5a - 5b Flashcards
Describe the basic structural parts of flowering plants and their functions,
Stem - structural support and hold phloem and xylem for transport of water and nutrients
Flower - reproduction
Fruit - seeds are held within
Branch - reaches the leaves into enlightened areas
Leaf - photosynthesis and gas exchange
Root - absorbs nutrients and water
Nodes - area where leafs leave the stem
Meristem - growth both laterally and vertically
(monocots and dicots) and how they differ with respect to tissue organisation in flowers, leaves, stems, roots, and seeds
m = Flower parts in groups of three
d = Flower parts in groups of five
m = Leaves are smooth and parallel veins
d = Leaves are palmate with netlike veins
m = Vascular bundles are scattered
d = Vascular bundles are ringed
m = Fibrous root system
d = Taproot system
m = One cotyledon in seed
d = Two cotyledons in seed
Describe how plants grow, where new tissues originate, and the differences between differentiated and meristematic cells; list the three main types of plant tissues and their function in plants
Apical meristems - located in the tips of roots and shoot they boost vertical growth.
Longitudinal meristems - located in the perimeter of the roots and shoots they boost lateral growth (girth).
Dermal - outer layer for protection (epidermis are the tightly packed layer with thin walled cells ) (Periderm are the replacement of epidermis tissue lie bark, roots)
Ground - packing of the plant parenchyma (store hormones, nutrients and photosynthesis), Collenchyma (flexible) and Sclerenchyma (support and strength).
Vascular - xylem (transport minerals up made from tracheids and vessel elements)and phloem (transports sugars and hormones in any direction (sieve tube elements and companion cells)
Describe the structure of leaves,
Leaves are made from the epidermis tissue with a waxy clear layer(cuticle). In between those layers are the mesophyll which holds the palisades layer (chloroplasts) and the spongy layer (Xylem and phloem which is the vascular bundle) the lower epidermis hold the stoma and guard cells.
the specialised leaves found in some plants
Cactus - The spines are the leaves and cannot photosynthesize
Onion - A bulb is mostly made from fleshy storage leaves.
Venus fly trap - Modified leaves are able to trap prey.
Bean - Tendrils are modified leaves
List the functions of stems, describe their external structure and the organisation of tissues in the dicot stem, describe the changes that occur in stem tissues as dicots grow, and list specialised stems found in some plants
Functions - support and transport for water, minerals and nutrients.
Structure - the central structural support line of the plant which all the branche originate from.
Tissue organisation - epidermal layer outside then the collenchyma just below. Then the vascular bundles are spread around in a ring-like shape with a cortex between. In the centre of the cell lies the pith.
Growth change - the vascular bundles begin to form a large ring and the cortex explands
Specialised stems - used for storage, vegetative reproduction, attachment/climbing
Example - strawberries have runner stems to increase vegetative spread and tendrils for climbing found in grapes
Compare the form of the monocotyledon and dicotyledon root,
Monocot vs dicot roots - dicot roots are specialised for storage (consider carrots) they carry most of the weight of the plant. Monocot roots are more similar to a network with its maximised surface area for absorbance.
the variety of functions carried out by roots, the organisation of tissues in roots and how this relates to their function
Function - anchor the plant for support, uptake water and minerals, store water and minerals
Tissue structure - broken into three parts, epidermis, vascular cylinder and the tip
Epidermis layer holds the epidermis exterior with the cortex just below, then the epidermis of the cortex.
Vascular cylinder holds the pericycle then inside that is the phloem, then the xylem
The tip is made of apical meristem and the root cap.
Explain the connections between root structure and function in the uptake of water and nutrients from the soil, the role of symbionts in plant nutrition, the cohesion-adhesion theory of water flow, and the mechanisms by which plants regulate stomatal opening
Uptake of nutrients - water is taken by osmosis and the nutrients are taken through active transport assisted by mycorrhizae fungi and nitrogen-fixing bacteria. The fungi increase surface area for the plant and the bacteria digest the nitrogen the the product is usable by the plant, hence symbiotic relationship.
Cohesion / adhesion theory - the sucktion of water from the leaves is built by the difference of atmospheric pressure built by the stomata causes the water to move due to the strong hydrogen bonds and the adhesion encourages the water to remain connected to the surface of the xylem and phloem.
Stomatal opening is regulated as the water move through osmosis k+ ions
Explain the mechanisms by which plants move sugars around the plant, including the role of sources and sinks
Sugars are moving from both roots and shoots (leaves)
Pressure flow hypothesis states that the sugar moves to sites of low concentration. The water absorbed creates a water slide (sink) (and pressure) for the sugar that is being pushed into the phloem towards the lower pressure, there is gets pushed to the lower concentrated areas known as the sinks
Describe how fruits and seeds develop from ovaries and ovules, and how seeds germinate and grow
Microspore mother cell (n) -> meiotic division -> 4 microspores -> each produce gametophyte -> two sperm cells in one pollen grain
The anther in the flowers produce pollen that is carried to the stigma via wind or pollinators. Double fertilisation is the process of germination (pollination) the pollen goes down the style into the ovule. One sperm fuses with the egg cell to create the embryo(2n), the other fusses with the central cell to form a triploid cell (endosperm) which provide nutrition for the germinating seed
Seed dispersal methods:
Consumption, Stuck on fur, Wind, Water
List the six major groups of plant hormones (auxins, gibberellins, cytokinins, ethylene, abscisic acid, and florigens) and their major role in plant growth responses; describe how auxin causes plant growth responses to light and gravity; explain how auxin and cytokinin together act to regulate branching in plants
Auxins - fruit development inhibits cell growth in roots and stimulates bending growth for shoots towards light
Gibberellins - stem elongation and processes like budding, flowing, fruit production, seed germination
Cytokines - inhibit lateral branch formation (roots) and stimulates branch formation (shoots)
Ethylene - (stress hormone) stimulates ripening of fruit
Abscisic acid - Helps with adaptive responses (inhibits root growth, stomatal closure
Foreigners - controls flowering timing
Auxin and cytokine front opposite function of the same system (growth) one growth only occurs when goethe of these hormones act, one inhibits the growth while the other stimulates growth.
Explain the range of flowering patterns of plants in response to changes in daylength, including the role of phytochrome and the concept of a biological clock
Photoperiodism controls the change of flowering in response to the environment based on the uninterrupted darkness. Photoperiodism is a pigment which absorbs either far red light or red light. Red Light is transformed into active photoperiodism; these transform back into inactive during the dark; the active form needs to reach a certain threshold (low) the plant will flower during the night
None - (daylight neutral)
Not dependent on light to flower
Long - day
Dependent on long light source (autumn)
Short - day
Flower when short light (spring)
Describe the role of flowers, list the role of the structures that comprise them (sepals, petals, stamens, and carpels), and describe the male and female gametophytes of angiosperms and the process of pollination
Sepals - protect the flower and bud
Petals - brightly coloured to attract pollinators
Stamen (androecium)- organ system which holds the filament (holds the anther) and anther (pollen producers)
Carpels (gynoecium) - organs system for female reproduction
- Stigma - entry site for pollen
- Style - tissue holding stigma with track for pollen
- Ovary - contains the ovules (egg ac) crucial in
Define alternation of generations, and describe the growth stages that characterise each generation
Alternation of generations - how the reproduction of some terrestrial plants rotate each generation between haploid -n (gametophyte generation) and diploid - 2n ( sporophyte generation )
Growth stages - Gametophyte generation - gametes ar epri=odcued and fuse to create zygotes. Sporophyte generation - zygote undergoes mitosis to create spores which then are released and undergoes mitosis into gamete
