Define the term transpiration and explain the factors that can affect transpiration in a typical terrestrial plant.
-Transpiration is the loss of water vapor from the stomata in the leaves of plants.
-Temperature, humidity, light, and wind all affect transpiration.
-High temperatures increase evaporation rate of water.
-High humidity lowers the rate of water evaporatio
how do mineral ions in the soil move to the root through the soil
mass flow of water
how are fluids transported in the xylem and phloem
xylem away from the root only
Phloem away from the root and towards the root
what causes the stomata to close
presence of abscisic acid
Which plant hormone is responsible for the closing of the stomata
abscisic acid
what is the effect of abscisic acid on transpiration
it decreases transpiration by causing the stomata to close
Describe how water is carried by the transpiration stream
-Transpiration is water loss by evaporation
-Flow of water through xylem from roots to leaves is the transpiration stream.
-Evaporation from spongy mesophyll cells
-replaced by osmosis from the xylem
-through stomata
-water lost replaced from xylem
-water
List the ways in which mineral ions in the soil move into the root
Diffusion- Flow down their concentration gradient into root.
Mass flow- Dissolved in water so move into the root with water.
Fungal Hyphae- Fungus covers young roots, providing larger surface area for absorption; symbiotic relationship between fungus and
Explain the process of mineral ion absorption from the soil into roots by active transport
The concentration of mineral ions inside the plant's roots is a lot higher than that found in the soil. Therefore, mineral ions have to be transported into the roots via active transport. Protein pumps exist in the plasma membranes of root cells. There ar
Outline the role of the phloem in active translocation of sugars (sucrose) and amino acids from source (photosynthetic tissue and storage organs) to sink (fruits, seeds, roots)
Organic molecules (sugars, amino acids) move from their source (photosynthetic tissue or storage organs) into a tube system called the phloem
Sugars are transported as sucrose (because it is soluble but metabolically inert) in the fluid of the phloem (cal
Draw and label plan diagrams to show the distribution of tissues in the stem and leaf of a dicotyledonous plant
...
Outline three differences between the structures of dicotyledonous and monocotyledonous plants
Seed cotyledons: monocots have one cotyledon whereas dicots have two cotyledons
Leaves: monocots have parallel veins whereas dicots have net-like veins
Vascular tissue in stems: monocots have scattered vascular bundles whereas dicots have vascular bundles
Explain the role of auxin in phototropism as an example of the control of plant growth
-auxin is a plant hormone;
produced by the tip of the stem/shoot tip;
-causes transport of hydrogen ions from cytoplasm to cell wall;
-decrease in pH;
-makes cell walls flexible;
-auxin makes cells enlarge/grow;
-gene expression also altered by auxin to p
Draw and label a diagram showing the external and internal structures of a named dicotyledonous seed
...
Y and one of its functions?
Xylem, mechanical support
Structure shown?
Dicotyledon stem
What part of the human body similar to spongy mesophyll
Alveoli in the lungs
Main structures in a bulb and their function
Swollen leaf bases for food storage
Two types of meristems found in plants
Apical and lateral
Two methods by which terrestrial plants support themselves
Thickened cellulose in walls and lignified xylem.
Compare growth due to apical and lateral meristems in dicotyledonous plants.
-meristems are regions where cells continue to divide and grow, often throughout the life of the plant
-Both apical and lateral meristems rely on totipotent cell divisions for growth.
-apical meristems are located at the tip of the root and stem,add verti
State that dicotyledonous plants have apical and lateral meristems
Apical meristems are sometimes referred to as primary meristems
Lateral meristems are somethimes referred to as cambium
Meristems generate new cells for growth of the plant
Identify modifications of roots, stems and leaves for different functions: bulbs, stem tubers, storage roots and tendrils'
-Many plants have modified roots, stems, and leaves in order to help them survive in different environments.
Storage roots- Underground roots cells that are modified to store large quantities of water and carbohydrates. For example carrots and beats.
Stem
Explain the relationship between the distribution of tissues in the leaf and the functions of these tissues.
waxy cuticle: secreted by epidermis, covers top and bottom leaf surfaces, reduces water loss, as it is impermeable to water
epidermis (upper and lower): cover surfaces of leaf, secrete cuticle, protect against infection, conserves water
palisade mesophyll
Explain the functions of the different tissues of a leaf
cuticle (produced by epidermis) prevents water loss
epidermis protects cells inside the leaf
stomata (in epidermis) for gas exchange
palisade parenchyma / mesophyll / layer for photosynthesis
spongy parenchyma / mesophyll / layer for photosynthesis
air sp
Outline the adaptations of plant roots for absorption of mineral ions from the soil
mineral ions are absorbed by active transport;
large surface area;
branching (increases surface area);
root hairs;
root hair cells have carrier protein/ion pumps (in their plasma membrane);
(many) mitochondria in root (hair) cells;
to provide ATP for acti
Describe the process of mineral ion uptake into roots.
absorbed by root hairs / through epidermis
root hairs increase the surface area for absorption
uses active transport / uses ATP / uses energy
use of proteins / pumps to move ions across membrane
against concentration gradient / diffusion gradients into ce
Explain how abiotic factors affect the rate of transpiration in a terrestrial plant.
less transpiration as (atmospheric) humidity rises
smaller concentration gradient ( of water vapour)
more transpiration as temperature rises
faster diffusion / more kinetic energy (of water molecules)
faster evaporation (due to more latent heat available)
Explain how wind affects the rate of transpiration from a leaf.
wind blows air / water vapour away from the leaf
water vapour that has diffused out of the stomata is carried away
low humidity maintained near the leaf without wind air becomes saturated
large water concentration gradient between inside and outside the l
Outline adaptations of xerophytes.
xerophytes are plants that live in dry conditions;
reduced leaves/spines to prevent water loss (by transpiration);
rolled leaves to prevent water loss / stomata on the inside / sunken stomata;
thick waxy cuticle/hairs on leaves to prevent water loss (by t
Outline the role of the phloem in the active translocation of biochemicals.
living tissue
composed of companion cells / sieve tube members
companion cells involved in ATP production
sucrose / amino acids / assimilate / products of photosynthesis transported
bi-directional transport
source / leaves to sink / fruits / roots /storag
Outline how the root system provides a large surface area for mineral ion and water uptake by means of branching and root hairs (Long)
Plants take up water and essential minerals via their roots and thus need a maximal surface area in order to optimise this uptake
The monocotyledon root has a fibrous, highly branching structure which increases surface area for maximal absorption
The dico
Explain the process of water uptake and transport by a plant.
roots have a large / increased surface area (in relation to their rohme); root hairs increase the surface area;
water is absorbed by osmosis;
solute concentration inside the root is higher than in the soil / outside; due to active transport of ion into th
Draw and label a diagram showing the structure of a dicotyledonous animal-pollinated flower
Bio book pg. 431 + Ovule, Receptacle, and Pedicel
Distinguish between pollination, fertilisation and seed dispersal
Pollination: The transfer of pollen grains from the anther to the stigma (usually of another plant), often facilitated by animals, wind or water movement
Fertilisation: Fusion of the male gamete nuclei (in the pollen grain) with the female gamete (in the
Draw and label a diagram showing the external and internal structures of a named dicotyledonous seed
Bio book pg. 434
Explain the conditions needed for the germination of a typical seed
Germination is the process by which a seed emerges from a period of dormancy and starts to sprout
For germination to occur, a seed requires a combination of:
Oxygen: For aerobic respiration (need ATP in order to grow)
Water: To metabolically activate the
Outline the metabolic processes during germination of a starchy seed
The first step in the germination process is the absorption of water, which causes gibberellin - or gibberellic acid (GA) - to be produced
Gibberellin causes the synthesis of amylase, which breaks down starch into maltose
Maltose is transported to the emb
Explain how flowering is controlled in long day and short day plants, including the role of phytochrome
Flowering is controlled by phytochrome, which is affected by light (photoperiodicity)
Phytochrome exists in two forms:
A red (Pr) form absorbs red light (~660 nm) and is converted into a far red form (Pfr)
A far red (Pfr) form absorbs far red light (~730
Mechanisms involved in water transport in the xylem can be investigated using apparatus & materials that show similarities in structure to plant tissues
Water transport in the xylem can be modeled using simple apparatus including blotting or filter paper, porous pots, and capillary tubing.
Experimental methods for measuring phloem transport rates using aphid stylets & radioactively-labelled CO2 were only possible when radioisotopes became available
Aphids - exudates (substance secreted by an insect/plant) from their stylets
Autoradiography of Carbon - track the flow of C (usually in the form of sucrose) through the plant
Developments in scientific research follow improvements in analysis deduction
Understanding the role of plant hormones
Darwin & Went's experiment with canary grass
Darwins: observed coleoptiles (initial section of stem) & found that they could bend the plant towards a unidirectional light source
Went: isolated the plant growth horm
Knowing that the majority of angiosperms depend on pollinators for reproduction has led to the protection of entire ecosystems rather than individual species
The Saguaro cactus = keystone species in Sonoran desert
Affect red-tailed hawks, gilded flickers, gila woodpeckers, elf owls, purple martins & other birds
Birds will eat the fruit and disperse seeds
Pollinated by long-nosed bats & mexican long-tongued bat