nutrition and digestion Flashcards
what is nutrition
the way an organism obtains its food
what does autotrophic mean
describes organisms that can make their own food eg plants
what are heterotrophs + 3 types
an organism that cant make its own food, herbivore, carnivore, omnivore
what are the steps of digestion
ingestion, digestion, absorption, assimilation and egestion
what is ingestion
food is taken into the alimentary canal through the mouth
what is digestion
food is broken down into soluble pieces physically and chemically so they can be absorbed into the blood stream
explain the two types of digestion
physical digestion: mechanical breakdown of food. chemical digestion: when enzymes break down food
where does physical digestion occur?
mouth by the teeth grinding, oesophagus and intestines by peristalsis, stomach by churning and muscular movement
where does chemical digestion occur
saliva in the mouth by the amylase, pepsin in the stomach, lipase in the small intestine
what are the four types of teeth
incisors, canines, premolars, molars
what is food called after leaving the mouth
bolus
what chemical digestion occurs in the duodenum
bile which is made in the liver and pancreatic juice enter the duodenum, the bile emulsifies fats and neutralises acid
what is bile
made of water, bile salts and bile pigments, no enzymes and produced from the remains of dead red blood cells
what are the islets if langerhans
specialised cells in the pancreas which produce insulin which control blood sugar levels
what occurs in the small intestine
digestion in the duodenum and absorption in the ileum
what occurs during absorption in the ileum
amino acids, monosaccharides and water soluble vitamins pass from the villi into the blood capillaries by diffusion and are carried to the liver via the hepatic portal vein. fatty acids, glycerol and fat soluble vitamins pass from the villi to the lacteal by diffusion they are then eventually brought to the liver as they are dumped into the blood. by the subclavian artery.
what are the functions of the large intestine/ colon
reabsorb water, forms faeces, produces b and k vitamins by symbiotic bacteria
what are the four parts of the large intestine
caecum, appendix, colon and rectum
what are the functions of the liver
metabolism, produces bile, detoxifies the body, stores vitamins and minerals, makes plasma proteins, produces heat, breaks down red blood cells and produces cholesterol
Describe the. Mechanical digestion in the stomach
Food is churned and broken up by
peristalsis.
Describe chemical digestion in the stomach
Gastric Juice which is secreted into the
stomach consists of: Mucus, HCL, Pepsinogen
■ Mucus- lines and protects the stomach from
digestive enzymes.
■ Hydrochloric Acid (HCL)– kills bacteria
and activates pepsinogen to pepsin. (pH1-2)
■ Pepsinogen is an inactive enzyme which
is activated by HCL to the active enzyme
Pepsin. Pepsin is a protease which breaks
down proteins into peptides.
What is the pancreas’ role in digestion
Secretes pancreatic juice (contains enzymes and
sodium bicarbonate)
■ Pancreatic Juice is secreted into the pancreatic duct
which leads to the duodenum where it is released.
Adaptions of the Ileum to its
Function:
■ Very Long (all food can be absorbed)
■ Numerous Villi and Microvilli (increase
surface area)
■ Lacteals/ Lymph system to carry fats
■ Rich blood supply to carry water soluble
products
■ Walls of villi are thin allowing rapid diffusion
Fate of amino acids, glucose and water soluble vitamins once absorbed
Amino acids, Glucose, Water soluble Vitamins:
• Liver will store glucose, converting it to Glycogen, and
stores vitamins and release them when they are needed.
• Amino acids cannot be stored so if they are not used they
are broken down to form Urea in a process called Deamination.
Fate of fatty acids, glycerol and fat soluble vitamins once absorbed
Fatty Acids, Glycerol and Fat soluble Vitamins:
• Once inside the lacteal the fatty acids and glycerol join
together to become lipids once again. The Lipids are
transported around the lymph system until it empties into
the blood at the Subclavin Vein. The lipids are now sent to the
liver to be processed
The amount of food a person requires depends on:
Age (younger people need more food than older, growing, more active)
2 Activity (less food needed if you have sedentary lifestyle, more food
needed if more active lifestyle)
3 Gender (males need more food than females)
4 Health (immunocompromised people diff. food requirements.. etc.)
Food is made up of what six chemicals
C, H, O, N, P, S
What are the three types of carbohydrates
Monosaccharides, disaccharides, polysaccharides
Monosaccharides
Single sugar units of 1 ring of carbons such as Glucose and Fructose.
Disaccharides
Two single units of sugar/monosaccharides joined together such as Sucrose and Maltose.
Polysaccharides
Many sugar units joined together i.e. Starch, Cellulose and Glycogen.
Functions of Carbohydrates
Structural Carbohydrate: Cellulose is a structural carbohydrate as it is used for its strength and support in plant cell walls.
Metabolic Carbohydrate: Glycogen is a metabolic carbohydrate as it is used as an energy store found in the liver. It can be broken down for metabolism when needed
Cellulose = fibre.
Testing for Carbohydrates
Testing for Starch: Add iodine and observe color change. Blue/black color indicates the presence of starch. Red/brown = no starch
Testing for Reducing Sugar i.e. Glucose: Add Benedict’s solution and heat to observe color change.
Brick red: glucose present
Blue: no glucose
Structure of Lipids
Lipids are made up of 1 Glycerol + 3 Fatty Acids = Triglyceride. Phospholipids have one fatty acid replaced with a phosphate.
Function of Lipids
Structural Lipids: Phospholipids make up the structure of the cell membrane.
Metabolic Lipid: Adipose tissue can be used as an energy store.
Functional Lipid: Myelin in nerve tissue helps transmit messages.
Testing for Lipids
Rub the food on brown paper. Observe for a translucent spot to determine the presence of lipids.
A translucent spot indicates the presence of lipids.
Structure of Proteins
Proteins are made up of long chains of folded amino acids. There are 20 different amino acids found in proteins held together by peptide bonds.
Polypeptide chains become folded to produce proteins.
Function of Proteins
Structural Protein: Keratin gives strength to hair, nails, and skin. Myosin is a protein found in muscle.
Functional Protein: Haemoglobin carries oxygen in red blood cells.
Metabolic Protein: Enzymes control metabolic rate in the body. Hormones regulate metabolic activity
Testing for Protein
Add Biuret’s Reagent and observe color change to determine protein presence.
Violet color indicates the presence of protein.
Blue - no protein
Two types of vitamins
Water Soluble such as B and C
Fat Soluble such as A, D, E, and K
Vitamin C - solubility, function, source, effect on deficiency
Solubility: water soluble
Function: Vitamin C is very important for the building and maintaining of connective tissue e.g. skin, blood vessels, bone, tendons, cartilage, ligaments, teeth, gums. (needed for the absorption of iron into body and immune system also)
Source: Citrus Fruits, Green vegetables
Vitamin D - solubility, function, source, effect on deficiency
Solubility: Fat soluble
Function: Vitamin D is needed to absorb calcium and phosphate the intestines from our food thereby it is important for healthy teeth and bone formation and maintenance.
Source: fish oils, egg yolk, milk, skin makes Vitamin D in sunlight.
Deficiency: Rickets in children and Osteomalacia in Adults. (bones are deformed and weak, easily breakable)
Minerals In Animals
Calcium and iron
Minerals in Plants
Calcium and magnesium
Water
❖Excellent Solvent and Medium for all Chemical reactions
❖Involved in chemical reactions (photosynthesis, respiration)
❖Transport (plasma in blood, cytoplasm in cell)
❖Regulates Body temperature by dispersing heat through the blood
Source and function of calcium in animals
Source: Found in dissolved salts in Dairy Produce.
Function: Formation and Maintenance of healthy Bone and Teeth
Source and function of iron in animals
Source: Found in Red Meat, Offal, Spinach, Dark Green Veg.
Function: Needed to produce Haemoglobin in R.B.C.’s to
transport oxygen around the body.
Source and function of calcium in plants
Source: Found in dissolved salts in water in soil.
Function: Formation of Calcium Pectate in Cell walls.
Source and function of magnesium in plants
Source: Found in dissolved salts in water in soil.
Function: Needed to produce chlorophyll structure which is
the green pigment involved in Photosynthesis.
