PL SCI 221 - MIDTERM EXAM QUESTIONS AND
ANSWERS LATEST UPDATE
middle lamella
Non-living area between adjacent cells and is filled with Ca2+ and Mg2+ pectates
(pectin; a complex set of polysaccharides) which cement adjacent cells together. Fruit
ripening!
pectinases
enzyme that degrades pectin during the ripening process; breaks down pectin resulting
in fruit softening
flavr savr
slow down softening process by limiting pectin breakdown; so they can leave on the
vine longer and have a better tasting tomato
plasma membrane (plasmalemma)
right up against the cell wall, semi permeable.
plasmodesmata (pores)
occur through the cell wall that allow a continuum of cytoplasm and membrane material
from one cell to another
symplast
continuum of living material; minerals and metabolites can be transported throughout
the plant without ever leaving the cytoplasm
apoplast
non-living portions of plant tissue, ex. middle lamella, dead xylem vessels
unsaturated fat
at least one double bond
saturated fat
carbons are all single bonded with hydrogen
Parts of the cell membrane (%)
lipids (40%), proteins (40%) and carbohydrates (20%)
Fluidity in membrane
lipids are NOT covalently linked, responsible for chilling resistance
Proteins
enzymes, both peripheral and integral
Senescence
the condition or process of deterioration with age
liquid crystalline state
the membrane is fluid, proteins can move, the plant is in it's ideal state. Enzymes can
perform functions
phase transition
membrane changes from liquid crystalline to solid gel phase, most membrane activities
are brought to a standstill and permeability increases
critical temperature
differential sensitivity of membranes to cold (warm vs cool season crops)
Cool season crops
,more unsaturated fatty acids, creating kinks, preventing tight packing
Cost of double bonds
the right enzymes, risk of oxidation
hardening-off treatment
slowly exposing the plant to cooler temperatures
Nucleus
surrounded by a nuclear envelope that is a porous, double membrane. It contains: the
chromosomes (genetic material of the cell), one or more nucleoli (dark staining masses
made up of protein and nucleic acids; involved in rRNA synthesis)
Endoplasmic reticulum
3-D network of continuous tubules and flattened sacs that course through the cytoplasm
and connect to the nuclear envelope (distinct from the plasma membrane)
Ribosomes
composed of protein and RNA; serve as the site of protien synthesis
Rough ER
ER membrane tubes studded with ribosomes on its surface giving it a rough
appearance under the microscope.
Smooth ER
Er membrane tubes that are smooth (no ribosomes on the surface)
ER functions
synthesizing proteins, lipids, regulating calcium, linked to lumen (tubes throughout
organism's cells)
Golgi apparatus (dictyosome)
saucer-shaped stacks of membranes. The ends of the membranes appear swollen or
ballooned and give rise to vesicles by pinching them off the main structure
Dictyosome functions
assembling complex carbohydrates for the cell wall; synthesizing carbohydrate side
chains for glycoproteins in the membrane, cell wall and vacuole
Mitochondria
organelles surrounded by a double unit membrane. Centres of respiration in the cell and
are responsible for converting food (sugars) into energy rich compounds (ATP) to
support all the metabolic activities of the cell
Vacuoles
fluid-filled compartments enclosed by a membrane called the tonoplast. More than 30%
of the cell volume. Recycling bin. pH regulation
tonoplast
encolses the vacuole, single-unit membrane
low light conditions
chloroplasts arrange themselves to be on the top of the cell in order to absorb the most
amoount of light
high light conditions
chloroplasts arrange themselves on the sides of the cell to absorb less light and avoid
photodamage
stroma
fluid surrounding thylakoid; where dark reactions occur
Light rxns
, capture of light energy and its conversion to chemical bond energy (ATP and NADPH)
Dark rxns
enzymatic fixation of CO2 into carbohydrate utilizing the ATP and NADPH from the light
rxns
Gymnosperm
cone bearing plants, naked seed; more primitive
Angiosperm
flowering plants, enclosed or vesseled seed; divided into monocotyledons and
dicotyledons
Flowering plants consist of
above ground shoot system and below ground root system
above ground shoot system
stems, leaves, buds, flowers, fruits
7 Dicot characteristics
2 seeds, 4-5 floral parts, netlike leaf viens, 3 pores in grain, vascular bundles arranged
as a ring, primary taproot, many are woody
7 monocot characteristics
1 seed, 3 floral parts, parallel array of leaf veins, 1 pore in grain, vascular bundles
distributed around tissue of stem, fibrous root system, few are woody
meristem
a tissue that contains actively dividing cells (most tissues of a plant are no meristematic)
4 types of meristems
apical, axillary, lateral, intercalary
Apical meristem
triggers the growth of new cells in young seedling at the tips of roots and shoots and
forming buds
Leave parts
blade (lamina), stalk (petiole) and attached to the stem at the node
Axillary meristem
gives rise to branches, between the leaf petiole and the stem; may remain dormant
under hormonal control
Lateral meristem
consists of vascular cambium and cork cambium; present only in dicots
Vascular cambium
produces additional vascular tissue in the secondary xylem and secondary phloem;
generated by the pericycle
Cork cambium
produces outer bark and adds to stem/root girth
Intercalary meristem
present only in monocots, between 2 differentiated tissues. Facilitates longitudinal
growth of plant organs independent of the apical meristem. Responsible for leaf growth
in grasses
Lamina
blade
Petiole
stalk
ANSWERS LATEST UPDATE
middle lamella
Non-living area between adjacent cells and is filled with Ca2+ and Mg2+ pectates
(pectin; a complex set of polysaccharides) which cement adjacent cells together. Fruit
ripening!
pectinases
enzyme that degrades pectin during the ripening process; breaks down pectin resulting
in fruit softening
flavr savr
slow down softening process by limiting pectin breakdown; so they can leave on the
vine longer and have a better tasting tomato
plasma membrane (plasmalemma)
right up against the cell wall, semi permeable.
plasmodesmata (pores)
occur through the cell wall that allow a continuum of cytoplasm and membrane material
from one cell to another
symplast
continuum of living material; minerals and metabolites can be transported throughout
the plant without ever leaving the cytoplasm
apoplast
non-living portions of plant tissue, ex. middle lamella, dead xylem vessels
unsaturated fat
at least one double bond
saturated fat
carbons are all single bonded with hydrogen
Parts of the cell membrane (%)
lipids (40%), proteins (40%) and carbohydrates (20%)
Fluidity in membrane
lipids are NOT covalently linked, responsible for chilling resistance
Proteins
enzymes, both peripheral and integral
Senescence
the condition or process of deterioration with age
liquid crystalline state
the membrane is fluid, proteins can move, the plant is in it's ideal state. Enzymes can
perform functions
phase transition
membrane changes from liquid crystalline to solid gel phase, most membrane activities
are brought to a standstill and permeability increases
critical temperature
differential sensitivity of membranes to cold (warm vs cool season crops)
Cool season crops
,more unsaturated fatty acids, creating kinks, preventing tight packing
Cost of double bonds
the right enzymes, risk of oxidation
hardening-off treatment
slowly exposing the plant to cooler temperatures
Nucleus
surrounded by a nuclear envelope that is a porous, double membrane. It contains: the
chromosomes (genetic material of the cell), one or more nucleoli (dark staining masses
made up of protein and nucleic acids; involved in rRNA synthesis)
Endoplasmic reticulum
3-D network of continuous tubules and flattened sacs that course through the cytoplasm
and connect to the nuclear envelope (distinct from the plasma membrane)
Ribosomes
composed of protein and RNA; serve as the site of protien synthesis
Rough ER
ER membrane tubes studded with ribosomes on its surface giving it a rough
appearance under the microscope.
Smooth ER
Er membrane tubes that are smooth (no ribosomes on the surface)
ER functions
synthesizing proteins, lipids, regulating calcium, linked to lumen (tubes throughout
organism's cells)
Golgi apparatus (dictyosome)
saucer-shaped stacks of membranes. The ends of the membranes appear swollen or
ballooned and give rise to vesicles by pinching them off the main structure
Dictyosome functions
assembling complex carbohydrates for the cell wall; synthesizing carbohydrate side
chains for glycoproteins in the membrane, cell wall and vacuole
Mitochondria
organelles surrounded by a double unit membrane. Centres of respiration in the cell and
are responsible for converting food (sugars) into energy rich compounds (ATP) to
support all the metabolic activities of the cell
Vacuoles
fluid-filled compartments enclosed by a membrane called the tonoplast. More than 30%
of the cell volume. Recycling bin. pH regulation
tonoplast
encolses the vacuole, single-unit membrane
low light conditions
chloroplasts arrange themselves to be on the top of the cell in order to absorb the most
amoount of light
high light conditions
chloroplasts arrange themselves on the sides of the cell to absorb less light and avoid
photodamage
stroma
fluid surrounding thylakoid; where dark reactions occur
Light rxns
, capture of light energy and its conversion to chemical bond energy (ATP and NADPH)
Dark rxns
enzymatic fixation of CO2 into carbohydrate utilizing the ATP and NADPH from the light
rxns
Gymnosperm
cone bearing plants, naked seed; more primitive
Angiosperm
flowering plants, enclosed or vesseled seed; divided into monocotyledons and
dicotyledons
Flowering plants consist of
above ground shoot system and below ground root system
above ground shoot system
stems, leaves, buds, flowers, fruits
7 Dicot characteristics
2 seeds, 4-5 floral parts, netlike leaf viens, 3 pores in grain, vascular bundles arranged
as a ring, primary taproot, many are woody
7 monocot characteristics
1 seed, 3 floral parts, parallel array of leaf veins, 1 pore in grain, vascular bundles
distributed around tissue of stem, fibrous root system, few are woody
meristem
a tissue that contains actively dividing cells (most tissues of a plant are no meristematic)
4 types of meristems
apical, axillary, lateral, intercalary
Apical meristem
triggers the growth of new cells in young seedling at the tips of roots and shoots and
forming buds
Leave parts
blade (lamina), stalk (petiole) and attached to the stem at the node
Axillary meristem
gives rise to branches, between the leaf petiole and the stem; may remain dormant
under hormonal control
Lateral meristem
consists of vascular cambium and cork cambium; present only in dicots
Vascular cambium
produces additional vascular tissue in the secondary xylem and secondary phloem;
generated by the pericycle
Cork cambium
produces outer bark and adds to stem/root girth
Intercalary meristem
present only in monocots, between 2 differentiated tissues. Facilitates longitudinal
growth of plant organs independent of the apical meristem. Responsible for leaf growth
in grasses
Lamina
blade
Petiole
stalk
