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Biology🔬🧬 > Digestion > Flashcards

Digestion Flashcards

1
Q

Nutrition

A

Way in which organisms obtain complex organic molecules
Raw materials from food help build and maintain structures

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2
Q

autotrophic nutrition

A

Organisms make their own food from single inorganic raw materials, CO2 and water into organic materials

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3
Q

Photoautotrophic organisms

A

Use light as energy source and perform photosynthesis
Green plants, some protocistor and some bacteria - type of nutrition is holophytic

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4
Q

Chemoautotrophic organisms

A

Uses energy from chemical reactions - or prokaryotes and perform chemosynthesis
Less efficient than photosynthesis and organisms that do this are no longer dominant life forms

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5
Q

Heterotrophic nutrition

A

Organisms cannot make their own food and consume complex organic molecules produced by autotrophs- consumers
Either eat autotrophs or organisms that have eaten autotrophs
Eg. Animals, dependent on producers for food
Animals, funky, some protoctista and some bacteria

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6
Q

saprotrophic nutrition

A

Used by all fungi and some bacteria
Saprotrophs feed on dead or decaying matter
No specialised digestive system secrete enzymes onto food material outside body for extracellular digestion
Absorb soluble products of digestion across the cell membrane by diffusion and active transport

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7
Q

Decomposers

A

Microscopic sapotrophs and are important in decaying leaf litter and recycling nutrients
Eg. Rhizopus

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8
Q

Rhizopus
process

A

1) Enzymes secreted from the tip of hypha digests the substrate ( organic matter which fungus grows and feeds)

2) Product absorbed and transports through mycelillum and enzymes perform extracellular digestion

3) nutrients absorbed back into fungal hyphae

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9
Q

Parasitic nutrient

A

obtaining nutrition from another living organism, the host

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10
Q

parasites

A

Endoparasites live in body of host, while Ectoparasites live on its surface
Parasites host always suffers some harm, often death
Parasites adapted in many ways - highly specialised for way of life Eg. Tapeworm , Head lice, potato blight, plasmodium

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11
Q

Holozoic nutrition

A

Nutrition used by most animals
Ingest food digest and egest indigestive remains
Food processed inside body in a specialised digestive system. In material absorbed into body tissues and used by cells

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12
Q

nutrition in unicellular organisms

A

Eg Amobea uses holozoic nutrition
Single sound organisms with large surface area:volume
Obtain all nutrients they need by diffusion, facilitated diffusion, active transport across cell membrane
Take in larger molecules and microbes by endocytis into food vacuoles, fuse with lysosomes and contents digested by lysosomal enzymes
Products of digestion absorbed into cytoplasm and indigestible remains are egested by Exocytis

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13
Q

Nutrition in multicellular organisms

A

single body opening- eg. Hydra
2 layers cells: On ectoderm and endoderm, separated by jelly layer (contain network nerve fibres)
Tentacle surrounding, only open body opening
Tentacles extend and when small organisms brush against tentacles , stinging cells discharged and paralyse prey
Move prey through mouth into hollow body cavity

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14
Q

Endodermal cells

A

Some secrete protease and lipase; Prey digested extracellularly and products absorb into cells
Other are phagocytic and engulf food particles (digest in food vacuoles)
Indigestible remains are egested through the mouth

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15
Q

tube gut

A

Tube with two openings, distinct anterior and posterior and digestive system. That mouth and indigestible waist like egested at the anus

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16
Q

human digestive system
food must be digesed

A

Food must be digested because:
Molecules are insoluble and too big to cross membrane and be absorbed into blood
Polymers must be converted to monomers so they can be rebuilt into molecules needed by body cells

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17
Q

peristalisis

A

how food is moved across digestive system
- longitudinal muscles contract to push food forwards then relax
- Circular muscles contract behind the bolus then relax; waiver contraction pushes the bolus down

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18
Q

functions of the digestive sstem

A

Ingestion- Taken food into body through buccal cavity
Digestion- Breakdown of large and solid ball into soluble molecules small enough to be absorbed into blood
Absorption- Passage of molecules through gut wall into blood
Egestion- Elimination of waste not made by body

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19
Q

chemical digestion

A

Digestive enzymes, bio, stomach acid contributes to breakdown food

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20
Q

mechanical digestion

A

Cutting and crushing by teeth and muscle contraction of gut wall - increases surface area so enzymes can act

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21
Q

function of mouth

A

Ingestion, digestion of starch and glycogen

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22
Q

function of oesophagus

A

Carriage of food to the stomach

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23
Q

function of stomach

A

Digestion of proteins

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24
Q

function of duedenum

A

Digestion of carbohydrates, fats and proteins

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25
Q

function of ileum

A

Digestion of carbohydrates, fat, protein; absorption of digested food and water

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26
Q

function of colon

A

Absorption of water

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27
Q

function of rectum

A

Storage of faeces

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28
Q

function of anus

A

Egestion

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29
Q

Structure of gut wall

A

4 layers of tissue surrounding cavity (lumen)
serosa
Muscle
submucosa
Mucosa

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30
Q

serosa

A

Outermost layer, tough connective, protecting gut wall.
Gut moves while processing food at Serosa reduces friction (peritoneum) with other abdominal organs

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31
Q

muscle

A

Two layers in different directions
Inner - circular muscle
Outer- longitude or muscle
They make coordinated waves of contraction (peristalsis)
Behind boiler food, circular muscles contract and longitudal on muscles relaxed, pushing food along

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32
Q

submucosa

A

Spin layer of connective tissues, containing blood and lymph and vessels - remove absorbed products of digestion and nerves that coordinate peristalsis

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33
Q

mucosa

A

Into most layer and lines the gut wall
Epithelium secrets mucus lubricating and protecting mucosa.
In some regions of the gut it secrets digestive juices and in others, absorbs digested food

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34
Q

buccal cavity- mouth

A

Food mixed with saliva by the tongue and chewed by teeth
Food surface area increases, giving enzymes more access

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35
Q

saliva in mouth
contents

A

contains:
- Amylase, Beginning digestion of converting glycogen into maltose
- HCO3- and CO32- ions, P H of saliva varies between 6.2- 7.4 but optimum pH of salivary amylase is 6.7-7.0
- mucus, lubricating foods passage
- mucin, glues food together

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36
Q

oesophagus

A

Carries food to the stomach. Shows tissue layers in simplest form
Bolus- food swallowed

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37
Q

Stomach

A

Food enters and kept there by contraction of two sphincters/ rings of muscle
2dm3, food stays for several hours
Stomach wall muscles contract rhymically and mix food with gastric juice- secreted by glands in stomach walls

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38
Q

gastric juice

A

secreated from glands in depressions in mucosa- gastric pit

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39
Q

Gastric pit

A
  • entrance to gastric pit at top
  • mature goblet cells
  • submucosa
  • Epithelial layer
  • Oxyntic cell
  • immature mucus cells
  • gastric pit
  • Zymogen/ chief cell
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40
Q

Mature mucus secreting goblet cells

A

Mucus secreted by goblet cell at the top of the pit forms a lining, protecting stomach wall from enzymes and lubricates food

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41
Q

Oxyntic cell

A

secreates HCL
Hydrochloric acid lowers PH of stomach contents to PH2 for enzymes. kills bacteria in the food

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42
Q

Zymogen/ chief cell

A

secreates enzymes
Peptidases, secreted by Zymogen at base of gastric pit
pepisinogen (inactive enzyme) is secreated and activated by H+ ions to pepsin, an endopeptidase, hydrolyses protein to polypeptides

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43
Q

small intestine

A

2 regions: Deodenum, Ileum
Relaxation of the pyloric sphincter at base of stomach allows partially digested food into the deodenum, little at a time
now everything is great deodenum receive secretions from liver and pancreas. pH of 8-9

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44
Q

Bile

A

Made in liver, stored in Gallbladder, passes through bile duct into deodenum
- no enzymes
- contains bike salts, amphipahic
Emulsifies liquids by lowering surface tension and brake large globules into smaller ones- increase surface area and meat digestion by lipase more
More alkaline and neutralises acid and food coming from stomach provides suitable pH for enzymes in small intestine

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45
Q

pancreatic juice

A

For created by Islet cells- exocrine glands in pancreas, enter deodenum through pancreatic duct

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46
Q

crypts of Lieberkühn

A

Food coming from stomach is lubricated by mucus, neutralised by alkaline secretions from cells at base of crypts of lieberkühn/ Brunner’s gland

47
Q

Ileum

A

Epithelial cells lining the ileum have finger like projections called Villi which synthesised digestive enzymes:
- Endopeptidase and exopeptidase
- carbohydrates

48
Q

Endopeptidases and exopeptidases

A
  • Peptidases are secreted by villas epithelial cells and digestion continues in the gut lumen
  • Dipeptidases in cell surface membranes digest dipeptides to amino acids
49
Q

carbohydrates

A

Carbohydrates are created and digestion continues in the gut lumen
Carbohydrates in cell surface membrane digest disaccharides into monosaccharides
Some disaccharides absorbed so their digestion is intracellular
Amylase hyrdolyses starch and glycogen to maltose

50
Q

Digestion of protein

A

protease, peptidase
Digested into polypeptides and dipeptides into amino acids

51
Q

Endopeptidases

A

Hydrolyzes peptide bonds within the protein molecule

52
Q

Exopeptidases

A

hydrolyses the terminal peptide binds at end of shorter polypeptides

53
Q

Absorption

A

occurs mainly in small intestine by diffusion, facilitated diffusion and active transport
Active transport needs ATP

54
Q

Ileum- absorption

A

Lining folded
On the surface of folds - villi
have projections- microvilli
Increase SA for absorption
Self are produced at base of glands and move out to replace old cells sloughed off by the food

55
Q

Section of ileum wall

A

Crypts of lieberkühn- gap between
Epithilium- one cell thick
Villi
Capillary- ends
Lacteal- middle
Venule- carries blood to hepatic partalvein, middle bottom
Artieole- first bottom
Lymph vessel- last bottom
Circular muscle
Longitudinal muscle

56
Q

villus

A

Inside Villus is a dense network of blood vessels
They absorb digested food molecules
Also lacteal- blind ended tube of lymphatic system, involved in absorption of lipids

57
Q

fates of nutrients- glucose

A

Glucose is taken to body cells and respired for energy or stored as glycogen, in liver and muscle cells. The excess is stored as fat

58
Q

fates of nutrients- amino acids

A

Amino acids taken to body cells for protein synthesis
Excess cannot be stored so liver deaminates and converts NH2 groups to urea, Carried in blood and excluded at the kidney
remains of amino acid molecules are converted into carbohydrate for storage or conversion to fat

59
Q

large intestine
undigested

A

Undigested food, mucus, bacteria and dead cells pass into the colon
Colon wall has fewer villi in the ileum and these will have major role in water absorption

60
Q

vitamin k and fulic acid - large intestine

A

Secreted by mutualistic microorganisms living in the colon, and minerals absorbed from the colon
As material passes along:, water is absorbed and by the time it reaches the rectum, material is semi solid
It passes along the rectum and is egested as faeces in process called defecation

61
Q

adaptions for diet

A

When reptiles and amphibians ingest food they swallow it whole
Mammals retain their food in their mouth while it is cut and chewed
Mammals are the only vertebrates to have a palate separating the nasal and mouth cavities, so they can hold food in mouth and chew while breathing

62
Q

carnivore

A

Eats only animals and so its diet is mostly protein
Small intestine is short in relation to body length reflecting the ease with which protein is digested
Large intestine is straight with smooth lining

63
Q

herbivore

A

It’s only plant material
Smaller testing is long in relation to body length because plant material is not readily digested and a long gut allows enough time for digestion and absorption of nutrients

64
Q

omnivore
pouch

A

Gut length is intermediate
A herbivore and omnivore has a pouch large intestine so it can stretch to accommodate larger volume of faeces produced in digesting plants- Much of which is cellulose
Large instestine is also long with Villi where water is absorbed

65
Q

Dentition

A

Food must be cut, crushed, ground or sheared
Humans have incisors, canines, premolars and molars

66
Q

Dentition of Herbivores

A

Plant cell walls are tough to eat as they contain cellulose and liggin and sometimes silica
The teeth of Hebivores are modified so that the cells can’t be thoroughly ground up before entering the stomach

67
Q

Herberores - incisors and canine
1

A

Grazing Herbivore - incisors on lower jaw only
Canine teeth are indistinguishable from the incisors
Animal wraps his tongue around the grass and pulls it tight across the leathery ‘dental pad’ on upper jaw
then lower incisors and canine slice through it

68
Q

herbivore- diastema
2

A

Gap called diastema separates front teeth from premolars
Tongue and cheeks operate in this gap, moving freshly grass to large grinding surfaces of the molars

69
Q

herbivore- molar
3

A

molars interlock- like a W into an M
lower jaw moved side to side- produces circular grinding action in a horizontal plane.
with time- Grinding services of teeth become worn, exposing sharp edged enamel ridges further increasing efficiency of grinding
Teeth have opened unrestricted roots so they continue to grow throughout animals lives replacing material worn down

70
Q

Herbivore- skull and muscles

A

Hibbard does not need strong muscles attached to its jaws because it’s food is not likely to escape
Its skull is relatively smooth, reflecting absence of sight for strong muscles to attach

71
Q

Dentition of carnivores

A

They have teeth adapted for catching and killing prey, cutting or crushing bones and tearing meat

72
Q

Carnivores - incisors
1

A

sharp incisors grip and tear muscle from bone

73
Q

carnivore- canine
2

A

Canine teeth are large, curved and pointed for piercing and seizing prey for tearing muscles and killing

74
Q

carnivore- premolars and molars
3

A

Premolars and molars have cusps, which are sharp points that cut and crush

75
Q

carnivore- carnassials
4

A

Carnivals have pair of specialised cheek teeth called carnassials in each side
They slide past each other like scissor blades, these shear the muscle off the bone
Large and easily identifiable

76
Q

carnivore- lower jaw
5

A

Lower Jaw moves vertically
Carnivals open their doors very wide when they deal with prey and side to side movements could dislocate their jaw

77
Q

ruminant

A

a cud chewing herbivore possessing a ‘stomach’ divided into 4 chambers
largest-rumen, contains mutualistic microbes

78
Q

rumen

A

chamber in the gut of ruminant herbivores, in which mutualistic microbes digest complex polysaccharides

79
Q

Mutualism

A

A close Association of organisms from more than one species, providing benefits to both

80
Q

Mutualistic microbes

A

Much of Herbivores food is cell war material, mainly cellulose
Animals cannot make cellulase and cannot digest the beta glycosidic bonds in cellulose
Therefore they rely on mutualistic microbes living in their gut to secrete the enzyme instead

81
Q

What do mutualistic microbes include

A

Bacteria, fungi and protocista which live in the Rumen

82
Q

Cellulose digestion
1

A

Grass is cut by the teeth and mixed with saliva to form the curd, swallow down the oesophagus to the rumen

83
Q

The Rumen
2

A

Chamber in which food mixes with microbes. Microbes secrete enzymes which digest cellulose into glucose
Glucose is fermented to organic acids that are absorbed into the blood and are an energy source for cow
Carbon dioxide and methane released as waste products

84
Q

Cellulose digestion
3

A

Fermented grass passes to the reticulum and is reformed into cud. It is regurgitated into the mouth for further chewing

85
Q

Cellulose digestion
4

A

Cud may be swallowed and regurgitated into the mouth several times

86
Q

Cellulose digestion
4

A

Cut passes next into the omasum where water and organic acids made from fermented glucose are absorbed into the blood

87
Q

Cellulose digestion
5

A

4th chamber -abomasum is the ‘true’ stomach, where protein is digested by Pepsin and at P H two

88
Q

Cellulose digestion
6

A

Digested food passes to the small intestine, from where the products of digestion are absorbed into the blood
Functions of large intestine are comparable with those of human

89
Q

Parasites

A

An organism that obtains nutrients from another living organism or host, to which it causes harm
They may live on or in an organism

90
Q

Parasites in plants

A

Bacteria fungi viruses, nematodes and insects

91
Q

Parasites in animals

A

Also parasited by Protoctistans, tapeworms and mites

92
Q

Parasites in bacteria

A

By viruses called bacteriophages

93
Q

pork tape worm

A

Taenia Solium
It has no competition- cannot be predated upon
Endoparasite

94
Q

Pork tapeworm description

A

Ribbon like- shape allows plenty of space for host food to move past it
Ten metres long
And your end - scolex made of muscle carrying suckers and hooks
But he has linear series of sections proglottids
Rostellum

95
Q

proglottids
mature and terminal

A

mature proglittids- Contain uterus with embryos

Terminal proglottids- Fall off and are discharged with the faeces

96
Q

Tapeworms Lifecycle

A

Requires it to alternate between two hosts
Primary host- human
Secondary host - pig
larval forms develop
The peak becomes infected when food is contaminated with human faeces
Human are infected by eating undercooked pork containing live larval forms

97
Q

how the tape worm survives hostile conditions in the gut

A
  • Surrounded by digestive juices and mucus
  • Must withstand peristalsis
  • Experiences pH changes as it moves down the gut to the deunodum
  • Exposed to hosts immune system
  • If host dies parasite dies
98
Q

Tapeworm structural modifications
Scolex

A

Has suckers and a double row of curved hooks to attach it strongly to the duodenum wall

99
Q

Tapeworm structural modification
Cuticle

A

a thick body covering protecting it from the host’s enzymes and immune system

100
Q

Tapeworm structural modifications
Enzyme inhibitors

A

It makes enzyme inhibitors which prevent the hosts enzymes digest in it

101
Q

Tapeworm structural modifications
Reduced gut

A

It has a very reduced gut; a large surface area to volume ratio let’s say absorb pre digested food over its whole surface

102
Q

Tapeworm structural modifications
hermaphrodite

A

Each proglottid has male and female reproductive organs. Guts usually only has one tapeworm but each mature proglottid may contain forty thousand eggs - pass out of host body with faeces
Lots of eggs increase chances of infecting secondary host

103
Q

Tapeworm structural modifications
Resistant shells

A

The eggs have resistant shells and survive until eaten by pig. Hatch and move through intestine wall into pig muscles
remain dormant there until meat is eaten

104
Q

harmful effects of pork tape worm

A

Adult tapeworm may cause little discomfort but long term infection may produce taeniasis - giving abdominal pains and weakness
Can be treated with drugs
If eggs are eaten directly - embryos can form cysts in various organs and damage surrounding tissue

105
Q

Head lice

A

Pediculus
ectoparasite
Wingless insects. Fly and legs are poorly adapted to jumping and walking so they are transferred from one host to another by direct contact
They die if removed from human

106
Q

3 stages in Louse life cycle

A

Adult Louse lays eggs - hatch after 12 weeks into nymphs leaving nits, empty egg cases
Nymph is like an adult but smaller
Becomes adult after 10 days and feeds on blood

107
Q

Absorption of amino acids

A

Amino acids absorbed into epithelial cells by active transport and, as amino acids, they pass into capillaries by facilitated diffusion
Water soluble and dissolving the plasma

108
Q

Absorption of glucose

A

Glucose passes into epithelial cells with sodium ions by co-transport
Move into capillaries
sodium by active transport and glucose by facilitated diffusion and dissolving plasma
Diffusion I’m facilitated diffusion are slow and not all the glucose is absorbed
To prevent it leaving body in faeces, some is absorbed by active transport

109
Q

Absorption of fatty acids

A

Fatty acids and monoglycerides diffuse into epithelial cells and into lacteals
Lacteals are blindly ending lymph capillaries in the villi
They are part of lymphatic system transport soluble molecules to the left subclavian vein near the heart

110
Q

Absorption of minerals

A

minerals are taken into blood by diffusion, facilitated diffusion and active transport and dissolve in plasma

111
Q

Absorption of vitamins

A

Vitamin B and C are water soluble and are absorbed into blood
Vitamin A D and E are fat soluble and are absorbed into lacteals

112
Q

autotroph

A

Organism that synthesises its own complex organic molecules from simpler molecules using either light or chemical energy

113
Q

Heterotroph

A

Organism that obtains complex organic molecules by consuming other organisms

114
Q

Saprotroph/ saprobiont

A

Organism that derives energy and raw materials for growth from extracellular digestion of dead or decaying material

Biology🔬🧬 (11 decks)

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