Biology - 90928 - 1.4 Flashcards
Does a plant produced by sexual reproduction have the same or different genetic makeup from it’s parent plants?
Different
What is the male gametes in plants?
Pollen, formed by meiosis in the anther of the flower
What is the female gametes in plants?
Ovules, formed in the ovary.
Anther
The pollen producing part of a plant
What is the transfer of pollen from anther to stigma called?
Pollination
Can pollination occur between plants of different species?
No
Cross-pollination
Transfer of pollen from anther in one plant, to the stigma of another plant (same species)
Self-pollination
Transfer of pollen in the same plant.
Insect pollination
An insect transfers the pollen. The plants have brightly coloured flowers and nectar to attract insects, and pollen that sticks to the insect.
Wind pollination
Pollen is blown from anther to stigma. Plants produce lots of light, smooth, round pollen.
What happens when pollen lands on a stigma of the same species? (Fertilisation).
Chemicals on the stigma cause the pollen to grow. The pollen grows a thin tube down the style and into the ovary, where the genetic material in the pollen joins with the genetic material of an ovule.
After fertilisation, the ovules in the ovary develop into..
Seeds
Testa
Outer covering of a seed, also called the seed coat
Radicle
First part of a seedling (a growing plant embryo) to emerge from the seed during the process of germination. The radicle is the embryonic root of the plant, and grows downward in the soil (the shoot emerges from the plumule).
Plumule
The young shoot of a plant embryo above the cotyledons, consisting of the epicotyl and often of immature leaves.
Cotyledons
A leaf of the embryo of a seed plant, which upon germination either remains in the seed or emerges, enlarges, and becomes green.
Micropyle
A small opening in the surface of an ovule, through which the pollen tube penetrates, often visible as a small pore in the ripe seed.
After fertilisation, what does the ovary of a flower develop into?
A fruit
Asexual reproduction as called?
Vegetative reproduction
Does a plant produced by asexual reproduction have the same or different genetic makeup as it’s parent plant?
Same.
Can a plant reproduce both sexually and asexually?
Yes
Can new plants grow from part of a plant?
Yes, in some species. E.g dandelions plants are able to grow from parts of a broken main root.
What are cuttings, tubers, rhizomes, runners, bulbs, and corm examples of?
Asexual repreoduction
Photosynthesis
Process by which plants make glucose from carbon dioxide and water, using chlorophyll (green pigment) and energy from light.
How is glucose stored by plants?
As starch
Chlorophyll
Green pigment
Photosynthesis equation
CO2 + water (plus chlorophyll and light) -> glucose + O2
Main plant structure involved in photosynthesis
Leaves
Properties of leaves that help them carry out photosynthesis efficiently?
Thin (gases don’t travel far), flat (large surface area to trap light), arranged strategically, green because of chlorophyll, covered in waxy cuticle layer to stop leaf drying out.
Label parts of a leaf
dd
How can we test for starch in a leaf (to indicate photosynthesis has been occuring)?
- Boil leaf in water to remove waxy cuticle
- Boil leaf in meths to remove chlorophyll
- Wash leave with boiling water
- Add 3-4 drops of iodine solution to test for starch
- A blue-black colour indicates starch is present
What factors increase photosynthesis
More CO2, more light intensity, more temperature (to a point), enough magnesium, enough water, changing wavelength of light (chlorophyll absorbs all colours of light except green)
Broadly, what does growth in plants do?
Increases height, increases width, produces more leaves, replaces tissue
Germination
Growth of an embryo plant within a seed
Dormant seeds
Inactive seeds that can lie dormant for years until the right conditions develop
How does germination begin and what is required for germination?
The seed takes in water. Needs water, oxygen, and a suitable temperature.
During germination, what grows first, followed by what, and then what happens?
The root of the embryo (the radicle) grows, then the shoot (or plumule), then lateral roots begin to form, then the embryo uses nutrients stored in the seed to grow into a seedling.
What affects the germination of seeds
Water, oxygen, temperature, and sometimes light (but not always)
What 3 processes are linked to primary growth in plants?
Mitosis, elongation, differentiation
Mitosis
Cell division, occurs at growing points such as the apical meristem and root tips
Elongation
Occurs just behind the growing points - individual cells get bigger
Differentiation
Occurs slightly further away from the growing points. Cells change from a general shape to the shape they will be to carry out their function.
Secondary growth
Plants that live longer than 1 or 2 years grow wider by secondary growth. It occurs in the cambium layer betwen the xylem and phloem in the vascular tissue
During secondary growth, what happens to cells in the cambium layer?
They divide to form new cells. New cells formed on the outside of the cambium differentiate to become phloem. Older phloem cells become blocked and are no longer able to transport nutrients - they become bark. Cells formed on the inside of the cambium become xylem. Older xylem cells can no longer transport water and minerals - they become wood.
Annual rings
Xylem cells formed at differnt parts of the year are different sizes, which gives the wood a pattern of light and dark bands.
Why do plants often grow well in spring?
Greater amount of water, suitable temperature result in larger xylem vessels being produced.
Can the amount of nutrients in the growth media affect growth?
Yes. Nutrients affect growth and photosynthesis (e.g magnesium needs to be present).
4 parts of a flower
Sepals, petals, stamen (male), carpel (female)
How do leaves turn into flowers?
When conditions are suitable and nutrients available, at least four genes (A, B, C, D) are expressed in cells that become flowers. The four genes work together to produce the four parts of the flower.
