Structure and Growth

9.1.2
Dicotyledonous
Monocotyledonous
3 pores per pollen grain
1 pore per pollen grain
Multiple of 4 or 5 for petals
Multiple of 3 for petals
Fibrous root system
Taproot (1 main root)
Vascular bundles in ring pattern
Randomly placed vascular bundles
Leaves’ veins parallel to each other
Leaves’ veins in a net pattern
9.1.3

  • Stoma: A pore that allows CO2 for photosynthesis to diffuse in and O2 to diffuse out.
  • Guard Cells: this pair of cells can open or close the stoma and so control the amount of transpiration.
  • Xylem: Bring water to replace losses due to transpiration, and inorganic minerals from the soil.
  • Phloem: Transports products of photosynthesis out of the leaf.
  • Upper Epidermis: a continuous layer of cells covered by a thick waxy cuticle. It prevents water loss from the upper surface even when heated by sunlight.
  • Lower Epidermis: is in a cooler position and has a thinner waxy cuticle.
  • Spongy mesophyll: consists of loosely packed rounded cells with few chloroplasts. This tissue provides the main gas exchange surface so must be near the stomata in the lower epidermis.
  • Palisade mesophyll: has many cylindrical cells with many chloroplasts. This is the main photosynthetic tissue and is located near the surface where the light intensity is highest.
9.1.4
Modification
Purpose
•Storage Roots
•Store large amounts of water and carbohydrates
•Tendrils (leaves or stems)
•Attachment and support
•Stem tubers
•Nutrient storage
•Bulb
•Nutrient storage

9.1.5

Dicotyledonous plants have apical and lateral meristems. Apical meristems are responsible for the growth of the root and the production of the leaves. Lateral meristems are responsible for extra thickening of the stem. Lateral meristems grow out laterally.

9.1.6
Meristems are the stem cells for the plant that allows it to grow indefinitely, as they absorb water and nutrients to do so. Apical meristems are the cells that are located in the stem and the roots of the plants. These meristems expand in the stem, and eventually become lateral meristems. Lateral meristems are the older stems that are closer to the outside of the stem. This is why the age of a tree can be determined by looking at the number of rings a tree has, as they are it's meristems.

9.1.7
Auxin has two functions. It causes the elongation of cells, and it causes cells to grow towards light. These functions work together because the side of a plant that gets less exposure to light produces more auxin than the light exposed side, which causes the cells on that side to elongate in the direction of the light. This allows the chlorophill in those cells to still take in light for use in photosynthesis even though they are in the shade.

Transport Module
9.2.1
The root system provides a large surface area for mineral ion and water uptake by means of branching and root hairs by being long, which draws more nutrients and water, by being more spread out, which results in having less competition for resources, being sturdy to survive through tough weather, and being spidery shaped. The ions get into the plants through the processes of diffusion, fungal hyphae, and active transport. Diffusion is when particles move from a high concentrated are to a low concentrated area. Fungal hyphae is when fungus on plants strech out to get food and water. Active transport is when ATP is used to transport substances between membranes.
9.2.2
There are three ways in which mineral ions in the soil move to the root. The first is down concentration gradients. The second is in the water that is also moving from the soil to the roots. The third has to do with fungal hyphae, which are long and branching fungi structures. The hyphae grows around the roots, the relationship between the roots and the hyphae being mutually beneficial, and the ions move from the soil to hyphae to the roots.

9.2.3
The process of mineral ion absorption from the soil into roots by active transport is through the hydrogen pump. ATP is used to move the hydrogen ions from the cytoplasm to the lysoome or from one areas to another. The protein being transported then changes shape in order for the hydrogen ion to fit through the membrane. The protein is conformation A when it receives an ion and turns into conformation B, under ATP, in order to release the ion to the other side.

9.2.4
Terrestrial plants support themselves by means of thickened cellulose, cell turgor and lignified xylem. Cellulose in its self is very strong, but when it is thickened, the plant stays upright with more strength. Cell Turgor is the pressure of water on the walls of the plant. This water is kept in vacuoles. The vacuoles can be filled to its max so that the plant can stay upright. Lignin, which is in the xylem, fills the empty spaces within a plant, and binds different parts of the plant together to create strength.

external image lignin_h.jpg

Transpiration
9.2.5
Transpiration is very similar to human sweating. Transpiration includes the use of stomata, which are holes in the plant (especially in the leaves, stem, flowers and roots). Water diffuses out of the stomata as water vapor which allows for efficient flow of liquid water throughout the plant. These stomata also serve as the exits for Carbon Dioxide and Oxygen.
9.2.6
Water moves down the concentration gradient through osmosis from an area with a high to an area with a low concentration. The water that was lost in the process by transpiration is then replaced from vessels and the water goes from an area with high water potential to another area with low water potential. The vessel water column is kept at a balance due to cohesion and adhesion and the charges in the water molecules and xylem attract and repel each other, which defies gravity. Then tension occurs in the columns of water in the xylem because a lot of water is retained in the xylem. The water is then pulled from the root cortex into the xylem cells which is caused by capillary actions. Capillary action is when a liquid rises up a narrow space because of cohesion, adhesion, and intermolecular acttraction between the liquid and the solid which it is rising up.
9.2.7
Gaurd cells are specialized cells that are in charge of opening and closing the stoma. Gaurd cells are very close to the muscles of a human. Gaurd cells are what control the amount of water loss as well as the evaporation of water and gas exchange by closing or opening the Stoma.

Reproduction

9.3.1 Draw and label a diagram showing the structure of a dicotyledonous
animal-pollinated flower.
external image 08flower1.jpg
9.3.2
Pollination is when pollin is carried to a plant by pollinators. There are two types of pollination : Cross pollination and Self pollination. Cross pollination occurs between two different plants, which creates a diversity of plants. Self pollination is within one plant. There is no varation, it is a continuation of a specific species of plants, and it increases harmful mutations. Pollination is of gametophyte generation: haploids. There are also many methods of pollination, such as wind, water, artificial pollination, and pollinators which consists of insects and animals.
Fertilization occurs after the pollen is caught by the stigma. The pollen goes down the pollen tube within the style, into the ovules. The haploid cells of pollen fertilize the ovule haploids, which produces a zygote. Fertilization is of sporophyte generation: diploids.
Seed dispersal is the movement of seeds away from the parent plant. Plants rely on many different dispersal vectors to transport their propagules, which includes abiotic and biotic vectors.
9.3.3
pic1.jpgpic2.jpg


9.3.4
The conditions needed for the germination of a typical seed are warm temperatures and moisture. The warm temperatures allow chemical reactions to occur in plants and start growth. The temperature also need to be optimal because if it is too hot, the plants' proteins will denature, but if it is too cold then the growing progress will be slowed. Moisture softens the testa and allows embryo growth. The moisture is not provided by the cotyledon.


9.3.4 Explain the conditions needed for the germination of a typical seed.

A typical seed will need a large quantity of water to hydrate dry tissue. Before photosynthesis can occur the seed needs to be able to perform aerobic respiration which requires oxygen. Since germination involves enzyme activity in digestion, appropriate temperature is needed for optimum performance of the enzymes

9.3.5 Outline the metabolic processes during germination of a starchy seed.
Living cells in the seed need to be replenished with water, rehydrated. Gibberellin, a plant growth hormone is produced. Starch is digested to maltose faster by producing more amylase. Areas of the seed that involve growth are sent maltose. Maltose is then converted to glucose which is used in cellular respiration, and the synthesis of cellulose.


9.3.6 Explain how flowering is controlled in long-day and short-day plants, including the role of phytochrome.

Phytochrome is a photoreceptor that helps plants detect light by being sensitive to the color red. In long-day plants the flowers bloom when the days get longer. In short-day plants the flowers bloom when the days are relatively shorter.