TOPIC B2 ORGANISATION Flashcards
what are organ systems
organisms working together to perform a specific function
what are similar cells organised into
tissues
define the term tissue
-a group of similar cells that work together to carry out a particular function
-it includes more than 1 type of cell
state 3 tissues in mammals
-muscular tissue, contracts to move whatever its attatched to
-glandular tissue, which makes and secretes chemicals like enzymes and hormones
-**epithethal **tissue. which covers some parts of the body e.g inside the gut
define the term organ
a group of different tissues working together to perform cetrain functions
state what the stomach is an organ made up of and why it needs these
The stomach has three roles:
-To mechanically digest food through the churning of food
-To produce the enzyme protease
-To produce hydrochloric acid (stomach acid)
what is an organ system
a group of organs working together to perform a particular function
state 5 organs in the digestive system
-Mouth
-Oesophagus
-Stomach
-Small intestine (duodenum and ileum)
-Large intestine
-Rectum
why does the digestive system need glands
to produce digestive juices
why does the digestive system need the stomach
to digest food
why does the digestive system need the liver
to produce bile
why does the digestive system need small intestine
to absorb soluble food molecules
why does the digestive system need large intestine
to absorb water from undigested food, leaving faeces
state 1way to increase a chemical reaction
by raising temperatures
what is a catalyst
a substance which increases the speed of a reaction, without being changed or used up in the reaction
what are enzymes made up of
-large proteins
-chains of amino acids
why do enzymes only catalyse one reaction
state 2things enzymes need for a reaction
-right temperature (an optimum one)
-right pH (neutral, 7)
state what must of happened for an enzyme to become denatured
-a high temperature increases the rate at first
-if it gets too hot, some bonds holding the enzymes together break
-this changes the enzymes active site so the subsrate will not fit anymore
what are enzymes used in digestion produced and released into
-produced by cells
-released into the gut to mix with food
The lock and key model
- enzymes and substrates move about randomly in solution
- when an enzyme and its complementary substrate randomly collide, with the substrate fitting into the active site of the enzyme, an enzyme substrate complex form
- product form from subsrate are released from the active site. The enzyme’s unchanged and will go on
The effect of temperature on enzyme activity
-enzymes work fastest at optimum temperature
-heating to high temps will start to break the bonds that hold enzymes together, it will start to distort and lose its shape, reducing effectiveness of substrates
-eventually the enzyme is denatured
The effect of pH on enzyme denaturation
-optimum is 7
-if pH is too high/low the bonds that hold the amino acid chain are destroyed
-changing the shape of the active site, so substrate can no longer fit, reducing rates of activity
what molecules need to be broken down by digestive enzymes
-starch, amino acids
-proteins, glycerol
-fats, fatty acids
smaller soluble molecules that pass easily through the walls