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76 Cards in this Set
- Front
- Back
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Organelle
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Small structure that carries out specific cellular function
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Nucleus Components (3)
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- Genome
- Nucleolus - Nuclear Envelope |
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Nucleus
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- Primary feature distinguishing them from prokaryotes is DNA enclosed in a nucleus
- Replication, transcription, and splicing occur in the nucleus |
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Chromosome
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- Genome organized into linear ds-DNA
- Humans have 23 unique, because we are diploid (2n) we have 46 |
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Centromere
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Near middle of the chromosome, makes sure they are sorted properly in mitosis/meiosis
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Telomere
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- Ends of the chromosomes, contain lots of repeats
- Maintain chromosome ends during replication |
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Euchromatin
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Loosely packed regions where genes can be activated
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Heterochromatin
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densely packed regions of DNA where genes are inaccessable
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Locus
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specific region of a gene mapped out
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Nucleolus
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- Region in the nucleus specializing in being a ribosome factory
- No membrane separation, largest in sells synthesizing a lot of protein - Site of transcription of RNA by RNA Poly I |
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Nuclear Envelope
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- 2 Lipid Bilayers
- Have nuclear pores embedded in them |
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Nuclear Pores
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- Allow passage of materials in and out of the nucleus
- <60 kDa, freely passes through - Large proteins need special sequence that allows ribosomes to move them into the nucleus |
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Mitochondria
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- Site of oxidative phosphorylation
- Contains pyruvate dH, Krebs enzymes - Has its own circular genome which displays maternal inheritance - ATP made here and transported out - Outer Membrane -> IMS -> Matrix |
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Cristae Purpose
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- Folds increase the surface area which allows for more Krebs
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Rough ER
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- Site of major protein synthesis
- Also site of posttranslational modification, disulfide bond formation - "Rough" because of large amount of ribosomes bound to surface |
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Where do proteins synthesized in the Rough ER end up? (3)
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- Secreted into cellular environment
- Turn into integral membrane proteins - Stay in ER - All transported by vessicles |
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Smooth ER
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- In liver, help with detoxification
- In gonads, help with steroid hormone biosynthesis |
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Golgi Apparatus
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- Modifies proteins from Rough ER
- Sorts, sends proteins to correct destination - Synthesizes polysaccharides - Unidirectional from cis-medial-trans - Proteins leave in vessicle sacs |
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Lysosome
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- Degrades macromolecules by hydrolysis
- Made in Rough ER - Uses enzymes called Acid Hydrolases |
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Acid Hydrolases
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- Enzymes of the lysosome
- Only hydrolyzes stuff in an acid environment - Lysosyme pH is 5, cytoplasm is 7, so it won't destroy the cell if it ruptures |
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Peroxisome
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- Has enzymes that produce H2O2 (poison to cell) and converts H2O2 to H2O + O2
- Important site of lipid breakdown - Important site of detoxification in the liver |
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Lipid Bilayer Components
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- Phospholipid
- Glycolipids - Cholesterol - Cell surface receptors |
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What can diffuse through the lipid bilayer? What can't?
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- Water passes through easily with special channel
- Nonpolar molecules pass through easily (carbon dioxide, oxygen, steroids) - Polar molecules need membrane proteins |
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Types of Proteins (3)
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- Peripheral (attached to integral proteins)
- Integral (embedded in the membrane) - Transmembrane (in the membrane) |
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Unsaturated
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- One or more double bond
- Kinky - Increase double bonds, increase fluidity |
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Saturated
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No double bonds
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Passive Transport (2)
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- No cellular energy required
- Any thermodynamically favorable movement of a solute across a membane (eg, DOWN the concentration gradient) - Simple and Facilitated |
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Simple Diffusion
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- Passive
- Without help from a protein, simply diffuses across membrane (any nonpolar molecule can do this) |
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Facilitated Diffusion
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- Movement of solid down a gradient
- When bilayer impermeable, uses protein channels, (ion, voltage gated) |
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Diffusion
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- Tendency for liquids or gases to fully occupy available volume
- Down a gradient from high to low, continues until even |
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Osmosis
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- Flow of water
- Solvent moves toward equilibrium with solute (diffusion usually opposite osmosis) |
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Isotonic
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Equal solute = solvent inside/outside of the cell
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Hypotonic
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Outside is greater than the inside
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Hypertonic
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Inside is greater than outside
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Active Transport
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- Movement of molecules AGAINST gradient
- Requires energy (ATP) - Generally coupled with a thermodynamically favorable reaction to make going against gradient okay |
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Where does the Na, K ATPase act?
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EVERYWHERE! ALL CELLS! EVERYWHERE! ALL CELLS!!!
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What does the Na, K ATPase do?
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- Maintain osmotic balance
- Establish resting membrane potential for action potential, where the inside of the cell is negative - 3 Na OUT, 2 K IN using ATP!!! |
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Cell Cycle (Go, G1, S, G2, M)
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Go - Stuck permanently in interphase, tend to be specialized cells
S - Cells replicating DNA here G1/G2 - Growth phases M - Mitosis |
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Homologous Chromosomes
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Equal but NONIDENTICAL
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Sister Chromatids
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IDENTICAL COPIES of cells attached at centromere
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Gene
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- Length of DNA encoding for particular product
- Fundamental unit of inheritance |
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Allele
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- Different version of a gene
- Recall we have two copies of every gene |
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Classic Dominance
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C > c
One allele is greater than the other phenotypically |
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Incomplete Dominance
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Phenotype is a mixture of both alleles
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Codominance
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- Both alleles are expressed and not completely dominant
- Classic example is blood type |
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Pleiotropism
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When a gene is altered and affects seemingly unrelated phenotypic traits at once
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Polygenism
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Complex traits influenced by many different genes, like height, skin color
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Penetrance
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- Likelihood a person with a given genotype will express phenotype
- 95% penetrance means 5% don't express the trait |
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Where does Meiosis take place?
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Men - Testes
Females - Ovaries |
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Tetrads
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Paired Homologous Chromosomes
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When does Recombination Occur?
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- Prophase I of Meiosis
- Swappage of genes between lined up homologous chromosomes - Source of genetic variation |
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Nondisjunction
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Failure of chromosomes to separate properly in either anaphase I or II
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Mendelian Genetic Laws (2)
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- Alleles of a gene separate independently (multiplication) "AND"
- Two alleles are passed on and separated (addition) "OR" |
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Linkage
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- Failure of genes to display independent assortment
- Genes on SAME chromosome may not sort independently, this is the exception |
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Frequency of Recombination Equation
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(Number of Recombinants/Total Number of Offspring)
Numerator is the number of recombinant phenotypes. |
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What is the frequency of recombination indicative of?
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Distance of genes! Greater the rate of recombination, farther away they are
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Sex Linked Traits
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- Traits determined by X/Y chromosomes
- Y traits only passed to males - Women are carriers of recessive diseases because they have two X - Men always express X linked recessive traits |
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Population
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Group of species that mate and reproduce with each other
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Gene Pool
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Sum of all the genetic info in a population
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Hardy Weinberg Theory (5)
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- Frequencies of alleles in a gene pool of a population will NOT CHANGE over time
- Magical things must happen: no mutation, no migration, no natural selection, random mating, and large population - Preventing new alleles from being added to the population |
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Hardy Weinberg Equations (2)
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p + q = 1
p² + 2pq + q² = 1 |
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Evolution
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CHANGES OVER MILLIONS OF FREAKING YEARS
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Natural Selection
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- mechanism causing evolution
- acts on phenotypes |
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Fitness
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- How well an animal is physically able to pass on alleles to the next generation
- HERITABLE traits |
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Directional Selection
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Bell curve, average
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Divergent Selection
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- Removes average
- Leaves extremes - Possibly creates new species |
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Stabilizing Selection
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- Extremes removed
- Average increased |
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Kin Selection
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- Sacrifice self to save alleles an animal might share with another individual
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Prezygotic Barriers
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- Prevent zygote from ever forming
- Ecological, temporal, mechanic, behavioral, gametic |
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Postzygotic Barriers
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- Prevent development of sexual hybrids
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Speciation
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Creation of a new species!
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Homologous Structure
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- Same origin, different function
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Analogous Structure
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- Same function but not due to shared ancestry (arms of a human, wings of a bat)
- Due to convergent evolution |
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Convergent Evolution
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- Similar traits in unrelated lineages
- Generally caused by a common biome, as similar environments will select for traits that are best suited for that niche even if they aren't related - Where we get "analogous" structures |
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Divergent Evolution
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- Divergent selection separates a species' extreme genotypes into two different species over times
- What causes "branches" in a cladogram |
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Parallel Evolution
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- Similar characteristics due to same selective pressures
- Mammals and Marsupials |
