midterm Flashcards
the 7 characteristics of life
display order, harness and utilize energy, reproduce, respond to stimuli, exhibit homeostasis, grow and develop, evolve
scientific method consists of what
- hypothesis 2. experiments and observations 3. analyzing the data 4. conclude- support or reject
how can substances penetrate the cell membrane?
through transport protein channels
what is the plasma membrane made of?
a bilayer of lipids(hydrophobic) embedded with protein molecules
what are the common shapes of prokaryotic cells?
cocci, bacilli, spirilla, square cells
what are the structural features of bacteria and archaea (prokaryotes)?
cell wall, DNA, ribosomes, flagella, pili
what does the plasma membrane do in prokaryotes?
metabolize food molecules in chemical energy (ATP)
what is the plasma membranes rigid external cell wall called?
glycocalyx— capsule
what does the flagella do?
how bacteria and archaea move, pushes cell through liquid medium
what are the pili made of and what do they do?
made of protein and attach bacterial cells to other cells as part of infection
what are plasmids and what do they do?
small circles of DNA, they replicate independently and provide bacteria with genetic advantages ex. antibiotic resistance
what are prokaryotic chromosomes?
single, circular DNA packaged into nucleoid
what are the 4 eukarya groups?
protists, fungi, plants, animals
what does the plasma membrane do in eukaryotic cells?
channel proteins for transport, receptors to bind molecules and trigger internal responses
what is a misconception about fungi?
that they are closely related to plants- they are more like animals
what are fungi?
heterotrophic eukaryotes that obtain carbon by breaking down organic molecules synthesized by other organisms
what are chloroplasts?
yellow-green plastids where photosynthesis takes place in plant cells
what are thylakoid membranes?
contain chlorophyll, a green pigment that absorbs light energy and converts it to chemical energy in photosynthesis
what are central vacuoles and what do they do?
large vesicles that store salts, organic acids, sugars, storage proteins, pigments, and sometimes waste products. they also contain enzymes that break down molecules and have molecules that provide chemical defences
what are cell walls made of and what do they do in plant cells?
made of cellulose fibres that provide tensile strength. they support cells, contain pressure from vacuole and protect cells from bacteria and fungi
what are photoautotrophs?
use light from the sun (energy) and inorganic materials (CO2 and H2O) for photosynthesis
what are chemoautotrophs?
use inorganic compounds (H gas, S, NH3, nitrites, Fe) as energy sources for chemosynthesis
what are heterotrophs?
use energy in organic matter obtained from other organisms
what are photoheterotrophs?
use light from sun to generate ATP but need to take in organic compounds from their environment like alcohol or fatty acids ex. halobacterium
what are chemoheterotrophs?
must obtain organic compounds for both energy and as a carbon source ex. bacteria
what is photosynthesis?
the use of light energy to convert CO2 into an organic form
which photosynthetic organisms are the primary producers of earth?
photoautotrophs
which domains are photosynthesis present in?
bacteria and eukarya NOT archaea
what are autotrophs?
organisms that make required organic molecules from inorganic sources (CO2 and water)
what are photoautotrophs?
autotrophs that use light as the energy source to make organic molecules by photosynthesis ex. bacteria, protists, and plants
what are chemoautotrophs?
autotrophs that use compounds such as hydrogen sulfide and ferrus irons as a source of energy ex. bacteria and archaea, NO eukaryotes
why are all animals heterotrophs?
they obtain carbon from organic molecules, living hosts, wastes, or remains of dead organisms
what is metabolism?
the collection of all chemical reactions present within a cell or organism
what is an anabolic pathway?
a series of reactions that results in the synthesis of larger and more complex molecules from simpler molecules ex. biosynthesis of carbs, proteins, and nucleic acids
what is a catabolic pathway?
a series of chemical reactions that results in the breakdown of larger, more complex molecules into smaller less complex one ex. cellular respiration - energy rich food molecules are converted into simpler and lower energy molecules
how are catabolic and anabolic pathways linked?
through chemical energy (ATP, NADH, NADPH)
what’s an ATP?
specific form of chemical energy that links the catabolic and anabolic pathways
what is ATP hydrolysis?
provides free energy and can be used as a source of energy for the cell as a result of its reaction with water
what are the advantages and disadvantages of asexual reproduction?
large number of offspring produced quickly, only 1 individual required… no genetic variation
what are the advantages and disadvantages of sexual reproduction?
increase genetic variation, enhance reproductive success in changing environments… locate a mate
what are the types of asexual reproduction involving mitosis?
fission, budding, and fragmentation
what is parthenogenesis?
asexual reproduction where females produce eggs that develop without being fertilized
how does the amoeba reproduce?
extends its pseudopodia where the cytoplasm and nucleus flow into, multiple fission in unfavourable conditions and binary fission in favourable conditions
what creatures use parthenogenesis to reproduce?
fish, reptiles, scorpions, mites, bees, never in mammals
what is apomixis?
asexual reproduction in plants without egg fertilization ex. dandelions
what is a hermaphrodite?
a sexually reproducing organism that produces both male and female gametes
what is conjugation?
2 organisms fuse along a common surface (bridge/connection) and exchange genetic material, no increase in number of individuals ex. paramecium, spirogyra
how do daphnia reproduce?
cyclic reproduction, alternate between sexual and asexual reproduction
how do paramecium reproduce?
binary fission or conjugation (in stress)
what is homeostasis?
a self-regulating process where a living organism can maintain internal stability while adjusting to changing external environments, a dynamic process to change internal conditions in order to survive external conditions
what is thermoregulation?
a dynamic, homeostatic interaction between an organisms internal processes and it’s external environment, to maintain a stable, physiological temp.
what are the differences in metabolic responses of ectotherms and endotherms?
endotherms metabolic rate rises at low temps generating extra body heat, ectotherms metabolic rate falls at low temps conserving energy. the metabolic rates of endotherms are always higher
what’s an ectotherm and example?
they obtain heat energy externally by regulating heat exchange with the environment and using a combo of behavioural and heat-generating physiological mechanisms ex. most aquatic invertebrates
how are fish ectotherms?
use behavioural mechanisms to regulate temp.
how are amphibians and reptiles ectotherms?
body temps closely match environmental temps and can move to different locations to regulate
what are endotherms?
obtain heat energy from internal reactions, balance internal heat production against heat loss from body surface, internal heat production is controlled by negative feedback pathways triggered by thermoreceptors and integrated by hypothalamus ex. mammals and birds
how does heat flow between animals and the environment?
conduction, convection, radiation, and evaporation
how does a husky conserve heat?
by curling up with limbs under body and tail around nose
how do penguins conserve energy?
by huddling together
what is a virus?
a toxin or poison, smaller than a bacterium
what are characteristics of viruses?
non living, non cellular, wide range of shapes and sizes, no organelles, made of genetic material (nucleic acid, DNA or RNA), contained within a protective protein coat called a capsid, surrounded by a lipid bilayer, unable to replicate outside of a living system
what are the 2 basic structural forms of viruses?
helical (infect plant cells) or polyhedral
what does viruses rely on hosts for?
reproduction and essential metabolic processes
what are viroids and what are they made of?
plant pathogens that consist of small pieces of circular RNA, no cellular structure, depend upon enzymes of plant host for replication, RNA of viroids do not code for any proteins
what are prions?
protein molecules that cause degenerative diseases of mammalian nervous systems, non living, simpler than viruses, no cellular structure, lack hereditary material ( no DNA or RNA)
what is Creutzfeldt-Jakob disease?
a fatal human neurodegenerative condition cause by prions, contracted by eating beef from cows with BSE (mad cow disease), folding in normal protein molecules, brain full of holes (sponge)
what is the morphological species concept and what is it used for?
it is the idea that all individuals of a species share measurable traits that distinguish them from individuals of other species, used to identify the species of fossilized organisms
what is the scientific name of human species?
homo sapiens sapiens
what is the biological species concept?
groups of interbreeding natural populations reproductively isolated from other groups, if members of 2 populations interbreed under natural conditions they belong to the same species
what is the phylogenetic species concept?
uses morphological and genetic sequence data, comprises populations that share a recent evolutionary history, can be applied to extinct species and species that reproduce asexually
what are subspecies?
geographically separated populations of a species have dramatic phenotypic variations, usually interbred
what are the 3 levels of biodiversity?
ecosystem diversity (habitat), species diversity (# of species and individuals of each species), genetic diversity (genetic variability)
what is taxonomy?
theory and practice of classifying organisms into taxa within a hierarchy
what is nomenclature?
process where scientific names are produced for taxa to provide a common ground
what is phylogenetics?
story of the evolutionary history or relationships of organisms
what are systematics and systematists?
a branch of bio that studies the diversity of life and it’s evolutionary relationships, the scientists that identify, name, and classify organisms
what is the scala naturae (scale of nature)?
a ladder of living organisms (plants and animals) classified based on the complexity, vitality, and ability to move, as well as modes of transportation (air, land, water)
what is the system of binomial nomenclature?
species are assigned a latinized 2 part name or binomial, first part is a Genus (similar characteristics), second part is the species name (lowercase). entire scientific name is always italicized
what are phylogenetic trees?
hypotheses that identify likely relationships among species and taxonomic groups and portray the branching pattern of evolution
what are the parts of a phylogenetic tree?
root (common ancestor), lineages (sequence of biological entities), cladogenesis (an evolutionary splitting of a parent species into 2 species forms a clade), clade (a group of organisms evolved from common ancestor), sister clades (2 lineages that share a node), node (branch points)
what has the largest number and variety of prokaryotes?
domain bacteria (52 phyla represent 50 kingdoms) and occur worldwide
what is gram negative bacteria?
outer membrane of cell wall made of lipopolysaccharides, phospholipids, and proteins. thin layer of peptidoglycan does not retain violet when exposed to alcohol wash instead it’s pink or red
what is gram positive bacteria?
thick layer of peptidoglycan in cell wall stains bacteria a deep violet colour
what are methanogens?
archaea that live in swamps, low O2 habitats, and intestines of humans and animals
what are extremophiles?
archaea that live in extreme and harsh environments ex. hot springs
what are halophiles?
species that occupy habitats of high salt content ex. halobacterium
what are acidophiles?
species that occupy habitats of low pH levels
what are hyperthermophiles?
species that occupy habitats of high temps.
what are psychophiles?
species that occupy habitats of low temps. (conditions that kill most bacteria and eukaryotes)
what are the 4 kingdoms of eukarya?
protista, plantae, fungi, animalia
what are the traits of protista?
unicellular protozoans and unicellular and multicellular algae- wide range of habitats, great range of complexity, some have cell walls, not all have chloroplasts
how do protists move?
cilia, flagella, or pseudopods (amoeba)
what are chlorophyta and examples
green algae - inhabitants of marine and fresh water environments ex. chlamydomonas (unicellular), spirogyra (multicellular)
what are charophyta and examples
green algae - live in freshwater, land plants evolved from charophytes ex. micrasterias (unicellular), chara (multicellular)
what is sporopollenin?
a molecule that forms a protective barrier that prevents closed structures (zygotes, spores) from desiccation
land plants evolved from charophytes based on what 3 criteria?
1) similar structure of motile sperm to those in land plants with flagellated sperm 2) similar cell wall producing events during cell division 3) presence of sporopollenin in charophyte zygotes and land plant spores
what are the traits of plantae?
multicellular, photosynthetic, cell walls (cellulose)- most lane plants don’t move gametes might move using cilia or flagella, organelles include chloroplasts
what are plants sexual life cycle?
they alternate between multicellular gamete producing gametophyte generation (n chromosomes) and multicellular spore forming sporophyte generation (2n chromosomes)
what are non vascular plants and examples
gametophyte stage dominant, have thin cuticle and stomata, no roots or leaves ex. liverworts, mosses, hornworts
what are vascular plants that lack seeds and examples
sporophyte stage dominant typically grows much larger than non vascular plants, have lignified vascular tissues(transport water and nutrients to help growth provide structural support) have true roots and leaves ex. club mosses, ferns and horsetails
what are vascular seed plants and examples
sporophyte stage dominant, adapted to life on land, microscopic gametophytes protected against drying out. males enclosed in pollen grains, female in ovules. gametophyte stage reduced to a few cells ex. angiosperms, gymnosperms
what is vascular tissue?
conducting tissues: xylem transports water and dissolved minerals, and phloem transports sugars
what is a seed?
the mature state of an ovule after fertilization, resulting from pollination and fertilization in spermatophytes. contains the plant embryo, nutrient source, and protective cover
what are gymnosperms?
dominant plant of forests, lack fruit and flowers, “naked seed”, seeds derived from ovary, or from modified leaves which form cones
what are angiosperms?
“container” plants with enclosed seeds (inside fruit), flowers enable dispersal of male gametes by attracting pollinators, have vascular systems for transporting water and nutrients, large leaves for maximizing photosynthesis
what are the traits of fungi and examples
multicellular, hetertrophic, cell walls (chitin), no chloroplasts, no mechanism to move, ex. mushrooms, molds, fungi
what is chytridomycota and example
spores of these fungi have flagella and certain species are decimating frog populations ex. allomyces (water mold)
what is zygomycota and example
fruiting bodies of these fungi can stand extreme conditions, becoming metabolically inactive to avoid death in freezing/dehydrating conditions ex. rhizopus (bread mold)
what are ascomycota and example
most species in this group form conidia ex. sordaria (plant saprobe)
what are basidiomycota and example
these fungi form club-like fruiting bodies ex. agaricus (mushroom)
how do fungi obtain nutrients?
by absorption, extra cellular digestion, some use enzymes to digest large molecules directly (break down into simple compounds), some use enzymes to break through cell walls of other organisms allowing them access to that cell’s nutrients
how do saprophytic fungi get nutrients?
grow on dead organic materials like moist wood, leather, rotten fruit and veggies, cheese, rotting leaves, and moist bread
how do parasitic fungi get nutrients?
absorb organic material from living tissues of hosts they parasitize, harmful to their host and cause diseases on crops
how do predacious fungi obtain nutrients?
use a rapidly constricting ring around a nematode to hold it captive, hyphae sinks its tips into the body of the victim
how do mutualistic fungi obtain nutrients?
photosynthesis
what are the traits of animalia?
multicellular animals, no cell walls, no chloroplasts or photosynthetic pigments, heterotrophic, move with cilia, flagella, or muscular organs
what is the most successful animal group and why?
arthropods because they are the most diverse group (# of species) and are adapted for all different environments (air, desert, marine, freshwater, etc.)
what is adaptation?
the inherited aspects of an individual that make it better suited to a particular environment
what is fitness?
an individual’s reproductive success, the more surviving offspring the higher the fitness, a trait is only adaptive if it increases fitness
what are mutations?
random, heritable changes in the DNA sequence, can come from errors in DNA replication
what are the traits of cyanobacteria?
eukaryotic, photosynthetic, unicellular or multicellular, filamentous, found in aquatic environments, autotrophs, contain chloroplasts
