Transcript Opening Questions

• Identify four phyla of plants ?
• Which of these phyla are vascular?
Questions
• HL Question
Compare two types of meristem found in
plants.
HL -- Compare the growth found at the
apical & lateral meristems
Apical Meristems
• Found at the rips of
roots and shoots
• Responsible for primary
growth
• Extensions of roots and
shoots
• Growth of new organs
and developing basic
shape of plant
Lateral Meristem
• Found in the cork
cambium and vascular
cambium
• Responsible for primary
secondary growth
• New vascular tissue and
producing woood
Outline two differences in structure between
monocotyledonous and dicotyledonous plants.
(2)
Structure
Monocotyledonous
Dicotyledonus
leaf
parallel veins
branched (net of) veins;
seed
one cotyledon
two cotyledons;
floral parts in multiple of
3
scattered vascular
bundles
floral parts in multiple
of 4 or 5;
ring of vascular bundles
around central pith;
adventitious roots
branched tap roots;
flower
stem
root
Monocot/ Dicot Scavenger Hunt
• Using a camera phone finds as many examples
of Dicotyledon & monocotlyledon LEAVES and
FLOWERS as you can.
• EACH leaf & flower MUST BE A DIFFERENT
SPECIES OF PLANT.
• You have 10 minutes. ….
Plant Adaptation
PowerPoint
• Name of adaptation
• Picture of Adaptation
• Description of how function relates to
structure
Draw the diagram below, label the
vascular cambium, secondary xylem,
secondary phloem and cork cambium
Draw the diagram of a dicot stem below and label the following
features: Cortex, epidermis, pith, cambium, xylem, phloem,
vascular bundle
• Draw a diagram to the
left and in your
diagram of a
dicotolydenous stem
label the xylem,
phloems, cambium,
vascular bundle
Identify the labels A-F and define their
function
Which one is a monocot and which
one is a dicot?
Which one is a monocot and which
one is a dicot?
Which one is a monocot and which
one is a dicot?
DICOT STEM ? MONOCOT STEM?
CONTROL OF PLANT GROWTH.
• IDENTIFY THE HORMONE THAT CAUSES
PLANTS TO BEND TOWARDS LIGHT
• IDENTIFY THE NAME OF THE GROWTH/
TROPISM OF PLANTS TOWARDS LIGHT
• IDENTIFY WHERE AUXIN IS PRODUCED.
• WHERE ON A STEM DOES AUXIN
CONCENTRATE (SUNNY SIDE OR DARK SIDE)
• AT THE CELLULAR LEVEL WHAT DOES AUXIN
DO
Opening Questions
HIGH LEVEL
• Outline the adaptations of plant roots for absorption of
mineral ions from the soil. (5)
Outline the adaptations of plant roots for absorption of
mineral ions from the soil. (5)
• Large surface area of roots allow for rapid absorption of
mineral ions;
• Branching of roots increases surface area; root hairs of
epidermal cells increase surface area;
• Mineral ions are absorbed by roots via active transport
through membranes of the root hair cells
• root hair cells have carrier protein/ion pumps (in their
plasma membrane);
• there are many mitochondria in root (hair) cells
• The mitochondria in root hair cells provide ATP for active
transport ;
• Roots have connections with fungi in the soil/fungal hyphae
which increase absorption of minerals from soil;
• Describe the process of water uptake and
movement in roots.
• (6)
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oot hair / root branching / cortex cells add surface area;
plants actively transport minerals from soils;
creating a solute gradient within the root;
that draws water into the root through osmosis;
(most) water travels through the apoplastic pathway / through cell
walls;
movement is by capillary action;
some water travels via the symplastic pathway / through cell
cytoplasm (and plasmodesmata);
apoplast water cannot bypass Casparian strip of endodermis;
enters xylem within vascular cylinder / stele;6 maxPlus up to [2] for
quality)[20]
• Explain the process of water uptake and
transport by a plant.(Total 8 marks)
Explain the process of water uptake and transport by a
plant.(Total 8 marks)
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Roots have a large / increased surface which allows for rapid uptake of water
Root hairs increase the surface area;
water is absorbed in roots by osmosis;
Water travels into roots cells from soil because solute concentration inside the root is
higher than in the soil / outside;
Solute concentration is higher in roots than soil b/c solutes (mineral ion) are actively
transport into the root;
Water travels through the cortex cells of roots through apoplastic and symplastic
pathways
apoplastic route/ pathway of water is through the cell walls of the root cells(and
intercellular spaces);
symplastic route of water is through the cytoplasm (and plasmodesmata) of roots
cells;
Water is carried up stem by xylem (vessel elements / tracheids);
Before entering the xylem water has to pass through cytoplasm of endodermis /
Casparian strip blocks water;
water movement up the xylem due to pulling force / transpiration pull from leaves;
water movement up the xylem is also due to cohesion between water molecules;
Outline the adaptations of plant roots for absorption of
mineral ions from the soil. (5)
5. Mineral ions are absorbed by active transport;
6. For example, root hair cells have carrier protein/ion
pumps (in their plasma membrane)
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which allows them to pump H+ out to displace cations in the
soil and creates a electro-chemical gradient (membrane
potential) between inside of the cell and outside. This
membrane potential provides energy to get the cations to be
absorbed by the root cells via facillated diffusion in carrier
proteins (similar to chemiosmosis in respiration and
photosynthesis);
Ions pumps allow for specific cation minerals to be pumped
(actively transported) inside the plant cell
7. And (many) mitochondria in root (hair) cells
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Provides energy (ATP) to allows hydrogen ions to be actively
pumped out of cell via ion pumps and to allow ions to be
actively pumped in via specific ion pumps;
Outline adaptations of xerophytes. (4)
Outline adaptations of xerophytes. (4)
• xerophytes are plants that live in dry conditions;
• Xerophytes have reduced leaves/spines to prevent water
loss (by transpiration);
• They have rolled leaves to prevent water loss / stomata on
the inside / sunken stomata;
• They have thick waxy cuticle/hairs on leaves to prevent
water loss (by transpiration);
• They have reduced stomata to prevent water loss (by
transpiration) / stomata on one side of leaf;
• They have deep/widespread roots to obtain more
water; special tissue for storing water;
• They have alternative forms of photosynthesis such as CAM
where they take in carbon dioxide at night via their open
stomatas to prevent water loss
• Outline the role of phloem in active
translocation of sugars from source to sink.
(6)
• Translocation is the transport of sugar from photosynthetic tissue (leaves)
to some other organ (i.e. roots/ buds/ stems/ seed/ fruits) for sugar
storage.
• Sugar/ sucrose is transported through the phloem.
• The phloem is made up of living cells called sieve tube members and
companion cells.
• Sucrose is loaded into sieve tubes by the companion cells via active
transport.
• An increase in sucrose concentration in sieve tube cells cause water to
diffuse into phloem via osmosis,
• This sucrose and water inside the phloem causes a positive pressure which
cause phloem sap (water and sugar solution) to move in the phloem
towards the sink/ organ of sugar storage.
• At the sink, sucrose is actively transported into sink cells and is chemically
converted to starch.
• When sucrose leaves phloem and enters sink cells, water diffuses out of
the phloem and back to the xylem, and water is recycled.
IB ASSESSMENT STATEMENT
•9.3.1 Draw and label a diagram showing the structure of
dicotyledonous animal-pollinated flower and plants.
Copyright Pearson Prentice Hall
Flower structure
Stigma
Style
Ovary
Petal
Anther
Sepal
Filament
© 2008 Paul Billiet ODWS
Structure of Flowers
•Parts of a Typical Flower
Stamen
Stigma
Anther
Filament
Style
Ovary
Ovary
Petal
Sepal
Ovule
Copyright Pearson Prentice Hall
Carpel
IB ASSESSMENT STATEMENT
9.3.3 Draw and label a diagram showing the external and
internal structure of a named dicotyledonous seed. Know
the following location and function of the following
structures:
Copyright Pearson Prentice Hall
•Seed Structure
•a) Testa protects the plant embryo and the cotyledon food stores
•b) Radicle is the embryonic root
•c) Plumule is the embryonic stem
•d) Cotyledons contain food store for the seed
•e) Micropyle is a hole in the testa ( from pollen tube fertilisation) through which
water can enter the seed prior to germination
•f) Scar is where the ovule was attached to the carpel wall.
Copyright Pearson Prentice Hall
LE 38-8a
Seed coat
(Testa)
Radicle
(Embryo
root)
Copyright Pearson Prentice Hall
Embryo
Shoots
(plumule)
Cotyledons
Copyright Pearson Prentice Hall
• Explain how flowering is controlled in long-day
and short-day plants.
• (7)
• Flowering affected by light;
• Phytochrome exists in two (interconvertible) forms/Pfr and Pr;
• Pr (red absorbing/660 nm) converted to Pfr (far-red/730 nm absorbing) in red
or day light;
• sunlight contains more red than far red-light so Pfr predominates during the
day;
• There is a gradual reversion of Pfr to Pr occurs in darkness;
• Pfr is active form and Pr is inactive form;
• In long-day plants, flowering induced by dark periods shorter than a critical
length / occurs when day is longer than a critical length;
• When enough Pfr remains in long-day plants at end of short nights it will
stimulate flowering;
• Pfr acts as promoter of flowering in long-day plants;
• short-day plants induced to flower by dark periods longer than a critical
length/days shorter than a critical value;
• at end of long nights enough Pfr has been converted to Pr to allow flowering to
occur;
• Pfr acts as inhibitor of flowering in short-day plants;
• Explain the conditions that are needed to
allow a seed to germinate.
• (5)
Explain the conditions that are needed to allow a
seed to germinate. (5)
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water needed to rehydrate the seed;
gibberellin released / active after water absorbed;
gibberellin needed to produce amylase;
Amylase breaks down starch into maltose and then glucose.
Glucose is need to do cellular respiration to provide energy for
growth.
Oxygen needed for (aerobic) cell respiration;
warmth needed to speed up metabolism/enzyme activity;
warmth indicates that it is a favourable season for
germination/spring;
some seeds need a cold period to stimulate germination;
some seeds need fire to stimulate germination;
some seeds need to pass through an animal (gut) to stimulate
germination;
Water movement
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Symplastic:
Water moves from cell to cell
Apoplastic:
Water moves via cell walls & extra cellular
spaces
Water Transport into the Roots
• Cells are usually
interconnected via
plasmodesmata.
• Their plasma forms a
continuum (a
“symplast”).
Water Transport into the Roots
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Apoplastic transport is when water is transported between
cells through the extra-cellular space.
Three major processes that allow
mineral ions to pass from soil to root
1. Diffusion (simple & Facilliated) of mineral ion & mass
flow of water from the soil to the root
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When concentration of mineral is higher outside the root hair cells
Some minerals (i.e. Potassium) need protein channel to diffuse inside
roots cells (facillitated diffusion)
2. Aid provided by fungal hyphae
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Symbiotic relationship with a fungus…fungal filaments called hyphae increase
surface area between plant and soil minerals
3. Active transport
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Using ATP and protein pumps to bring ions in against their
conc. Gradient
Using ATP and protein pumps to pump H+ ions out to create a
electro-chemical gradient (chemiosmosis) and diplace positve
mineral ions on clay particles.
Uptake of Ions by the Roots – HOW?
• Root interception
– Root grows and intercepts ions
• Simple diffusion
– Ions move down their concentration gradient
– No energy expense by plant
– Example: K+
• Mass flow
– Bulk flow of water into the root “carries” ions to root
– Delivers N, Ca, Mg, S
• Active transport
– Ions move against their concentration gradient
– Requires a specific protein “pump” in the cell membrane
– Energy expense by plant
HL-- Describe how water is carried by the
transpiration stream.(7)
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Define Transpiration: transpiration is water loss (from plant) by evaporation;
Define Transpirational Stream: flow of water through xylem from roots to
leaves is the transpiration stream;
Describe Transpiration stream: Water evaporation from spongy mesophyll cells;
And (diffusion of water vapour) through stomata;
Is replaced by osmosis from the xylem;
water lost replaced from xylem / clear diagram showing movement of water
from xylem through cell(s) (walls) to air space;
water pulled out of xylem creates suction/low pressure/tension;
Low pressure causes transpiration pull results;
Due to hydrogen bonding/polarity of water molecules;
water molecules stick together/are cohesive;
xylem vessels are thin (hollow) tubes;
adhesion between water and xylem due to polarity of water molecules;
Adhesion and Cohension create continuous column/transpiration stream;
HL You will work in Four groups today
• Group 1: Give a written description & an annotated
diagram of how water moves from the soil to the
endodermis cells inside the root
• Group 2: Give a written description & an annotated
diagram of how water moves from the soil to the
endodermis cells to the stomata of the leaves.
• Group 3 : Give a written description & an annotated
diagram how and why the stomata opens and closes.
• Group 4: Give a written description and an annotated
diagram identifying what factors affect the rate of
transpiration and describe how and explain why they affect
transpiration rate
HL
• 1. Describe the structure of phloem.
• 2. explain how sugar moves from source to
sieve
• 3. Explain how a positive pressure is created in
the phloem.
• 4. Explain how and why this positive pressure
diminishes
• 5. Explain why phloems are alive and xylem
cells are dead.
HL Question
• Plants develop brightly
coloured flowers to
attract animals. Which
process is directly assisted
by this adaptation?
• A. Seed dispersal
• B. Pollination
• C. Fertilization
• D. Germination
SL Question
• Distinguish between
fibrous and globular
proteins with reference to
one example of each
protein type.
HL question
• Explain how
phytochrome affects
long day plants
SL QUESTION
• Where in eukaryotic
cells is glucose broken
into pyruvate, to release
energy for use in the
cell?
• HL question
SL QUESTION
• Explain the effect of substrate
concentration on enzyme activity
• as substrate concentration
increases enzyme activity
increases;
• after a point, all active sites are
bound to substrate / all active
sites occupied; additional
substrate will not lead to a
greater rate of product formation
at this point;
• at high substrate concentration
enzyme reaches maximum
activity;
• active sites saturated;
labelled sketch-graph showing
above relationship;
.