Nutrition and Digestion

Question 1

enzymes

Answer 1

biological catalysts made of protein , lower the energy of activation for a reaction- make it more likely- join to the substrate at the active site to form an enzyme- substrate complex

Question 2

synthesize

Answer 2

reactions can put molecules together

Question 3

hydrolyze

Answer 3

reactions can take molecules apart

Question 4

factors effecting enzyme reactions

Answer 4

pH- many enzymes have an optimal pH
substrate concentration- increasing substrate concentration increases enzyme activity until all of the active sites are occupied
temperature- enzymes have an optimal temperature, when outside the optimal range they become denatured (no longer function)

Question 5

cofactors

Answer 5

are molecules or atoms that aid enzyme function, often metals, bind to enzyme or substrate

Question 6

coenzymes

Answer 6

most vitamins are organic coenzymes
also attach to enzymes- aid in binding with substrate

Question 7

competitive inhibitors

Answer 7

molecules that have a shape similar to the substrate and bind to the active site of an enzyme to prevent the desired reaction
ex) CO ci to the binding of oxygen to red blood cells
ex) cyanide blocks enzymes in mitochondria

Question 8

noncompetitive inhibitors

Answer 8

bind to enzyme but not at active site, instead at an allosteric site
changes the shape of active site so the sunstrate can not bind
ex) penicillion blocks enzymes in bacteria

Question 9

feedback inhibition

Answer 9

the inhibition of an enzyme by the final product in the metabolic pathway 2

Question 10

precursor activity

Answer 10

is the activation of the last enzyme in a metabolic pathway by the initial substrate

Question 11

allosteric activity

Answer 11

is the change in an enzyme caused by the binding of a molecule- this may promote or prevent enzyme activity

Question 12

catabolic reactions

Answer 12

breaking down substances in metabolism

Question 13

anabolic reactions

Answer 13

building complex substances in metabolism

Question 14

polymers

Answer 14

compunds made up of 3 or more subunits, which are joined by dehydration synthesis (removing water to make a bond)

Question 15

monomers

Answer 15

compounds made up of single subunits which can be produced by the hydrolysis of polymers

Question 16

carbohydrates

Answer 16

the most important energy source
made of carbon, hydrogen, and oxygen
all sugar molecules made up of either 6 ring hexose base or 5 ring pentose base
ex) glucose, sucrose, fructose

Question 17

monosaccharides

Answer 17

simple single sugars compounds composed of single sugar units- carbohydrate

Question 18

disaccharides

Answer 18

2 monomers joined together by dehydration synthesis reaction- carbohydrate

Question 19

polysaccharides

Answer 19

when many subunits join together to form a long chain- stored glucose for plants, found in cell walls of plants, stored glucose for animals- carbohydrate

Question 20

benedicts test

Answer 20

test for carbs- detects reducing sugars- turns from blue to orange when reducing sugars are present

Question 21

starch test

Answer 21

test for carbs- detects the presence of complex carbohydrates or starch- iodine is added and creates a blue black iodine starch complex

Question 22

lipids

Answer 22

water insouluble
composed of glycerol and fatty acids- combined by dehydration synthesis
carbohydrates are converted to fat
store energy
key component of cell membranes
insulator

Question 23

triglycerides

Answer 23

lipid- made from glycerol and three fatty acids ex) saturated- fats from animals, all single C-C, unsaturated- oils from plants, double or triple C=C

Question 24

phospholipids

Answer 24

lipids- phosphate molecule attached to the glycerol, cell membranes

Question 25

waxes

Answer 25

long fatty acid chains, insoluble in water so ideal for water proofing

Question 26

translucense test

Answer 26

lipid- lipids cause brown paper bag to become translucent, non-lipids do not

Question 27

sudan IV test

Answer 27

lipids- lipids dissolve in the sudan IV indicator, turning it from black granular to a pink or red paste

Question 28

proteins

Answer 28

essential for building and repairing cell structures, antibodies and enzymes are proteins polymers made up of combinations of 20 different amino acid joined together by dehydration synthesis- amino acids held together by peptide bonds

Question 29

4 types of protein

Answer 29

1) primary protein- amino acids are in a linear structure 2) secondary protein- helical or folded sheet 3) tertiary protein- further folding of polypeptide creates a small globular structure 4) Quaternary structure- a large globular structure

Question 30

coagulation

Answer 30

a protein may be denatured if exposed to heat, radiation or differnt pH coagulation is a permanent change in protein shape ex) boiling an egg

Question 31

biuret test

Answer 31

proteins- when the blue biuret is added to proteins, the peptide bonds turn the biuret a purple colour.

Question 32

digestion order

Answer 32

ingestion: taking substances into the body digestion: breaking down food to release nutrients absorbtion: absorbing nutrients into the bloodstream egestion: causing substance to leave the body

Question 33

types of digestion

Answer 33

mechanical: breaking food into smaller particles - no chemical change chemical: breaks bonds in molecules- allows molecules across cell membranes

Question 34

the mouth

Answer 34

teesth- mastication (chewing) mechanical digestion to increase surface area of food

Question 35

salivary glands

Answer 35

three on each side contains: water, mucous, anylase

Question 36

amylase

Answer 36

starts the digestion of starch chemical digestion bolus- food and saliva

Question 37

pharynx

Answer 37

common area at the back of the throat that divides into two tubes: esophagus- food tube trachea- windpipe

Question 38

epiglottis

Answer 38

a valve that blocks entrance to lungs when swallowing

Question 39

esophagus

Answer 39

moves food down to the stomach uses muscular contractions called peristalsis

Question 40

stomach

Answer 40

entrance and exit controlled by spintchers - cardiac/esophageal spintcher- between esophagus and stomach pyloric- between stomach and intestine

Question 41

stomach secretions

Answer 41

food and gastric jucies combine to make chyme. Rugae- folds in mucosa to increase surface area gastric pits- have cells at the bottom to secrete hcl, pesinogen, mucous hcl- kills bacteria, mechanically digests, activate pepsin pepsin- activated upon exposure to acids, breaks proteins into polypeptides

Question 42

ulcers

Answer 42

if mucous linning breaks down, acid and pepsin can digest mucousa- may be due to bacteria in stomach

Question 43

small intestine

Answer 43

duodenum, ileum, jejnum- 80% of digestion and absorbtion occurs here- 6 meters long

Question 44

villi

Answer 44

intestinal lining covered with villi and micro villi, to increase surface area for absolution, enzymes attach to surface 1) capillary bed- absorbs sugars and amino acids 2) lacteal (lymph vessels) absorb fats

Question 45

small intestine enzymes

Answer 45

trypsinogen- axctivated by small intestial enzyme to become trypsin- breaks long chain peptides into shorter chains. erepsin- breaks peptides into amino acids sucrase, maltase, lactase- break dissacharrides into monosaccharides amylase- breks starch into maltose and glucose. lipase- breaks fats into glycerol and fatty acids bile- emulsifies fats

Question 46

the pancreas

Answer 46

pancreatic duct connects pancreas to duodenum - secretes pancreatic jucies to the small intetine which contain- bicarbonate solution (netralizes stomach acid), trypsinogen, erepsin, lipase, amylase, lactase, sucrase

Question 47

the liver

Answer 47

- deamination of amino acids -stores glucose as glycogen, stores vitamins -destroys old red blood cells -hemoglobinin rbcs converted to bilirubin -synthesizes bile

Question 48

gallbladder

Answer 48

stores bile until fat enters small intestine, then goes to the small intestine- can become blocked with gallstones-made of cholesterol

Question 49

hepatic portal system

Answer 49

blood flows directly from small intestine to liver through the portal vein- allow for detoxification before entering general circulation

Question 50

large intestine

Answer 50

1.5 meters, colon reabsorbs water, vitamins, salt contains bacteria ecoli - produces vitamin b and k

Question 51

caecum

Answer 51

pouch at the beginning, appendix attached humans cannot digest cellulose- caecum is nonfunctional

Question 52

rectum

Answer 52

stores feces, anal sphincters- voluntary control hemeroids, diarrhea, constipation