Biological Molecules Flashcards
glucose
small simple sugar molecule (what carbs are made of)
starch
long molecule consisting of numerous glucose molecules joined together in long strings, some types have occasional branches, type of carb
amino acids
small single units, 20 different kinds (what proteins are made of)
proteins
long chains of amino acids, the sequence of amino acids is different for each protein with a unique 3d shape
glycerol
simple, small molecule (what lipids are made out of)
fatty acid
a simple long molecule (what lipids are made of)
lipids
glycerol and fatty acid molecule(s) attached
what are enzymes made of?
proteins
biological catalyst
- speeds up reactions by lowering the activation energy
- not used up or changed during the reaction
function of enzymes, example
break large molecules into small ones, e.g. protease: protein -> amino acids; lipase: lipids -> fatty acids and glycogen; carbohydrase: carbs -> sugars
appearance of enzymes
specific and will only on substrates whose shape is complementary to the shape of the enzyme’s active site
lock and key model
- substrate binds to the active area of the enzyme
- forms enzyme substrate complex
- enzyme releases the products
activation energy and what do enzymes change about it
minimum energy required without enzymes to overcome the energy barrier to get a reaction started; enzymes can lower the activation energy so it’s possibkle for reactions to occur at lower temperatures
types of enzymes
extra-cellular (work outside the cell) and intracellular (work inside the cell)
factors that affect the rate of enzyme-catalysed reactions
substrate concentration, enzyme concentration, temperature, pH
optimum temperature/ pH
where the enzyme works best/ fastest
what happens to enzymes when there is an increase in temperature before the optimum temperature
increase in temperature and therefore kinetic energy of the enzyme and substrate particles -> more likely to collide -> increasing enzyme activity
what happens to enzymes when there is an increase in temperature after the optimum temperature
the increase in temp/ kinetic energy causes the bonds of the enzyme to break, denaturing the enzyme -> decreases the rate of reaction/ enzyme activity until it stops altogether
what happens to the enzymes when there is an increase/ decrease of pH that are not of the optimum pH? (too acidic or alkaline)
the rate of enzyme action decreases, as it disrupts the bonds that hold the enzyme together, making the enzyme become denatured
what does denaturing an enzyme mean?
the substrate can no longer bind to the active site as their shapes are no longer complementary
5 parts of the digestive system
ingestion, digestion, absorption, assimilation, egestion
ingestion
taking food into body through mouth
digestion
chemical and mechanical breakdown of food that converts large insoluble molecules into small soluble molecules that can be absorbed into the blood
absorption
the movement of small soluble molecules through the wall of the small intestine into the blood stream
assimilation
the use of digested and absorbed soluble food substances to make new products in cells (after being regulated by the liver)
egestion
the removal of feces (food waste) by the body
egestion vs excretion
excretion: waste products of metabolic reactions from cells
egestion: waste products which have been passed through the gut without entering cells
where food goes
- mouth, consisting of teeth, salivary glands and tongue
- esophagus
- stomach
- small intestine, consisting of duodenum and ileum
- large intestine, consisting of appendix, colon and rectum
what types of muscle do the walls of the gut consist of?
circular muscular rings and a longitudinal layer of muscle that wrap around the rings
how do the contractions of circular and longitudinal muscles look like?
circular: contracts inwards
longitudinal: contracts outwards
peristalsis
waves of muscle contraction move food along the gut
behind the bolus (food): circular muscles contract, longitudinal muscles relax
in front of the bolus: circular muscles relax, longitudinal muscles contract
where does peristalsis occur?
the gut (esophagus, stomach, small intestine, large intestine)
benefit of peristalsis
avoids dependence on gravity to move food, e.g. food can be digested lying down
where does bile travel?
synthesized in the liver, stored in the gall bladder, secreted into the duodenum via the bile duct
functions of bile
- it is alkaline, neutralizing the acidic chyme which enters the duodenum from the stomach, providing the optimum pH for the enzymes in the duodenum
- emulsifies lipids (breaks large fat globule into small fat droplets), providing a larger surface area for the lipase enzyme to act on so that lipids can be broken down more efficiently into fatty acids and glycerol
saliva: where it’s made, where it acts, enzyme(s), optimum pH, substrate, products
salivary glands (mouth); mouth; salivary amylase; 7; starch; maltose (STARCH)
gastric juice: where it’s made, where it acts, enzyme(s), optimum pH, substrate, products
wall of stomach; stomach; pepsin; 2; protein; amino acids (PROTEIN)
bile: : where it’s made, where it acts, substrate, products
liver; duodenum; lipids (large droplets); lipids (small droplets) (LIPIDS)
pancreatic juice: where it’s made, where it acts, enzyme(s), optimum pH, substrate, products
pancreas; duodenum; pancreatic amylase, protease, lipase; 7; starch protein, lipids; maltose, amino acids, fatty acids and glycerol (STARCH PROTEIN LIPIDS)
enzymes inside cells forming wall of ileum: where it’s made, where it acts, enzyme(s), optimum pH, substrate, products
ileum; ileum; maltase; 7; maltose; glucose (MALTOSE)
digestive juices
saliva, gastric juice, pancreatic juice, enzymes inside cells forming wall of ileum
bile isn’t one but it aids digestion
enzymes that digest starch & its product
amylase (e.g. salivary amylase or pancreatic amylase); maltose
enzymes that digest protein & its product
pepsin/ protease; amino acids
enzymes that digest lipids & its product
lipase; fatty acids and glycerol
enzymes that digest maltose & its product
maltase; glucose
biuret test
test for protein
colour change for positive result: blue to purple
iodine test
test for starch
colour change for positive result: brown to blue-black
benedict’s solution
test for glucose
warm solution at 80oc
colour change for positive result: blue to brick-red
ethanol and water
test for lipid
colour change for positive result: clear to cloudy
absorption in the ileum
- after digestion, all the large molecules will have been broken down into small soluble molecules
- these small molecules are absorbed into the blood stream in the ileum by diffusion and active transport
- small molecules move into the capillaries in the ileum
- the blood flows through the capillaries and eventually into the hepatic portal vein
- the vein takes the blood to the liver so that the food molecules in the blood can be regulated
villus structure
outer layer: epithelial cells with microvilli on them
core: capillary network (absorbs amino acids and glucose), lacteal (part of the lymphatic system that absorbs fats)
function of folded shape of villus
increases the surface area for increased diffusion
microvilli
increases the surface area for increased diffusion
wall is one cell thick
short diffusion pathway
good blood supply
moves nutrients away from the small intestine to maintain a steep concentration gradient
lacteal
absorbs the products from the digestion of fats
muscle fibers around each villus
contract to keep the villi moving, keeping the villi in constant contact with the contents of the ileum
monosaccharides, disaccharides, polysacharides of carbs
mono: glucose
dis: maltose
poly: starch/ glycogen/ cellulose
experiment for testing enzyme activity
conduct the iodine test at different temperatures and see how long it takes for the solution to turn blue-black to brown as the enzymes break the starch down
carbohydrates: example, function, deficiency disorder
pasta, source of energy
proteins: example, function, deficiency disorder
meat; growth and repair, helps form enzymes; kwashiorkor’s disease
lipids: example, function
butter; helps for cell membranes, long-term energy storage
vitamin a: example, function
carrot; helps vision in low light
vitamin c: example, function, deficiency disorder
fresh fruit; helping to protect cells and keeping them healthy; scurvy
vitamin d: example, function, deficiency disorder
fish liver oils; helps bones grow by absorbing calcium; rickets/osteoporosis
calcium: example, function, deficiency disorder
dairy products; making teeth and bones; osteoporosis
iron: example, function, deficiency disorder
red meat/ spinach; needed to make haemoglobin for red blood cells; anaemia
fibre: example, function
vegetables; provides something for the muscles of the gut to push against and avoids constipation
