7: Human Nutrition

Question 1

What are lipids made of?

Answer 1

Fatty acids and glycerol

Question 2

What are proteins made of?

Answer 2

amino acids

Question 3

What are carbohydrates?

Answer 3

They can be simple sugar molecules such as glucose or larger, more complex molecules such as starch, glycogen or cellulose. These complex carbohydrates are made of many individual glucose molecules joined together into chains

Question 4

What do organisms use nutrients for?

Answer 4

1: Growth
2: As a source of energy
3: For repair or respiration

Question 5

What is a balanced diet?

Answer 5

A balanced diet includes all essential nutrients in the correct amounts needed by an organism for energy, growth, repair & replacement and to remain healthy

Question 6

State the principal dietary sources and describe the importance of carbohydrates

Answer 6

Principal dietary sources: rice, pasta, bread, potatoes, cereal products
Importance of carbohydrates: Energy source and storage

Fibres: prevent constipation and concentration of cholesterol
Starch: store excess energy
Sugars: produce energy

Question 7

State the principal dietary sources and describe the importance of fats and oils

Answer 7

Principal dietary sources: butter, cheese, fats in meats & fish, nuts
Importance of fats and oils: store energy, insulation, make membranes, buoyancy

Question 8

State the principal dietary sources and describe the importance of proteins

Answer 8

Principle sources of protein: meat, fish, beans, eggs, milk, nuts, potatoes
Importance: bodybuilding, making new body tissues, repairing worn/damaged tissues, energy

Question 9

State the principal dietary sources and describe the importance of vitamins C and D

Answer 9

Principal dietary sources: (vitamin c) grapefruit, oranges, melon, lemons, tomatoes, potatoes, strawberries (vitamin d) eggs, liver, white fish, sardines, milk
Importance: prevents scurvy (vitamin c) and rickets (vitamin d)

Question 10

State the principal dietary sources and describe the importance of mineral ions (calcium and iron)

Answer 10

principal dietary sources: (calcium) milk, cheese, bread, flour products (iron) meat, green vegetables and potatoes
importance: prevent rickets (calcium) and prevent anaemia (iron)

Question 11

State the principal dietary sources and describe the importance of fibre (roughage)

Answer 11

principal dietary sources: vegetables etc

importance: gives diet bulk and helps digestive system to work properly and prevents constipation

Question 12

State the principal dietary sources and describe the importance of water

Answer 12

principal dietary sources: water

importance: stay hydrated

Question 13

What causes scurvy and rickets?

Answer 13

Scurvy: lack of vitamin C
Rickets: lack of vitamin D

Question 14

What is the liver?

Answer 14

A large, important gland that makes bile to emulsify fats so they can mix with the digestive juices in the small intestine

Question 15

What is the gall bladder?

Answer 15

stores bile made by the liver

Question 16

What is the duodenum?

Answer 16

first part of the small intestine. bile and juice from the pancreas are added to the food in the duodenum

Question 17

what is the function large intestine/colon?

Answer 17

absorbs water from the chyme (the pulpy acidic fluid which passes from the stomach to the small intestine, consisting of gastric juices and partly digested food) into the blood, leaving the solid waste called faeces. Minerals are also absorbed.

Question 18

what is the caecum?

Answer 18

first part of the large intestine

Question 19

what is the appendix?

Answer 19

plays no part in digestion and is of little value in humans (attached to the end of the caecum)

Question 20

what is the rectum?

Answer 20

last part of the large intestine

Question 21

what is the oesophagus/gullet

Answer 21

tube from mouth to stomach

Question 22

what is the stomach?

Answer 22

> acts as a reservoir for food while it is churned and mixed with the gastric juice.
the juice contains hydrochloric acid to kill germs, pepsin, an enzyme to digest protein, and rennin, an enzyme to clot milk, making it easier to digest
the acid chyme formed is eventually squirted into the duodenum

Question 23

What are the 4 types of sphincter?

Answer 23

1: Cardiac sphincter
2: Pyloric sphincter
3: ileocaecal sphincter
4: anal sphincter

Question 24

what is the pancreas?

Answer 24

a gland which makes pancreatic juice. This juice is alkaline to neutralise the stomach acid. it contains proteases, lipases and amylases. pancreatic juices are emptied into the duodenum

Question 25

what is the small intestine? (or ileum)

Answer 25

a tube about 6m long. it makes enzymes to complete the digestive process. the soluble nutrients formed are mostly absorbed through its walls into the blood, leaving little of value to enter the colon.

Question 26

define ingestion

Answer 26

the taking of substances, e.g. food and drink, into the body through the mouth

Question 27

define digestion

Answer 27

the breakdown of food

Question 28

define absorption

Answer 28

uptake and use of nutrients by cells

Question 29

define assimilation

Answer 29

the movement of nutrients from the intestine into the blood

Question 30

define egestion

Answer 30

the removal of undigested food from the body as faeces

Question 31

give the regions of the alimentary canal involved and the associated organs involved with the process of ingestion

Answer 31

regions: mouth and oesophagus | associated organs: salivary glands

Question 32

give the regions of the alimentary canal involved and the associated organs involved with the process of digestion

Answer 32

regions: stomach, ileum, small intestine, duodenum | associated organs: liver, pancreas, gall bladder, salivary glands

Question 33

give the regions of the alimentary canal involved and the associated organs involved with the process of absorption

Answer 33

regions: colon, large intestine, small intestine, ileum, duodenum associated organs: body cells

Question 34

give the regions of the alimentary canal involved and the associated organs involved with the process of assimilation

Answer 34

region: small intestine, duodenum, ileum | associated organs: body cells

Question 35

give the regions of the alimentary canal involved with the process of egestion

Answer 35

rectum and anus

Question 36

define physical digestion

Answer 36

the breakdown of food into smaller pieces without chemical change to the food molecules

Question 37

why does physical digestion occur?

Answer 37

in order to increase the surface area of food for the action of enzymes in the chemical digestion

Question 38

name the 4 different types of teeth

Answer 38

incisors, canine, premolars and molars

Question 39

what is the incisor used for

Answer 39

cutting food (chisel shaped teeth)

Question 40

what is the canine used for

Answer 40

gripping and tearing food (sharp)

Question 41

what are the premolars and molars used for

Answer 41

grinding and crushing food (flat topped, have points/cusps)

Question 42

what is the small flap of cartilage that closes over the opening to the trachea/glottis called and why is it important?

Answer 42

epiglottis, to prevent food from going to your lungs

Question 43

what is the function of the enamel?

Answer 43

protects the tooth from physical, chemical and thermal forces

Question 44

what is the function of the dentine?

Answer 44

reinforces the tooth's enamel

Question 45

what is the function of the pulp cavity?

Answer 45

contains pulp which carries nerves to give the tooth feeling and blood vessels to feed the tooth

Question 46

what is the function of the nerves in the tooth?

Answer 46

sense hot and cold

Question 47

what is the function of the blood vessels in your teeth?

Answer 47

provide teeth with nutrients

Question 48

what is the function of the cement?

Answer 48

fixes tooth to jaw

Question 49

what is the function of the gum?

Answer 49

keeps tooth in place

Question 50

what is peristalsis

Answer 50

rhythmic squeezing and relaxing by the muscles to help mix up food with juices and bring it up against the walls so that it can be absorbed by the blood

Question 51

describe physical digestion by bile

Answer 51

the main function of bile is to emulsify fats and increase the surface are so that the enzymes can work more efficiently

Question 52

define chemical digestion

Answer 52

the breakdown of large, insoluble molecules into smaller, soluble molecules. Its role is to produce molecules that can be absorbed

Question 53

why does starch digestion stop in the stomach?

Answer 53

the optimum pH for amylase is 7.0, so the highly acidic conditions in the stomach would denature them.

Question 54

describe the function of protease

Answer 54

breaks down protein to amino acids

Question 55

describe the function of amylase

Answer 55

breaks down starch to simple reducing sugars

Question 56

describe the function of lipase

Answer 56

breaks down fats and oils into fatty acids and glycogen

Question 57

what is absorption?

Answer 57

the movement of nutrients from the intestines into the blood

Question 58

list the adaptations to help the small intestine absorb food.

Answer 58

>long tube, has ridged walls covered with finger-like projections called villi and these are covered in cells with projections called microvilli. this gives a very large surface area for exchange >rich blood supply - large surface area for exchange > has lacteals which help with the absorption of less soluble materials