chapter 8 : Mangrove Swamp

State the unsuitable conditions for habitation in the mangrove swamp. Describe the adaptation of  plants to survive in this environment.

                        Nyatakan keadaan-keadaan persekitaran yang tidak sesuai untuk kehidupan di paya bakau dan kemudian huraikan adaptasi  tumbuhan  untuk hidup dalam keadaan tersebut.

F1: Soft muddy // strong coastal winds pose support problems.

E1 : To  support themselves, mangrove trees such as the Avicennia sp. have long, highly branched underground cable root //the Rhizophora sp. have prop roots/ aerial roots to anchor the plants on to the muddy soil.                                                                                    

F2 : Waterlogged conditions of the soil reduce the amount of oxygen available

E2 : the Avicennia sp. has breathing roots called pneumatophores which grow vertically upwards.

F3 : Direct exposure to the sun/wind leads to a high rate of transpiration

E3: The leaves of the mangrove are covered by a thick layer of cuticle which reduces transpiration during hot days// the leaves are thick and succulent which able to store water.

F4:The high salinity of the sea water makes the surrounding water in the soil hypertonic when compared to the cell sap of the root cells.

E4: The cell sap in the roots cells of the mangrove trees has a higher osmotics pressure than the soil water that surrounds them.This ensures that the roots do not lose water by osmosis// the excess salt in the hypertonic solution of the soil the roots and then then excreted as crystalline salt from the hydathodes

F5: Seeds which fall onto the ground die because they are submerged in the soft and waterlogged soil.

E5: mangrove seeds are able to germinate while still attached to mother plant/viviparity (this phenomenon increases the chances of survival of the mangrove as the seedlings can float horizontally on the water and subsequently get washed up on the sand or mudflats where they settle to establish a new population.

Chapter 8 : Nitrogen Cycle

• All life requires nitrogen-compounds, e.g., proteins and nucleic acids.
• Air, which is 79% nitrogen gas (N₂), is the major reservoir of nitrogen.
• But most organisms cannot use nitrogen in this form.
• Plants must secure their nitrogen in "fixed" form, i.e., incorporated in compounds such as:
  • nitrate ions (NO₃⁻)
  • ammonia (NH₃)
  • urea (NH₂)₂CO
•        most plants can only take up nitrogen in two solid forms: ammonium ion (NH₄⁺ ) and the ion nitrate (NO₃^- ).
• Animals secure their nitrogen (and all other) compounds from plants (or animals that have fed on plants).

Four processes participate in the cycling of nitrogen through the biosphere:

• nitrogen fixation  : - atmospheric fixation by lightning.

                                        - biological fixation by certain microbes — alone or in
                                          a symbiotic  relationship with some plants and animals
                                           Nitrogen-fixing cyanobacteria -
                                         - industrial fixation

• decay  : microorganisms of decay. They break down the molecules in excretions and dead organisms into ammonia.:
• nitrification : most of the ammonia produced by decay is converted into nitrates ;accomplished in two steps:
  • Bacteria of the genus Nitrosomonas oxidize NH₃ to nitrites (NO₂⁻).
  • Bacteria of the genus Nitrobacter oxidize the nitrites to nitrates (NO₃⁻).
  These two groups of autotrophic bacteria are called nitrifying bacteria.
•  denitrification :To complete the cycle other bacteria in the soil carry out a process known as denitrification which converts nitrates back to nitrogen gas. A side product of this reaction is the production of a gas known as nitrous oxide, N2O. Nitrous oxide, also known as "laughing gas" .

Chapter 6: Ruminant Digestive system

Reticulum

The reticulum is a flask-shaped compartment with a "honeycomb" appearance. It moves ingested food (ingesta) into the rumen and the omasum. The reticulum also causes the regurgitation of ingesta during rumination, and acts as a collection compartment for foreign objects.

Rumen

The rumen is a large fermentation chamber (in adult cattle its volume is about 125 litres) which has a very high population of micro-organisms, mainly bacteria, but also protozoa.It is because the bacteria secrete the enzymes necessary for cellulose degradation that ruminants are able to utilize roughage. 

Omasum

The omasum, or "manyplies", contains numerous laminae (tissue leaves) that help grind ingesta. These folds assist in the removal of fluid from the ingesta on their way to the abomasum.

Abomasum

This compartment corresponds to the stomach of the non-ruminant, and is termed the true stomach. It secretes the gastric juices which aid in digestion. The pH of the abomasum is normally in the range of 2,0 to 2,5. This low pH facilitates initial protein breakdown, and kills the bacteria which have spilled over from the rumen.

Ruminants differ from monogastric animals in the following important ways:

• They have no upper canine teeth, or incisors, and have long, thick and rough tongues.
• They ruminate. Chewing the cud helps reduce feed particle size, and mixes saliva into the feed.
• The ruminant digestive system includes a fermentation chamber, called the rumen. The rumen contains micro-organisms which serve some important functions: they make it possible for ruminants to digest fibre (especially those in roughages) and they synthesize nutrients (such as B complex vitamins), and also essential amino acids which become available to the animal when the micro-organisms die, and are digested

LOCOMOTION N SUPPORT : AQUATIC PLANT

Aquatic plants are plants that have adapted to living in aquatic environments
Characteristics of aquatic plants:

• A thin cuticle. Thick cuticles reduce water loss; thus most hydrophytes have no need for thick cuticles.
• Stomata that are open most of the time, because water is abundant and there is no need for it to be retained in the plant. This means that guard cells on the stomata are generally inactive.
• An increased number of stomata, which can be on either side of the leaves.
• A less rigid structure: water pressure supports them.
• Flat leaves on surface plants for flotation.
• Air sacs for flotation.
• Smaller roots: water can diffuse directly into leaves; thus large root systems are not required for water uptake.
• Feathery roots: no need to support the plant.
• Specialized roots able to take in oxygen.All floating plants
  
  • Either have air spaces trapped in their roots, or else air spaces in their bodies (aerenchyma) to help them to float, thus receiving adequate sunshine
  • Have hair on their leaves that traps air
  • Structural adaptations
  • Have hollow stems to float on water.

Paper3:TRANSPIRATION BY POTOMETER

A group of students carry out an experiment to study the effect of environmental factor on the rate of transpiration of a balsam plant. Design a laboratory experiment to determine the effect of the temperature on the rate of transpiration .

http://cd1.edb.hkedcity.net/cd/science/biology/resources/L&t2/practical/Practical-24.pdf

http://en.wikipedia.org/wiki/Potometer

TRANSPORT : Explain the mechanism of blood clotting

Mechanism of blood clotting

Blood Clotting For Minor Wound 

Connective tissue : located in a vessel wall is cut and exposed to the blood.

Platelets : The aggregation of platelets forms a plug. Platelet will stick rapidly.

Platelet Plug

: It can stop the blood loss completely if the damage to  the vessel is small.

Blood Clotting For Severe Wound :

Combination of :

1. Clumped platelets
2. Damaged cells
3. Clotting  factors in the plasma

Form the activator called Thromboplastin

It converts Prothrombin( inactive plasma protein)

With the present of :

1. Calcium ions
2. Vitamin K

To Thrombin(active plasma and act as enzyme)

With the present of :

1. Calcium ions
2. Vitamin K

This thrombin catalyses Fibrinogen(soluble protein) Fibrin (insoluble protein) :

-  mesh over the wound, trapped the red blood cells and sealing the woundto

Problems Related To Blood Clotting

Haemophilia :

1.  An inherited disease cause by a lack of particular Clotting factors in the blood.

2. A person may die due to excessive bleeding from minor cuts and bruises and also can cause spontaneous  internal bleeding.

Thrombosis

1. A process of clot formation inside an unbroken blood vessel

                 2. The clot is called thrombus

                 3.  A blood clot that travels in the bloodstream is called an embolus

                  4. Blood flow in the blood vessel will stop if the embolus

                      lodged in an artery and it can’t pass through it.

TRANSPORT IN PLANTS : TRANSPIRATION

THE MOVEMENT OF WATER FROM THE SOIL TO THE LEAVES
Movement of water through the root

Root hair

*TSA/V is big

*Large surface for *absorption of water by osmosis

*Absorption of ions is achived by active transport

Cells in the cortex layer

*the cellsbecome hypotonic compare to the adjacent cells

*water diffuses through the cytoplasma, vacoule and cell wall of the parenchyma cells until it reaches the endodermis

Endodermis cells

*water diffuses through the cytoplasma andvacoule only

*Casparian Strips lining the side of the cell wall is impermeable to water

Xylem vessel

*The gradient of water concentration resulting an inflow of water into the xylem vessels

*ions is actively transported

*osmotic pressure is increace causing a continous inflow of water –generating Root Pressure

Movement of water through the stem

Xylem vessel

*long, narrow and continuos column generates capillarity

Capillarity / capillary action involving

*the cohesive forces (between water molecules) *adhesive  forces ( water molecules adhere to the xylem wall.)

*forming acontinuos water column within the xylem vessel

*Root Pressure- exerted by the root of a plant

*Transpiration Pull due to the proses of transpiration ocuring at stomata.

Continous upward movement of water in the stem

.