Biology 150 final

cumulative

4 steps of the origins of life

1. formation of organic molecules (reducing atmosphere hypothesis, deep sea vent hypothesis, extraterrestrial hypothesis)

2. transformation of simple organic molecules into complex molecules (likely aided by mineral surfaces like clay that catalyze polymerization)

3. becoming cellular structures, separating internal from external (protobiont)

4. gaining chemical activity (RNA thought to be the first macromolecule in protobionts bc it can self-reproduce, catalyze, and store info

Miller-Urey experiment

Miller-Urey wanted to see if organic molecules could have formed in prebiotic conditions. They had O2, H2O, CH4, and NH3 in a thing that replicated prebiotic conditions and they waited to see if organic molecules would form in those conditions. They found that organic molecules were formed in those environments.

Fossil dating

technique used to determine specimen age by measuring percentage of radioisotope decay, igenous rocks

Evidence of evolution

• homologies

• selective breeding

• fossils

• vestigial structures

• convergent evolution

what are homologs

features in different species that come from a shared common ancestor

paralogs vs orthologs

both homologs (genes come from common ancestor) but differ in how they evolved. Paralogs evolved via a gene duplication event and orthologs evolved through a speciation event

mechanisms of reproductive isolation

pre-zygotic - temporal isolation (awake at different times), geographic isolation (live in different places), behavioral isolation (having different sexual mating calls), gametic isolation (can have sex but cannot reproduce), mechanical isolation (physically cannot reproduce i.e. having diff genetalia)

post zygotic - hybrid insterility (can reproduce but the offspring is infertile) or hybrid inviability (zygote becomes inviable post fertilization)

speciation

evolutionary process in which populations evolve to become distinct species

bacterial vs archeal cell membranes

unbranched, ester bonded, D-glycerol, fatty acid chain = bacterial

branched, ether bonded, L-glycerol, isoprene chain = archeal

Horizontal gene transfer and mechanisms by which it occurs

Gram positive vs gram negative bacteria

have peptidoglycan layer with no envelope, purple in color (gram positive)

thinner peptidoglycan layer with outer envelope, Pink in color (gram negative)

Definition of protists

eukaryotes that don’t fit in animal plant or fungi kingdoms, can be uni or multicellular, like moist habitats, labelled by their ecological roles and motility

List Eukaryotic supergroups as covered in class

1. discoba

2. land plants and relatives

3. alveolata

4. stramenopila

5. rhizaria

6. ameobozoa

7. opsithokonta

Fungal phylogenetic tree

Plant phylogenetic tree

Alternation of generations (gametophyte and sporophyte stages and prominence in lifecycles)

Flower parts, perfect/imperfect flowers, incomplete/complete flowers

Monoecious vs dioecious plants

Angiosperm reproduction

Double fertilization

2 distinct fertilization events

Mycorrhizae and symbioses

Nitrogen fixing

Domains of life

importance of plant transport

for plant - growth, behavior, nutrition

for earth - climate, water cycle

difference between active and passive transport

passive doesnt use energy and active does

types of passive transport

passive diffusion - moves across membrane via concentration gradient

facilitated diffusion - protein in membrane moves it across membrane along gradient

aquaporins - facilitated diffusion of water

types of active transport

1 active transport - requires ATP, moves against gradient

2 active transport - ATP used to pump ions against gradient (H+ or NO3)

symporters - transports 2 substances in same direction across membrane

what type of transport do plants mainly use

active transport (bringing water and minerals up)

difference between hypotonic, hypertonic, and isotonic

hypotonic - lower solute outside the cell rather than inside

hypertonic - lower solute inside the cell rather than outside

isotonic - equal solute concentration inside and outside

how does a cell react in different solute concentrations

in hypotonic the cell becomes turgid (plasma membrane presses tightly against cell wall)

in hypertonic the cell becomes plasmolyzed (so much water loss that the membrane contorts away from wall)

in isotonic the cell becomes flaccid (the plasma membrane does not press tightly against cell wall)

water potential

tendency of water to move, moves from high to low potential

what are different adaptations to osmotic stress

osmotic adjustment - higher solute concentration of cytosol, lower water potential = water moves in

desiccation tolerance - sugars in cytosol bind to membrane = stabilization

halophytes - prevents water loss, increase inorganic salts in vacuoles, some excrete salt.

what is a symplast

continuum of cytosol linked by plasmodesmata

what is an apoplast

water-filled cell walls and intercellular spaces

what is symplastic

when molecules move to cytosol of an adjacent cell through plasmodesmata

what is apoplastic

when molecules move in water-filled cell walls and intercellular spaces

what is transmembrane

when molecules are exported out of 1 cell via membrane proteins and taken up by an adjacent cell

where does apoplastic stop

root endodermis

what is the casparian strip

creates a barrier to harmful chemicals so they don’t spread throughout the plant and kill the xylem

what is a process of long-distance transport and define it

bulk flow: mass movement of liquid by pressure, gravity, or both

xylem general information

has tracheary elements: tracheids & vessel elements

developement: 2nd wall deposited inside 1st wall, 2 wall is rich in lignin

lignin: for strength, durability, and water proofing

what are tracheids

long and narrow, usually slanted end walls, long tubes that fit together, end walls and pits are not lignified

what happens to tissues expand in the tracheids

the lignin starts spiraling

vessel elements

have pits inside walls, perforated end walls, lignified 2nd walls

what kind of plant are vessel elements located in

mainly angiosperms not gymnosperms

are vessel elements more efficient than tracheids and why

vessel elements because they have larger diameter which is better for bulk flow and the perforated end walls allows for faster flow

what is guttation and what causes it

when drops of liquid form outside plant due to root pressure

what is transpiration and when does it happen

the movement of water out the leaf via stomata, occurs when leaf is exposed to drier air

cohesion

water molecules sticking together, allows for continuous movement within the xylem

tension

when water evaporates surface tension increases in the intercellular spaces of cells

what are adaptations to water loss

waxy cuticles

stomatal opening and closing

leaf abscission - process of leaf shedding

how do organic molecules transport in phloem

• sieve tube elements

• companion cells

phloem parts

supporting fibers

parenchyma cells

sieve tube elements

companion cells

sieve tube elements

lost most cytoplasm and nucleus, arranged end to end

mature sieve tube elements

retains only peripheral cytoplasm, some ER, mitochondria, and plastids

sieve plates

perpherated end walls of mature sieve elements (perpherations are called sieve plate pores)

companion cells

support systems, provides mRNA and proteins to sieve tube elements

what is phloem loading

sugars move to companion cells or sieve tube elements via plasmodesmata

pressure flow hypothesis (phloem transport)

sugars load into phloem causes water to enter by bulk flow from xylem, water entry increases pressure causing sap to flow, accumulation of sugar reduces solute concentration resulting in bulk water flow into xylem and then water from xylem goes up via transpiration

behavior

response to stimulus (can be either external or internal)

examples of internal stimuli

plants produce chemical signals and hormones

examples of external stimuli

touch, wind, temp, gravity, soil, herbivores, symbionts, pathogens

trophism

growth in specific direction, dependent on stimulus (plant grows towards sun)

how does stimuli lead to behavioral activation

receptor molecules recieve signals and become activated, second messengers can be produced that transmit those signals to effector proteins, effector proteins affect gene expression or other cellular processes that can influence the plants behavior/development

Auxin function

establishes apical basil polarity, induces vascular tissue development, mediates phototropism, promotes formation of roots, inhibits leaf and fruit drops, stimulates fruit development

cytokinins function

promotes cell division, influences cell specialization and cell aging, activates secondary meristem developement, promotes root growth, promotes shoot development

gibberellins

stimulates cell division and cell elongation, stimulates stem elongation and flowering, promotes seed germination

abscisic acid

slows or stops metabolism during environmental stress, induces bud and seed dormancy, prevents seed germination in unfavorable conditions, promotes stomatal closing

how does auxin work in the cell

diffuses into cell as uncharged form or as an anion through auxin influx carrier, exits cell as an anion through auxin efflux carriers, locations of the auxin proteins determines the direction of the auxin flow

forms of auxin and what they are

IAAH: uncharged form

IAA-: charged form

AUX1: auxin influx carrier

PINS: auxin efflux carrier

hormones that deal with environmental stress

ABA, salicylic acid, systemic, jasmonic acid, NO

what is ABA

stops metabolism when conditions are poor, prevents seed germination and induces seed and bud dormancy

photoperiodism

ability to measure and respond to light amounts and day lengths

types of photoreceptors

blue light —> phototropins and cryptochromes

red light —> phytochromes

phytochromes

ASK FOR HELP

how do plants protect from herbivores

when mouth secretions from herbivores and tissue damage induce production of toxin, toxin is released from plant as protection

sequence of steps of herbivore protection

herbivore damage : system in release : jasmonic acid release : goes up phloem : defensive chemical

what are the types of photoperiodism

long day - short nights, flowers in early spring

short day - long nights, flowers in late summer, fall or winter

day neutral - flower as long as minimum day length is met

types of plant insect interactions

• co-evolution (flower and pollinator)

• herbivores/plant chemicals

• carnivorous plants

animal characteristics (some exceptions)

multicellular organisms, lack cell walls, heterotrophs (use other organisms for food), nervous tissue, movement, sexual reproduction, extracellular matrix (proteins bind animal cells together to give extra support and strength), characteristic cell junctions (specialized protein strucutres that connect adjacent cells, animals can have anchoring, tight, and gap junctions), special clusters of hox genes (function in patterning body axis), similar RNA

Choanoflaggellate ancestor

thought that most recent common ancestor was similar to choanoflagellates and similar to cells in sponges in the opisthokonta supergroup

animals are classified based on…

presence or absence of different tissue types, body symmetry, features of embryonic development

what are tissues

an association of many cells of the same type

metazoa

all animals

parazoa

sponges (and animals)

eumetazoa

true tissues

types of symmetry and define

radial - can make equal halves if cut in many different ways (jellyfish)

bilateral - can only make 2 equal halves if cut in one way (humans)

what is a diploblast and a triploblast

diploblast - 2 tissue layers when embryo

triploblast - 3 tissue layers when embryo

stages of embryonic development

• cleavage leads to the formation of a hallow ball of cells called the blastula

• gastrulation involves invagination of the blastula which creates the gastrula

• in the gastrula layers of cells become the endoderm, the outside cells of the blastula form the ectoderm and a middle layer called the mesoderm is formed

protosomes

when the blastopore becomes a mouth

deuterostomes

when the blastopore becomes the anus

what are all the groups of animals

kingdom animalia, metazoa, parazoa, eumetazoa, radiata, bilateria, protosomia, deuterozoa, lophotrochozoa, ecdysozoa

what group does a protosome fall under

lophotrochozoa

what is a coelom

a body cavity lined on all sides by mesoderm derived tissue

segmentation

division of structures (worm body)

tissue types and where they come from

muscle tissue (muscle cell)

nervous tissue (neurons)

epithelial tissue (epithelial cell)

connective tissue (connective cell)

steps to make an organism

differentiated cell →tissue →organ →organ system →organism

types of muscular tissue

skeletal, smooth, cardiac

functions of the different muscular tissue

skeletal - attatched to bone in vertabrates and provide force needed for locomotion, under voluntary control, striated/striped

smooth - often surround hollow tubes, control tubes diameter, involuntary muscle contraction

cardiac - only found in heart where muscle cells are interconnected and give force for heartbeat, involuntary muscle contractions

main functions of epithelial tissue + 1 example

protection, secretion, absorption + urinary system or lungs