UNIT 2: ANIMAL AND PLANT PHYSIOLOGY
NUTRITION IN FLOWERING PLANTS
sunlight
Carbon dioxide + water ------------> Glucose (food for plant) + oxygen(by-product)
Chlorophyll
CO2 + H2O ------------> C6H12O6 + O2
**Chlorophyll absorbs the light energy needed for the reaction to take place. Photosynthesis converts light energy into chemical energy.
Test to show the production of starch during photosynthesis
Test for the requirement for light
1. Take a plant to a dark place for a few days, so its leave does not contain starch. (destarched plant)
2. Bring the plant out into the light and mask one of the leaves with a light-proof card. Leave it there for a few hours.
3. Dip the leave in a hot water bath. This kills the leave.
4. Dip into boiling alcohol (there should be no naked flame), it removes the chlorophyll.
5. Dip into boiling water again to soften the leaf.
6. Cover leaf with iodine solution. If it turns blue-black, starch is present.
Results: The part where the black paper had covered has turned orange because no sunlight reached that part to photosynthesize. The blue-black part shows
that there is starch present.
Test for the requirement for chlorophyll
1. Use a plant with variegated leaves and take it into a dark place for two days so no starch contained. (destarched plant)
➢ On parts where it is not green (without chlorophyll present), and on parts where it is green (with chlorophyll)
2. Put into sunlight
3. Repeat steps 3-6 (from above) → iodine test for starch
Test for the requirement for carbon dioxide
1. Put a plant in a dark place for 2 days, so the leaves do not contain starch. (destarched plant)
2. Put the destarched plant into the light and enclose one leaf on the destarched plant in a tube or transparent bag containing potassium hydroxide.
➢ This absorbs carbon dioxide so there is no carbon dioxide in the air around the leaf.
3. Repeat steps 3-6 (from above) → iodine test for starch
** no starch present on the leaf that was in the container, starch present on the leaves that were in the air.
Structure of the leaf – how it adapts to photosynthesis
waxy cuticle – to reduce water loss by evaporation
upper epidermis – one cell thick, transparent, to allow easy light penetration
palisade mesophyll – tightly packed together, full of chloroplasts and close to the
source of light. This is the main site of photosynthesis.
Spongey mesophyll – lots of air spaces to aid diffusion of gases
Lower epidermis – contains pores(stomata) for gas exchange. Stomata are on under
side to reduce excess water loss.
Thin – aids light penetration
Large surface area – absorbs lot of light energy
Veins – contains xylem vessels which carry water to the leaf and phloem vessels
which carry products of photosynthesis (glucose) away.
- Guard cells → control opening and closing of the stomata pores
- Xylem vessel → conducts water
- Phloem vessel → conducts food
,Light intensity and the rate of photosynthesis
1. Position bench lamp a measured distance from the beaker containing pondweeds
2. Allow two minutes for the pondweed to adjust to the light intensity
3. Count the number of bubbles released over a one-minute period
4. Repeat for a second one-minute period
5. Move the lamp 20 cm further and repeat steps 2-4
6. Continue at further intervals
// experiment might not be valid: background light, temperature, size of bubbles
** to be improved → measure the volume of oxygen produced
Factors affecting the rate of photosynthesis
• When the light intensity rises, the rate rises too.
• If the plant is put in a closed container with higher than normal
concentration of carbon dioxide, it will phtosynthesise at a
faster rate.
• If there is a high light intensity and high carbon dioxide
concentration, it will photosynthesise faster as well.
• High temperatures will increase the rate too.
The plant’s uses for glucose
Glucose is a single sugar (monosaccharide). Plant cells can convert it
into other sugars such as another monosaccharide called fructose and
the disaccharide sucrose. It can also be changed into another polymer,
the polysaccharide called cellulose, which forms plant cell walls.
- All these compounds are carbohydrates. Plant cells can also convert glucose into lipids.
- Lipids are needed for the membrane of all cells and are also an energy store in many seeds and fruits such as peanuts, sunflower seeds.
- Carbohydrates and lipids both contain only three elements – carbon, hydrogen and oxygen – and so they can be inter-converted without the need for a
supply of other elements.
- Proteins contain these elements too, but all amino acids also contain nitrogen.
- This is obtained as nitrate ions from the soil, through the plant’s roots. Other compounds in plants contain other elements. For example, chlorophyll
contains magnesium ions, which are also absorbed from water in the soil.
Glucose (for respiration)
• sucrose for transport
• starch for storage
• cellulose for cell walls
• proteins and DNA (needs nitrate) – obtained from mineral ions in soil
• lipids – obtained from oil in seeds
• chlorophyll – obtained from magnesium ions in soil
Mineral nutrition
Plants take up minerals from the soil water by active transport. Without certain minerals, plants suffer deficiency symptoms.
MINERAL USES DEFICIENCY SYMPTOMS
NITRATES Makes amino acids, proteins and DNA Stunted growth, older leaves turn yellow
MAGNESIUM Part of chlorophyll molecule Leaves turn yellow
Water culture experiment
This experiment should be set for a couple of variables.
Firstly, each set should use the cutting from the same plant so that the experiment could be
valid.
Culture solution should be put into the flask.
One set should contain all needed minerals and the others should lack at least one mineral
such as magnesium.
The plant roots should be placed inside the solution with its leaves outside the flask.
Then, place an air tube down the flask so that oxygen can be pumped in for respiration of
the plant.
Once the minerals and oxygen reached the plant’s roots, it will undergo active transport.
Aluminium foil should be wrapped outside the flask to prevent algae growth.
If algae grow inside the flask, it will compete with the controlled plant for minerals, making
the experiment invalid.
2
, NUTRITION IN HUMANS
A balanced diet
A balanced diet should contain appropriate proportions of carbohydrate, protein, lipid, vitamins, minerals, water and dietary fibre.
Food component Sources Function
Carbohydrate Monosaccharide- - Provides us energy and for growth and repair
Glucose: fruits and honey
Fructose: fruits and honey
Galactose: milk and dairy products - Polysaccharides:
Disaccharide- Starch: as major storage of carbohydrate in plants
Sucrose: sugar cane Glycogen: as major storage of carbohydrates in animals
Maltose: germinating barley Cellulose: as main component in plant cell walls.
Lactose: milk and dairy products
Polysaccharides-
Starch: rice, bread, pasta
Glycogen: meat
Cellulose: vegetables
Protein • Non-essential amino acids → can be - For growth and repair.
produced by human body - Synthesis of enzymes, antibodies and some hormones.
• Essential amino acids → have to be obtained - Amino acids can convert into carbohydrates in the liver for energy supply
from the diet: eggs, seeds and nuts
Lipid Triglycerides: 3 fatty acids + 1 glycerol - Stored in adipose tissues under the skin, as subcutaneous fat, or around
the internal organs for energy reserve, insulator and shock absorber to
Fat cuts of beef, pork and lamb. Butter oil and protect the internal organs.
milk.
- For transport and storage of lipid-soluble vitamins in the body.
- Involved in making some hormones.
Vitamin A Carrots, liver Formation of pigment in the retina for night vision
Vitamin C Orange, strawberry, kiwi Growth and repair of tissues
Vitamin D Milk, dairy products (can be produced by the skin - Promoting the absorption of calcium and phosphate ions
under sunlight)
Mineral calcium Milk and dairy products • Formation of bones and teeth
• Blood clotting
• Muscle contraction
Mineral iron Chicken, fish and liver - Component of haemoglobin in red blood cells for carrying oxygen
Fibre Oats, carrots, potato - Adds bulk to food to stimulate peristalsis
- Holds a lot of water to allow faeces to remain soft
Water Cucumbers, tomato, spinach, plain water Solvent: dissolves chemicals in the body
Medium: for chemical reactions to take place
Transport medium: blood
Cooling agent: regulate body temperature
Reactant: in metabolic reactions
Energy requirements
Even when we are asleep, we need energy for maintaining out body temperature and to keep our heart beating, and to keep impulses travelling in our nervous
system.
The total amount of energy you need depends on the physical work that you do, your age, your gender and your body size.
Men use more energy than women because they have a greater proportion of muscle to body fat. Muscle cells are more active and use energy faster than fat
cells. Generally, the larger body mass, the greater the need for energy.
Pregnant women need more energy because of the extra weight they have to carry. During pregnancy, a woman also needs extra iron and calcium for the
growth of the foetus.
Practical test for energy content of a food sample.
1. Place 20cm3 of water in a boiling tube. Use a thermometer to measure the temperature at the start
2. Weigh a small portion of the food sample to be tested.
3. Hold the burning portion of the food sample under the bottom of the tube so that the flame touches the tube
4. Note the increase in temperature of the water in the tube
3
, 5. Calculate energy content in the food.
Heat energy released per grams:
(4.2 x 20 x temp rise)
in Jg-1
mass burned
4.2 = joules of energy to raise 1cm3 of water by 1°C
20 = volume of water
Inaccuracy due to:
- Energy loss in atmosphere, boiling tube and tongs
- not all of food sample burned
- difficult to collect all bits left after burning
- difficult to hold each food sample at same distance below tube
→ A more reliable way would be to use a food calorimeter
It burns in pure oxygen – burning efficient, all food burnt
Heat is transferred to coil which heats water. Water is stirred – ensures
even heat distribution
The calorimeter is airtight and insulated – no draft, no heat lost to the environment, less heat lost overall.
The digestive system
The three main classes of food are broken down by three classes of enzymes. Carbohydrates are digested by enzymes
called carbohydrases. Proteins are acted upon by proteases, and enzymes called lipases break down lipids. Digestion
begins in the mouth.
1. Ingestion – taking food into the body through the mouth
2. Digestion – the chemical and mechanical breakdown of food. It converts large insoluble molecules into small soluble molecules, which can be
absorbed into the blood.
3. Absorption – the soluble products of digestion pass
across the wall of the small intestine into the blood
stream and lymphatic system.
4. Assimilation – the soluble food products are absorbed Mouth Salivary gland
from the blood into the cells and used to build up new
parts of cells.
5. Egestion – removal of faeces by the body. This is waste
Oesophagus
which has passed through the gut without entering the
Tongue
cells.
Trachea
1. Mouth
Mechanical digestion by teeth. Food is broken down into
smaller pieces providing a larger surface area for action of
enzymes. Liver Stomach
Saliva contains water, mucus to lubricate the food, and
amylase to start the digestion of starch into smaller
carbohydrates such as disaccharide maltose. Gall bladder
Pancreas
2. Oesophagus
Food is pushed down the oesophagus by contracting muscles. Duodenum
Small colon
This is called peristalsis. Alternately, circular muscles contract intestine Ileum
then longitudinal muscles contract.
rectum
3. The stomach Large
Hydrochloric acid kills bacteria; the protease enzyme pepsin intestine
Appendix
breaks down proteins into peptides.
The muscles in the wall of the stomach contract the contents to
mix together.
Anus
4. Pancreas
The pancreas produces amylase and a protease enzyme called
trypsin and lipase. The enzymes, altogether called pancreatic juice, travel down a duct into the small intestine.
5. Liver
The liver produces bile which is stored in the gall bladder. It travels down the bile duct into the small intestine.
6. Digestion in the small intestine
Bile is alkaline so it neutralizes the acidic food from the stomach. Bile also emulsifies fats (physically breaks them into smaller droplets). Enzymes from the
pancreas and the wall of the small intestine finish the digestion of proteins, carbohydrates and fats.
4
NUTRITION IN FLOWERING PLANTS
sunlight
Carbon dioxide + water ------------> Glucose (food for plant) + oxygen(by-product)
Chlorophyll
CO2 + H2O ------------> C6H12O6 + O2
**Chlorophyll absorbs the light energy needed for the reaction to take place. Photosynthesis converts light energy into chemical energy.
Test to show the production of starch during photosynthesis
Test for the requirement for light
1. Take a plant to a dark place for a few days, so its leave does not contain starch. (destarched plant)
2. Bring the plant out into the light and mask one of the leaves with a light-proof card. Leave it there for a few hours.
3. Dip the leave in a hot water bath. This kills the leave.
4. Dip into boiling alcohol (there should be no naked flame), it removes the chlorophyll.
5. Dip into boiling water again to soften the leaf.
6. Cover leaf with iodine solution. If it turns blue-black, starch is present.
Results: The part where the black paper had covered has turned orange because no sunlight reached that part to photosynthesize. The blue-black part shows
that there is starch present.
Test for the requirement for chlorophyll
1. Use a plant with variegated leaves and take it into a dark place for two days so no starch contained. (destarched plant)
➢ On parts where it is not green (without chlorophyll present), and on parts where it is green (with chlorophyll)
2. Put into sunlight
3. Repeat steps 3-6 (from above) → iodine test for starch
Test for the requirement for carbon dioxide
1. Put a plant in a dark place for 2 days, so the leaves do not contain starch. (destarched plant)
2. Put the destarched plant into the light and enclose one leaf on the destarched plant in a tube or transparent bag containing potassium hydroxide.
➢ This absorbs carbon dioxide so there is no carbon dioxide in the air around the leaf.
3. Repeat steps 3-6 (from above) → iodine test for starch
** no starch present on the leaf that was in the container, starch present on the leaves that were in the air.
Structure of the leaf – how it adapts to photosynthesis
waxy cuticle – to reduce water loss by evaporation
upper epidermis – one cell thick, transparent, to allow easy light penetration
palisade mesophyll – tightly packed together, full of chloroplasts and close to the
source of light. This is the main site of photosynthesis.
Spongey mesophyll – lots of air spaces to aid diffusion of gases
Lower epidermis – contains pores(stomata) for gas exchange. Stomata are on under
side to reduce excess water loss.
Thin – aids light penetration
Large surface area – absorbs lot of light energy
Veins – contains xylem vessels which carry water to the leaf and phloem vessels
which carry products of photosynthesis (glucose) away.
- Guard cells → control opening and closing of the stomata pores
- Xylem vessel → conducts water
- Phloem vessel → conducts food
,Light intensity and the rate of photosynthesis
1. Position bench lamp a measured distance from the beaker containing pondweeds
2. Allow two minutes for the pondweed to adjust to the light intensity
3. Count the number of bubbles released over a one-minute period
4. Repeat for a second one-minute period
5. Move the lamp 20 cm further and repeat steps 2-4
6. Continue at further intervals
// experiment might not be valid: background light, temperature, size of bubbles
** to be improved → measure the volume of oxygen produced
Factors affecting the rate of photosynthesis
• When the light intensity rises, the rate rises too.
• If the plant is put in a closed container with higher than normal
concentration of carbon dioxide, it will phtosynthesise at a
faster rate.
• If there is a high light intensity and high carbon dioxide
concentration, it will photosynthesise faster as well.
• High temperatures will increase the rate too.
The plant’s uses for glucose
Glucose is a single sugar (monosaccharide). Plant cells can convert it
into other sugars such as another monosaccharide called fructose and
the disaccharide sucrose. It can also be changed into another polymer,
the polysaccharide called cellulose, which forms plant cell walls.
- All these compounds are carbohydrates. Plant cells can also convert glucose into lipids.
- Lipids are needed for the membrane of all cells and are also an energy store in many seeds and fruits such as peanuts, sunflower seeds.
- Carbohydrates and lipids both contain only three elements – carbon, hydrogen and oxygen – and so they can be inter-converted without the need for a
supply of other elements.
- Proteins contain these elements too, but all amino acids also contain nitrogen.
- This is obtained as nitrate ions from the soil, through the plant’s roots. Other compounds in plants contain other elements. For example, chlorophyll
contains magnesium ions, which are also absorbed from water in the soil.
Glucose (for respiration)
• sucrose for transport
• starch for storage
• cellulose for cell walls
• proteins and DNA (needs nitrate) – obtained from mineral ions in soil
• lipids – obtained from oil in seeds
• chlorophyll – obtained from magnesium ions in soil
Mineral nutrition
Plants take up minerals from the soil water by active transport. Without certain minerals, plants suffer deficiency symptoms.
MINERAL USES DEFICIENCY SYMPTOMS
NITRATES Makes amino acids, proteins and DNA Stunted growth, older leaves turn yellow
MAGNESIUM Part of chlorophyll molecule Leaves turn yellow
Water culture experiment
This experiment should be set for a couple of variables.
Firstly, each set should use the cutting from the same plant so that the experiment could be
valid.
Culture solution should be put into the flask.
One set should contain all needed minerals and the others should lack at least one mineral
such as magnesium.
The plant roots should be placed inside the solution with its leaves outside the flask.
Then, place an air tube down the flask so that oxygen can be pumped in for respiration of
the plant.
Once the minerals and oxygen reached the plant’s roots, it will undergo active transport.
Aluminium foil should be wrapped outside the flask to prevent algae growth.
If algae grow inside the flask, it will compete with the controlled plant for minerals, making
the experiment invalid.
2
, NUTRITION IN HUMANS
A balanced diet
A balanced diet should contain appropriate proportions of carbohydrate, protein, lipid, vitamins, minerals, water and dietary fibre.
Food component Sources Function
Carbohydrate Monosaccharide- - Provides us energy and for growth and repair
Glucose: fruits and honey
Fructose: fruits and honey
Galactose: milk and dairy products - Polysaccharides:
Disaccharide- Starch: as major storage of carbohydrate in plants
Sucrose: sugar cane Glycogen: as major storage of carbohydrates in animals
Maltose: germinating barley Cellulose: as main component in plant cell walls.
Lactose: milk and dairy products
Polysaccharides-
Starch: rice, bread, pasta
Glycogen: meat
Cellulose: vegetables
Protein • Non-essential amino acids → can be - For growth and repair.
produced by human body - Synthesis of enzymes, antibodies and some hormones.
• Essential amino acids → have to be obtained - Amino acids can convert into carbohydrates in the liver for energy supply
from the diet: eggs, seeds and nuts
Lipid Triglycerides: 3 fatty acids + 1 glycerol - Stored in adipose tissues under the skin, as subcutaneous fat, or around
the internal organs for energy reserve, insulator and shock absorber to
Fat cuts of beef, pork and lamb. Butter oil and protect the internal organs.
milk.
- For transport and storage of lipid-soluble vitamins in the body.
- Involved in making some hormones.
Vitamin A Carrots, liver Formation of pigment in the retina for night vision
Vitamin C Orange, strawberry, kiwi Growth and repair of tissues
Vitamin D Milk, dairy products (can be produced by the skin - Promoting the absorption of calcium and phosphate ions
under sunlight)
Mineral calcium Milk and dairy products • Formation of bones and teeth
• Blood clotting
• Muscle contraction
Mineral iron Chicken, fish and liver - Component of haemoglobin in red blood cells for carrying oxygen
Fibre Oats, carrots, potato - Adds bulk to food to stimulate peristalsis
- Holds a lot of water to allow faeces to remain soft
Water Cucumbers, tomato, spinach, plain water Solvent: dissolves chemicals in the body
Medium: for chemical reactions to take place
Transport medium: blood
Cooling agent: regulate body temperature
Reactant: in metabolic reactions
Energy requirements
Even when we are asleep, we need energy for maintaining out body temperature and to keep our heart beating, and to keep impulses travelling in our nervous
system.
The total amount of energy you need depends on the physical work that you do, your age, your gender and your body size.
Men use more energy than women because they have a greater proportion of muscle to body fat. Muscle cells are more active and use energy faster than fat
cells. Generally, the larger body mass, the greater the need for energy.
Pregnant women need more energy because of the extra weight they have to carry. During pregnancy, a woman also needs extra iron and calcium for the
growth of the foetus.
Practical test for energy content of a food sample.
1. Place 20cm3 of water in a boiling tube. Use a thermometer to measure the temperature at the start
2. Weigh a small portion of the food sample to be tested.
3. Hold the burning portion of the food sample under the bottom of the tube so that the flame touches the tube
4. Note the increase in temperature of the water in the tube
3
, 5. Calculate energy content in the food.
Heat energy released per grams:
(4.2 x 20 x temp rise)
in Jg-1
mass burned
4.2 = joules of energy to raise 1cm3 of water by 1°C
20 = volume of water
Inaccuracy due to:
- Energy loss in atmosphere, boiling tube and tongs
- not all of food sample burned
- difficult to collect all bits left after burning
- difficult to hold each food sample at same distance below tube
→ A more reliable way would be to use a food calorimeter
It burns in pure oxygen – burning efficient, all food burnt
Heat is transferred to coil which heats water. Water is stirred – ensures
even heat distribution
The calorimeter is airtight and insulated – no draft, no heat lost to the environment, less heat lost overall.
The digestive system
The three main classes of food are broken down by three classes of enzymes. Carbohydrates are digested by enzymes
called carbohydrases. Proteins are acted upon by proteases, and enzymes called lipases break down lipids. Digestion
begins in the mouth.
1. Ingestion – taking food into the body through the mouth
2. Digestion – the chemical and mechanical breakdown of food. It converts large insoluble molecules into small soluble molecules, which can be
absorbed into the blood.
3. Absorption – the soluble products of digestion pass
across the wall of the small intestine into the blood
stream and lymphatic system.
4. Assimilation – the soluble food products are absorbed Mouth Salivary gland
from the blood into the cells and used to build up new
parts of cells.
5. Egestion – removal of faeces by the body. This is waste
Oesophagus
which has passed through the gut without entering the
Tongue
cells.
Trachea
1. Mouth
Mechanical digestion by teeth. Food is broken down into
smaller pieces providing a larger surface area for action of
enzymes. Liver Stomach
Saliva contains water, mucus to lubricate the food, and
amylase to start the digestion of starch into smaller
carbohydrates such as disaccharide maltose. Gall bladder
Pancreas
2. Oesophagus
Food is pushed down the oesophagus by contracting muscles. Duodenum
Small colon
This is called peristalsis. Alternately, circular muscles contract intestine Ileum
then longitudinal muscles contract.
rectum
3. The stomach Large
Hydrochloric acid kills bacteria; the protease enzyme pepsin intestine
Appendix
breaks down proteins into peptides.
The muscles in the wall of the stomach contract the contents to
mix together.
Anus
4. Pancreas
The pancreas produces amylase and a protease enzyme called
trypsin and lipase. The enzymes, altogether called pancreatic juice, travel down a duct into the small intestine.
5. Liver
The liver produces bile which is stored in the gall bladder. It travels down the bile duct into the small intestine.
6. Digestion in the small intestine
Bile is alkaline so it neutralizes the acidic food from the stomach. Bile also emulsifies fats (physically breaks them into smaller droplets). Enzymes from the
pancreas and the wall of the small intestine finish the digestion of proteins, carbohydrates and fats.
4
