Chapter 6 - Nutrition & Digestion Flashcards
0
Q
What is malnutrition?
A
It occurs in both under developed countries and developed countries.
In underdeveloped countries, it means undernutrition, where the diet may be neither balanced nor adequate.
In developed countries, it usually means the diet is more than adequate just not balanced.
1
Q
What is the ideal diet?
A
A balanced diet includes carbohydrates, lipids, proteins, vitamins, mineral ions and dietary fibre. Sufficient water is also needed.
2
Q
What are carbohydrates made up of?
A
Carbon, hydrogen and oxygen.
3
Q
What are carbohydrates used for?
A
They provide the main source of energy for immediate use.
4
Q
Can our bodies manufacture carbohydrates?
A
No, so we need to get them from plants and animals.
5
Q
How are excess carbohydrates stored?
A
As glycogen in the liver and muscles.
As fat under the skin.
6
Q
How do plants synthesis carbohydrates?
A
Photosynthesis.
7
Q
There are 2 types of carbohydrates. State them below.
A
Sugars and starch.
8
Q
What is glucose used for?
A
It’s a form of transport in the body.
9
Q
Where do we find fructose mainly?
A
Fruit and honey.
10
Q
What is sucrose?
A
Common household sugar.
Formed with fructose and glucose.
11
Q
Where do we find lactose?
A
Occurs naturally in humans and cow’s milk.
12
Q
How is starch used in plants?
A
It stores food in plant seed.
Unripe fruit contains starch which is converted into sugar when it ripens.
13
Q
There are 2 main types of starch. Name them.
A
Cellulose, which is the major component in plant walls. Giving strength and rigidity to the plant.
Pectin which is present in apples and turnips.
14
Q
Mention a couple of food products which are rich in carbohydrates.
A
Potatoes, pasta and wholewheat bread.
15
Q
What are proteins made up of?
A
Carbon, hydrogen, oxygen and nitrogen.
Sometimes sulphur and phosphorus.
16
Q
Proteins are long chains of what?
A
Amino acids.
Forming dipeptides and polypeptides.
17
Q
How many amino acids are there?
A
There are 20 different amino acids.
18
Q
There are 2 kinds of amino acids. State them below.
A
Non-essential are amino acids that can be changed into other forms within the body.
Essential are the 8 amino acids that cannot be formed in this way, and have to be taken in. Eg: Lysine.
19
Q
What are proteins functions?
A
For growth and repair of muscle, skin tissue and bone.
To produce hormones, enzymes and antibodies.
To give energy.
For making haemoglobin.
20
Q
Mention a few food products which are rich in protein.
A
Cheese, rice, eggs and chicken.
21
Q
What are lipids made up of?
A
Carbon, hydrogen and oxygen.
22
Q
What are lipids composed of?
A
1 glycerol + 3 fatty acids.
23
Q
What unique property do lipids possess?
A
They are insoluble in water.
But soluble in organic solvents.
24
What are some good food sources for lipids?
Butter, cheese and meat.
25
What are lipids functions within the body?
They provided a lot of energy.
Component of cell membrane.
Form fatty tissues under the skin acting as insulator to keep warm.
Stored as fat around vital organs. Eg: kidney to protect them.
Acts as a solvent for important fat-soluble vitamins such as A, D, E, K.
26
One of the tests for lipids is the spot test. Explain it.
Oil leaves a permanent translucent spot on filter paper.
27
What are vitamins properties in general?
Although they have no energy value, they are essential in small amounts for good health.
Excessive amounts may be harmful.
28
Which vitamins are water soluble?
Vitamin B & C
29
Which vitamins are fat soluble?
Vitamins A, D, E and K
30
What does vitamin A provide for the body? Also where can it be found?
It is required for good vision; healthy hair, skin and nails.
You can find it in egg yolk, milk, cheese, carrots and green vegetable.
31
A deficiency in vitamin A, can cause what?
Night blindness,
32
What is vitamin C required for? Where can it be found?
It is required for binding of the cells and to maintain fitness.
It can be found is fresh fruits and green vegetables.
33
What can a deficiency in vitamin C lead to?
Scurvy
34
What is vitamin D required for? Where can it be found?
It is required for the uptake of calcium and phosphorus. Also for healthy teeth and bones.
Can be found in cod liver oil and egg yolk.
35
What can a deficiency in vitamin D cause?
Rickets.
36
Why are minerals important?
They are important for the health of living organism since they regulate body metabolism and are necessary for construction certain tissues.
Included Ca, S, K, Na, Mg, Fe, I.
37
What is calcium and phosphorus function and where can it be found?
It's needed for making bones and teeth, also important for blood clotting and muscle contractions.
Found in cheese, milk and vegetables.
38
What does a deficiency in calcium and phosphorus lead to?
Rickets.
39
Why is sodium important for the body, and where can it be found?
It's present in extra cellular fluid and it regulates it.
Found in salt and many food.
40
What does a deficiency in sodium lead to?
Cramps.
41
Why is iodine important and where can we find food rich in this substance?
Needed to synthesise hormones of the thyroid gland.
Found in sea food, drinking water.
42
What does a deficiency in iodine cause?
Goitre.
43
What is fluorine found in? Also, why is it important?
It builds a layer above the enamel.
Found in water and toothpaste.
44
What can an insubstantial amount of fluorine lead to?
It can lead to tooth decay.
45
Why is magnesium important?
It's needed for metabolism and is found in most food.
46
What can an insubstantial amount of magnesium lead to?
Tremors and convulsions.
47
What food profits are rich in iron, and why do we need it for the body?
It's a structural component of haemoglobin.
It can be found in liver, eggs, beef, green leafy vegetables.
48
What does iron deficiency lead to?
Anaemia.
49
What is fibre made up of?
It's mainly made up of cellulose from plant cell walls.
50
What properties of fibre make it unique in digestion?
Humans cannot digest fibre.
51
Why is fibre important for our diet if we cannot digest it?
It helps food pass from the gut and prevents constipation.
52
Mention some food products which are rich in fibre.
Whole meal bread, bran, cereals, fresh fruit and vegetables.
53
How much of the human body mass, is actually water?
About one third of our total mass.
54
Is water an inorganic substance or an organic substance?
It's an inorganic substance, and it's chemical formula is H2O.
55
Why is water important for animals?
It gives support to aquatic life.
Gametes travel in watery medium.
Sweating has a cooling effect on the body.
Urine and tears are mainly made up of water.
In the joints water reduces friction when bones move.
Blood is also partially made up of water.
56
Why is water important for plants?
It makes leaves turgid.
Guard cells move by osmosis.
It is needed for photosynthesis.
Some seeds germinate with the help of water.
57
What is nutrition?
It is the process by which an organism obtains food so that it can be broken down by a process called digestion to obtain energy for body processes.
58
There are 2 ways in which living organisms can feed. Please mention both.
Heterotrophic nutrition: search for ready made food. (Holozoic)
Autotrophic nutrition: build up the food themselves. (Holophytic)
59
There are various forms of heterotrophic nutrition, mention all of them below, give examples with each different type.
Herbivores: Feed exclusively on plants. Eg; Rabbits and Sheep.
Carnivores: Feed exclusively on meat. Eg; Hedgehogs and Geckos.
Omnivores: Feed on both plants and meat. Eg; Humans.
Saprophytes: Feed on dead and decay matter. Eg; Fungi & Bacteria.
Parasites: Derives nutrients from host, while it's still alive. Eg; tapeworms.
Mutualism: An association between 2 organism from which they both gain some benefit. One of them usually gets food from the other. Eg: Oxpecker and Zebra.
Commensalism: An association between 2 organism from which one benefits while the other gains nothing but is not harmed. Eg: Fish living close to sharks, to get any scraps of food while the shark is eating.
60
What are the 5 stages of holozoic nutrition?
1. Ingestion.
2. Digestion.
3. Absorption.
4. Assimilation.
5. Egestion.
61
What happens during ingestion?
The intake of food into a cavity (mouth) within the body.
62
What happens during digestion?
Involves the breaking down of food into simple soluble molecules.
63
What is absorption, when it comes to nutrition?
The small soluble molecules are absorbed into the body across a cell membrane.
64
What occurs during assimilation?
The uptake and use of soluble food substances by cells in the body.
65
What happens during egestion?
The removal of indigestible food from the body.
66
In humans what does food consist of?
Carbohydrates, proteins, lipids, mineral salts, vitamins, fibre and water.
67
Once food is placed into your mouth, 2 types of digestion takes place. What are they called?
Chemical digestion takes place due to enzymes, while Mechanical digestion is due to the chewing with the teeth.
(mechanically breaking food down)
68
How are carbohydrates broken down? And what are they broken down into?
They are broken down to monosaccharides by means of amylase enzymes.
69
What are proteins broken down into? Which enzyme is used to for this?
Proteins are broken down to amino acids, with the help of protease enzymes.
70
What do lipids need in order to broken down? What do they break into?
Lipids are broken down into fatty acids and glycerol by means of lipase enzymes.
71
Do mineral salts, vitamins and water need to be broken down?
There is no need for these to be digested, they can be easily absorbed.
72
What happens to food in your mouth?
Food is ingested and mixed with saliva. Which is produced by 3 salivary glands located underneath the tongue.
73
What enzyme is found in saliva?
Enzyme amylase, which converts starch into maltose.
74
What pH does salivary amylase work best in?
In an alkaline pH.
75
What else does saliva help with? Other than providing enzyme amylase.
It helps lubricate the food, and stick small pieces together to form a food bolus, due to the fact that it contains mucus.
76
What are the teeth's primary function?
They prepare the food for digestion by chewing (mastication).
77
What is mastication?
Chewing food, it breaks down tough connective tissue and fibres and helps saturate these materials with lubricants and enzymes.
78
There are 3 parts to a tooth, name them.
The crown, neck and root.
79
What does the crown of a tooth consist of?
It's the white part which can be seen.
It's covered by a layer of enamel which consists of calcium phosphate. Hence why adequate amounts of calcium, phosphate and vitamin D are essential during childhood in order to form a resistant enamel coat.
80
What is the neck of the tooth?
The boundary between the root and the crown.
81
What does the root contain?
Consists of a layer of dentin, that extends up into the crown, the pulp cavity which contains the root canal, nerves and blood vessels.
82
What is dentine similar to?
It is a mineralised matrix similar to the bone, except it does not contain living cells.
83
What does the pulp cavity do?
It receives blood vessels and nerves via the root canal at the base if the tooth, which sits on a bony socket called an alveolus.
84
What are collagen fibres?
They form part of the periodontal ligament extended from the dentin of the root to the surrounding bone. A layer of cementum covers the dentin of the root, providing protection and firmly anchoring the periodontal ligament.
85
What is cementum?
It also resembles bone, but it is softer.
86
There are 4 types of adult teeth, each with specific functions. Please mention them below.
Incisors: Blade-shaped, found at the front of the mouth, useful for clipping and cutting off bits of food.
Canines: Cone shaped with a pointed tip. Useful for tearing or slashing food that is not totally separated yet.
Premolars: Have broad crowns used to grind and crush food.
Molars: Flattened crowns with prominent edges. Useful for crushing, mashing and grinding food, thus preparing for the digestive process.
87
What happens in the oesophagus?
Once the food forms a bolus, the food is swallowed down the oesophagus. Which has circular muscles in the wall, that contracts and squeezes food down.
88
What is the wave like movement, which the oesophagus does when swallowing food, called?
Peristalsis.
89
What is the stomach?
It's a muscular bad that holds up to 2 litres of food.
90
What's the stomachs main function?
Mainly, it stores food and turns it into a liquid called chyme, which is releases in small quantities to the rest of the gut.
91
What does the pyloric sphincter do?
It is a ring of muscle at the lower end of the stomach, which opens to let liquid food pass into the duodenum.
92
What is the first part of the small intestine called?
Duodenum.
93
The stomach contains a certain type of glands. What are they?
Gastric glands, which produce gastric juice.
94
What is Gastric juice made up of?
Pepsin: An enzyme which converts proteins into polypeptides.
Hydrochloric acid: Kills any bacteria that enters the stomach and provides the ideal pH for pepsin to work.
Mucus: Protects the stomach wall against self-digestion.
95
The duodenum receives 3 important secretions. What are they?
Bile salts, pancreatic juices and intestinal juices.
96
Explain why bile salts are needed in digestion.
They are produced by the liver and stored and secreted by the gall bladder.
It's a greenish fluid that emulsifies fat into tiny droplets so that there is an increase in surface area for the enzyme action.
It contains no enzymes, it's an alkaline and it neutralises the acids from the stomach.
97
What are pancreatic juices? And what are they used for?
They are produced by the pancreas. It also contains sodium hydrogen carbonate which neutralises acids from the stomach.
Also have 3 different enzymes which work on 3 different food groups:
Trypsin: Acts on proteins and peptides to form amino acids.
Pancreatic Amylase: Works on starch to convert into maltose.
Lipases: Converts fats into fatty acids and glycerol.
98
Where is the intestinal juices produced and what are they composed of?
They are produced by the intestinal wall, shockingly. Also contains:
Peptidases: Converts peptides into amino acids.
Lipase: Converts lipids into fatty acids and glycerol.
Maltase: Converts maltose into glucose.
Sucrase: Convert sucrose into glucose and fructose.
Lactase: Converts lactose into glucose and galactose.
99
What is the livers main function?
It is responsible for filtration of all incoming foods and fluids.
The body relies on the liver to remove toxins, so that nutrients supplied to the body are capable of nourishment.
100
Mention a few functions which the liver has.
It metabolises proteins, fats and carbohydrates, thus proving energy.
Stores vitamins, minerals and sugars.
Filters the blood and helps remove harmful chemical and bacteria.
Creates bile which emulsifies fats.
Helps to maintain blood pressure.
Breaks down and eliminates excess hormones.
101
What is the second segment of the small intestine called.
Jejunum
102
What is the last segment of the small intestine called?
Ileum.
103
What happens in the ileum?
The end products of digestion are absorbed by the lining, through the process of diffusion and active transport.
104
What does the epithelium in a villus do?
It takes up amino acids, sugars and salts, which it then passes through the wall of capillaries in the villus and into the blood stream.
105
What happens to the fatty acids and glycerol once absorbed?
They are combined to form fat and enter the lympathic system called lacteal.
106
Why is the small intestine adapted for absorption? What properties give it this feature?
It's very long so absorption takes place efficiently due to the large absorbing surface area.
It's surface area is increased again, thanks to millions of small finger-like structures called villi. Each one, has smaller villi on it which are called microvilli.
Has a thin epithelium so fluids can easily pass through it.
Has a good blood supply so that fluids are quickly carried away.
107
What happens to the food that has been absorbed?
The food that has been absorbed by the ileum, is assimilated by the liver.
108
Why is food so important?
It is used for energy, building of tissues, bones and muscles.
109
What happens if excess food is taken in?
It is either stored of denominated depending on the foods nutrient value.
110
What is glucose used for and how is it stored?
It is used in cellular respiration to provide energy for body processes.
Excess glucose is converted into glycogen in the liver by the hormone insulin. Some is stored in the liver and the rest in muscle. Excess glucose is converted into fat.
111
What are amino acids used for and how are they stored?
They are used to build proteins, which could be used as plasma proteins in the blood, to form enzymes or build up cell membranes.
Excess amino acids are not stored but deaminated by the liver. It's by products are urea and glycogen. The urea is excreted while the glycogen is temporarily stored in the liver.
112
What are fats used for and how are they stored?
They are used to build up cell membranes and other cell structures. Also used to provide energy and as a long term store of energy.
Extra fat is deposited as adipose tissue around the abdomen, around the kidney and under the skin.
113
What happens in the finally stage of nutrition, egestion? Which occurs in the large intestine.
Food and materials which are not digested such as cellulose, vegetable fibres, dead cells and mucus arrive in the large intestine.
Here absorption of water and active uptake of mineral salts occur.
114
Where is reaches stored temporarily?
It's stored in the rectum, and then is expelled from the anus.
This is called egestion.
