3.3 Flashcards
1
Q
what is autotrophic nutrition?
A
organisms that use simple inorganic molecules to synthesise large complex organic molecules
2
Q
what are the two types of autotrophic nutrition?
A
photoautotrophic and chemoautotrophic
3
Q
what are photoautotrophs?
A
using light energy in photosynthesis
4
Q
what are chemoautotrophs?
A
use energy released in chemical reactions in chemosynthesis
5
Q
what is heterotrophic nutrition?
A
organisms that obtain complex organic molecules from other organisms
6
Q
what are the 4 types of heterotrophic nutrition?
A
holozoic, saprotrophic, parasitic, mutualistic
7
Q
what is holozoic nutrition?
A
internal digestions involving enzymes
8
Q
what are the stages in holozoic digestion?
A
ingestion, digestion, absorption, assimilation, egestion
9
Q
what is saprotrophic digestion?
A
feed in the dead/decaying by secreting enzymes onto the food and small soluble products of digestion are absorbed back in
10
Q
what adaptations do fungi have for saprotrophic digestion?
A
hyptae create a large surface area which are one cell thick
11
Q
what is parasitic digestion?
A
parasites obtain nutrients from another organism by living in or on a host organism which is harmed
12
Q
what is mutualistic digestion?
A
an association between 2 species and there is a nutritional benefit to both
13
Q
what is lichen made of?
A
alga (photosynthesis produces glucose) and fungus (hyptae absorb minerals)
14
Q
what is rhizobium made of?
A
nitrogen fixing bacteria (make nitrates for plants) in root nodules of clover (make glucose for bacteria)
15
Q
what are psendopodia?
A
temporary extensions of a cells cytoplasm
16
Q
describe how food is ingested in amoeba
A
amoeba uses its psendopodia to engulf its prey called phagocytosis. the food is enclosed within a food vacuole in the cytoplasm
17
Q
what happens for digestion to occur in amoeba?
A
smaller vacuoles containing digestive enzymes fuse with the food vacuole membrane. they release enzymes into the vacuole and they digest the food
18
Q
where does absorption occur in amoeba?
A
the small molecules from digested food are absorbed across the membrane that surrounds the vacuole in the cytoplasm
19
Q
what type of digestion is amoeba?
A
intracellular
20
Q
what is the structure of a hydra?
A
hollow body cavity, endoderm, jelly layer, ectoderm, mouth, tentacles with stinging cells.
comprises of two layers of cells which are separated by a jelly layer containing a network of nerve fibres. it is cylindrical and has tentacles (usually 6) surrounding its mouth which is its only body opening
21
Q
describe how hydra ingests food
A
stringing cells discharge which paralyses prey and the tentacles move prey into mouth and into body cavity
22
Q
what does extracellular digestion mean?
A
the enzymes are secreted into the hollow cavity
23
Q
what type of digestion happens in hydra?
A
extracellular and then intracellular
24
Q
what does intracellular digestion mean?
A
food particles are taken into cells by endocytosis for digestion to occur
25
what is the difference between a hydras gut and a tube gut?
hydras gut only have one opening and tube guy has two
26
what is the gut wall structure?
lumen, mucosa, submucosa, muscle layer (circular then longitudinal), serosa
27
what is the mucosa?
innermost in contact with food
28
what do goblet cells do?
produce mucus for lubrication and prevent auto digestion
29
what is the epithelial tissue for in the mucosa?
glandular- secrete enzymes/digestive juices
adapted for absorption
30
what is the submucosa? and explain its structure
below mucosa. made of connective tissue, contains lots of capillaries for transport of absorbed end products of digestion, contains nerve fibres to coordinate muscle movements
31
what is the muscle layer responsible for?
peristalsis
32
what is peristalsis?
wave of muscular contraction that moves food through the digestive system
33
what are the places of thickened muscles called?
sphincters- they control movement of food (in and out of stomach)
34
what is the serosa?
outermost layer, tough connective tissue, protects the organs from friction with other organs
35
what happens in the mouth?
ingestion, chewing (mastication) which is mechanical digestion
36
what is chewing for?
to increase SA for enzyme action and breaks down food for swallowing
37
what does the tongue do?
mixes food with saliva
38
what is saliva
a watery mixture of mucus (binds food together) , salivary amylase and hydrogen carbonate ions (neutralise acids and keep optimum ph for salivary amylase)
39
how is food moved in the oesophagus?
peristalsis
40
what is the function of goblet cells in the oesophagus?
secrete mucus to reduce friction and lubricate the passage of food
41
what layer of the gut is well developed in the oesophagus?
muscle layer
42
what happens to the food in the stomach?
churned with gastric juice
43
where does protein digestion start?
stomach
44
what are the adaptations of the stomach?
mucosa is folded to form rugae (allow stomach to stretch and expand), third layer of muscle called oblique layer (in the circular muscle) which is at angle to help produce strong contractions to churn food
45
what does gastric juice contain?
mucus, HCl, pepsinogen
46
what is the function of mucus in the stomach?
lubrication and protection against auto digestion
47
what is the function of HCl in the stomach?
kills pathogens and provides the optimum pH for pepsin (pH 1or 2)
48
what is pepsinogen?
inactive precursor of the enzyme pepsin
49
why is pepsin secreted as pepsinogen?
so the chief cells/ gastric gland cells aren’t digested
50
how is pepsin activated?
pepsinogen + H+ from HCl
51
what type of enzyme is pepsin?
endopeptidase
52
what is an endopeptidase?
hydrolises peptide bonds within the polypeptide chain to produce shorter peptides
53
what is an exopeptidase?
hydrolises the terminal peptide bond to break off individual amino acids
54
why does a mixture of endopeptidases and exopeptidases give the fastest rate?
the endopeptidases produce more ends for the exopeptidases to work on
55
what is the duodenum?
first part of the small intestine, main site of digestion
56
what is the structure of the duodenum?
mucosa is folded to form villi, villi move so that they come into contact with food, between villi are crypts of Leiberkuhn, in the submucosa Brunners Glands are present
57
where does the duodenum receive secretions from?
liver, pancreas, duodenum wall
58
what secretion does the duodenum receive from the liver?
bile
59
what path does bile take from liver to duodenum?
liver- gall bladder - bile duct - duodenum
60
what does bile contain?
bile salts, sodium hydrogen carbonate
61
what do bile salts do?
emulsify lipids, increase SA for action of lipase which is an example of physical digestion
62
what does sodium hydrogen carbonate do?
neutralises stomach acid, provides optimum pH for digestion in duodenum
63
what does the pancreas produce?
pancreatic juice
64
what path does pancreatic juice take from pancreas to duodenum?
pancreas - pancreatic duct - duodenum
65
what does pancreatic juice contain?
pancreatic amylase, pancreatic lipase, trypsinogen, exopeptidase (carboxpeptidase), sodium hydrogen carbonate
66
which reaction is pancreatic amylase used in?
starch -> maltose
67
which reaction is pancreatic lipase used in?
triglycerides -> glycerol + 3 fatty acids
68
what is trypsinogen?
inactive precursor of trypsin
69
what activates trypsin?
enterokinase
70
what is enterokinase?
enzyme made in the duodenum
71
what does the duodenum wall produce?
intestinal juice (alkaline mucus= no enzymes)
72
where is alkaline mucus secreted from in the duodenum wall
brunners glands
73
where do the final stages of carbohydrase and protein digestion occur?
intracellular
74
where are the enzymes for final stages of digestion found?
present in the plasma membrane of the epithelial cells of mucosa
75
how many carbohydrase enzymes are there?
3 - maltase, sucrase, lactase
76
how many dirtied enzymes are there?
many different ones due to 20 amino acids
77
what is the ileum?
main site of absorption
78
what adaptations does the ileum have?
large surface area (long, folded walls, villi, microvilli), short diffusion pathway (1 layer of columnar epithelium on villi) good blood supply (maintains concentration gradient)
79
how are glucose and amino acids absorbed?
by co transport with Na+
80
how does co transport of glucose (or amino acids) and Na+ work?
1- active transport of Na+ out of epithelial cell
2- lowers conc of Na+ in cell
3- facilitated diffusion of Na+ into cell
4- glucose binds to carrier protein and moves through membrane with Na+ (even if no conc gradient)
5- facilitated diffusion of glucose into the blood
81
why does co transport occur?
initially diffusion is fine due to conc gradient but will reach an equilibrium so co transport ensures that as much glucose (and amino acids) are absorbed as possible
82
how many co transport proteins are there for glucose?
1 (alpha glucose)
83
how many co transport proteins are there for amino acids?
20
84
what is the path the absorbed glucose and amino acids take?
villus capillary - hepatic portal vein - liver
85
what happens in the large intestine?
water is absorbed, faeces form which are stored in rectum and egested through anus
86
how are fatty acids and glycerol absorbed into body?
1- fatty acids and glycerol enter epithelial cell
2- triglycerides reform
3- fatty globules and proteins combine in golgi
4- exocytosis of product into lacteal
5- transported in the lymph
87
what is the optimum pH of salivary amylase?
6.5-7.5
88
what is the optimum pH of pancreatic amylase?
7.0 - 8.5
89
what is the optimum pH of maltase?
6.5
90
what is the optimum pH of lactase?
6.7
91
what is the optimum pH of sucrase?
2
92
what is pancreatic lipases substrate?
triglycerides
93
what is the product of triglycerides being broken down?
glycerol + 3 fatty acids
94
what is the site of production of pancreatic lipase?
pancreas
95
what is the site of action for pancreatic lipase?
duodenum
96
what is the optimum pH for pancreatic liapse?
8
97
what is pepsins substrate?
protein
98
what is the products of proteins?
amino acids and dipeptides
99
what is site of production for pepsin?
stomach (chief cells)
100
where is the site of action for pepsin?
stomach
101
what is the optimum pH for pepsin?
1/2
102
what is the substrate fro trypsin?
proteins
103
what is the site of production for trypsin?
pancreas
104
what is the site of action for trypsin?
duodenum
105
what is the optimum pH for trypsin?
8
106
what is the substrate for enterokinase?
trypsinogen
107
what is the products from trypsinogen?
trypsin
108
what is the site of production for enterokinase?
duodenum
109
what is the site of action for enterokinase?
duodenum
110
what is the optimum pH for enterokinase?
8
111
what is the substrate for dipeptidase?
dipeptides
112
what are the products from dipeptides?
amino acids
113
what is the site of production for dipeptidase?
plasma membrane of duodenum and ileum
114
what is the site of action for dipeptidase?
plasma membrane of duodenum and ileum
115
what is the optimum pH for dipeptidase?
5.5
116
what are parasites?
they live in (endoparasite) or on (ectoparasite) a host organism, they obtain nutrients from the host which causes harm to the host
117
what type of parasites are headlouse? and why?
ectoparasites. live on scalp and suck blood
118
how are tapeworms spread?
human = primary host, faeces containing eggs, pig = secondary host, undercooked meat containing cysts eaten by human
119
what do tapeworms do?
attach to the wall of the small intestine
120
what adaptations do tapeworms have?
large surface area:vol, thin, scolex (hooks+suckers), thick cuticle
121
what does a large sa:vol and thin mean to a tapeworm?
effective absorption of nutrients (end products of digestion) so no digetsive system
122
what does having hooks and suckers mean for a tapeworm?
attaches to gut wall and prevents removal by peristalsis
123
what does a thick cuticle mean for a tapeworm?
protects the tapeworm against digestion by enzymes or damage by acid/other secretions
124
what does being a hermaphrodite mean to a tapeworm?
male + female reproductive organs means theres a higher chance of lice cycle continuing
125
what dentition adaptations do carnivores have?
incisors= sharp, grip prey, tear muscle from prey. canines= large, curved and pointed, siezing and piercing prey , killing, tear muscles. premolars+molars= have 'cusps' (sharp points), cut muscle and grind. carnassials= specialised molars, upper and lower slide past eachother shearing flesh from bone
126
what dentition adaptations do herbivores have?
incisors+canines = only on lower jaw, small and sharp. tongue wraps round grass and pulls in tight against dental pad. incisors and canines slice through grass. diastema= gap between canines and premolars on lower jaw, allows tongue to move vegetation over molars. molars= WM (interlocking), allows grinding of teeth but wears down so open roots to allow continuous growth, worn down material is replaced
127
what are ruminants?
animals with a stomach which consists of 4 chambers
128
what are the parts to a 4 chambered stomach?
from the oesophagus, rumen, back to oesophagus, reticulum, omasum, abosum, to the small intestine
129
what happens to food in a ruminant?
food is chewed and swallowed, partially digested food is regurgitated, food is rechewed and reswallowed
130
what is in the rumen?
bacteria and protozoa which ferment cellulose
131
what happens in the rumen/reticulum?
the products of cellulose fermentation may be used by bacteria or absorbed by ruminant and used as energy sources
132
what are the adaptations of the rumen / reticulum?
many villi/honeycomb like structures = large surface area for absorption
133
what happens to rumen products that aren't absorbed?
they are belched
134
what is the relationship between ruminants and the bacteria?
mutualistic
135
what is rumination?
when partially digested food is regurgitated and chewed
136
what happens after rumination?
food passes through the omassum and is digested like humans
137
what are caecum/appendixes used for in rabbits/horses?
to harbour their cellulose digesting bacteria
138
how do herbivores absorb products from bacterial fermentation?
eat their own faeces (coprophagy/refection) and absorb
