EXAM 4 OVERVIEW Flashcards
Autotrophs
-self-feeding
-use carbon from simple substances to make organic compounds
-usually photosynthetic but can be chemotrophs
-Algae, plants, some prokaryotes
Heterotrophs
-other-feeding
-use carbon from other organic sources to make organic compounds
-gets energy from organic compounds
-animals, fungi, some prokaryotes, and protists
What part of the plant does photosynthesis
chloroplasts
shoot system of the plant
made up of stem, leaves, and reproductive organs
root system of the plant
typically everything underground, made up of roots
cuticle of the leaf
waxy protective layer
prevents water loss
epidermis of the leaf
cells that make the cuticle
protect the plant, similar to skin
stoma or stomata of the leaf
hold to allow air in and out
contains guard cells
mesophyll of the leaf
middle of the leaf
purpose is to do photosynthesis
palisade mesophyll of the leaf
long tightly packed cells
spongy mesophyll of the leaf
larger region less densely packed and does less photosynthesis
vascular tissue of the leaf
xylem and phloem running through
stem and root
usually non-photosynthetic
specialize in transport
What is needed for photosynthesis
sunlight, water, air (CO2)
Plants lose several 100 water molecules for each CO2 molecule that is fixed by photosynthesis because
the concentration gradient is many times larger for water than CO2
How does the leaf regulate water loss
Guard cells within the stomata regulate water loss. Plants use these to open/close the stomata
-use pumps going into cell
-use channels
-swell and deflate like water wings (turgid and limp)
What happens when the stomata is open
the stomata opens to do photosynthesis
What happens when the stomata is closed
The stomata closes to conserve water
Where does the dry weight of the plant come from
air
what happens in photosynthesis
air + water + energy yields sugar + oxygen
what are the two parts of photosynthesis
light reactions and the calvin cycle
what is the input of light reactions
sunlight, NADP+, ADP, H2O
what is the output of light reactions
ATP, NADPH, O2
light reactions consists of two interconnected systems; what do they do
one makes ATP and the other makes NADPH which are used to make carbs/sugars in calvin cycle
where do light reactions occur
in the chloroplast thylakoid membrane
where does the calvin cycle take place
in the stroma of the chloroplast
what happens overall in the calvin cycle
3 step process: fixation, reduction, regeneration
takes in CO2 and makes sugars
what occurs in the fixation step of the calvin cycle
add CO2 to carbon molecule and fixes carbon with RuBisCO, results in 2 3 carbon molecules, then CO2 goes to organic molecule 3PGA
what occurs in the reduction stage of the calvin cycle
3PGA is reduced to G3P
-uses ATP and NADPH
-remove 1 G3P: G3P is main output of calvin cycle
Regeneration
remaining 5 G3P is used to regenerate RuBP
this needs more ATP and allows the cycle to start over
sugar synthesis
G3P from Calvin Cycle (3 carbon building block for sugars)
requires NADPH, ATP
occurs in the cytoplasm
sucrose and other molecules made from these
what are the thylakoids in the chloroplast
flattened sacs
what are the granum in the chloroplast
stack of thylakoid
what is the stroma within the chloroplast
liquid matrix
Chlorophyll reflects….. and absorbs….
chlorophyll reflects green light and absorbs red and blue wavelengths
antenna complex
where the chloroplasts are grouped!
- electron excited by light energy
- energy transferred from chlorophyll to chlorophyll ending up at reaction center
-reaction center donates an electron to start an ETC
- overall, it absorbs light and transfers energy to electrons
reaction center
specialized chlorophyll that loses its electrons
photolysis of water (light reactions)
splitting water
-reaction center chlorophyll left without an electron
-steals an electron from water (oxygen evolving complex)
- water left without an electron (oxidized, water split into H+ ions plus O-, O- combines with another O- to make O2)
- O2 given off as waste gas and build up of hydrogens on the inside of the thylakoid membrane
moves electrons on to PS2
photosystem 2 (light reactions)
MAKES ATP & makes the H+ gradient
-ETC similar to ETC
- Makes H+ from H2O
- H+ is pumped from stroma to thylakoid lumen
- ATP synthase used H+ gradient to make ATP
Photosystem 1 (light reactions)
MAKES NADPH
what does a z-scheme show
drawing of the energy of the electrons
x-axis: proteins
y-axis: energy of electron
actually looks like an N
C3 photosynthesis
NORMAL PHOTOSYNTHESIS
Grabs CO2 from the spongy mesophyll for the Calvin cycle
Photorespiration
BAD ROUTE
RuBisCO takes O2 instead of CO2 so RuBP has to be regenerated
Happens more when stomata are closed (more O2)
Requires ATP to try again meaning energy intensive so its bad for the plants
C4 fixation
Way to get around photorespiration
Separates the fixation from rest of photosystem by SPACE AND ANATOMY; HOT CONDITIONS
- Bundle sheath cells surrounding the vascular tissue
- CO2 captured by PEP carboxylase to form 4 C molecules
CAM photosynthesis
Way to get around photorespiration
Separates fixation by TIME
BEST FOR PREVENTING EXCESS WATER LOSS; DRY CONDITIONS
-Night: stomata open, loses water, gains CO2, stores CO2 as a C4 acid in vacuoles
- Day: stomata closed, release CO2 to calvin cycle
Zombie Plants
Cut off roots and put into poison
- Plant dies but anatomy stays intact
- When roots are put into the water, they continue to draw up water for days
anatomy of the stem
-epidermis: cover and protect
-Ground tissue: support
-Vascular Tissue:
*diff arrangements of vascular tissue in diff lineages but always together
-Holds xylem and phloem
xylem
transport water and minerals
dead at maturity
energy comes from the sun
the source of energy that drives bulk flow comes from leaves
pressure= drinking straw
hollow inside
tracheids, vessel elements
phloem
transport sugar, proteins, hormones
pressure is like a garden hose
sieve tube elements
companion cells
Cohesion and tension
Water is polar
Cohesion Tension Theory
- Water evaporates from inside the mesophyll and creates pull from surface tension
- Cohesion pulls water up xylem in stem
- Negative water potential (osmotic pressure and pulling of water) draws water in from roots
Where is the pressure the lowest
in the atmosphere
Where is the pressure highest
roots
what is the driving force for moving water
transpiration of water aka evaporation from the leaves
what connects the water molecules to each other
hydrogen bonding aka cohesion
Reduced transport of water in plants
- Fewer stomata open in leaf
- Cool, humid weather
- High salt in soil creates low osmotic pressure in soil
Increase transport of water in plants
- More stomata open in leaf
- Hot, dry weather
cavitation
Too much negative pressure
-air comes out of solution
-also happens in freezing weather
Solutions:
-small diameter pipes
-small pores at the end of tracheids
Lignin
provides support for the cell walls in xylem and gives plants woody structures
sources
- where sucrose is put into transport
- made by photosynthesis (leaves)
- taken out of storage (starch to sucrose)
sinks
- where sucrose is taken out of transport
- used by mitochondria to make ATP
- put into storage (starch or storage vacuoles)
- converted into plant structure
examples of sources
leaves doing photosynthesis and storage roots during the early spring when they release food for growing leaves
examples of sinks
growing roots and flowers (they use more energy than they produce)
translocation
-Movement of sucrose from one location to another through phloem
-From source to sink
*Phloem loading
*Phloem unloading
-Explanation: pressure-flow hypothesis
phloem loading
- leaf cells produce lots of sucrose
*excess flows into phloem
*diffusion through plasmodesmata - sucrose can also be actively transported into phloem by proton pumps and H+/sucrose symporters
Phloem unloading
-facilitated diffusion to growing cells (convert sucrose to structure of energy)
-active transport to storage (move against concentration gradient)
functions of roots
absorb nutrients and water, anchor plant in soil, storage of macromolecules
rhizosphere
bacteria and fungi within soil around the root
- Plants secrete signals to promote growth of microorganisms around root
mycorrhizae
partially inside the root
FUNGI
GREATLY INCREASES SA
MOST PLANTS DO THIS
-plants and fungi team up: the plants do photosynthesis and provide sugars to fungi; the fungi absorb nutrients from soil and give some soil
-symbiosis: plants provide sugars to mycorrhizae
-loss of mycorrhizae reduces nutrient uptake by plants
- hyphae spread out in plant and absorb nutrients
exterior anatomy of the roots
Absorption of nutrients
*Root Hairs:
-cover surface of roots
-small projections of cells
-greatly increase surface area
*Epidermis
-protective skin
-no cuticle
-form root hairs
interior anatomy of the roots
Vascular Tissue (majority of the space)
-Xylem (water and minerals)
-Phloem (tissue for hormones, sugars, etc.)
Endodermis (wall around X&P)
-inner protection around vascular tissue
-keeps bad stuff out
-creates casparian strip: an impermeable barrier between cells
Pericycle: stem cells that can produce lateral roots
-just inside the endodermis
macronutrients
-used in high concentrations in plants
*lower concentrations in soil
-nitrogen, phosphorus, potassium
micronutrients
-used in lower concentrations in plants
*boron, chlorine, iron, copper, zinc
limiting factor
whats limiting heavy growth
rhizobia
bacteria that live in the roots
FIX NITROGEN
forms nodules
few plants do this
legumes
symbiosis
nutrient import
active process rather than absorption
symplastic route to the xylem
cuts through the cell
apoplastic route to the xylem
cuts through the cell walls and cant get through the endodermis without entering the cell (this prevents toxins from entering)
apoplastic route to the xylem
cuts through the cell walls and cant get through the endodermis without entering the cell (this prevents toxins from entering)
pollen
sperm producing gametophyte
*multicellular haploid structure that produces sperm
*can travel in dry air
*doesnt need flagella to swim in water
-pollen does not make sperm it just contains them
ovule
egg producing gametophyte
*multicellular haploid structure that makes eggs then becomes nutrient source for embryo
*larger than pollen and fixes to plant inside modified leaves (cone or flower)
spores
seedless plants with single-cell reproduction
microspore
pollen/male part
megaspore
ovule/female part
seeds
post-fertilization embryo
embryo packed in casing with food
common features of seed plants
*sporophyte dominant
*gametophyte is tiny and dependent
*seeds
*dry fertilization
gymnosperms
seed plant
cones are main reproductive structures
naked seeds
angiosperms
seed plant
flowers
seeds in fruit
*pollen producing structures (anther)
*ovaries enclosing the ovule
*ovaries mature into fruit
botanical fruit
culinary fruit
*sweet, juicy part of plant
culinary vegetable
*savory parts of plant
botanical fruit
*swollen ovary surrounding seeds
Which part of photosynthesis directly used ATP
rearranging molecules to form RuBP
the transfer of sunlight energy to electrons is accomplished by
chlorophyll
sucrose loading
generate the pushing force that creates the flow through sieve elements in the phloem
the tension in cohesion-tension theory refers to
the pulling force creates at the surface of a film of water
water exits the leaf through
transpiration
transpiration pulls water up through the xylem by
cohesion
sugar leaves the phloem by
diffusion
how do proton pumps impact potassium uptake
they decrease the positive charge within the cell to attract potassium ions
what do ferns require for fertilization
water
sweet fruits with many seeds help by
spreading seeds over a long distance
all seed plants also have
xylem and phloem
what anatomy do angiosperms have that gymnosperms do not
ovaries
gametes (n) go through fertilization and produce
a zygote (2n)
zygote (2n) goes through mitosis and produces
a sporophyte (2n, multicellular, diploid)
a sporophyte goes through meiosis and produces
spores (n)
spores go through mitosis and produce
gametophyte (n, multicellular, haploid)
gametophytes (n, multicellular, haploid) go through mitosis and produce
gametes (n)
