3.3 - adaptations for nutrition Flashcards

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1
Q

define autotrophic

A
  • organisms that produces its own food
  • manufactures complex organic compounds from simpler inorganic molecules such as water + CO2
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2
Q

name the 2 types of autotrophic organisms

A
  • photoautotrphic
  • heteroautotrphic
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3
Q

what’s a photoautotrophic organism

A

organisms that obtains nutrition through photosynthesis

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4
Q

what’s a chemoautotrophic organism

A

organism that obtains nutrition through inorganic molecules, such as sulfur, in absence of light

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5
Q

define heterotrophic

A

organism that can’t produce its own food
obtains energy by feeding on organic compounds produced by other organims

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6
Q

what’s a saprotroph

A

organism that feeds by extracellular digestion
e.g: fungi

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7
Q

describe extracellular digestion by saprotrophs

A
  • release enzymes that catalyse breakdown of dead plant + animal material into simper organic matter
  • absorbs products of digestion
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8
Q

what’s meant by the term holozoic

A

describes a heterotrophic organism that internally digests food substances

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9
Q

what processes does holozoic nutrition involve

A
  • ingestion
  • digestion
  • absorption
  • assimilation
  • egestion
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10
Q

define ingestion

A

process by which organisms take food into their bodies

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11
Q

define digestion

A

process by which large, insoluble molecules broken down into smaller, soluble molecules that can be absorbed across cell membranes

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12
Q

name the 2 types of digestion

A
  • mechanical digestion
  • chemical digestion
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13
Q

what’s mechanical digestion

A
  • type of digestion that involves physically breaking down food into smaller features
  • increases total SA for chemical digestion
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14
Q

what’s chemical digestion

A

type of digestion that involves breaking down large, insoluble molecules into smaller, soluble molecules using enzymes

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15
Q

what’s assimilation

A

synthesis of biological compounds from absorbed simpler molecules

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16
Q

define absorption

A

movement of useful substances into bloodstream

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17
Q

define egestion

A

removal of undigested waste material from body

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18
Q

describe how unicellular organisms obtain nutrients

A
  • ingestion via phagocytosis
  • intracellular digestion (using hydrolytic enzymes) breaks down large, insoluble molecules into smaller, soluble molecules
  • products of digestion pass into cytoplasm by diffusion + active transport
  • undigested material removed by exocytosis
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19
Q

what’s a hydra

A

small, multicellular, freshwater organism of phylum Cnidaria

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20
Q

describe the structure of hydra

A
  • basic, undifferentiated sac-like gut
  • single opening, surrounded by tentacles, that serves as mouth + anus
  • single gut cavity (enteron)
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21
Q

outline process of digestion in hydra

A
  • hydrolytic enzymes secreted into enteron by endodermis
  • extracellular digestion partially digests food molecules
  • partially digested food transported, via phagocytosis, into endodermal cells where intracellular digestion takes place
  • undigested material egested from enteron via single opening
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22
Q

describe shape of gut in more complex organisms

A

tube like w/ 2 openings
mouth for ingestion
anus for egestion

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23
Q

what type of diet is human hut adapted to

A

omnivorous diet consisting of plant + animal material

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24
Q

state the names of the different layers of the gut wall

A
  • epithelium
  • mucosa
  • submucosa
  • muscle layer
  • serosa
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25
Q

what’s the epithelium

A

single layer of cells that line gut wall

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26
Q

describe the structure of the mucosa layer of the gut wall

A
  • mucous membrane lining gut wall
  • contains glands that secret digestive enzymes, mucus, + acid/alkaline liquid that provides optimum pH
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27
Q

describe the structure of the sub-mucosa layer of the gut wall

A
  • layer of connective tissue below mucous membrane
  • contains blood vessels + lymph for transport of digestion product + glands that secret an alkaline fluid
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28
Q

describe the muscle layer of the gut

A

layer of circular + longitudinal muscles beneath the submucosa

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29
Q

explain the action of circular + longitudinal muscles in peristalsis

A

contraction of circular muscle behind bolus of food + relaxation of longitudinal muscle in front forces food down gut

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30
Q

what’s the serosa

A

tough, protective layer that surrounds gut

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31
Q

what’s the buccal cavity

A

oral cavity through which food enter the body

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32
Q

which types of digestion take place in the buccal cavity

A

mechanical digestion + chemical digestion of starch

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33
Q

what’s the normal pH range of the buccal cavity

A

pH 6.5 to 7.5

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34
Q

what’s the function of teeth

A

crush + grind food into smaller pieces, increasing SA

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35
Q

what’s the tongue

A

muscular organ in buccal cavity that’s vital in chewing + swallowing of food

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36
Q

describe the function of salivary glands

A

secret amylase, mineral ions + mucus into buccal cavity

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37
Q

what’s the function of the oesophagus

A

carries food from buccal cavity to stomach by peristalsis

38
Q

describe the processes that take place in the stomach

A

mechanical digestion (mixing + grinding) + chemical digestion of protein

39
Q

what type of glands are found in the stomach

A

gastric glands

40
Q

describe the function of gastric glands

A

secrete endopeptidases, hydrochloric acid + and alkaline mucus into stomach

41
Q

what’s the normal pH of the stomach

A

pH 2

42
Q

what’s the role of the liver

A

secretes bile into small intestine via gallbladder + bile duct

43
Q

describe the composition + function of bile

A
  • consists of bile salts + and alkaline fluid
  • neutralise stomach acid, providing ideal pH for lipase
44
Q

state the 2 main divisions of the small intestine

A
  • duodenum
  • ileum
45
Q

what’s the duodenum

A

first section of small intestine where proteins + lipids are hydrolysed

46
Q

what’s the ileum

A

second section of small intestine that serves as main site of absorption of products of digestion

47
Q

what’s the normal pH range of the small intestine

A

pH 7 to 8

48
Q

what’s the pancreas + where is it located

A

large gland situated behind stomach

49
Q

describe the role of the pancreas

A

secretes enzymes + an alkaline fluid into duodenum via pancreatic duct

50
Q

what’s the large intestine also called

A

colon

51
Q

describe the function of the colon

A

reabsorbs water + minerals from waste materaial

52
Q

what’s the rectum

A

segment o large intestine that stores faeces prior to egestion

53
Q

which enzymes are involved in carbohydrate digestion
where are they found

A
  • amylase in saliva + pancreatic juice
  • maltase, sucrase, lactase on membrane of epithelial cells of small intestine
54
Q

what are the substrates + products of carbohydrates

A
  • amylase hydrolyses starch to maltose
  • maltase hydrolyses maltose to alpha-glucose
  • sucrase hydrolyses sucrose to glucose + fructose
  • lactase hydrolyses lactose to glucose + galactose
55
Q

what’s the optimum pH of amylase

A

pH 8

56
Q

which enzymes are involved in protein digestion
what are their roles

A

endopeptidases - hydrolyse non-terminal peptide bonds within protein to form smaller peptides
exopeptidases - hydrolyse terminal peptide bonds of protein to form dipeptides + amino acids

57
Q

give examples of endopeptidases

A
  • trypsin
  • pepsin
58
Q

describe how trypsin is produced

A
  • secreted by pancreas as inactive trypsinogen
  • enter kinase converts inactive trypsinogen into active trypsin in duodenum
59
Q

name the inactive form of pepsin

A

pepsinogen

60
Q

where is pepsinogen secreted from

A

gastric glands

61
Q

describe how inactive pepsinogen is converted into its active form, pepsin

A

hydrochloric acid converts inactive pepsinogen into active pepsin

62
Q

where are lipids digested

A

small intestine

63
Q

what must happen before lipids can be digested

A

must be emulsified by bile salts produced by liver
- breaks down large fat molecules into smaller, soluble molecules called micelles, increasing SA

64
Q

how are lipids digested

A

lipases hydrolyse lipids into monoglycerides, fatty acids + glycerol

65
Q

where are lipases found

A

in pancreatic juice

66
Q

state the processes by which absorption takes place in ileum

A
  • simple diffusion
  • facilitated diffusion
  • active transport
  • osmosis
67
Q

which molecules are absorbed by simple diffusion in ileum

A

monoglycerides, fatty acids + glycerol

68
Q

why can monoglycerides, fatty acids + glycerol be absorbed via simple diffusion

A

are non-polar molecules so can easily diffuse across membrane of epithelial cells

69
Q

what happens to monoglycerides, fatty acids + glycerol once absorbed into cells

A

are reformed into triglycerides, absorbed into lacteals + transported via lymphatic system into blood

70
Q

how are amino acids absorbed from lumen of gut

A

va active transport into epithelial cells + then into bloodstream by facilitated diffusion

71
Q

which molecules rely on co-transport from lumen of gut into cytoplasm of epithelial cells

A

glucose + other monosacchrides

72
Q

explain how sodium ions are involved in co-transport

A

actively transported out of cell into lumen, creating diffusion gradient
nutrients then taken up into cells along with Na+ ions

73
Q

how do monosaccharides pass from epithelial cells into bloodstream

A

via facilitated diffusion

74
Q

what are herbivores

A

animals that only eat plants

75
Q

describe the adaptations of herbivores to a high cellulose diet

A
  • long gut
  • loose articulation of lower jaw
  • horny pad on upper jaw
  • specialised dentition for grinding tough plant material
76
Q

describe how dentition of herbivores is adapted to its diet

A
  • small, flat incisors on lower jaw for cutting grass against upper horny pad
  • diastema between incisors + premolars - separates fresh grass from cud + enable manipulation of food by tongue
  • premolars + molars have large SA + sharply rigged biting surfaces for grinding plant material
77
Q

what are ruminants

A

mammals that digest plant material slowly in specialised four-chambered stomach + regurgitate it to chew is again, enabling efficient breakdown of fibre

78
Q

name the 4 chambers of the ruminant stomach

A
  • rumen
  • reticulum
  • omasum
  • abomasum
79
Q

describe the rumen

A

first stomach of ruminant
contains mutualistic bacteria that are able to hydrolyse cellulose into glucose

80
Q

what’s a carnivore

A

animal that preys on + eats other animals

81
Q

describe the adaptations of carnivores to high protein diet

A
  • short gut
  • powerful jaw muscles
  • specialised dentition for cutting + tearing meat
82
Q

describe how dentition of carnivore is adapted to its diet

A
  • sharp incisors to remove flesh from bone
  • large, pointed canines required to grow + kill prey
  • sharp carnissals (modified premolars + molars) to slice + shear meat
  • molars w/ sharp, flattened edges to crush bone
83
Q

what’s a parasite

A

organism that live on/in host + takes nourishment at expense of other organism

84
Q

name the 2 types of parasites

A
  • ectoparasites
  • endoparasites
85
Q

what are ectoparasites
give examples

A

parasites living on host
e.g: head louse

86
Q

what are endoparasites
give examples

A

parasites living in host
e.g: pork tapeworm

87
Q

how does head louse feed + transfer from one host to another

A
  • feeds by sucking blood from hosts scalp
  • transfer between hosts by direct contact
88
Q

where does pork tapeworm live

A

primary host - adult tapeworm lives in human gut
secondary host - larval form can develop in pigs

89
Q

how can humans + pigs become infected by pork tapeworm

A
  • humans become infected by consuming undercooked pork (containing larval forms of tapeworm)
  • pigs may become infected by ingesting contaminated faeces
90
Q

how does pork tapeworm feed

A

absorbs pre-digested nutrients in gut through cuticle

91
Q

how is pork tapeworm adapted to living in gut

A
  • thick cuticle
  • secretes anti-enzymes that prevent its digestion by host enzymes
  • scolex has strong suckers + hooks for attachment to gut wall
  • long, thin body proves large SA:V for absorption