Wednesday, March 07, 2007

Revision Quiz 7: Chapter 8 - Transport in Mammals

Marks scored: 32/55
hehe... no real BAD comments this time =p since I passed XD hehe... So... here are the answers for last weeks quiz!

1 The heart is made of cardiac muscles. If functions as a pump. It is completely separated into right a left halves by a median septum.

2 The heart needs a constant supply of glucose/food/nutrients and oxygen in order to carry out its pumping action. These are supplied to it via blood vessels known as the coronary arteries. If these arteries are blocked by fatty deposits, oxygen cannot reach the heart muscles. They will degenerate giving rise to coronary heart diseases.

3 The left side of the heart receives oxygenated blood from the lungs and pumps it to the rest of the body via aorta. These blood vessels are highly muscular to withstand the high pressure of blood flow. This is systemic circulation.

4 The right side of the heart receives deoxygenated blood from the rest of the body via vena cava and pumps it to the lungs. These blood vessels contain valves that prevent backflow of blood. This is pulmonary circulation.

5 Oxygen and nutrients first diffuse into the tissue fluid from the blood before entering the body cells. Waste products excrete out of the body cells into this fluid before diffusing into the blood/plasma/capillaries.

6 List FIVE materials transported by the blood.

I wrote: iron, oxygen, carbon dioxide, glucose, platelets

Other possiblities are: amino acids, fatty acids, glycerol, soluble proteins, waste products, hormones, urea, minerals, red blood cells, white blood cells.

Waste products ---> urea, carbon dioxide
Nutrients ---> glucose, amino acids, fatty acids, glycerol
*FOR MARKING: Only main group OR individual material e.g. Waste products and carbon dioxide cannot be placed together in answer.

7 Name
a) the fluid part of the blood; plasma

b) the cells found in the blood; red blood cells + white blood cells

8 Describe the origin of platelets and their function.
- Platelets are fragments of cytoplasm from certain bone marrow cells
- They are required in blood clotting

9 Name the chambers of the heart
- Right atrium
- Right ventricle
- Left atrium
- Left ventricle

10 Name the valves in the heart, stating their site of action and function.

Name Site of action
tricuspid valve Between right atrium & ventricle
bicuspid valve Between left atrium & ventricle
semilunar valves In vena cava, pulmonary ventricle
& aorta

Function of valves: to prevent backflow of blood

Monday, March 05, 2007


When I think Peristalsis, I think Spastic! lol, seriously!

Peristalsis is the involuntary movement in the oesophagus, to help push food down the throat.

So.. it is kinda like a spastic, but... with a good function.

- circular muscle contracts
- longitudinal muscles relaxes
wall -> constricts

         ---> becomes narrower but longer

- longitudinal muscles contracts
- circular muscles relaxes
wall -> dilated

         ---> widens lumen for food to enter

Simple acronym: CCLR (circular contracts, longitudinal relax)

Interesting etymology note:
The word is derived from New Latin and comes from the Greek peristaltikos, peristaltic, from peristellein, "to wrap around," and stellein, "to place."

Sunday, March 04, 2007

5 Steps to Digestion

Here we go. Nothing heavy for today, since it's a relaxation day. So, here's something easy. 5 Steps to Digestion.

- Food starts its journey through the alimentary canal canal by entering the mouth.

That means, once you put the food in your mouth. That's indigestion! Fullstop! Period! End of story!

- Food is broken down by enzymes into simpler substances to be absorbed by the small intestine.

- Food gets diffused by active transport in the small intestines.

- Nutrients of food get used by the body
e.g glucose for energy by respiration in cells

- Any undigested matter that passes through the alimentary canal will be passed out the body by the anus.
NOTE: Do not confuse EGESTION for EXCRETION.
Egestion = removal of anything UNDIGESTED by body e.g roughage/dietary fibre
Excretion = removal of METABOLIC WASTE by body e.g. expelling of carbon dioxide produced by cells during respiration.

Saturday, March 03, 2007

Food Tests: Chapter 5 - Nutrition

Hmm... I'm not sure what I wanted to revise today, so I'll just pick Food Tests!
So it will be rolled out in the following format:

Name of test:
Test for ...?:

~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~

Name of test: Benedict's test
Test for ...?: Reducing sugar
Reagent: Benedict's solution [Copper (II) Sulphate]

1. Solution of 2cm3 Benedict's solution in test tube.
2. Shake mixture and immerse in boiling water.
3. Observe colours:
red precipitate - highest amount of reducing sugar present
orange precipitate
yellow precipitate
green precipitate
blue percipitate - lowest/no amount reducing sugar present

~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~

Name of test: Ethanol emmersion test
Test for ...?: Fats (liquid)
Reagent: ethanol
1. 2cm3 of ethanol in test tube
2. Shake mixture
3. add 2cm3 of distilled water
- Heat felt
- mixture becomes white/milky/cloudy
= fats PRESENT
- No heat felt
- mixture stays translucent
= fats ABSENT

~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~

Name of test: Oil spot test
Test for ...?: Fats (solid)
Reagent: rien (French: nothing)
1. wrap food in filter paper
2. crush by pestle
- If it leaves a translucent spot on filter paper
= fats PRESENT
- If leaves no translucent spot
= fats ABSENT

~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~

Name of test: Biuret test
Test for ...?: Proteins
- sodium hydroxide
- 1% copper (II) sulphate
1. add 1cm3 sodium hydroxide
2. shake THROUGHLY
3. add 1% copper (II) sulphate
Violet = highest amount of proteins
Blue = low/no proteins present

~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~ ~*~

Name of test: Iodine test
Test for ...?: Starch
Reagents: iodine solution (duh.. obviously =p)
1. Drop drops of iodine sol. on food
dark blue = starch present
yellowish-brown = starch absent

Friday, March 02, 2007

Revision Quiz 6: Chapter 7 - Nutrition in Plants

Marks scored: 26/50 (C6)
Wow, and I almost failed =p

1. Photosynthesis is the process by which green plants trap light energy using chlorophyll and convert it to chemical energy for the production of glucose from water and carbon dioxide. Oxygen is released as a by-product.

2. Leaf is an organ specialised for photosynthesis. Its broad and thin lamina provides and large surface area for maximum absorption of light. The thin lamina allows carbon dioxide to enter/diffuse into the cells quickly. The palisade cells contains numerous chloroplast and are packed closely together at the upper surface of the leaf. This enables them to absorb light energy efficiently. The spongy mesophyll cells are loosely packed so that large intercellular spaces are present for rapid diffusion of gaseous exchange. The numerous stomata at the lower epidermis allows rapid gaseous exchange between the leaf and the air. The extensive vain system of xylem and phloem help to provide rapid transport of water to, and manufactured food from the leaf.

Note: Another possible antagonistic action is here. If palisade cells are closely packed, then spongy mesophyll cells must be loosely packed!

3. State the word equation for photosynthesis.

carbon dioxide + water -----------> oxygen + glucose

4. State the effects of varying light intensity on photosynthesis.
- Light energy is trapped by chlorophyll to split water molecules during photosynthesis.
- Increasing light energy will speed up photolysis, hence increasing photosythesis.

5. State the effects of varying wavelights on photosynthesis.
- Red and blue wavelights highly absorbed.
- Green and yellow reflected.
- More light absorbed will increase rate of photosynthesis.

6. State the effects of varying carbon dioxide on photosynthesis.
- Increased CO2, increases rate of glucose produced, resulting in increase in rate of photosynthesis.

7. State the effects of varying temperature on photosynthesis.
- Temp affects rate of enzyme-catalysed reaction in photosynthesis.
- Low temp: enzymes inactive
- High temp: enzymes denature and no photosynthesis takes place.

8. Explain why other forms of life are completely dependant on photosynthesis.
- Can't use light energy directly.
- So depend on photosynthesis for light energy to convert to chem energy for food.
- Photosynthesis produces O2 ---> essential for survival

9. Describe the lack of nitrate ions on plant growth.
- Nitrate ions provide nitrogen for amino acids.
- Sans(French: without) amino acids, plants cannot produce protoplasm or new cells.
- Hence, lack of nitrate ions inhibits plant growth.

10. Describe the lack of magnesium ions on plant growth.
- Magnesium important component in chlorophyll.
- Kein(German: no, neuter negative indefinite article) Magnesium
---> cannot produce chlorophyll
-----> no photosynthesis can be carried on
- leaves turn yellow


Hey ya!/Salut!/Hallo!/Dia dhuit!

Well firstly I have to thank a good friend of mine Colm from Phrasebase (= for inspiring me in creating this blog for my Biology studies for 'O' levels. Go raibh maith agat a Choilm! (okay! enough of my limited Gaeilge. Hopefully I can dabble more on Irish after my O levels among my other languages)

Anyways, here's a link to his blog if you're interested in reading it:

Moving on. By creating this blog I hope to post whatever notes that our biology teacher Ms Evelyn Gay or my classmates have created. Plus I remember stuff better when I type online than when I write. And it's more eligible than my *cough* written notes. lol So.. can't wait to post things here!!

Any corrections, comments or suggestions are all welcomed. Thanks in advance! ... and have I mentioned corrections? Lastly, any and all spams WILL be deleted, if any found.

Warning: Bits of French, German, Malay and occasional swearing may crop up due to being written by a very young and confused polyglot. j/k! lol

See you!