midterm 2 bis2c, lectures 13, 14, 15

T or F

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the mitochondrion and chloroplast evolved only one time in the evolution of eukaryotes

T ( evolution is not related to secondary and tertiary endosymbiosis)

Algae

entirely aquatic plants, not monophyletic

advantages to living on land

more access to carbon dioxide, more sunlight

Challenges to life on land given the aquatic ancestry

* desiccation
* no support for body
* reproduction

Glaucophytes

* freshwater, unicellular algae that have a layer of *peptidoglycan* in their chloroplasts
* (evidence that chloroplasts arose via primary endosymbiosis because chloroplasts were once bacteria)
* Uses chlorophyll a (same as cyanobacteria)

Green Plants

* uses chlorophyll a and b
* increased photosynthetic capacity
* ability to store starch

The four adaptations to life on land

* sporophyte
* waxy cuticles
* protected embryos
* sporopollenin

( all related to the land plant life cycle)

mitosis

no change in the copies of chromosomes per cell (2n→ 2n, n→ n)

meiosis

reduction of chromosomes per cell

(2n→ n)

Diplontic life cycle

* diploid stage is dominant and multicellular (2n)
* no multicellular haploid stage (n)
* does not occur in plants

T or F

In eukaryotic life cycles, the embryo results from the meiotic division of the zygote

F, it is mitosis not meiosis

Do plants make gametes by meiosis or mitosis?

mitosis

What are zoospores

\-the product of 2n zygote undergoing meiosis resulting in four swimming spores

Haplontic life cycle (most but not all algae)

Has a dominant and multicellular haploid adult but no multicellular diploid stage

Alternation of Generations

has both adult, dominant haploid and diploid stage ( gametopyte and sporophyte)

bryophytes

early- diverging land plants

* non vascular
* lack lignified vascular tissue (xylem and phloem)
* no leaves or roots ( has rhizoids)
* diffusion
* low to the ground and small

T or F

Bryophytes are monophyletic

F

Poikilohydry

water content matches that of the environment

If bryophytes lack xylem and phloem, by what process does water enter cells?

diffusion

Bryophyte body plan

* dominant gametophyte generation (main body)
* smaller, nutritionally dependent sporophyte generation

Archegonia

structures that produce eggs

antheridia

structures that produce sperm (must swim to the archegonia)

sporopollenin

protein that coats the outside of spores to reduce water loss

Liverworts body plans

* thallose
* leafy
* they have the smallest sporophytes in land plants

sporangium

container of spores (moss has them)

hornworts

* has persistently green sporophyte with indeterminate growth

What is not evidence that supports the endosymbiotic origin of the chloroplast from cyanobacteria?

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* use of chlorophyll a by glaucophytes
* multiple membranes around the chloroplasts
* haploid chloroplast genome
* peptidoglycan in the chloroplasts of bryophytes
* circular chloroplast DNA

* peptidoglycan in the chloroplasts of bryophytes

Do bryophytes or glaucophytes have peptidoglycan in the chloroplasts?

glaucophytes, they are the only lineage that have peptidoglycan- very good evidence of the endosymbiosis of the chloroplast

In homosporous alternation of generations:

one sporophyte produces one size of spore

Hornworts in contrast to other bryophytes have:

persistently green sporophytes

Plasmodesmata

cell to cell junction in plants ( strong evidence that multicellularity evolved independently )

What is in a primary cell wall?

cellulose and hemicellulose (no lignin)

What is in the secondary cell wall?

Cellulose, hemicellulose, and lignin

Meristems

regions of undifferentiated cells, can develop into any different types of plant tissue

What are the two types of meristem

apical and lateral

What are the two types of apical meristem

SAM and RAM

Dermal tissue

form the epidermis and secrete waxy compounds that protect the plant from desiccation

Vascular Tissue

(xylem and phloem) transport water, minerals and sugar

Ground tissue

fills in the inner space of the plant and performs metabolic and storage functions.

purpose of lignin

Bryophytes do not have lignin, plants that need to grow tall have it.

What are the 3 types of ground tissues

parenchyma, collenchyma, sclerenchyma

Parenchyma

does most of the work

* photosynthesis happens
* sugar is stored
* alive

Collenchyma

Celery

* bendy
* alive
* support

Sclerenchyma

* dead, woody tissue (attached to lignin)
* toughest

What are the four organs?

Leaves, Stems, Roots, Flowers

Parts of the leaves

Blade, Midrib, petiole

stomata

where gas exchange occurs for photosynthesis

guard cells ( for stomata)

like lips, closes if it gets too dry

Difference between leaves and stems

Stems have meristem and leaves do not.

* They also have nodes

What are nodes and internodes?

* nodes: collections of meristematic tissue from which leaves or other organs grow
* internodes are the sections of stems between nodes

How to tell the difference between leaves and stems

the presence of nodes

What are the parts of roots

* root apical meristem
* root cap
* root hair

What do root hairs do?

they increase surface area for water and mineral absorption

What do root caps do?

protects the RAM, secretes lubricant for easier growth

Tracheids

* first type of xylem tissue that evolved
* all vascular plants have tracheids

What are the innovations of vascular plants

tracheids, roots, bigger sporophytes

Are bryophytes gametophyte or sporophyte dominant?

gametophyte

Are vascular plants gametophyte or sporophyte dominant?

sporophyte

Advantages of larger sporophytes

They have wider range to disperse spores as well as more production

What are the two types of vascular tissue

xylem (water) and phloem (sugar)

Two types of xylem

* trachieds (all vascular plants)


* vessel elements (some vascular plants)

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(dead)

Phloem parts

* sieve tube- flow of sugar (no organelles)

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* companion cells- regulates sieve tube

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(alive)