B.3cell organisation and role of enzymes Flashcards
What is a tissue?
A group of cells with similar structure and function
What is an organ?
An aggregation of tissues that perform a specific function
What is an organ system?
Different organs working together
state the different tissues that the stomach contains
-muscular tissue, to churn the food and digestive juices of the stomach together
-glandular tissue, produce digestive juices that break down
-epithelial tissue, covers the inside and outside of the organ
whats the function of a liver
producing bile
function of a stomach
break down large insoluble molecules** into smaller **soluble molecules and absorption
function of a small intestine
break down large insoluble molecules into smaller soluble molecules and absorption
function of large intestine
absorbs water from undigested food
explain the difference between organs and organ systems
an organ is a collection of tissues whereas
-organ system is a group of organs that work together
whats the digestive system
a group of organs that work together to digest and absorb food
-a muscular tube that squeezes food through it starts at one end with your mouth and finishes with your anus
where are the main places where food is digested
stomach
small intestine
what make up the structure of a cell and what are they made up of
carbohydrates, lipids and protein
often made up by smaller molecules joined together as part of the cell metabolism
carbohydrates provide us…
with fuel, energy
contain
-carbon
-hydrogen
-oxygen
an example of complex carbohydrates
starch
cellulose
-made up of long chains of simple sugar units bonded together
glucose + sucrose
simple sugars
lipids are made up of…
3 molecules of fatty acids
what are lipids
fats and oils
what are proteins
used for building up the cells and tissues of the body
what mass of the body is protein
15-16%
how to test for starch
-place a small amount of food on a spotting tile
-add a few drops of iodine
-if it changes from yellow-red to blue-black starch is oresent
how to test for sugars
-place small amounts of food into a test tube
-add drops of Benedict solution
-heat test tube in water bath
-if it changes from blue to brick red sugar is present
how to test for protein
-place small amount of food into test tube
-add 1cm of biuret solution
-if colour goes from pale blue to purple protein is present
how to test for fats
place a small amount of food into a test tube
-add drops of ethanol to the solution
-shake the test tube and leave for 1minute
-pour ethanol into test tube of water
-a cloudly white layer will appear if present
define a catalyst
a substance that speeds up the rate of another reaction but isn’t used up
define a enzyme
biological catalysts, usually proteins
define active site of an enzyme
the site on an enzyme where reactants bind
how do enzymes act to speed up reactions
-increasing temp
but if it gets too hot the the bonds holding it together will break
-this changes the shape of the enzymes active site, then the substrate won’t fit anymore
-enzyme is DENATURED
3reactions to speed up enzymes
-building large molecules from lots of smaller ones
-changing one molecule into another
-breaking down large molecules into smaller ones
