B2-Organisation & digestive system Flashcards
What makes up a TISSUE?
A group of similar cells makes up a TISSUE
What makes up an ORGAN?
A group of tissues makes up an ORGAN
What makes up an ORGAN SYSTEM?
A group of organs makes an ORGAN SYSTEM
Name some organ systems and organs included in them.
Circulatory: heart, veins, arteries Respiratory: Lungs, trachea, diaphragm
Digestive: Stomach, small intestines, mouth etc
Nervous: Brain, spinal chord
Skeletal: Bones Reproductive: Penis, testes, ovaries, vagina
Name some Tissues and their functions
Muscular - contracts to bring about movement
Glandular - contains secretory cells that can produce and release substances like enzymes or hormones
Epithelial - covers the outside of our bodies as well as internal organs
Food tests:
What do these nutrients need and show if the result is positive?
- Starch
- Fat
- Simple sugar
- Protein
Starch Testing reagent - Iodine solution NO HEAT is required Positive result shows blue-black
Fat Testing reagent - Ethanol NO HEAT is required Positive result shows - Oil drops form at surface
Simple Sugar Testing reagent - Benedict’s solution HEAT IS REQUIRED Positive result shows - Orange (brick-red)
Protein Testing reagent - Biuret A or B reagent NO HEAT is required Positive result shows - pale lilac
What is Digestion?
Digestion is the breakdown of large insoluble molecules into small soluble ones.
Name organs in the digestive system.
Mouth
Salivary glands
oesophagus
liver
stomach
gallbladder
pancreas
small intestine
large intestine
rectum
anus
What is the function of the MOUTH?
It’s the FIRST stage in MECHANICAL DIGESTION.
Food is broken up into smaller pieces and mixed with saliva.
Saliva contains ENZYMES and helps lubricate food so it can be SWALLOWED and DIGESTED.
What is the function of the Oesophagus?
A wave of muscular construction called PERISTALSIS moves food from mouth to stomach.
What is the function of the stomach?
Thick muscular walls which churns the food - further broken down. It secretes HCl (hydrochloric acid) which creates the correct pH for activating enzymes and kills any microbes we might have consumed.
What is the function of the Small Intestine?
Where the small soluble molecules get absorbed in the blood.
The walls of the small intestine are highly folded into villi . This gives a large surface area .
They have a good blood supply so short diffusion distances.
Muscular walls squeeze undigested food to the large intestine.
What is the function of the Large Intestine?
Where water and electrolytes are absorbed back into the body.
Formation of faeces
What is the function of the rectum?
Stores faeces
What are Enzymes?
Enzymes are biological catalysts - they speed up chemical reactions but do NOT get used up. They are made of PROTEIN. They catalyse different metabolic reactions: • build up large molecules i to smaller ones • break up large molecules •change one molecule into another
What shape do enzymes have?
Enzymes have a very specific shape.
The part of the enzyme to which the substrate binds is called the active site. (most important part of the enzyme).
The enzyme is the lock, and the substrate is the key.
What is the SUBSTRATE?
It’s the molecule (‘key’) that the enzyme (‘lock’) works on.
What is an ACTIVE SITE?
The specific part of the enzyme (lock) that the substrate (key) fits into.
What happens after the enzyme has finished working on the SUBSTRATE?
It leaves PRODUCTS these are products of the broken down substrate.
How do the enzyme and substrate fit together?
The enzyme and substrate fit together like a lock and a key.
enzyme is the lock and the substrate is the key
What do enzymes only work in and require?
Enzymes only work in specific conditions.
They need a specific temperature and pH.
What is the optimum temperature?
This optimal temperature is usually around human body temperature (37.5 oC) for the enzymes in human cells.
Above this temperature the enzyme structure begins to break down (denature) since at higher temperatures intra- and intermolecular bonds are broken as the enzyme molecules gain even more kinetic energy.
What does it mean if the enzyme has a low rate of reaction?
This means the particles do not have as much kinetic energy.
What happens when an enzyme becomes denatured (e.g. high body temperature)?
The enzyme has changed shape - the active site and substrate no longer fit together. This is IRREVERSIBLE.
What happens when the enzyme Amylase is added to Starch?
Starch turns into Simple Sugars (glucose).
What does ‘ase’ mean on the end of a word.
It means it’s an enzyme. E.g. Protease