POB Final Exam - Shadwick

who is the father of microbiology?

Antonie van Leeuwenhoek

who proved microbes cause diseases and how to develop methods to control them?

Louis Pasteur

microbiota

all the microorganisms that live in or on a specific environment

what are some beneficial effects of microbes??

• they help with digestion

• produce vitamins

• protect against pathogens

• recycle nutrients

chemical evolution vs. biological evolution

chemical: life before cells existed, no reproduction involved

biological: life after cells existed, populations change over generations, driven by mutation + natural selection

1st stage of formation of cells

organic monomers - evolution of monomers, Primoridal soup

stage 2 of formation of cells

organic polymers - evolution of polymers

stage 3 of formation of cells

protobionts - evolution of protobionts

stage 4 of cell formation

living cells - evolution of living cells

Miller-Urey experiment (1953)

simulated earth’s early atmospheric conditions to show how organic monomers could have formed naturally

Archaea

- small, genome is a single, closed, circular, DNA molecule

- plasma membrane single lipid layer with branched side chains

- 3 main types are based on unique habitats and metabolism

bacteria (domain bacteria)

- most common type of prokaryote on Earth

- bacteria have 3 basic shapes: rod, spherical, & spiral-shaped

ways to distinguish between archaea, bacteria, and eukaryotes

archaea - have no nucleus

bacteria - have unbranched fatty acids

eukaryotes - have a nucleus, large and complex cells

halophiles

salty habitats that are isolated from environments

examples: the Great Salt Lake, the Dead Sea, and hypersaline soils

thermoacidophiles

extremely hot, acidic, aquatic environments evolved to function at temperatures as high as 80 degrees Celsius

examples: hot springs, geysers, and underwater volcanoes

methanogens

- use carbon dioxide and hydrogen as energy sources

- produce methane as a byproduct

- in anaerobic environments like swamps, and intestines of animals

examples: cows and other animals, including humans

3 shapes of bacteria

rod, spherical, and spiral-shaped

rod = bacillus

spherical = cocci

spiral-shaped = spirillum

bacteria reproduction

- the bacterial cell replicates its genome and divides into two new daughter cells

- bacteria reproduction is asexual, by binary fission

the 3 ways bacteria can increase their genetic variation

conjugation: donor cell passes DNA to a recipient call by way of a sex pilus

transformation: bacterium takes up DNA from environment released by dead bacteria

transduction: viruses carry bacterial DNA from cell to cell

functions of cyanobacteria

metabolism:

• they perform photosynthesis / use sunlight, water, and CO2 to make glucose

ecological: as a result of the photosynthesis, they release oxygen for other organisms as a producer

4 diseases caused by Streptococcus pyrogenes

strep throat (Pharyngitis): sore throat, fever, swollen tonsils

impetigo (in infants): mild skin disease with honey-colored crusts

scarlet fever: produces a red rash

rheumatic fever: auto-immune after strep throat

diseases caused by Staphylococcus aureus

skin infections: boils, impetigo, etc.

MRSA: a strain resistant to methicillin that kills young, healthy individuals

two types of food poisoning

• food poisoning producing toxins while growing in food

  • ex) clostridium botulinum

• food poisoning that causes an infection while growing in the intestines

  • ex) salmonella

antibiotics

inhibit bacteria by interfering with bacterial pathways

2 functions of most antibiotics

1. inhibit protein synthesis by bacteria

   1. example: erythromycin

2. inhibit cell wall biosynthesis

   1. example: penicillin

viruses

- acellular structures that are parasites

- use the host cell's components, such as ribosomes and certain enzymes

prions

- infect protein particles

- normal proteins change their shape

viral reproduction stages

“AERBAB”

1) Attachment: spike combines with the receptor

2) Entry: virus enters host cell and uncoating occurs

3) Replication: viral DNA is replicated

4) Biosynthesis: viral components are synthesized

5) Assembly: new viruses are now present

6) Budding: virus acquires an envelope and spikes

antigenic drift

a gradual change caused by small genetic mutations, occurring in RNA genomes

• not many changes

antigenic shift

a sudden + major change in antigens due to the reassortment of DNA segments of two different strains of a virus infecting the same host cell

prion diseases and who they affect

Bovine spongiform encephalopathy ("mad cow disease")

- it affects cattle

Chronic wasting disease

- affects deer, elk and moose

evolution and characteristics of the first eukaryotic cells

characteristics:

• had a nucleus with a nuclear membrane

• internal cytoskeleton

• membrane-bound organelles

evolution: endosymbiotic theory

• a prokaryotic cell engulfed a bacterial cell

5 protists characteristics

- are eukaryotes that are not plants, animals, or fungi

- very diverse

- many unicellular

- have meiosis and genders

- have mitochondria

4 ways protists obtain food and energy?

- through photoautotrophs, called algae, producing their food by photosynthesis

- through heterotrophs, called protozoans, eating bacteria and other protists

- through heterotrophs, called parasites, derive their nutrition from a living host, who is harmed by the interaction

- through mixotrophs, using photosynthesis and heterotrophy

Archaeplastids examples

land plants, green algae, red algae, spirogyra

what are 4 chromalveolates

brown algae, diatoms, ciliates, dinoflagellates

Excavates

heterotrophic protozoans that propel themselves through one or more flagella

• ex) euglenids

Amoebozoan examples

amoeboids and plasmodial slime molds

Opisthokonts

animals, fungi, and certain flagellates

5 spirogyra characteristics

- an archaeplastid

- filamentous green alga

- has chloroplast

- sexual reproduction by conjugation

- cell walls connect by a tube and haploid cells fuse

3 diatom characteristics

- unicellular algae

- do 20 to 25% of photosynthesis on Earth

- glassy cell wall containing silica

brown algae

- multicellular and marine

- brown because of pigments

- include kelp

- primary producers for diverse and productive community

dinoflagellates

- unicellular algae

- cause "blooms" in polluted coastal waters

ciliates

- unicellular protists including heterotrophs

- named for their use of cilia to move and to sweep food into their mouth

euglena

- has a flagellum

- performs photosynthesis

- mixotrophic (can photosynthesize and absorb food from the environment)

- has an eyespot for detecting light intensity

amoeba

- organisms with pseudopodia

- feeds from phagocytosis

plasmodial slime molds

- a single cell

- large and multinucleate

- feed on decomposers on dead plant matter

sac fungi (phylum Ascomycota)

- named after cup-like sexual reproductive structure, the ascocarp

- many sac fungi reproduce by producing chains of asexual spores called conidia

examples: yeasts, truffles, penicillium

yeasts

- unicellular fungi, many are sac fungi

- produce bread, wine, beer

club fungi (Phylum Basidiomycota)

- produce spores on club-shaped structures called basidium

- they use basidium to reproduce

examples: mushrooms, smuts, bracket fungi

lichens

- efficient at acquiring nutrients and moisture

- primary colonizers because they produce organic matter and soil that supports plants

mycorrhizae

mutualistic relationships with plant roots

- allow plants to grow more successfully in poor soils

challenges of plants moving from a watery environment onto land

- gametes, zygotes and embryos must be kept moist

- must obtain and move water throughout body

what 3 characteristics do plants and green algae share?

- chlorophyll A and B

- store carbohydrates as starch

- have cellulose in cell walls

the 5 major evolutionary events

1. development of embryo protection

2. development of vascular tissue (to get taller)

3. development of megaphylls (large leaves with branching veins)

4. development of seeds

5. development of flowers and fruit

Alternation of Generations Life Cycle

- plants have a life cycle that with alternation of generations

- two multicellular individuals alternate, each producing the other

- Sporophyte (2n or diploid)

- produces spores by meiosis

- gametophyte (n or haploid)

- produces gametes by meiosis

- a sperm and egg fuse, forming a diploid zygote

nonvascular plants - mosses

- no vascular tissue and no seeds

- small

- live mostly in moist areas

- the gametophyte generation is dominant

- flagellated sperm swim to the egg

- sporophyte relies totally on parent plant

seedless vascular plants - ferns and lycophytes

- vascular plants have true roots, stems and leaves

roots: absorb water and minerals from the soil

stems: conduct water to the leaves

leaves: photosynthesis and gas exchange

ferns (phylum Polypodiophyta)

- sporophyte dominant

- fronds grow from horizontal stem

- spores often found on bottom of frond

- fronds are megaphylls

lycophytes

- also called club mosses

- among first land plants with vascular tissue

- upright stems

- small leaves called microphylls with single vein

- sporangia borne on clusters of leaves

gymnosperms ("naked seeds")

- most are cone-bearing

- ovules located on surfaces of their cone scales

- no enclosing tissue around seeds

conifers (phylum Pinophyta)

-gymnosperms

- adapted to cold, dry weather

- needle-like leaves conserve water with thick cuticle

- pollen cones and seed cones

gingkoes (phylum Ginkgophyta)

- only one species survives.. Gingko biloba

- female trees produce bad smelling seeds

- male trees are preferred for ornamental planting

- gingkoes are resistant to pollution and disease

angiosperms

- seeds develop from an ovule within an ovary (the vessel

- ovary becomes the fruit

- produce covered seeds (not naked)

animal pollinators

- animal pollinated flowers usually have showy petals or strong fragrance

- bees and other insects, bats, birds

wind pollinators

- wind pollinated flowers usually lack showy petals

- grasses, oaks, hickory

fruit to seed distribution

dry fruit can break open to scatter seeds, have wind blown fruit, or attach to animals

the parts of seeds and the evolutionary advantages that they have

embryo with a nutrient supply that allows them to survive harsh conditions while also giving them reproductive advantages over single-celled spores

characteristics that all animals share

- multicellular eukaryotes

- locomotion with muscle fibers

- ingestion of food

- diploid adult with sexual reproduction, only gametes are haploid

- zygote divides in mitosis and creates a ball of cells called a blastula

- embryonic development

asymmetrical

- no particular symmetry

example: sponges

radial symmetry

- circular organization; many longitudinal slices will produce mirror images

bilateral symmetry

definite right and left halves - only one longitudinal cut down midline produces mirror images

- bilaterally symmetric animals show cephalization (brain and sense organs at anterior)

levels of organization

cellular

- no true tissues

- sponges

tissue

- have 2 of 3 germ layers: ectoderm and endoderm

- cnidarians like hydra

organ

- have all 3 germ layers: ectoderm, endoderm, and mesoderm (triploblastic)

- majority of animals

deuterostomes

the blastopore becomes the anus; the mouth forms second

protostomes

the blastopore (first opening in the embryo) becomes the mouth

sponges - asymetry (phylum Porifera)

- cellular level or organization

- sac-like body with many pores

- multicellular, but lack organized tissues

- filter feeders; filter water for food

- choanocytes: flagellated cells

- spongin: proteinaceous skeleton

cnidarians- radial symmetry

- have true tissues

- all aquatic

- named for cnidocytes, specialized stinging cells contain nematocysts

examples: hydra, anemones, corals, and jellyfish

contrast sponges and cnidarians

sponges lack true tissues and cnidarians have true tissues, which is their stinging cells

flatworms (Phylum Platyhlminthes)

- incomplete digestive tract with one opening (mouth)

- no body cavity

- free-living planarians

- have muscles and excretory, reproductive, and digestive systems

- parasitic flukes and tapeworms

planarians

- freshwater

- eyespots

- feed on small organisms

tapeworms

- parasitic

- live inside the intestines of vertebrate hosts

- have no digestive system

molluscs

3 basic characteristics:

1. visceral mass: includes most organs

2. foot: muscular portion used for locomotion

3. mantle: covering that almost encloses visceral mass

extra: radula - rasping organ for feeding

gastropods

- foot is flattened ventrally

- move by muscle contractions along the foot

- some are herbivores, others carnivores

- existence of shell varies

examples: conchs and snails

cephalopods

- foot has evolved into funnel or siphon

- powerful beak and radula used for feeding

- cephalization is apparent

examples: squids, octopus, nautilus

bivalves

- 2 part shells composed of protein and calcium carbonate are secreted by male

- gills located within the mantle cavity, used for gas exchange

- filter feeders: water enters through incurrent siphon

examples: clams, oysters, scallops, mussels

annelids (phylum Annelida)

- segmented; visible rings encircling outside body

- no internal or external skeleton

- hydrostatic skeleton: a fluid filled interior that support muscle contraction

- enhances flexibility

- each body segment moves independently

- locomotion by contraction and expansion of each body segment

arthropods (phylum Arthropoda)

3 basic characteristics:

- exoskeleton

- segmented body

- jointed appendages (legs, antennae and mouthparts with joints that allow complex, flexible movement)

crustaceans (subphylum Crustacea)

- largely marine arthropods

- some freshwater, including crayfish

- some terrestrial, including sowbug or pillbug

- named for their hard exoskeleton

insects (subphylum Uniramia)

- body is divided into 3 regions:

head - sensory antennae, compound or simple eyes / mouthparts adapted to each insect's way of life

abdomen - contains most internal organs

thorax - 3 pairs of legs and wings, if present / wings provide certain advantages

examples of advantages: escape from predators, mating, and finding food

arachnids (suphylum Chelicerata)

examples: scorpions, spiders, ticks, and mites

- cephalothorax has 6 pairs of appendages: chelicerae, pedipalps, and 4 pairs of walking legs

- abdomen contains internal organs

echinoderms

- diverse group of marine animals

- endoskeleton made of calcium-rich plates

- named for spines sticking out of their skin

- lack features associated with vertebrates

sea star (starfish)

- is an echinoderm

- 5 rayed body with mouth on underside (oral) and anus on upper side (aboral)

4 characteristics that all chordates share at some point in their life cycle

notochord: dorsal supporting rod, replaced by vertebral column during development in vertebrates

dorsal tubular nerve cord: nerve cord containing a fluid-filled canal

pharyngeal pouches: final development depends on the adult chordate

postanal tail: extends beyond the anus

lancelets

- live in shallow coastal waters

- retain all 4 chordate characteristics as an adult

- filter feeder

phylogenetic tree practice:

jawless fish

- cylindrical body shape with smooth, scaleless skin

- no jaws or paired fins

- scavengers

- extreme slime defense

example in picture: hagfish

jawed fish

- have jaws

- have paired fins

- may have cartilage or bone skeletons

examples: sharks rays and all bony fishes

major evolutionary innovations distinguishing fish from amphibians

- lungs for breathing air

- fleshy appendages; could be adapted for locomotion on land

frogs and toads

- no tails as adults

- long, powerful hind legs for jumping

- typically vocal; many have distinct mating calls

salamanders and newts

- longs bodies with tails

- four legs of similar size

- most have regeneration