Bio 201 Exam 2

plants are in nested clades

a set of organisms that share a common ancestor

plantae =

red algae and green plants

have plastid derived from primary endosymbiosis

green plants=

green algae and land plants

have modified plastid, a chloroplast

land plants

have adaptations for living on land - cuticle, pores or stomata

cuticle - waterproofing

must have gas exchange

pores in upper surface of thallus probably are the earliest structure for gas exchange

true stomata originate later, perhaps more than once

all exhibit alternation of generations

Embryophytes

land plants, multicellular embryo, protect embryo w sterile tissue and retained on mother plant

alternation of generations

sporic meiosis

alternate btwn haploid and diploid generations

meiosis = spores

mitosis = gametes

happens for land plants and some green algae

zygote

first cell of the sporophyte (2n) phases

sporophyte

diploid generation that produces spores

spore

haploid reproductive cell that can grow into an adult without the fusion of another cell - wall of sporopollenin

produced by meiosis

gametophyte

haploid generation that produces gametes

gamete

haploid reproductive cell

fuses together to form a zygote

produced by mitosis

syngamy

fusion of gametes to form a zygote

Bryophytes

non-vascular land plants

hornworts, mosses, liverworts

sporophytes is attached to, and is dependent on the gametophyte

embryo is retained by the gametophyte

vascular plants

have specialized conducting tissue

vascular tissue - xylem and phloem

support - increased height above ground

distribution of water and nutrients

Seed-free Vascular Plants

ferns and lycophytes

reproduce via spores - not seeds or pollen

have independent gametophytes and sporophytes

Seeded Plants

gymnosperms and angiosperms

have pollen and seeds

gametophytes are short lived and the female is retained on the sporophytes in the seed

gymnosperms

relatively small number of species but very diverse

ginkgo, cycads, gnetales, conifers

ginkgo

up to 80ft tall, deciduous w yellow foliage

temperate, resistant to pollution so common street tree

fan shaped leaves

cynads

first fossil evidence for 280mya

most common - cycas, zamia, macrozamia

restricted to tropical and warm temperate regions

gnetales

ephedra - 40 species

gnetum - 30 species

welwitschia - 1

deser plant with two leaves that continue to grow and split

conifers

sporophytes - tall,wide trees or shrubs, none herbaceous

monopodial growth, most evergreen, few deciduous

male gametophyte = pollen grain

female gametophyte = inside the ovule - becomes the seed

are the largest, the oldest, and the tallest living organisms

angiosperms - monocots -

cotyledons - 1

vascular tissue - scattered through stem

veins - parallel veins in leaves, bundles of vasc tissue

flowers -petals in multiples of 3

angiosperms - eudicots -

cotyledons - 2

vascular tissue -circular arrangement through stem

veins - branching veins in leaves

flowers -petals in multiples of 4 or 5

membranes - lipid bilayers

from when lipid molecules are aligned in paired sheets

hydrophilic heads - interact w water

hydrophobic tails - interact w one another

selective permeability

small, uncharged molecules cross membranes easily

ions, large molecules diffuse slow or not at all

assisted by membrane proteins

phospholipids

move within the membranes

in constant lateral motion, rarely flip to the other side of the bilayer

permeability’s relation to fluidity

higher temperatures increase fluidity

diffusion

spontaneous movement of molecules and ions

solutes move randomly in all direction

solute

dissolved substances

passive

no input of energyc

concentration gradient

difference in solute concentrations across the space

net movement away from regions of high concentration of the solute

occurs within fluids, gasses, and across membranes

equilibrium

molecules randomly distributed throughout the solutes

but the movement of the solute never stops

can occur during diffusion

Rate of Diffusion
F = kA ((∆c) / d)

F = rate of diffusion
k = diffusion constant (depends on solute, membrane, temperature)
A = surface area for diffusion
∆c = change in concentration
d = distance for diffusion (e.g., membrane thickness)d

diffusion w charged particles

charged particles rarely cross a phospholipid membrane on their own

must take into account charge and concentration

concentration and electrical gradient

electrochemical gradient

diffusion of charged particles depending on combo of concentration and electrical gradient

electrochemical equilibrium

combo of concentration and electrical gradient are balanced

consequence of size and shape - getting bigger

increased distance between surface and center

decreases surface area to volume ratio

increased diffusion distance - substances reach center at a lower rate

decreased surface area to volume ratio means

if surface area is smaller in relation to the volume then there is less surface through which diffusion can occur

decreasing SA:V

solution - become long and thin or flat to offset effects of increased size

vacuole

reduce internal volume

in plant cells they reduce the volume of the protoplast

osmosis

special diffusion case w water

semi-permeable membrane

only unbound water can cross the membrane

free water moves from regions of low solute concentration to high concentration - this changes volume and solute concentration

low concentration of solute = high conc of free water

high conc of solute = low conc of free water

semi-permeable membrane

allows water to cross the membrane but doesn’t let most or all solutes cross

polar

molecule is bent, carries a partial negative charge on one end and partial positive on the other

hypertonic

water flows out of the vesicle - shrinks

hypotonic

net flow of water into the vesicle, swell or burst

isotonic

no change

passive transport

when substances - ions or molecule - move across the plasma membrane in absence of an outside energy source

occurs along electrochemical gradient - doesn’t require energy expenditure

channel proteins are selective

carrier proteins

undergo a change in shape to carry a molecule

conformational change

selective

each protein only permits a particular type of ion or molecule to pass through

forming a pore to allow movement through the membrane

aquaporin

allow water to move across membrane but exclude other molecules and ions

gated channels

open in response to a signal

ex - voltage gated K+ channel

active transport

cells can move molecules in a directed manner or against the electrochemical gradient

requires energy investment

uses pumps

secondary active transport

gradient is used to move a molecule or ion of interest

these pumps move material against their concentration gradients and establish different electrochemical gradients

gradients power movement of another molecule against its gradient - atp not directly used to power, electrochemical gradients power

cotransport

pump

membrane protein that provides active transport of molecules across the membrane

proton pump H+ ATPase

uses atp to move protons H+

often important in change to pH and creating electrochemical gradient

sodium-potassium pump - Na+/K+ - ATPase/K+-ATPase)

uses atp

transport Na+ and K+ against their concentration gradient

cotransporters - symporter

transport solutes against their concentration gradient using energy released by the transport of another molecule moving in the same direction along its concentration gradient

cotransporter - antiporter

transport solutes against their concentration gradient using energy released by the transport of another molecule moving in the opposite direction along its concentration gradient

tree of life 3 domains or 2?

1. bacteria 2.archaea 3.eukaryotes

or

1. bacteria 2.archaea and eukaryotes

eukaryotes

1. cells tend to be larger than bact + arch with more organelles and more extensive cytoskeleton

2. have nuclear envelop - membrane barrier separating nucleus from cytoplasm in eukaryotic cells

3. multicellularity has evolved many times - rare in b + a

   1. reproduce asexually via mitosis or sexually via meiosis

protists

nott monophyletic but paraphyletic

all eukaryotes except land plants, fungi, and animals

eukaryotes lineage split bya and lots of divergence

no synapomorphies

protists just 10% of species but super abundant

paraphyletic

a group containing a common ancestor and some of the descendants

crop diseases

irish potato famine caused by protist Phytophthora infestans - water mold

plankton

diatoms and other small organisms that drift in the open ocean or lakes

form bottom of food chain - nutritional relationship among organisms

primary producers

species that produce chemical energy by photosynthesis

photosynthesis

conversion of light energy from the sun into chemical energy - carbohydrates - used by organisms

energy is stored in tissues as starch, sugar, and cellulose - wood, coal, gas, oil

stored energy can be released by burning or metabolism

source of oxygen in the atmosphere

photosynthesis equation

6CO2 + 6H2O = C6H12O6 + 6O2

light energy is used to reduce carbon, removes hydrogen from water and adds it to carbon

carbon

essential element of all life forms

carbon sinks

long - lived carbon repository from marine protists

sedimentary rocks

from protist shells made of calcium carbonatep

petroleum

accumulation of dead bacteria, archaea, and protists at the bottom of the ocean

respiration

takes sugars and metabolizes them for energy

carried out by all living organisms

mitochondria

all eukaryotes have them or genes normally found in mito

organelle that generates ATP using pyruvate as the electron donor and oxygen as the ultimate electron receptior

semi - autonomous

semi-autonomous

organelle replicates via fission, have own ribosomes and manufacture some of own proteins, have own genome - arranged as circular molecular as in bacteria, double membrane, similar in size to proteobacteria

ATP stands for

adenosine triphosphate

theory of endosymbiosis

mitochondria originated when a bacterial cell was taken up by a host cell

Lynn Marguis finally accepted in 1970

most profound evidence - orgin of the mitochondria is the close relationship between the mitochondrial genome and bacterial genomes - used lateral gene transfer

endo

inside

sym

together

bio

living

plastid

also hypothesized to have originated by endosymbiosis

protist - multicellularity

arose independently in many different lineages

allows specialization

not all cells can express the same genes so it allows for an organisms body to built in many ways

slime molds

cells can live independently part of the time but also make up a cohesive multicellular reproductive structure

protists structures provide

support and protection

foraminiferans - make up the white cliffs of dover

protists obtaining food

can be autotrophic or heterotrophic

ingestive feeding, phagocytosis, absorptive feeding, photosynthesis

autotrophic protists

can synthesize their own complex organic compounds from inorganic sources

heterotrophic

must digest organic compounds for nutrients - including parasites

ingestive feeding

eating live or dead organisms or organic debris

phagocytosis

engulf food

novel method for securing nutrients take in food much larger than single molecules

absorptive feeding

nutrients are taken up directly from the environment

usually cross the plasma membrane using transport proteins

can be parasitic or decomposers

protist - mobility

many move actively to find food

amoeboid motion, flagella, cilia

amoeboid motion

pseudopodia streams forward and rest of the cell follows

flagella

a long cellular projection that undulates - in eukaryotes to push a cell through and aqueous environment

dinoflagellates

have 2 flagella

create red tides - huge population growth = blooms

fish, bird, turtle, manatee, and dolphin death

neurotoxic shellfish poisoning - harm people who eat shellfish

also toxin in aerosois - breath it in

opisthokonta

have single flagellum

cilia

short, filamentous projections that move the cell or circulate fluids

life cycle

sequence of events that occur as an individual grows, matures, and reproduces

asexual

any mechanism of producing offspring that doesn’t involve the production of and fusion of gametes

based on mitosis - in eukaryotes

chromosomes in the daughter cell are identical to chromosomes in the parental cell

sexual

the production of offspring through the production and fusion of gametes

requires meiosis - reduced the number of chromosome sets

offspring have chromosome complements different than both parents

life cycles affects

relative timing of mitosis and meiosis affects the overall lifecycle

mitosis facilitates growth of a multicellular body

meiosis and syngamy change chromosome numbers

syngamy

union of gametes

fertilization is a type of syngamy - union of a flagellate sperm and a non-motile egg

haploid

1 set of chromosomes