Sem 2, Unit 5: Plants + Photosynthesis

photosynthesis

how plants create carbohydrates for cellular respiration

1) endergonic

2) requires sunlight

3) occurs in the chloroplast

photosynthesis equation

6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

1) oxygen = a waste product because inhibits the calvin cycle

2) is the reverse of cellular respiration

plant

a multicellular organism that does photosynthesis

1) most use seeds to reproduce

plant characteristics (5)

1) are photosynthetic autotrophs

2) are non mobile

3) cell walls are made of cellulose

4) respond to their environment + grow through the use of hormones

5) need water and nutrients to survive

green algae

are the ancestors of land plants

1) are aquatic photosynthesizers

2) aren’t really plants because 1) live in water and 2) are mostly unicellular (can be multicellular though)

Plant Classification Categories

1) vascular system/tissue

2) seeds

3) flowers (enclosed seeds)

vascular tissue

for transportation

plant classification (vascular system)

plant = random plant

if( plant != vascular system)

{//bryophytes}

if (plant = vascular system)

{//tracheophytes}

bryophytes

plants without a vascular system

1) are the most primitive plants

2) live in moist/shady areas (don’t have transportation system so must get water through brute osmosis)

3) are small (b/c need to directly diffuse so can’t grow too big)

4) don’t have true roots/stems/leaves (look like them but tech. aren’t b/c no vasc. tissue)

5) are moss

bryophyte reproduction

reproduce with spores

1) spores = waterproof cells that grow into a new organism (not really a seed)

2) requires water b/c sperm swim to the egg

3) reproduction method is very similar

tracheophytes

plants with vascular tissue

1) contain 2 types of specialized vascular tissue for internal transport: xylem and phloem

2) vascular system allows them to grow more than bryophytes

3) includes true specialized organs (roots, stems, and leaves)

xylem

transports water from roots

phloem

transports nutrients from photosynthesis to the rest of the plant

leaves

let CO₂ and O₂ in/out for photosynthesis

1) covered in chloroplasts (where it occurs)

2) also let light reach chlroplasts

parts of a leaf

1) epidermis

2) palisade layer

3) spongy layer

4) veins

5) guard cells

epidermis

thin and clear first layer of a leaf that allows light in

1) has a wax coating to protect the leaf (cuticle)

palisade layer

densely padded layer of cells full of chloroplasts

1) maximizes the absorption of sunlight

spongy layer

cells with tons of air pockets

1) air pockets allow gases to diffuse through the leaf

DIAGRAM

CHECK

veins

contain specialized cells for support, water conduction, and food conduction

1) spec. tissue includes the xylem and phloem

guard cells

allow cells to regulate the intake of CO₂ and the release of O₂

1) close and open the stomata (the actual openings)

plant classification (seeds)

tracheophyte = a tracheophyte

if(tracheophyte != seeds)

{//fern}

if tracheophyte = seeds)

{//tracheophytes with seeds (not really a name)}

ferns

tracheophytes without seeds

1) have a vascular system (tracheophytes)

2) grow in most/shady places (b/c reproduce with spores still)

3) fronds = their underground stems, roots, and leaves

4) reproduce using spores

tracheophytes with seeds

have reproductive strategies that don’t need water like others with spores

1) use seeds

2) use pollen to spread sperm

3) use seed-bearing structures (cones + flowers)

seeds

how angiosperms and gymnosperms reproduce; contain…

1) fully developed embryo

2) food supply for the embryo

3) water-proof seed (keeps water from leaving/seed from drying out)

seeded tracheophytes classification

open or closed seeds

1) tracheophytes with exposed seeds = gymnosperms

2) tracheophytes with closed seeds (flowers/fruit) = angiosperms

gymnosperms

tracheophytes with open/exposed seeds

1) have three types: cycad, ginkgo, and conifer

2) use cones to reproduce

conifers

most common type of gymnosperms

1) have needles/scales for leaves

2) males produce pollen; females produce eggs + seeds

3) use cones to reproduce

conifer needles + scales

provide reduced surface area + have a waxy coat to help avoid water loss and prevent freezing

1) are perfect for plants in colder areas

pollen

collection of pollen grains

1) pollen grains = male gametophytes of a plant

1) sticks to the sticky part of stigma and grows a tube

conifer reproduction

1) male cones produce pollen (male gametophytes)

2) pollen makes its way to female cones that produce eggs

3) pollen fertilizes egg

4) egg becomes an embryo/seed

5) female scales of cone mature, dry out, and then open

6) seeds are scattered by the wind (inefficiently)

pollen transport (conifers)

pollen is transported by the wind, but the process is inefficient so produce tons of pollen (some might self pollinate, so it’s not the best process)

angiosperms

tracheophytes with enclosed seeds

1) use flowers for reproduction

2) produce fruit as a result of reproduction

fruit

the pollinated ovary in angiosperms that contains mature seeds

flowers

contain ovaries in which eggs/seeds are made in angiosperm reproduction

angiosperm reproduction (flowering)

allows for a direct + efficient pollen transfer

1) pollen is carried by a pollinator to the stigma of a flower

2) pollen sends sperm down the pollen tube + fertilizes an ovule

3) male part of flower also spermates the egg

3) seed coat grows around the seed embryo

4) multiple seeds grow within the mature ovary of the fruit

5) embryo grows into a plant after germination

plant cycle

{gametophyte plant} → mitosis (makes haploid gametes) → {fertilization} → mitosis → {sporophyte plant} → {meiosis} → {gametophyte plant}

red = haploid

blue = diploid

gametophyte stage

haploid stage of a plant’s life

1) produces gametes by mitosis (b/c start of haploid so don’t need meiosis again)

sporophyte stage

diploid stage of a plant’s life

1) produces haploid cells through meiosis

Sporophyte v Gametophyte Dominance

plants with dominant gametophyte forms:

-moss (small othr)

plants with dominant sporophyte forms:

- ferns (small othr)

- seeded tracheophytes (miscroscopic other)

pollinators

bats, flying insects, + birds that transfer pollen from flower to flower

1) = for angiosperms

complete perfect

an angiosperm with both male and female organs

types of fruit (to help with transporation)

1) winged fruit = glides to new location

2) floating fruit = floats to new location

3) fleshy fruit = brightly colored; survive in digestive system of animals

4) spiky fruit = have “velcro” that attaches to fur of animals

parts of angiosperms

1) sepals

2) petals

3) stamen

4) carpel

5) ovules

sepals

leaves of a flower

petals

modified leaves of a flower

1) usually brightly colored

stamen

the male parts of a flower

1) includes the anther, and the filament

anther

produces pollen

filament

the stick that supports the anther

carpel

the female parts of a flower

1) includes the stigma, style, and the ovary

stigma

where pollen sticks for fertilization

style

the tube that connects the stigma to the ovary

ovary

where sperm fertilizes the ovule

ovule

the egg

1) found within the ovary

seed coat

the covering around a seed

1) protects the seed from drying out (is waterproof)

micro pyle

the hole in the seed coat that allows the seed to absorb water

1) one place that’s not waterproof

hilium

attachment point on the seed for the ovary

parts of a seed

1) epicotyl

2) hypocotyl

3) radicle

epicotyl

part of the seed that grows into a leaf

hypocotyl

part of the seed that grows into a stem

radicle

part of the seed that grows into a root

cotyledon

part of the seed that does food storage

gymnosperm reproduction

use seeds for reproduction but don’t use fruits/flowers to enclose seeds

1) use cones

pigments

something that absorbs certain wavelengths (reflects the others)

1) are how light is absorbed for photosynthesis

higher wavelength

longer distance between points

lower wavelength

shorter distance between points

visible light range (#)

380-750nm

visible light range (explanation)

the light range humans can see

1) plants mostly use visible light range for absorption

chlorophyll (wavelengths)

absorbs all kinds of wave lengths but reflects green

absorbed vs reflected

1) absorbed wavelengths = used for photosynthesis as light energy

2) reflected wavelengths = not used for photosynthesis; are rejected/reflected and become the color that we see

absorption spectra

shows the absorption levels of a plant for different wavelengths

action spectrum

measures amount of released O₂ by a plant for different wavelengths

1) O₂ is a waste product of photosynthesis, so shows what light is being absorbed for photosynthesis

Engelmann’s Experiment

shows under which light/wavelengths aerobic bacteria gather the most with algae

1) algae produces O₂ as a waste product of photosynthesis; because bacteria are aerobic and require O₂ for cellular respiration, they gather wherever algae is photosynthesizing the most which is where they’re absorbing the most light

explanation for plants having multiple pigments

being able to absorb as many kinds of wavelengths as possible is good for photosynthesis; ready for anything

who can do photosynthesis (the three P’s)

1) some prokaryotes (bacteria)

2) some protists (euglena)

3) all plants (except ghost pipe plant bc bec. parasite)

plant cells (photosynthesis)

not all plant cells do photosynthesis

chloroplast structures

1) double membrane

2) ribosomes

3) thylakoids

4) lamellae

5) chromosomes

6) proteins

7) stroma

lamellae

connect different granums

granum

stack of thylakoid discs

stroma

the space within chloroplasts

double membrane (chlorplast)

probably because were eaten by eukaryotes (endosymbiotic theory)

parts of the thylakoid

1) thylakoid membrane

2) thylakoid space (space within a thylakoid)

chlorophyll

the main pigment for photosynthesis

1) made to be embedded into the membrane bc of its long carbonate tail (nonpolar)

2) embedded in the thylakoid membrane

3) has 2 types: chlorophyll A + B

4) has porphyrin ring

porphyrin ring

light-absorbing ring in chlorophyll a and b

light reactions

the first part of photosynthesis

1) occurs in the thylakoids

2) functions like the ETC of cellular respiration

3) includes photosystem II, photosystem I, and the ATP synthase

what goes into light reactions

light, H₂O, NADP+, ADP, and P

what comes out of light reactions

O₂, ATP, and NADPH

NADP+

electron carrier for photosynthesis

O₂ (light reactions)

= waste product of light reactions

1) needs to leave because inhibits the Calvin Cycle (rubisco)

Photosystems (II and I)

light-absorbing protein complexes within the thylakoid membrane

1) contain pigments like chlorophyll

Light Reactions Steps

1) photosystem II absorbs light which excites electrons and moves them to the ETC

2) ETC transports electrons to protein; protein uses electron energy to do active transport and move H+ ions across into the thylakoid space (making a gradient)

3) after electrons are transported, H₂O atom is split to get photosystem II its electrons back and repeat the function

4) electrons are transported to photosystem I where light is absorbed again; excites the electrons, and they move to 2nd ETC (no breaking of water molecule)

5) electrons are transported and picked up on a protein by NADP+ (electron carrier) along with an H+ atom; becomes NADPH

6) H+ that’s bene concentrated inside the thylakoid space moves down the ATP synthase, causing it to spin and produce ATP

7) NADPH and ATP go to the Calvin Cycle

photon

a package of light

1) used for photosystems II and I

Calvin Cycle

the second part of photosynthesis

1) occurs in the stroma (space of the chloroplast)

2) goal is to make the actual carbohydrate (G3P)

3) includes carbon fixation with rubisco

what goes into the Calvin Cycle

ATP, NADPH, and CO₂

1) ATP and NADPH = from light reactions

2) CO₂ = from the outside (pulled in through the stomata)

what comes out of the Calvin Cycle

G3P (sugar)

G3P

a building block for basically any carbohydrate (= ½ of glucose)

1) needs to be a building block for a lot of things b/c needs to be able to become everything plant needs

2) made by the Calvin Cycle

rubisco

key enzyme for the Calvin Cycle

1) takes CO₂ from the air and attaches it to sugars (= carbon fixation)

2) is the most abundant enzyme on the plant

3) inhibited by O₂ (why O₂ is a waste product of light reactions)

4) has 8 active sights for CO₂ but only 3 of them work b/c is extremely inefficient; plant has a ton of them to offset that

carbon fixation

the process of rubisco taking carbon dioxide from the air and attaching it to sugars (RuBP)

plant cellular respiration

plants do do cellular respiration but not as much as animals b/c aren’t very mobile

1) use a lot more CO₂ than they produce because are constantly doing photosynthesis and don’t move like animals

carbon cycle

1) plants take in CO₂ from atmosphere →

2) plants release O₂ from photosynthesis

3) animals take in O₂ (respiration)

4) decomposition takes in O₂

4) animals release Co₂ (respiration)

5) decomposition releases CO₂