pyruvates do NOT go into the citric acid cycle; only ______ goes into the citric acid cycle

TRANSCRIPTION FACTORS

Regulation of transcription initiation involves the effects of ______________ binding to a gene's promoter and regulatory sites

the liver

Smooth ER are important in the cells of which organ?

The GREATER the distance between two genes on a chromosome, the GREATER the chance that a crossover can form between the genes, and the GREATER the recombination frequency.

The GREATER the distance between two genes on a chromosome, the _______ the chance that a crossover can form between the genes, and the _______ the recombination frequency.

5'-UGGUUUGGCUCA-3' OR 3'-ACUCGGUUUGGU-5'

The coding strand of a given gene gives the sequence 5'-TGGTTTGGCTCA-3'. What is the sequence of the mRNA strand?

whether the ribosome that synthesizes it is in the rough ER or in the cytosol

The destination of a protein depends on what?

poly-A tail

The finite lifespan of an mRNA molecule in the cytoplasm depends on the length of the ____________ at the 3' end

electrons

The more electronegative an atom is, the more strongly it pulls shared _______ towards itself

nucleus; ribosome assembly

The nucleolus is located inside the _______ of eukaryotic cells; its function is _______

to synthesize proteins

The nucleolus' job is to synthesize ribosomes. What is the ribosome's job?

nuclear envelope

The nucleus is surrounded by the __________

electronegativity

The sharing of electrons in a covalent bond is not always equal between atoms; the attraction of a particular atom for the electrons of a covalent bond is called its __________

The significance of isotopes: • carbon dating (radioactive carbon-14 isotope can be used to determine age of organic substance) • atomic bomb (require isotopes b/c bombs use radioactive uranium-235) • Iran & uranium enrichment (use of machinery to enrich uranium-235)

parent

The two chromosomes of a homologous pair are individual chromosomes that were inherited from each ______

the promoter

To which part of the DNA does RNA polymerase bind to begin transcription?

the operator

To which part of the DNA does a regulatory protein bind in order to affect the expression of the protein?

TRUE

True or False: ATP hydrolysis is an exergonic process

TRUE

True or False: EVERY living organism evolves

FALSE: H₂ has a NONPOLAR covalent bond • in a covalent bond between 2 atoms of the SAME ELEMENT, the electrons are shared EQUALLY b/c the 2 atoms have the SAME ELECTRONEGATIVITY

True or False: H₂ has a polar covalent bond

True

True or False: H₂O is a compound

False: The molecules H₂ and O₂ are PURE ELEMENTS • a COMPOUND is a combination of 2 or more DIFFERENT elements

True or False: The molecules H₂ and O₂ are compounds

FALSE • X-linked recessive disorders are more common in MALES because they only have 1 X chromosome while females have two X chromosomes

True or False: X-linked recessive disorders are more common in females

FALSE • "SPONTANEOUS" implies that the reaction does not require energy input and thus is ENERGETICALLY FAVORABLE

True or False: a "spontaneous" reaction occurs rapidly

TRUE

True or False: all of your somatic cells are diploid cells

FALSE: an acid is a proton DONOR

True or False: an acid is a proton acceptor

FALSE: an acid is any substance that INCREASES the hydrogen ion concentration of a solution • a BASE is any substance that decreases the hydrogen ion concentration of a solution

True or False: an acid is any substance that decreases the hydrogen ion concentration of a solution

FALSE

True or False: an element can be broken down into simpler substances

FALSE

True or False: at the end of the citric acid cycle, much of the ATP has already been produced

FALSE • eukaryotic cells have MANY MORE origins of replication than a bacterial cell

True or False: bacterial cells have more origins of replication than do eukaryotic cells

FALSE • control elements are located "UPSTREAM" (BEFORE) from the promoter

True or False: control elements (both proximal and distal) are located "downstream" from the promoter

FALSE • crossing over, the pairing of homologous chromosomes at the metaphase plate, and the separation of homologous chromosomes ALL OCCUR during meiosis I

True or False: crossing over, the pairing of homologous chromosomes at the metaphase plate, and the separation of homologous chromosomes ALL OCCUR during meiosis II

FALSE • distal control elements (enhancers) are VERY FAR AWAY (1000's of base pairs away!!!) from the promoter

True or False: distal control elements (enhancers) are located very close to the promoter

FALSE • due to CROSSING OVER of sister chromatids during PROPHASE I, the two sister chromatids of each chromosome are 🚫 genetically identical

True or False: during metaphase II, the sister chromatids are genetically identical

FALSE • enzymes REDUCE the E(a) in order to speed up a reaction

True or False: enzymes increase the activation energy in order to speed up a reaction

FALSE • PROKARYOTES: binary fission • EUKARYOTES: mitosis

True or False: eukaryotes go through binary fission

FALSE • gametes are HAPLOID cells

True or False: gametes are diploid cells

FALSE • gene flow can increase OR decrease the fitness of a population • gene flow can lead to the gain OR loss of alleles

True or False: gene flow always increases the fitness of a population

FALSE • NATURAL SELECTION is the only mechanism that consistently causes adaptive evolution

True or False: genetic drift is the only mechanism that consistently causes adaptive evolution

FALSE • factors that CAUSE evolution must be at work

True or False: genetic variation guarantees evolution

FALSE • glycolysis can start with cholesterol, proteins, glycerol, etc.

True or False: glycolysis ALWAYS starts with glucose

FALSE • human sex determination depends on the Y chromosome because the Y chromosome contains the SRY (Sex determining Region of Y) gene, which is required for the development of testes - in the ABSENCE of SRY, gonads turn into OVARIES - in XX embryos, which do NOT have a copy of the SRY gene, development proceeds toward female reproductive structures

True or False: human sex determination depends on the X chromosome

FALSE • the F₁ offspring were MONOHYBRIDS (heterozygous)

True or False: in Mendel's pea experiments, the F₁ offspring were dihybrids

TRUE

True or False: in eukaryotes, there are more options for gene regulation than in prokaryotes

FALSE • POPULATIONS evolve, NOT individuals

True or False: individuals evolve

FALSE - living organisms will NEVER be in dynamic equilibrium

True or False: living organisms can sometimes be in dynamic equilibrium

True

True or False: methane is a nonpolar molecule

FALSE • TETRADS are ONLY involved in meiosis!!

True or False: mitosis has tetrads

True

True or False: only eukaryotic cells have chromatin

TRUE

True or False: organisms can evolve at SOME loci while being in Hardy-Weinberg equilibrium at other loci

FALSE • only EUKARYOTES have telomeres • most prokaryotes have a CIRCULAR chromosome with 🚫 ENDS, so shortening of DNA does 🚫 occur

True or False: prokaryotes (bacteria) have telomeres

FALSE - a eukaryotes have 80S ribosomes, prokaryotes have 70S ribosomes (80S > 70S)

True or False: prokaryotes have larger ribosomes than eukaryotes

FALSE • rRNA and tRNA do 🚫 encode proteins

True or False: rRNA and tRNA are included in the 2% of DNA that encodes proteins

FALSE • a SILENT mutation is a mutation in which a sense codon is changed to a different sense codon, but the new codon specifies the SAME amino acid, thus leaving the function of the polypeptide UNCHANGED *SILENT → UNCHANGED

True or False: silent mutations significantly alter the function of an affected polypeptide

FALSE • NOT ALL physical features that look alike reflect common ancestry ↓ • in convergent evolution, organisms NOT CLOSELY RELATED that live in similar environments can independently evolve SIMILAR FEATURES (ANALOGOUS FEATURES)

True or False: similarities in physical features of two organisms reflects a common ancestry

FALSE • because males only have 1 X chromosome, they will ALWAYS express an X-linked gene

True or False: sometimes, a man can be a carrier for an X-linked gene

FALSE: • the anticodon and the 3' end binding the amino acid are located at the OPPOSITE tips of the tRNA structure

True or False: the anticodon and the 3' end binding the amino acid are located at the SAME tip of the tRNA structure

FALSE • the FARTHER apart 2 genes are on a chromosome, the HIGHER the probability that a crossover will occur

True or False: the closer two genes are on a chromosome, the higher the probability that a crossover will occur

FALSE • the effects of genetic drift are more dramatic in small populations than in large populations

True or False: the effects of genetic drift are more dramatic in extremely large populations than in small populations

TRUE (b/c the lac operon is normally OFF)

True or False: the lac operon is an inducible operon

FALSE • the lac repressor protein is active BY ITSELF, binding to the operator and switching the lac operon OFF - in this case, an INDUCER (allolactose) can bind to the lac repressor protein and INACTIVATE it to switch the lac operon ON

True or False: the lac repressor protein requires a corepressor to be active and bind to the operator

FALSE • the LESS free energy there is in a system, the MORE STABLE and MORE FAVORABLE the system is (because the system will be UNLIKELY TO CHANGE)

True or False: the more free energy there is in a system, the more stable the system is

FALSE: • the transfer of an electron ALLOWS a bond to form b/c it results in 2 ions of opposite charge • the actual ionic bond is the ATTRACTION between the oppositely charged ions

True or False: the transfer of an electron is the formation of an ionic bond

FALSE • the trp operon is a REPRESSIBLE OPERON (therefore, it is normally ON)

True or False: the trp operon is an inducible operon

FALSE • the GREATER the distance between two genes on a chromosome, the GREATER the chance that a crossover can form between the genes, and the GREATER the recombination frequency • therefore, two genes with a recombination frequency of 50% would be FARTHER apart on a chromosome compared to two genes with a recombination frequency of 2%

True or False: two genes with a recombination frequency of 50% are closer together on a chromosome compared to two genes with a recombination frequency of 2%

FALSE

True or False: when two species become geographically separated, they become independent species

molecule

Two molecules or atoms held together by a covalent bond constitute a ________

2; meiosis I; meiosis II

Unlike mitosis, meiosis takes place in __ consecutive cell divisions, called ________ and ________

the 2 sugar-phosphate backbones runs in opposite 5' and 3' directions

We describe DNA as "antiparallel." Why?

1. crossing over → PROPHASE I 2. homologous chromosomes (tetrads) pair at metaphase plate → METAPHASE I 3. separation of homologous chromosomes → ANAPHASE I

What 3 events are unique to meiosis (in comparison with mitosis)?

1. natural selection 2. genetic drift (founder effect, bottleneck effect) 3. gene flow

What 3 mechanisms directly alter allele frequencies and cause most evolutionary change?

polar, large molecules (i.e., sugars)

What CAN'T cross the lipid bilayer easily? Give an example.

phospholipids

What are ALL cell membranes made of?

chromatin (complex of DNA wrapped around HISTONE proteins )

What are chromosomes made of?

tightly coiled, already replicated DNA

What are chromosomes made of?

competitive and noncompetitive (allosteric)

What are the 2 kinds of inhibition?

endocytosis and exocytosis

What are the 2 methods of bulk transport?

energy conservation and multicellularity

What are the 2 reasons why cells shouldn't express every gene?

1. complementary bases must bind 2. nucleotide must be added to the 3' OH end of the chain

What are the 2 requirements for a free DNA nucleotide to be added onto a DNA strand?

light reactions and the Calvin cycle

What are the 2 stages of photosynthesis?

fats, phospholipids, steroids

What are the 3 kinds of lipids?

promoter, operator, functional genes

What are the 3 parts of an operon?

1. Reduced hybrid variability 2. Reduced hybrid fertility 3. Hybrid breakdown (primarily in 🌿)

What are the 3 postzygotic barriers to speciation?

1. mutations 2. natural selection/evolution 3. allele recombination (crossing over, independent assortment, random fertilization )

What are the 3 sources of genetic variation?

UAA, UAG, UGA

What are the 3 stop codons?

🔑 outer membrane 🔑 nucleoid 🔑 NO nucleus

What are the 3 🔑 characteristics of prokaryotes?

1. POPULATIONS evolve, 🚫 individuals 2. Natural selection acts only on HERITABLE TRAITS [somatic mutations (i.e., cancer) have 🚫 effect] 3. Natural selection DOES 🚫 CREATE NEW TRAITS (it acts on RANDOM MUTATIONS) 4. Evolution IS 🚫 GOAL-ORIENTED

What are the 4 key points about natural selection?

1. 🚫 mutations 2. random mating 3. 🚫 natural selection 4. extremely large population size 5. 🚫 gene flow (🚫 introduction of new genes into population)

What are the 5 conditions for Hardy-Weinberg equilibrium?

1. Temporal isolation 2. Habitat isolation 3. Behavioral isolation (especially seen in humans) 4. Mechanical isolation (i.e., snails' genitals don't line up) 5. Gamete isolation (primarily in ocean)

What are the 5 prezygotic barriers to speciation?

What are the differences between binary fission and mitosis?

• transcription is the production of ONE strand of mRNA from a template DNA strand • during transcription, a SPECIFIC GENE is transcribed • DNA replication is the production of TWO daughter strands of DNA • during DNA replication, the ENTIRE GENOME is copied

What are the differences between transcription and DNA replication?

YyRr x YyRr ⇩ YR Yr yR yr

What are the gamete possibilities if you self-pollinate a YyRr F₁ dihybrid?

lipids (usually phospholipids) and proteins

What are the staple ingredients of membranes?

1) all eukaryotes are enveloped by a DOUBLE MEMBRANE 2) ribosomes in mitochondria & chloroplasts are 70S RIBOSOMES (PROKARYOTIC); in addition, mitochondria & chloroplasts contain DNA separate from DNA found in the nucleus 3) mitochondria & chloroplasts REPLICATE INDEPENDENTLY of the cell

What are the three major points in endosymbiont theory?

interphase (90%), and M phase (10%)

What are the two major phases of the cell cycle in eukaryotes?

1) genes have specific locations (LOCI) on chromosomes 2) these chromosomes undergo the Law of Independent Assortment and the Law of Segregation during meiosis

What are the two major points of the Theory of Chromosomal Inheritance?

1. Adhesion/Cohesion 2. Moderation of Temperature 3. Expansion Upon Freezing 4. Versatile Solvent

What are water's 4 properties (caused by hydrogen bonds)?

phosphodiester bonds

What bond connects the sugars in a sugar-phosphate backbone in DNA and RNA?

phosphodiester bonds

What bonds hold together the sugar-phosphate backbone in RNA and DNA?

glycosidic bonds

What bonds monosaccharides together?

nonpolar, small molecules (i.e., hydrocarbons, CO₂, O₂, lipids)

What can cross the lipid bilayer easily? Give an example.

1. natural selection 2. genetic drift (founder effect, bottleneck effect) 3. gene flow

What causes a population to move out of Hardy-Weinberg equilibrium (what causes the allele frequencies to shift) ?

1. natural selection 2. genetic drift (founder effect, bottleneck effect) 3. gene flow

What causes a shift out of H-W equilibrium (3)?

phosphodiester bond

What connects the sugars in DNA/RNA's sugar-phosphate backbone?

chemical behavior

What do electrons determine?

∆G

What do enzymes NEVER EVER EVER affect?

control elements

What do specific transcription factors bind to?

inorganic phosphate, ADP, and energy (released)

What does ATP hydrolysis yield?

Protons : element Electrons : chemical behavior Neutrons : isotope

What does each subatomic particle determine?

p² + 2pq + q² = 1 p² → expected frequency of homozygous dominant genotype 2pq → expected frequency of heterozygous genotype q² → expected frequency of homozygous recessive genotype

What does the Hardy-Weinberg equation state?

A helium atom has 2 protons in its nucleus

What does the abbreviation ₂He tell you?

the noble gases

What elements have a full valence shell?

descent from a common ancestor (DIVERGENT EVOLUTION)

What explains anatomical similarities in vertebrate embryos?

FADH₂, b/c it is the reduced form of FAD⁺

What has more energy, FAD⁺ or FADH₂?

hydrogen bonds

What holds together the bases in a double helix structure?

evolutionary theory of the origin of eukaryotic cells from prokaryotic cells

What is "endosymbiont theory"?

the state of a population in which frequencies of alleles and genotypes remain CONSTANT from generation to generation (that is, the population is NOT EVOLVING)

What is Hardy-Weinberg equilibrium?

a hybrid that is heterozygous for TWO different traits

What is a dihybrid?

a lipid with an attached carbohydrate

What is a glycolipid?

a protein with an attached carbohydrate

What is a glycoprotein?

a hybrid that is heterozygous for ONE trait

What is a monohybrid?

an anion

What is a negatively charged atom?

a protein loosely bound to surface of membrane; only on 1 side or the other of the membrane

What is a peripheral protein?

a semi-permeable phospholipid bilayer

What is a plasma membrane?

a cation

What is a positively charged atom?

an offspring resulting from a crossing of true-breeding parents

What is a purebred?

cellular respiration

What is an example of a catabolic pathway?

protein synthesis, amino acid synthesis

What is an example of an anabolic pathway?

a protein that penetrates (SPANS) the hydrophobic interior of the lipid bilayer; has N-terminus outside the cell, C-terminus inside the cell, and α helices

What is an integral protein?

an operon is a cluster of PROKARYOTIC, FUNCTIONALLY SIMILAR genes regulated by the same PROMOTER 1. operator [a segment to which a REGULATORY PROTEIN (ACTIVE/INACTIVE REPRESSOR) binds to affect the expression of the operon] 2. promoter [the site to which RNA POLYMERASE binds to begin transcription] 3. functional genes

What is an operon? What are its 3 parts?

a pH that is greater than 7

What is considered a basic pH?

pH=7

What is considered a neutral pH?

a pH that is less than 7

What is considered an acidic pH?

process whereby a protein unravels, loses its shape, & returns to its primary sequence

What is denaturation?

mating 2 contrasting TRUE-BREEDING varieties (ex: mating a purple true breeder with a white true breeder)

What is hybridization?

anything that has space and takes up mass

What is matter?

1. variations (mutations) 2. natural selection acts on these variations and picks the BEST ONE to survive (**both options could be TERRIBLE, but one has to be better than the other**)

What is the 2-step process for natural selection?

2 ATP (citric acid cycle) 6 CO₂ = 2 CO₂ (pyruvate ox.) + 4 CO₂ (citric acid cycle) 8 NADH = 2 NADH (pyruvate ox.) + 6 NADH (citric acid cycle) 2 FADH₂ (citric acid cycle)

What is the COMBINED NET YIELD of pyruvate oxidation and the citric acid cycle (DON'T INCLUDE GLYCOLYSIS)?

to produce gametes

What is the ENTIRE purpose of meiosis?

1:2:1:2:4:2:1:2:1 (1:2:1:2)(4)(2:1:2:1)

What is the GENOTYPIC ratio of a dihybrid cross?

1:2:1 (homozygous dominant to heterozygous to homozygous recessive)

What is the GENOTYPIC ratio of a monohybrid cross?

1 Glucose 2 ATPs

What is the NET INPUT of glycolysis?

2 pyruvates

What is the NET INPUT of pyruvate oxidation?

2 acetyl CoA's

What is the NET INPUT of the citric acid cycle?

4 ATP 6 CO₂ 10 NADH 2 FADH₂

What is the NET YIELD of cellular respiration BEFORE oxidative phosphorylation?

2 ATP = 4 ATP formed - 2 ATP used 2 NADH 2 pyruvates (3-carbon sugars)

What is the NET YIELD of glycolysis?

2 pyruvates (3-carbon sugars) 2 ATP = 4 ATP formed - 2 ATP used 2 NADH

What is the NET YIELD of glycolysis?

2 acetyl CoA (contains most energy) 2 CO₂ 2 NADH

What is the NET YIELD of pyruvate oxidation involving 1 glucose?

2 ATP 4 CO₂ 6 NADH 2 FADH₂

What is the NET YIELD of the citric acid cycle?

9:3:3:1

What is the PHENOTYPIC ratio of a dihybrid cross?

3:1 (dominant to recessive)

What is the PHENOTYPIC ratio of a monohybrid cross?

pH + pOH = 14 10 + pOH = 14 pOH = 4 [OH⁻] = 1 x 10⁻⁴

What is the concentration of OH⁻ ions in a solution where pH = 10?

• ANALOGOUS FEATURES: - share similar function, but not common ancestry • HOMOLOGOUS FEATURES - share common ancestry, but not necessarily similar function

What is the difference between analogous features and homologous features?

unlike the genes of a prokaryotic operon, which all share the SAME promoter and control elements... EACH coordinately controlled eukaryotic gene has ITS OWN promoter & control elements

What is the difference between coordinately controlled eukaryotic genes and the genes of a prokaryotic operon?

✰ DIVERGENT EVOLUTION ✰ • two related species share a common ancestor and therefore have similar structures (but not necessarily for the same function) ✰ CONVERGENT EVOLUTION ✰ • unrelated species independently develop similar traits to suit their similar environments

What is the difference between divergent evolution and convergent evolution?

GENERAL TRANSCRIPTION FACTORS: • proteins that help RNA polymerase bind to promoter • essential for the transcription of ALL protein-coding genes SPECIFIC TRANSCRIPTION FACTORS: • enhancers or repressors • proteins that help RNA polymerase bind to a PARTICULAR gene

What is the difference between general transcription factors and specific transcription factors?

HETEROCHROMATIN: TIGHTLY packed DNA → IS NOT expressed/transcribed EUCHROMATIN: LOOSELY packed DNA → IS expressed/transcribed *tip: the "oo" sound in EUchromatin sounds like the "oo" sound in the word "lOOse"

What is the difference between heterochromatin and euchromatin?

IN EUKARYOTES: • IN THE NUCLEUS, RNA polymerase synthesizes a pre-mRNA molecule ↓ • the pre-mRNA molecule is then MODIFIED through RNA PROCESSING in order to become a TRANSLATABLE mRNA molecule ↓ • TRANSLATABLE mRNA molecule then EXITS the nucleus through a nuclear pore ↓ • the mRNA is then TRANSLATED on a ribosome IN PROKARYOTES (🚫 NUCLEUS): • RNA polymerase synthesizes an mRNA molecule that is ready for translation on ribosomes (transcription and translation happen in SAME AREA) SUMMARY: • in eukaryotes, transcription and translation occur in SEPARATE areas in the cell; in prokaryotes, transcription and translation occur in the SAME area of the cell

What is the difference between transcription and translation in eukaryotes and prokaryotes?

p+q=1 → ALLELE frequency p²+2pq+q²=1 → % of INDIVIDUALS in a population that have a particular GENOTYPE

What is the different between p+q and the Hardy-Weinberg equation (p² + 2pq + q² = 1)?

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy

What is the equation for cellular respiration?

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy (ATP)

What is the equation for cellular respiration?

Light energy + 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

What is the equation for photosynthesis?

O₂

What is the final electron acceptor in aerobic respiration?

nitrate, sulfate, or CO₂ (inorganic molecules)

What is the final electron acceptor in anaerobic respiration?

pyruvic acid (organic molecule)

What is the final electron acceptor in fermentation?

DNA POLYMERASE I • REMOVES RNA primers • LAYS DOWN DNA where the RNA was AFTER DNA pol. III lays down DNA nucleotides

What is the function of DNA POLYMERASE I during DNA replication?

DNA POLYMERASE III • ATTACHES COMPLEMENTARY NUCLEOTIDES to daughter strands in 5'→3' direction

What is the function of DNA POLYMERASE III during DNA replication?

DNA POLYMERASE α • synthesizes the RNA primer • initiates DNA synthesis and the lagging strand

What is the function of DNA polymerase α in a eukaryotic cell?

DNA POLYMERASE δ • synthesizes the leading strand • fills DNA gaps after removal of primer

What is the function of DNA polymerase δ in a eukaryotic cell?

DNA POLYMERASE ε • repairs DNA

What is the function of DNA polymerase ε in a eukaryotic cell?

HELICASE • BREAKS hydrogen bonds and PULLS bases apart at the replication fork

What is the function of HELICASE during DNA replication?

LIGASE • SEALS the DNA backbone between the parental strand and the daughter strand

What is the function of LIGASE during DNA replication?

RNA PRIMASE • SYNTHESIZES a short RNA PRIMER complementary to the DNA nucleotide to INITIATE a new strand

What is the function of RNA PRIMASE during DNA replication?

SSBPs • PREVENTS DNA strands from RECOILING

What is the function of SINGLE-STRAND BINDING PROTEINS during DNA replication?

TELOMERASE • stops the shortening of telomeres by adding telomere repeats to the chromosome ends

What is the function of TELOMERASE during DNA replication?

TELOMERES • JUNK PIECES at end of linear DNA molecules, takes place of genes that could potentially be deleted as the DNA shortens

What is the function of TELOMERES during DNA replication?

TOPOISOMERASE: • UNWINDS DNA ahead of the replication fork

What is the function of TOPOISOMERASE during DNA replication?

SLIDING CLAMP • holds onto DNA pol. III • prevents DNA pol. III from dissociating from template strand

What is the function of the SLIDING CLAMP in DNA replication?

attaches to proteins and SIGNALS cell to DEGRADE that protein via proteasome

What is the function of ubiquitin?

DNA

What is the genetic material?

50%

What is the highest a recombination frequency can be?

peptide bond

What is the link formed by a dehydration synthesis reaction between the amino group of one amino acid and the carboxyl group of a second amino acid?

G₁; at this checkpoint, the cell decides if it wants to divide

What is the most important checkpoint in the cell cycle and what is its significance?

CIS side

What is the name of the RECEIVING side of the Golgi apparatus?

ribosome (synthesizes protein) → rough ER → transport vesicle that buds off RER and travels to cis side of Golgi apparatus

What is the path of a protein in a eukaryotic cell?

regulation

What is the point of RNA's that DO NOT make protein?

separate homologous chromosomes

What is the primary function of meiosis I?

recruit RNA polymerase to the promoter in order to initiate transcription (of ANY GENE)

What is the purpose of a general transcription factor in a eukaryote?

PREDICT the genotype of an individual with the dominant phenotype (by crossing it with a homozygous recessive individual)

What is the purpose of a testcross?

lacI is a regulatory gene that produces an mRNA that produces a lac repressor protein

What is the purpose of lacI?

• DEGRADE mRNA or BLOCK its translation • reduce the expression of their target genes

What is the purpose of miRNA's?

AUG

What is the start codon?

twice • in order to produce 2 acetyl CoA's, pyruvate oxidation must happen TWICE

What many times does pyruvate oxidation occur?

the catalytic knob

What part of ATP synthase creates ATP?

the nitrogenous base

What part of a nucleotide is not contained within the sugar-phosphate backbone?

glycolysis

What part of cellular respiration is NOT in the mitochondria?

Quaternary structure ✰ COLLAGEN ✰ • 40% of the protein in a human body • connective tissue • "glue producing" from Greek "kolla"

What protein structure is collagen?

Quaternary structure ✰ HEMOGLOBIN ✰ • found in red blood cells • carries oxygen, carries CO₂ back to your lungs so it can get removed • 2 α subunits + 2 β subunits

What protein structure is hemoglobin?

the cell's contents, which need enough room in order to function

What sets the lower limit of the size of a cell?

surface area-to-volume ratio

What sets the upper limit of the size of a cell?

lactose is an INDUCIBLE operon

What type of operon is lactose?

tryptophan is a REPRESSIBLE operon

What type of operon is tryptophan?

When 2 genes have the same control elements, they turn on at THE SAME time

When 2 genes have the same control elements, they turn on at ___________ time

anaphase II

When do sister chromatids separate in meiosis?

When glucose levels are LOW, cAMP levels are HIGH, resulting in ACTIVE CAP & INCREASED transcription

When glucose levels are LOW, cAMP levels are ________, resulting in ACTIVE CAP & ___________ transcription

When there are two alleles for a gene in a population, their frequencies are given the symbols p (DOMINANT alleles) and q (RECESSIVE alleles)

When there are two alleles for a gene in a population, their frequencies are given the symbols p (_________ alleles) and q (_________ alleles)

in the thylakoid membrane

Where are photosystems located?

- eukaryotic cells have ribosomes in the cytosol & the RER - prokaryotic cells ONLY have ribosomes in the cytosol

Where are ribosomes located in eukaryotic cells? In prokaryotic cells?

in eukaryotes: in the rough ER/cytosol in prokaryotes: in the cytosol

Where can ribosomes be located?

hippos and sharks • as you move backwards from the tips, hippos and sharks converge at a common ancestor BEFORE hippos and deer converge at a common ancestor

Which are more closely related: deer and hippos, or hippos and sharks?

adenine, guanine

Which bases are PURINES?

thymine, cytosine, uracil

Which bases are PYRIMIDINES?

lipids

Which macromolecule is NOT made of monomers?

the endoplasmic reticulum (ER)

Which organelle determines a membrane's sidedness?

the operator (b/c it's where the REPRESSOR binds)

Which part of an operon determines whether RNA polymerase can transcribe?

prokaryotes

Which were seen first: eukaryotes or prokaryotes?

✰ CARL LINNAEUS (mid-1700's) ✰ • founder of TAXONOMY • categorized organisms based on SIMILARITIES in features • created the BINOMIAL NAMING SYSTEM • said resemblances between organisms were due to PATTERN OF THEIR CREATION (**🚫 due to evolution, which HAD NOT BEEN PROPOSED YET**)

Who was Carl Linnaeus? (4)

✰ CHARLES LYELL ✰ • geologist • said that geology (strata) were explained by GRADUAL MECHANISMS

Who was Charles Lyell? (2)

✰ GEORGE CUVIER ✰ • paleontologist • explained fossils as CATASTROPHIC EXTINCTION • following this, the area was repopulated with things from other areas

Who was George Cuvier (3)?

Lamarck

Who was the 1st to state that organisms evolve?

1. selection can only act on EXISTING variations 2. evolution is LIMITED by historical constraints (that is, it operates on traits an organism already HAS, it doesn't just start from scratch to build a new feature) 3. adaptations are often COMPROMISES 4. chance, natural selection, and the environment INTERACT

Why can't natural selection create perfect individuals?

because nonpolar molecules are uncharged, and water will not be able to form a hydration shell

Why can't nonpolar molecules dissolve in water?

the inner portion of the plasma membrane's lipid bilayer is hydrophobic, so a polar (hydrophilic) molecule trying to cross through a nonpolar (hydrophobic) region is THERMODYNAMICALLY UNFAVORABLE

Why can't polar molecules easily cross the plasma membrane?

the genes were linked on the same chromosome, and therefore they were inherited TOGETHER (due to bypassing independent assortment)

Why didn't Morgan consistently yield a 3:1 ratio during his fly experiments?

a eukaryotic cell can only divide so many times until it runs out of TELOMERES

Why does a eukaryotic cell have a finite lifespan?

• increased H₂O uptake allows the plasma membrane to exert pressure on the cell wall, thus allowing the 🌿 to stay upright • therefore, WITHOUT H₂O, there will be less outward pressure, and the cell will SHRIVEL as the plasma membrane PULLS AWAY from the cell wall (PLASMOLYSIS)

Why does a plant wilt if you don't water it?

because our genes are turned on and off at different times

Why don't humans resemble chimps even though we are 98-99% genetically similar?

such bacteria can conserve energy and resources

Why has natural selection favored bacteria that express only the genes whose products are needed by the cell?

if allele frequencies change between generations, then evolution is occurring

Why is allele frequency important to evolution?

• multicellular eukaryotes produce large numbers and types of cells • nuclear DNA is organized with histones into chromatin

Why is gene regulation more complicated in eukaryotes than in prokaryotes?

because genetic drift can lead to loss of genetic variation, loss of rare alleles, and can cause harmful alleles to become fixed

Why is genetic drift often harmful to relative fitness (3)?

if the cell grows beyond a certain limit, not enough material will be able to cross the membrane fast enough to accommodate the increased cellular volume; as a result, the cell wouldn't be able to bring nutrients in or take waste out fast enough, which would lead to a build up of waste, which would eventually kill the cell

Why is it important that a cell have a large surface area relative to its volume?

because RNA polymerase CAN'T access the promoter

Why is tightly packed DNA (condensed chromatin) difficult to express?

[H⁺][OH⁻] = 10⁻¹⁴ pH + pOH = 14 * brackets indicate molar concentration

LOW levels of glucose activate CAP • LOW glucose → HIGH cAMP → ACTIVE CAP → CAP binds to binding site → INCREASED transcription

_____ levels of glucose activate CAP.

LOW levels of lactose activate lacI. • LOW lactose → LOW allolactose → ACTIVE lacI → BOUND lac repressor → OFF operon

_____ levels of lactose activate lacI

steroids

_______ are a group of lipids with structures based on a framework of four carbon rings

dihybrid cross

a genetic cross between two individuals that are each HETEROZYGOUS for DIFFERENT pairs of alleles

monohybrid cross

a genetic cross between two individuals that are each HETEROZYGOUS for the SAME PAIR OF ALLELES

acetylation (acetyl groups + histone tails) → LOOSER chromatin structure → INCREASED access to DNA → INCREASED transcription

acetylation (acetyl groups + histone tails) → __________ chromatin structure → INCREASED access to DNA → INCREASED transcription

recombination frequency

how likely it is that CROSSING OVER will split chromosomes apart; the percentage of testcross progeny that are recombinants

methylation (methyl groups + histone tails) → TIGHTER chromatin structure → DECREASED access to DNA → DECREASED transcription

methylation (methyl groups + histone tails) → ___________ chromatin structure → DECREASED access to DNA → DECREASED transcription

feedback inhibition

mode of metabolic control in which the product of a reaction acts as a regulator of the reaction

chaperone proteins

proteins that direct the conformation of a newly synthesized protein toward the correct TERTIARY structure [basically, they help the protein fold or refold (after denaturation) correctly]

codominance

situation in which BOTH ALLELES are SIMULTANEOUSLY EXPRESSED as DOMINANT in a heterozygote

incomplete dominance

situation in which phenotypes of dominant and recessive alleles are mixed in heterozygotes

complete dominance

situation in which the phenotypes of the HETEROZYGOTE (Pp) and DOMINANT HOMOZYGOTE (PP) are INDISTINGUISHABLE

6(a²)

surface area of cube

genetic recombination

the process by which the alleles for different genes in two parental individuals become shuffled in offspring individuals

operator

the regulatory "switch"; a short segment to which a REGULATORY PROTEIN (ACTIVE/INACTIVE REPRESSOR) binds to affect the expression of the operon

promoter

the site to which RNA POLYMERASE binds to begin transcription

ℓwh (or a³)

volume of cube

Van der Waals interactions

weak molecular attractions over short distances

• A radioactive isotope is one in which the nucleus DECAYS spontaneously, giving off particles and energy • Radioactive isotopes decay at a DEFINED RATE called the HALF-LIFE

• The idea behind a chemical bond & any bond is connected to filling an atom's valence shell

✰ 1. ADHESION/COHESION ✰ • Adhesion: the clinging of unlike substances • Cohesion: the clinging of like substances (ex: hydrogen bonds) ("co-" together, with) - Surface tension: a measure of how difficult it is to stretch or break the surface of a liquid

✰ 1. GLYCOLYSIS ✰ • WHERE? ➡ cytosol • FUNCTION? ➡ break down glucose 1. ENERGY INPUT PHASE (anabolic) • NET: glucose (splits in half) ➡ 2 pyruvate (3-carbon sugars) + 2 ATP + 2 NADH 2. ENERGY OUTPUT PHASE (catabolic) • the energy payoff phase occurs TWICE per molecule of glucose • PYRUVATES contain MOST of the energy from glucose • GLYCOLYSIS does NOT require oxygen • produces ATP through SUBSTRATE-LEVEL PHOSPHORYLATION

✰ 2. MODERATION OF TEMPERATURE ✰ • Heat: kinetic energy (energy of movement) transfer • Specific heat of a substance: amount of heat that must be absorbed or lost for 1 g of that substance to change its temperature by 1°C (how fast a substance gets hotter) - high specific heat = more heat required - low specific heat = less heat required • Water has VERY HIGH specific heat due to hydrogen bonds (ex: if you put an iron pot full of water on a stove and let it sit, the pot will be hotter than the water b/c the water requires MUCH MORE HEAT than the pot for its temperature to increase) • Allows life - prevents people from getting too hot too quickly (due to hydrogen bonds in the water in our cells) - coastal temperatures near oceans have less drastic temperature changes vs. anywhere else (heat from sun will go towards breaking hydrogen bonds in ocean and warming the water instead of warming the air)

✰ 2a. PYRUVATE OXIDATION ✰ • WHERE? ➡ mitochondrial matrix • FUNCTION? ➡ extract remaining energy from pyruvates by OXIDIZING pyruvates to yield acetyl CoA • NET: 2 pyruvates (from ONE glucose) ➡ 2 acetyl CoA + 2 CO₂ + 2 NADH (reduced form of NAD⁺)

✰ 2b. CITRIC ACID CYCLE ✰ • WHERE? ➡ mitochondrial matrix • FUNCTION? ➡ break down two 2-carbon acetyl CoA's and take out the remaining energy • produces ATP through SUBSTRATE-LEVEL PHOSPHORYLATION

✰ 3. EXPANSION UPON FREEZING ✰ • Water is one of the few substances that are less dense as a solid than as a liquid • Hydrogen bonds in ice are more "ORDERED" than in liquid water (molecules in ice are FURTHER APART and MORE STABLE than molecules in liquid water) → ice is less dense (less packed together) and has FEWER MOLECULES → therefore, ice floats on liquid water • Why is this important? - if ice were DENSER than liquid water, it would sink to the bottom - if ice sank, then eventually all ponds, lakes, & oceans would freeze solid, making life as we know it impossible on Earth

✰ 4. Water as a versatile solvent ✰ • Water is a very versatile solvent • In an aqueous (ℓ) solution, water is the solvent • Why is this important? - 70-80% of our bodies are water (ex: cytoplasm in our cells is primarily water, & everything in our cell must then dissolve in the cytoplasm) • How do substances dissolve in water? - H₂O molecules have partial charges - when substances go into water, water molecules form a HYDRATION SHELL around dissolved ions • Many nonionic POLAR (CHARGED) molecules (i.e., sugars) are water-soluble • Many large POLAR (CHARGED) molecules with ionic/polar regions (i.e., proteins) are water-soluble • Nonpolar molecules (i.e., oil, lipid) are INSOLUBLE in water

✰ ACTIVATION ENERGY BARRIER ✰ • ACTIVATION ENERGY [E(a)]: the amount of energy needed to PUSH reactants UPHILL to the top of an ENERGY BARRIER, so that the DOWNHILL part of the reaction can begin ↓ • the reactants must absorb ENOUGH E(a) from their surroundings in order to reach an UNSTABLE TRANSITION STATE where their BONDS can finally BREAK ↓ • at the TRANSITION STATE, NEW BONDS form and RELEASE energy to surroundings

✰ ACTIVE SITE ✰ • FUNCTION: LOWER the E(a) by: - orienting substrate correctly - straining substrate bonds - covalently bonding to substrate • all of these methods make bonds MORE LIKELY TO SHIFT and therefore make the reactant MORE LIKELY TO CHANGE

✰ ADAPTIVE EVOLUTION ✰ ✪ process in which alleles that improve FITNESS INCREASE in frequency over time

✰ ADAPTIVE EVOLUTION ✰ ✪ process in which alleles that improve __________ INCREASE in frequency over time

✰ ADDITION OF A NUCLEOTIDE TO A DNA STRAND ✰ • in order for a free DNA nucleotide to be added onto a DNA strand, 1. complementary bases MUST bind to each other 2. the nucleotide MUST be added to the 3' OH end of the chain • DNA polymerase CATALYZES the addition of the nucleotide, RELEASING TWO PHOSPHATES in the process

✰ ADDITIONAL CHROMOSOMES ✰ • nondisjunction → ANEUPLOIDY • abnormal # of a particular chromosome • POLYPLOIDY: >2 sets of chromosomes - TRIPLOIDY (3n) - TETRAPLOIDY (4n)

No, due to the force of gravity. • HOWEVER, adhesion/cohesion can allow water to act AGAINST gravity

✰ ADHESION/COHESION THOUGHT EXPERIMENT ✰ • Imagine you have a bucket of water with a giant tube halfway submerged in the bucket. Would the water just naturally move from the bucket, up the tube, and to the top?

✰ ALCOHOLIC FERMENTATION ✰ • NET YIELD: 2 ATP • glycolysis happens AS NORMAL • NADH reduces the 2 pyruvates from glycolysis to form ETHANOL and REGENERATE NAD⁺ (REDOX) (• WITHOUT O₂, NADH will NOT be able to be oxidized to NAD⁺ and oxidative phosphorylation WILL NOT OCCUR • eventually, NADH's will ACCUMULATE in the cell, NAD⁺ will decrease, and glycolysis will CEASE (b/c it needs NAD⁺), then ATP will stop being made, and the CELL WILL EVENTUALLY DIE

✰ ALFRED RUSSELL WALLACE ✰ • pushed Darwin to publish "Origin of Species"

✰ ALLOPATRIC SPECIATION ✰ • a physical barrier cuts off GENE FLOW between two geographically separated populations → over long period of time, unequal mutations and unequal selection pressures will cause the two populations to be incapable of MATING with each other

✰ ALLOPATRIC SPECIATION ✰ • allopatric = different homeland • a physical barrier cuts off __________ between two geographically separated populations → over long period of time, unequal mutations and unequal selection pressures will cause the two populations to be incapable of MATING with each other

✰ ALTERATIONS OF CHROMOSOME NUMBER OR STRUCTURE ✰ • large-scale chromosomal alterations → miscarriage or developmental disorders • NONDISJUNCTION: the FAILURE of homologous chromosomes to PROPERLY SEPARATE during meiosis I or the FAILURE of sister chromatids to PROPERLY SEPARATE during meiosis II - nondisjunction → gametes with ABNORMAL chromosome number

✰ ALTERATIONS OF CHROMOSOME STRUCTURE ✰ • Chromosome breakage can lead to FOUR types of changes - Deletion - Duplication - Inversion - Translocation

✰ ANAEROBIC RESPIRATION ✰ • some microbes & species of bacteria go through this • final electron acceptor is NOT O₂... it's nitrate/sulfur/CO₂ • NOT as common as aerobic respiration

✰ ANAPHASE I ✰ • HOMOLOGOUS CHROMOSOMES SEPARATE!!!! • sister chromatids remain ATTACHED (think of butterflies, whereas when the sister chromatids in mitosis are pulled apart, they look like boomerangs)

✰ ANAPHASE II ✰ • SISTER CHROMATIDS SEPARATE & move toward opposite ends of the cell

✰ ANAPHASE ✰ • SISTER CHROMATIDS come apart, and each chromatid becomes an INDEPENDENT DAUGHTER CHROMOSOME • each new DAUGHTER CHROMOSOME is now pulled to opposite ends of the cell as their KINETOCHORE MICROTUBULES shorten • cell elongates as NONKINETOCHORE MICROTUBULES lengthen • by the end of anaphase, the two ends of the cell have EQUIVALENT amounts of daughter chromosomes

✰ ANEUPLOIDY OF SEX CHROMOSOMES ✰ • nondisjunction of sex chromosomes → varied ANEUPLOID conditions • KLINEFELTER SYNDROME: - male with XXY - less testosterone, less body hair, broader hips • TURNER SYNDROME: - female with X0 (missing an X chromosome) - sterile, wide neck, shorter & broader neck

✰ ARISTOTLE (300 B.C.) ✰ • organized organisms on a linear "scala natura" (w/HUMANS at the top) • hypothesized that every organism is PERFECT and UNCHANGING

✰ ARISTOTLE (300 B.C.) ✰ • organized organisms on a linear _____________ (w/______ at the top) • hypothesized that every organism is ________ and __________

✰ ARTIFICIAL SELECTION ✰ • PEOPLE do the selecting, 🚫 the environment

✰ ATP (ADENOSINE TRIPHOSPHATE) ✰ • ribose + adenine + 3 phosphate groups • the bond between the 2nd and 3rd phosphate releases a lot of energy when broken down by HYDROLYSIS

✰ ATP PRODUCTION ✰ • catabolic pathways yield energy by OXIDIZING ORGANIC FUELS in chemical reactions • during these chemical reactions, electrons are TRANSFERRED (redox) • this transfer of electrons RELEASES ENERGY stored in these organic fuels • this RELEASED ENERGY is used to SYNTHESIZE ATP

✰ BACTERIAL REPLICATION ✰

✰ BARRIERS TO SPECIATION ✰ ✪ Why not just one species? • FIVE prezygotic (up to AND including MATING ATTEMPT) • THREE postzygotic (formation of HYBRID ZYGOTES)

✰ BARRIERS TO SPECIATION ✰ ✪ Why not just one species? • FIVE prezygotic (up to AND including _________) • THREE postzygotic (formation of _________)

✰ BINARY FISSION IN PROKARYOTES (BACTERIA) ✰ • prokaryotes have LESS DNA than eukaryotes • DNA replication happens at SAME TIME as DNA separation • FtsZ proteins form in middle of cell to direct cleavage formation

✰ BUFFERS ✰ • The internal pH of most living things must remain close to pH 7 (our blood is pH 7.4) - even slight changes in pH can be harmful • a buffer: substance that keeps a solution at a relatively constant pH (minimizes changes in [H⁺] and [OH⁻] in a solution) - a buffer keeps the pH constant by accepting hydrogen ions from the solution when they are in excess and donating hydrogen ions to the solution when they have been depleted

✰ CALVIN CYCLE (ANABOLIC)✰ • WHERE? → stroma • FUNCTION? → take energy from light reactions (in form of ATP and NADPH) to reduce inorganic CO₂ to organic sugar G3P

✰ CALVIN CYCLE (ANABOLIC)✰ • for synthesis of one G3P, the cycle must repeat 3x, with each turn yielding 1 CO₂ for a total of 3 CO₂'s 3 PHASES: 1) CARBON FIXATION - Calvin cycle attaches an inorganic CO₂ to RUBISCO (5-carbon sugar) to form 2 molecules of 3-PGA 2) REDUCTION - 6 NADPH's and 6 ATP's reduce (NADPH→NADP⁺) two 3-PGA to produce 1 G3P 3) REGENERATION - regenerate starting material (three molecules of 5-carbon RuBP) using 3 ATP's

✰ CAM 🌿✰ (i.e., pineapples) • minimizes photorespiration by temporally separating the light-dependent reactions and the use of CO₂ in the Calvin cycle in space 1) NIGHT • stomata OPEN to allow CO₂ in, CO₂ is fixed by PEP carboxylase to form a 4-carbon sugar, which is then stored as an ORGANIC ACID (malate) 2) DAY • stomata CLOSE, malate breaks down to form CO₂ that then proceeds through the Calvin cycle

✰ CANCER GENES ✰ • PROTO-ONCOGENES (car accelerators) → normally PROMOTE NORMAL growth... if you imagine you have 2 car accelerators, a mutation in ONE photo-oncogene will convert it to an ONCOGENE (genes that cause cancer) • TUMOR-SUPPRESSOR GENES (car brakes) → normally RESTRAIN growth... if you imagine you have 2 car brakes, loss of function in BOTH genes results in UNREGULATED GROWTH • DNA REPAIR GENES → activated at end of G₂ or in S; make sure genome has been replicated correctly... faulty DNA repair genes lead to ACCUMULATED RATE OF MUTATIONS

✰ CANCER GENES ✰ • cancer genes create a cell that has accumulated mutations in specific GENE FAMILIES (i.e., the cell cycle, adhesion, apoptosis, DNA repair)

✰ CARL LINNAEUS (mid-1700's) ✰ • founder of TAXONOMY • categorized organisms based on SIMILARITIES in physical characteristics (morphologies) • created the BINOMIAL NAMING SYSTEM • said resemblances between organisms were due to PATTERN OF THEIR CREATION (**🚫 due to evolution, which HAD NOT BEEN PROPOSED YET**)

✰ CARL LINNAEUS (mid-1700's) ✰ • founder of _________ • categorized organisms based on _________ in physical characteristics (morphologies) • created the ____________ • said resemblances between organisms were due to ______________

✰ CATABOLIC/ANABOLIC PATHWAYS ✰ • CATABOLIC PATHWAYS (i.e., cellular respiration): DEGRADATIVE process by which a pathway RELEASES ENERGY by breaking down complex molecules to simpler compounds • ANABOLIC PATHWAYS (i.e., protein synthesis, amino synthesis): process by which a pathway ABSORBS ENERGY to build complex molecules from simpler ones

✰ CATABOLITE ACTIVATOR PROTEIN (CAP) ✰ HIGH levels of glucose ↓ LOW levels of cAMP ↓ INACTIVE CAP, which DETACHES FROM the promoter at the CAP binding site ↓ Affinity of RNA polymerase DECREASES ↓ Transcription DECREASES, even if lactose is PRESENT

✰ CATABOLITE ACTIVATOR PROTEIN (CAP) ✰ HIGH levels of glucose ↓ ____ levels of cAMP ↓ _______ CAP, which ___________ the promoter at the CAP binding site ↓ Affinity of RNA polymerase ________ ↓ Transcription ________, even if lactose is ________

✰ CATABOLITE ACTIVATOR PROTEIN (CAP) ✰ LOW levels of glucose ↓ HIGH levels of cAMP ↓ ACTIVE CAP, which BINDS TO the promoter at the CAP binding site ↓ Affinity of RNA polymerase INCREASES ↓ Transcription INCREASES

✰ CATABOLITE ACTIVATOR PROTEIN (CAP) ✰ LOW levels of glucose ↓ ____ levels of cAMP ↓ _______ CAP, which ________ the promoter at the CAP binding site ↓ Affinity of RNA polymerase __________ ↓ Transcription _________

✰ CATEGORIES OF CELLS ✰ • NOT all cells go through cell cycle - ex: red blood cells (they don't go through cycle b/c they don't have a nucleus and therefore no DNA) • some cells can be induced to divide when stimulated - ex: lymphocytes • some cells have a high level of division - ex: cancer cells, stem cells

✰ CELL DIVISION ✰ • PROKARYOTES: binary fission • EUKARYOTES: mitosis (asexual reproduction)

✰ CELLULAR WORK ✰ • 3 major kinds of cellular work, ALL MEDIATED BY ATP: - transport (i.e., Na-K pump) - mechanical (i.e., motor protein moving along cytoskeleton track) - chemical (i.e., synthesizing polymers from monomers... replicating DNA by stringing nucleotides into nucleic acids) • ENERGY COUPLING: the use of an exergonic process to DRIVE an endergonic one; MEDIATED BY ATP AS WELL

✰ CHARLES DARWIN & THE ORIGIN OF SPECIES ✰ • in his Origin of Species, Charles Darwin made THREE observations: - patterns of similarities - diversity of life - how individuals fit w/the environment (i.e., camouflage)

✰ CHARLES DARWIN ✰ ✪ during his voyage on the HMS Beagle, Darwin collected specimens of South American 🌿 and 🐖 ✪ OBSERVATIONS: - fossils resembled LIVING SPECIES - living species resembled species from NEARBY AREAS ✪ ISLAND SPECIATION (🐦 with different beaks on the Galápagos Islands)

✰ CHARLES DARWIN ✰ ✪ during his voyage on the HMS Beagle, Darwin collected specimens of South American 🌿 and 🐖 ✪ OBSERVATIONS: - fossils resembled ___________ - living species resembled species from _________ ✪ ISLAND SPECIATION (🐦 with different beaks on the Galápagos Islands)

✰ CHARLES LYELL ✰ • geologist • said that geology (strata) were explained by GRADUAL MECHANISMS

✰ CHARLES LYELL ✰ • geologist • said that geology (strata) were explained by _____________

✰ CHECKPOINTS OF CELL ✰ • G₁ (*MOST IMPORTANT*) → cells DECIDES if it wants to replicate • G₂ → cell ASSESSES whether its DNA was replicated correctly, checks for DAMAGE • M → cell ENSURES that all of its chromosomes are bound to kinetochores and lined up in the middle evenly

✰ CHEMICAL BONDS ✰ • A chemical bond is a bond formed when atoms combine to form molecules & ionic compounds in order to complete their valence shells ⇨ this also explains why not every element can bond with everything else, b/c if the bond won't complete the shell, then the element can't bond to something else • During the formation of a chemical bond, atoms can share or transfer (or steal) electrons

✰ CHLOROPLASTS ✰ • have INNER & OUTER MEMBRANE • GRANA (stacks) of THYLAKOIDS (green disks) • STROMA: empty space

✰ CHROMOSOMAL BASIS OF SEX ✰ •♀️- XX •♂️- XY • X CHROMOSOME - larger - default sex chromosome - primarily code for NONSEXUAL traits • Y CHROMOSOME - smaller - primarily sex-related traits • SRY gene on Y chromosome can ACTIVATE Y and lead to the development of testes (the absence of SRY → ovaries)

✰ CHROMOSOMES ✰ • CHROMOSOMAL THEORY OF INHERITANCE (discovered by Thomas Hunt Morgan) - genes have specific LOCI on chromosomes - these chromosomes undergo segregation & independent assortment • explains all of Mendel's ideas

✰ CODON TABLE ✰ • AUG: out of 64 codons, THIS ONE functions as the START CODON, signaling when ribosomes should START TRANSLATION • UAA, UAG, UGA: out of 64 codons, these THREE function as STOP CODONS, signaling when ribosomes should END TRANSLATION • out of 64 codons, 61 of them LAY DOWN AMINO ACIDS • REDUNDANCY: there are 21 amino acids for which there are multiple codons - this can make it HARDER for a mutation to alter a protein

✰ COMPLEMENTARY BASE PAIRING ✰ in DNA: • ADENINE (A) forms TWO hydrogen bonds with THYMINE (T) • GUANINE (G) forms THREE hydrogen bonds with CYTOSINE (C) in RNA: • ADENINE (A) forms TWO hydrogen bonds with URACIL (U) • GUANINE (G) forms THREE hydrogen bonds with CYTOSINE (C)

✰ COMPLETING THE PROTEIN ✰ • after the polypeptides detach from ribosomes, they are NOT ready for use... that is, translation is NOT sufficient • in order for a protein to be functional, the following must happen: - it must FOLD into the correct structure - it may need to be MODIFIED in the RER or Golgi - it will need to be TRANSPORTED by a transport vesicle to the correct location in the cell

✰ COORDINATELY CONTROLLED GENES ✰ • co-expressed eukaryotic genes have their own PROMOTERS and CONTROL ELEMENTS • co-expressed eukaryotic genes can be scattered across different CHROMOSOMES, but each has the SAME # of CONTROL ELEMENTS • when 2 genes have the same control elements, they turn on at THE SAME time • in the picture, the expression of the coordinately controlled albumin and crystalline genes in liver cells and lens cells depends on the signals and the SPECIFIC TRANSCRIPTION FACTORS that are present

✰ COORDINATELY CONTROLLED GENES ✰ • co-expressed eukaryotic genes have their own __________ and _________ • co-expressed eukaryotic genes can be scattered over different __________, but each gene has the same #/combination of ______________ • when 2 genes have the same control elements, they turn on at ___________ time • in the picture, the expression of the coordinately controlled albumin and crystallin genes in liver cells and lens cells depends on the signals and the _____________ that are present

✰ COVALENT BONDS ✰ • A covalent bond is a bond formed by two atoms sharing a pair of VE's

✰ CROSSING OVER ✰ • CROSSING OVER → homologous portions of NON-SISTER chromatids TRADE PLACES • occurs **ONLY IN MEIOSIS** • occurs during **PROPHASE I** as homologous chromosomes pair up

✰ CYTOKINESIS ✰ • cleavage furrow pinches the cell into 2 new cells

✰ C₃ 🌿✰ • normal pathway for photosynthesis (use of rubisco to fix CO₂) • C₃'s first sugar is a 3-carbon sugar

✰ C₄ 🌿✰ (i.e., sugarcane) • minimizes photorespiration by spatially separating 2 different cells 1) mesophyll cell (HIGH O₂) • an enzyme called PEP CARBOXYLASE (which does NOT bind with O₂) reacts with CO₂ to form a 4-carbon sugar which is then stored as an ORGANIC ACID (malate) 2) bundle sheath (HIGH CO₂) • malate from the mesophyll breaks back down into CO₂, which is then fixed by RUBISCO to produce sugars and continue photosynthesis as usual

✰ DARWIN'S THEORY OF NATURAL SELECTION ✰ • TWO 🔑 observations: ✪ OVERPRODUCTION & COMPETITION (all species produce MORE offspring than environment can handle → competition for available resources) + ✪ INDIVIDUAL VARIATION (variation exists among individuals in a population; much of this variation is HERITABLE) ↓ ✪ RESULT: UNEQUAL REPRODUCTIVE SUCCESS ↓ individuals with traits best suited to local environment leave a LARGER share of surviving, fertile offspring ↓ THIS IS NATURAL SELECTION

✰ DEGREES OF DOMINANCE ✰ • inheritance may DEVIATE from simple Mendelian patterns • COMPLETE DOMINANCE: situation in which the phenotypes of the HETEROZYGOTE (Pp) and DOMINANT HOMOZYGOTE (PP) are INDISTINGUISHABLE • CODOMINANCE: situation in which BOTH ALLELES are SIMULTANEOUSLY EXPRESSED as DOMINANT in a heterozygote - I(A), I(B), I(C) - I(A)I(B)= type AB - I(A)I(O)= type A - I(O)I(O)= type O * O is recessive to A & B • INCOMPLETE DOMINANCE: situation in which phenotypes of dominant and recessive alleles are BLENDED in heterozygotes (i.e., pink snapdragons) - genotypic ratio=phenotypic ratio

✰ DELETION ✰ • occurs when a chromosomal fragment is LOST

✰ DETERMINATION OF SEX ✰ • in mammals, the sex of an offspring depends on whether the SPERM cell carries an X or a Y

✰ DNA REPLICATION ✰ • process of taking genome & copying it • occurs with amazing speed & accuracy • >12 enzymes • ORIGIN OF REPLICATION: where replication starts • REPLICATION "BUBBLE": open pucker between "unzipped" DNA strands • REPLICATION FORK: Y-shaped region where parental strands of DNA are being unwound

✰ DNA SYNTHESIS ON THE LAGGING STRAND ✰ • on the lagging strand, replication is DISCONTINUOUS → replication done in a series of segments (OKAZAKI FRAGMENTS) 1. RNA primase lays down RNA primer 2. DNA pol. III lays down complementary nucleotides onto the primer in the OPPOSITE DIRECTION that helicase unwinds (in other words, the enzyme moves AWAY FROM helicase), forming Okazaki fragment 1 3. Process continues until LIGASE seals backbones between DNA fragments

✰ DNA SYNTHESIS ON THE LEADING STRAND ✰ • on the leading strand, replication is CONTINUOUS 1. RNA primase lays down RNA primer 2. DNA pol. III lays down complementary nucleotides onto the primer IN THE SAME DIRECTION that helicase unwinds (in other words, the enzyme moves TOWARD helicase) 3. The leading strand is continuously elongated in the 5'→3' direction

✰ DNA ✰ • is ANTIPARALLEL • has a SUGAR-PHOSPHATE BACKBONE (held together by PHOSPHODIESTER BONDS) • bases are held together by HYDROGEN BONDS • there are 10 BASE PAIRS per full turn of the helix

✰ DNA ✰ • there is approx. 6 FEET of DNA in EACH of our cells • CENTRAL DNA is wrapped around EIGHT histone molecules and then LINK DNA bonds to histone H1

✰ DOMINANT VS. RECESSIVE ✰ Mendel determined the following: • purple flower trait was DOMINANT • white flower trait was RECESSIVE • the "heritable invisible factor" was a GENE

✰ DOMINANTLY INHERITED DISORDERS ✰ • i.e., polydactyly, Huntington's disease • some human disorders are caused by DOMINANT alleles

✰ DOWN SYNDROME ✰ • one EXTRA chromosome 21

✰ DUPLICATION ✰ • occurs when a segment is REPEATED

✰ EACH DNA STRAND HAS TWO DISTINCT ENDS ✰ 1) the 5' end has an exposed phosphate group attached to the 5'-carbon of the sugar 2) the 3' end has an exposed hydroxyl group attached to the 3'-carbon of the sugar.

✰ ELECTRON CARRIERS ✰ • FUNCTION: hold energy taken from GLUCOSE until it can be used to synthesize ATP • NAD⁺ (empty) → NADH (loaded; reduced) • FAD⁺ (empty) → FADH₂ (loaded; reduced)

✰ ELECTRON TRANSPORT CHAIN, PT.1 ✰ • WHERE? ➡ in cristae on mitochondrial membrane • NADH & FADH₂ pass their electrons ↓ the electron transport chain to LOWER energy levels, RELEASING energy as they move • ex: NADH donates an electron (becoming NAD⁺) to complex I → the electron moves through the different proteins within complex I → then attaches to Ubiquinone (mobile carrier protein) → complex III, etc. - an electron will either move from I→III→IV or from II→III→IV • Ubiquinone (mobile carrier protein, nonpolar molecule) carriers (e⁻) I/II→III • Cytochrome c (mobile carrier protein, nonpolar molecule) carries (e⁻) III→IV • @ final step, OXYGEN is the FINAL ELECTRON ACCEPTOR (b/c it is the MOST ELECTRONEGATIVE molecule in the electron transport chain)

✰ ENDERGONIC REACTIONS ✰ • i.e., photosynthesis • reactants are low energy, products are HIGH energy • +∆G • ABSORBS ENERGY INTO SYSTEM • ANABOLIC THINK: ENDERGONIC: low → HIGH ANABOLIC: simple → COMPLEX

✰ ENERGY ✰ • at the end of the citric acid cycle, the majority of energy from glucose is in NADH (NOT IN ATP) which can later be OXIDIZED to produce ATP (i.e., NADH→NAD⁺). . . this catabolic process is OXIDATIVE PHOSPHORYLATION • this energy goes

✰ ENVIRONMENTAL FACTORS AFFECTING ENZYMES ✰ • enzymes are proteins, so they can be affected by denaturation & environmental factors • enzymes have OPTIMAL conditions - they work in specific range of temperatures and pH

✰ ENZYMES ✰ • SUBSTRATE: the REACTANT an enzyme binds to • ACTIVE SITE: space ON AN ENZYME WHERE an enzyme binds to a substrate • ENZYME SPECIFICITY: an enzyme's active site is SPECIFIC for a particular substrate • enzymes are usually in VERY VERY SMALL amounts in cells b/c they can be REUSED to form NEW PRODUCTS

✰ EPIGENETIC INHERITANCE ✰ • inheritance of traits by mechanisms NOT involving the NUCLEOTIDE sequence • are REVERSIBLE (UNLIKE DNA mutations) • does NOT alter DNA sequence (i.e., methylation/acetylation) • CAN be passed on • explains differences in identical twins (i.e., the twins in space) • epigenetic are caused by the ENVIRONMENT you live in

✰ EPIGENETIC INHERITANCE ✰ • inheritance of traits by mechanisms NOT involving the __________ sequence • are ___________ (UNLIKE DNA mutations) • does NOT alter _____ sequence (i.e., methylation/acetylation) • CAN be passed on • explains differences in identical twins (i.e., the twins in space) • epigenetic are caused by the ____________ you live in

✰ EUKARYOTE DNA POLYMERASES ✰ • eukaryotic cells contain SEVERAL types of DNA polymerases (more than a dozen!!) - α: synthesizes the RNA primer, initiates DNA synthesis and the lagging strand - δ: synthesizes the leading strand, fills DNA gaps after removal of primer - ε: repairs DNA • eukaryotic cells involve MORE ENZYMES

✰ EUKARYOTES ✰ • differential gene expression is ESSENTIAL for cell SPECIALIZATION • in eukaryotes, there are MORE OPTIONS FOR REGULATION than in prokaryotes • eukaryotic gene expression is regulated at MANY STAGES

✰ EUKARYOTES ✰ • differential gene expression is ESSENTIAL for cell __________ • in eukaryotes, there are MORE OPTIONS FOR ____________ than in prokaryotes • eukaryotic gene expression is regulated at MANY _________

✰ EUKARYOTES: REGULATION OF TRANSCRIPTION INITIATION ✰ • eukaryotes do NOT have OPERONS!!! • GENERAL TRANSCRIPTION FACTORS: bind 1st to promoter then RECRUIT RNA polymerase to the promoter • eukaryotes have proximal control elements and distal control elements (enhancers) "UPSTREAM" (BEFORE) from the promoter • SPECIFIC TRANSCRIPTION FACTORS: bind to control elements and bring RNA polymerase to a particular gene

✰ EUKARYOTES: REGULATION OF TRANSCRIPTION INITIATION ✰ • eukaryotes do NOT have ________!!! • _________ TRANSCRIPTION FACTORS: bind 1st to promoter then RECRUIT RNA polymerase to the promoter • eukaryotes have proximal control elements and distal control elements (__________) "UPSTREAM" (BEFORE) from the promoter • ________ TRANSCRIPTION FACTORS: bind to control elements and bring RNA polymerase to a particular gene

✰ EUKARYOTIC CHROMATIN ✰ • DNA double helix (2 nm in diameter) is wound TWICE around a PROTEIN CORE of 8 histone molecules → a 10 nm NUCLEOSOME

✰ EVAPORATIVE COOLING ✰ • (ℓ) → (g) (ex: sweating) • Why do we sweat? - when we get too hot, our bodies put H₂O on the surface of our skin - some of the molecules of water will be hotter than the others - when the sun's rays hit the sweat, the HOTTEST MOLECULES will evaporate as gas, leaving cooler molecules behind on your skin and making you feel cooler - overall, the average temperature on your skin has decreased • Evaporation → surface cooling and stable temperatures in our bodies • Why does high humidity on a hot day feel so uncomfortable? - high concentration of water vapor in the air inhibits the evaporation of sweat from the body, so the hot H₂O molecules are going to remain on your skin

✰ EVIDENCE OF NATURAL SELECTION : BIOGEOGRAPHY ✰ • BIOGEOGRAPHY: scientific study of the geographic DISTRIBUTION of species • island speciation (Galápagos Islands) (i.e., Australia has GREATER distribution of marsupials than anywhere else)

✰ EVIDENCE OF NATURAL SELECTION : BIOGEOGRAPHY ✰ • BIOGEOGRAPHY: scientific study of the geographic ___________ of species • island speciation (Galápagos Islands) (i.e., Australia has GREATER distribution of marsupials than anywhere else)

✰ EVIDENCE OF NATURAL SELECTION : DIRECT OBSERVATION ✰ • MRSA (drug resistant bacteria)

✰ EVIDENCE OF NATURAL SELECTION : DIRECT OBSERVATION ✰ ✪ peppered moths during the industrial evolution • BEFORE the Industrial Revolution, most tree trunks were covered in white lichen, allowing prey to more easily spot black moths ↓ white moth population >> black moth population • AFTER the Industrial Revolution, most white tree trunks became coated with black soot, allowing prey to more easily spot the white moths ↓ white moth population << black moth population

✰ EVIDENCE OF NATURAL SELECTION : FOSSIL RECORD ✰ • TRANSITIONAL FORMS link past & present (i.e., the archaeopteryx provides a link between birds & dinosaurs)

✰ EVIDENCE OF NATURAL SELECTION : FOSSIL RECORD ✰ • ___________ FORMS link past & present (i.e., the archaeopteryx provides a link between birds & dinosaurs)

✰ EVIDENCE OF NATURAL SELECTION : FOSSIL RECORD ✰ • fossil formation requires a lot of PRESSURE, and not a lot of scattered pieces

✰ EVIDENCE OF NATURAL SELECTION : FOSSIL RECORD ✰ • ordered sequence

✰ EVIDENCE OF NATURAL SELECTION : COMPARATIVE ANATOMY ✰ • COMPARATIVE ANATOMY: comparison of body structure between different SPECIES • HOMOLOGY: similarity in structures due to COMMON ANCESTRY • HOMOLOGOUS STRUCTURES: similar structures for DIFFERENT functions that indicate a COMMON ANCESTOR

✰ EVIDENCE OF NATURAL SELECTION : HOMOLOGY ✰ • COMPARATIVE ANATOMY: comparison of body structure between different ________ • HOMOLOGY: similarity in structures due to _______________ • HOMOLOGOUS STRUCTURES: similar structures for _________ functions that indicate a COMMON ANCESTOR

✰ EVIDENCE OF NATURAL SELECTION : HOMOLOGY ✰ • VESTIGIAL STRUCTURES - nonfunctional remnants of important features in ancestors (i.e., goosebumps)

✰ EVIDENCE OF NATURAL SELECTION : HOMOLOGY ✰ ✪ COMPARATIVE EMBRYOLOGY • very early stage embryos look VERY SIMILAR, and their differences become more apparent in the late stages (HOMOLOGOUS RELATIONSHIPS)

✰ EVIDENCE OF NATURAL SELECTION : HOMOLOGY ✰ ✪ CONVERGENT EVOLUTION: • process whereby organisms that ARE NOT closely related INDEPENDENTLY evolve SIMILAR ANALOGOUS TRAITS as a result of having to adapt to SIMILAR ENVIRONMENTS • DOES NOT give info about ancestry

✰ EVIDENCE OF NATURAL SELECTION : HOMOLOGY ✰ ✪ CONVERGENT EVOLUTION: • process whereby organisms that ARE NOT closely related INDEPENDENTLY evolve SIMILAR __________ TRAITS as a result of having to adapt to SIMILAR ENVIRONMENTS • DOES NOT give info about ancestry

✰ EVIDENCE OF NATURAL SELECTION : MOLECULAR BIOLOGY ✰ • based on DNA • "COMMON HERITAGE": one was derived from the other

✰ EVIDENCE OF NATURAL SELECTION : MOLECULAR BIOLOGY ✰ • based on _____ • "COMMON HERITAGE": one was derived from the other

✰ EVIDENCE OF NATURAL SELECTION : MOLECULAR BIOLOGY ✰ ✪ LINKING CLASSIFICATION AND PHYLOGENY • PHYLOGENY: represents a hypothesis about EVOLUTIONARY relationships • taxonomy has NOTHING to do with EVOLUTIONARY relationships (instead, it is based on MORPHOLOGY)

✰ EVIDENCE OF NATURAL SELECTION : MOLECULAR BIOLOGY ✰ ✪ LINKING CLASSIFICATION AND PHYLOGENY • PHYLOGENY: represents a hypothesis about ____________ relationships • taxonomy has NOTHING to do with __________ relationships (instead, it is based on ____________)

✰ EVIDENCE OF NATURAL SELECTION : MOLECULAR BIOLOGY ✰ ✪ PHYLOGENETIC TREES • order of taxa at branch tips is NOT important • what matters is the BRANCHING PATTERN, which signifies the order in which the lineages have DIVERGED from common ancestors

✰ EVIDENCE OF NATURAL SELECTION : MOLECULAR BIOLOGY ✰ ✪ PHYLOGENETIC TREES • phylogenetic trees show patterns of descent, NOT PHENOTYPIC similarity • phylogenetic trees do NOT indicate when species EVOLVED or how much change occurred in a lineage • it SHOULD NOT be assumed that a taxon evolved from a taxon next to it

✰ EVIDENCE OF NATURAL SELECTION : MOLECULAR BIOLOGY ✰ ✪ PHYLOGENETIC TREES • phylogenetic trees show patterns of descent, NOT ___________ similarity • phylogenetic trees do NOT indicate when species _________ or how much change occurred in a lineage • it __________ (should/should not) be assumed that a taxon evolved from a taxon next to it

✰ EVOLUTION OF THE GENETIC CODE ✰ • genetic code is NEARLY UNIVERSAL • genes can be moved from one species to another

✰ EVOLUTIONARY SIGNIFICANCE OF ALTERED DNA NUCLEOTIDES ✰ • other mutations can occur outside of replication (i.e., DNA damaged due to physical or chemical agents) ↓ • these mutations may become PERMANENT and be PASSED ON... → genetic variation

genetic variation

✰ EVOLUTIONARY SIGNIFICANCE ✰ • asexual reproduction uses LESS ENERGY, BUT sexual reproduction is nearly universal b/c meiosis INCREASES THE ________ __________ among offspring (4 unique daughter cells)

✰ EXERGONIC REACTIONS ✰ • i.e., cellular respiration • reactants are HIGH energy, products are low energy • -∆G • RELEASES ENERGY TO SYSTEM • CATABOLIC THINK: EXERGONIC: HIGH → low CATABOLIC: COMPLEX → simple

✰ EXTERNAL REGULATION ✰ • GROWTH FACTOR → a protein that STIMULATES other cells to divide • DENSITY-DEPENDENT INHIBITION → phenomenon in which crowded cells stop dividing (i.e., why a scar tissue doesn't just keep growing) • ANCHORAGE DEPENDANCE → in order to divide, cell must be attached to a BASEMENT MEMBRANE ***CANCEROUS CELLS DO 🚫 RESPOND TO THESE NORMAL SIGNALS*** - cancerous cells that 🚫 respond to density-dependent inhibition → tumors - cancerous cells that 🚫 respond to anchorage dependance → metastasis

triglyceride

✰ FATS ✰ • glycerol + 3 fatty acid chains (hydrocarbons) • 1 of 3 dehydration reactions (3 = triglycerides) • Function: energy storage - fats > carbohydrates in terms of energy storage - compact way for 🐖s to carry energy stores - 🌿s DO NOT move, so they can sacrifice the energy given by fats and use carbohydrates instead

✰ FEEDBACK INHIBITION ✰ • mode of METABOLIC CONTROL in which the end product of a reaction acts as a regulator of the reaction by INHIBITING an enzyme from an EARLIER step in the sequence • if there's ENOUGH isoleucine, isoleucine will BIND at the enzyme's active site to prevent STEP 1 (threonine attaching to active site) from reoccurring • as isoleucine binds and unbinds from the enzyme, its total amount is DECREASING • as isoleucine DECREASES, the active site returns to normal, and the pathway continues

✰ FIRST LAW OF THERMODYNAMICS ✰ • energy of universe is CONSTANT... it can be CHANGED or TRANSFERRED, but it CANNOT be CREATED or DESTROYED

✰ FIVE CONDITIONS FOR HARDY-WEINBERG EQUILIBRIUM ✰ 1. 🚫 mutations 2. random mating 3. 🚫 natural selection 4. extremely large population size 5. 🚫 gene flow (🚫 introduction of new genes into population)

✰ FORMS OF ENERGY ✰ • ENERGY: capacity to cause change - kinetic energy (motion) - chemical energy (reaction)

✰ FRAMESHIFT mutation ✰ ✪ a single BASE-PAIR has been DELETED or INSERTED in the coding region of a gene, thus altering the READING FRAME of the resulting mRNA and typically producing a NONFUNCTIONAL polypeptide (due to the significantly altered amino acid sequence) DNA HAS ALL "YOU" CAN ASK FOR ↓ DNA HAS ALY "OUC" ANA SKF OR

✰ FRAMESHIFT mutation ✰ ✪ a single ________ has been DELETED or INSERTED in the coding region of a gene, thus altering the _____________ of the resulting mRNA and typically producing a ____________ polypeptide (due to the significantly altered amino acid sequence) DNA HAS ALL "YOU" CAN ASK FOR ↓ DNA HAS ALY "OUC" ANA SKF OR

✰ FRANKLIN'S X-RAY IMAGES SHOWED THE FOLLOWING: ✰ • DNA was helical • double helix • the width of the helix • the spacing of the bases

✰ FREE-ENERGY & UNSTABLE SYSTEMS ✰ • the LESS free energy there is in a system, the MORE STABLE and MORE FAVORABLE the system is (because the system will be UNLIKELY TO CHANGE)

✰ FREE-ENERGY CHANGE (∆G) OF A REACTION ✰ • FREE ENERGY: portion of a system's energy that can perform work when temperature and pressure are uniform throughout the system, as in a living cell • CHANGE IN FREE ENERGY: (∆G... G is for Gibbs free energy) change in energy when you go from REACTANTS to PRODUCTS ↓ ∆G = ∆H-T∙∆S Energy of universe = change in system's enthalpy - temperature∙change in system's entropy • SPONTANEOUS (-∆G) reactions 🚫 require energy

✰ FREE-ENERGY CHANGE (∆G) OF A REACTION ✰ • ∆G = G(final) - G(initial) • -∆G = spontaneous reaction

✰ For every mRNA strand, its 5'→3' sequence matches, IN RNA BASES, the 5'→3' sequence of the CODING STRAND ✰

✰ GALÁPAGOS FINCHES 🐦 ✰ • different beaks arose through SPECIATION

✰ GALÁPAGOS FINCHES 🐦 ✰ • different beaks arose through __________

✰ GENE FLOW ✰ ✪ transfer of ALLELES from ONE POPULATION TO ANOTHER by the movement of individuals or gametes → REDUCED genetic variation BETWEEN populations over time (WITHIN the population that RECEIVES the immigrants, genetic variation ↑↑) • can increase OR decrease the FITNESS of a population • can lead to gain OR loss of ALLELES

✰ GENE FLOW ✰ ✪ transfer of _________ from ONE POPULATION TO ANOTHER by the movement of individuals or gametes → REDUCED genetic variation BETWEEN populations over time (WITHIN the population that RECEIVES the immigrants, genetic variation ↑↑) • can increase OR decrease the _________ of a population • can lead to gain OR loss of ________

✰ GENETIC DRIFT ✰ ✪ random changes in allele frequencies caused by CHANCE events • FOUNDER EFFECT - when a very small number of individuals from a large population branch off and start their OWN population → REDUCED genetic variation and/or new allele frequencies in the new population • BOTTLENECK EFFECT: - drastic reduction in population size (i.e., disease, starvation, natural disaster) → if the population remains small, genetic drift occurs

✰ GEORGE CUVIER ✰ • paleontologist • explained fossils as CATASTROPHIC EXTINCTION • following this, the area was repopulated with things from other areas

✰ GEORGE CUVIER ✰ • paleontologist • explained fossils as ____________ • following this, the area was repopulated with things from other areas

✰ G₂ OF INTERPHASE ✰ • checking phase • chromosomes 🚫 be seen b/c they have NOT condensed; they're like COILED, MESSY NOODLES

✰ HISTONE MODIFICATIONS ✰ • acetylation (acetyl groups + histone tails) → LOOSER chromatin structure → INCREASED access to DNA → INCREASED transcription • methylation (methyl groups + histone tails) → TIGHTER chromatin structure → DECREASED access to DNA → DECREASED transcription *tip: methylation contains the word "meth," and it leads to a Tighter chromatin structure... connect the "t" in "tight" to Tuco from Breaking Bad

✰ HISTONE MODIFICATIONS ✰ • acetylation (acetyl groups + histone tails) → _________ chromatin structure → INCREASED access to DNA → INCREASED transcription • methylation (methyl groups + histone tails) → _________ chromatin structure → DECREASED access to DNA → DECREASED transcription

✰ HOMOLOGOUS CHROMOSOMES ✰ • for every one of your SOMATIC CELLS (ALL the cells of your body EXCEPT your gametes), you have TWO SETS OF EVERY CHROMOSOME • 23 chromosomes x 2 = 46 • HOMOLOGS are the same size, same shape, and carry genes for the same traits, BUT they are NOT NECESSARILY IDENTICAL (the homologs can carry different ALLELES/VERSIONS of their genes)

✰ HOW ARE GAMETES PRODUCED? ✰ • MEIOSIS helps the cell MAINTAIN CHROMOSOME NUMBER • GAMETES (HAPLOID CELLS) are the ONLY human cell produced by meiosis instead of mitosis

✰ HOW DO NEW SPECIES FORM? ✰ ✪ ALLOPATRIC SPECIATION ( WITH geographic isolation) ✪ SYMPATRIC SPECIATION ( WITHOUT geographic isolation)

✰ HOW DO NEW SPECIES FORM? ✰ ✪ ALLOPATRIC SPECIATION ( ________ geographic isolation) ✪ SYMPATRIC SPECIATION ( ________ geographic isolation)

✰ HOW DOES ATP HYDROLYSIS PERFORM WORK? ✰ • In this example, ATP hydrolysis (exergonic) DRIVES the NON-SPONTANEOUS (endergonic) formation of glutamic acid (ENERGY COUPLING)

✰ HOW ENZYMES SPEED UP REACTIONS ✰ • enzymes REDUCE↓↓ the E(a) in order to SPEED UP the reaction • enzymes do NOT affect the start point or endpoint of the reaction!!!

✰ HOW LINKAGE AFFECTS INHERITANCE ✰ • Thomas Hunt Morgan (known for his fly experiments) struggled to create mutants • unlike Mendel, who repeatedly saw a 3:1 ratio when he bred heterozygotes together, Morgan DID 🚫... he kept seeing SPECIFIC GENETIC COMBINATIONS • as a result, Morgan determined the alleles WERE NOT ASSORTING INDEPENDENTLY... why? ⇩ • Morgan concluded that the genes were ON THE SAME CHROMOSOME, which allowed them to BYPASS independent assortment - BUT, they aren't always on the same chromosome due to CROSSING OVER of portions of homologous chromosomes during PROPHASE I

✰ HOW TO STUDY EVOLUTION ✰ ✪ MICROEVOLUTION - changes at the POPULATION level (changes in allele frequencies in a POPULATION over generations) ✪ MACROEVOLUTION - brand pattern of evolution above the SPECIES level

✰ HOW TO STUDY EVOLUTION ✰ ✪ MICROEVOLUTION - changes at the __________ level (changes in allele frequencies in a __________ over generations) ✪ MACROEVOLUTION - brand pattern of evolution above the _________ level

✰ INDEPENDENT ASSORTMENT OF CHROMOSOMES ✰ • homologous chromosomes orient RANDOMLY at metaphase I • each pair of chromosomes sorts maternal and paternal homologs into daughter cells independently of the other pairs

✰ INHERITANCE OF GENES ✰ • ASEXUAL REPRODUCTION (MITOSIS) - 1 parent cell passes ALL OF ITS GENES to 2 genetically identical offspring WITHOUT the fusion of gametes • SEXUAL REPRODUCTION (MEIOSIS) - 2 parents that each donate HALF of their DNA to produce 1 offspring (in other words, you're going from DIPLOID to HAPLOID cells) - the MAIN GOAL of meiosis is to produce HAPLOID GAMETES for SEXUAL REPRODUCTION

✰ INITIATION OF TRANSLATION ✰ • regulatory PROTEINS can AID in translation by helping the mRNA find the RIBOSOME or HINDER translation by attaching at the 5' CAP or the POLY-A TAIL to prevent the attachment of ribosomes • all mRNAs in a cell may be regulated SIMULTANEOUSLY (i.e., massive translation ACTIVATION in a(n) EGG following fertilization) or they may be regulated individually

✰ INITIATION OF TRANSLATION ✰ • regulatory ________ can AID in translation by helping the mRNA find the _________ or HINDER translation by attaching at the ________ or the _________ to prevent the attachment of ribosomes • all mRNAs in a cell may be regulated ___________ (i.e., massive translation ________ in a(n) ______ following fertilization) or they may be regulated individually

✰ INTERPHASE ✰ • diploid cell duplicates its chromosomes to produce sister chromatids

✰ INVERSION ✰ • occurs when a segment is REVERSED

✰ IONIC BONDS ✰ • in some cases, 2 atoms are so unequal in their attraction for VE's that the more electronegative atom STRIPS an electron completely away from its partner • the resulting oppositely charged atoms are called IONS • b/c of their opposite charges, cations and anions attract each other in an IONIC BOND

✰ JEAN-BAPTISTE DE LAMARCK'S HYPOTHESIS OF CHANGE (early 1800's) ✰ • 1st to explain HOW life changes over time → evolution!!! • compared living species with FOSSILS • said species evolve by: - USE AND DISUSE of body parts - inheritance of ACQUIRED CHARACTERISTICS • i.e., giraffes

✰ JEAN-BAPTISTE DE LAMARCK'S HYPOTHESIS OF CHANGE (early 1800's) ✰ • 1st to explain HOW life changes over time → evolution!!! • compared living species with ______ • said species evolve by: - ___________ of body parts - inheritance of _____________ • i.e., giraffes

✰ KARYOTYPE ✰ • KARYOTYPE → diagram of homologous chromosome pairs • AUTOSOMES → any chromosome that is NOT a sex chromosome (X or Y)

Summary: The operon will be switched on due to high levels of lactose (and thus high levels of allolactose), but since CAP will NOT bind to the CAP binding site, transcription will be SLOW

✰ LAC OPERON EXPRESSION ✰ • HIGH glucose + HIGH lactose → ↓ transcription - HIGH glucose → LOW cAMP → INACTIVE CAP → SLOWER transcription - HIGH lactose → HIGH allolactose → INACTIVE lacI → UNBOUND lac repressor → ON operon

Summary: CAP will NOT bind to the CAP binding site, but because there are low levels of lactose (and thus low levels of allolactose), the lac repressor will bind to the operator and BLOCK RNA polymerase from even BEGINNING transcription

✰ LAC OPERON EXPRESSION ✰ • HIGH glucose + LOW lactose → 🚫 transcription - HIGH glucose → LOW cAMP → INACTIVE CAP → DECREASED transcription - LOW lactose → LOW allolactose → ACTIVE lacI → BOUND lac repressor → OFF operon

Summary: CAP will bind to the CAP binding site, and high levels of lactose (and thus high levels of allolactose) will INACTIVATE the lac repressor and switch the operon on, INCREASING transcription

✰ LAC OPERON EXPRESSION ✰ • LOW glucose + HIGH lactose → ↑ transcription - LOW glucose → HIGH cAMP → ACTIVE CAP → INCREASED transcription - HIGH lactose → HIGH allolactose → INACTIVE lacI → UNBOUND lac repressor → ON operon

Summary: CAP will be bound to the CAP binding site, ready to drive higher levels of transcription, but due to low levels of lactose, the lac repressor will bind to the operator and BLOCK RNA polymerase from even BEGINNING transcription

✰ LAC OPERON EXPRESSION ✰ • LOW glucose + LOW lactose → 🚫 transcription - LOW glucose → HIGH cAMP → ACTIVE CAP → CAP binds to CAP binding site - LOW lactose → LOW allolactose → ACTIVE lacI → BOUND lac repressor → OFF operon

✰ LACTIC ACID FERMENTATION ✰ • NADH reduces the 2 pyruvates from glycolysis to form LACTIC ACID and REGENERATE NAD⁺ so that glycolysis can continue • your muscles burn when you exercise really hard because your muscles are USING UP OXYGEN TOO QUICKLY, so your cells reduce pyruvate to LACTIC ACID to REGENERATE NAD⁺ and allow cellular respiration to continue

✰ LACTOSE OPERON OFF ✰ ABSENT lactose ↓ Allolactose DOES NOT BIND to the lac repressor protein ↓ ACTIVE lac repressor protein DOES ATTACH to the OPERATOR ↓ OFF operon ↓ RNA polymerase DOES NOT attach to the operon's PROMOTER ↓ RNA polymerase DOES NOT TRANSCRIBE the operon's genes

✰ LACTOSE OPERON OFF ✰ ABSENT lactose ↓ Allolactose ________ to the lac repressor protein ↓ _______ lac repressor protein ___________ to the OPERATOR ↓ ____ operon ↓ RNA polymerase __________ attach to the operon's PROMOTER ↓ RNA polymerase ___________ the operon's genes

✰ LACTOSE OPERON ON ✰ PRESENT lactose ↓ Allolactose DOES BIND to the lac repressor protein ↓ INACTIVE lac repressor protein DOES NOT ATTACH to the OPERATOR ↓ ON operon ↓ RNA polymerase DOES ATTACH to the operon's PROMOTER ↓ RNA polymerase DOES TRANSCRIBE the operon's genes

✰ LACTOSE OPERON ON ✰ PRESENT lactose ↓ Allolactose _________ to the lac repressor protein ↓ ________ lac repressor protein _________ to the OPERATOR ↓ ___ operon ↓ RNA polymerase ________ to the operon's PROMOTER ↓ RNA polymerase __________ the operon's genes

✰ LEAF ANATOMY ✰ • STOMATA: entry site for CO₂ and exit site for O₂ (GAS EXCHANGE); faces AWAY from 🌞 • CHLOROPLASTS: found in the MESOPHYLL • ∼30-40 chloroplasts per cell • the part FACING the 🌞 can be WAXY

✰ LIGHT REACTIONS ✰ • WHERE? → thylakoids • FUNCTION? → convert solar energy to ATP and NADPH STEPS: 1) a photon strikes a molecule of chlorophyll 2) H₂O SPLITS into O₂ to replace the excited electrons that boost up 2) an excited electron is boosted ↑ to a HIGHER ENERGY LEVEL 3) as this electron falls back ↓, ANOTHER electron is raised to an excited state 4) the process continues until the relayed energy reaches the P680 pair of chlorophyll a molecules in the PSII reaction-center complex 5) electron goes from P680 → primary electron acceptor 6) electron passes through ELECTRON TRANSPORT CHAIN, moving DOWN to a LOWER ENERGY LEVEL as it moves 7) as the electron moves ↓ the chain from PSII to the cytochrome complex, the energy being RELEASED powers the PUMPING of H⁺ ions from the STROMA (low H⁺ concentration) into the THYLAKOID SPACE (high H⁺ concentration) - H⁺ ions then diffuse BACK ACROSS THE MEMBRANE into the stroma (empty space) by moving through ATP synthase, which powers the production of ATP 9) in the reaction center of PSI, the electron is now at a LOWER energy level, so it must now get hit by ANOTHER photon 11) middle chlorophyll moves excited electron to HIGHER level 12) excited electron is now passed through a SECOND ELECTRON TRANSPORT CHAIN through ferredoxine protein 13) the enzyme "NADP⁺ reductase" REDUCES NADP⁺→NADPH

✰ LIPIDS ✰ • HYDROPHOBIC (unifying feature!!!) (mix poorly with water) HYDROCARBONS • nonpolar • 3 types: - fats - phospholipids - steroids • fats separate in water - b/c the water molecules hydrogen-bond to each other and exclude the fats

✰ MACROMOLECULES ✰ • CRITICALLY important molecule of ALL LIVING THINGS - carbohydrates - nucleic acids - proteins - lipids

✰ MAPPING THE DISTANCE BETWEEN GENES ✰ • LINKAGE MAP: ordered list of the genetic loci along a particular chromosome • RECOMBINATION FREQUENCY: how likely it is that CROSSING OVER will split chromosomes apart; the percentage of testcross progeny that are recombinants - the FARTHER apart 2 genes are on a chromosome, the HIGHER the probability that a crossover will occur (the HIGHER the recombination frequency) • genes FAR apart → recombination frequency near 50% • genes FAR apart on a chromosome are PHYSICALLY LINKED (b/c they're on the same chromosome), but GENETICALLY UNLINKED (b/c crossing over can switch them)

✰ MEIOSIS I ✰ • **homologous chromosomes SEPARATE** → haploid cells with duplicated chromosomes

✰ MEIOSIS II ✰ • **sister chromatids SEPARATE** • EACH HAPLOID CELL DIVIDES into TWO MORE HAPLOID CELLS that EACH contain one unduplicated chromosome

✰ MEIOSIS ✰ • TWO cell divisions - Meiosis I (92 → 46 chromosomes) - Meiosis II (46 → 23 chromosomes) • FOUR haploid daughter cells - Meiosis I (1→2 cells) - Meiosis II (2→4 cells) • MEIOSIS is production of egg & sperm and UP TO fertilization • zygote → DIPLOID

✰ MEIOSIS: FINAL REVIEW ✰ • 4 daughter cells • HAPLOID number of chromosomes • EACH daughter cell is unique from the others AND from the ORIGINAL parent cells

✰ MENDEL'S MODEL: CONCEPT 1 ✰ 1) Alternative VERSIONS of genes account for variations in inherited characters - basically, the gene for flower color existed in TWO versions (one for purple flowers and the other for white flowers) • these "versions" are called ALLELES

✰ MENDEL'S MODEL: CONCEPT 2 ✰ 2) An organism inherits ONE ALLELE from EACH PARENT for EACH TRAIT (GENE) • the 2 alleles at a particular locus are either: - the SAME (P gen) - DIFFERENT (F₁ gen)

✰ MENDEL'S MODEL: CONCEPT 3 ✰ 3) If the 2 alleles at a particular locus DIFFER, then the DOMINANT allele determines appearance

✰ MENDEL'S MODEL: CONCEPT 4 ✰ 4) The 2 alleles for a heritable character SEGREGATE during GAMETE FORMATION and end up in SEPARATE gametes • basically, per EACH gene, EACH gamete (haploid) receives ONLY ONE of its TWO alleles (it will 🚫 have BOTH!!!!)

✰ MENDEL'S PEA EXPERIMENT ✰ • P GENERATION: Mendel cross-pollinated two different TRUE-BREEDING varieties (HYBRIDIZATION) • F₁ GENERATION: all F₁ offspring were PURPLE... what happened to the white trait? • F₂ GENERATION: 3:1 ratio of purple:white offspring 🔑: the "heritable factor" for white flowers was MASKED, 🚫 diluted or destroyed

✰ METABOLISM ✰ • METABOLISM is all of an organism's CHEMICAL REACTIONS • we can picture metabolism as an elaborate road map of METABOLIC PATHWAYS (not just a single step) - EACH STEP is catalyzed by specific enzyme

✰ METAPHASE I ✰ • kinetochore microtubules attach to TETRADS & pull them to metaphase plate

✰ METAPHASE II ✰ • kinetochore microtubules pull sister chromatids to metaphase plate • due to CROSSING OVER of sister chromatids during PROPHASE I, the two sister chromatids of each chromosome are 🚫 genetically identical

✰ METAPHASE ✰ • shortening and lengthening microtubules pull chromosomes to middle of cell (METAPHASE PLATE)

✰ MICRORNA's (miRNA's) ✰ • small, single stranded RNA molecules that bind to complementary mRNA sequences in the UTR • DEGRADE the mRNA or block its translation • may be within INTRONS

✰ MICRORNA's (miRNA's) ✰ • small, single stranded RNA molecules that bind to complementary ______ sequences in the ____ • __________ the mRNA or block its translation • may be within ______

✰ MISMATCH REPAIR DURING G2 ✰ • checking prior to M phase • MISMATCH REPAIR - instead of DNA polymerase, OTHER ENZYMES remove and replace incorrectly paired nucleotides - chemical or physical agents (i.e., cigarette smoke, X-rays) - spontaneous changes

✰ MISSENSE mutation ✰ ✪ a SENSE CODON is changed to a DIFFERENT SENSE CODON that specifies a DIFFERENT AMINO ACID, thus POTENTIALLY changing the FUNCTION of the polypeptide DNA HAS ALL "YOU" CAN ASK FOR ↓ DNA HAS ALL "LOU" CAN ASK FOR

✰ MISSENSE mutation ✰ ✪ a __________ is changed to a DIFFERENT ________ that specifies a DIFFERENT _________, thus POTENTIALLY changing the _______ of the polypeptide DNA HAS ALL "YOU" CAN ASK FOR ↓ DNA HAS ALL "LOU" CAN ASK FOR

✰ MITOSIS IN EUKARYOTES ✰ • MITOSIS (ASEXUAL REPRODUCTION) → produces daughter nuclei that are EXACT GENETIC COPIES of the parental nucleus • in eukaryotic cells, the cell cycle is divided into TWO MAJOR PHASES 1) INTERPHASE (90% OF CELL'S LIFE) a. G₁ (cellular growth) b. S (DNA replication) c. G₂ (checking phase) * (G₀ - where cell goes if it decides not to divide or if there's been an error) 2) M PHASE (10% OF CELL'S LIFE) a. mitosis (DUPLICATED CHROMOSOMES divide) b. cytokinesis (the CELL divides)

✰ MOLECULES WITH CARBON ✰ • carbon can form 4 covalent bonds (b/c it needs 4 VE's to fill its shell) - as a result, carbon can form MANY large complex molecules • Most frequent partners: - hydrogen - oxygen - nitrogen - carbon

✰ MULTIPLE POLYPEPTIDES ✰ • a single mRNA strand can used to make MULTIPLE polypeptides simultaneously

✰ MUTAGENS ✰ • spontaneous mutations can occur during DNA REPLICATION, RECOMBINATION, or REPAIR • AMES TEST: tests for any product you put on your skin for mutagenic activity of chemicals • 🚫 all mutations are bad, they can lead to variation

✰ MUTAGENS ✰ • spontaneous mutations can occur during DNA _________, __________, or ________ • AMES TEST: tests for any product you put on your skin for mutagenic activity of chemicals • 🚫 all mutations are bad, they can lead to variation

✰ NATURAL SELECTION ✰ ✪ evolutionary process by which ALLELES that increase the likelihood of survival and the reproductive output of the individuals that carry them become more common in subsequent generations ✪ is the ONLY mechanism that CONSISTENTLY causes ADAPTIVE EVOLUTION • involves both chance (mutations) AND sorting (of beneficial alleles, which are favored) • operates on "BETTER THAN" basis

✰ NATURAL SELECTION ✰ ✪ evolutionary process by which ________ that increase the likelihood of survival and the reproductive output of the individuals that carry them become more common in subsequent generations ✪ is the ONLY mechanism that CONSISTENTLY causes _____________ • involves both chance (mutations) AND sorting (of beneficial alleles, which are favored) • operates on __________ basis

✰ NONCODING RNA's ✰ • for each DNA gene, many INTRONS are removed • each cell contains 6 ft of DNA but only 20,000 genes • ONLY 2% of DNA encodes proteins in order to CONSERVE ENERGY

✰ NONCODING RNA's ✰ • for each DNA gene, many ______ are removed • each cell contains 6 ft of DNA but only 20,000 genes • ONLY 2% of DNA encodes proteins in order to _______________

✰ NONCODING RNA's ✰ • what else is there in DNA? - genes for RNA splicing - genes for RNA that stay as RNA (that is, they DO NOT make PROTEINS) such as rRNA or tRNA (which are therefore NOT included in the 2% of DNA that encodes proteins) - millions of transcription factors - noncoding RNA's ↓ • their purpose is REGULATION

✰ NONCODING RNA's ✰ • what else is there in DNA? - genes for _______ splicing - genes for RNA that STAY as RNA (that is, they DO NOT make _________) such as _____ or tRNA (which are therefore NOT included in the 2% of DNA that encodes proteins) - millions of transcription factors - noncoding _____ ↓ • their purpose is ___________

✰ NONSENSE mutation ✰ ✪ a SENSE codon is changed to a STOP codon DNA HAS ALL "YOU" CAN ASK FOR ↓ DNA HAS ALL "YOU" 🚫

✰ NONSENSE mutation ✰ ✪ a ______ codon is changed to a ______ codon DNA HAS ALL "YOU" CAN ASK FOR ↓ DNA HAS ALL "YOU" 🚫

✰ NUCLEOTIDES ✰ • a NUCLEOTIDE is composed of: - a phosphate group - a 5-carbon sugar - a nitrogenous base • NUCLEOTIDES are the MONOMERS of DNA (the POLYNUCLEOTIDE) • DNA NUCLEOTIDE: - bases: ATCG - sugar: deoxyribose • RNA NUCLEOTIDE: - bases: AUCG - sugar: ribose

✰ OFFSPRING COMBINATIONS AND INDEPENDENT ASSORTMENT ✰ • due to INDEPENDENT ASSORTMENT of chromosomes during MEIOSIS, parents can produce RECOMBINANT OFFSPRING that DO 🚫 resemble them

✰ OPERONS ✰ • INDUCIBLE ENZYMES: enzymes of the CATABOLIC LACTOSE pathway; enzyme synthesis is induced by chemical signals (i.e., metabolism of food) • REPRESSIBLE ENZYMES: enzymes of the ANABOLIC TRYPTOPHAN pathway; enzyme synthesis is repressed by high levels of product

✰ OPERONS ✰ • INDUCIBLE ENZYMES: enzymes of the CATABOLIC ______ pathway; enzyme synthesis is induced by chemical signals (i.e., metabolism of food) • REPRESSIBLE ENZYMES: enzymes of the ANABOLIC ______ pathway; enzyme synthesis is repressed by high levels of product

✰ ORIGINS OF GENETIC VARIATION ✰ • Three mechanisms contribute to GENETIC VARIATION: - crossing over - independent assortment of chromosomes - random fertilization

✰ OTHER DEFINITIONS OF SPECIES ✰ ✪ MORPHOLOGICAL SPECIES CONCEPT: defines a species by STRUCTURAL features ✪ ECOLOGICAL SPECIES CONCEPT: views a species in terms of its ECOLOGICAL NICHE

✰ OTHER DEFINITIONS OF SPECIES ✰ ✪ MORPHOLOGICAL SPECIES CONCEPT: defines a species by ___________ features ✪ ECOLOGICAL SPECIES CONCEPT: views a species in terms of its ____________

✰ OVERVIEW ✰

✰ OVERWHELMING AMOUNT OF SCIENTIFIC EVIDENCE FOR NATURAL SELECTION ✰ 1. Direct observation 2. The fossil record 3. Biogeography 4. Homology 5. Molecular biology

✰ OXIDATION OF GLUCOSE (ORGANIC FUEL) ✰ • the organic fuel that is oxidized in cellular respiration is GLUCOSE (C₆H₁₂O₆, simple monosaccharide)

✰ PHOTOSYNTHETIC PIGMENTS ✰ • PHOTONS (packets of light energy) are absorbed by PIGMENTS • PIGMENTS: different pigments absorb different wavelengths of light - chlorophyll absorbs all colors EXCEPT GREEN - carotenoids absorb all colors EXCEPT ORANGE • electrons go ↑ to HIGHER ORBITAL, & 🌿 uses the energy RELEASED when the electron comes back down

✰ POLYGENIC INHERITANCE ✰ • multiple genes involved (i.e., skin color)

✰ POLYMERS ✰ • Carbohydrates, proteins, & nucleic acids are made of MONOMERS (lipids are NOT) • repeating chains of monomers form polymers • Cells make & break ↓ polymers by same processes: - dehydration synthesis reaction - hydrolysis reaction

✰ POSITIVE GENE REGULATION ✰ • CATABOLITE ACTIVATOR PROTEIN (CAP): - WHAT IS IT? → transcription activator - WHERE? → binds to a region (CAP binding site) of DNA just before the LAC operon's promoter - FUNCTION(S)? → helps RNA polymerase attach to the PROMOTER and drive HIGHER levels of transcription - HOW DOES IT WORK? → when glucose levels are LOW, cAMP (cyclic AMP) levels are HIGH, and cAMP then allows CAP to bind to the LAC operon and SPEED UP transcription

✰ POSITIVE GENE REGULATION ✰ • CATABOLITE ACTIVATOR PROTEIN (CAP): - WHAT IS IT? → transcription activator - WHERE? → binds to a region (CAP binding site) of DNA just before the ___ operon's promoter - FUNCTION(S)? → helps RNA polymerase attach to the ________ and drive HIGHER levels of transcription - HOW DOES IT WORK? → when glucose levels are LOW, cAMP (cyclic AMP) levels are HIGH, and cAMP then allows CAP to bind to the ___ operon

✰ POSITIVE GENE REGULATION ✰ • E. coli will preferentially use GLUCOSE to save energy

✰ POSITIVE GENE REGULATION ✰ • E. coli will preferentially use _______ to save energy

✰ POST-TRANSCRIPTIONAL CONTROL: PROTEIN DEGRADATION ✰ • SELECTIVE DEGRADATION: the length of time each protein functions • UBIQUITIN: - found in EUKARYOTIC cells - F: attaches to a PROTEIN and signals cell to degrade it via PROTEASOME

✰ POST-TRANSCRIPTIONAL CONTROL: PROTEIN DEGRADATION ✰ • SELECTIVE DEGRADATION: the length of time each protein functions • ___________: - found in __________ cells - F: attaches to a _________ and signals cell to degrade it via __________

✰ POST-TRANSCRIPTIONAL CONTROL: PROTEIN PROCESSING ✰ • CLEAVAGE events (i.e, insulin) • chemical MODIFICATION (i.e., phosphorylation of regulatory proteins)

✰ POST-TRANSCRIPTIONAL CONTROL: PROTEIN PROCESSING ✰ • ________ events (i.e, insulin) • chemical ___________ (i.e., phosphorylation of regulatory proteins)

✰ POST-TRANSCRIPTIONAL REGULATION ✰ • includes RNA processing, mRNA degradation, translation, and protein processing and degradation • post-transcriptional regulation allows a cell to make sure that a PROTEIN is FUNCTIONAL • allows for RAPID fine-tuning of gene expression in response to ENVIRONMENTAL changes • NOT EVERY PROTEIN goes through post-transcriptional regulation

✰ POST-TRANSCRIPTIONAL REGULATION ✰ • includes RNA processing, mRNA degradation, translation, and protein processing and degradation • post-transcriptional regulation allows a cell to make sure that a ________ is FUNCTIONAL • allows for RAPID fine-tuning of gene expression in response to _________ changes • NOT EVERY PROTEIN goes through post-transcriptional regulation

✰ POSTZYGOTIC BARRIERS ✰ 1. Reduced hybrid variability 2. Reduced hybrid fertility 3. Hybrid breakdown

✰ PREZYGOTIC BARRIERS ✰ 1. Temporal isolation 2. Habitat isolation 3. Behavioral isolation 4. Mechanical isolation 5. Gamete isolation

✰ PROKARYOTES (BACTERIA) ✰ • Why do PROKARYOTES go through differential gene expression? - energy conservation - efficiency - favored by natural selection ✪ OPERONS - a cluster of PROKARYOTIC genes regulated by the same PROMOTER

✰ PROKARYOTES (BACTERIA) ✰ • Why do PROKARYOTES go through differential gene expression? - energy conservation - efficiency - favored by natural selection ✪ __________ - a cluster of PROKARYOTIC genes regulated by the same _________

✰ PROMETAPHASE ✰ • microtubules of the growing mitotic spindle ATTACH TO KINETOCHORES in the centromeres of the chromosomes • nuclear envelope COMPLETELY dissolves • chromosomes are now COMPLETELY CONDENSED

✰ PROOFREADING AND REPAIRING DNA ✰ • DURING proofreading, there is a pairing error approx. every 1 in 10⁵ nucleotides • AFTER proofreading, in the completed DNA molecule, there is an error approx. every 1 in 10¹⁰ nucleotides • during DNA replication, many polymerases PROOFREAD complementary nucleotides IMMEDIATELY after they are laid down • if a newly added nucleotide is mismatched, the DNA polymerase REVERSES, using a 3'→5' built-in EXONUCLEASE ACTIVITY to remove the incorrect nucleotide

✰ PROPHASE (1ST STEP OF M-PHASE) ✰ • chromosomes BEGIN TO CONDENSE & become more DISTINCT • mitotic spindle and kinetochore microtubules begin to form • nuclear envelope begins dissolving

✰ PROPHASE I ✰ • CROSSING OVER!!!! • 90% of time in meiosis • chromosomes condense • homologous chromosomes pair up

✰ PROPHASE II ✰ • spindle apparatus reforms • 🚫 crossing over b/c homologous chromosomes NO LONGER EXIST • chromosomes condense

✰ PURINES VS PYRIMADINES ✰ • PAIRING A PURINE WITH A PYRIMIDINE is the ONLY combination that results in a uniform diameter for a double helix • purines are lArGer (adenine & guanine) than pyrimidines • the pyrimidines are thymine, cytosine, & uracil

✰ RANDOM FERTILIZATION ✰ • ANY SPERM can fused with ANY unfertilized egg

✰ REACTION CENTER COMPLEX ✰ • when a photon strikes a pigment molecule in a light-harvesting complex, the energy is PASSED (like a hot potato) from molecule to molecule until it reaches the REACTION CENTER COMPLEX • the CENTER chlorophyll that ACTUALLY goes through reactions

✰ READING FRAME ✰ • codons must be read in the correct READING FRAME (the correct groupings of 3... they CAN'T overlap) • AUG sets the reading frame

✰ RECESSIVELY INHERITED DISORDERS ✰ • i.e., albinoism, sickle cell anemia, cystic fibrosis • seen ONLY in individuals HOMOZYGOUS for the allele • heterozygous parents are CARRIERS

✰ REDOX REACTIONS ✰ • oxidation: loss of e⁻, loss of H⁺, loss of energy • reduction: gain of e⁻, gain of H⁺, gain of e⁻

✰ REGULATION OF CHROMATIN STRUCTURE ✰ • the structural organization of CHROMATIN helps regulation gene expression - HETEROCHROMATIN: TIGHTLY packed chromatin → DNA inside IS NOT expressed - EUCHROMATIN: LOOSELY packed chromatin → DNA inside IS expressed • histone proteins & nucleosomes *Summary: more open or "relaxed" chromatin makes a gene more available for transcription *tip: the "oo" sound in EUchromatin sounds like the "oo" sound in the word "lOOse"

✰ REGULATION OF CHROMATIN STRUCTURE ✰ • the structural organization of _________ helps regulation gene expression - HETEROCHROMATIN: _________ packed chromatin → DNA inside IS NOT expressed - EUCHROMATIN: _________ packed chromatin → DNA inside IS expressed • histone proteins & nucleosomes

✰ REGULATION OF GENE EXPRESSION ✰ • TRYPTOPHAN is an AMINO ACID used in the synthesis of PROTEINS • in the pathway for tryptophan synthesis, an ABUNDANCE of tryptophan can INHIBIT the expression of certain GENES that make the enzymes in the pathway (FEEDBACK INHIBITION) ABUNDANCE OF TRYPTOPHAN → INHIBITION OF GENE EXPRESSION

✰ REGULATION OF GENE EXPRESSION ✰ • TRYPTOPHAN is an AMINO ACID used in the synthesis of __________ • in the pathway for tryptophan synthesis, an ___________ of tryptophan can INHIBIT the expression of certain _______ that make the enzymes in the pathway (this is known as _____________) ___________ OF TRYPTOPHAN → INHIBITION OF GENE EXPRESSION

✰ REGULATION OF METABOLISM ✰

✰ RELATIVE FITNESS ✰ • the contribution an individual makes to the GENE POOL of the next generation relative to the contributions of other individuals • how natural selection determines who LIVES and who DIES

✰ RELATIVE FITNESS ✰ • the contribution an individual makes to the __________ of the next generation relative to the contributions of other individuals • how natural selection determines who LIVES and who DIES

✰ REPLICATION IN EUKARYOTIC CELL ✰ • eukaryotic cells have MANY MORE origins of replication than a bacterial cell

✰ REPLICATION IN PROKARYOTES (20-40 minutes) ✰

✰ RIBOSOMES ✰

✰ RNA PROCESSING: ALTERATION OF mRNA ENDS ✰ • in eukaryotic cells, after a DNA template is transcribed into a pre-mRNA molecule, each end of the pre-mRNA molecule is modified in the following ways: 1. the 5' end receives a 5' cap (guanine-containing nucleotide) 2. the 3' end gets a poly-A tail • POLYADENYLATION SIGNAL: specifies where the poly-A tail should be added on the mRNA near the 3' end

✰ RNA PROCESSING: SPLIT GENES AND RNA SPLICING ✰ • more than HALF of pre-mRNA must be removed • INTRONS are REMOVED during RNA splicing b/c they DO NOT code for protein sequences • the remaining EXONS (which DO CODE for protein sequences) at the two ends of the mRNA also contain the 5' UTR (untranslated region) and 3' UTR sequences - as its name implies, the UTR's will NOT be translated into proteins

✰ RNA PROCESSING: ALTERNATIVE RNA SPLICING ✰ • a type of eukaryotic gene regulation at the RNA-PROCESSING level in which different mRNA molecules are produced from the same primary TRANSCRIPT, depending on which RNA segments are treated as exons and which segments are treated as introns ↓ THE RESULT ↓ • changing the function of the protein without changing the DNA ↓ a gene that can code for multiple PROTEINS

✰ RNA-PROCESSING: ALTERNATIVE RNA SPLICING ✰ • a type of eukaryotic gene regulation at the ___________ level in which different mRNA molecules are produced from the same primary _________, depending on which RNA segments are treated as exons and which segments are treated as introns ↓ THE RESULT ↓ • changing the function of the protein without changing the DNA ↓ a gene that can code for multiple ________

✰ RUBISCO & PHOTORESPIRATION ✰ • rubisco is the 1st enzyme involved in the Calvin cycle • Calvin cycle attaches an inorganic CO₂ to RUBISCO (5-carbon sugar) to form 2 molecules of 3-PGA • rubisco binds to both CO₂ & O₂ • after a plant closes its stomata, as the calvin cycle progresses, the amount of CO₂ ↓ while O₂ ↑ • if rubisco attaches to concentrated O₂, the plant will release CO₂ INSTEAD OF ATP & organic sugars... therefore, photorespiration is a WASTE OF ENERGY

✰ SECOND LAW OF THERMODYNAMICS ✰ • during energy transfer, some energy is LOST as 🔥 (HEAT) • every energy transfer increases the ENTROPY (DISORDER) of the universe • ENTROPY: - the universe STRIVES TOWARD DISORDER - entropy makes it harder to build complex macromolecules

✰ SEMI-CONSERVATIVE REPLICATION ✰ • one PARENT strand is partially conserved and one new DAUGHTER strand is added • hydrogen bonds between bases are BROKEN

✰ SETS OF CHROMOSOMES IN HUMAN CELLS ✰ • DIPLOID (2n) → any cell with TWO chromosome sets • HAPLOID (n) → any cell with ONE chromosome set

✰ SEX-LINKED GENES ✰ • Y-linked genes • X-linked genes • X chromosomes have traits UNRELATED to sex

✰ SILENT mutation ✰ ✪ a sense codon is changed to a different sense codon, but the new codon specifies the SAME AMINO ACID, thus leaving the function of the polypeptide UNCHANGED DNA HAS ALL "YOU" CAN ASK FOR ↓ DNA HAS ALL "YOO" CAN ASK FOR

✰ SILENT mutation ✰ ✪ a sense codon is changed to a different sense codon, but the new codon specifies the SAME ________, thus leaving the function of the polypeptide _________ DNA HAS ALL "YOU" CAN ASK FOR ↓ DNA HAS ALL "YOO" CAN ASK FOR

✰ SOURCES OF GENETIC VARIATION ✰ • evolution depends on GENETIC VARIATION (WITHOUT it, organisms go EXTINCT) • % of heterozygous loci (how many alleles are in the population?)

✰ SOURCES OF GENETIC VARIATION ✰ • evolution depends on _____________ (WITHOUT it, organisms go EXTINCT) • % of heterozygous loci (how many alleles are in the population?)

✰ SOURCES OF GENETIC VARIATION ✰ ✪ MOST GENETIC VARIATION COMES FROM ALLELE RECOMBINATION • 3 mechanisms: crossing over, independent assortment, random fertilization (which sperm finds which egg?)

✰ SOURCES OF GENETIC VARIATION ✰ ✪ MUTATIONS • Gene duplication: duplicated genes → new ________ by further mutations (that is, while the first copy does not change b/c its function is VERY IMPORTANT, the second copy can be VERY different) (i.e., odor-detecting genes)

✰ SOURCES OF GENETIC VARIATION ✰ ✪ SELECTION • for FAVORABLE traits • against DELETERIOUS (BAD) traits

✰ SOURCES OF GENETIC VARIATION ✰ ✪ SELECTION • for __________ traits • against ________ traits

✰ SPECIES ✰ • according to the BIOLOGICAL SPECIES CONCEPT, a SPECIES is a group of populations whose members HAVE THE POTENTIAL to INTERBREED and produce VIABLE, FERTILE offspring

✰ SPECIES ✰ • according to the BIOLOGICAL SPECIES CONCEPT, a SPECIES is a group of populations whose members HAVE THE POTENTIAL to __________ and produce VIABLE, _______ offspring

✰ SPLICEOSOMES ✰ • SPLICESOME: complex of proteins and snRNPs ("snurps") - FUNCTION: CLEAVES the pre-mRNA to excise introns, and JOINS the remaining exons

✰ STAGES OF CELLULAR RESPIRATION ✰ • 1. Glycolysis 2a. Pyruvate oxidation 2b. Citric acid cycle 3a. Oxidative phosphorylation 3b. Chemiosmosis • for EACH molecule of glucose, the cell makes approx. 32 ATP - "approx." b/c some is lost as heat

✰ STEPWISE ENERGY HARVEST & THE PURPOSE OF THE ELECTRON TRANSPORT CHAIN✰ • the purpose of the ELECTRON TRANSPORT CHAIN is to release energy in small, manageable steps to decrease the amount of energy that is lost to heat

✰ STRONG ACIDS & BASES ✰ • a STRONG acid/base dissociates COMPLETELY in water

✰ SYMPATRIC SPECIATION ✰ • sympatric = same homeland • occurs between populations that live in the same geographic area • although there are 🚫 physical barriers, sympatric speciation can occur if __________ is reduced by - polyploidy (🌿) - sexual selection - habitat differentiation

✰ TARGETING THE POLYPEPTIDES TO SPECIFIC LOCATIONS ✰ • in a eukaryotic cell, EVERY PROTEIN must be sorted to the compartment where it performs a necessary function • polypeptides that sort to the ENDOMEMBRANE SYSTEM begin their synthesis on FREE RIBOSOMES in the CYTOSOL • SIGNAL SEQUENCE: marks the polypeptides of proteins destined for the endomembrane system or for secretion • FREE RIBOSOMES synthesize proteins that function in the CYTOSOL • BOUND RIBOSOMES synthesize proteins that function in ORGANELLES or that must be SECRETED

✰ TELOMERES ✰ • a eukaryote is a LINEAR molecule • the RNA primer synthesized in DNA replication produces a PROBLEM for replicating the LINEAR CHROMOSOMES of eukaryotes ↓ • the PROBLEM is that after getting rid of the RNA primer, DNA must be added to fill in the gap, BUT there is NO 3' end available for nucleotide addition • as a result, repeated rounds of replication → SHORTER and SHORTER daughter molecules... this can have LETHAL consequences for a cell due to GENE DELETION ↓ • the SOLUTION is TELOMERES!!! • TELOMERES: - NONCODING DNA SEQUENCE located @ the end of linear DNA molecules - takes place on genes that could potentially be deleted as the DNA shortens • an AGING cell is LOSING its TELOMERES... it's getting SHORTER and SHORTER... → eventually, this leads to APOPTOSIS (cell death) • TELOMERASE: - stops the shortening of telomeres by adding telomere repeats to the chromosome ends - active in STEM CELLS - TURNS OFF when cell becomes functional (i.e., when stem cell → lung cell)

✰ TELOMERES: CANCER CELLS ✰ • cancer cells REACTIVATE telomerase → cells that divide INDEFINITELY and DON'T DIE

✰ TELOPHASE (FINAL PHASE OF MITOSIS) ✰ • two daughter nuclei form in the cell, nuclear envelopes reform • chromosomes become LESS CONDENSED and MORE DEFUSED (revert back to their coiled, noodle-like form)

✰ TELOPHASE I & CYTOKINESIS ✰

✰ TELOPHASE II & CYTOKINESIS ✰ • chromosomes arrive at OPPOSITE poles • nuclei reform • chromosomes DECONDENSE

✰ TESTCROSS ✰ • given a purple flowered plant (DOMINANT phenotype) you CAN'T tell if it is homozygous dominant (PP) or heterozygous dominant (Pp)... • TESTCROSS: to predict the genotype of an individual with the dominant phenotype, you cross it with a HOMOZYGOUS RECESSIVE individual

✰ THE ACTION OF ENHANCERS AND TRANSCRIPTION ACTIVATORS ✰ 1. ACTIVATORS bind to ENHANCERS (a single enhancer is a group of distal control elements) 2. DNA bending protein BENDS the DNA 3. Mediator proteins bind to ACTIVATORS 4. Mediator proteins attract GENERAL TRANSCRIPTION FACTORS and bind to them 5. GENERAL TRANSCRIPTION FACTORS attach to DNA, recruit RNA pol, and begin transcription

✰ THE CENTRAL DOGMA ✰ • there are 4 bases in nucleotides • 20 amino acids

✰ THE REGENERATION OF ATP ✰ • ADP is a low-energy molecule, while ATP is a HIGH-energy molecule

✰ THE ROLE OF GENERAL AND SPECIFIC TRANSCRIPTION FACTORS ✰ • TWO PARTS: - DNA binding domain (domain of TF that binds to DNA) - Transcription-activation domain • DNA-BENDING protein: turns DNA over on itself • ACTIVATORS bind DNA enhancer → RNA polymerase recruitment → INCREASED transcription • as soon as the DNA-BINDING DOMAIN binds, the ACTIVATION DOMAIN is ready to bind to other regulatory PROTEINS that can cause transcription to occur → more RNA polymerase binding → INCREASED transcription of the particular gene

✰ THE ROLE OF GENERAL AND SPECIFIC TRANSCRIPTION FACTORS ✰ • TWO PARTS: - DNA binding domain (domain of TF that binds to ____) - Transcription-activation domain • DNA-________ protein: turns DNA over on itself • _________ bind DNA enhancer → RNA polymerase recruitment → INCREASED transcription • as soon as the DNA-BINDING DOMAIN binds, the ___________ DOMAIN is ready to bind to other regulatory _______ that can cause transcription to occur → more RNA polymerase binding → INCREASED transcription of the particular gene

✰ THE STRUCTURE AND FUNCTION OF TRANSFER RNA ✰ ✰ tRNA: • transfer RNA whose function is transferring an amino acid to a growing polypeptide in a ribosome • single RNA strand, ≈80 nucleotides long • can FOLD onto itself to form a 3D STRUCTURE (due to the presence of complementary stretches of nucleotide bases that can H-bond to each other) • ANTICODON: nucleotide triplet that base-pairs to a mRNA codon (they are ANTIPARALLEL to each other, like DNA) • AMINOACYL-tRNA SYNTHETASE: binds a given amino acid to tRNA

✰ THE TWO STAGES OF PHOTOSYNTHESIS ✰ 1) Light reactions (WHERE? → thylakoids) 2) Calvin cycle (WHERE? → stroma)

✰ THREE KINDS OF MICROTUBULES ✰ • ASTER → anchor asters in place • KINETOCHORE → connect to kinetochore of chromosomal centromeres; shorten in order to pull sister chromatids apart during ANAPHASE • NONKINETOCHORE → attach to EACH OTHER and lengthen in order to elongate the cell during ANAPHASE

✰ TRANSCRIPTION VS. REPLICATION ✰ • transcription does NOT code the entire DNA strand, it only does a SPECIFIC GENE • replication does the ENTIRE strand

✰ TRANSCRIPTION ✰ • TRANSCRIPTION: synthesis of a single complementary mRNA strand from a DNA template strand OR • TRANSCRIPTION: taking the DNA sequence of a gene and rewriting it in the similar alphabet of RNA SUMMARY: DNA-directed RNA synthesis

✰ TRANSLATION : INITIATION ✰ • a small ribosomal subunit binds to an mRNA molecule • an initiator tRNA base pairs with AUG (START CODON) on the mRNA • GTP HYDROLYSIS provides the energy needed for the large ribosomal subunit to attach to the small subunit

✰ TRANSLATION ✰ • TRANSLATION: the SYNTHESIS of a POLYPEPTIDE (series of amino acids) using the information from the mRNA molecule produced during transcription SUMMARY: RNA-directed synthesis of polypeptides • mRNA nucleotides are read in groups of THREE... these are CODONS

✰ TRANSLATION: ELONGATION ✰ • SUMMARY: tRNA's bring amino acids into the ribosome to add them to the growing polypeptide chain - the AA's are added to the C-terminus of the chain DETAILED: 1. CODON RECOGNITION • a tRNA enters the ribosome and arrives at the A site; its anticodon binds to the complementary codon on the mRNA strand • GTP is hydrolyzed 2. PEPTIDE BOND FORMATION • a peptide bond forms between an amino acid on the P-site tRNA and an amino acid on the A-site tRNA • the polypeptide on the P-site tRNA DETACHES and MOVES to the amino acid on the A-site tRNA 3. TRANSLOCATION • the RIBOSOME, moving along the mRNA in the 5'→3' direction, translocates the A-site tRNA to the P site • the EMPTY tRNA leaves the ribosome through the E site

✰ TRANSLATION: TERMINATION ✰ • SUMMARY: termination occurs when the A site of a ribosome arrives at one of the STOP CODONS on the mRNA 1. when the ribosome reaches a STOP CODON on the mRNA, the A site accepts a RELEASE FACTOR 2. the RELEASE FACTOR HYDROLYZES the bond between the P-site tRNA and the final amino acid of the polypeptide, thus FREEING THE POLYPEPTIDE from the ribosome 3. EVERYTHING dissociates

✰ TRANSLOCATION ✰ • occurs when a segment is MOVED from one chromosome to a NON-HOMOLOGOUS chromosome

✰ TRP OPERON OFF ✰ PRESENT tryptophan, which is the COREPRESSOR ↓ ACTIVE trp repressor protein DOES ATTACH to the OPERATOR ↓ OFF operon ↓ RNA polymerase DOES NOT attach to the operon's PROMOTER ↓ RNA polymerase DOES NOT TRANSCRIBE the operon's genes

✰ TRP OPERON OFF ✰ PRESENT tryptophan, which is the __________ ↓ _______ trp repressor protein _________ to the ________ ↓ ____ operon ↓ RNA polymerase _______ attach to the operon's __________ ↓ RNA polymerase ________ the operon's genes

✰ TRP OPERON ON ✰ ABSENT tryptophan, which is the COREPRESSOR ↓ INACTIVE trp repressor protein DOES NOT ATTACH to the OPERATOR ↓ ON operon ↓ RNA polymerase DOES attach to the operon's PROMOTER ↓ RNA polymerase DOES TRANSCRIBE the operon's genes

✰ TRP OPERON ON ✰ ABSENT tryptophan, which is the __________ ↓ ______ trp repressor protein _________ to the ________ ↓ _____ operon ↓ RNA polymerase ______ attach to the operon's __________ ↓ RNA polymerase ________ the operon's genes

✰ TWO TYPES OF PHOSPHORYLATION ✰ • SUBSTRATE LEVEL - DIRECT ATP formation through phosphate transfer from molecule → ADP - occurs in GLYCOLYSIS & CITRIC ACID CYCLE • OXIDATIVE PHOSPHORYLATION (PRODUCES MAJORITY OF ATP) - INDIRECT ATP formation through REDOX REACTIONS & through the formation of an ION GRADIENT to power a pump - driven by each transport chain

✰ TYPES OF OPERONS (NEGATIVE GENE REGULATION) ✰ • REPRESSIBLE OPERON (i.e., TRYPTOPHAN) - normally ON - can be turned OFF • INDUCIBLE OPERON (i.e., LACTOSE) - normally OFF - can be turned ON

✰ TYPES OF OPERONS (NEGATIVE GENE REGULATION) ✰ • REPRESSIBLE OPERON (i.e., _________) - normally ON - can be turned OFF • INDUCIBLE OPERON (i.e., _________) - normally OFF - can be turned ON

✰ WEAK ACIDS & BASES ✰ • a WEAK acid/base dissociates INCOMPLETELY in water; the reaction is REVERSIBLE • at any given time, a large portion of molecules of a weak acid/base is undissociated

✰ WEAK CHEMICAL BONDS ✰ • Advantage of a weak bond: - if you have a molecule that constantly needs to change and have its bonds broken, but you only have a finite amount of energy in your cell, you want LOW ENERGY bonds b/c it will take less energy to break them apart • ex: hydrogen bonds ( holds together DNA helix)

✰ WHY ALTER THE ENDS? ✰ • the modifications made in the nucleus during RNA processing serve MANY FUNCTIONS: 1. PROTECT the RNA from degradation by hydrolytic enzymes 2. FACILITATE EXPORT of mature mRNA from the nucleus 3. FACILITATE START OF TRANSLATION by helping ribosomes attach to 5' end of mRNA once mRNA reaches the cytoplasm

✰ WHY ARE CHANGES IN CHROMOSOMAL STRUCTURE PROBLEMATIC? ✰ • if you're HOMOZYGOUS for a large deletion, it can be LETHAL • in INVERSIONS, GENE EXPRESSION may CHANGE

✰ WHY SHOULDN'T CELLS EXPRESS EVERY GENE? ✰ • ENERGY CONSERVATION: cells are exposed to changing environments, and they DO NOT want to waste energy creating something they DO NOT need • MULTICELLULARITY: organisms need different PROTEINS in different cells ✪ DIFFERENTIAL EXPRESSION OF GENES allows cells to conserve energy and allows for different types of cells

✰ WHY SHOULDN'T CELLS EXPRESS EVERY GENE? ✰ • ENERGY ____________: cells are exposed to changing environments, and they DO NOT want to waste energy creating something they DO NOT need • MULTICELLULARITY: organisms need different _________ in different cells ✪ ______________ allows cells to conserve energy and allows for different types of cells

✰ WITHOUT OXYGEN ✰ • O₂ is at the END of the electron transport chain • glycolysis can STILL OCCUR without O₂ (you will get • AEROBIC CELLULAR RESPIRATION: C.R. in which O₂ is a reactant • FERMENTATION: C.R. in which O₂ is NOT a reactant

✰ X INACTIVATION IN FEMALE MAMMALS ✰ • during embryonic development, almost all of ONE X chromosome becomes INACTIVATED - all offspring will have SAME inactivated X • the INACTIVATED X in each cell of a female condenses into a BARR BODY • at random, half of cell will have an inactivated X and half will have activated X... so, you will end up with a female that has half of her cells possessing ONE PHENOTYPE and the other half of her cells possessing a DIFFERENT PHENOTYPE... i.e., calico cats

✰ X-INACTIVATION: CALICO CATS ✰ • if a female cat is heterozygous for black and tan alleles of a coat color gene found on the X, she will inactivate her two Xs (and thus, the two alleles of the coat color gene) at random in different cells during development • as a result, the cat has a tortoise shell coat pattern, made up of alternating patches of BLACK and TAN fur - BLACK patches come from groups of cells in which the X with the black allele is active - TAN patches come from cells in which the X with the tan allele is active

✰ X-LINKED GENES ✰ • ♀️- XX (HOMOZYGOUS → 2 ALLELES) • ♂️- XY (HEMIZYGOUS → 1 ALLELE) • X-LINKED RECESSIVE DISORDERS: - MORE COMMON IN MEN - passed from MOTHER → SON (b/c since men receive their Y from their FATHER, they therefore receive their X from their MOTHER) - i.e., colorblindness, hemophilia, XLA (🚫 antibodies in cells) • ANYTHING on the X or Y allele of a male's chromosomes will ALWAYS be expressed... therefore, men can 🚫 be carriers for an X-linked gene

✰ mRNA DEGRADATION ✰ • the FINITE lifespan of an mRNA molecule in the cytoplasm depends on the length of the POLY-A TAIL at the 3' end • once RNases devour the poly-A tail and reach the UNTRANSLATED REGION (UTR), a signal tells the mRNA that it is finished translating (hence the name UTR) so that it does not go on to devour the stop codon

✰ mRNA DEGRADATION ✰ • the FINITE lifespan of an mRNA molecule in the cytoplasm depends on the length of the ____________ at the 3' end • once RNases devour the poly-A tail and reach the ________, a signal tells the mRNA that it is finished translating (hence the name UTR) so that it does not go on to devour the stop codon

a) 12 fg

🕹CLICKER QUESTION🕹 Based on the following figure, how much DNA is present in a gamete of Saccharomyces cerevisiae? a) 12 fg b) 24 fg c) 40 fg d) 48 fg

c) Pp x Pp

🕹CLICKER QUESTION🕹 510 purple flower and 170 white flowers were observed from many crossings of the same pea plants. What genotypes are the parents? a) PP x PP b) Pp X PP c) Pp x Pp d) pp x pp

c) One cell with 4 copies of each chromosome and one cell with 0 copies of each chromosome

🕹CLICKER QUESTION🕹 A cell with two copies of each chromosome had problems with the spindle that caused the sister chromatids to remain attached to each other and to only one spindle pole. Which of the following cells would result? a) One cell with 2 copies of each chromosome and one cell with 2 copies of each chromosome b) One cell with 3 copies of each chromosome and one cell with 1 copy of each chromosome c) One cell with 4 copies of each chromosome and one cell with 0 copies of each chromosome d) One cell with 1 copy of each chromosome and one cell with 1 copy of each chromosome

e) Neither c nor d is possible. * alternative RNA splicing CAN NOT rearrange the exons... it can only INCLUDE them, or EXCLUDE them

🕹CLICKER QUESTION🕹 A eukaryotic gene has a pre-mRNA with four exons (1, 2, 3, 4). Which of the following arrangements of exons would NOT be possible after alternative splicing? a) 1, 2, 3, 4 b) 1, 3, 4 c) 1, 3, 3, 4 d) 1, 3, 2, 4 e) Neither c nor d is possible.

A. send a sympathy card since the hamster is dead. EXPLANATION: • living organisms can NEVER be in equilibrium, there must be gradient in order for ATP to form

🕹CLICKER QUESTION🕹 A friend tells you that his hamster has reached equilibrium. You... A. send a sympathy card since the hamster is dead. B. congratulate your friend on teaching the hamster a trick. C. say that the hamster must produce lots of ATP.

b) two gamete types: py and Py

🕹CLICKER QUESTION🕹 A pea plant is heterozygous for flower color and homozygous recessive for seed color. Flower color is designated with the P/p alleles and seed color is designated with the Y/y alleles. What types of gametes can it produce? a) two gamete types: pp and PP b) two gamete types: py and Py c) four gamete types: pY, py, PY, and Py d) four gamete types: pP, Yy, pY, and Py e) one gamete type: PpYy

b) two gamete types: p and P

🕹CLICKER QUESTION🕹 A pea plant is heterozygous for flower color. Flower color is designated with the P/p alleles. What types of gametes can it produce? a) two gamete types: pp and PP b) two gamete types: p and P c) four gamete types: pp, p, PP, and P d) one gamete type: PpYy

D. The reaction would proceed by itself (but might be very slow)

🕹CLICKER QUESTION🕹 A reaction has a ∆G of -5.6 kcal/mol. Which of the following is most likely to be true? A. The reaction could be coupled to power an endergonic reaction with a ∆G of +8.8 kcal/mol. %C. To take place, the reaction would need to couple to ATP hydrolysis. D. The reaction would proceed by itself but might be very slow. E. Both b & c are correct

C. The inner membrane was derived from folding of the prokaryotic plasma membrane and the outer membrane from folding in of the eukaryotic plasma membrane

🕹CLICKER QUESTION🕹 According to the endosymbiosis theory, what is the most likely explanation for the origin of the two mitochondrial membranes? A. Both inner and outer membranes were derived from folding of the prokaryotic plasma membrane B. Both inner and outer membranes were derived from folding in of the eukaryotic plasma membrane C. The inner membrane was derived from folding of the prokaryotic plasma membrane and the outer membrane from folding in of the eukaryotic plasma membrane D. The inner membrane was derived from folding of the eukaryotic plasma membrane and the outer from folding in of the prokaryotic plasma membrane

E. do not dissolve well in water

🕹CLICKER QUESTION🕹 All lipids A. are made from glycerol and fatty acids B. contain nitrogen C. have low energy content D. are acidic when mixed with water E. do not dissolve well in water

B. To the left - the water will dilute the more concentrated side in order to create equilibrium

🕹CLICKER QUESTION🕹 Assuming that the solute cannot diffuse through the membrane, in which direction does the water move? A. To the right B. To the left

d) M and N

🕹CLICKER QUESTION🕹 Consider the replication bubble diagrammed at the right where the origin of replication is denoted with the dash. Which letters represent LAGGING strands? a) L and M b) N and O c) L and O d) M and N e) L and N

c) L and O

🕹CLICKER QUESTION🕹 Consider the replication bubble diagrammed at the right where the origin of replication is denoted with the dash. Which letters represent LEADING strands? a) L and M b) N and O c) L and O d) M and N e) L and N

e) ATP synthesis will decrease; oxygen consumption will stay roughly the same. • the entire process would work the same, but chemiosmosis wouldn't work as well b/c the protons would BYPASS ATP SYNTHASE, thus decreasing the number of ATP's made

🕹CLICKER QUESTION🕹 Drugs known as uncouplers facilitate diffusion of protons across the membrane. With an uncoupler, what will happen to ATP synthesis and oxygen consumption if the rates of glycolysis and the citric acid cycle stay the same? a) Both ATP synthesis and oxygen consumption will decrease. b) ATP synthesis will decrease; oxygen consumption will greatly increase. c) ATP synthesis will increase; oxygen consumption will decrease. d) Both ATP synthesis and oxygen consumption will increase. e) ATP synthesis will decrease; oxygen consumption will stay roughly the same

A. the beginning of G₁

🕹CLICKER QUESTION🕹 Eukaryote Cell X has half as much DNA as three other cells in an actively dividing tissue. Cell X is most likely in? A. the beginning of G₁ B. the end of G₂ C. the end of S D. the beginning of M

less polar water → less attractions between one molecule's O (δ⁻) and another molecule's H (δ⁺) → fewer hydrogen bonds → less energy input to break these hydrogen bonds → less water will vaporize from skin and release excess heat

🕹CLICKER QUESTION🕹 Explain why the following statement is CORRECT: D. If water were LESS polar, sweating would be a less effective means of keeping cool

less polar water → less attractions between one molecule's O (δ⁻) and another molecule's H (δ⁺) → fewer hydrogen bonds → decreased cohesion (clinging of water to itself) → decreased surface tension → the insect would sink

🕹CLICKER QUESTION🕹 Explain why the following statement is INCORRECT: A. If water were LESS polar, heavier insects than water striders would be able to walk on the surface of a pond

less polar water → less attractions between one molecule's O (δ⁻) and another molecule's H (δ⁺) → fewer hydrogen bonds → decreased cohesion (clinging of water to itself)

🕹CLICKER QUESTION🕹 Explain why the following statement is INCORRECT: B. If water were LESS polar, increased cohesion would lead to increased upward water transport in plants

less polar water → less attractions between one molecule's O (δ⁻) and another molecule's H (δ⁺) → fewer hydrogen bonds → decreased specific heat of water (less energy required to increase the temperature of water) → water heats up faster

🕹CLICKER QUESTION🕹 Explain why the following statement is INCORRECT: C. If water were LESS polar, water temperature of ponds and pools would increase more slowly when in sunlight

C. 10 *you need one less H₂O; you have 11 molecules, so you need 10 reactions to break it down

🕹CLICKER QUESTION🕹 How many molecules of H₂O are needed to completely hydrolyze a polymer that is 11 monomers long? A. 8 B. 9 C.10 D.11 E.12

q is the frequency (%) of RECESSIVE alleles in the gene pool ↓ a percentage is a FRACTION, meaning you'll need the number of copies of the specified allele DIVIDED by the total number of copies (so the total recessive and dominant alleles) of the gene ↓ so, FIRST, calculate the # of recessive allele copies and the # of dominant allele copies ↓ 300 CRCR 200 CRCW 50 CWCW # of recessive white alleles = 2*CWCW + 1*CRCW = 2(50) + 1(200) = 300 # of dominant red alleles = 2*CRCR + 1*CRCW = 2(300) + 1(200) = 800 ↓ now, calculate q q=(# of copies of recessive allele CW) ÷ (total # of CR/CW alleles in population) q=300÷(300+800)=.27 a. 0.27

🕹CLICKER QUESTION🕹 If there are 300 red flowers , 200 pink flowers and and 50 white flowers, what is the value for q (white alleles)? a. 0.27 b. 0.36 c. 0.5 d. 25 e. 700

D. Golgi

🕹CLICKER QUESTION🕹 If you were studying mutant cells and found many proteins in the wrong location, where is the mutation having the greatest effect? A. DNA B. nuclear envelope C. smooth endoplasmic reticulum D. Golgi E. lysosome

d) Always synthesize β-galactosidase.

🕹CLICKER QUESTION🕹 Imagine an E. coli cell with a mutation that makes the lac repressor protein completely inactive. Which of the following would be true of that cell? a) Synthesize β-galactosidase only when lactose is absent. b) Synthesize β-galactosidase only when lactose is present. c) Never synthesize β-galactosidase. d) Always synthesize β-galactosidase.

a) homozygous red-eyed females with white-eyed males

🕹CLICKER QUESTION🕹 In Drosophila, white eyes are due to an X-linked recessive allele (Xw). Which of the following crosses could not result in a white-eyed Drosophila male? a) homozygous red-eyed females with white-eyed males b) homozygous white-eyed females with red-eyed males c) heterozygous red-eyed females with white-eyed males d) heterozygous red-eyed females with red-eyed males

c) only CAP

🕹CLICKER QUESTION🕹 In normal E. coli cells, in which the lac operon is "high," which combination of CAP and lac repressor proteins is bound to the lac operon? a) both CAP and lac repressor b) neither CAP nor lac repressor c) only CAP d) only lac repressor

C. The black curve has a higher activation energy

🕹CLICKER QUESTION🕹 In the energy diagram, what is the difference between the red and black curves? A. The red curve requires ATP. B. The black curve has a higher ∆G C. The black curve has a higher activation energy D. b and c are correct E. a, b, & c are correct

c) meiosis I metaphase • notice that the TETRAD is present

🕹CLICKER QUESTION🕹 In this cell, what phase is represented? a) mitotic metaphase b) meiosis I anaphase c) meiosis I metaphase d) meiosis II anaphase e) meiosis II metaphase

a) prokaryotes

🕹CLICKER QUESTION🕹 In which group of organisms could you see transcription and translation occurring simultaneously? a) prokaryotes b) eukaryotes c) both d) neither

b) 25%

🕹CLICKER QUESTION🕹 John, age 47, has just been diagnosed with Huntington's disease, which is caused by a rare dominant allele (he is heterozygous). His daughter, age 25, has a 2-year-old son. No one else in the family has the disease. Without knowing anything about the 25-year-old daughter's genotype, what is the probability that the 2-year-old son will eventually develop the disease? a) 0% b) 25% c) 50% d) 75% e) 100%

B. False

🕹CLICKER QUESTION🕹 Lipids do not have monomeric units, therefore they do not use dehydration reactions to form larger molecules A. True B. False

c) The first few days of antibiotics kill off the most susceptible bacteria, making people feel better. Then, when people stop taking the antibiotics, the resistant bacteria that survived reproduce to create a more resistant population.

🕹CLICKER QUESTION🕹 MRSA infections are occurring at alarming rates. One reason for this could be that people do not finish their antibiotics. Which of the following is the most likely reason that this could lead to MRSA? a) Antibiotics take some time to start working, giving the bacteria time to mount defenses against the antibiotics over a few days. b) Because antibiotics are often taken when there is no bacterial infection, the antibiotics are losing their antibacterial properties due to lack of use. c) The first few days of antibiotics kill off the most susceptible bacteria, making people feel better. Then, when people stop taking the antibiotics, the resistant bacteria that survived reproduce to create a more resistant population.

D. to generate heat

🕹CLICKER QUESTION🕹 Newborn mammals have a specialized tissue called brown fat, where cells catabolize fat without capturing the energy to reduce electron carriers or drive ATP formation. Why would they do this? A. to synthesize glucose from CO₂ B. to directly power muscle contraction C. to provide energy for endergonic biosynthetic reactions D. to generate heat

B. different elements

🕹CLICKER QUESTION🕹 One atom has 7 protons and 7 neutrons. Another atom has 6 protons and 7 neutrons. The two atoms... A. are isotopes of the same element B. are different elements C. have the same atomic number D. A & B are correct E. A, B, & C are correct

c) Yes. They have similar bone structure inherited from a common ancestor.

🕹CLICKER QUESTION🕹 Should bat wings be considered homologous to whale flippers? Which of the following is the best answer and argument? a) Yes. They are both limbs and are both used for locomotion. b) No. They have very different uses—flight versus swimming. c) Yes. They have similar bone structure inherited from a common ancestor. d) No. There is no common ancestor of bats and whales.

A. on the exterior surface of the protein • the amino acid changes from charged (hydrophilic) → hydrophobic • if the hydrophobic amino acid is on the INTERIOR of the protein (thus, away from the water) it is unlikely to change shape • *HYDROPHILIC glutamic acid would be content with being on the EXTERIOR of the protein, but if it were to become HYDROPHOBIC, the amino acid would change shape to try to avoid the water*

🕹CLICKER QUESTION🕹 Sickle-cell disease is caused by a mutation in the β-hemoglobin gene that changes a CHARGED amino acid, glutamic acid, to valine, a HYDROPHOBIC amino acid. This changes the shape and thus the function of the protein. Where in the protein would you expect to find glutamic acid? A. on the exterior surface of the protein B. in the interior of the protein C. Either A or B could be correct

B. 30% EXPLANATION: • if 20% of a DNA molecule is thymine nucleotides, then that means that ANOTHER 20% of the molecule is adenine ↓ • so far, 20+20=40% of the molecule (in the form of TWO bases) is accounted for ↓ • that leaves 100-40=60% of the molecule (in the form of TWO bases) UNACCOUNTED for ↓ • 60 ÷ 2 = 30% ↓ • the rest of the molecule is 30% guanine, 30% cytosine

🕹CLICKER QUESTION🕹 Suppose 20% of a DNA molecule is thymine nucleotides. How much of the DNA is guanine? A. 20% B. 30% C. 60% D. 80% E. 100%

c) gene flow • recall that gene flow is the transfer of ALLELES from ONE POPULATION TO ANOTHER • the BSC states that exchange of genes CAN NOT be random... it must produce VIABLE, FERTILE offspring

🕹CLICKER QUESTION🕹 The biological species concept relies on a disruption of which aspect of population genetics? a) mutation b) selection c) gene flow d) genetic drift e) all of the above

e) 5'-ACUAUGCACCG-3' EXPLANATION: • mRNA is read in the 5'→3' direction, so to get the sequence of the mRNA strand IN THIS QUESTION, you must read the non-template/coding strand's sequence BACKWARDS b/c it's given in the 3'→5' direction, and you also must replace T (thymine) with U (uracil) as you go, and the resulting sequence IS the mRNA sequence • if the non-template strand/coding strand's sequence is given in the 5'→3' direction, just REPLACE the T's with U's

🕹CLICKER QUESTION🕹 The non-template strand of a given gene includes the sequence 3′-GCCACGTATCA-5′. What is the sequence of the mRNA strand? a) 3′-CGGTGCATAGT-5′ b) 5′-CGGTGCATAGT-3′ c) 5′-GCCACGUAUCA-3′ d) 3′-CGGUGCAUAGU-5′ e) 5'-ACUAUGCACCG-3'

b) This allele is passed to all male but no female offspring

🕹CLICKER QUESTION🕹 There are some genes on the Drosophila Y chromosome that are NOT on the X chromosome. Imagine that a new allele arises on the Y chromosome that decreases the size of those individuals. Which of the following statements is accurate with regard to this situation? a) This allele is passed to all offspring of a male with the allele. b) This allele is passed to all male but no female offspring of a male with the allele. c) This allele is passed to all offspring of a female with the allele. d) This allele is passed to all male but no female offspring of a female with the allele. e) This allele is passed to all offspring of both males and females with the allele.

FALSE • MITOCHONDRIA are present in BOTH 🐖 and 🌿 cells!!!

🕹CLICKER QUESTION🕹 True or False: Mitochondria are present only in animal cells and chloroplasts are present only in plant cells

e) 5

🕹CLICKER QUESTION🕹 Using this phylogenetic tree, select which number refers to the most recent common ancestor between hippos and wolves. a) 1 b) 2 c) 3 d) 4 e) 5

A. competitive inhibitors • when talking about COMPETITIVE INHIBITION, the amount of substrate DOES MATTER b/c they are COMPETING • when talking about NONCOMPETITIVE (ALLOSTERIC) INHIBITION, the amount of substrate DOES NOT MATTER b/c no matter how much substrate you have, they won't be able to bind to the active site b/c the inhibitor has CHANGED THE ENZYME'S SHAPE

🕹CLICKER QUESTION🕹 Vioxx and other prescription non-steroidal anti-inflammatory drugs (NSAIDs) are inhibitors of the COX-2 enzyme. High substrate concentrations reduce the efficacy of inhibition by these drugs. Therefore, these drugs are A. competitive inhibitors B. noncompetitive inhibitors C. allosteric regulators D. Both b & c are correct

c. CCA EXPLANATION: • the codon for Trp is 5'-UGG-3' • a codon and its anticodon is ANTIPARALLEL • therefore, the anticodon is 3'-CCA-5'

🕹CLICKER QUESTION🕹 What is the 5′→3′ sequence on the anticodon of the tryptophan (Trp) tRNA? a) UGG b) GGU c) CCA d) ACC

D. hydrogen bond • B. is INCORRECT b/c the polar covalent bond is WITHIN the H₂O molecule

🕹CLICKER QUESTION🕹 What type of bond would you expect between two H₂O molecules? A. single bond B. polar covalent bond C. ionic bond D. hydrogen bond E. A & D are correct

a) 1 nucleotide frameshift

🕹CLICKER QUESTION🕹 What type of mutation would probably have the most severe effect? a) 1 nucleotide frameshift b) 3 nucleotide frameshift c) 1 missense mutation d) 1 silent mutation

d) metaphase alignment during meiosis I

🕹CLICKER QUESTION🕹 When does independent assortment happen? a) pairing of homologs during meiosis I b) separation of homologs during anaphase II c) separation of homologs during meiosis II d) metaphase alignment during meiosis I e) telophase separation during meiosis I

C) two layers of phospholipids with proteins spanning the layers and on the surface of the layers

🕹CLICKER QUESTION🕹 Which best describes a biological membrane? A) two layers of phospholipids with proteins embedded between the two layers B) a mixture of covalently linked phospholipids and proteins that determines which solutes can cross the membrane and which cannot C) two layers of phospholipids with proteins spanning the layers and on the surface of the layers D) a fluid bilayer in which phospholipids and proteins move freely around and across the membrane E) A bilayer of phospholipids with each layer covered on the outside with proteins

d) ATP is produced—the intermembrane space

🕹CLICKER QUESTION🕹 Which incorrectly matches process and location? a) Oxygen gas is produced—the thylakoid space b) Activated chlorophyll donates an electron—the thylakoid membranes c) NADPH is oxidized to NADP⁺—the stroma d) ATP is produced—the intermembrane space e) Rubisco catalyzes carbon fixation—the stroma

e) no selection

🕹CLICKER QUESTION🕹 Which of the Hardy-Weinberg conditions is being violated? Some moths on a tree are easier to see due to their lighter color and therefore are eaten by predators more often. a) large population size b) no mutation c) no gene flow d) random mating occurring e) no selection

C. Blood

🕹CLICKER QUESTION🕹 Which of the following is buffered by carbonic acid (H₂CO₃)? A. Bone B. Lung C. Blood D. Intestine E. Skin

A. Both regenerate the starting material after molecules enter and leave the cycle

🕹CLICKER QUESTION🕹 Which of the following is correct about the Calvin Cycle & the Citric Acid Cycle? A. Both regenerate the starting material after molecules enter and leave the cycle B. Citric acid cycle is anabolic C. Calvin cycle is catabolic D. all of the above are correct

B. Energy storage

🕹CLICKER QUESTION🕹 Which of the following is one of the primary functions of carbohydrates? A. Catalyze chemical reactions B. Energy storage C. Protect cell organelles D. Store cell's information

A. Natural selection • natural selection ALWAYS selects for the traits that best improve a species' chances for survival and reproduction (and therefore, its FITNESS)

🕹CLICKER QUESTION🕹 Which of the following mechanisms would ALWAYS lead to adaptive evolution of a population? A. Natural selection B. Gene flow C. Bottleneck effect D. Founder effect E. All of the above would lead to adaptive evolution

C. Mutation of one proto-oncogene • 1 active oncogene + 1 active tumor suppressor gene... OKAY • 1 active oncogene + 0 active tumor suppressor genes... BAD (b/c you basically 🚫 have brakes in your car anymore to stop the cancerous gene from growing!!!)

🕹CLICKER QUESTION🕹 Which of the following scenarios would most likely lead to the development of cancerous cells? A. Introducing a proto-oncogene into a cell B. Introducing a tumor-suppressor gene into a cell C. Mutation of one proto-oncogene D. Mutation of one tumor-suppressor gene

b) The repressor is inactive, and RNA polymerase can synthesize mRNA

🕹CLICKER QUESTION🕹 Which of the following statements about the trp operon is true when the cell is actively translating? a) The repressor is active and binds to the operator b) The repressor is inactive, and RNA polymerase can synthesis mRNA c) The operator is bound, and mRNA is made d) The corepressor binds to the repressor

D. Prokaryotes have groups of genes with a single promoter and eukaryotes have coordinately scattered genes across the chromosome

🕹CLICKER QUESTION🕹 Which of the following statements is true about transcriptional regulation in prokaryotes and eukaryotes? A. Both prokaryotes and eukaryotes have coordinately scattered genes scattered across the chromosome B. Both prokaryotes and eukaryotes have groups of genes together in the chromosome under the control of a single promoter C. Prokaryotes have coordinately scattered genes across the chromosomes and eukaryotes have groups of genes with a single promoter D. Prokaryotes have groups of genes with a single promoter and eukaryotes have coordinately scattered genes across the chromosome

C. it occurs in the cytosol • at the end of glycolysis, there is still a MASSIVE amount of energy stored in PYRUVATES

🕹CLICKER QUESTION🕹 Which statement about glycolysis is true? A. It splits water B. It produces FADH₂ C. It occurs in the cytosol D. By the end of the reaction, the majority of the energy from glucose is in ATP and NADH E. Both C & D are correct

B. It makes ATP through substrate-level phosphorylation

🕹CLICKER QUESTION🕹 Which statement about the citric acid cycle is true? A. It occurs during the movement from the cytosol through the mitochondrial membranes B. It makes ATP through substrate-level phosphorylation C. By the end, glucose has been completely reduced D. It occurs in the cytoplasm E. By the end, the majority of the energy from glucose is in CO₂

D. phospholipid bilayer (aka cell membrane)

🕹CLICKER QUESTION🕹 Which structure is common to all three domains of life? A. nucleus B. endoplasmic reticulum C. mitochondria D. phospholipid bilayer E. endocytic vesicles

c) Originally, all fish in the population had eyes and could see. However, in the dark, there was no longer selection for sight, and eyes were eventually lost due to random mutations.

🕹CLICKER QUESTION🕹 You discover fish living in a cave with no natural light. The fish have no eyes, but they do have eye sockets. How would Darwin explain this? a) The fish were in a dark environment and therefore didn't need eyes. Over time, they used their developmental energy for more useful features, so they lost their eyes because they didn't use them. b) The fish never had eyes but are slowly evolving to have them because they might need them in the future. c) Originally, all fish in the population had eyes and could see. However, in the dark, there was no longer selection for sight, and eyes were eventually lost due to random mutations.

a) The fish were in a dark environment and therefore didn't need eyes. Over time, they used their developmental energy for more useful features, so they lost their eyes because they didn't use them.

🕹CLICKER QUESTION🕹 You discover fish living in a cave with no natural light. The fish have no eyes, but they do have eye sockets. How would Lamarck explain this? a) The fish were in a dark environment and therefore didn't need eyes. Over time, they used their developmental energy for more useful features, so they lost their eyes because they didn't use them. b) The fish never had eyes but are slowly evolving to have them because they will need them someday. c) Originally, all fish in the population had eyes and could see. However, in the dark, there was no longer selection for sight, and eyes were eventually lost due to random mutations.

a) clam

🕹CLICKER QUESTION🕹 You find a section of sedimentary rock in which some fossils have been exposed. You notice that a clam fossil is in a deeper layer than a fish fossil. Which fossil is most likely older? a) clam b) fish c) not enough data to answer

d) pp x pp

🕹CLICKER QUESTION🕹 0 purple flower and 170 white flowers were observed from many crossings of the same pea plants. What genotypes were the parents? a) PP x PP b) Pp X PP c) Pp x Pp d) pp x pp

C. taking electrons from food and giving them to oxygen to make water, using the energy released to drive ATP formation

🕹CLICKER QUESTION🕹 Cellular respiration can best be described as A. using energy released from breaking high-energy organic molecules to force ATP formation from ADP and phosphate. B. taking electrons from food and giving them to phosphate to make ATP. C. taking electrons from food and giving them to oxygen to make water, using the energy released to drive ATP formation. D. converting higher-energy organic molecules to lower-energy organic molecules and using the energy released to drive ATP formation.

D) facilitated diffusion depends on an existing energy gradient acting on the transported substance, while active transport makes such a gradient

🕹CLICKER QUESTION🕹 Which of the following is a correct distinction between facilitated diffusion and active transport? A) active transport requires conformational changes in the transport protein, and facilitated diffusion does not. B) active transport requires an integral membrane protein to carry out the transport, and facilitated diffusion does not. C) facilitated diffusion requires a protein within the membrane, and active transport does not. D) facilitated diffusion depends on an existing energy gradient acting on the transported substance, while active transport makes such a gradient. E) facilitated diffusion requires cellular energy (usually ATP), but active transport does not.

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