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Biology > B2 - Principles Of Organisation And Digestion > Flashcards

B2 - Principles Of Organisation And Digestion Flashcards

1
Q

What is a tissue?

A

A tissue is an aggregation of cells with a similar structure and function

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2
Q

What is an organ?

A

An organ is an aggregation of tissues working together to perform a particular function

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3
Q

What is an organ system?

A

An aggregation of organs, which work together to form functioning organisms

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4
Q

What is a cell?

A

The basic building block of all living organisms

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5
Q

Why does food need to be digested?

A

To break down large, insoluble biological molecules into small, soluble ones by enzymes so that they can be absorbed in the bloodstream

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6
Q

What are the function of digestive enzymes?

A

Digestive enzymes convert food into small, soluble molecules that can be absorbed into the bloodstream

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7
Q

What digestive enzyme breaks down carbohydrates?

A

Carbohydrases.

Amylase is a carbohydrase which breaks down starch into maltose

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8
Q

What digestive enzyme breaks down protein?

A

Proteases

Example: Pepsin

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9
Q

What digestive enzyme breaks down lipids (fats)?

A

Lipases

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10
Q

What are the products of digestion used for?

A

The products of digestion are used to build new carbohydrates, lipids and proteins.

Some glucose is utilised in cellular respiration

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11
Q

Where is bile made, stored and released?

A

Bile is made in the liver, stored in the gall bladder and released into the small intestine

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12
Q

What is the function of bile?

A

Bile catalyses the digestion of lipids by converting large lipid droplets into smaller ones.

It is not an enzyme

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13
Q

Explain how bile increases the rate of lipid breakdown by lipase

A

Bile emulsifies lipids to form small droplets. This increases the S.A for enzymes to act on. Bile also is alkaline to neutralise HCI from the stomach (enzymes in the small intestine have a more alkaline pH than those in the stomach) so that the enzymes do not denature. These both increase the rate of lipid breakdown by lipase to form fatty acids and glycerol

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14
Q

(i) What is the qualitative reagent test for
carbohydrates/sugars? What is its positive result?

(ii) What are the different types of carbohydrate that can be tested for?

A

(i) Benedict’s solution.

Positive result: Blue -> Green/yellow/brick-red precipitate, depending on concentration

(ii) Glucose using Benedict’s and starch using iodine

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15
Q

How is the small intestine adapted for absorption?

A

Long in length at around 5m. This increases the surface area for absorption of the products of digestion

Interior is covered with villi. Microvilli on the surface increase the surface area further

Rich blood supply in vili. This allows for the bloodstream to remove the products of digestion, increasing the concentration gradient

Villi have a thin membrane. This ensures a short diffusion pathway

High yield of mitochondria in intestine lining cells to release energy for any molecules that cannot be absorbed into the bloodstream by diffusion and require active transport

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16
Q

What do carbohydrases break down carbohydrates into?

A

Simple sugars

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17
Q

What do proteases break down proteins into?

A

Individual amino acids, which are then absorbed into the bloodstream

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18
Q

What do lipases break down lipids into?

A

Glycerol and fatty acids. This makes the pH more acidic

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19
Q

What is the qualitative reagent test for starch? What is its positive result?

A

Iodine solution

Positive result: Orange -> blue/black

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20
Q

Where is amylase, a carbohydrase that breaks down starch into sugar (maltose), produced? [SgPSm]

Where does it work?

A

Produced in:

Salivary glands
Pancreas
Small intestine

Works in:

Mouth
Small intestine

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21
Q

Where is protease produced? [SPSm]

Where does it work?

A

Produced in:

Stomach
Pancreas
Small intestine

Works in:

Stomach
Small Intestine

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22
Q

Where is lipase produced? [SP]

Where does it work?

A

Produced in:

Pancreas and small intestine

Works in:

Small intestine

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23
Q

What is the function of the stomach?

A

Produces HCI to kill bacteria and to provide the optimum pH for the protease enzyme to function

24
Q

What is the function of the small intestine?

A

The site where soluble molecules are absorbed into the blood by cellular transport

25
What is the function of the liver?
Releases bile into the small intestine to emulsify fat and neutralise stomach acid
26
What is the function of the large intestine?
Absorbs water from undigested food to produce faeces. This passes out of the body through the rectum and anus
27
Without bile to neutralise acid in the stomach, the enzymes would become ______
Denatured
28
Amino acids are used to build proteins such as _______ and ________
Enzymes and antibodies
29
Fatty acids and glycerol can be used to build new ____________ and ____________
Cell membranes and hormones
30
Some glucose released from carbohydrate breakdown is used in ______ to release energy to fuel all the activities of the cell
Respiration
31
What is the function of muscular, glandular and epithelial tissue?
Muscular tissue - moves the stomach walls to churn food Glandular tissue - makes digestive juices Epithelial tissues - covers the outside and inside of the stomach
32
What is the digestive system?
Several organs working together to digest and absorb food
33
What are enzymes?
Enzymes are biological catalysts that are 3D, large (tertiary) proteins made up of a chain of amino acids
34
Enzymes catalyse specific reactions in living organisms due to the ____ of their ________
Shape Active site
35
What is the lock and key theory model of enzyme action?
The substrate is perfectly complementary to the active site. This forms an enzyme-substrate complex and products
36
What factors affect enzyme action?
Temperature pH
37
What is a catalyst?
A substance which increases the rate of reaction without getting used up
38
Describe the process of human digestion
Mouth -> mechanically churns food. Salivary glands produce salivary amalyse to digest insoluble food molecules. This passes through the oesophagus into the stomach Stomach -> pummels food with muscular walls, produces pepsin and HCI. Churning action turns food into fluid, increasing S.A for enzymes Small intestine -> Bile released into the small intestine, which increases the rate of fat breakdown. All digestive enzymes break down large, insoluble molecules into small, soluble ones to be absorbed in the bloodstream through diffusion or active transport Wastage —> Fluid goes to large intestine. Excess water absorbed into the bloodstream. Faeces stores in rectum before leaving through anus
39
Describe a method to prepare food samples
Break food using pestle and mortar Add distilled water Stir and filter to remove insoluble bits of food
40
Describe a method to test for sugars
Transfer 5cm³ of food sample to a test tube Prepare a water bath at 75 degrees Celsius Add 10 drops of Benedict’s solution Place each test tube in water bath for five minutes If green —> small concentration of sugar If yellow —> moderate concentration If Red —> highest concentration
41
Describe a method to test for starch
Transfer 5cm³ of food sample to a test tube Add 3 drops of iodine solution Positive result is blue-black
42
Describe a method to test for proteins
Transfer 2cm³ of food sample to a test tube Add 2cm³ of Biuret solution Positive result is purple from blue
43
Describe a method to test lipids (write both methods)
Transfer 5cm³ of food sample to a test tube Use a pipette to add three drops of Sudan III If a red layer forms, lipids are present
44
Suggest how damage to the mucus lining of the stomach might result in a stomach ulcer forming
Bacteria not killed by HCI so damage the mucus lining So acid damage tissues
45
Explain how temperate affects how enzymes function
46
Explain how enzymes break down substrates
Substrate fits into active site of the enzyme Shape of active site is specific to the enzyme and forms an enzyme-substrate complex Bonds within substrate are broken Enzyme is not used up !
47
Give one industrial use of carbohydrase, isomerase and protease
Carbohydrase -> converts starch info sugars Isomerase -> converts glucose syrup to fructose syrup Protease -> pre-digests proteins in baby food
48
Describe a method to investigate the effect of pH on the rate of reaction of amylase enzyme.
1. Set up a water bath or electric heater at 25-35 degrees 2. Place 3 drops of iodine solution into each well of a spotting tile 3. Using a syringe, place a 2cm³ solution of amylase, starch and pH 5 buffer solution into three different boiling tubes 4. Place all three boiling tubes into the water bath and wait 5 minutes for them to equilibrate 5. Mix the boiling tubes and start a timer 6. Every 30 seconds, place a drop from the boiling tube into the well 7. Continue step 6 until the well remains orange. At this point, the starch has been fully digested. Record this time 8. Repeat the investigation using different pH buffer solutions such as 7 and 12 9. Repeat for each pH three times, remove anomalies and calculate a mean rate of reaction 10. Calculate the rate of reaction using: Reaction = 1000/time
49
What is the IV, DV and CV for investigating the effect of pH on the rate of reaction of amylase enzyme? How can the investigation be improved?
IV- pH DV- CV- Temperature
50
Suggest an explanation as to why the rate of reaction is slow at certain pH levels
High and low pH values may cause bonds holding enzymes’ structure together to break
51
Explain how the cells of the pancreas are specialised to produce enzymes
- Pancreatic cells have many ribosomes. This is the site of protein synthesis - Many mitochondria to release energy for protein synthesis
52
Read questions in exams TWICE for every subject
53
Describe the structure of the heart
Muscular walls to provide a strong heartbeat The muscular wall of the left ventricle is thicker, because blood needs to be pumped all around the body Four chambers that separate oxygenated blood from the deoxygenated blood Valves to make sure the backflow of blood does not occur Coronary arteries cover the heart to provide its own oxygenated blood supply
54
Where is carbohydrase produced?
55
A person has a tumour blocking the tube leading from the gall bladder to the small intestine ExplaIn why this person would have difficulty digesting fat (5)
- No bile reaches the small intestine - So less emulsification fat - So smaller surface area for lipase to break down fat - pH of small intestine is not neutralised/alkaline - So lipase is not at its optimum pH to break down fat

Biology (9 decks)

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