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Biology Igcse > B6 > Flashcards

B6 Flashcards

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1
Q

What is a balanced diet? What does it contain?

A

A balanced diet contains all seven types of nutrients in the correct amounts and proportions

Carbohydrates
Proteins
Fats
Vitamins
Minerals
Fibers
Water

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2
Q

What is the dietary importance and main source of: carbohydrates

A

Main source:
Bread, pasta, potato, cereal, flour

Uses:
- Glucose travels to cells to release energy for metabolic reactions (17j/kg)
- Respiration/chemical reactions in cells
- extra carbs -> fats that are sorted in hips, legs and stomach to use later

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3
Q

What is the dietary importance and main source of: fats

A

Main source:
Butter margarine, oil, milk, cheese, meat, avocado, egg yolk

Uses:
‘Emergency’ energy source
Stores energy (39J/kg)
Insulation
Makes cell membranes

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4
Q

What is the dietary importance and main source of: proteins

A

Main source:
Meat, fish, eggs, beans, lentils, soy, cheese, milk

Uses:
Making cells
Repairing cells
Enzymes
Haemoglobin, keratin, etc.

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5
Q

What is the dietary importance and main source of: vitamins (limited to C and D)

A

VITAMIN C
Main source:
Citrus, raw vegetables

Uses:
Gum and tooth health
Collagen
Tissue repair

VITAMIN D:
Main sources:
Milk, butter, egg yolk, sunlight

Uses:
Helps calcium be absorbed
Strong bones and teeth

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6
Q

What is the dietary importance and main source of: minerals (limited to calcium and iron)

A

CALCIUM:
Main sources:
Milk/dairy in general, green leafy vegetables, bread

Uses:
Strong bones and teeth
Blood clotting
Healthy muscles

IRON;
Main sources:
Liver, red meat, egg yolk, dark leafy vegetables, beans, nuts

Uses:
Making haemoglobin

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7
Q

What is the dietary importance and main source of: fiber (roughage)

A

Main sources:
Plants, fruits, vegetables, brans of grains, whole meal bread, beans, nuts, brown rice

Uses:
Slows digestion -> we feel full
Absorbs water in bowels
Softens stool
Helps digestive system produce good bacteria
Makes digestive muscle do work so they move food

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8
Q

What is the dietary importance and main source of: water

A

Main source:
Water

Uses:
Solvent -> all chemicals reactions in the body
Dissolves + transport nutrients
Regulates temp
Protects organs
Maintains blood pressure

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9
Q

How does age, gender or pregnancy affect dietary needs?

A

AGE:
Children need less energy/food (small size)
Adults need more energy/food
Teenagers need even more energy/food (period of fast growth)

GENDER:
Males need more energy/food than females

Pregnant/breastfeeding women:
More energy to ensure enough calcium and iron for the baby

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10
Q

What causes malnutrition?

A

Not eating a balanced diet

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11
Q

What causes starvation?

A

If not enough food is eaten for the body to function, there is a chance you may die from starvation

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12
Q

What causes constipation?

A

Not enough fiber in you diet softens your stool too much

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13
Q

What causes coronary heart disease?

A

Fat in animal food -> saturated fat

Fat deposits build on the inside of arteries -> makes them stiffer and narrower

If it happens to coronary arteries -> not enough blood to the heart -> heart doesn’t have enough oxygen -> can’t work properly

If it becomes a blood clot -> heart attack

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14
Q

What causes obesity?

A

When you take in more energy that you use and it is stored as fat

Too much fat -> obese
Higher risk of heart disease, stroke, diabetes

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15
Q

What causes scurvy?

A

A deficiency in vitamin C

Causes bleeding gums, pain in joints + muscles, anaemia (decrease in red blood cells), swelling, exhaustion

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16
Q

What causes rickets?

A

A deficiency in vitamin D

Softer and therefore deformed bones, delayed growth, pain in spine/pelvis/legs, muscle weakness

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17
Q

What causes anaemia?

A

A deficiency in iron can cause for there to not be enough red blood cells, so tissue cannot get enough oxygen -> fatigue

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18
Q

What causes kwashiorkor?

A

Lack of protein

Underweight but having a large belly
Infections
Failure to grow muscle mass
Loss of muscle mass

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19
Q

What causes marasmus?

A

Severe shortage of protein and energy

Lack of calories
Cannot maintain normal body functions
Looking wasted and emaciated

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20
Q

Define ingestion

A

Taking substance into the body through the mouth

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21
Q

Define digestion

A

The breakdown of large, insoluble food molecules into small water soluble molecules using chemical and mechanical processes

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22
Q

Define mechanical digestion

A

The breakdown of food into smaller pieces without chemical change to the food molecule to that the food can fit through the digestive system

23
Q

Define chemical digestion

A

Breakdown of large insoluble molecules into small soluble molecules

Breaking chemical bonds so that useful chemicals can be released and dissolved in the bloodstream

24
Q

Define absorption

A

The movement of digested food through the walls of the intestines -> blood

25
Q

Define assimilation

A

The movement of digested food molecules into the cells of the body where they are used

26
Q

Define egestion (also called elimination)

A

Passing out of food that has not been digested as faeces through the anus

27
Q

What is the alimentary canal?

A

Part of the digestive system that food travels through

28
Q

Identify the organs of the digestive system

A

Mouth (teeth, tongue, salivary glands)
Pharynx
Epiglottis
Esophagus
Stomach
Liver
Gallbladder
Pancreas
Large/small intestines
Appendix
Rectum
Anus

29
Q

What is the function of the: Mouth

A

Ingestion

Physical digestion (teeth)
Chemical digestion (salivary glands -> saliva (made of water, mucus,amylase (carbohydrase)))

Tongue rolls food into bolus -> slides down esophagus (mucus)

30
Q

What is the function of the: pharynx

A

Region at the back of the throat where the trachea and esophagus divide

31
Q

What is the function of the: epiglottis

A

Flap of tissue at the back of the throat that prevents food from entering the lungs

32
Q

What is the function of the: esophagus

A

Tube that connects the mouth to the stomach

Peristalsis -> movement of muscles to move food

33
Q

What is a sphincter

A

Muscles that stay contracted until substances need to pass through (one between esophagus and one at anus)

34
Q

What is the function of the: stomach

A

Hydrochloric acid -> attacks the bad bacteria (microbes)

Protease enzymes (pepsin) -> chemically digest proteins -> amino acids, functions at high acidities

Muscles -> contract and relax to grind and mix the food inside stomaching -> churning

Mucus -> protect the stomach from acid by producing a lining

Gastric juice -> HCl + mucus + food and enzyme solution

35
Q

What is the function of the: small intestine

A

Small soluble food molecules are absorbed into the bloodstream
To do this it has:
Large surface area
Thin wall
Good blood supply
(Also it has a smaller diameter but is longer than the large intestine)

2 substances secreted into the duodenum (start of small intestine) for protection against gastric juices:
Mucus -> lining
Bile -> neutralises acid and emulsifies fat (physically digest to make higher surface area)

36
Q

How are the 3 food types digested in the small intestine?

A

Carbohydrates:
Carbohydrase secreted by pancreas into duodenum -> breaks bonds to makes simple sugars

Proteins:
Trypsin (protease) is secreted by pancreas into duodenum -> breaks bonds to make animo acids

Lipids/fats:
After emulsification -> lipase secreted from pancreas into duodenum -> bonds break and make fatty acids and glycerol

Simple products then absorbed into bloodstream in the ileum (second part of small intestine)

37
Q

What is the function of the: vili in the small intestine

A

Vili -> bumps on the surface of the small intestine
Helps with absorption

Walls are one cell thick (fast diffusion)
Each has capillaries (blood can absorb the simple molecules quickly)
Bump structure -> more surface area

38
Q

What is the function of the: large intestine

A

To absorb excess water that is mixed with the waste food to prevent dehydration

39
Q

What is the function of the: rectum and anus

A

Rectum store faeces
Anus blocked by sphincter
Relax -> faeces passes out through egestion

40
Q

Identify the types of human teeth

A

Look at diagram

Central incisors (front teeth)
Latent incisors
Canine
1st premolar
2nd premolar
1st molar
2nd molar
3rd molar

41
Q

Describe the structure of human teeth

A

Crown (the part that sticks out)
Neck (the ‘transition point’ from out -> in the gums)
Root -> in the gums

Enamel (outer layer)
Cement (outer layer in gums)
Dentine (under enamel and cement)
Gum

42
Q

What are the functions of the different types of teeth?

A

Canine:
Sharp and pointed teeth -> bite and tear food

Incisors:
Small rectangular shaped teeth -> cutting food

Premolars:
Behind canines -> grind soft food

Molars:
Behind premolars -> grind hard food

43
Q

How does plaque and tartar form the teeth?

A

Bacteria mixes with saliva and forms a sticky film

First called plaque (is easy to remove (brush your teeth))

Later hardens into tartar (which cannot be removed by brushing)

44
Q

How is a cavity formed?

A

The bacteria in the plaque can feed off of the sugar

Use it in respiration and turns it into acid which dissolves the enamel makes its way into the dentine, which could cause a cavity

45
Q

What are way to prevent cavities?

A
  1. Moderate sugar intake -> teeth will be less at risk for cavities (at most 2 per day with meals)
  2. Brush your teeth at least x2 a day with fluoride toothpaste which make teeth more resistant to decay
    -> regular brushing removes plaque and prevents gum disease/decay
  3. Make regular dentist visits
46
Q

What is the function and production place of: carbohydrase

A

Production:
Amylase -> In mouth in salivary glands
Other carbohydrase -> In pancreas and used in small intestines

Function:
Break bonds in carbohydrates -> starch -> simple sugars

47
Q

What is the function and production place of: protease

A

Production:
Pepsin -> stomach (made to work in high acidity)
Trypsin-> made in pancreas, works in small intestine

Function:
Chemically breaks bonds in protein -> amino acids

48
Q

What is the function and production place of: lipase

A

Production:
Pancreas and small intestine (works in small intestine)

Function:
Chemically breaks down fats/lipids into fatty acids and glycerol

49
Q

What is the function of hydrochloric acid in the stomach?

A

Attack microbes that may have accidentally swallowed

Gives low pH (high acidity) for pepsin to work in

50
Q

Why is the low pH of hydrochloric acid so important?

A

Denatures harmful microorganisms in food

Gives optimum pH for protease activity

51
Q

What is the function of bile?

A

Bile -> alkaline
Neutralises the acid from gastric juices so that the walls of the small intestine are protected and other enzymes can work at their optimum

52
Q

How does bile contribute to the digestion of fat?

A

Bile emulsifies fat

Separates it into small pieces and evenly distributed it among the enzymes

Creates a larger surface area for lipase to digest

53
Q

Describe the structure of a villus

A

Use diagram from notes
(Outside -> inside)

Cell lining
Lacteal
Capillary

Blood approaches one side and leaves on the other

54
Q

What do capillaries and lacteals do in villi?

A

Lacteal -> main route drainage of glycerol and fatty acids in the form of lymph -> returns to systemic circulation via thoracic duct

Capillaries -> absorb small molecules (amino acids and simples sugars) and sends them to the liver

Biology Igcse (11 decks)

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