12.Digestive system and enzymes Flashcards
define digestion
the breakdown of large insoluble molecules into small soluble molecules by chemical and physical means
function of mouth in digestion
1.teeth physically (mechanically) breakdown food into smaller pieces
2.saliva containing amylase chemically breaks down starch
function of salivary glands in digestion
-makes saliva which is required for lubrication to swallow food
-salvia contains salivary amylase
-amylase breaks down starch into maltose
-only carbohydrates get broken down in the mouth
function of oesophagus in digestion
-connects mouth to stomach
-moves food by peristalsis- muscle contractions
function of stomach in digestion
-muscular bags churn food- PHYSICAL breakdown
-stomach makes pepsin which breaks down polypeptides into dipeptides
-stomach makes HCl
-this kills pathogens and provides optimum pH for pepsin to function
-only proteins start to be broken down in stomach
function of small intestine-duodenum in digestion
-1st part of small intestine
-enzymes from pancreas are released into duodenum that breaks down proteins, lipids and carbohydrates
-bile is also added at this point
-ph 7
-digestion is completed here
function of liver in digestion
-no food enters liver
-liver makes bile
-bile PHYSICALLY breaks down large lipid molecules into smaller droplets
function of pancreas in digestion
-no food enters pancreas
-the pancreas makes enzymes that breaks down lipids, proteins and carbohydrates
-enzymes pass from pancreas to duodenum down pancreatic duct
function of small intenstine-ileum for digestion
-last part of small intestine
-where the final products of digestion are absorbed into the bloodstream
-villi and microvilli increase SA of small intensive for absorption
function of large intestine for digestion
-absorbs water by osmosis
-consists of colon and rectum
rectum function
stores faeces for defaecation
anus function
faeces pass through anus -egestion
what is activation energy
the energy needed to start a reaction
anabolic/___
+Eg
endergonic
build up
energy required
eg condensation polymerisation, protein synthesis and photosynthesis
catabolic/__
+Eg
exergonic
breakdown
energy releasing
eg respiration, hydrolysis, glycolysis
what is an enzyme
a protein biological catalyst that speeds up chemical reactions by lowering activation energy
labels for 3 part enzyme diagram
-enzyme (E)
-substrate
-active site (specific and complementary in terms of shape and charge to the substrate)
-enzyme substrate complex
-products
-3 arrows
what colour is phenolphthalein in acidic solutions
colourless
what colour is solution (with phenolphthalein) when lipids break down
colourless because fatty ACIDS are produced, lowering pH
enzyme at low temperature (below optimum)
EXPLAIN
-because enzyme is inactive at low temperature
-then there will be less kinetic energy and decreased frequency of collisions and decreased frequency of SUCCESSFUL collisions leading to less enzyme substrate complexes forming
-therefore there will be less products and a slower rate of reaction
enzyme at optimum temperature
EXPLAIN
-because the enzyme is functioning at its optimum
-then there will be higher frequency of collisions and higher frequency of SUCCESSFUL collisions leading to the most enzyme substrate complexes being formed
-therefore the most products will be found and at a faster rate of reaction
enzymes at very high temperatures
EXPLAIN
-because the enzyme is denatured
-then the 3d structure of the active site of the enzyme is no longer complementary and specific (in terms of shape and charge) to the substrate meaning less enzyme substrate complexes will be formed
-therefore the least amounts of products will be produced at a lower rate of reaction
enzymes in low or high pH
EXPLAIN
-because the enzyme is denatured at low/high pH
-then the 3d structure of the active site of the enzyme is no longer complementary and specific (in terms of shape and charge) to the substrate, meaning less enzyme substrate complexes will be formed
-therefore the least amounts of products will be produced at a lower rate of reaction
enzymes in optimal pH
EXPLAIN
-because the enzyme is functioning at its optimum
-then there will be higher frequency of collisions and higher frequency of SUCCESSFUL collisions leading to the most enzyme substrate complexes being formed
-therefore the most products will be found and at a faster rate of reaction
how is hydrogen peroxide broken down
-catalase catalyses process of breaking down the potentially harmful substance hydrogen peroxide
-products are oxygen and water
define absorption
absorption is the movement of digested food molecules into the blood or lymph
outline the small intestine adaptations for absorption
rich blood supply-maintains diffusion gradient
thin walls-short distance for molecules to diffuse
moist-molecules diffuse in solution
villi & microvilli-increase SA for absorption
name 5 molecules that need to be absorbed
glucose, fructose, amino acids, minerals, water, glycerol, fatty acids, ions
function of capillaries
-absorbs monosaccharides, amino acids, vitamins and minerals
-done by diffusion initially
-once equilibrium is reached, active transport maximises absorption by moving solute against the concentration gradient
function of lacteal
-absorbs fatty acids and glycerol
-part of lymphatic system
function of epithelial cells
-contain protein channels for facilitated diffusion and protein pumps for active transport
-contain many mitochondrion to provide ATP for active uptake
-molecules enter initially via facilitated diffusion, once equilibrium is reached active transport is required to maximise absorption of Molecules
define assimilation
assimilation is the movement of digested food molecules into cells of the body where they are used or become part of the cell
define excretion
the process of eliminating or expelling waste matter
what is urine made up of
96% water
4-7%:urea, uric acid, salts
organs in excretory system
2x kidneys
ureter
bladder
urethra
name four parts of nephron
Bowmans capsule
proximal convoluted tubule
loop of Henle
distal convoluted tubule
Bowmans capsule function
FILTERS THE BLOOD
water and small molecules can pass into proximal convoluted tubule. Large proteins and blood cells stay behind
Proximal convoluted tubule function
REABSORPTION OF IONS
glucose, specific ions, and amino acids are reabsorbed into capillaries by active transport
Loop of Henle function
REABSORPTION OF WATER
the ascending limb actively pumps ions out of the tubule. This makes the tissue surrounding the descending limb highly concentrated, so water exits
distal convoluted tubule function
SELECTIVE REABSORPTION
more active transport of ions out, so that water follows based on requirements and water needs
what is the endocrine system
network of glands in animals that secrete hormones into the blood to travel to nearby/ distant cells
what is a hormone
chemical signalling molecule secreted directly into the bloodstream by a gland which travels to a target organ or cell
types of hormones +egs
Lipid (steroid)- testosterone and estrogen
Protein-ADH
Amino acid-adrenalin
function of pituitary gland
an organ of the endocrine system that releases hormones that regulate growth and reproduction
function of pancreas
an organ of the endocrine system that releases hormones that regulate BGL
how does urine leave body
ureter, bladder, urethra
