B3-organisation and the digestive system Flashcards
what is the pathway of digestion
mouth–>osophegus–>stomach–>pancreas, liver, gall bladder–>small intestine–>large intestine–> rectum –> anus
what is digestion
Digestion = the breakdown of large, insoluble molecules, to smaller soluble molecules
why must nutrients be soluble
Nutrients must be soluble so that they can dissolve into our blood plasma and be transported to the cells where they are needed
what do glands produce
Glands like pancreas and salivary glands release enzymes to break down food
what absorbs nutrients
Nutrients are absorbed into the blood from the small intestine
what absorbs water
Water is absorbed from the large intestine - once all the water has been absorbed into the blood, what’s left is faeces
how does food move in the intestines
Food moves through the intestines by the muscles squeezing –> peristalsis
what are our main food groups
Our main food groups are carbohydrates, proteins and lipids
what are polymers
These are all polymers - they are made up of smaller molecules to form one big molecule
what can our main food groups be broken down into
carbohydrates–> glucose
protein–> amino acids
lipids–>glycerol and fatty acids
what is glucose in terms of molecules
Glucose is a single sugar molecule
what are complex sugars and some examples
Complex carbohydrates like starch, cellulose are made up of simple sugar units bonded together
what are lipids important in
Lipids are important in your cell membranes, hormones and nerve cells
what are lipids
Lipids are fats and oils
why cant lipids dissolve in water
All lipids are insoluble in water
why are proteins important
15-20% of your body is protein. It is used to build your muscles, and enzymes, hormones, antibodies, antigens are all proteins
what are the appearance of protein and why are these shapes important
The long chains of amino acids are folded up into specific 3D shapes –> the shapes of proteins are very important because they allow them to carry out their function as best as possible
in terms of protein enzymes; what are bonds, what are they sensitive to and what happens when they are broken
Once folded, proteins are kept in that specific shape by bonds
These bonds are very sensitive to temperature and pH
If these bonds are broken, the proteins become ‘denatured’ and lose their shape
whats the definition of enzyme
Enzyme = a biological catalyst - it increases the rate of reaction (speeds up) of chemical reactions in the body
what does catalyst mean
Catalysts = something that speeds up a chemical reaction without being used up - they can be used over and over again
why are enzymes special
Enzymes have a SPECIFIC shape, that allows them to bind to only ONE substrate
what are enzymes
Enzymes’ are large protein molecules and their shape is really important to their function
what is the lock and the key in the lock and key model
FUN FACT: Enzymes can join together small molecules as well as break large ones up
FUN FACT: Enzymes can join together small molecules as well as break large ones up
What do enzymes control
Enzymes control metabolism
what does metabolism mean
Metabolism = the sum of all the reactions in a cell or in the body
what are some reactions that enzymes catalyse
Some reactions that enzymes catalyse are:
1)building large molecules from many smaller ones - lipids, starch, glycogen, cellulose and proteins
2)breaking larger molecules down into many smaller ones - excess amino acids to urea
Draw and explain the temperature graph for enzymes
Search up and mark - slow start NOT starting at zero, gradually increasing, and after the optimal temperature, rapid decrease, y-axis is always rate of reaction
what is the normal temperature for humans
37°C
describe and explain the enzymes graph
Initially, increasing temperature increases rate of reaction as the particles move with more energy at a higher speed, so there are more successful enzyme-substrate collisions in a given time
Once you pass the optimum temperature the enzyme denatures. So, the active site loses its shape, so it will no longer be complementary to the substrate, so they can no longer bind, so the rate of reaction decreases
Draw the pH graph for enzymes
Search up and mark - symmetrical graph, doesnt start at 0, y-axis=rate of reaction, x-axis=p
Search up and mark - symmetrical graph, doesnt start at 0, y-axis=rate of reaction, x-axis=pH
describe and explain the ph graph for rate of reaction on enzymes
Initially increasing the pH, the rate of reaction increases as it is getting closer to the optimal pH. Past the optimal pH, the rate of reaction decreases, as the deviation in pH disrupts the bonds holding the enzyme’s shape, causing it to denature. So, the active site loses its shape, so it will no longer be complementary to the substrate, so they can no longer bind, so the rate of reaction decreases
what are extremophiles
Extremophiles = organisms that live in extreme conditions (very high/very low temperatures, very dry)
Many are prokaryotes - enzymes in these have chemical adaptations that allow them to function in extremes of saltiness, high temp, or the cold
where are the different types of enzymes found
Amylase (enzyme for starch) in the mouth and small intestine (produced in pancreas) –> slight alkaline
Pepsinogen (protease) in the stomach –> v low pH acidic (ph-2?)
what are the enzymes broken down into
Carbohydrates are broken down by carbohydrase
Proteins are broken down by protease
Lipids are broken down by lipase
where is lipase made
Lipase is made by the pancreas and small intestine
what happens once food is broken down?
Once food molecules are completely digested to make soluble molecules, they leave the small intestine and enter the bloodstream to travel to the cells that need them
The body is kept fairly steady at 37 degrees
what enzyme is produced in stomach
The glands in the stomach produce pepsin (a protease enzyme) works best in an acidic pH –> this is suitable as these same glands produce relatively concentrated HCl in the stomach
what is the effect of pepsin and why is HCL effective to help pepsin do its job
This HCl allows pepsin to work efficiently, and also kills a lot of the bacteria that enters the stomach with the food
what does the stomach produce for the walls of the stomach
Stomach produces a thick layer of mucus that coats the stomach walls and stops it being digested by the acid and enzymes
how is a stomach ulcer formed
Stomach ulcer is when mucus is lost, acid production increases, walls are attacked by acid and enzymes which is quite painful
enzymes in the small intestine work best in which environment
Enzymes in the small intestine work best in an alkaline environment
what factor effects enzymes in the break down of food ( positive effect)
Enzymes work better when there is a larger surface area to volume ratio (SA:V)
lipids dont mix with what? and why does this effect break down in a negative way
Lipids don’t mix with watery liquids in digestive enzymes - they remain as large globules
SO, it is difficult for lipase to break them down
what does bile do
Bile emulsifies fat in food (breaks the large fat globule into smaller drops of fat)
what is the effect of fats being emulsified
By doing this, the fat now has a larger SA:V, and so digestion and the enzymes can work at a faster rate
what are the adaptations of Villi and microVilli
Adaptations of microvilli and villi:
1)Very large SA:V ratio which increases rate of diffusion
2)Very short diffusion distance due to thin walls which increases rate of diffusion
3)Near a rich blood supply which maintains a steep concentration gradient which increases the rate of diffusion
what is particulate matter
Particles in the air: pollutants, pollen, dust –> known as Particulate Matter (PM)
how to write Particulate Matter with its diameter
PM with a diameter of 10 micrometers = PM₁₀
PM with a diameter of 0.1-2.5micrometers it’s PM₀.₁-PM₀.₂
when are nano-particles visible
Nanoparticles are visible in light
why are nano-particles extremely reactive
Nanoparticles have an extremely high SA:V, so there is a large exposure to the surface which makes them extremely reactive, even compared to powder
what is the use of titanium nano particles
Glass coated in titanium oxide nanoparticles –> sunshine triggers a reaction –> dirt is broken down –> easily washed with water
what is titanium oxide and zinc oxide nano-particles used in
Titanium oxide and zinc oxide nanoparticles in modern sunscreens - coated with silica on an atomic level –> so that the sunscreen is better at blocking UV rays
what is nano-cages of gold used for
Nanocages of gold to deliver drugs to planned, specific places in the body –> nanoparticles can’t get into the healthy blood vessels in the body
Nanoparticles get into tumour –> laser is directed at it –> gold warms up quickly –> temperature of the tumour changes enough to change the protein shapes, so the tumour cells die –> healthy cells are not damages
what do silver nano-particles do and where can they be used
Silver nanoparticles inhibit the growth of microorganisms –> used in: fridges, sprays used to clean operating theatres, atimicrobial coatings, socks to prevent odour
what can be used to make nano-wires
Nanotubes can be used to make nanowires which can be used in very small circuits
what can be used to make extremely sensitive sensors
Nanotubes can be used to make very sensitive sensors –> for example they can detect tiny traces of a gas in people’s breath before an asthma attack
what makes nano-particles good enzymes
Large SA:V ratio make nanoparticles very good enzymes
HOWEVER, this same SA:V ratio makes them very flammable as they are very reactive - so a small spark near them can cause a huge explosion
