CHEM AND BIO HELP AND TIPS HERE

[Vin]

Can any1 pls xplain me TRANSLOCATION the whole concept, including its source and sink in difrent conditions

Xylem and  phloem carry out long-distance transportation. They are collected together in groups in the vascular bundles.
Translocation is the of the movement of sucrose and amino acids in phloem from regions of production (source) to regions of storage OR to regions of
utilisation in respiration or growth(sinks)  

[someone]

From syllabus:
'describe the advantages and disadvantages of breast-feeding compared with bottle-feeding using formula milk'

i know two advantage of breast milk is that the milk have antibodies and balnced diet, anymore advantage?

are the only disadvantage of breast-feeding are social disadvantage(e.g. its not socially acceptable to breast-feed in public places)?

[Syed Kazim]

Transport of water and minerals

• Root hairs absorb water from the soil by osmosis; mineral ions are actively transported into the root
• Water passes through the root tissue into the xylem by osmosis
• Water travels through the xylem of the root and stem in unbroken columns - the transpiration system
• Water moves through the xylem of the leaf stalk and veins of the leaf
• Water evaporates into the large air spaces within the leaf - the air spaces are saturated with water vapour
• The concentration of water vapour in the atmosphere is lower that that in the air spaces - water vapour diffuses from the leaf through the stomata; the process is called transpiration
• Water lost by cells through evaporation is replaced with water drawn though the cells by osmosis - cells next to the xylem draw water from the xylem by osmosis

Plants lose water through transpiration and gain water through its uptake by the roots. If the loss is greater than the gain then the stomata close and transpiration is reduced. If the loss continues then the cells of the plant lose turgor (rigidity) and the plant wilts.

Different factors increase the rate of transpiration:

• temperature
• wind velocity
• light intensity

Humidity decreases the rate of transpiration.

Transport of food

• The concentration of sugar in the leaf is often lower than the concentration of sugar in the upper ends of the sieve tubes. As a result sugar has to move from the leaf into the sieve tubes by active transport.
• Osmosis draws water from the xylem and increases the pressure in the sieve tubes. As a result sugar solution moves to all parts of the plant through sieve tubes - the process is called translocation - the companion cells support the fuction of sieve cells.
• Pressure in the sieve tubes drops as cells use sugar or store it as starch (e.g. in root cells)

Sugars are used for:

• respiration
• making starch which is a store of food
• making cellulose which is a component of cell walls
• reacting with nitrates to form proteins

[K_M]

4)Outline how enzymes can be manufactured for use in biological washing powders.

Sterilise a fermenter, add nutritive material, introduce bacteria and allow to multiply. Then remove bacteria from fermenter and extract enzymes.

[princess12]

in chemistry for paper 1 from which year i should practice them
urgently reply me

[Raywin]

in chemistry for paper 1 from which year i should practice them
urgently reply me

I would suggest from 2009 onwards to as much as possible.

[K_M]

From syllabus:
'describe the advantages and disadvantages of breast-feeding compared with bottle-feeding using formula milk'

i know two advantage of breast milk is that the milk have antibodies and balnced diet, anymore advantage?

are the only disadvantage of breast-feeding are social disadvantage(e.g. its not socially acceptable to breast-feed in public places)?

Breast feeding:
- develops emotional bond with mother
- contains all types of food except iron in the right proportions (baby is born with iron stored in the liver)
- contains antibodies from the mother which helps the baby to fight infections and possibly develop immunity to any sickness the mother has suffered from
- is at the right temperature
- increases upto 1 litre a day to meet the demands of the baby
- free from bacteria
- readily available

Bottle feeding:
- Contains more sodium, protein and phosphorous and less vitamins
- may not be at the right temperature
- may contain bacteria
- baby can be fed by anyone and not just by the mother
- needs time to be prepared

[Ivo]

Hi, I've got a question.

When plants gain water, can they gain it from active transport.  Say if water potential is greater in root hair cells than in soil, surely water can still move up the concentration gradient.  So is there such thing as active transport of water?

[Syed Kazim]

From syllabus:
'describe the advantages and disadvantages of breast-feeding compared with bottle-feeding using formula milk'

i know two advantage of breast milk is that the milk have antibodies and balnced diet, anymore advantage?

are the only disadvantage of breast-feeding are social disadvantage(e.g. its not socially acceptable to breast-feed in public places)?

Advantages of breastfeeding.

• Breastmilk is made naturally and is therefore free
• Mothers who breastfeed have a much lower chance of developing female cancers

Disadvantages of breastfeeding

• Breastfeeding mothers require to restrict their diet
• Fathers feel left-out of the feeding process

Advantages of Formula Feeding

• Formula is not as easily digested as breast milk, thus allowing the baby to be full for longer and thus the baby needs fewer feeding per day
• Mothers can relax while someone else takes care of the baby
• Bottle feeding is more convenient for mothers who are unconformable breastfeeding in public['li]
  

[Syed Kazim]

Hi, I've got a question.

When plants gain water, can they gain it from active transport.  Say if water potential is greater in root hair cells than in soil, surely water can still move up the concentration gradient.  So is there such thing as active transport of water?

Root hairs absorb water from the soil by osmosis; mineral ions are actively transported into the root

[NidZ- Hero]

and also the second one the answer was given by Raywin: "Source is the place where a particular substance is obtained from. Sink is the final destination of tht substance."

NOV 2006 q5c

its a an example of genetic engineering as the gene that enables de the plants to pump salt out of de root is removed 4rm one species and inserted into another plant its den allowed 2 reproduce n  de genetic engneers make this gene efficient as   b4 de plant gets modified not DAMAGED de salts are pump up it doesnt get accumulated in de plant de get used up  

Outline how enzymes can be manufactured for use in biological washing powders. de answer 4 this is
two types of microorgansiums can be used to manfacture enzymes fungi and bacteria using the fermenter it is a large sterile container with a stirrer and a  pipe to add feedstock (molasses or steep liquor) and air pipes to blow air into de mixture. the microorgansium r added n de liquid is maintained at 26*C and a ph 5-6 de enzymes produced may be extracellular( de extracted by filtering from de feedstock)or intracellular  (filtered 4rm feed stock den crushed and washed wid water. de enzymes r noe in solution

[Raywin]

No, i dont think they can absorb water by active transport. It only implys for minerals which is essential for the plant...  

[Moonlyte]

From syllabus:
'describe the advantages and disadvantages of breast-feeding compared with bottle-feeding using formula milk'

i know two advantage of breast milk is that the milk have antibodies and balnced diet, anymore advantage?

are the only disadvantage of breast-feeding are social disadvantage(e.g. its not socially acceptable to breast-feed in public places)?

advantages of breast milk: right probortion of protein, fat, sugar, vitamis and salts for fetus to grow, contains antibodies, supplied at correct body temp and is free from bacteria.

[thenewkid™]

Hi, I've got a question.

When plants gain water, can they gain it from active transport.  Say if water potential is greater in root hair cells than in soil, surely water can still move up the concentration gradient.  So is there such thing as active transport of water?

nope water always moves by osmosis

are we allowed 2 write anything on the blank pages at the end of the qpaper eg working
 

[Ivo]

nope water always moves by osmosis

are we allowed 2 write anything on the blank pages at the end of the qpaper eg working
 

Of course you are!  But don't write any information that you want scanned and marked.