B3 - Organisation and the digestive system Flashcards
What are cells
the basic building blocks of living organisms
What is cell differentiation
becoming specialised to carry out particular jobs
What are tissues
groups of cells with similar structures and functions
What does muscular tissue do
contract to bring about movement
What does glandular tissue do
contains secretory cells that can produce and release substances such as enzymes and hormones
What does epithelial tissue do
cover the outside of the body as well as internal organs
What are organs
groups of tissues that work together to perform a specific function
What types of tissue are in the stomach
- what are their purposes
- muscular tissue churns food and digestive juices together
- glandular tissue produces the digestive juices
- epithelial tissue covers the inside and outside of the organ
What are the two types of tissue in the pancreas
- what is the pancreas’ two main jobs
ones that make hormones and enzymes
- makes hormones to control blood sugar
- makes enzymes that digest food
What is an organ system
a group of organs that work together to perform specific functions
What are some organ systems in the human body
- digestive system
- endocrine system
- circulatory system
- gas exchange system
What are some ways organisms can be adapted to perform their job well
- rich blood flow
- large SA
- short diffusion distances
What are the levels of organisation in an organism
cells -> tissues -> organs -> organ systems -> organisms
What is the function of the digestive system
to break down food into smaller, soluble molecules that can be absorbed and used by cells
What organs and glands are contained in the digestive system
- mouth (salivary gland, teeth)
- gullet
- stomach
- liver
- pancreas
- gall bladder
- duodenum
- bile duct
- small intestine
- large intestine
- appendix
- rectum
- anus
What do glands such as the pancreas and salivary glands do in the digestive system
produce digestive juices containing enzymes to break down food
Where in the digestive system does most digestion take place
stomach and small intestine
Where is soluble food molecules absorbed into blood
small intestine
how is the small intestine adapted to have fast diffusion and active transport
lots of villi for greater SA
- good blood supply
- short diffusion distances
what happens in the large intestine
- what happens to left-over material
water is absorbed from undigested food into blood
- forms faeces
what is the function of the liver in the digestive system
produces bile which helps in the digestion of lipids
What are the three main compounds that make up the structure of a cell
carbohydrates, lipids, proteins
What do carbohydrates provide us with
fuel that makes reactions possible
What are the two types of carbohydrates
- what are some examples
simple sugars contain only one sugar unit
- glucose, sucrose
complex sugars are made of long chains of units (polymers)
- starch and cellulose
What happens to carbohydrates when they are eaten
they are normally broken down into glucose, used in cellular respiration to provide energy for metabolic reactions
What are lipids
fats and oils, the most efficient energy store inthe body
What are some properties of lipids
- made from carbon, hydrogen and oxygen
- insoluble in water
What are lipids made of
3 molecules of varying fatty acids to a molecule of constant glycerol
What are proteins used for in the body
building up cells and tissues, and the basis of enzymes
What are proteins made from
- carbon
- oxygen
- nitrogen
- hydrogen
What are proteins made from
- how many are there
amino acids chained together
- around 20
each combination gives a different protein
why does the shape of protein structures get lost easily
- what is this called
bonds are sensitive to pH and temperature
- denatured
What are some functions of proteins in the body
- structural components e.g. tendons and muscles
- hormones
- antibodies
- enzymes
What is the chemical test for starch
add iodine
- yellow, red -> blue, black
What is the chemical test for sugars
add benedicts solution and heat
- blue -> brick red
What is the chemical test for proteins
- What is the danger of this experiment
add biuret reagent
- blue -> purple
- biuret reagent is corrosive
What is the chemical test for lipids
- what is the danger with this
add ethanol
- cloudy white layer if lipids are present
- ethanol is highly flammable
what are enzymes
proteins that act as biological catalysts
how are enzymes shaped
chains of amino acids are folded to produce molecules with a unique shape active site
What is the lock and key model
substrate fits active site, like a lock and key, at the active site
- substrate splits and leaves the active site
- enzyme is reused
What are some actions controlled by enzymes
- give examples of each
- making larger molecules e.g. C, H and O -> glucose, glucose and nitrate ions to amino acids
- changing molecules e.g. glucose to fructose
- breaking down large molecules e.g. glucose in respiration
What are some factors that affect biological reactions
concentration, temperature, surface area
how does temperature affect enzyme action
the higher the temperature, the faster the reaction until the enzyme denatures
What temperature do most human enzymes work best at
37 degrees
Why does pH affect enzyme action
pH affects forces that hold the amino acid chains in place
What is the difference between digestive enzymes and most other bodily enzymes
digestive enzymes work outside of cells
Where are digestive enzymes produced
in the pancreas, salivary glands, lining of the digestive system
Why does the digestive system squeeze food
because it is hollow and muscular
- it breaks the food into smaller particles with large surface areas for enzymes to work on
Why does the digestive system have varying pH levels
so that different enzymes can work as efficiently as possible
What enzyme breaks down carbohydrates
- where is it produced
- where does digestion take place
- what is made from this digestion
amylase / carbohydrase
- salivary glands and pancreas
- mouth and small intestine
- small sugars
What enzyme breaks down proteins
- where is it produced
- where does digestion take place
- what is made from this digestion
protease
- stomach, pancreas and small intestine
- stomach and small intestine
- amino acids
What enzyme breaks down lipids
- where is it produced
- where does digestion take place
- what is made from this digestion
lipase
- pancreas and small intestine
- small intestine
- fatty acids and glycerol
how is digestion made efficient
- changing pH
- ## altering surface area
What is the pH of the stomach
- How
- How does it not burn the stomach
very low, acidic
- HCl is produced
- a thick layer of mucus is produced
What happens when someone has a stomach ulcer
the mucus layer is lost and acid attacks the stomach lining
How is the small intestine adapted for digestion
- how is acidic substance from stomach neutralised
- alkaline pH for optimum functionality
- bile
What does the bile duct do
squirt bile on the acidic mixture from the stomach
What are the two functions of bile
- neutralises acidic solution from stomach
- emulsifies fats
Why do fats need to be emulsified
it sticks together and therefore has a low surface area for lipase to act on, therefore digestion would be very slow
What do gall stones do
block the gall bladder and bile ducts, not allowing bile to be released on to food and reducing the efficiency of digestion