Week 6 Flashcards
What is a nutrient and the 6 main nutrient groups?
A substance/chemical that an organism needs to live, grow, reproduce
6 main nutrient groups:
- Carbohydrate, lipids, protein, vitamins, minerals, water
Defintion of essential nutrient
Must be obtained from an external source,
- Either because the organism cannot synthesise it, or produce sufficient quantities
What are the four common micronutrient deficiencies?
- Iron
- Iodine
- Vitamin A
- Zinc
What are the eight micronutrient elements essential for higher plants?
Boron, chlorine, copper, iron, manganese, molybdenum, nickel and zinc
What are the two major groups of nutrients?
Macronutrients
- Large quantities
- Carbohydrates, proteins and lipids
Micronutrients
- Minute quantities
- Vitamins, minerals, and trace elements
What two forms are carbohydrates presented in?
Simple carbohydrates
- glucose, fructose, other sugars
Compound carbohydrates
- Starch in plants
- Glycogen in animals (liver and muscles)
- Polymers of glucose
- Metabolised to CO2 + H20 and energy
Structure of glycogen
- Branched biopolymer
- Linear chains of glucose residues
- Chains branching off every ten glucose or so
Structure of starch (amylum)
- Large number of glucose units joined by glycosidic bonds
- Large amount of compound carbohydrates
- Produced by all green plants as an energy store
- Staple foods:
- Potatoes, wheat, maize (corn), and rice
Function of proteins
- Building material for body parts
-Muscle, brain, blood, skin, hair, nails, bones and
body fluids. - Essential for growth, repair of worn-out tissues, and
resistance against infections.
What are the 9 essential amino acids for proteins?
histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine
Where can you source proteins?
Both animals and plant foods:
Animals:
- ‘Complete’
- Contain all amino acids
Plant Proteins:
- ‘Incomplete’
-Some low in amino acids (methionine, lysine, tryptophan)
- Supplement with grains, nuts, seeds, legumes
Structure of lipids
- Water-insoluble
- Triglycerides, phospholipids and sterols, such as cholesterol
What are lipids essential for?
− Brain, nerves and hormones, and
− Absorption, transport and storage of fat-soluble vitamins (A, D,
E and K)
How can triglycerides exist?
May be a FAT or an OIL:
Depends on predominant type of fatty acids it contains
− saturated, monounsaturated or polyunsaturated
FATS
• Predominant fatty acids = saturated and monounsaturated
-Solid at room temperature
• Triglycerides of land animal sources
OILS (Triglyceride)
- Polyunsaturated fatty acids predominate
- Liquid at room temperature
-Aquatic animals (marine fish) = polyunsaturated fatty
acids and their lipids
Triglycerides of plant sources
• Vegetable oils:
Mustard oil, soybean oil, sunflower oil, corn oil
However:
Coconut and palm oil contain large proportions of
saturated and monounsaturated fatty acids (solid at room
temp)
Vitamins
-Cannot be synthesized in body
-Essential for metabolism and utilization of carbohydrates,
proteins and lipids
- Function as co-enzymes
e.g. Vitamin C for collagen hydroxylation
Either Water soluble or fat soluble:
Water-soluble vitamins:
− B-complex vitamins (B1, B2, etc.) and vitamin C
Lipid-soluble vitamins:
− A, D, E and K
What three forms does vitamin A exist in?
Retinols
Beta-carotenes
Carotenoids
What is vitamin A needed for?
Skin, hair, eyes
Increases resistance to infection
- Immune system: T cell differentiation
Vitamin A Deficiency
Xerosis cutis (dry skin)
- Retinoic acid (RA): growth factor for epithelial (and other)
cells
- RA can control gene transcription
Low resistance to infection
Vitamin A deficiencies ( Eye disorders)
xerophthalmia (eye fails to produce tears)
− Loss of goblet cells in conjunctiva
− no mucus, debris accumulates, Bitot’s spots
(keratin) form due to dryness
• Keratomalacia
− (atrophy of corneal epithelial cells)
− opaque cornea and blindness
Night blindness
− Retinal (Vitamin A) and opsin form
rhodopsin in retina
− Rhodopsin: pigment for low light detection
Thiamine (Vitamin B1)
-Found in all tissues, especially the liver
-Essential for tissues with High oxidative metabolism:
-Nervous system
- Heart
- Involved in metabolism of acetyl CoA in mitochondria
- Thiamine = Transport form
- Phosphorylated thiamine derivatives = Active forms
- thiamine pyrophosphate (TPP)
What can cause Thiamine (B1) deficiency?
- Caused by diets of mostly white rice (common in alcoholics)
- Depression
- Poor appetite
- Skin problems
- Beriberi
Neurological degeneration (‘Dry’)
− Numbness, confusion
Cardiovascular disease (‘Wet’)
− Tachycardia, cardiomegaly, and
congestive heart failure - Muscular wasting
- Edema
Niacin (vitamin B3
AKA Nicotinic acid
Conversion of carbohydrates→ glucose for energy
production
Niacin → nicotinamide → Nicotinamide adenine dinucleotide (NAD) and NADPNAD and NADP are cofactors in many enzymatic reactions, including dehydrogenases (catabolism)
Sometimes used to lower blood lipids
-Reduced cardiovascular disease risk if on statins
-Raises HDL cholesterol