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Biology > B3-organisation and the digestive system > Flashcards

B3-organisation and the digestive system Flashcards

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1
Q

what is the pathway of digestion

A

mouth–>osophegus–>stomach–>pancreas, liver, gall bladder–>small intestine–>large intestine–> rectum –> anus

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2
Q

what is digestion

A

Digestion = the breakdown of large, insoluble molecules, to smaller soluble molecules

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3
Q

why must nutrients be soluble

A

Nutrients must be soluble so that they can dissolve into our blood plasma and be transported to the cells where they are needed

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4
Q

what do glands produce

A

Glands like pancreas and salivary glands release enzymes to break down food

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5
Q

what absorbs nutrients

A

Nutrients are absorbed into the blood from the small intestine

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6
Q

what absorbs water

A

Water is absorbed from the large intestine - once all the water has been absorbed into the blood, what’s left is faeces

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7
Q

how does food move in the intestines

A

Food moves through the intestines by the muscles squeezing –> peristalsis

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8
Q

what are our main food groups

A

Our main food groups are carbohydrates, proteins and lipids

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9
Q

what are polymers

A

These are all polymers - they are made up of smaller molecules to form one big molecule

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10
Q

what can our main food groups be broken down into

A

carbohydrates–> glucose
protein–> amino acids
lipids–>glycerol and fatty acids

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11
Q

what is glucose in terms of molecules

A

Glucose is a single sugar molecule

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12
Q

what are complex sugars and some examples

A

Complex carbohydrates like starch, cellulose are made up of simple sugar units bonded together

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13
Q

what are lipids important in

A

Lipids are important in your cell membranes, hormones and nerve cells

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14
Q

what are lipids

A

Lipids are fats and oils

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15
Q

why cant lipids dissolve in water

A

All lipids are insoluble in water

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16
Q

why are proteins important

A

15-20% of your body is protein. It is used to build your muscles, and enzymes, hormones, antibodies, antigens are all proteins

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17
Q

what are the appearance of protein and why are these shapes important

A

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

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17
Q

in terms of protein enzymes; what are bonds, what are they sensitive to and what happens when they are broken

A

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

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18
Q

whats the definition of enzyme

A

Enzyme = a biological catalyst - it increases the rate of reaction (speeds up) of chemical reactions in the body

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18
Q

what does catalyst mean

A

Catalysts = something that speeds up a chemical reaction without being used up - they can be used over and over again

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19
Q

why are enzymes special

A

Enzymes have a SPECIFIC shape, that allows them to bind to only ONE substrate

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19
Q

what are enzymes

A

Enzymes’ are large protein molecules and their shape is really important to their function

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20
Q

what is the lock and the key in the lock and key model

A
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21
Q

FUN FACT: Enzymes can join together small molecules as well as break large ones up

A

FUN FACT: Enzymes can join together small molecules as well as break large ones up

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22
Q

What do enzymes control

A

Enzymes control metabolism

23
Q

what does metabolism mean

A

Metabolism = the sum of all the reactions in a cell or in the body

24
Q

what are some reactions that enzymes catalyse

A

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

24
Q

Draw and explain the temperature graph for enzymes

A

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

25
Q

what is the normal temperature for humans

A

37°C

26
Q

describe and explain the enzymes graph

A

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

27
Q

Draw the pH graph for enzymes
Search up and mark - symmetrical graph, doesnt start at 0, y-axis=rate of reaction, x-axis=p

A

Search up and mark - symmetrical graph, doesnt start at 0, y-axis=rate of reaction, x-axis=pH

28
Q

describe and explain the ph graph for rate of reaction on enzymes

A

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

29
Q

what are extremophiles

A

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

30
Q

where are the different types of enzymes found

A

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?)

31
Q

what are the enzymes broken down into

A

Carbohydrates are broken down by carbohydrase
Proteins are broken down by protease
Lipids are broken down by lipase

32
Q

where is lipase made

A

Lipase is made by the pancreas and small intestine

33
Q

what happens once food is broken down?

A

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

34
Q

what enzyme is produced in stomach

A

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

35
Q

what is the effect of pepsin and why is HCL effective to help pepsin do its job

A

This HCl allows pepsin to work efficiently, and also kills a lot of the bacteria that enters the stomach with the food

36
Q

what does the stomach produce for the walls of the stomach

A

Stomach produces a thick layer of mucus that coats the stomach walls and stops it being digested by the acid and enzymes

37
Q

how is a stomach ulcer formed

A

Stomach ulcer is when mucus is lost, acid production increases, walls are attacked by acid and enzymes which is quite painful

38
Q

enzymes in the small intestine work best in which environment

A

Enzymes in the small intestine work best in an alkaline environment

39
Q

what factor effects enzymes in the break down of food ( positive effect)

A

Enzymes work better when there is a larger surface area to volume ratio (SA:V)

40
Q

lipids dont mix with what? and why does this effect break down in a negative way

A

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

41
Q

what does bile do

A

Bile emulsifies fat in food (breaks the large fat globule into smaller drops of fat)

42
Q

what is the effect of fats being emulsified

A

By doing this, the fat now has a larger SA:V, and so digestion and the enzymes can work at a faster rate

43
Q

what are the adaptations of Villi and microVilli

A

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

44
Q

what is particulate matter

A

Particles in the air: pollutants, pollen, dust –> known as Particulate Matter (PM)

45
Q

how to write Particulate Matter with its diameter

A

PM with a diameter of 10 micrometers = PM₁₀
PM with a diameter of 0.1-2.5micrometers it’s PM₀.₁-PM₀.₂

46
Q

when are nano-particles visible

A

Nanoparticles are visible in light

47
Q

why are nano-particles extremely reactive

A

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

48
Q

what is the use of titanium nano particles

A

Glass coated in titanium oxide nanoparticles –> sunshine triggers a reaction –> dirt is broken down –> easily washed with water

49
Q

what is titanium oxide and zinc oxide nano-particles used in

A

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

50
Q

what is nano-cages of gold used for

A

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

51
Q

what do silver nano-particles do and where can they be used

A

Silver nanoparticles inhibit the growth of microorganisms –> used in: fridges, sprays used to clean operating theatres, atimicrobial coatings, socks to prevent odour

52
Q

what can be used to make nano-wires

A

Nanotubes can be used to make nanowires which can be used in very small circuits

53
Q

what can be used to make extremely sensitive sensors

A

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

54
Q

what makes nano-particles good enzymes

A

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

55
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56
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57
Q
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Biology (4 decks)

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