Digestion Flashcards

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1
Q

What are three biochemical reactions?

A
  1. Metabolism
  2. Catabolism
  3. Anabolism
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2
Q

What does metabolism refer to?

A

All chemical reactions in a cell

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3
Q

What does catabolism refer to?

A

The breakdown of complex chemical structures to simpler molecules

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4
Q

What does anabolism refer to?

A

Combining simple molecules into complex structures

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5
Q

What are macronutrients?

A
  • Any nutrient required in large amounts
  • Generally used as a source of energy
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6
Q

What are micronutrients?

A
  • Any nutrient required in small amounts
  • Can’t be used for energy
  • Essential and play a unique role in the body
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7
Q

What are essential nutrients?

A

Nutrients which can’t be produced by the body and therefore must come from an external source (ex. food)

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8
Q

What are non-essential nutrients?

A

Nutrients that are still necessary, but can be produced by the body if lacking in diet

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9
Q

What is an enzyme?

A

A protein molecule that acts as a catalyst to increase the rate of a chemical reaction

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10
Q

Fill in the blanks:

Each type of enzyme has a specific ________ & ___________ which will only fit one type of ____________

A

SHAPE, ORIENTATION and SUBSTRATE

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11
Q

What is the optimal temperature for enzymes in the human body?

A

Approximately 37°C

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12
Q

What is the optimal pH range for most enzymes in the human body?

A

pH 6 - 8

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13
Q

What kind of environment do stomach enzymes prefer?

A

They work best in acidic conditions

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14
Q

What does an inhibitor do to an enzyme?

A

Attach to an enzyme and reduces its ability to bind substrates

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15
Q

Are vitamins and minerals macromolecules?

A

No, they are essential nutrients, but are only required in small amounts

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16
Q

What are vitamins?

A
  • Organic compounds that act as coenzymes
  • Function in tissue growth, development, and immunity

(ex. Vitamin C)

17
Q

What are minerals?

A
  • Inorganic compounds
  • Play an important role in bone and cartilage structure
  • Essential components of hormones, enzymes, vitamins, and hemoglobin

(ex. Magnesium)

18
Q

How are reactions sped up?

A

By introducing a catalyst, which lowers the amount of energy required, without being used up in the reaction

19
Q

What role does the digestive system play in the body?

A

Physically and chemically breaks down food in order to absorb nutrients into the bloodstream

20
Q

What are the 5 main structures involved in ingestion?

A
  1. Mouth
  2. Salivary Glands
  3. Teeth
  4. Tongue
  5. Esophagus
21
Q

What role does the mouth play in digestion?

A
  • First part of the digestive tract
  • Both physical and chemical digestion occurs there
22
Q

What role do the teeth play in digestion?

A
  • Tears and grinds food into smaller pieces
23
Q

What role do the salivary glands play in digestion?

A
  • Produce salivary amylase enzyme
  • Perform hydrolysis of carbohydrates (ex. polysaccharide —> disaccharide)
24
Q

What role does the tongue play in digestion?

A
  • Rolls food into smooth lump-like mass called a bolus
  • Bolus moves to back of throat pushes and pushes epiglottis down to prevent choking
25
Q

What role does the esophagus play in digestion?

A
  • Muscular tract that directs bolus to stomach via peristalsis (wavelike motion)
26
Q

What is the esophageal sphincter?

A

A circular muscle that must relax to allow bolus into stomach; contraction prevents stomach acid from entering esophagus.

27
Q

What are the two types of digestion?

A
  1. Physical Digestion
  2. Chemical Digestion
28
Q

Describe physical digestion

A
  • Peristalsis churns food, breaking it into smaller pieces and mixing with gastric juices
  • Thick liquid produced called chyme (liquefied food + gastric juices)
29
Q

Describe chemical digestion

A
  • Gastric juices (water, mucus, salts, hydrochloric acid, and enzymes) allow for digestion of food, but not own cells.
  • Pepsin activates in presence of HCl and initiates protein hydrolysis.
30
Q

What is the stomach?

A
  • Site of food storage and initial protein digestion
  • Sac-like, muscular organ with several tissue layers and a pyloric sphincter
  • Can hold about 1.5L
31
Q

What are the three main stomach cells?

A
  1. Peptic Cells
  2. Parietal Cells
  3. Mucous cells
32
Q

What is the function of peptic cells in the stomach?

A
  • Secrete pepsinogen (inactive enzyme)
  • Pepsinogen mixes with HCL, forming Pepsin (active enzyme)
  • Pepsin digests proteins into polypeptides
  • Pepsin can only work in acidic environments
33
Q

What is the function of parietal cells in the stomach?

A
  • Secrete HCl (Hydrochloric Acid)
  • Gives stomach a pH of 1 – 3
  • Kills bacteria
  • Activates pepsinogen into pepsin
34
Q

What is the function of mucus cells in the stomach?

A

Secretes mucous to make stomach lining (replaced every few days)

35
Q

How often are stomach cells destroyed and remade?

A

Every 3-4 days

36
Q

What is the small intestine?

A
  • Smaller diameter than large intestine, but 4 times longer
  • Mostly performs chemical digestion and absorption but some physical as well
37
Q

What are the three segments of the small intestine?

A
  1. Duodenum: first 25 cm of small intestine, contains ducts that connect to liver and pancreas (receives enzymes), most mechanical and chemical digestion occurs here
  2. Jejunum: continues breakdown, most absorption occurs here
  3. Ileum: absorbs nutrients and pushes undigested material to large intestine