Biology 11 Digestive system Flashcards Preview

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Flashcards in Biology 11 Digestive system Deck (52):

Epithelial Tissue

• Covers entire surface of body
• Skin, columnar
• Description: thin layers of TIGHTLY packed cells covering surfaces and lining internal cavities
• Cells closely packed and have one or more layers
• Form the covering or lining of all internal and external body surfaces
• Function: protects underlying tissue, secretes chemical substances, absorbs nutrients from digesting food, excrete wastes from kidney and promotes diffusion of gases
• May secrete mucus
• Found in stomach, capillaries, alveoli


Muscle Tissue

• Description: Bundles of long cells containing protein capable of contracting (shortening)
• Types: cardiac (found in heart), skeletal, visceral (smooth)
• Function: allows muscles to contract
• Found in bronchioles, heart (cardiac) small intestine (smooth)


Connective Tissue

• Description: various types of cells held together by a liquid, gel, or solid, known as a matrix
• Cells are scattered throughout the extracellular matrix of protein
• Types: cartilage, bone, blood, adipose, lymph, fat
• Function: to connect →supports and binds other tissues


Nerve Tissue

• Neurons are basic unit
• Description: long thin cells with finely branching ends capable of conduction electrical impulses
• Function: sensing stimuli and transmitting signals to and from different parts of the organism


Nutrition: Purpose of eating/importance

• To provide materials for growth and maintenance of our bodies
o Raw materials for growth and maintenance come from nutrients: Chemicals that an organism needs in order to grow, build, and repair tissues
• 6 classes of essential nutrients: Carbohydrates, proteins, lipids (fat), water, minerals, and vitamins
o In the body, nutrients are broken down into simpler molecules
• These are then used to build bone, muscle and tissues
• To provide energy for all biological processes and activities
o Nutrients provide energy
o Light energy is converted to chemical energy by photosynthesis→plants
• Chemical energy can be stored in cells and released when needed by – cellular respiration (release energy)
• At all times your body requires energy to do task either simple or complex
• Heart beating, breathing, brain processing, muscles contracting or relaxing to hold you up, transfer of thermal energy etc.
o Food →energy→converted to other forms of energy
• Spend about 12.5% of each day eating


Types of metabolism

Catabolism-involves the breakdown of materials in an organism

Anabolism-Involves the building of larger, more complex molecules from smaller, simpler molecules
-Use of materials and energy provided by catabolic processes to build complex materials needed for growth and repair


Metabolic rate vs basal metabolic rate

Metabolic rate: Rate at which the body converts stored energy into working energy
-body size, physical activity, hereditary factors, age, sex/gender

Basal Metabolic Rate (BMR): Rate at which energy is used by an organism when it is at rest →part of metabolic rate


Energy requirements in general

Body needs and uses energy to perform daily functions

oEnergy requirements are not the same each day, varies with type and amount of activity

Lean/muscle: requires and burns more energy than fat


Macro and micro nutrients

Macronutrients: energy-providing nutrients that are consumed in large quantities
• Carbohydrates
• Proteins
• Lipids
Micronutrients: energy-providing nutrients that are consumed in small quantities
• Vitamins
• Minerals



• Main source of energy for the body
oCan easily turn carbohydrates into energy than fats
• Made up of carbon, hydrogen and oxygen (carb,o, hy)

Three main types
oMonosaccharides (simple sugars):
• Ring shaped (one ring)
• Many used in cellular respiration
• Glucose into carbon dioxide →humans making energy
• Examples: Glucose (universal sugar), Fructose
• Two simple sugars together
• Examples: Lactose (milk sugar), Sucrose (table sugar)
• Complex carbohydrates
• Can be up to as many as hundreds of simple sugars joined together
• Examples include Starches (bread, pasta etc.), Cellulose (plants), Glycogen (storage molecule)



Chains of amino acids

• Important structural molecules
• Involved in all metabolic processes (how we create energy)
• Generate motion
• Some are hormones (HgH)
o Chemical messengers released by cells that influence other cells to act
• Control chemical reactions
• Transport oxygen
• Defense (antibiotics produced by immune system)

o Made up of long chains of amino acids
o Highly variable in size and shape
o 20 different amino acids that are used to build proteins
• 12 can be made by the body, other 8 must be obtained from the diet (essential amino acids)
• Animal proteins contain all 8 essential amino acids
• Therefore animal muscle (meat) has higher concentration of protein than plants (fruits and vegetables)
Sources: Meat, Eggs, Fish, Cheese, Beans, Lentils, Seeds, Nuts



55% carbohydrates (can be stored as glycogen)
10-30% protein
No more than 30% lipid (can cause health problems)
2L water per day



Includes fats and oils, wax, phospholipid, steroids
o Fats: lipids with one, two or three fatty acids bonded to a glycerol (alcohol)

• Difficult to get energy, not as easy as getting energy from carbohydrates
• Concentrated source of energy for the body
• Help in absorption of vitamins
• Lipids are main components of all cell membranes →maintaining
• Insulation (Fat generate heat)
• Includes certain hormones (sex)-->fat based

o Varies in structure
o Many lipids incorporate fatty acids: small organic molecules consisting of a hydrocarbon “tail” with “head”
o Three fatty acids joined to a glycerol molecule
Triglyceride: Saturated or unsaturated
• Saturated: usually solid at room temperature (meat and butter) -BAD (excessive harmful)
• Unsaturated: usually liquid at room temperature (oils) -GOOD
oPolyunsaturated →omega-3 & omega 6 fatty acids
oMonounsaturated →olive oil

• Transfat (trans fatty aids/hydrogenated fats)
o Solid at room temp.
o Excessive harmful (ex: heart disease)

Essential fatty acids
o Not produced by the body, but necessary
o Obtained from Omega-3 fatty acids
o In unsaturated fats
• Help to prevent heart disease and arthritis
• Found in oily fish, nuts, seeds, leafy greens
Steroids (lipid based)
o Include the sex hormones (testosterone, estrogen)
o Includes hormone – cholesterol (Cholesterol (steroid) determines if cell membrane is fluid or solid)
• Key component of all animal cell membranes



Function is to regulate cell function, growth and development
• Fat soluble (A,D,E,K) or water soluble (B,C)

o Do not dissolve in water
o Not easy to eliminate from the body if they are excess (toxic)
o Can come from food, but A,D, K are produced by body as well

o Cannot be stored in the body, readily excreted by the body
o Must be replenished daily by diet (cannot create from body)
-Fat: difficult to eliminate; water: easier to eliminate)
-Produce v.s. Eat



• Naturally occurring elements
• Used to carry out metabolic processes and to build or repair tissue, and nerve function
• Calcium and phosphorus
o Bone structure
• Iron
o Blood-Iron is key component to transport oxygen in blood
• Oxygen
o Hemoglobin: pigment in body that transports oxygen (carrier)


Balance in diet

•Body mass: average energy output must equal average energy input

energy intake = energy output

Anorexic (from weight loss): energy intake < energy output
Obesity (from weight gain): energy intake > energy output

-must adjust to certain circumstances (increase in energy for increase in physical activity)


Imbalance in diet

-result in several health problems

Obesity: excessive amount of body fat
-can lead to heart problems, diabetes, cancer, high blood pressure etc.

Anorexia Nervosa: psychological disorder
- severe malnutrition
-cause: over exercising with little energy intake, use of laxatives/diet pills, starve to lose weight

Bulimia: eating a lot then throwing up
-binge then purge
•Binge: rapid consumption of large amounts of high calorie food in short period of time
•Purge: vomiting
o Most likely suffer from anorexia as well

Anorexia and bulimia difficult to treat:
-psychological disorder
-once eating cycle is disrupted, it is very difficult to return to normal state
-often in secrecy


Digestive system structures

Mouth/oral cavity
oTeeth: mechanical digestion →break down food into smaller bits
oTongue: mixes food with salivia
oSalivary Glands: produces saliva that contain digestive enzymes (amylase-breaks down carbohydrates)
• Saliva: water, mucus, enzymes
• Moistens food and begins process of carbohydrate digestion

Pharynx (throat)

Epiglottis: keeps food from entering the trachea

Esophagus: muscular tube through which food moves to the stomach

Cardiac sphincter/gastroesophageal : located at end of esophagus; controls entrance of bolus into stomach

Stomach: J-shaped muscular sac that receives food and mixes it with gastric fluid secreted by cells in its lining. Also controls movement of food to the small intestine (pyloric sphincter)

Liver: filters toxins
oProduces bile- breaks down fat
oBile: emulsification-suspension of fat droplets in a fluid

Gall bladder: stores bile (help breakdown food) →secretes bile into small intestine

Pancreas: gland-secrete digestive juices, enzymes, and bicarbonate into small intestine. Also create and hold hormones

Small Intestine: long
oDuodenum: receives secretions from liver, gall-bladder, and pancreas →aid digestion
oJejunum & ileum: Absorption occurs across the highly folded wall (villi and microvilli)

Large Intestine: wide
oAbsorbs remaining water
oForms feces from waste and undigestables

Rectum: expandable sac that stores feces

Appendix: accessory organ (do not need)

Anus: opening at the end of the digestive tract where feces are expelled


Nutrition intake (from mouth to anus)

1.Ingestion (taking in food)
• Prepares food for absorption (by breaking food into smaller, absorbable molecules)
• Mechanical and chemical breakdown of food
• Small intestine
4.Egestion→eliminating undigested or waster products


Enzymes in body

Purpose: to break down substances
How? by increasing the rate of reactions
• Enzymes are protein catalysts (consists of protein that accelerates reaction time)
Definition: protein or RNA that speeds up a chemical reaction without being changed by it
• Enzymes are made up of protein, but not necessarily break down protein (those are called proteases)

• Enzymes are specific to substrates (can be anything (nutrient, food, molecule etc.)
Definition: protein or RNA that speeds up a chemical reaction without being changed by it
o Enzyme attach to substrate it wants to break down and then break down→chemical reaction
o Every enzyme has a specific substrate

• Enzymes all have optimum environments in which they work best
o Temperature (human enzymes work best at 37 degrees)
o Light (plants)
o pH
o Salt concentration


Types of enzymes

-produced by salivary glands
-Present in saliva (found in mouth)
-F: breaks down starch (complex carbohydrate) from polysarchides to disarchides

Pepsin: Protease
-produced by stomach
-present in stomach; activated in low pH (1-2)
-F: breaks down protein
*pepsinogen (inactive)

-produced by pancreas
-Present in small intestine
-F: breaks down carbohydrates

-produced by pancreas
-present in small intestine
-F: breaks down fat/lipid into fatty acids and other components (needs help of bile)

Trypsin: protease
-produced by pancreas
-present in small intestine; activated in high pH (8)
-F: breaks down protein in small intestine


Other secretions in body

Other secretions
-produced by liver (stored in gall bladder)
-Activated in small intestine
-F: breaks down fat

-produced by stomach
-present in stomach
-F: lower pH levels for pepsin


Digestion process 1) start - epiglottis

starts in mouth

•Food is broken down into smaller pieces by teeth/chewing (physical/mechanical breakdown)
o Incisors and canines are for grabbing/cutting
o Molars and pre-molars are for grinding and crushing
•Presence of food in the mouth or smell of food triggers salivary glands to produces saliva
o Saliva contains enzymes that increase the rate of chemical reactions and break food down (catalyze reactions)
• Amylase (enzyme) breaks downs starch (polysaccharides) into smaller disaccharides (chemical digestion)
• After the bolus is formed, the tongue pushes it towards the back of the mouth where it is swallowed→swallowing forces food into pharynx

o Epiglottis flops up to block trachea (blocking route to larynx)
• Bolus passes pharynx and then enters the esophagus.
• The soft palate is raised to prevent food from entering the nasal passages (uvula also blocks nasal passages)
• At the same time the larynx is raised against the flap of tissue called the epiglottis: both cover the passageway to the trachea


Function of saliva (consists of)

Saliva dissolves food particles → able to taste food
o Saliva contains mucus to aid in swallowing
• Mucus: slimy; helps lubricate food (so that it can slide down/move and swallow)
o Saliva moistens the food into a bolus
o Saliva: water, amylase enzyme, mucus
*Produce 0.75 – 1.5 L of saliva a day


Movement of food bolus to stomach

Esophagus: Long muscular tube connecting pharynx and stomach
•Carries food from pharynx to stomach using peristaltic/muscle contractions (peristalsis)
•Cardiac sphincter (gastroesophageal) at junction prevents food in stomach from going back into esophagus
oRelax (allow food to enter stomach) and contract (prevent)


Stomach structure

• J shaped
• Expand in size to store up to 2L of food (due to rugae folds in muscosa layer)
• Stores food and controls rate of passage to SI, secretes acids and enzymes for chemical digestion, mechanical digestion

Structure stomach:
o Nerve endings in the lining of stomach are then stimulated to increase muscular contractions/mechanical digestion (to form chyme)

4 Layers of stomach: responsible for both chemical and physical digestion
o Innermost layer is extensively folded
o Secretes gastric juice (digestive enzymes, HCl acid and mucus→protects walls from acid)
o Epithelial cells here divide rapidly (every three days lining is replaced)→epithelial lining
o Layer of connective tissue (nerves and blood vessels)-->supplies blood and nervous tissue to stomach
o Smooth muscle churning the food and mixing it with gastric juices producing the chyme ßend product
o Smooth outer layer
o Holds the stomach in place


Small Intestine function, structures

-absorption (main site 80%)

-Breaks down large molecules into smaller, absorbable subunits (e.g.: amino acids, monosaccharides, fatty acids, monoglycerides)
-Amino acids and monosaccharides absorbed from gut enter blood vessels

Chemical Digestion (in duodenum) of lipids, proteins, carbohydrates (enzymes secreted by liver, gall bladder, and pancreas)

23 feet in length (longer than large intestine)

Includes: duodenum, jejunum, ileum
-folds, villi, microvilli <-- lymphatic system then bloodstream)


Digestion in Stomach

-nerves (submucosa) sense food
-Initiate release of HCl (gastric juice) --> inhibits amylase (no digestion of carbohydrates), lowers pH, which activates pepsin from pepsinogen
-pepsin breaks down proteins into amino acids

-Churning: Nerve endings in the lining of stomach are then stimulated to increase muscular contractions/mechanical digestion (to form chyme)


Application of stomach (problems)

•Acid reflux: gastroesophageal sphincter not closed entirely →food chemically digested to go back up the esophagus →burning of lower throat

•Ulcers: Helicobacter pylori bacteria makes holes in muscosa by preventing the production of mucus


SI: duodenum

-first part of SI
-25 to 30 cm

When acidic chyme (pH 2.5) enters SI:
•Prosecretin (hormone) is converted into secretin →activated by gastric acid
•Secretin stimulates the liver to make more bile and encourages the pancreas to release bicarbonate ions →to raise pH level of chyme for digestive enzymes to function -->neutralization to pH 8-9
-(Secretin controls pancreatic bicarbonate secretion, regulates the entering of more food into the SI from the stomach until the current batch is digested (pyloric sphincter)

-basic pH deactivates pepsin, but activates trypsin from trypsinogen -->continue protein digestion

-protein digestion by trypsin and other enzymes
oEnterokinase (enzyme in duodenum) converts trypsinogen into active trypsin

-Enzymes break disaccharides into monosaccharides (breakdown of carbohydrates continue)→mono enter blood
(amylase in mouth breaks from poly to di, then carbohydrase breaks down di to mono/simple)

-lipase enzyme (from pancreas) + bile break down lipids into fatty acids and lipid components
o Lipases cannot break down large chunks
o 1: bile breaks down fat into smaller pieces
o 2: lipase breaks into smaller components


Pancreas function

o Secretes enzymes
o Secretes hormones (regulation of glucose in blood)

Fat-rich chyme signals release of hormone cholecystokinin (signalling hormone)
-CCK signals the pancreas to secrete a variety of substances (pH controllers for lipids, carbs, proteins), gall bladder to release bile into small intestine

Via pancreatic duct -->Slows stomach digestion – digestion of fats by SI (for Efficient absorption)


In summary of pancreas + SI

Stomach chyme in small intestine→CCK sends signals to Pancreas to secrete proteases→secretin tells liver to make more bile and signals pancreas to release bicarbonate (CCK causes gall bladder to release bile) = neutralize acid & basic pH→pepsin no longer active→enterokinase converts trypsinogen into active trypsin→continue protein digestion

*CCK senses fat-rich chyme and signals pancreas and liver that SI needs substances. Then, secretin tells liver to make more bile. CCK = broad
Secretin = specific to LIVER


CCK and Secretin

*CCK senses fat-rich chyme and signals pancreas and liver that SI needs substances. Then, secretin tells liver to make more bile. CCK = broad
Secretin = specific to LIVER

Acid stimulates the conversion of prosecretin to secretin
*both slows down digestive process so that it can be ready to be absorbed. Secretin stimulates release of bicarbonate rich fluid from the pancreas to counteract the acid

Fats stimulate the secretion of CCK. CCK stimulates pancreatic enzyme section like amylase and lipase ( aid in breaking down food) It also causes contraction of the GALLBLADDER, which releases bile into the duodenum.


Liver structure, function, importance

• Largest internal gland/organ
• Location: underneath diaphragm

Function: detoxifies dangerous substances and stores vitamins and glucose (stored in liver as glycogen)
• To produce and secrete bile →emulsifies FAT by breaking them down into tiny droplets (called micelles) -->lipase break down micelles
1: bile breaks down fat into smaller pieces
2: lipase breaks into smaller components

•Liver can break down stored glycogen and release its glucose subunits into the blood→fuel for brain (only use glucose)

Importance: blood with nutrients absorbed from capillaries in the SI travel to liver to REMOVE TOXINS before going to heart

Gall bladder: stores and concentrates bile from liver
•CCK sends bile to SI to digest fats


-what is absorbed

Carbohydrates, proteins, lipids, vitamins, minerals, water (wastes are not absorbed and are later expelled)

Nutrients mainly in SI Jejunum and ileum
Water absorbed in LI

absorption via folds in mucosa layer of SI with villi and microvilli (maximize SA)

Types of absorption:
oPassive transport: Diffusion, osmosis, facilitated diffusion →nutrients enter bloodstream via diffusion
-also filtration (not in intestines, in kidney)
• High to low concentration (concentration gradient)
• No energy required
oMonosaccharides are transported by proteins in the membrane into the cells lining the SI →use facilitated diffusion because too large
oActive transport: for large molecules, need energy (ATP)
• Low to high concentration
• When protein pumps a solute across a cell membrane against the concentration gradient
• Opposite of passive transport (down concentration gradient)


Large intestine structure, function

• Large in diameter 7.6 cm
• Only 1.5 m in length
• Consists of “appendix”, cecum, colon, rectum, anus:
oCecum receives processed material from the SI (first part of LI)
oColon is largest (ascending, transverse, descending, sigmoid)
oRectum holds waste products (last 20 cm of LI)
oAnus is the external opening
o*Cecum connects to s. intestine, passes through colon, then rectum, then anus
• Waste slowly moves through colon
• E. coli in large intestine colon(makes vitamin B12→absorb)

Main: to absorb water →Most digestion and absorption of nutrients is complete already
-Compacts unabsorbed material into feces (ie cellulose)→cannot digest and do not need
o *colon concentrates, stores, and eliminates wastes
• Bacteria produce vitamins (absorbed along with vitamins and minerals from diet (B, K, Na+, Cl-))
o Moderate pH in LI due to wastes moving slowly through colon

Nervous system controls sphincter at the anus


Egestion stage
-importance of undigestables

• Undigestables importance: Provide bulk and feeling of ‘full’
o Fibre helps to retain water →cannot be digested
• Feel full, water retains and makes getting rid of wastes/stool smoother


Problems relating to egesting wastes

Absorption of water changes the liquid in the colon to a soft solid called feces

oConstipation: Too much water back into blood from LI (too much fibre)
• Colon absorbs too much water, leaving little water in feces (make harder for feces to be eliminated)
• Hardened, small, dray feces
• Typical causes (not related to water absorption): inadequate water intake, inadequate fibre intake, stress, dehydration →fewer than 3 times/week
o Diarrhea: Too little water absorbed back into blood (lead to dehydration)
• Diarrhea dehydrates body
• Protective mechanism: Flush foreign substances from body
Causes: Common infecting agents
• Salmonella, Campylobacter, E. coli through contaminated food or water usually

* The more water you absorb, the more solid/compact the poop becomes


Digestive disorders Nausea and Vomitting

o Unpleasant feeling
o Mouth may start to water, stomach feels upset
o Cold sweats
o Pale
o Often precede vomiting but not always
• Inner ear (motion sickness), drugs (alcohol), infections (food poisoning), brain (tumour), injury (concussion), diseases (cancer)

o Protective mechanism to remove toxins
o Strong muscular contractions of diaphragm and stomach that force contents up through esophagus →contract inwards to push
o Breathing ceases as the larynx and epiglottis close opening to trachea
o Signals to vomit come from brain
o Risks of vomiting: esophageal tears (prolonged vomiting), vomitus goes to respiratory tract (asphyxiation-to die or lose conscious due to impaired normal breathing), dehydration (no fluids)
• Inner ear (motion sickness), drugs (alcohol), infections (food poisoning), brain (tumour), injury (concussion), diseases (cancer)


Digestive disorder Crohn's Disease

Crohn’s Disease:
• A type of Chronic inflammatory bowel disease

• Formation of tiny open sores or ulcers on the surface of the lining (bleeding and produce pus and mucus)
• Condition in which the walls of the gastrointestinal (GI) tract become irritated, inflamed and swollen (mouth, esophagus, stomach, small intestine, large intestine, and rectum)
o Common in small and large intestine

Another type is ulcerative colitis (only colon)
•Causes inflammation in the large intestine

• Abdominal pain (stomach/ab area)
• Intestinal bleeding.
• Diarrhea.
• Nausea & vomiting.
• Loss of appetite.
• Weight loss.
• Fever.
• Possible hereditary link to autoimmune disease (25%).
• Possible bacterial or viral infection.
• Barium x-ray.
• Colonoscopy: endoscopic examination (using camera) of the lining of the large intestine (rectum and colon)
Treatment: no
• Only can get medication to control inflammation etc.
• Avoidance of “trigger foods”.
• Removal of blocked segments.


Digestive disorder Stomach/gastric cancer

Stomach/gastric cancer
• Cancer of the tissues that line the stomach
Causes unknown, risk factors: H. pylori infection, Smoking, Poor diet.
•Often non-specific
o Nausea and vomiting.
o Heartburn and indigestion.
o Fatigue.
o Stomach pain.
o Feeling full after eating little.
• Endoscopy & biopsy (medical test where piece of tissue or sample cells is removed from body)
• CT scans: takes data from variety of x rays to create cross section images
• Barium Swallow X-ray: barium (sulfate) swallowed before x ray, used to determine what is the cause of swallowing issues →upper GI tract (barium highlights certain areas on X ray to make it clearer, X ray cannot take pictures of upper GI tract)
• Radiation therapy & chemotherapy
oTo shrink tumor.
• Gastrectomy: surgery to remove parts (partial) or all of stomach


Digestive Disorder Cirrhosis

• Liver disease/scarring
• Leads to loss of liver function.
• Chronic damage to liver (e.g., hepatitis & alcoholism).
• Fatigue
• Loss of appetite.
• Easy bruising & bleeding.
• Nausea & vomiting.
• Fluid retention (when body cannot get rid of excess fluid) in abdominal region.
• Blood tests.
• Liver Biopsy.
• CT or MRI scan (scan patients in long tube).
• Ultrasound (images ex: baby in belly)
• Damage cannot be reversed
• Avoidance of alcohol
• Liver transplant


Diagnosis technology

X ray
1) Barium X ray: patient drinks barium liquid
2) Barium swallow x ray: barium highlights upper GI tract
Endoscopy: Use of a camera to look inside interior of hollow organs or cavities

Colonoscopy: endoscopic examination (using camera) of the lining of the large intestine (rectum and colon)

Biopsy: medical test where piece of tissue or sample cells is removed from body

CT scans (Computerized tomography): takes data from variety of x rays to create cross section images

MRI scan: scan patients in long tube

Radiation therapy: using radiation to damage cancer cells

Chemotherapy: for cancer treatment that uses chemical substances

Gastrectomy: surgery to remove parts (partial) or all of stomach

Colectomy: surgery to remove parts or all of the colon

Blood tests: extracting blood sample from vein

Ultrasound: images ex: baby in belly


Essential nutrients summary

-Major source of human energy
-Easily digested
-Cheaper source of energy than fats or proteins
-Made of carbon, hydrogen and oxygen
-Main dietary sources: bread, pasta, crackers, cereals, potatoes, corn, peas, fruits, sugar, and syrups
-Carbohydrates should make up 40% - 55% of the daily diet.

-Provide the most concentrated form of energy but are a more expensive source of energy than carbohydrates
-Made of carbon, hydrogen, and oxygen but contain more oxygen than carbohydrates
-Maintain body temperature by providing insulation; cushion organs and bones; aid in the absorption of fat soluble vitamins; provide flavor to meals
Two classifications of fats:
i. Saturated: fats that are solid at room temperature (shortening)
ii. Unsaturated: fats that are liquid or soft at room temperature (oils)
Cholesterol: a fatty substance found in body cells and animal fats and also manufactured by the liver. An excess can contribute to atherosclerosis
-Main dietary sources: butter, margarine, oils, cream, fatty meats, cheeses, and egg yolk
-Daily diet should consist of no more than 25% - 30% fat.

-Basic components of all body cells
-Essential for building and repairing tissue, regulating body functions, and providing energy and heat
-Made of carbon, hydrogen, oxygen, nitrogen, and some also contain sulfur, phosphorus, iron and iodine
-Proteins are made up of 20 building blocks called amino acids:
i. Complete proteins: contain 8 of the amino acids that are essential to life. Found in meats, fish, milk, cheeses, eggs (animal products)
ii. Incomplete proteins: contain any of the remaining 12 amino acids and some of the 8 essential amino acids.
-Found in vegetable foods such as cereals, soybeans, dry beans, peas, and peanuts.
-Daily diet should consist of 10% - 30% protein

-Vitamins are organic (living) compounds that are essential to life
-Vitamins are important for metabolism, tissue building, and regulating body processes
-Vitamins allow the body to use the energy provided by carbohydrates, fats and proteins
-Only small amounts of vitamins are required; a well balanced diet usually supplies adequate amounts
Vitamins are classified as one of two types:
i. Water soluble: dissolve in water, are easily destroyed by cooking, air and light (vitamin C and B complex)
ii. Fat soluble: dissolve in fat, can be stored in the body, are not easily destroyed by cooking, air and light, (Vitamins A,D,E,K)

-Minerals are inorganic (non living) elements found in all body cells
-Minerals regulate body fluids, assist in various body functions, contribute to growth, and aid in building tissues

-Water is found in all body tissues
-Water essential for the digestion (breakdown) of food, makes up most of the blood plasma, helps body tissues absorb nutrients, and helps move waste material through the body.
-The average person needs 6 to 8 glasses of water each day (body composed of 60% water)


To calculate how long (time) one must perform one of the above activities to use up certain amount of energy

• Identify activity and amount of energy must use up
• Take amount of energy one would use for 1 kg/h (number in chart) *multiply by the weight →how much energy in kJ the activity burns for ____kg/h
• Take amount of energy must use up divide by the _____kg/h
o kJ cancel, leaving only hours
• result = hours →convert to minutes if decimal


Factors that determine how much an animal needs to eat

-body size
-physical activity


Measuring energy

Measuring energy:
• Joules (1000J = 1KJ)
• calorie – amount of energy required to raise the temperature of 1g of water by 1 degree Celsius →Food energy is generally referred to as a Calorie
o 1 C = 1000 calories or 4180 J
o Calorie (food energy-kilocalorie) and calorie (amt of energy raise temp.) different


Purpose of pre-enzymes

Body does not need to digest food all the time, therefore
-Pre-enzymes allows body to not use up unnecessary energy when digestion is not occurring.
-Without Pre-enzyme: body would be using energy when it could be conserved


Factors that help estimate person's BMR

-size (height)

*different from energy consumption


Canada's Food Guide

Need balance of food from each food group

Fruits and vegetables: 7-8 servings
Grains: 6-7 servings
Milk: 3-4 servings
Meat: 1-2 servings


Vitamin list

Vitamin A: used in synthesis of visual pigments, bone, teeth; maintains epithelia
• Lack: vision issues (blindness)

Vitamin B: many are coenzymes, help connective tissue formation

Vitamin C: for growth and development for bone, cartilage, and teeth
• Lack: scurvy: poor wound healing; impaired immunity

Vitamin D: allows for absorption of calcium, iron, magnesium, and zinc; promotes bone growth
• Lack: bone issues (softening)

Vitamin E: protects cell membranes from damage
• Lysis of red blood cells; nerve damage

Vitamin K: important role in blood clotting and building strong bones
• Lack: Abnormal blood clotting (severe bleeding)


What is molecular gastronomy

science of cooking
-investigates the physical and chemical transformations of ingredients that occur in cooking
-looks at the social, artistic and technical components of culinary and gastronomic (food) phenomena