Bio Midterm 1

What are the 3 domains of life

bacteria, eukarya, archae

serial endosymbiosis

how eukaryotes evolved from prokaryotes

endosymbiosis

A process where one cell(endosymbiont) lives within another cell(the host)

How did mitochondria evolve

aerobic bacteria was swallowed by a more complex archaea

How did chloroplats evolve

photosythetic bacterium engulfed by ansetral prokaryote

Proof of serial endosymbiosis

1. circular genome chromosomes like bacteria

2. Replicate simialr to bacteria

3. organelles transcribe their own DNA

4. Inner membranes have enzymes and transport systems similar to bacteria

5. ribosomes similar to bacteria

Why study plants

oxygen, food, beverage, animal feed, drugs, fibers

Linnean hierarchy

narrow to broad; species, genius,family, order, class, phylum, kingdom

Genera naming

genus+aceae

Species

Group of individuals that when they interbreed:
➢ produce fertile progeny without artificial
intervention

Subspecies

Capable of interbreeding but not in nature human intervention neededp of individuals

Intergenetic hybrids

fertile progeny involving 2 genus, X is used to indicate genus cross

plant histoyr

non vascular plants (mosses), vascular plants(ferns/seedlings), Vascular plants(flowers

angiosperms consist of 3 thinsg

flower, fruit, double fertilization

Monocot

1 cotyledon, flower parts in 3s, paralle vines, primary root replaved by adventious root, scatterd vasculature, 1 pollen pore, corn

Dicot eudicot

2 cotyledon, 5-4 flower parts, network of viens, ring formation vasculature, primary root/tap root, 3+ pollen pore

Alternating generamition

alternating between sporophyte, and gametophyte

mitosis

one cell divides, and produces 2 identical daughter cells diplpoid cell (2 chromosomes)

meiosis

one cell divides and produces 4 cells with ½ number of chromosomes (haploid) spores

sporophyte produces

spores haploid

gametophyte

produces gametes haploid

Alternation generation

uses both mitosis and meiosis alternate between the sporophyte and gametophyte generation

Male and female gametophytes in gymnosperms(non flowering) what is the sporophyte

pollen cones, ovulate cones, main body of plant with stems

Male and female gametophytes in angioosperms(flowering) what is the sporophyte

ouvle, pollen, main body of plant with stems

What are seed plants dependant on

sporophyte tissue for nutrition

In mosses what generation is predominant

gametophyte

In ferns what generation is predominant

50/50

In gymnosperms and angiosperms which is more predominant

sporophyte

What is the main life cycle in angiosperms

Adult (sporophyte) phase is the main life
cycle phase

Angiosperms are heterosporous

they produced 2 spores, microspores (male→pollen grains), megaspores(female→ ovule)

Stamen male parts

anther and filament

carpels female parts

stigma, style, ovary

Angiosperm life cycle

1. In anthers microsporocyte divide me to produce 4(n) microspores

2. In ovule megasporocyte divide me produce 4(n) megaspores ¼ survives

3. microspores divide mit produce pollen grain

4. megaspores divide mit, 7(n) eggs, synergids, antipodals, polar nuclei

5. pollen grain lands on stigma and pollinates

6. Pollen grain germinates tube cell creates tube down style, generative cell follows 2 sperms in generative cell, 1 fertilizes egg (2n zygote) other fert polar nuclei(triploid 3n)

7. zygote turns into embryo, triploid turns into endosperms

8. seed germinates, sporophyte matures cycle repeats

A flower is a reproductive structure that

produces gametes (ovule, pollen, egg & sperm)
➢ protects and nourishes the
megaspore gamete (carpel)
➢ captures the male gametes
(pollen)
➢ nourishes the embryos
➢ develops seed(s) and fruit(s)

What is a seed

An embryo and a nutrient source
surrounded by a protective coat

What is a fruit

enlarged ovary that contains seeds

The flower is the ———— shoot
of an angiosperm

reproductive

A complete flower consists of 4 whorls

1. sepals mod leaf

2. petals mod leaf

3. stamens

4. carpels

Incomplete flower

lack 1+ whorl

Inflorescence

cluster of flowers, wild carrot

Perfect flowers

flowers that contain both male and female parts

Incomplete flowers:Monoecious

male and female flowers are separate but on the same plant (zuchinni)

Incomplete flowers: Dioecious plants

male and female flowers are found on separate plants (willows)

What do pollen grain walls contain

sporopollenin, very hard material make for good fossils

Pollination vectors and percentages

Animals 80% Abiotic 20%-wind 98%-water2%

how many plants are animal pollinated

250,000 and pollinated by 100,000 animals including invertebrates and vertebrates

Flower methods of attraction

1. flower colour

2. nectar

3. odour

4. deception/mimicry

5. timing of pollen

6. flower shape

   *may be more metabolically efficient than relying on wind→ creating lots of pollen)

Nectar and pollen rewards

pollen protein, nectar sugar 13 amino acids

Characteristics of flowers pollinated by birds

-range from scarlet to red to orange and generally lack nectar guides
➢ have very deep tubes usually without a landing platform, are pendant or horizontal, and
➢ have abundant nectar but emit no odor,

Bats as pollinated flower characteristics

-open at night, similar to moth-pollinated flowers
➢ are positioned below the foliage of the plant
o hanging pendant on a long pedicel or attached to the trunk or low limbs
➢ are drab white, green, or purple, bats are color-blind
➢ exude a strong musty odor at night, fermenting fluid, cabbage, or bats themselves
➢ large and tough, with lots of pollen and nectar

some have more than 1300 anthers and 7 to 15 ml nectar

Co-evolution

plants and the animals that pollinate them have co-
evolved
• in some cases, the flowers have shapes that are only accessible to certain pollinators buff-tailed sickle bills

Wind pollinated flowers tend to be

small, colorless, odorless, and lacking in nectar, lacking petals or have petals reduced to small scales, have flowers dangle in or wave

Where do grasses and sedges position their flowers

above leaves so they are exposed to the wind

Why are wind-pollinated pollen grains (frisbee shaped) smaller than animal-pollinated pollen grains

so they can be carried through the wind more easily 20-60 micrometers compared to 13-300

where are the flowers in corn

tassel staminate flowers, ear female flower, silk is stigma

Self-pollination/Selfing (10-13% of plants)

transfer of pollen from the anther to the stigma in the same flower and transfer of pollen from one flower to another on the same plant

Cross-Pollination or outcrossing

involves transfer of pollen from one genetically distinct plant to the stigma of another, increases the genetic diversity in the offspring

Selfing advantages

widespread propagation of the same, adapted, genotype
➢ no need for wind or pollinators
➢ little “metabolic cost”
o little wasted pollen
o no cost to produce nectar or other characters to attract pollinators

3 traits of angiosperms

1. Flowers

2. Fruits

3. Double fertilization

Disadvantages of self-fertilization

➢ restricted opportunity to create new genetic
combinations

-limited genetic diversity might lead to local extinction if pest & growing conditions change
• inbreeding depression
• loss of vigour
➢ may be caused by expression of deleterious
traits determined by recessive alleles
Homozygous individuals-AA or aa

Mechanisms that promote cross pollination

1. Monoecious and diecious plants

2. Heterostyly (heteromorphic self-incompatibility) the condition (e.g. in primroses) of having styles of different lengths relative to the stamens in the flowers. Thrum long stamens (male) pin long styles(female)

3. Genetic incompatibility

Genetic incompatibility

the ability of a plant to reject its own pollen and sometimes the pollen of closely related individuals based off of

→ Gametophytic self-incompatibility: In gametophytic self-incompatibility, the S-allele in the pollen genome governs the blocking of fertilization s1 cant fertilize s1s2 flower pollen tube will not germinate

→Sporophytic SI: fertilization is blocked by S-allele gene products in tissues of the parental sporophyte that adhere to the pollen grain wall, due to the parental tissue attached to the pollen wall.

A seed consists of and is

An embryo and nutrients surrounded by a protective coat, mature ovules that contain the
embryonic plants of the next generation

Oldest seed germination is

32,000 recovered from Siberian permafrost, silene stenophylla

Seeds and fruits are filled with stored foods intended to

→help the embryo germinate and grow
➢ or to attract an animal to eat the fruit and inadvertently carry seeds away

What vegetables are also considered fruits

string beans, eggplant, okra, tomato, squash, cucumber

Simple fruits

develop from a single or several fused carpels of one flower pea, fleshy or dry, can be dehiscent (open or discharge seeds) or indehiscent (they don’t open or discharge seeds) The thin skin derived from the outer layer of the ovary. The soft
fleshy skin is derived middle layer of the ovary and stony pit is derived from the inner tissue layer of the ovary.

Aggregate fruits (single flower multiple carpels(ovaries)

This process starts with a flower that contains several carpels with an equal number of ovaries. Each ovary contains a single ovule that develops into a seed following fertilization. As the ovaries develop and increase in size they attach. Each fruit in the aggregate is a drupe containing a stony pit.

Multiple fruits (develop from inflorescence)

ovary walls thicken they fuse together and become incorporated into 1 fruit

Accessory fruit (develops from tissue other than ovary)

strawberry fruit is enlarged receptacle tissue
➢ the dry “seeds” embedded in the
red tissue are achenes (or true
fruits) similarly, an apple is made up of
mostly enlarged hypanthium tissue
(which connects sepal, petals and
stamens in the flower)
➢ the core of the apple is the fruit

Fruits that develop without fertilization are ______ and called_____

seedless, parthenocarpic grapes, eggplant, watermelon

Plants that do not require pollination or other stimulation to produce parthenocarpic fruit exhibit

vegetative parthenocarpy

some plants, pollination (with dead pollen) or another stimulation is required for parthenocarpy called

Stimulative parthenocarpy

Seed wind dispersal characteristics

winged, plumed, ballistic dispersal

Animal seed dispersal techniques

attachment strategies, food reward

What is scarifying

breaking seed coat to speed up germination

The only stored food for seedling is

the endosperm and cotyledons

it costs the plant more to make seeds and fruits than it does to make

vegetative organs

Impermeable seed coats are broken by

passage through the animal tract, mechanical nicking freezing, thawing

Steps in germination eudicots

1. Water intake through micropyle

2. Enzymes break down food stored in cotyledon, which are transported to the radical for growth, radical pushes out

3. a hook forms in the hypocotyl, and growth pushes the hook above ground

4. the hypocotyl and radicle start growing and emerge out of the seed

5. the brown seed coat starts to peel off from top to bottom

6. hypocotyl from the seed appears green and is bent downward extends to the radicle that starts to develop into a root

7. The cotyledons are pushed half above the soil the hypocotyl straightens, pulling the cotyledons completely out
   • foliage leaves emerge from the cotyledons and light straightens the shoot tip

Germination is the apperance of the

radical and shoot from the seed

Emergence is the apperance of the

seedling shoot above the soild surface

epigeal

cotyledons emerge from the ground

hypogeal

cotyledons remain in soil

Monocot seed germination

1. coleoptile pushes up through the soil creating a tunnel for the shoot tip to grow through

2. coleoptile and radicle start growing
   and emerge out of the seed

3. The coleoptile faces upward and
   radicle faces downward

4. the radicle develops into a root
   below the soil

5. the shoot grows straight up through the tube of the coleoptile to establish the foliage leaves of the
   seedling

Vascular plants have 3 organs

leaves, stems, roots

Root and shoot dependency

shoots rely on water and minerals absorbed by the root system and roots rely on sugar produced by photosynthesis in the shoot system

Plant cell features

membrane-bound nucleus and organelles like edoplasmic reticulum, golgi, mitochondria, but are unique and have cell wall, chloroplats, and central vacuole

The microfibrils are embedded within a noncellulose matrix, which can account for 60 -80% of primary cell walls, composed of

hemicelluloses (branched polysacchride) pectins(hetergenous mixture of sugars rich is galacturonic acid), extensins(glycoproteins)

microfibrils

celluslose in orthogonal layer

What is chlorophyl

chlorophyl is the green pigment in chloroplast which captures light

Where do light harvesting reactions take place

thylakoid membrane

Where does sugar synthesis take place

in stroma

Plant tissue falls into 2 categories

Meristematic and permanent tissue.

Meristematic tissue cells are either undifferentiated or incompletely differentiated; they continue to divide and contribute to the growth of the plant.

Permanent tissue consists of plant cells that are no longer actively dividing.

What are meristems

plant regions where there is cell division and continuous growth

What are the 3 meristematic tissues

apical, intercalary, lateral meristems

Apical meristems found and do what

located at the tips of stems and roots, which enable a plant to extend in length

Lateral meristem found and do what

found in the vascular cambium of stems facilitate growth in thickness or girth in a maturing plant

Intercalary meristems found and do what (monocots only)

occur at the bases of leaf blades and at nodes enable monocot leaf blades to increase in length from the leaf base i,e lawn grass

Primary meristems 3 permanet tissue types

dermal(covers protects plant), ground (site for
photosynthesis, provides a supporting matrix for
the vascular tissue, store water
and sugars), vascular(transports water, minerals, suagrs)