Lecture 4 Flashcards
something that should, or does contain one seed
fruit
reproductive structure of conifers?
cones
reproductive structure of flowering plants?
flowers
microgametophyte in conifers?
pollen
nourishing embryo in conifers?
megagametophyte
microgametophyte in flowering plants?
pollen
nourishing embryo in flowering plants?
endosperm
how many cells are the conifers megagametophyte?
many cells
how many cells are flowering plants megagametophyte?
8 nuclei, 7 cells
what is special about conifers seeds?
they are naked
Parts of the shoot system?
nodes, branch, auxiliary bud, leaf, internode region
Place on shoot where leaves emerge, sometimes branches
node
originally bud, that can remain dormant until it wants to grow
branch
small bud
auxiliary bud
contains blade and petiole
leaf
space on shoot between nodes
internode region
what does the root system consist of?
taproot
lateral roots
glucose chain
cellulose
adjacent, parallel cellulose molecules (polysaccharide), rope-like
cellulose microfibers
thin, in all cells; all plants have (except sperm and sea plants)
primary plant cell wall
thicker, only in some cells; some plants (helps with strength)
secondary plant cell wall
what are plant cell walls mostly composed of?
cellulose
some functions of plant cell walls?
Determines and maintains cell shape as plant cell (and membrane with it) within cell wall can expand and contract
Provides support, mechanical strength: allowing plants to get tall, compete for light, hold out thin leaves
Prevent membrane from bursting, because cells will continue swelling w/o cell wall
Control rate and direction of cell grow
Form shape of plant, determines how plant can grow
Physical barrier to threats like:
pathogens
water in suberized (waxy) cells, some cell walls aren’t waxy
Remember wall is porous and allows passage of small molecules*
Carb storage, which the cell can take back and use
What are the three types of polyssacharide in cell walls?
cellulose
cross-linking glycans (hemicellulose)
pectin
What does hemicellulose/ cross linking glycans do?
bond with cellulose
what is the function of pectin in the cell wall?
holding everything together like glue
: material of pectic substances which holds adjacent cells together by acting like a glue
middle lamella
Was the secondary or primary cell wall made second?
the secondary cell wall was made second
How was the secondary cell wall made?
the membrane inside the cell makes the cell walls
makes primary
primary pushed outwards
secondary made
why are there two cell walls
support, protection
the connections between the cells. Extensions between cells where membrane is continuous
plasmodesmata
(cell)
Outermost coating of all land plants (single sheet/layer)
epidermal cells
function of epidermal cells
waterproofing
protection from bacteria
wax and epidermal cells make the ____
cuticle
function of the cuticle
protects against:
water loss
UV radiation
pathogens
cell type: Functions, usually performed as a unit of these cells (accomplish things in groups), general cell
parenchymal cells
function of parenchymal cells
photosynthesis
storage
secretion
do parenchymal cells have a secondary cell wall?
not usually
When do parenchymal cells divide?
at maturity
cell type:
Support, especially of young and growing organs
- uneven primary cell wall
collenchymal cells
do collenchymal cells have a secondary cell wall?
no
are collenchymal cells alive at maturity? what do they do at maturity?
yes; they elongate at maturity
cell type:
Support, protection of tissues no longer elongating/ getting longer because they are hard cells with thick secondary wall that has polymer lignin in it.
- has 2 forms
sclerenchyma cells
are sclerechyma cells alive at maturity? can they elongate at maturity?
probably dead at maturity; cannot elongate at maturity
do sclerenchyma cells have a secondary wall?
yes, a thick secondary wall
what are the two types of sclerenchyma cells?
fibers
sclereids
water conducting cells of xylem?
tracheids and vessel elements
_____ have tracheids?
all vascular plants
____ have vessel elements
flowering plants
are xylem cells alive at maturity?
no
What is special about xylem cells second wall?
it is lignified; woody
how does water flow through xylem cells
tracheids: through the pits
vessel elements: through tops and bottoms
openings in cell walls between cells
pits
order of programmed cell death/apotosis
1) Cytoplasmic streaming
2) Secondary cell wall formed
3) Vacuole implodes
sugar conducting cells of the phloem?
sieve elements
are sieve elements alive at maturity?
yes
what are special about sieve elements?
they have companion cells
Ultimate source of all parts of mature sporophyte (organs, ect)
Undifferentiated
Retain “forever” the ability to divide (similar to stem cells)
meristems
Roots AM and shoot AM
Primary growth of plant tissue systems
apical meristems
Vascular cambium and cork cambium
Secondary growth
lateral meristems
what do lateral meristems enable the plant to become?
woody
What are the three intermediate meristems?
procambium
protoderm
ground meristem
what does the procambium make?
vascular tissue
what does the protoderm make?
dermal tissue
what does the ground meristem make?
ground tissue
what is the epidermis?
single layer of epidermal cells; covered by cuticle
