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Science Year 2 > Nutrition in humans > Flashcards

Nutrition in humans Flashcards

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1
Q

What are the five stages of nutrition?

A

Ingestion, digestion, absorption, assimilation ands egestion

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2
Q

What is ingestion?

A

Food is taken into the body via the mouth.

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3
Q

What is digestion?

A

Large, complex food molecules are broken down into small, simple molecules. Includes both physical/mechanical and chemical/enzymatic digestion.

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4
Q

What is absorption?

A

Digested food substances e.g. glucose, amino acids, fatty acids and glycerol, pass through the plasma membrane of epithelial cell lining the small intestine by diffusion and active transport.

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5
Q

What is assimilation?

A

Absorbed food substances are transported in the bloodstream to all parts of the body, where they are utilised by cells to make new protoplasm or broken down to release energy.

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6
Q

What is egestion?

A

Undigested food e.g. dietary fibre is passed out of the body via the anus

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7
Q

The human digestive system consists of the ____ and its___.

A

The human digestive system consists of the alimentary canal and its associated organs.

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8
Q

The organs in the alimentary canal include.

A

Mouth, oesophagus, stomach, small intestines, large intestines and anus

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9
Q

What are the associated organs?

A

Tongue, teeth, salivary glands, Pancreas, liver, gallbladder, (including bile duct according to Gemini)

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10
Q

What is another fancy term for the mouth?

A

Buccal Cavity

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11
Q

What is associated organs?

A

Associated organs are organs that help with digestion, but are not part of the alimentary canal.

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12
Q

Describe the physical/mechanical digestion that is in the mouth.

A

Chewing action of teeth breaks down food into smaller pieces (physical digestion) to increase surface area to volume ratio for more efficient chemical digestion.
Chemical digestion……
Tongue rolls food into a bolus before pushing it into the pharynx (throat) and down the oesphagus.

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13
Q

Describe the chemical digestion that is in the mouth.

A

Salivary glands secretes saliva, which helps to moisten and chemically digest food. Saliva contains the enzyme salivary amylase which catalyses the breakdown of starch into maltose.

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14
Q

What are the two stages of nutrition that takes place in the mouth?

A

Food enters the body through the mouth by ingestion.
Digestion of food begins in the mouth.

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15
Q

Are there chemical digestion and physical digestion in the oesophagus? Explain.

A

There is both physical and chemical digestion in the oesophagus. Peristalsis aids in the physical digestion of food, while there are very little/negligible chemical digestion that takes place as the saliva is still mixing with the food in the oesophagus.

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16
Q

Describe what the oesophagus is and what feature it has to aid in physical digestion. Explain further.

A

Oesophagus is a muscular tube that channels food to the stomach. The wall off the oesophagus is made up of two layers of smooth muscles. Longitudinal muscles (outer layer) and circular muscles (inner layer). Alternate contractions and relaxations of smooth muscles produce a rhythmic, wave-like motion called peristalsis.

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17
Q

What are the functions of peristalsis in the digestive system?

A

Peristalsis moves the food/ boli along the oesophagus.
Mixes food with saliva digestive juices.
Aids in physical digestion of food

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18
Q

Do chemical and physical digestion occur in the stomach? Explain.

A

Yes. Muscular walls churn (peristalsis) the food (physical digestion) Secretes gastric juice, which contains: Hydrochloric acid -> to kill bacteria/microorganisms -> Provides the optimum acidic pH (around 2) for protease to work. Gastric protease (pepsin) which catalyses the breakdown of proteins into polypeptides.

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19
Q

What is a stomach?

A

A stomach is a muscular organ which stores food temporarily for 2 to 6 hours.

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20
Q

The resultant partially digested, semi-liquid food in the stomach is called_____.

A

Chyme

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21
Q

Does the pancreas have chemical digestion and physical digestion?

A

The pancreas have chemical digestion primarily and does not have physical digestion.

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22
Q

Describe what the pancreas does.

A

Pancreas secretes pancreatic juice to digest food in the small intestine. Pancreatic juice has an alkaline pH (around 8) to neutralise the acidic chyme to provide the optimum pH for pancreatic and intestinal enzymes to work. Contains the enzymes pancreatic amylase, pancreatic protease (trypsin) and pancreatic lipase.

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23
Q

What is the relationship between the liver, gallbladder and bile duct?

A

The liver produces bile, which is stored in the gallbladder until it is ready to be released into the small intestines via the bile duct.

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24
Q

Bile has a pH of ____ to _____.

A

Bile has an alkaline pH (around 8) to neutralise the acidic chyme.

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25
Q

Bile is/is not an enzyme.

A

Bile is not an enzyme.

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26
Q

Bile is released into the ____. Bile ___ in bile _____ fats, ……….

A

Bile is released into the small intestine through the gallbladder. Bile salts in bile emulsifies fats, breaking up large fat globules into small droplets (physical digestion), to increase its surface area to volume ratio for more efficient lipase-catalyses digestion. (making it easier for pancreatic lipase (an enzyme from pancreatic juice) to further break down the fats into fatty acids and glycerol.)

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27
Q

Chyme passes from the stomach into the ______.

A

Chyme passes from the stomach into the small intestine.

28
Q

The small intestine secretes ___ to digest food.

A

The small intestine secretes intestinal juice to digest food.

29
Q

Describe more about the intestinal juice.

A

Intestinal juice has an alkaline pH of around 8 to neutralise the acidic chyme. It contains the enzymes intestinal maltase, intestinal lactase, intestinal sucrase, intestinal protease (peptidase) and intestinal lipase.

30
Q

Identify and explain the role of two key hormones in the regulation of blood glucose concentration

A

Insulin: Produced by the pancreas, insulin lowers blood glucose levels by facilitating the uptake of glucose into cells (especially muscle, fat, and liver cells). It encourages glucose storage as glycogen in the liver and reduces the release of glucose into the bloodstream.

  • Glucagon: Also produced by the pancreas, glucagon raises blood glucose levels by signaling the liver to break down stored glycogen into glucose, releasing it into the bloodstream.

These hormones help to regulate the concentration of glucose in the blood, keeping it relatively stable at 90mg per 100cm cube of blood.

31
Q

What is a diabetes?

A

Diabetes is a medical condition in which blood glucose levels remain persistently higher than normal.

32
Q

What is type 2 diabetes?

A

Type 2 diabetes is a chronic medical condition where glucose builds up in the bloodstream as insulin produced to lower blood glucose level is either INSUFFICIENT or NOT EFFECTIVE (insulin resistance)

33
Q

What plays a role in type 2 diabetes?

A

Both lifestyle and genes

34
Q

What should we do in order to prevent or control Type 2 Diabetes?

A

We should eat healthily, be physically active, and avoid excessive weight gain.

35
Q

What about the age group of people who get Type 2 Diabetes?

A

Type 2 Diabetes occurs more frequently in people over 40 years old, particularly those who are overweight and physically inactive. However, in recent times, younger adults and children have also been developing type 2 diabetes.

36
Q

Which description of the human large intestine is not correct?
A absorbs most of the water in the gastrointestinal tract
B absorbs vitamins and mineral salts
C does not secrete any digestive enzymes
D temporarily stores undigested plant and animal matter

A

A is the answer.
Large intestine main function is to absorb water and mineral salts. However, small intestine is longer, hence already absorbed most of the water via osmosis.

37
Q

What is the last stage of nutrition?

A

Egestion not excretion

38
Q

What are the two processes for digested food molecules to be absorbed in the small intestine?

A

Diffusion and active transport

39
Q

What are the stages of nutrition in the small intestine?

A

Digestion first followed by absorption

40
Q

What is/are absorbed into the epithelial cells and then transported away by the capillaries in the small intestine?

A

Glucose and amino acids.

41
Q

What is/are absorbed into the epithelial cells and then transported away by the lacteals?

A

Fatty acids and glycerol are absorbed into the epithelial cells where they are converted into fats before they are transported away by the lacteals.

42
Q

What are the adaptations of the small intestine for absorption?

A
  1. It is long (approximately 7m) to increase time for absorption, making the absorption of nutrients more efficient.
  2. The inner wall of the small intestine has many folds. On the folds are many finger-like projections called villi, The outermost layer of the villi is lined with a single layer of epithelial cells with microvilli structures on them.
    The folds, villi and microvilli greatly increase surface area to volume ratio for higher rate of absorption of digested food into the epithelial cell.
  3. this one-cell-thick epithelial layer allows a shorter distance for diffusion of digested food substances into the cells.
  4. Digested food molecules are rapidly transported away by the body’s transport system after absorption to maintain concentration gradient for diffusion.
43
Q

Is rectum not part of the alimentary canal and its associated organs?

A

The rectum is part of the alimentary canal. This is because large intestine is made up of colon and rectum.

44
Q

What is the difference between the rectum and the anus?

A

The anus is where the faeces exits while the rectum stores undigested food.

45
Q

Is boli the same thing as bolus?

A

Boli— singular
Bolus— plural

46
Q

What is pepsin?

A

Gastric protease

47
Q

What is trypsin?

A

Pancreatic protease

48
Q

What is peptidase?

A

Intestinal protease

49
Q

Is the production of bile in the liver a chemical digestion?

A

No, it is not a digestion when something is produced.

50
Q

Are there physical and chemical digestion in the gallbladder, bile duct and the liver?

A

No. This is because no food passes the gallbladder, bile duct and the liver.

51
Q

Why is the small intestine long (approximately 7m)?

A

It is to increase time for absorption and to absorb more digested food molecules.

52
Q

In the oesophagus, is there chemical digestion and physical digestion?

A

There is little chemical digestion due to the salivary amylase. However, there is no physical digestion as the peristalsis does not really break the food into smaller pieces.

53
Q

In the pancreas, it secretes pancreatic juice, but does it count as chemical digestion? No physical digestion right?

A

No. Since food does not go through the pancreas.

54
Q

Which part of the alimentary canal has the most amount of digestion?

A

Small intestine
(Starch, Fats etc)

55
Q

Is stomach rank the second for the most amount of digestion?

A

It is arguable as it depends on the amount of protein that is digested into polypeptides in the stomach and the amount of proteins that is passed on to the small intestine that is further digested.

56
Q

Strips of photographic film covered with a layer of protein were placed in various solutions. Removal of the protein makes the film clear and transparent. In which solution would the photographic film become clear?
A gastric protease and hydrochloric acid
B gastric protease and sodium hydroxide
C pancreatic protease and hydrochloric acid
D pancreatic protease and sodium hydroxide

A

A
This question is testing your understanding of the pH of different substances. Gastric protease has a pH of 2 and hydrochloric acid has a pH of 1-3, thus it has an environment that is optimum for its pH, allowing a faster reaction of the enzyme with the substrate.

This leaves B and C to be incorrect.
Option D is incorrect as pancreatic protease has a pH of 8 while sodium hydroxide has a pH of 12-14, so it is not an optimum pH environment.

57
Q

Which of the following can pass through the placenta?
A nicotine (yes), white blood cells (yes), gonorrhoea bacteria (yes)
B nicotine (yes), white blood cells (yes), gonorrhoea bacteria (no)
C nicotine (yes), white blood cells (no), gonorrhoea bacteria (no)
D nicotine (no), white blood cells (yes), gonorrhoea bacteria (yes)

A

C
Although nicotine is not taught, you can look at the gonorrhoea bacteria and the white blood cells to get the answer. White blood cells cannot pass through the placenta since there is no direct blood contact.

58
Q

Explain how physical and chemical digestion work together to ensure efficient digestion of nutrients.

A

Physical digestion breaks down food into smaller pieces, thus increasing surface area to volume ratio of food that are more exposed to/in contact with digestive juices containing enzymes, which catalyse (speed up) chemical digestion of large food molecules into smaller food molecules that can be absorbed through plasma membrane of epithelial cell by diffusion/active transport.

59
Q

Describe the role of bile in the digestion process.

A

The bile aids in the emulsification of fats as it breaks down large, fat globules into smaller fat droplets, hence providing a larger surface area to volume ratio exposed to digestive juices for more efficient lipase-catalyse fat digestion.

60
Q

Is this accurate, “Bile breaks down large complex fat molecules into smaller, simpler fat molecules.”?

A

No it is not suppose to be complex and simpler. The fat globule (contains many fats) is then split into smaller fats droplets, so the molecule is NOT BROKEN DOWN

61
Q

Which statements are correct?
1 Bile breaks down fat to produce a fatty acid as one of the products of the reaction.
2 Digestion of fats only begins in the small intestine.
3 The pancreas is part of the alimentary canal.

A 2 only
B 3 only
C 1 and 2 only
D 1 and 3 only

A

A
Bile does not chemically digest fat. Each molecule would not break up. Through emulsification, the large fat globule would only become smaller fat droplets.

62
Q

Which characteristic of the small intestine is not correctly linked to its purpose?
A amino acids transported away from blood capillaries (characteristics) maintain concentration gradient for active transport (purpose)
B epithelium layer is one-cell thick (characteristic) faster diffusion of digested food molecules across the layer (purpose)
C many folds on surface (characteristic) increase surface area to volume ratio for absorption (purpose)
D rich in blood capillaries (characteristic) faster diffusion of glucose into blood capillaries (purpose)

A

A

63
Q

What is the role of the liver in assimilation?

A

The liver processes absorbed nutrients by:
Storing glucose as glycogen
Synthesising plasma proteins from amino acids
Breaking down amino acids to urea for excretion
Storing or converting lipids for energy or membrane synthesis.
(Flashcard by ChatGPT)

Notes:
In the liver
Glucose—> Glycogen—> glucose—> cellular respiration
Amino acids—>urea—> excreted by kidneys
Amino acids—> synthesis of plasma proteins (in the liver)
Amino acids—> synthesis of protoplasm (in cells)

Outside of the liver
Lipids—> synthesis of plasma membrane

64
Q

How is glucose used in the body?

A

Glucose is used in cellular respiration to produce energy (ATP) for cellular activities.

65
Q

What happens to amino acids in the liver?

A

Amino acids are used to synthesise plasma proteins in the liver and other cell proteins for growth, repair and maintenance.

66
Q

What are the role of lipids in the body after assimilation?

A

Lipids are used for building cell membranes. Energy storage when not immediately needed for energy

67
Q

What is urea, and how is it produced?

A

Urea is a waste product formed from the breakdown of amino acids in the liver and is excreted by the kidneys.

Science Year 2 (12 decks)

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