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Biology IGCSE > Chapter #7 - Human Nutrition > Flashcards

Chapter #7 - Human Nutrition Flashcards

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1
Q

What is the defenition of diet?

A

The food an animal eats in one day.

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2
Q

What are the different nutrients humans need?

A
  • Crabohydrates
  • Proteins
  • Fats
  • Vitamines
  • Minerals
  • Water
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3
Q

What does the amount of food you eat depend on?

Only a few examples

A
  • Age
  • Gender
  • Occupation
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4
Q

How does the enrgy of 1 gram of fat compare to the energy in 1 gram of protein or carbohydrates?

A

1 gram of fat contains about twice as much energy as 1 gram of protein or carbohydrates.

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5
Q

Why are humans able live longer without food that without water?

A

Because they have reserves.

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6
Q

What are some examples of foods that contain crabohydrates?

A
  • Rice
  • Pasta
  • Weat/Bread
  • Maiz
  • Sweet foods
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7
Q

What substances is a carbohydrate made of?

A

Starch + Sugar

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8
Q

What are the uses fats and oils in humans?

A
  • For energy.
  • To make cell membrames.
  • Acts as an insulator, reducing heat loss.
  • Can form around organs, physicalyy protecting them.
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9
Q

Where do humans store excess fats and oils?

A

Under skin in adipose tissue (acts as an insulator). It can also form a layer around the body organs, providing mechanical protections for them.

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10
Q

What are some examples of foods that contain fats and oils?

A
  • Avocado
  • Egg
  • Oily fish
  • Olive oil
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11
Q

What is the defenition of adipose tissue?

A

Fat stores under skin.

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12
Q

What are the uses of proteins in humans?

A
  • To build new cells, for growth
  • Can be broken down into amino acids, and than used to make other proteins in body such as hemoglobin, insulin and antibodies.
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13
Q

What is hemoglobin?

A

It is a protein which is useful in the body

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14
Q

What are some examples of foods that contain protein?

A
  • Fish
  • Chicken
  • Eggs
  • Tofu
  • Lentils
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15
Q

What are vitamins?

A

Organic substances which are only neede in samll amounts. If you don’t have enough of the vitamin, you may get a defivency disease.

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16
Q

What foods contain vitaine C?

A

Citrus fruits (organges, limes ect.) and raw vegetables.

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17
Q

Why is vitamine C needed?

A

To make a streachy protein called collagen. It is found in skin and other tissues, it keeps tissue in good repair.

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18
Q

What is the deficiency disease for vitamine C?

A

Scurvy which causes pain in joints and muscles, bleeding from gums & other places. It was a common disease with sailors because they couldn’t have fresh fruits and veggies at sea.

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19
Q

What food contain vitamine D?

A

Butter, egg yolks, but most vitamine D is made by the skin when sunlight falls on it.

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20
Q

Why is vitamine D needed?

A

It helps calcium be absorbed for making bones and teeth.

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21
Q

What is the deficiency disease for vitamine D?

A

Rickets, in which bones becaome soft and deformed.

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22
Q

What is the defenition of minerals?

A

Inorganic substances (only needed in small amounts in our diets).

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23
Q

What are the two minerals we need to know about?

A

Calcium and iron.

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24
Q

What are the two vitamines we need to know about?

A

Vitamine D and vitamine C

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25
Q

What foods contain calcium?

A

Milk and other dairy products.

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26
Q

Why is calcium needed?

A

For bones and teeth; for blood clotting (for scabs).

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27
Q

What is the defficiency disease for calcium?

A

Hypocalcemia causes brittle bones and teeth; poor blood clotting (for scabs).

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28
Q

What foods contain iron?

A

Liver, red meat, egg yolk, dark green veggies.

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29
Q

Why is iron needed?

A

For making hemoglobin, the red pigment in blood which carries oxygen.

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30
Q

What is the defficiency disease for iron?

A

Anemi in which there are not enough red blood cells, tissue do not get enough oxygen.

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31
Q

Why is fibre not digested?

A

Because humans cannot digest cellulose.

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32
Q

Is fibre absorbed?

A

No, it just passes through the digestive system.

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33
Q

What is the purpose of fibre?

A

It keeps digestive system working properly and prevents constipation.

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34
Q

What is peristalsis?

A

Rhthmic muscular contractions that move food through digestive system.

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35
Q

What do hard fiborous foods do?

A

The cause muscles to contract more strongly.

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36
Q

Why is water important for the human body? (5)

A
  • Important solvent in the cytoplasm (site of chemical reaction). So, metabollic reactions cannot happen if cell is dehydrated.
  • Spaces between our cells are a watery liquid.
  • Liquid part of blood (plasma) is mostley water.
  • It is a solvent (the one dissolving the othet substance) for enzymes and nutrienst in the digestive system.
  • Needed to get rid of waste products (e.g. urea in urine)
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37
Q
What are the letters?
A

A= Nasal cavity
B=Palate
C= Bolus of food
D= Tongue
E= Salivary gland
F= Salivery duct
G= Trachea
H= Oseophagus
I= sphincter muscle
J= Liver
K= Stomach
L= Gall bladder
M= Bile duct
N= Sphincter muscle
O= Pancreas
P= Pancreatic duct
Q= Duodenum (small intestine)
R= Ileum (small intestine)
S= Colon (large intestin)
T= Rectum (large intestine)
U= Anus

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38
Q

What is the order of digestion?

A
  1. Ingestion
  2. Digestion
    - Physical
    - Chemical
  3. Absorption
  4. Assimilation
  5. Egestion
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39
Q

What is Ingestion?

A

Taking food and drink into the mouth using the lips, teeth and tongue.

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40
Q

What is physical digestion?

A

Large pices of food are broken down into smaller pices through mechanical means (e.g. chewing) which causes the food to gain surface area. Food than, is able to undergo chemical digestion more effectivley.

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41
Q

What is chemical digestion?

A

Large molecules are broken down into smaller molecules by enzymes. Molecules must be small enough to pass into blood.

42
Q

What is absorption?

A

The movement of small molecules and mineral ions through the walls of the intestione and into the blood (diffusion, active transport).

43
Q

What is assimilation?

A

The nutrients are absorbed by individual cells and used for energy to make individual substances.

44
Q

What is Egestion?

A

The material that we cannot digest (much of it is fiber) remainsin our intestines and eventually passes out as faeces.

45
Q

What is the alimentary canal?

A

A long tube that runs from the mouth to the anus. The wall contains muscles which contract and relax to move food along. This is called peristalsis. The canal is lubricant with mucus so food can slide easily.

46
Q

How is mucus made for the whole canal?

A

By goblet cells.

47
Q

What makes food stay in the canal for a while?

A

Sphincier muscles.

48
Q

what do sphincier muscles do?

A

They keep food in one part of canal for a while.

49
Q

What type of digestion is present in the mouth?

A

Physical and chemical digestion.

50
Q

How does digestion work in the mouth?

A
  • Teeth grind food to increase surface area.
  • Tongue mixes the food with saliva, forming a samll bolus that can be swallowed.
  • Mucus helps food bind together in the bolus.
  • Amalayse begins to digest sarch.
  • Water dissolves substancesin the food, allowing us to taste them.
51
Q

What is the defenition of salivary glands?

A

Make saliva

52
Q
A
53
Q

What is the function of the oesophagus?

A

Takes food down to the stomach. The food goes down the lumen and than the sphincher muscles relax to let food in and control when it is let in.

54
Q

What is the lumen?

A

The center part of a tube in this case (the alimentary canal).

55
Q

What are the features of the stomach?

A
  • It has strong muscular walls which conratract to mix the food with mucus and enzymes.
  • Goblet cells secrete mucus.
  • Some cells produce HCl, others produce enzymes (proteases (pepsin))
  • Store food for 1-2 hours then sphincter muscles open into the duodenum.
  • Has a pH of 2 which helps kill harmful microorganisms in food.
56
Q

What is the purpose of goblet cells in the alimentary canal?

A

To produce mucus which helps food slide along canal more easily.

57
Q

What is the purpose of hydrochloric acid in the stomach?

A
  • Low pH of aprox. 2 kills harmful bacteria
  • Optimum pH for enzymes (proteases)
  • Breaks down food.
58
Q

Where is the place for most protease activity?

A

The stomach.

59
Q

How long is the small intestine?

A

About 5m long.

60
Q

Why is the small intestine called small?

A

Because it is narrow.

61
Q

What are the two parts of the small intestien (in order)?

A
  • Duodenum
  • Ileum
62
Q

What is the purpose of both parts of the small intestine?

What is its job?

A

Duosenum: Digestion
Ileum: where absorption begins

63
Q

Where are both parts of the small intestine located?

A

Duodenum= Firts part, nearest the stomach
Ileum= Last part nearest to colon

64
Q

What are the features of the duodenum

What does it have to help it do its job?

A
  • Pncreatic juice (a fluid made by the pancreas) flows through the pancreatic duct, into the duodenum.
  • Filled with many different enzymes to help with chemical digestion in this part of the canal.
  • Bile flows along bile duct and neutalises acidic contents for stomach.
  • Bile also emulsifies fats.
65
Q

How long is the larg intestine?

A

About 1.5m

66
Q

Where is the large intestine located?

A

The final part of the alimentary canal

67
Q

What are the two parts of the large intestine (in order)?

A
  1. Colon
  2. Rectum
68
Q

What is the purpose of the colon?

A

Absorbs water still left in the food (makes poop harder)

69
Q

What is part of the digestive system but not the amimentary canal?

A

The liver and pancreas.

70
Q

What does the liver produce and why, where is it stored?

A

The liver creates bile (an alkaline) which is stored in the gall bladder. It is then transported to the duodenum where it neutralizes acidic mixtures from the stomach and emulsifies fat. It also works to make enzymes work at a more optimum pH.

71
Q

What does it mean for fat to be emulsified?

A

Big fat droplets => Smaller fat droplets

72
Q

How are vitamines, minerals and water digested?

A

They are already small enough to be absorbed into the blood.

73
Q

How do teeth work?

A

They bite off pices of food. Then, chop, crush or grind pieces into smaller pieces.

74
Q

What does chewing food with teeth do?

A

It gives the food a larger surface area which makes it easire for enzymes to work on food later. It also helps any soluble molecules or ions dissolve in the watery saliva.

75
Q

Draw a labled diagram of a tooth.

A
76
Q

What are the features of the enamel?

A
  • The part above the gum is covered in the enamel.
  • The enamel is the hardest substance in animals.
  • Hard to break/chip, however, they can be dissolved by acid.

In teeth

77
Q

How are teeth dissolved by acid?

A

The bacteria feed on sweet food left on teeth. These bacteria produce acid which dissolve enamel and cause decay.

78
Q

What are the features of the dentine?

A
  • It is under the enamel
  • It is similar to bone
  • Has channels which contain cytoplam
  • Hard but not as hard as enamel

In teeth

79
Q

What are the features of the pulp?

In teeth

A
  • In the middle of the tooth
  • It has nerves and blood vessels
  • Vessels supply the cytoplasm in the dentine with nutrients and oxygen
80
Q

What are the features of the cement?

In teeth

A
  • The part embedded in the gum is covered with cement.
  • The cement has fibres growing out of them
81
Q

What is the purpose of the fibres attached to the cement in the teeth?

A

They attach the tooth to the jaw bone but allow it to move slightly when biting/chewing.

82
Q

What are the different types of teeth?

A
  • Incisor
  • Canine
  • Premolar
  • Molar
83
Q

What are the charectaristics of an incisor?

A
  • Front of mouth
  • Chiseled shaped (sharp edge)
  • Used to bite off pieces of food
84
Q

What are the charectaristics of a canine?

A
  • On either side of incisor
  • Slightly more pointed than incisor
  • Similar function to incisor
85
Q

What are the charectaristics of premolars?

A
  • Behind canine
  • Have 2 points (cusps)
  • Hve 1 or 2 roots
  • Used for tearing and grinding food
86
Q

What are the charectaristics of molars?

A
  • Back of the mouth
  • Have 4 or 5 cusps
  • Hve 2 or 3 roots
  • Used for chewing and grinding food
87
Q

What temp. do the enzymes in the digestive systemwork best?

A

At about 38 degrees celcius (normal body temp.)

88
Q

What are the important enzymes in the digestive systems?

A
  • Amalayse
  • Lipase
  • Maltase
  • Pepsin
  • Trypsin
89
Q

Where is amalayse secreted and where does it act?

A
  • Secreted in salivary glands and pancreas
  • Acts in mouth and duodenum
90
Q

Where does Lipase secrete and where does it act?

A
  • Secreted by paancreas
  • Acts as duodenum
91
Q

Where is maltase secreted and where does it act?

A

It is secreted by cells lining the small intestine and acts in the small intestine. This tissue is called the ephithelium.

92
Q

Where is protease secreted and where does it act?

A

Secreted by the walls of the stomach and pancreas and acts in the stomach and duodenum.

93
Q

What is the relationship between the pancreas and enzymes?

A

Pancreatic juice contains all three enzymes (protease, amalayse, lipase)

94
Q

What is the process of how starch is broken down?

A

Firts broken down by amalayse into maltose, than broken down to glucose by maltase.

95
Q

What are the charectaristics of pepsin

Where it is secreted, what is its optimum pH

A
  • Secreted from the stomach walls in a liquid called gastric juice (stomach walls secrete this liquid which contains pepsin and HCl).
  • Has an optimum pH of 2, so its perfectly suited to working in the stomach’s very acidic conditions.
96
Q

What are the charectaristics of trypsin?

Where it is secreted, what is its optimum pH

A
  • It is created in the pancreas and secreted into the duodenum
  • Optimum pH of 7. this means acidic contents of the stomach must be neutralised by alkaline bile and pancreatic juice.
97
Q

What do enzymes break fats into?

A

Glycerol and fatty acids

98
Q

What is the defenition of villi?

A

Small finger-like projections that line the inner surface of the small intestine, increasing its surface area.

99
Q

What happens in the microvilli?

A
  • Where maltase acts to break down maltose into glucose
  • Where glucose, amino acids and more nutrients are absorbed into the blood
  • Most of the nutrients pass into blood capillaries inside the villus.
  • These capillaries from all villi join a vein called the hepatic portal vein which sends everything to the liver.
  • The liver cells absorb and assimilate the substances
  • Glucose may be stored as glycogen
  • Amino acids are used to make different proteins
  • If there are more amino acids than needed, they will be broken down into urea and excreted.
100
Q

What are the defenitions of lacteals?

A

Small vessels that absorb fatty acids and glycerol in the small intestine. There conntents are eventually emptied into blood.

101
Q

What is the defenition of assimilation?

A

To take nutrients that have been absorbed and make something out of them.

102
Q

What is the general purpose of villi and micro villi?

A

To increase the surface area of the small intestine so that more nitrients can be absorbed in the same distance.

Biology IGCSE (16 decks)

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