Nutrition Flashcards
Differentiate among heterotrophic, autotrophic and saprophytic nutrition
Autrotrophs are organisms that prepare their own food through the process of photosynthesis
Heterotrophs are organisms that can’t prepare their own food and depend on autotrophs for nutrition
Innsaoriphytuc nutrition, the organisms obtain their food from dead and decaying organic matter of dead plants, dead animals and other decomposing matter
Equation for photosynthesis in green plants
6CO2 + 6H2O ——-> C6H12O6 + 6O2
Describe the light-dependent stage (light stage)
The light energy is absorbed by the chlorophyll in chloroplasts and is used to split water into hydrogen and oxygen. Oxygen is released as a gas.
Describe the light-independent stage (dark stage)
The hydrogen combines with carbon dioxide to make glucose. This stage doesn’t need light
Conditions required for photosynthesis
Carbon dioxide
Water
Sunlight energy
Chlorophyll
A suitable temp
Enzymes
Adaptation of the leaf for photosynthesis
The lamina is usually broad and flat with a large surface area to absorb a lot of light and carbon dioxide
The lamina is thin to allow light and CO2 to reach all cells
The lamina is held out flat by the veins to catch as much light as possible
Fate of glucose
Can be used by leaf cells in respiration to produce energy
Can be condensed to starch and stored
Can be converted to sucrose and transported
Environmental factors that affect the rate of photosynthesis
Light limits the rate between dusk and dawn
Temperature limits the rate in cool seasons in temperate region
CO2
water
Function of nitrogen in plant nutrition
Necessary for the formation of proteins
Function of magnesium in plant nutrition
Necessary in the formation of chlorophyll
Effect of the lack of nitrogen on seedlings
Small yellow leaves and poor growth
Lack of magnesium on seedlings
Leaves yellow between the veins
What test is used for reducing sugars?
Benedict’s test
Describe the test for starch
A few drops of iodine solution is added
Positive result: Blue-black results
Describe the test for protein
An equal volume of protein solution and potassium hydroxide is put into a test tube. The mixture is stirred and 2cm^3 of copper sulfate solution is added
Positive results: solution turns purple
Name the test for protein
Biuret test
Describe the test for lipids
Place the given amount of ethanol in a test tube. Add one drop of test substance and shake. Add an equal volume of water.
Positive results: milky-white emulsion forms
Describe the test for reducing sugars
Add an equal volume of Benedict’s solution and shake. Heat the mixture.
Positive results: orange-red precipitate
Chemical and physical properties of monosaccharides
Soluble
Small molecules
Sweet taste
Chemical and physical properties of disaccharide
Soluble
Sweet taste
Chemical and physical properties of polysaccharide
Insoluble
Don’t have a sweet taste
Chemical and physical properties of protein
Some soluble (haemoglobin)
Some insoluble (keratin)
Chemical and physical properties of lipids
Insoluble in water
Importance of vitamin a-k
A- aids vision in dim light
B- assists in respiration
C- keeps tissues healthy
D- aids absorption of calcium
K- aids in blood clotting
Deficiency of vitamins A, B1, B6, C, D
A- night blindness
B1- beriberi
B6- depression
C- scurvy
D- rickets
State the necessity for hydrolysis and neutralisation in testing for non-reducing sugars
hydrolysis is necessary to break down complex carbohydrates into their simpler monosaccharide units, while neutralization is essential to create a neutral pH environment suitable for subsequent testing for non-reducing sugars.
How are mammals different from other animals
They have more than one type of tooth
Function of the incisor
Cutting and biting food
Function of the canine
Grasping and tearing food
Function of the premolar
Crush and grind food
Function of the molar
Crush and grind food
How many teeth do adults have?
32
Use of fluoride to the teeth
Helps to prevent tooth decay
Importance of mechanical digestion
It makes food easier to swallow
It gives the pieces of food a larger surface area for digestive enzymes to act on
Function of the enamel
Covers the crown
Hardest substance
Resistant to chipping and decay
Protects the tooth
Function of the dentine
Forms the bulk of the tooth
Provides support to the enamel
Protects the innermost pulp chamber
Function of the pulp chamber
Provides the sensation of pain or discomfort when the tooth is damaged
Function of the gall bladder
Stored bile
Process of digestion
1) mouth
2) oesophagus
3) stomach
4) duodenum
5) ileum
6) colon
7) rectum
Why is it impossible to swallow and inhale at the same time?
The epiglottis covers the trachea as you swallow to prevent food from going in the trachea
What is chyme
A mixture of enzymes, mucus and HCL
Gastric juice consists of:
Mucus
HCL
pepsin
Where does the digestion of protein begin
In the stomach
Explain the role and importance of enzymes
They are biological catalysts
Enzymes speed up chemical reactions occurring in living cells. During digestion, enzymes speed up the rate at which the large insoluble food molecules are broken down into small, soluble molecules
Properties of enzymes
They are all proteins
They’re required in small amounts
They’re prevented from working by poisons like cyanide
Each enzyme is specific for the type of chemical reaction it speeds up
They work best at optimum temperature
They’re denatured by high temperatures
Role of digestive enzymes in the mouth
Begins to digest the starch in the food
“Salivary amylase”
It breaks down complex carbohydrates, such as starch, into smaller polysaccharides and disaccharides.
Role of the digestive enzymes in stomach
Pepsin then plays a crucial role in the digestion of proteins, breaking them down into smaller peptides.
Role of the pancreatic enzymes in the small intestine
Pancreatic amylase: starch —-> maltose
Trypsin: continues to digest- protein —-> peptides
Pancreatic lipase: lipids —–> glycerol
Role of villi in absorption of products of digestion
The numerous villi present in the small intestine significantly increase the surface area available for absorption of nutrients
Define assimilation
The process of incorporating and making use of the digested food into the body
What happens to monosaccharides in assimilation?
They’re taken to the liver, then to the rest of the body where:
1) it’s used for respiration
2) excess is converted into glycogen in the liver and muscles
3) excess is converted to fat and stored under the skin or around organs
What happens to amino acids in assimilation?
Taken to the liver, then to the rest of the body, where:
1) they’re used by the body cells for growth and repair
2) they’re used to make hormones and enzymes
3) excess is converted to glycogen or far
4) excess is broken down or deaminated in the liver and converted to urea to be excreted
What happens to fatty acids or glycerol in assimilation?
Carried by the lymph roam the blood and are:
1) stored under the skin and around organs
2) used to make new membranes in cells and organelles
3) used for respiration in some circumstances
What happens when the blood glucose levels rise?
The pancreas secretes insulin which stimulates body cells to absorb glucose for respiration and the liver cells convert excess glucose to glycogen
What happens when blood glucose levels fall?
The pancreas secretes glucagon which stimulates the liver cells to convert glycogen to glucose
Functions of the liver
Carbohydrate metabolism- excess glucose is stored as glycogen
Production of bile
Storage of vitamins
Storage of minerals
What can result from a surplus of vitamin A
Jaundice, liver damage
What can result from a surplus of vitamin D
High levels of calcium in the blood
What can result from a surplus of calcium
Calcification of soft tissues
What can result from a surplus of sodium
Hypertension
What can result from a surplus of iron
Liver damage
Energy requirements for age, sex and occupation
Daily energy requirements:
1) increase as age increases
2) increase as activity increase
3) are higher in males
4) increase in a female when she’s pregnant or lactating
How can deficiency diseases be treated?
Increasing the intake of foods rich in the missing nutrients or foods fortified with the missing nutrient
How can diabetes be treated?
Controlled by eating a healthy, balanced diet that’s low in sugar and saturated fat and high in dietary fibre
How to treat hypertension
Controlled by eating a balanced diet that’s low in saturated fat, cholesterol and salt
Stop smoking, reduce obesity
Advantages of vegetarian diet
Less prone to obesity
Less likely to suffer from constipation
State the 5 processes of heterotrophic nutrition
Ingestion
Digestion
Absorption
Assimilation
Egestion
