Plant Science 2125 Exam 1 - Hagely

cambium

meristematic tissue that gives rise to secondary growth

stroma

fluid portion of the chloroplast; surrounding the thylakoids

pectin

matrix polysaccaride
acts as a hydrophobic filter (matrix to control what does in and out)
has +Ca ion, which pulls - charges in backbone

sieve-tube elements

connected to companion cells through sieve areas
in the phloem
(all nucleus activities in companion cells)

angiosperms

flowering plants

meristems

localized regions of ONGOING cell division that enable growth during post-embryonic development

primary growth

the phase of plant development that gives rise to new organs and to basic plant form (gives rise to primary plant body)

primary plant body

the part of the plant derived from the shoot and apical meristems and primary meristems

secondary growth

the increase in width or diameter of shoots and roots that happens to a plant as it grows

cork cambium

the phellogen; cambial layer that produces the protective periderm on the outside of woody plants

vascular cambium

cambial layer that produces wood; arises in the vascular system between the xylem and the phloem of the primary plant body

secondary xylem

dilutes; on the inside

secondary phloem

energy; on the outside

radial rays

splits in wood

fluid-mosaic model

the common molecular lipid-protein structure for all biological membranes

phospholipid head

phosphate, hydrophilic

phospholipid tail

lipid, hydrophobic

saturated lipids

straight structure, all single bonds (no double bonds)

unsaturated lipids

bent structure, has a double bond that kinks the shape

True or False: Lipids are also in leaves

True

what are the parts of the endomembrane system

plasma membrane
endoplasmic reticulum
nuclear envelope
vacuole
endosomes

what are semiautonomous organelles?

cells that have their own genome (DNA)
examples:
mitochondria
plastids (chloroplasts)

endoplasmic reticulum

rough and smooth, outer layer cortical ER

vacuole

plants have one large, central one
plays a structural role -> turgor pressure

endosymbiotic theory

a theory that states that certain kinds of prokaryotes began living inside of larger cells and evolved into the organelles of modern-day eukaryotes

what are examples of plastids

chromoplasts, leucoplasts, amyloplasts, chloroplast

mitochondria

cell energy -> ATP synthesis takes place

mitochondrial matrix

the compartment of the mitochondrion enclosed by the inner membrane, ATP synthesis happens here

mitochondrial cristae

folds in the inner mitochondrial membrane that have many proteins embedded in it (helps increase surface area)

what is the most abundant macromolecule on earth?

RuBisCo

chloroplasts

a plastid, place of photosynthesis

thylakoid

a membrane system found within chloroplasts that contains the components for photosynthesis

grana (granum)

stacks of thylakoids

thylakoid lumen

fluid filled space inside the thylakoid, where ATP synthesis takes place in the chloroplast

plant cytoskeleton

composed of microtubules and microfilaments

what does the cytoskeleton do?

organizes movement

microtubules

hollow, made of tubulin

microfilaments

not hollow, made of actin

how do cell walls have good mechanic strength?

lignin!

what are the 7 things cell walls do?

connect adjacent cells
act as an exoskeleton
determine plant shape
act as different barriers
provide anchor point for sensory proteins
act as a barrier to pathogens, parasites, and herbivores
provide strength for the xylem

middle lamella

cements the walls of neighboring cells together

primary cell walls

characteristic of young cells
thin and flexible

secondary cell walls

thick and strong
fortified after the cell has stopped expanding (lignin and cellulose)

cellulose

in the cell wall
made of many glucose units (polysaccharides)

rank the largest until to the smallest unit of the cell wall

lamellae (largest)
fibers
macrofibrils
microfibrils
molecules (polysaccharide)
glucose units (monosaccaride)

cellulose microfibril deposition determines what?

determines the directions of cell expansion

hemicellulose

matrix polysaccharide
made in the golgi body
primary or xyloglucan

how does hemicellulose work?

made in the golgi body
vesicles move off the golgi body
moves to the plasma membrane
lipids crash and release contents
taken to where it's needed in the cell

what is the most abundant in primary cell walls?

pectin

plasmodesmata

"the carpool lane"
channels through cell walls that connect the cytoplasms of adjacent cells

is the transport in the plasmodesmata size dependent?

yes

symplastic transport

movement is through plasmodesmata connecting cytoplasm of cells

apoplastic transport

movement along cell walls and intercellular spaces (not plasma membrane)

dermal tissue

outer protective layer; called the epidermis in the primary plant body

ground tissue

fills ups the bulk of the plant (the guts)
three types

parenchyma

living cells with thin primary walls
has the capacity to continue dividing
crucial for regeneration and wound healing
can become embryonic cells (totipotency)

what make up most stems, leaves, and roots?

parenchyma

collenchyma

thickened primary cell walls
can continue to elongate
have distinctive, unevenly thickened and non-lignified cell walls
typical supporting tissue of new and growing organs

what is often found under the epidermis and petioles?

collenchyma

schlerenchyma

two types: fibers and sclerids
have thick, lignified secondary walls
crucial in strengthening plant tissues that have stopped elongating

fibers (schlerenchyma)

long, slender, and occurring in bundle
high tensile strength

sclerids (schlerenchyma)

relatively short
variable in shape
often branched

vascular tissue

plumbing system of the plant
two types: xylem and phloem

xylem

primarily moves water (moves minerals too)
non-living at maturity
contain tracheids and vessel elements
develop by carefully orchestrated differentiation followed by apoptosis

traecheary elements

xylem cells that move water and minerals from the root

phloem

moves nutrients (photosynthate) from leaves to root and up to flowers and seeds
are living at maturity (never dies)
non-lignified cell walls
sieve-tube elements stack to form sieve-tuble elements in angiosperms and sieve cells in gymnosperms

nuclear envelope

a double membrane that surrounds the nucleus in the cell
dotted with nuclear pores

nuclear pores

selective channels made up of nucleoporin proteins

chromosomes

DNA and associated proteins

describe where DNA is

DNA is wrapped around histones, which forms nucleosomes

what is the fundamental difference between plants and animals

plants:
plant haploid gametophytes, produce gametes by MITOSIS

animals:
animal haploid gametes, produce gametes by MEIOSIS

similarity of plants and animals (regarding haploids)

life cycle:
when haploid gametophytes fuse in fertilization, the 2N zygote is created and the life cycles of the two are similar

alternation of generations

plants alternate between two types of generations

what are the two types of generations plants go though

diploid sporophyte cells that produce spores
haploid gametophyte cells that produce gametes

who was Gregor Mendel

"father or genetics"
worked on blending inheritance

who originally thought of blending inheritance?

Aristotle

blending inheritance

offspring showed characteristics similar to both parents

what 7 character differences did Mendel observe

flower position
flower color
stem length
pea shape
pea color
pod shape
pod color

what is the flaw in blending inheritance

not always the case
pea plants!!!!

steps to pollination (basic)

1. pollen develops in Anthers
2. eggs needed in the ovule (unfertilized)
3. pollination happens when pollen from the anthers goes to the stigma
4. pollen moves down to the ovule (via pollen tubes)
5. nuclei of sperm cells and eggs unite

how do you cross-pollinate pea plants?

you have to stop the self-pollination process (pea plants typically self-pollinate)
you dust the pollen from one onto the stigma of another

what is a monohybrid cross

a cross between individuals heterozygous for a single character (AA x aa)

Mendel's Principle of Segregation

individuals carry pairs of genes for each trait and these pairs separate during meiosis

Mendel's Principle of Independent Assortment

the alleles of a gene segregate independently of the alleles of other genes

what is linkage

the case where 2 genes are close together on the same chromosome, such that they do not assort independently in meiosis
presents problems in plant breeding

who discovered mutations

Hugo de Vries

what are types of mutations on the gene level

insertion
deletion
inversion (switches pairs AB -> BA)
substitutions

what are types of mutations on the chromosome level

entire segments can be altered
entire chromosomes can be added or lost
translocations: an arm of a chromosome is switched with another

when would mutations be a good thing

it can provide the raw materials for evolutionary change
occurs spontaneously (1 mutant per 200,000 cell divisions)

transposons

"jumping genes"
repetitive elements that duplicate and move independently

T or F: a small part of the eukaryotic genome is composed of transposons

False: a LARGE part of the eukaryotic genome is composed of transposons

Arabidopsis thaliana

thale-cress
the OG plant model organism

why is Arabidopsis thaliana a model organism?

fast life cycle
lots of seeds
can be transformed
first plant genome fully sequenced

genotype + _________________ + environment = ?

genotype + epigenetic interactions + environment = phenotype

epigenetic interactions

how available the DNA is to get expressed

RNA polymerase I

transcribes rRNA
enzyme responsible for copying a DNA sequence into an RNA sequence

RNA polymerase II

transcribes mRNA

transcription factors

proteins that initiate and regulate the transcription of genes (Controls gene expression)

genes can only be expressed if it is available to what

available to RNA polymerase

RNApol moves down which strand

the template strand