VOCAB EXAM 2/Concepts

Protists

all eukaryotes except plants, animals, and fungi

Diplontic

multicellular stage is diploid (2N)

Haplontic

multicellular stage, if present, is haploid (1N)

Alternation of generations

both haploid and diploid multicellular stages

Diplontic Life Cycle

• Gametes are only 1N cells

• Fertilization produces 2N zygote

• zygote divides by mitosis to produce 2N multicellular organisms

• most animals, some protists

Haplontic Life Cycle

• Fertilized zygotes are only 2N cells, and immediately undergo meiosis

• Haploid cells divide by mitosis to produce clones or 1N multicellular organism

• Gametes produced by mitosis

• Most fungi, some protists

Alternation of generations Life cycle

• zygotes divide by mitosis to produce 2N multicellular sporophyte, which produces 1N spores by meiosis

• Spores divide by mitosis to produce 1N multicellular gametophyte, which produces 1N gametes by mitosis

• most plants, some protists

pellicle

protein bands underneath membrane

alveoli

flattened vesicles under plasma membrane

Coral bleaching

coral expel zooxanthellae when stressed

Sex

mixing of genetic information from two individuals

• usual process: meiosis followed by fertilization

reproducation

formation of new individuals

Conjugation

sex in ciliates

Process:

• Start and end with same 2 individuals

• each gets new genetic information

Phycoerythrin

gives them red color

Colonial

possible intermediate step to multicellularity

multicellular

isolated cells cannot survive alone

heterotrophs

• feed by ingestion and internal digestion

Embryonic development of animals

• zygote undergoes cleavage

• Blastula stage

• Gastrulation

cleavage

mitotic division without getting bigger

blastula stage

hollow ball of cells

gastrulation

cells from blastula wall move inward to form tissue layers

radial symmetry

• often sessile or drifting

• no left-right or front-back

bilateral symmetry

• usually move actively

• cephalization

cephalization

concentration of nerve tissue and sensory structures at front of body

differentiation

cells specialize during development

Diploblastic

• 2 layers

  • ectoderm —> outer covering

  • endoderm —> lining of gut

triploblastic

• 3 layers

  • ectoderm —> outer covering

  • mesoderm —> muscles, skeleton

  • endoderm —> lining of gut

Acoelomate

no cavity, just solid mesoderm tissue

pseudocoelomate

cavity in between mesoderm/endoderm

coelomate

cavity lined on all sides by mesoderm

Determinate cleavage

developmental fate of cells determined fate of cells determined early

indeterminate cleavage

each early cell can develop into complete organism

protosomes

“Mouth first”

blastopore —> mouth

deuterostomes

• “mouth second”

• Blastopore —> anus

segmentation (animals)

• repeated body units

• may be identical or specialized

Epidermis

• outer layer

• pores (ostia)

Choanocytes

• inner layer

• capture food, move water

Mesohyl

• gelationous matrix between cell layers

Gastrovascular cavity

incomplete gut with only one opening

polyp

sessile mouth/anus up

medusa

mobile, mouth/anus down

Mesoglea

gel in between

cnidocytes

epidermal cells specialized for prey capture

Nematocysts

cnidocytes with stinging toxins

Lophophore

• Ring of ciliated tentacles

• Found in ectoprocts and brachiopods

Trochophore

• planktonic larve with band of cilia

• found in colluscus and some annelids

Planarians

free living flatworms

Neodermata

parasitic flatworms

Corona

Crown of cilia

Mantle

Dorsal sheet of tissue; secretes shell

Mantle cavity

water-filled space; holds gills

Radula

Ribbon of teeth to scrape food

Open circulatory system

“Blood” empties into open space and directly contacts tissue

chromatophores

pigmented epithelial cells

parapodia

paddles on each segment

Chaetae

bristles made of chitin

Clitellum

secretes cocoon for reproduction

ecdysis

molting in order to grow

A Thin, flexible cuticle allows for?

• allows gas excgange

• restricted to damp habitats

A thick, strong cuticle?

• provides excellent protection

• requires jointed appendages for movement

Prokaryotes are… (2)

• bacteria

• archaea

eukaryotes are…

Eukarya

Prokaryotic cells

• no membrane-bound

• single circular chromosome

• divided by binary fission

Eukaryotic cells

• membrane-bound organelles

• multiple linear chromosomes

• divide by mitosis or meiosis

Prokaryote Morphology

• small

• unicellular, but may form colonies

• 3 basic shapes

  • Spherical —> cocci

  • rod-shaped —> Bacilli

  • spiral —> Spirilli

Prokaryote morphology inside the cell

• single circular chromosome in nucleoid region

• plasmids

• Prokaryotic ribosomes

• no organelles, but may have infoldings of plasma membrane

Prokaryote Morphology Cell boundaries

• most have rigid cell wall

• Bacterial cell walls made of peptidoglycan

• archaea cell walls not made of peptidoglycan

• archaea cell walls not made of peptidoglycan

• Two forms of bacterial cell walls, based on peptidoglycan thickness

• distinguished by gram staining

• may also have polysaccharide capsule

Prokaryote morphology external

• flagella for locomotion

• Fimbriae

• pili

Fimbriae

used for adhesion

pili

used to transfer DNA between cells

Endospores

• non-reproductive, dormant

• highly tolerant of environmental conditions

Binary fission

1. chromosome duplication

2. chromosome segregation

3. cell elongates

4. cell splits down the middle

Prokaryote Reproduction plasmids

• small separate pieces of DNA

• Reproduce independently

• can be passed to others

• can be inserted into or removed from main chromosome

• Rapid generation time

  • binary fission every 1-3 hours, or even faster

transformation

picking up DNA from enviroment

Transduction

getting DNA injected by a virus

Conjugation

getting DNA from another bacterium, through a pilus

Horizontal gene transfer (Sources of GV)

movement of DNA between individuals

• very common in prokaryotes

• occurs across species, and even across domains

Photoautotrophs

• energy from light, carbon from inorganic CO2

  • includes photosynthetic species

Photoheterotrophs

energy from light, but carbon from organic molecules made by other organisms

Chemoautotrophs

• energy from oxidizing inorganic compounds, carbon from inorganic source

  • nitrogen fixers

nitrogen fixers

convert atmospheric N2 gas into ammonia (NH3) usable by other organisms

Chemoheterotrophs

• energy and carbon from organic molecules

• most common across all groups

• herbivores, predators, decomposers, parasites

Obligate aerobes

• require presence of oxygen

• aerobic respiration

Obligate anaerobes

• require absence of oxygen

• anaerobic respiration (fermentation)

Facultative anaerobes

• can alternate, depending on environmental conditions

How can Horizontal gene transfer complicates phylogenetics?

• gene flow between unrelated lineages

• leads to genetic homoplasy

Importance of Prokaryotes

• key players in element cycling

• important in many symbiotic relationships

  • mutualism, commensalism, parasitim