First semester Exam Flashcards
Evolution
Change in allele frequency over time
Artificial selection
the human selection of different desirable traits
Natural selection
traits that improve survival or reproduction will accumulate in the population
Steps of Natural selection
- variation
- overproduction
- competition
- survival of the fittest
- differential reproduction
- generations
Evidence for evolution
fossil record (transitional fossils), artificial selection (antibiotics), anatomical/morphological (structure), molecular data (DNA code)
Homologous structures
similar features indicate a common ancestor
Analogous structures
structures similar in function but not structure (ex, bird and butterfly wings)
Population
the smallest unit able to evolve
Sources of variation
mutation and sexual reproduction
Five agents of evolutionary change
genetic drift (bottleneck, founder effect), gene flow (migration), mutation, non-random mating (sexual selection), selection
Bottleneck effect
a natural, random disaster reduces the population size and limits gene pool
Founder effect
a random group splinters off and starts a new colony
Heterozygote advantage
when the heterozygous genotype has a higher fitness than the homozygous individuals
Phylogeny
the history of the evolution of a species or group
Clade
a branch on a phylogenetic tree that includes a single common ancestor and all of its descendants
Derived traits
traits in the most recent ancestor
Synapomorphies
characteristics shared by a group due to their inheritance from a common ancestor
Convergent evolution
the independent evolution of similar features in species in a similar environment
Four sources of phylogenetic information
morphology, embryology/development, behavior, molecular data
Binomial nomenclature example
Homo Sapiens
Taxon
a group of populations that form a unit
Eight main taxonomic categories
domain, kingdom, phylum, class, order, family, genus, species
Speciation
the process in which populations evolve into their own distinct species
Biological species concept
a species is a population whose members can interbreed and produce fertile offspring
Ecological species concept
species occupy similar habitats
Morphological species concept
species have similar structure
Allopatric speciation
the formation of new species after geographic separation
Sympatric speciation
formation of new species in the same area
Pre-zygotic barriers
geographic isolation, ecological, temporal, behavioral, mechanical, gametic
Post-zygotic barriers
reduced hybrid viability, reduced hybrid fertility, hybrid breakdown
Haldane-Oparin hypothesis
early earth’s atmosphere was reducing and at first contained no organic molecules
Miller-Urey experiment
were able to form organic compounds out of the hypothesized conditions of early earth
Endosymbiosis theory
mitochondria and chloroplasts were once free-living cells
evidence: structural, genetic, functional
Non-polar covalent bonds
pair of valence electrons shared equally by 2 atoms (strong)
Polar covalent bonds
pair of valence electrons shared unequally by 2 atoms (strong)
Ionic bonds
one takes electrons and one gives electrons (weak)
Hydrogen bonds
attraction between positive hydrogen in one water molecule to negative oxygen in other water molecule
Five characteristics of water
- cohesion and adhesion
- water is a good solvent
- ice floats in liquid water
- water has a high specific heat
- water has a high heat of vaporization
Four main macromolecule classes
carbohydrates, lipids, nucleic acids, proteins
Dehydration synthesis
uses energy to make a polymer through the removal of water (condensation reaction/endergonic/anabolic)
Hydrolysis
releasing energy by splitting water and breaking polymer (digestion, exergonic, catabolic)
Starch
slow release of energy (used in plants)
Glycogen
fast release of energy (used in animals)
Glycosidic linkage
a covalent bond joining a carb to something else
Ester linkage
a bond between the oxygen and carbon atoms in lipids
Saturated fats
long straight chains, no carbon double bonds, solid at room temp, contributes to cardiovascular disease
Unsaturated fats
kinky chains, carbon doubles bonds, liquid at room temp
Components of a nucleotide
nitrogenous base, pentose sugar, phosphate group
Nucleic backbone
made of sugar and phosphate backbone, held together by phosphodiester bond
Components of an amino acid
central carbon, amino group, carboxyl group, R group (side chain)
Peptide bond
the bond between and amine (NH2) of one amino acid and the carboxyl (COOH) of another
Primary structure
the order of amino acids in the chain
Secondary structure
folding alone short sections of polypeptide (H bonds)
Tertiary structure
interactions between distant amino acids
Quaternary structure
more than one polypeptide chain bonded together
Protein denaturation
the unfolding of a protein (due to temp, pH, or salinity) that alters structure and destroys functionality
Enzyme concentration
as enzymes increase, reaction rate increases then levels off
Substrate concentration
as substrates increase reaction rate increases then levels off
Optimum temperature of enzymes
35-40 degrees C
Optimum pH of enzymes
6-8 but depends on local conditions
Competitive inhibtion
inhibitor and substrate compete for active site
Non-competitive inhibition
inhibitor binds to site other then active site (allosteric)
Feedback inhibition
final reaction product inhibits earlier step, stops unnecessary accumulation of product
Free ribosomes
ribosomes in the cytosol synthesize proteins in the cytosol
Bound ribosomes
ribosomes attached to ER synthesize proteins for export
Smooth ER
synthesizes lipids and hydrolyzes glycogen in the cytosol, builds membranes
Rough ER
produces proteins for export, packages into vesicles
Golgi apparatus
finishes, sorts, tags, and ships cell products in vesicles
Endomembrane system
nucleus, ribosomes, ER, golgi apparatus, vesicles
Lysosomes
only in animal cells, digests macromolecules, “cleans”
Vacuoles
storage in plants
Cytoskeleton
provides support and anchorage, motility, and regulation, made of microfilaments and microtubules
Phospholipid
hydrophilic head and hydrophobic tails
Peripheral proteins
loosely bound to the surface of membrane, usually as a cell surface identity marker
Transmembrane proteins
penetrate the lipid bilayer to allow for transport
Membrane carbohydrates
allow for cell to cell recognition
Second law of thermodynamics
the universe tends towards entropy
Hypertonic
more solute, less water
Hypotonic
less solute, more water
Isotonic
equal solute and water
Passive transport
diffusion of non-polar molecules from high to low
Active transport
diffusion from low to high, requires ATP
Phagocytosis
cellular eating
Pinocytosis
cellular drinking
Endocytosis
moving large molecules into a cell
Exocytosis
moving large molecules out of a cell
ATP
modified nucleotide that adds phosphate groups
Chemiosmosis
the movement of ions across a membrane (through ATP synthase) down their electrochemical gradient
Oxidation
losing electrons, exergonic (releases energy)
Reduction
gaining electrons, endergonic (stores energy)
Alcohol fermentation
irreversible anaerobic reaction converting pyruvate to ethanol and carbon dioxide
Lactic acid fermentation
reversible anaerobic reaction converting pyruvate to lactic acid
Glycolysis
first step of cellular respiration, occurs in the cytosol
Krebs/Citric acid cycle
second step of cellular respiration, occurs in mitochondrial matrix, net gain is 2 ATP and 10 electron carriers, happens twice for each glucose molecule
Electron transport chain (CR)
third step of cellular respiration, occurs in the inner mitochondrial membrane, along cristae
Substrate-level phosphorylation
the formation of ATP from inorganic molecules (Krebs and Glycolysis)
Oxidative-level phosphorylation
the formation of ATP in the presence of organic molecules (ex. oxygen in the ETC)
Stages of photosynthesis
Light-dependent reactions (mitochondria) and light-independent reactions (stroma)
Intercellular junctions in plants
plasmodesmata
Intercellular junctions in animals
tight junctions, gap junctions, and desmosomes
Autocrine
signal affects the same cell
Paracrine
signal affects nearby cells
Hormone (endocrine)
signal affects distant cells
Benefits of secondary messengers
Amplification, cascade multiplier, fast response
