12.Digestive system and enzymes

Question 1

define digestion

Answer 1

the breakdown of large insoluble molecules into small soluble molecules by chemical and physical means

Question 2

function of mouth in digestion

Answer 2

1.teeth physically (mechanically) breakdown food into smaller pieces
2.saliva containing amylase chemically breaks down starch

Question 3

function of salivary glands in digestion

Answer 3

-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

Question 4

function of oesophagus in digestion

Answer 4

-connects mouth to stomach
-moves food by peristalsis- muscle contractions

Question 5

function of stomach in digestion

Answer 5

-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

Question 6

function of small intestine-duodenum in digestion

Answer 6

-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

Question 7

function of liver in digestion

Answer 7

-no food enters liver
-liver makes bile
-bile PHYSICALLY breaks down large lipid molecules into smaller droplets

Question 8

function of pancreas in digestion

Answer 8

-no food enters pancreas
-the pancreas makes enzymes that breaks down lipids, proteins and carbohydrates
-enzymes pass from pancreas to duodenum down pancreatic duct

Question 9

function of small intenstine-ileum for digestion

Answer 9

-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

Question 10

function of large intestine for digestion

Answer 10

-absorbs water by osmosis
-consists of colon and rectum

Question 11

rectum function

Answer 11

stores faeces for defaecation

Question 12

anus function

Answer 12

faeces pass through anus -egestion

Question 13

what is activation energy

Answer 13

the energy needed to start a reaction

Question 14

anabolic/___
+Eg

Answer 14

endergonic
build up
energy required
eg condensation polymerisation, protein synthesis and photosynthesis

Question 15

catabolic/__
+Eg

Answer 15

exergonic
breakdown
energy releasing
eg respiration, hydrolysis, glycolysis

Question 16

what is an enzyme

Answer 16

a protein biological catalyst that speeds up chemical reactions by lowering activation energy

Question 17

labels for 3 part enzyme diagram

Answer 17

-enzyme (E)
-substrate
-active site (specific and complementary in terms of shape and charge to the substrate)
-enzyme substrate complex
-products
-3 arrows

Question 18

what colour is phenolphthalein in acidic solutions

Answer 18

colourless

Question 19

what colour is solution (with phenolphthalein) when lipids break down

Answer 19

colourless because fatty ACIDS are produced, lowering pH

Question 20

enzyme at low temperature (below optimum)
EXPLAIN

Answer 20

-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

Question 21

enzyme at optimum temperature
EXPLAIN

Answer 21

-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

Question 22

enzymes at very high temperatures
EXPLAIN

Answer 22

-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

Question 23

enzymes in low or high pH
EXPLAIN

Answer 23

-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

Question 24

enzymes in optimal pH
EXPLAIN

Answer 24

-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

Question 25

how is hydrogen peroxide broken down

Answer 25

-catalase catalyses process of breaking down the potentially harmful substance hydrogen peroxide -products are oxygen and water

Question 26

define absorption

Answer 26

absorption is the movement of digested food molecules into the blood or lymph

Question 27

outline the small intestine adaptations for absorption

Answer 27

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

Question 28

name 5 molecules that need to be absorbed

Answer 28

glucose, fructose, amino acids, minerals, water, glycerol, fatty acids, ions

Question 29

function of capillaries

Answer 29

-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

Question 30

function of lacteal

Answer 30

-absorbs fatty acids and glycerol -part of lymphatic system

Question 31

function of epithelial cells

Answer 31

-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

Question 32

define assimilation

Answer 32

assimilation is the movement of digested food molecules into cells of the body where they are used or become part of the cell

Question 33

define excretion

Answer 33

the process of eliminating or expelling waste matter

Question 34

what is urine made up of

Answer 34

96% water 4-7%:urea, uric acid, salts

Question 35

organs in excretory system

Answer 35

2x kidneys ureter bladder urethra

Question 36

name four parts of nephron

Answer 36

Bowmans capsule proximal convoluted tubule loop of Henle distal convoluted tubule

Question 37

Bowmans capsule function

Answer 37

FILTERS THE BLOOD water and small molecules can pass into proximal convoluted tubule. Large proteins and blood cells stay behind

Question 38

Proximal convoluted tubule function

Answer 38

REABSORPTION OF IONS glucose, specific ions, and amino acids are reabsorbed into capillaries by active transport

Question 39

Loop of Henle function

Answer 39

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

Question 40

distal convoluted tubule function

Answer 40

SELECTIVE REABSORPTION more active transport of ions out, so that water follows based on requirements and water needs

Question 41

what is the endocrine system

Answer 41

network of glands in animals that secrete hormones into the blood to travel to nearby/ distant cells

Question 42

what is a hormone

Answer 42

chemical signalling molecule secreted directly into the bloodstream by a gland which travels to a target organ or cell

Question 43

types of hormones +egs

Answer 43

Lipid (steroid)- testosterone and estrogen Protein-ADH Amino acid-adrenalin

Question 44

function of pituitary gland

Answer 44

an organ of the endocrine system that releases hormones that regulate growth and reproduction

Question 45

function of pancreas

Answer 45

an organ of the endocrine system that releases hormones that regulate BGL

Question 46

how does urine leave body

Answer 46

ureter, bladder, urethra