B3-Digestion Flashcards

1
Q

Test for starch

A

Add iodine solution to food and it should turn from a red yellow to a blue/ black

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2
Q

Test for sugar

A

Add Benedicte solution to cover food
Leave warm water bath 10minutes
Turns brick red when heated if glucose

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3
Q

Test for lipids(fat)

A

Few Drops ethanol to food
Shake and leave 1minute
Pour solution into a test tube of water
If ethanol creates cloudy white layer lipid is present

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4
Q

Test for protein

A

Add 1cm3 blue biuret or sodium hydroxide and copper sulfate solution
Turns purple if present

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5
Q

What are enzymes

A

are special proteins involved in ‘metabolism’ (reactions in the body) and help to speed up reactions. Some enzymes help build molecules, some break molecules down, others change one molecule into another.

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6
Q

What are digestive enzymes

A

break down food into smaller soluble molecules that can be absorbed into the bloodstream.
“Biological catalysts”

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7
Q

Carbohydrate (enzyme that breaks nutrient down, where and what are products)

A

Carbohydrase enzyme
Small intestine and mouth but also made in pancreas
Sugar

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8
Q

Proteins (enzyme that breaks nutrient down, where and what are products)

A

Protease enzyme
Produces by stomach, pancreas and small intestine and takes place in stomach and small intestine
Amnio acids

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9
Q

Fats (enzyme that breaks nutrient down, where and what are products)

A

Lipase enzyme
Made in pancreas and passed into the small intestine
Fatty acids and glycerol

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10
Q

What is bile

A

Made in liver but stored in gall bladder
Alkaline to neutralise hydrochloric acid from stomach
Emulsifies to form small droplets
Produces a large surface area for lipase to eat on
Turns large droplets-small droplets

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11
Q

Keeping the pH in your digestive system at optimum levels is difficult because

A

enzymes work best at different pH levels. So, your body creates a variety of different chemicals that help to keep conditions optimum for your enzymes.

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12
Q

As the temperature increases

A

reactivity increase as there is more kinetic energy so more random collision
but after their optimal temperature the protein structure is affected as the active site is affected so the substrate can no longer fit so it becomes denatured and is irreversible

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13
Q

Carbohydrates

A

All carbohydrates are made up of units of sugar.Some carbohydrates contain 1 unit of sugar e.g glucose. Other carbohydrates made up 2units of sugar (simple sugars) e.g, sugar. Complex carbohydrates have long chains of simple sugars bonded e.g. starch, cellulose. Carbohydrates provide us with energy for everything else and they contain hydrogen, carbon and oxygen. Rice, pasta, potatoes and rice are carbon rich foods. Carbohydrates we eat get broken down into glucose used in cellular respiration to provide energy for metabolic reactions in your cells

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14
Q

Lipids

A

Lipids are made up of three molecules of fatty acids joined to a molecule of glycerol which is always the same but the fatty acids vary in combination whether they will be a liquid oil or a solid fat. Lipids are fats and oils, most efficient energy store and important source of energy in your diet, combined other molecules are important in cell membranes as hormones in your nervous system and contain same as carbohydrates. Lipid rich food:oils e.g olive and sunflower oil, butter, margarine, cheese and cream

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15
Q

Proteins

A

Long chains of amnio acids 20 different ones of them joined by special bonds different arrangements various give different proteins. Have specific 3d shapes so other molecules can fit bonds can be broken easily. Act as:
-Structural components of tissues such as muscles and tendons
-Hormones such as insulin
-antibodies destroy pathogens part of immune system
-enzymes! act as catalyst
15-16 body mass is protein which found in tissues e.g. nails, hair, muscles,enzymes etc. Proteins are made up of carbon, hydrogen, oxygen and nitrogen. Protein rich foods:meat, fish, pulses and cheese

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16
Q

Qualitive

A

subjective judgements about a quantity

17
Q

Quantitative

A

measurements taken in numberical values

18
Q

more lipids there are in an item of food, the more cloudy the positive result is.
Suggest how you could use this information to help you to measure the amount of lipids present in different items of food.

A

Get piece of text see how clear it is behind the test tube (qualitative judgement)
Use colorimeter to measure light transmission/ through test tube with flashlight (quantitative)

19
Q

Required practical 5 effect of pH on rate of reaction amylase-method

A

1 Use the syringe to place 2cm3of amylase solution into a test tube.
2 Use another syringe to add 1cm3 of pH buffer solution to the test
tube.
3 Place the test tube into a water bath set at 30C degrees and leave for 5
minutes.
4 Whilst waiting, add a drop of iodine solution into each dimple of a
spotting tile.
5 After 5 minutes, use another syringe to add 2cm3of starch to the
amylase/buffer solution, start the stop clock and leave it on
throughout the test. Mix using a plastic pipette.
6 Remove a drop of amylase/starch/buffer mixture after 30 seconds
and add to the first drop of iodine on your spotting tile.
7 Wait another 30 seconds. Then remove a second drop of the
mixture to add to the next drop of iodine.
8 Repeat step 6 until the iodine solution and the
amylase/buffer/starch mixture remains orange.
9 Record the time taken for the amylase to fully digest the starch.
10 Repeat the whole procedure with a different pH buffer.

20
Q

Required practical 5 effect of pH on rate of reaction amylase- safety

A

Use eye protection.

Iodine is harmful, avoid contact with skin.

21
Q

Digestion of bread

A

As bread is a carbohydrate it is broken down into glucose used in cellular respiration to provide energy for metabolic reactions in your cells. Teeth and tongue grind food into smaller pieces (increase surface area) and salivary glands break down starch into simpler sugars +mucus makes it easier to swallow. Then muscles contract behind food to push it along and contraction of thick muscular wall churn into a liquid and kill bacteria in the stomach. Then bile from the liver transports to the small intestine breaks down fats into liquids and so it is ready for lipase to break it down into smaller molecules. Colon absorbs water into blood and undigested material becomes solid. Finally, faeces collect in the rectum and leaves the body via the anus.

22
Q

Smallest-largest cells which make up each other

A

Cells->tissue->organs->organ system->organism

23
Q

Role of the mouth in digestion

A
  • Teeth and tongue grind food into smaller pieces and increase surface area
  • salivary glands produce enzyme called amylase that catalyses the reaction that breaks down starch into simpler sugars and mucus makes it easier to swallow
24
Q

Role of the oesophagus in digestion

A
  • Have muscles in the wall

- Muscles contract behind food to push along towards the stomach (called peristalsis)

25
Q

Role of the stomach in digestion

A
  • food enters stomach through ring of muscle called the sphincter
  • contractions of thick muscullar wall churn food into liquid called chyme
  • acid kills bacteria that are ingested with the food and helps it work efficiently
  • food is mixed with stomach acid so that protein digesting enzyme (proteases) have the correct pH to work efficiently
26
Q

Role of the liver in digestion

A
  • Liver Produces liquid called bile
  • stored in gall bladder
  • bile duct transports to small intestine
  • bile breaks down fats in the food into smaller droplets which can mix with watery liquids (called emulsification)
27
Q

Role of the gallbladder in digestion

A

Where bile is stored

28
Q

Role of the pancreas in digestion

A
  • Secretes hormones that control glucose levels in blood
  • which rise after eating which causes insulin to be released which causes excess glucose to be converted into glycogen and stored here
  • when it drops insulin replaced by glucogen which converts glycogen back to glucose
29
Q

Role of the small intestine in digestion

A

Made up of duodenum and ilium

  • bile enters duodenum after a meal to break fat it up into tiny droplets
  • ready for lipase to break it down
  • glands in the ilium produce more enzymes to break down the food so that digested food passes through the wall of the ilium into the bloodstream
30
Q

Role of the large intestine in digestion

A

Made up the colon, appendix and rectum. Only indigestible materials and water remain when it gets here

  • colon absorbs the water into blood and the undigested material becomes solid
  • semi solid material (faeces) collects in the rectum before leaving the body via the anus
31
Q

Independent and dependent variable of required practical 5

A

The independent variable is pH buffer as we change that in the experiment and the dependent variable is the rate of the reaction

32
Q

Control variable in required practical 5

A

The time taken in between like 5minutes etc and we used a timer on our iPads to make sure we knew when the time was up

33
Q

Why use a buffer in required practical 5

A

Reaction begins as soon as they are put together so use a buffer.

34
Q

effect of pH on the rate of an amylase controlled reaction.

A

At optimal pH substrates bind to enzymes and are broken down into products efficiently because the active site is the right shape and complementary, the rate of reaction drops as you move away from the optimum because increasingly the active site is no longer complementary as the substrate no longer fits in the active rate of reaction decreases.