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biology > ch6, nutrition in human > Flashcards

ch6, nutrition in human Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Food molecules have to be broken down because… (2)

A
  1. membrane of our cells is differentially permeable, need to be broken down to enter the cells
  2. food molecules are structurally different, need to break them down and use small molecules to build our own molecules
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2
Q

five main processes of nutrition in human

A
  1. ingestion
  2. digestion
  3. absorption
  4. assimilation
  5. egestion
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3
Q

digestive system consists of ___ and ___

A

alimentary canal and digestive glands

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4
Q

digestive glands produce _____

A

digestive juices

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5
Q

ingestion - process of chewing food is ____

A

mastication

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6
Q

4 types of teeth and their functions

A
  1. incisor - biting and cutting food
  2. canine - tearing flesh
  3. premolar & molar - crushing and grinding food
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7
Q

Dentition refers to..?

A

the type, number and arrangement of teeth in the jaws

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8
Q

A tooth can be divided into three regions:

A

the crown, neck, root

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9
Q

Enamel (3)

A
  • non-living and made mainly of calcium salts
  • hardest tissue in our body, protects tooth from wearing down in chewing
  • around roots, replaced by cementum, attatches to jawbone through periodontal membrane
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10
Q

Dentine (2)

A
  • bone like structure, large amount of calcium salt

- living tissue w strands of cytoplasm

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11
Q

Pulp cavity
- contains ___, ___, __
function of blood vessels and nerve fibres?

A
  • living cells, blood vessels, nerve fibres
  • blood vessels supply oxygen and nutrients to tooth, remove waste
  • nerve fibres detect temperature and pressure
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12
Q

Physical digestion

A
  • to break down by physical actions
  • doesn’t change chemical structure of food
  • increase surface area for digestive juice to act on
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13
Q

chemical digestion

A
  • catalysed by enzymes

- into small soluble molecules for easy absorption

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14
Q

digestion mainly occurs in ___, ___, ___

A

mouth cavity, stomach, small intestine

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15
Q

digestion in mouth cavity

3 substances + functions

A
  1. salivary amylase - break down starch to maltose
  2. mucus - sticky, bind food particles together, moistens and lubricates food for easy chewing and swallowing
  3. water - dissolves soluble substances in food, so we can taste it
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16
Q

Peristalsis:
1 wall of alimentary canal
2 after swallowed?

A
  1. circular muscles and longitudinal muscles

2. oesophagus contract alternatively to produce a wave-like movement, push food down to stomach

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17
Q

Digestion in stomach

2 muscles

A
  1. cardiac sphincter - prevent food from flowing back into oesophagus
  2. pyloric sphincter - controls release of food into the duodenum
18
Q

after food enters the stomach, muscles in the stomach wall will ___ to ___, and mix with ___

A

contract to churn the food

gastric juice

19
Q

Gastric juice contains:

3

A
  1. pepsin - protease which catalyses the breakdown of proteins into peptides
  2. hydrochloric acid - provides acidic medium for action of pepsin
    kills most bacteria in food
  3. mucus - protects stomach wall from being digested by pepsin or damaged by hydrochloric acid
20
Q

after a few hours in stomach, food becomes creamy liquid called ___

A

chyme

21
Q

Bile:
A green alkaline fluid produced continuously in __
temporarily saved in ___
it contains no ____

A

liver
gall bladder
digestive emzyme

22
Q

Bile contains: (3)

A
  1. Bile salts - emulsify lipids into small droplets
  2. bile pigments - dont take part in digestion, form from breakdown of haemoglobin, then excreted in faeces
  3. Sodium hydrogencarbonate - neutralizes acidic chyme
    provides alkaline medium
23
Q

pancreatic juice
produced by ___ through the ____
contains: (4)

A

pancreas, pancreatic duct
1. pancreatic amylase - breakdown of remaining starch into maltose
2. pancreatic lipase - catalyses breakdown of lipids into fatty acids and glycerol
3. proteases - breakdown of some proteins into peptides or amino acids
4. sodium hydrogencarbonate - neutralizes acidic chyme
provides alkaline medium

24
Q

intestinal juice: it is slightly alkaline/acidic?
contains ___, ___. ___
epithelium of small intestine has specialized cells that have ___(x) embedded in their ____, these (x) include ___ and ___

A

alkaline
water, mucus, sodium hydrogencarbonate
enzymes in their cell membranes
carbohydrates and proteases

25
Q 
function of intestinal juice
(2)
A
  1. carbohydrases - breakdown of disaccharides into monosaccharides
  2. proteases - catalyse the breakdown of peptides into amino acids
26
Q

structure of small intestine (3)

A
  1. the wall - circular muscles and longitudinal muscles, inner wall highly folded
  2. villi - fingerlike projections, has lymph vessel called lacteal, surrounded by network of capillaries
  3. epithelium - one cell thick, a lot of microvillis
27
Q

take in complex food and digest in the body. What’s this called?

A

Holozoic nutrition

28
Q

Many fungi and bacteria carry out this. they break down food outside the body then absorb the soluble nutrients into the body. What kind of nutrition?

A

saprophytic nutrition

29
Q

can be animals, plants, bacteria, live on or inside the body of other organisms and obtain food from them. What is this called?

A

parasitic nutrition

30
Q

food molecules are absorbed from the ___ into the ____ and ___ through ___ by (which 3) ?

A

lumen, capillaries, lacteals
epithelium
active transport, osmosis, diffusion

31
Q

digestion of water and water-soluble food molecules:

A

water soluble food molecules - diffusion and active transport
water - osmosis

32
Q

digeston of lipids and lipid-soluble food molecules:

A

fatty acids and glycerol by diffusion and recombining -> fine lipid droplets -> lacteal
lipid-soluble vitamins by diffusion directly into lacteal

33
Q

adaptaion of small intestine for absorption (5)

A
  1. very long, need sufficient time to complete digestion and absorption
  2. highly folded, many villi and microvilli, increase surface area for absorption
  3. epithelium is very thin, one cell thick, short distance for diffusion
  4. lacteal and capillaries -> absorbed food carried away rapidly
  5. peristalsis -> digested food molecules into close contact, keep steep concentration gradient, increase rate of diffusion
34
Q

absorption in large intestine: how?
remains of food moved by ____
semi-solid material left is called ___

A

some of remaining vitamins, water, minerals absorbed into blood in colon.
peristalsis
faeces

35
Q

how does constipation & diarrhoea form?

A

remains of food pass through the colon too slowly, a larger portion of water will be absorbed, faeces will be hard
if they pass the colon too quickly, larger potion of water will remain in faeces, result diarrhoea

36
Q

assimilation of water soluble molecules:
carried by ___ to the ____ through ____
some are ___, other ____…

A

blood, liver, hepatic portal vein
stored, processed then carried away to the heart through hepatic vein and vena cava. Then transported to parts of body through aorta

37
Q

assimilation of lipids & lipid soluble food molecules:
carried by ___ to the main ___
they enter the ___ near the neck region, where ___ joins ___.
They’re then carried by the blood to the ____ through ____, then transported to all other parts of body through ____

A

lymph, lymph vessel
blood, lymph vessel, blood vessel
heart, vena cava, aorta

38
Q

Fate of absorbed food - glucose

2

A
  • broken down by respiration in cells for releasing energy

- excess glucose converted to glycogen in liver and muscles and stored, may convert to lipids

39
Q

Fate of absorbed food - Lipids

A
  • used by cells to make cell membranes and some hormones
  • act as energy reserve, broken down to release energy when body is short of glycogen
  • excess lipids stored in adipose tissue around internal organs and under skin
40
Q

Fate of absorbed food - amino acids

A
  • make diff types of proteins for growth and repair, make enzymes and antibodies and hormones
  • broken down to release energy when carbs and lipids are used up
  • excess CANNOT be stored, are broken down in liver through deamination
41
Q

egestion

A
  • undigested and unabsorbed materials form faeces
  • contain dietary fibre, bacteria, secretions from alimentary canal, dead cells from intestinal wall and water
  • brown bcs of bile pigments
  • ring of muscles called anal sphincter

biology (5 decks)

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