B3 organisation and the digestive system Flashcards
tissue definition
group of cells with similar structure and function
organ definition
collection of different tissues performing a common function
organ system definition
groups of organs that perform specific functions in the body
role of digestive system in mammals
digest and absorb food
testing for sugar
Benedict’s solution
hot water bath
blue -> brick red
starch test
iodine SOLUTION
yellow/orange/red to blue black
lipid test
emulsion test
clear to cloudy/ milky white
protein test
biuret reagent
blue to purple
what do catalysts do
increase rate of chemical reactions without changing chemically themselves
enzyme action
biological catalysts
catalyse specific reactions in living organisms
(due to shape of their active site)
lock and key theory
active site of enzyme must be complementary to the substrate
what is metabolism
sum of all the reactions in a cell or body
factors of enzyme activity
temperature and pH
effect of high temp on active site
active site denatures, changing the shape so it no longer matches the substrate molecule (canot bind)
effect of pH on active site
can affect shape of active site and make it work efficiently or not at all
what is digestion
breakdown large insoluble molecules ->soluble substances
absorbed into the blood across the wall of small intestine
where are digestive enzymes produced
by specialised cells in glands in the lining of the digestive system
breakdown of carbs
made from carbon, hydrogen and oxygen
catalyst- amylase
into simple sugars
breakdown of proteins
protease
into amino acids
breakdown of lipids
lipase
into fatty acids and glycerol
stomach pH
acidic conditions
hydrochloric acid produced
maintains low pH
small intestine pH
enzymes made in pancreas work best in alkaline conditions
higher pH
bile
produced by liver
stored in gall bladder
released through bile duct
neutralises acid and emulsifies fats
food pathway digestive system
mouth esophagus stomach small then large intestine rectum anus
what is an enzyme
chemical which catalyses reactions in living organisms
amylase production
salivary glands
pancreas
small intestine
protease production
stomach (pepsin)
pancreas
small itestine
lipase production
pancreas
small intestine
updated lock and key theory
induced fit model
in order for an enzyme to catalyse a reaction, the enzymes active site changes shape slightly as it binds to the substrate
balanced diet
includes appropriate proportions of all the different biological molecules
including carbohydrates, proteins, lipids, vitamins, minerals, dietary fibre, and water
factors affecting calorie intake
activity level
age
height
gender
pregnancy
biological molecules
bm are molecules found in living organisms, produced by cells
nutrients
substances needed for growth, repair and metabolism
