Fertilization

Question 1

How does fertilization occur in plants

Answer 1

Fertilization
a pollen tube grows down the style carrying
the male gametes to fertilize the ovule inside the ovary
 the fertilized ovule develops into a seed and the ovary develops into a fruit

Question 2

what are pollen grains made by

Answer 2

stamen male part

Question 3

Why is the stigma sticky

Answer 3

so it can catch grains of pollen

Question 4

what is vegetative structures

how long does it last until

what does it switch into

what causes this

what is the main trigger

Answer 4

When a seed germinates, a young plant is formed that grows roots, stems and leaves called vegetative structures

 This vegetative phase last until a trigger causes the plant to switch into its
reproductive phase and produce flowers
 This happens because the meristems in the shoot start to produce parts of flowers
instead of leaves.
 The main trigger is the day length/dark period (although temperature can also play a
role)

Question 5

read this and actually understand dont just passive read

Answer 5

Parts of the Flowering Plant
 The flowers are the structures that allow for sexual reproduction in plants.
 male gametophytes (the pollen grains) are produced on the stamen (the male
part of the flower)
 stamens consist of a thin stalk called a filament and an anther, where the
pollen grains are formed
 female gametophyte is found within the pistil, the female part of the flower
 the pistil consists of three parts; the stigma, style and ovary.
 the style is the stalk connecting to the ovary, the stigma is the sticky part at the
tip of the style, and the ovary is where the egg cells are kept

Question 6

define mutualism

Answer 6

Mutualism an association between two organisms where both organisms benefit.

ex

Pollinators gain food from the nectar and plant gains a way to transfer its pollen to
another plant

Question 7

possible example for trigger for long/short day plants cuz it ties in with genetics

Answer 7

in long-day plants, the active form of the pigment phytochrome leads
to transcription of the flowering time gene (called FT gene). The
mRNA transcript of this gene then flows through the phloem to the
shoot apical meristem where it gets translated into the FT protein,
which leads to the activation of flowering genes to transform the leaf-
producing apical meristem into a reproductive meristem.

Question 8

Why is seed dispersal important

and what are the tactics

Answer 8

 seeds often travel long distances from the parent plant to help reduce competition
and spread the species

 dry and explosive (e.g. milkweed)
 fleshy and attractive for animals to eat (e.g. berries)
 feathery or winged to catch the wind (e.g. maple trees)
 hooked to cling to animals coats (e.g. burrs)

Question 9

how do flowers occur , short and long day plants

Answer 9

Photoperiodism
Only the active form of phytochrome (P fr ) can cause flowering, however its action differs in certain types of plants
 Plants can be classed as short-day or long-day plants – the critical factor in determiningtheir activity isnight
length
Short-day plants require the nights to reach a critical length to flower.
 In short-day plants,P fr inhibitsflowering and hence flowering requires low levels ofP fr (i.e. resulting from long
nights)
Long-day plants require the nights to be less than a critical length to flower.
 In long-day plants,P fr activatesflowering and hence flowering requires high levels ofP fr (i.e. resulting from short
nights)