B3: The Digestive System Flashcards
What is a TISSUE?
A group of cells with a similar structure and function working together.
What are ORGANS?
Collections of tissues.
What tissues does the stomach contain and their function ? (6)
MUSCULAR tissue - to churn food/digestive juices together
GLANDULAR tissue - to produce digestive juices to break food down
EPITHELIAL tissue - covers inside/outside of the organ
What are ORGAN SYSTEMS ?
Grouops of organs that work together to perform a specific function .
What are glands and their function ?
Glands are organs that make one or more substances.
- they make/release digestive juices containing ENZYMES to break down food
CARBOHYDRATES - function/what they are made up of
FUNCTION : provide us with fuel that make all other reaction of life possible
MADE OF : units of sugar
- SIMPLE SUGARS - carbs that contain only one or two sugar units
- COMPLEX CARBS - carbs containing long chains of simple sugar units bonded together
LIPIDS - what they are/ function/ what they are made of
Lipids are fats and oils.
FUNCTION : efficient energy STORE in the body and important SOURCE of energy
MADE OF : 3 molecules of FATTY ACIDS and a molecule of GLYEROL
PROTEINS - function/what they are made of
FUNCTION : used for building up cells/tissues of the body as well as a basis of all your ENZYMES!
MADE OF : long chains of amino acids
TEST FOR : simple sugars, complex carbs, proteins, lipids
(BIBE)
How do you tell if the compound is present?
Glucose : BENEDICT’S TEST FOR SUGARS (blue-> brick red/brown )
Complex carbs : IODINE TEST FOR STARCH (yellow/red -> blue/black)
Proteins : BIURET TEST ( blue -> purple)
Lipids : ETHANOL TEST ( cloudy white layer)
What is a catalyst ?
A substance that increases the rate of a chemical reaction .
NOT USED UP IN A REACTION!
What are enzymes? How can they bind to specific substrate molecules?
- Large protein molecules
The long chains of amino acids are folded to produce a molecule with an active site. This active site has a unique shape so it can bind to a specific substrate .
What is metabolism ?
The sum of all the reactions in the cell or body .
Enzymes control metabolism .
How does temperature effect enzyme action ?
- after optimum temperature amino acids unravel and active site loses shape
- substrate cant fit in active site
- enzyme is DENATURED
How does pH effect enzyme action ?
change in pH affects forces between parts of protein that hold the protein/active site in shape
- the active site will change shape if pH changes
- enzyme cat be used as a catalyst anymore
CARBOHYDRATES - enzyme that catalyses break down/ where enzyme is produced / where enzyme acts / product after breaking down
ENZYME : carbohydrase
PRODUCED : salivary glands /pancreas/small intestine
ACTS IN: mouth/ small intestine
PRODUCT : simple sugars
PROTEINS - enzyme that catalyses break down/ where enzyme is produced / where enzyme acts / product after breaking down
ENZYME : Proteases
PRODUCED : stomach/ pancreas/small intestine
ACTS IN : stomach/small intestine
PRODUCT : amino acids
LIPIDS - enzyme that catalyses break down/ where enzyme is produced / where enzyme acts / product after breaking down
ENZYME : lipase
PRODUCED : pancreas/small intestine
ACTS IN : small intestine
PRODUCT: fatty acids /glycerol
What is digestion/what does it involve?
Involves break down of large insoluble substances into smaller soluble substances that can be absorbed into the blood across the wall of the small intestine.
What are digestive enzymes produced by ?
By specialised cells in glands and in the lining of digestive system
What conditions do stomach protease enzymes work best in ?
ACIDIC ( hence HCl in stomach)
What conditions do enzymes made in the pancreas.small intestine work best in ?
ALKALINE
What is BILE?
A fluid that is made/released in the LIVER, stored in the GALL BLADDER and released through the BILE DUCT.
functions of BILE?
- Neutralise acid added to food in stomach for alkaline conditions
- Emulsifies fats - breaks large drops of fats into smaller droplets
- increase SURFACE AREA of fats for lipase to act upon
- speeds up breakdown of fats
What causes coeliac disease?
The immune system mistakes substances found in gluten as a threat to the body so it attacked them
How is the surface area of the small intestine increased?
By Villi with a network of blood vessels
What are proteins used for/act as?
Enzymes
Antibodies
Hormones (like insulin)
Structural components of tissues (muscles/tendons)
describe a test to show whether a person’s urine contains GLUCOSE? signs of a positive result? (2)
add BENEDICT’S SOLUTION to urine/ BOIL
- positive if goes from BLUE -> BRICK RED
Why do ppl with coeliac’s have poor growth? (4)
- damaged villi REDUCE SA for absorbtion
- so fewer amino acids/glucose absorbed
- less glucose means less transfer of energy from respiration
- fewer amino acids available to build new proteins
