Chapter 3 B3 Pages 36-51

Question 1

What is a tissue?

Answer 1

A tissue is a group of cells with similar structure and function working together.

Question 2

What is an organ?

Answer 2

Organs are collections of tissues. Each organ contains several tissues, all working together to perform a specific function. For example, the stomach is an organ involved in the digestion of food.

Question 3

What is an organ system?

Answer 3

A whole multicellular organism is made up of a number of organ systems working together. Organ systems are groups of organs that all work together To perform specific functions. The way in which one organ functions often depends on other organ system.

Question 4

Describe the function of the small intestine

Answer 4

Absorption of soluble substances

Question 5

Describe the function of the liver

Answer 5

Production of bile

Question 6

Describe the function of the pancreas

Answer 6

Secretion of digestive enzymes

Question 7

Describe the function of the stomach

Answer 7

Site of some protein digestion

Question 8

Describe the structure and function of the mouth

Answer 8

Chew increase surface area to enzyme amylase to starch

Question 9

Describe the structure and function of the salivary glands

Answer 9

Enzyme called amylase catalyses reaction breaking down starch into simple sugars. Also contains mucus making the food easier to eat.

Question 10

Describe the structure and function of the gullet (oesophagus)

Answer 10

Has muscles in its wall. These muscles contract behind the food to push it along towards the stomach. This wave-like contraction is called peristalsis.

Question 11

Describe the structure and function of the stomach

Answer 11

Food is mixed with stomach acid the protein-digest enzymes work quickly. Stomach acid also kills bacteria.

Question 12

Describe the structure and function of the pancreas

Answer 12

Control glucose in the blood. Glucose levels tend to rise when eating causing insulin to be released causing excess glucose to convert to glycogen for storage in liver. When blood sugar drops, insulin secretion is replaced by glucagon which converts glucagon back to glucose.

Question 13

Describe the structure and function of the rectum

Answer 13

Semi-solid material (feces) collects in the rectum before leaving the body through the anus.

Question 14

Describe the structure and function of the liver

Answer 14

Produces a liquid called bile stored in the gall bladder, bile travels through bile duct into the small intestine. The bile breaks up fat.

Question 15

Describe the structure and function of the large intestine

Answer 15

Absorbs water into the blood, undigested food becomes more solid.

Question 16

Describe the function of the pancreas

Answer 16

Organ that makes and releases digestive juices containing enzymes to break down your food.

Question 17

Describe the function of the stomach

Answer 17

Organ where food is churned with digestive juices and acids

Question 18

Describe the function of the small intestine

Answer 18

Organ where small digested molecules are absorbed into the bloodstream.

Question 19

Describe the function of the large intestine

Answer 19

Organ where water passes back into the body, leaving solid waste.

Question 20

What are protein’s uses?

Answer 20

Act as hormones
Act as antibodies
Act as enzymes
Structural components such as muscle

Question 21

What are carbohydrate’s uses?

Answer 21

Broken down and used in cellular respiration

Support material in plants

Question 22

What are fats and oils uses?

Answer 22

Insulation

Efficient energy store

Question 23

What are carbohydrates?

Answer 23

Carbohydrates provides us with the fuel that makes all the other reactions in life possible. They contain the chemical elements carbon, and oxygen.

Question 24

What are all carbohydrates made up of ?

Answer 24

All carbohydrates are made up of units of sugars.

Question 25

What do some carbohydrates contain give an example?

Answer 25

Some carbohydrates contain only one sugar unit. The best known of these single is glucose, C H12 O6 .

Question 26

What are other carbohydrates made up of?

Answer 26

Other carbohydrates are made up of two sugar units joined together, e.g. sucrose, the compound we call,'Sugar,' in everyday life. These small carbohydrate units are referred to as simple sugars.

Question 27

What are complex carbohydrates made up of?

Answer 27

Complex carbohydrates such as starch and cellulose are made up of long chains of simple sugar units bonded together.

Question 28

Give some examples of carbohydrate rich foods.

Answer 28

Carbohydrate rich foods include bread, potatoes, rice and pasta.

Question 29

What are most of the carbohydrates we eat broken into?

Answer 29

Most of the carbohydrates we eat are broken down into glucose which is used in cellular respiration to provide energy fro metabolic reactions in your cells. The carbohydrate cellulose is an important support material in plants.

Question 30

What are lipids?

Answer 30

Lipids are fats (solids) and oils (liquids). They are the most efficient energy store in your body and an important source of energy in your diet.

Question 31

Why are lipids very important?

Answer 31

Combined with other molecules, lipids are very important in your cell membranes, as hormones, and in your nervous system.

Question 32

What are lipids made up of?

Answer 32

Like carbohydrates, lipids are made up of carbon, hydrogen and oxygen. All lipids are soluble in water.

Question 33

How man molecules and of what type are lipids made up of?

Answer 33

Lipids are made up of three molecules of fatty acids joined to a molecule of glycerol. The glycerol is always the same, but the fatty acids are different.

Question 34

What are lipid-rich foods?

Answer 34

Lipid-rich food includes all the oils, e.g. olive oil and corn oil, as well as butter, margarine, cheese and cream (dairy).

Question 35

What affects the lipid to be liquid or solid?

Answer 35

The different combination of fatty acids affects whether the lipid wil be a liquid oil or a solid fat.

Question 36

What are proteins used for?

Answer 36

Proteins are used for building up the cells and tissues of your body, as well as the basis of all your enzymes.

Question 37

How much of your body mass is made up of protein?

Answer 37

Between 15 and 16% of your body mass is made up of protein.

Question 38

Where is protein found?

Answer 38

Protein is found in tissues ranging from your hair and nails to the muscles that move you around and the enzymes that control your body and how it works.

Question 39

What are proteins made up of?

Answer 39

Proteins are made up of the elements carbon, hydrogen, oxygen and nitrogen. Protein-rich foods include meat, fish, pulses and cheese. A protein molecule is made up of long chains of small units called amino acids.

Question 40

what is the hierarchy of living organisms

Answer 40

Hierarchy of living organisms: cells􏰌 to tissues􏰌 to organs to 􏰌organ systems to 􏰌organisms

Question 41

state 3 food nutrients

Answer 41

carbohydrate proteins fats

Question 42

describe the food nutrient carbohydrate

Answer 42

Carbohydrate: composed of long chains of simple sugars e.g. glucose molecules

Question 43

describe the food nutrient protein

Answer 43

Proteins: composed of chains of amino acids

Question 44

describe the food nutrient fats

Answer 44

Fats: composed of 3 fatty acids & 1 glycerol molecule

Question 45

what do proteins act as

Answer 45

act as hormones act as antibodies act as enzymes acts as structural components such as muscle

Question 46

what are carbohydrates uses

Answer 46

broken down and used in cellular respiration | support material in plants

Question 47

what are fats and oils uses

Answer 47

insulation | efficient energy store

Question 48

what is the food test for starch

Answer 48

1 Place a small amount of food on the spotting tile. 2 Add a few drops of iodine solution to the food on the spotting tile. 3 Yellow–red iodine solution turns blue–black if starch is present. 4 Repeat steps 1–3 for other types of food. 5 Record all your results in a results table.

Question 49

what is the food test fo sugar

Answer 49

1 Place a small amount of food in a test tube. 2 Add enough Benedict’s solution to cover the food. 3 Place the test tube in a warm water bath for 10 minutes. 4 Blue Benedict’s solution turns brick red on heating if a sugar such as glucose is present. 5 Repeat steps 1–4 for other types of food. 6 Record all your results in a results table.

Question 50

what is the food test for lipids (fats)

Answer 50

1 Place a small amount of food into a test tube. 2 Add a few drops of ethanol to the test tube. 3 Shake the test tube and leave for one minute. 4 Pour the solution into a test tube of water. 5 Ethanol added to a solution gives a cloudy white layer if a lipid is present. 6 Repeat steps 1–5 for other types of food. 7 Record all your results in a results table.

Question 51

what is the food test for protein

Answer 51

1 Place a small amount of food in a test tube. 2 Add 1 cm3 of Biuret reagent. Alternatively, add 1 cm3 of sodium hydroxide solution and then add a few drops of copper sulfate solution. 3 Blue Biuret reagent turns purple if protein is present. 4 Repeat steps 1–3 for other types of food. 5 Record all your results in a results table.

Question 52

What is an enzyme?

Answer 52

An enzyme is a biological catalyst that speeds up the rate of chemical reactions in the body. Enzyme activity is affected by changes in temperature and pH.

Question 53

Explain how enzymes work

Answer 53

- Enzymes are proteins. They speed up the rate of chemical reactions. - They have a specific shape called the active site - The active site is complementary to the shape of the substrate molecule. Like a 􏰊lock and ke􏰃􏰋􏰇 - There are random collisions between the enzyme and the substrate molecule, when the substrate enters the active site an enzyme 􏰁 substrate complex is formed. - Bonds are broken - Produce are released. - Enzyme can then be reused.

Question 54

what do enzymes require

Answer 54

Enzymes require an optimum pH and temperature as they are proteins.

Question 55

what is the best temperature for enzymes

Answer 55

the optimum (best) temperature for enzymes is 37􏰍C (body temperature).

Question 56

what happens when increase the temperatures of the enzyme

Answer 56

Increasing temperatures: both the enzyme and substrate molecules have more kinetic energy, therefore there are more frequent collisions, more enzyme substrate complexes are formed and more products are released.

Question 57

what happens to the enzymes above 40 degrees celsius

Answer 57

Over 40°C the bonds in the enzyme start to break, therefore the enzyme starts to become denatured and no longer functions. The substrate can no longer fit into the active site.

Question 58

how does pH affect the enzyme

Answer 58

each enzyme has an optimum pH. They only work within a narrow range of pH. Higher/lower pHs cause the enzyme to become denatured.

Question 59

name three types of enzymes

Answer 59

protease lipase carbohydrase for example amylase

Question 60

where are protease found

Answer 60

the production site of protease are in the stomach the pancreas and the small intestine

Question 61

where are lipase found

Answer 61

the production site of lipase are in the pancreas and | the small intestine

Question 62

where are carbohydrase found

Answer 62

the production site of carbohydrase are in the salivary glands the pancreas and the small intestine

Question 63

where do the protease work

Answer 63

in the stomach and in the small intestine

Question 64

where do the lipase work

Answer 64

in the small intestine

Question 65

where do the carbohydrase work

Answer 65

in the mouth and the small intestine

Question 66

what are digestive enzymes

Answer 66

There are many different type of enzymes that speed up reactions in different parts of the digestive system. You need to know where these enzymes are made and where they function. See table below.

Question 67

what is bile

Answer 67

Bile: a green alkaline liquid produced by the liver and stored in the gallbladder. It neutralises stomach acid and emulsifies fats (which gives a larger surface area for the enzyme lipase to act).

Question 68

Where is food absorbed into the bloodstream

Answer 68

the small intestine

Question 69

Where is water reabsorbed back into the bloodstream

Answer 69

the large intestine

Question 70

what is the method to find out factors affecting enzymes

Answer 70

Method 1 Use the syringe to place 2 cm3 of amylase solution into a test tube. 2 Use another syringe to add 1 cm3 of pH buffer solution to the test tube. 3 Place the test tube into a water bath set at 30 C 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 2 cm3 of 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.