Dear Marists,
Here is the revision schedule in order of priority for Prelim 1.
1. SPA Revision
2. Topical TYS
Units 3.1 A and 3.1 B Reproduction in Plants and Man
Units 3.2 and 3.4 Cell Division & Inheritance
2. Extra TYS Practice
Reproduction in Plants
Reproduction in Man
Genetics & Inheritance
Excretion
3. MSHS Prelim 1 Papers 2010-2012
2013 T1 SOW
Dear Marists,
The SOW for 2013 can be found under the link Revision on the right.
Heres the SOW for Term 1.
The SOW for 2013 can be found under the link Revision on the right.
Heres the SOW for Term 1.
Main Points- Nutrition and Transport in Man
TRANSPORT IN MAN (T6.1, 6.2 ONLY)
-Structure of arteries: thick muscular and elastic walls / no valves
-Structure of veins: thin muscular walls / valves present / movement of blood aided by contraction of skeletal muscles on the veins (blood is pushed along the vein)
-Structure of capillaries: one cell thick endothelium / thin walled (increase rate of exchange) of materials by diffusion
-Cardiac cycle: atrial systole / diastole / ventricular systole / diastole / contraction / relaxation / cardiac muscle / bicuspid valve / tricuspid valve / blood flows / pulmonary artery / aorta / semi lunar valves (aortic and pulmonary valve)
NUTRITION IN MAN
main parts of the digestive system (name and know the functions)
-Digestion take place in 3 places:
a)Mouth: Starch / salivary amylase
b)Stomach: pepsin / protein to polypeptides / HCl / functions of HCl
c)Small intestine: alkaline / villus / pancreas / pancreatic juice(TAL) / intestinal juice(EELMLS) / No digestion in the large intestine
-2 types of amylase: salivary, pancreatic (be specific)
-know products of all the enzyme reactions in the digestive system
eg: starch => maltose
fats => fatty acids + glycerol
proteins => peptones/polypeptides => amino acids
-assimilation IS NOT digestion or absorption!!!
Function of hepatic portal vein (from small intestine to liver for assimilation)
-Absorption: small intestine / villus / adaptations of villus/ lacteals / fatty acids / glycerol
-Assimilation: liver / bile / glycogen / excess glucose / deamination of excess amino acids / urea / urea excreted in urine
-Other functions of liver NOT related to digestive system: breakdown red blood cells / breakdown alcohol
-Structure of arteries: thick muscular and elastic walls / no valves
-Structure of veins: thin muscular walls / valves present / movement of blood aided by contraction of skeletal muscles on the veins (blood is pushed along the vein)
-Structure of capillaries: one cell thick endothelium / thin walled (increase rate of exchange) of materials by diffusion
-Cardiac cycle: atrial systole / diastole / ventricular systole / diastole / contraction / relaxation / cardiac muscle / bicuspid valve / tricuspid valve / blood flows / pulmonary artery / aorta / semi lunar valves (aortic and pulmonary valve)
NUTRITION IN MAN
main parts of the digestive system (name and know the functions)
-Digestion take place in 3 places:
a)Mouth: Starch / salivary amylase
b)Stomach: pepsin / protein to polypeptides / HCl / functions of HCl
c)Small intestine: alkaline / villus / pancreas / pancreatic juice(TAL) / intestinal juice(EELMLS) / No digestion in the large intestine
-2 types of amylase: salivary, pancreatic (be specific)
-know products of all the enzyme reactions in the digestive system
eg: starch => maltose
fats => fatty acids + glycerol
proteins => peptones/polypeptides => amino acids
-assimilation IS NOT digestion or absorption!!!
Function of hepatic portal vein (from small intestine to liver for assimilation)
-Absorption: small intestine / villus / adaptations of villus/ lacteals / fatty acids / glycerol
-Assimilation: liver / bile / glycogen / excess glucose / deamination of excess amino acids / urea / urea excreted in urine
-Other functions of liver NOT related to digestive system: breakdown red blood cells / breakdown alcohol
Nutrition in Man- A Summary
Nutrition in mammals involves:
1. Ingestion of food into body
2. Digestion of food into smaller molecules that can be absorbed into cells
3. Absorption and uptake of nutrients into cells
4. Assimilation: Use of nutrients for energy or making protoplasm
5. Egestion: Removal of undigested and unabsorbed material from the body
This involves the action of the digestive system, which consists of the gut (tube stretching from mouth to anus) and the other glands such as the liver and pancreas.
Gut structure:
1. Outer layer: Serosa (serous coat), secretes oily fluid to reduce friction due to rubbing of the exterior of the organs against each other.
2. Muscle layer: 2 layers of muscle (stomach has 3 layers) arranged in rings (circular muscle), and lengthwise (longitudinal muscle). These contract and relax to bring about peristalsis to push food along the gut.
3. Submucosa (submucous coat): Layer with blood vessels. Blood vessels are required to bring oxygen to gut cells, and to bring digested food to other parts of body. [Sub just means "under", hence the submucosa is just the layer below the mucosa.]
4. Mucosa (Mucous coat): As the name suggests, the layer contains the glands, which produce mucus (for lubrication of food), as well as digestive enzymes and other substances like acid. This is the layer nearest to the lumen of the gut.
Digestion
Can be classified as:
1. Physical: Mechanical breakdown of food into smaller particles, without the use of enzymes. Eg. Mastication in buccal cavity, churning in stomach, emulsification of fats in small intestine.
2. Chemical: Breakdown of food, involving the breaking of chemical bonds, which hence requires the action of enzymes. Eg. Digestion of amylase into maltose by amylase.
Important note: When describing chemical digestion processes, you must include in your answer:
1. Name of enzyme
2. Source of enzyme (where is enzyme made?)
3. Substrate that enzyme acts on
4. Product formed from reaction
Additional Notes
1. All proteases (enzymes that act on proteins/peptones) usually end with "-in" (pepsin, rennin, trypsin, erepsin).
2. Proteases that act on proteins must be produced in the inactive form inside cells, or the protease will cause the destruction of the cell as it will digest the proteins in the cell. Activation of the proteases depends on the type of protease: Those in the stomach are activated by acid, those in the small intestine (trypsin) is activated by another enzyme, enterokinase (from intestinal glands). This ensures protease is only activated in the lumen of the gut.
3. Bile salts allow for PHYSICAL digestion (emulsification) of fats into smaller fat globules, which increases the surface area available for lipase to act on, hence increasing rate of lipase action. Bile salts also allow for the absorption of fatty acids into epithelial cells of villus. They allow the entry of fatty acids and glycerol, after which they then return to the lumen of the small intestine, where the process is repeated again.
4. Bile pigments DO NOT play a digestive function. They are just excretory products, formed from the breakdown of haemoglobin during the destruction of old red blood cells. Of course, since they are pigments, they give faeces their brown colour (but that's not a function!), and are removed out along with the faeces.
5. Digestion of fats: Fats are physically broken into fat globules (emulsification) by action of bile (produced by liver, stored in gall bladder). This increases surface area for lipase (from pancreas and intestinal glands) to digest the lipids into fatty acids and glycerol (chemical digestion).
1. Ingestion of food into body
2. Digestion of food into smaller molecules that can be absorbed into cells
3. Absorption and uptake of nutrients into cells
4. Assimilation: Use of nutrients for energy or making protoplasm
5. Egestion: Removal of undigested and unabsorbed material from the body
This involves the action of the digestive system, which consists of the gut (tube stretching from mouth to anus) and the other glands such as the liver and pancreas.
Gut structure:
1. Outer layer: Serosa (serous coat), secretes oily fluid to reduce friction due to rubbing of the exterior of the organs against each other.
2. Muscle layer: 2 layers of muscle (stomach has 3 layers) arranged in rings (circular muscle), and lengthwise (longitudinal muscle). These contract and relax to bring about peristalsis to push food along the gut.
3. Submucosa (submucous coat): Layer with blood vessels. Blood vessels are required to bring oxygen to gut cells, and to bring digested food to other parts of body. [Sub just means "under", hence the submucosa is just the layer below the mucosa.]
4. Mucosa (Mucous coat): As the name suggests, the layer contains the glands, which produce mucus (for lubrication of food), as well as digestive enzymes and other substances like acid. This is the layer nearest to the lumen of the gut.
Digestion
Can be classified as:
1. Physical: Mechanical breakdown of food into smaller particles, without the use of enzymes. Eg. Mastication in buccal cavity, churning in stomach, emulsification of fats in small intestine.
2. Chemical: Breakdown of food, involving the breaking of chemical bonds, which hence requires the action of enzymes. Eg. Digestion of amylase into maltose by amylase.
Important note: When describing chemical digestion processes, you must include in your answer:
1. Name of enzyme
2. Source of enzyme (where is enzyme made?)
3. Substrate that enzyme acts on
4. Product formed from reaction
Additional Notes
1. All proteases (enzymes that act on proteins/peptones) usually end with "-in" (pepsin, rennin, trypsin, erepsin).
2. Proteases that act on proteins must be produced in the inactive form inside cells, or the protease will cause the destruction of the cell as it will digest the proteins in the cell. Activation of the proteases depends on the type of protease: Those in the stomach are activated by acid, those in the small intestine (trypsin) is activated by another enzyme, enterokinase (from intestinal glands). This ensures protease is only activated in the lumen of the gut.
3. Bile salts allow for PHYSICAL digestion (emulsification) of fats into smaller fat globules, which increases the surface area available for lipase to act on, hence increasing rate of lipase action. Bile salts also allow for the absorption of fatty acids into epithelial cells of villus. They allow the entry of fatty acids and glycerol, after which they then return to the lumen of the small intestine, where the process is repeated again.
4. Bile pigments DO NOT play a digestive function. They are just excretory products, formed from the breakdown of haemoglobin during the destruction of old red blood cells. Of course, since they are pigments, they give faeces their brown colour (but that's not a function!), and are removed out along with the faeces.
5. Digestion of fats: Fats are physically broken into fat globules (emulsification) by action of bile (produced by liver, stored in gall bladder). This increases surface area for lipase (from pancreas and intestinal glands) to digest the lipids into fatty acids and glycerol (chemical digestion).
E-Learning Day 2012
Dear Biology Students,
Please take note the assignments that require completion on ELD.
Please go to the lesson titled '12 ELD Sec 3 Pure Biology' on Ask n Learn and download the 3 files attached.
They are
1: CHD_Lesson
2. CHD_Handout
3. ABO_Blood_Grps_lesson
Spend some time reading and understanding these 2 sub topics.
You may refer to your notes as well as textbook under Topic 5, Transport in Man to further substantiate your learning.
After which, go to 12 ELD Sec3 Pure Biology Quiz and take the Quiz.
You have 30 mins to complete the 12 MCQ Questions.
You may only attempt the Quiz once so please ensure that you have understood the topic before doing the quiz.
Enjoy E learning!
Please take note the assignments that require completion on ELD.
Please go to the lesson titled '12 ELD Sec 3 Pure Biology' on Ask n Learn and download the 3 files attached.
They are
1: CHD_Lesson
2. CHD_Handout
3. ABO_Blood_Grps_lesson
Spend some time reading and understanding these 2 sub topics.
You may refer to your notes as well as textbook under Topic 5, Transport in Man to further substantiate your learning.
After which, go to 12 ELD Sec3 Pure Biology Quiz and take the Quiz.
You have 30 mins to complete the 12 MCQ Questions.
You may only attempt the Quiz once so please ensure that you have understood the topic before doing the quiz.
Enjoy E learning!
Nutrition in Plants- A Summary
What is photosynthesis?
It 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.
Adaptations of the leaf
Leaf is an organ specialized 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.
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.
Effects of varying wavelights on photosynthesis.
Red and blue wavelights highly absorbed.
Green and yellow reflected.
More light absorbed will increase rate of photosynthesis.
Effects of varying carbon dioxide on photosynthesis
Increased CO2, increases rate of glucose produced, resulting in increase in rate of photosynthesis.
Effects of varying temperature on photosynthesis
Temperature affects rate of enzyme-catalysed reaction in photosynthesis.
Low temperature: enzymes inactive
High temperature: enzymes denature and no photosynthesis takes place.
MCQ Questions
1. The word equation which best describes photosynthesis is .
a. carbon dioxide + energy → glucose + oxygen + water
b. glucose + oxygen → water + carbon dioxide + energy
c. glucose + oxygen → water + carbon dioxide + energy
d. water + carbon dioxide + energy → glucose + oxygen
2. Which of the following cells of a leaf do not have chloroplasts?
a. Guard cells
b. Palisade mesophyll
c. Spongy mesophyll
d. Upper epidermis
3. How does most of the carbon dioxide enter the photosynthesising cells of a leaf?
a. Diffusion through the epidermis of the leaf
b. Diffusion through the stomata of the leaf
c. Diffusion through the xylem in the leaf
d. Diffusion through the phloem in the leaf
4. Which of the following statements is the most accurate?
a. Food can travel up the stem in the phloem.
b. Food can travel up or down the stem in the xylem.
c. Food can travel up or down the stem in the phloem.
d. Food can travel down the stem in the phloem.
5. Which of the following conditions is least likely to increase the rate of transpiration in a plant?
a. a rise in temperature.
b. an increase in humidity.
c. increased air movement.
d. increased sunlight
MCQ Answers
1. d
2. d
3. b
4. b
5. b
Structured Question Worked Solutions
1. The equation for photosynthesis is usually given as:
a. Which cell organelle does photosynthesis occur in?
b. Comment on the accuracy of the given equation in describing the process of
photosynthesis.
Solution
a. Chloroplast
b. The equation is not very accurate because it does not show that photosynthesis is a two-step process
only one step is light-dependent and the other is light-independent water is formed during the light-independent stage.
2. Discuss the major adaptations of the leaf to photosynthesis.
Solution
The petiole holds the leaf lamina away from the stem so that the lamina can absorb suffi cient sunlight and air.
The leaf lamina has a large fl at surface compared to its volume.
This enables the leaf to absorb the maximum amount of sunlight for photosynthesis.
A thin expanded lamina ensures that carbon dioxide, the raw material for photosynthesis, can rapidly reach the inner cells of the leaf.
A network of veins extends throughout the leaf. Veins are made of the vascular tissues, xylem and phloem. Xylem transports water and mineral salts to the leaf cells. Phloem transports sugars away from the leaf cells to other parts of the plant. This maintains a concentration gradient so that the photosynthetic reactions proceed in the forward direction.
A waxy cuticle on the leaf epidermis protects the leaf by reducing evaporation of water. Water is an essential raw material for photosynthesis. Lack of water would also make the leaf wilt, reducing surface area for light absorption.
Stomata on the lower epidermis open in sunlight, allowing carbon dioxide to diffuse in and oxygen to diffuse out.
Mesophyll cells of the leaf contain numerous chloroplasts. Chloroplasts contain chlorophyll, which absorbs light energy for photosynthesis.
Mesophyll cells in the upper regions of the leaf (palisade mesophyll) contain more chloroplasts since more light energy can be absorbed near the leaf surface.
An interconnecting system of air spaces in the lower regions of the leaf (spongy mesophyll) allow rapid diffusion of carbon dioxide into mesophyll cells.
3. Discuss why the following statement is true: “Temperature will only increase the rate of photosynthesis to a certain extent. At very high temperatures, the rate of photosynthesis will decrease.”
Solution
Photosynthesis is an enzyme-catalysed reaction.
There will be increased collision of enzyme and substrate as temperature increases.
This results in more enzyme-substrate complex being formed and thus a greater rate of reaction. However, at very high temperatures, enzymes being protein in nature, will be denatured.
The substrate no longer fits into the active site and an enzyme-substrate complex cannot be formed.
Thus the rate of photosynthesis will decrease.
It 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.
Adaptations of the leaf
Leaf is an organ specialized 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.
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.
Effects of varying wavelights on photosynthesis.
Red and blue wavelights highly absorbed.
Green and yellow reflected.
More light absorbed will increase rate of photosynthesis.
Effects of varying carbon dioxide on photosynthesis
Increased CO2, increases rate of glucose produced, resulting in increase in rate of photosynthesis.
Effects of varying temperature on photosynthesis
Temperature affects rate of enzyme-catalysed reaction in photosynthesis.
Low temperature: enzymes inactive
High temperature: enzymes denature and no photosynthesis takes place.
MCQ Questions
1. The word equation which best describes photosynthesis is .
a. carbon dioxide + energy → glucose + oxygen + water
b. glucose + oxygen → water + carbon dioxide + energy
c. glucose + oxygen → water + carbon dioxide + energy
d. water + carbon dioxide + energy → glucose + oxygen
2. Which of the following cells of a leaf do not have chloroplasts?
a. Guard cells
b. Palisade mesophyll
c. Spongy mesophyll
d. Upper epidermis
3. How does most of the carbon dioxide enter the photosynthesising cells of a leaf?
a. Diffusion through the epidermis of the leaf
b. Diffusion through the stomata of the leaf
c. Diffusion through the xylem in the leaf
d. Diffusion through the phloem in the leaf
4. Which of the following statements is the most accurate?
a. Food can travel up the stem in the phloem.
b. Food can travel up or down the stem in the xylem.
c. Food can travel up or down the stem in the phloem.
d. Food can travel down the stem in the phloem.
5. Which of the following conditions is least likely to increase the rate of transpiration in a plant?
a. a rise in temperature.
b. an increase in humidity.
c. increased air movement.
d. increased sunlight
MCQ Answers
1. d
2. d
3. b
4. b
5. b
Structured Question Worked Solutions
1. The equation for photosynthesis is usually given as:
a. Which cell organelle does photosynthesis occur in?
b. Comment on the accuracy of the given equation in describing the process of
photosynthesis.
Solution
a. Chloroplast
b. The equation is not very accurate because it does not show that photosynthesis is a two-step process
only one step is light-dependent and the other is light-independent water is formed during the light-independent stage.
2. Discuss the major adaptations of the leaf to photosynthesis.
Solution
The petiole holds the leaf lamina away from the stem so that the lamina can absorb suffi cient sunlight and air.
The leaf lamina has a large fl at surface compared to its volume.
This enables the leaf to absorb the maximum amount of sunlight for photosynthesis.
A thin expanded lamina ensures that carbon dioxide, the raw material for photosynthesis, can rapidly reach the inner cells of the leaf.
A network of veins extends throughout the leaf. Veins are made of the vascular tissues, xylem and phloem. Xylem transports water and mineral salts to the leaf cells. Phloem transports sugars away from the leaf cells to other parts of the plant. This maintains a concentration gradient so that the photosynthetic reactions proceed in the forward direction.
A waxy cuticle on the leaf epidermis protects the leaf by reducing evaporation of water. Water is an essential raw material for photosynthesis. Lack of water would also make the leaf wilt, reducing surface area for light absorption.
Stomata on the lower epidermis open in sunlight, allowing carbon dioxide to diffuse in and oxygen to diffuse out.
Mesophyll cells of the leaf contain numerous chloroplasts. Chloroplasts contain chlorophyll, which absorbs light energy for photosynthesis.
Mesophyll cells in the upper regions of the leaf (palisade mesophyll) contain more chloroplasts since more light energy can be absorbed near the leaf surface.
An interconnecting system of air spaces in the lower regions of the leaf (spongy mesophyll) allow rapid diffusion of carbon dioxide into mesophyll cells.
3. Discuss why the following statement is true: “Temperature will only increase the rate of photosynthesis to a certain extent. At very high temperatures, the rate of photosynthesis will decrease.”
Solution
Photosynthesis is an enzyme-catalysed reaction.
There will be increased collision of enzyme and substrate as temperature increases.
This results in more enzyme-substrate complex being formed and thus a greater rate of reaction. However, at very high temperatures, enzymes being protein in nature, will be denatured.
The substrate no longer fits into the active site and an enzyme-substrate complex cannot be formed.
Thus the rate of photosynthesis will decrease.
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