Lesson 3 Flashcards
(150 cards)
1
Q
what is the percentage of elements of the periodic table essential for life ?
A
25%
2
Q
do we also share chemical similarities with nonliving objects ?
A
no mostly made up of different elements
3
Q
what is the smallest unit of matter
A
the atom
4
Q
what is matter
A
anything that takes up space
5
Q
the human body is composed of what
A
matter
6
Q
how many elements is the human body composed of ?
A
about 23
7
Q
water is composed of how many elements and atoms ?
A
2 elements
3 atoms
8
Q
glucose is composed of how many elements and atoms ?
A
3 elements
24 atoms
9
Q
what is a molecule
A
atoms bonding in a stable arrangement
10
Q
what is a compound ?
A
a substance composed of two or more different atoms
11
Q
why can’t O2 be a compound ?
A
because it contains a single element
12
Q
atoms are composed of which three things
A
electrons protons and neutrons
13
Q
the core of an atom contains what ?
A
positively charged protons and neutrons (no charge)
14
Q
what is in the cloud of an atom ?
A
negatively charged electrons
15
Q
first shell of an atom has how many electrons ?
A
except for hydrogen, 2
16
Q
second shell of an atom has how many electrons ?
A
8 maximum
17
Q
third shell of an atom has how many electrons ?
A
8 maximum
18
Q
what is the valence shell ?
A
the outermost shell
19
Q
what value do the number of electrons in the valence shell have ?
A
valence electrons determine the chemical behavior of an atom
20
Q
when an element is chemically inert, what does that reveal about their valence shell ?
A
they are fully occupied and won’t form chemical bonds
21
Q
what is an atom’s quest in life ? (rule 1)
A
to have fully occupied valence shells
22
Q
what is the strongest of all bonds ?
A
a covalent bond which means that both atoms have 8 valence electrons now (or 2 in the case of hydrogen)
23
Q
what is an ionic bond ?
A
atom donates outer electron to another atom
eg sodium chloride
24
Q
what is the net charge of sodium and chlorine on sodium chloride ?
A
1+ on sodium atom
11+ charges and 10- charges since donated one electron
chlorine has a 1- charge since 17+ charges and 18- charges (1 electron from sodium)
25
when you place table salt in water, what happens ?
sodium chloride dissociates bc it is an ionic bond
26
why doesn't an eraser destroy itself in water ?
because it is made of covalent bonds
27
what is a solution ?
an evenly distributed mixture of 2+ compounds
28
what is a solvent ?
the primary component of a solution
29
what is a solute ?
the lesser component of a solution
30
what is the solvent of blood
water
31
what are the 3 components of blood
55% plasma (water and nutrients)
1% leukocytes
45% erythrocytes
32
where do cells get their nutrients from ?
plasma escapes from vessels into interstitial fluid
33
what is electronegativity
an atom's attraction for the electron in a chemical bond
34
what is the electronegativity of the oxygen atom ?
oxygen is very electronegative, so it pulls on electrons much more than the hydrogen atoms in an oxygen-hydrogen bond
35
what is the chemistry golden rule 2
oxygen is very electronegative
36
in water, what are the implications of oxygen's electronegativity ?
shared electrons between hydrogen and oxygen are pulled more toward oxygen, meaning there is a partial negative charge on oxygen and partial positive charge on the hydrogens
37
what are polar molecules ?
partially charged molecules created by electronegative atoms
38
what are hydrogen bonds and how are they created
bond between an electronegative atom and a hydrogen atom bonded to another electronegative atom
39
polar molecules interact with other polar molecules with what
hydrogen bonds
40
when you put your finger in water, how are you altering its structure
disrupting hydrogen bonds
41
why does glucose dissolve in water
it is polar
42
why do proteins dissolve in water?
they are polar
43
if glucose is polar, does starch also dissolve in water ?
no because it is packed into tightly dense granules.. you have to unravel them for starch to be soluble. as they unfold, they form hydrogen bonds with the water.
44
what is the gelation temperature
temperature at which starch becomes an amorphous network of starch and water (no granules)
45
why is corn starch used to thicken sauces ?
hydrogen bond with starch, less water, thickening of solution
46
do enzymes dissolve easily
yes bc they are protein
47
in the absence of ______, absorption of nutrients would be impossible
enzymes
48
why can't maltose be digested ?
we don't have an enzyme that fits it in its specific 3D structure
49
how come we can easily change an enzyme's shape ?
because its 3D shape is the result of hydrogen bonds
50
why is the pH crucial to digestion ?
bc it activates enzymes
51
why wouldn't an enzyme working in mouth work in stomach ?
the change in pH would cause it to change shape
52
what is the mouth pH
6.4 (saliva)
53
what is the stomach pH
1 (gastric juice)
54
what is the intestine pH
8 (bile and pancreatic juice)
55
what is the pH
measure of concentrations of hydrogen ions
56
with each whole number increase in pH, what changes in [H+]
concentration of hydrogen ions decreases 10 times
57
the functionality of enzymes in body and in food depends on what
the solution in which they are suspended
58
how do you explain milk going bad ?
bacteria releases acid causing milk to curdle
59
what are the four types of tissue that form organs ?
epithelial
nerve
muscle
connective tissue
60
what is epithelial tissue ?
lines tissues
61
the lining of alimentary canal is made of what ?
epithelial tissue
62
what is the role of epithelial tissue in GI tract
synthesize and excrete enzymes, absorb nutrients
63
transit time of food in GI tract?
24-72 hrs
64
what are the 3 functions of the digestive system ?
digestion, absorption, elimination
65
what are the 3 substances released by epithelial tissues ?
enzymes, hormones, mucus
66
mouth and stomach perform what kind of breakdown of food
chemical and mechanical
67
what are the 3 muscle layers in stomach
longitudinal muscle layer over circular and over diagonal sheets
68
what is chyme ?
food mixed with enzyme secretions in stomach
69
what is the qty of chyme going into the small intestine at a time
teaspoons
70
what are villi
finger-like projections in folds in small intestine
71
each villi has what sort of vessel ?
blood vessel and a lymph (lacteal) vessel
72
which part of the digestive system has a high turnover rate for its cells
small intestine
73
why is one of the first signs of malnutrition diarrhea
inability to absorb food due to loss of villi and inability to replace
74
what are the 3 digestive accessory organs
pancreas
gallbladder
liver
75
how does the liver receive nutrients ?
nutrients absorbed from all over intestines and then delivered via hepatic portal vein
76
the large intestine absorbs what
minerals and water
77
gut flora likes what nutrient
fiber
78
the nutrients of your most recent meals can be found where
blood on surface of your skin
79
food must be combined with what to move through the system ?
lubricated with fluids
80
for digestive enzymes to work, how must food be
broken down into small particles and suspended in liquid
81
what is the lumen
space within a vessel, such as the intestine
82
what is the pharynx
leads from the nose and mouth to larynx and esophagus
83
what guards the entrance to the trachea ?
epiglottis
84
what are the three parts of the small intestine
duodenum, jejunum, ileum
85
what does the appendix contain
lymph cells
86
what is digestion
Digestion is the body’s ingenious way of breaking down foods into nutrients in preparation for absorption.
87
why does evacuation of waste matter need to be done periodically ?
because it would be impractical and embarassing if it were to happen constantly
88
what is the gastrointestinal tract ?
The gastrointestinal (GI) tract is a flexible muscular tube that extends from the mouth, through the esophagus, stomach, small intestine, large intestine, and rectum to the anus.
89
where does the process of digestion begin
the mouth
90
what is a fancier word for chewing ?
mastication
91
where is the ileocecal sphincter ?
separates small and large intestine
92
what is the rectum ?
the muscular terminal part of the intestine
93
what does the gallbladder do
store bile
94
what is a bolus ?
what a mouthful of food is called after it has been chewed and swallowed
95
what is the cardiac sphincter ?
the lower esophageal sphincter
96
when you swallow, what happens in the esophagus ?
the upper sphincter opens, letting the bolus in, it slides through a hole in the diaphragm to the stomach and then the lower sphincter closes.
97
explain the main 4 parts and the role of the large intestine
The colon begins with the ascending colon rising upward toward the liver. It becomes the transverse colon as it turns and crosses the body toward the spleen. The descending colon turns downward and becomes the sigmoid colon, which extends to the rectum. Along the way, the colon mixes the intestinal contents, absorbs water and salts across the colon wall, and forms stools.
98
what kind of muscle is found in the GI tract
circular smooth muscle which allows for peristalsis
99
what is carbohydrase ?
enzyme causing hydrolysis of carbs
100
what is protease
enzyme causing hydrolysis of proteins
101
what is lipase
enzyme causing hydrolysis of fat
102
how does peristalsis work in the smooth muscle ?
inner circular muscles contract, tightening the tube and pushing the chyme forward. when they relax, the outer longitudinal muscles contract
103
explain how segmentation contractions work
unlike peristalsis, segmentation allows chyme to be moved in both directions, not just caudal, which causes a greater mixing with digestive juices, nutrients brought to intestinal lining for absorption
104
in the stomach, what is secreted ?
digestive juice (water, enzymes, and hydrochloric acid)
105
what is bile ?
an emulsifier which make the fat more soluble in digestion, allowing for enzymes to break them down
106
unlike most other nutrients, where does carbohydrate digestion begin ?
in the mouth, as salivary enzyme digests starch (amylase)
107
where does protein begin to be digested ?
in the stomach, proteins are digested due to the HCl in gastric juice
108
why does carb digestion cease in the stomach, and then start again in the small intestine ?
acid of gastric juices inactivates salivary enzyme amylase
109
when does most fat digestion start ?
in the small intestine, emulsified by bile released by the gall bladder, can be digested into smaller fragments
110
most fibre is absorbed where ?
nowhere it is excreted
111
what is the difference between facilitated diffusion and active transport ?
active transport requires energy, moving against a concentration gradient
in both cases they require carriers
112
is every part of the intestinal tract going to digest nutrients the same way
no. successive portions of the intestinal tract are specialized to absorb different nutrients
113
absorption of nutrients into the small intestine usually happens with ________ and ________
simple diffusion and active transport
114
what is the role of villi in the small intestine ?
absolutely necessary, walls wrinkled and lined with them
recognize and select the nutrients the body needs and regulate their absorption. As already described, each absorptive cell of a villus is coated with thousands of microvilli, which project from the cell’s membrane. In these microvilli, and in the membrane, lie hundreds of different kinds of enzymes and “pumps,” which recognize and act on different nutrients
115
is it true that you shouldn't combine food and eat two different foods at the same time bc the digestive system cannot handle it ?
no, false
116
what is the vascular system ?
a closed system in which blood flows continuously
117
the hepatic portal vein directs blood to __
liver
118
the hepatic vein directs blood to __
heart (drains liver)
119
what is the body's main metabolic organ
the liver
120
what is special about the liver's placement
The liver’s placement ensures that it will be first to receive the water-soluble nutrients absorbed from the GI tract. In fact, the liver has many jobs to do in preparing the absorbed nutrients for use by the body. It is the body’s most metabolically active organ.
121
nutrients leaving the digestive system via lymphatic vessels will have what pathway
lymph collects in thoracic duct and then subclavian vein where it enters the bloodstream (therefore bypasses liver)
122
what are 4 factors that affect GI function
physical immaturity
nutrition
illness
aging
123
why are probiotics good ?
because they change the condition of gut bacteria, in a way that benefits health (digestion)
124
what are prebiotics?
fibre etc that encourages the growth of bacteria
125
what is a synbiotic food product ?
one that contains pro and prebiotics
126
what is the negative feedback loop in the stomach ?
when stomach pH reaches 1.5, no more production of gastrin and therefore no more HCl released
127
what does cholecystokinin do ?
stimulates gall bladder contraction to release bile into small intestine (secreted from intestine wall)
128
what does secretin do ?
it stimulates pancreas to release bicarbonate to neutralize acidic chyme to make sure intestine stays at a slightly alkaline pH (secreted from duodenal wall)
129
what is a zymogen
an inactive precursor of an enzyme
130
why don't digestive enzymes harm the pancreas ?
the pancreas protects itself with inactive forms of the enzymes
131
Pancreatic secretions contain a mixture of enzymes to digest carbohydrate, fat, and protein. How does the pancreas know how much of each type of enzyme to provide?
Clearly, the pancreas does know what its owner has been eating, and it secretes enzyme mixtures tailored to handle the food mixtures that have been arriving recently (over the last several days). Enzyme activity changes proportionately in response to the amounts of carbohydrate, fat, and protein in the diet. If a person has been eating mostly carbohydrates, the pancreas makes and secretes mostly carbohydrases; if the person’s diet has been high in fat, the pancreas produces more lipases; and so forth. Presumably, hormones from the GI tract, secreted in response to meals, keep the pancreas informed as to its digestive tasks.
132
what is intestinal ischemia?
not enough blood flow to the digestive system
133
what are the 3 symptoms of intestinal ischemia
abdominal pain, forceful bowel movements, and blood in the stool.
134
what are the 4 parts of the colon, in order ?
ascending
transverse
descending
sigmoid
135
what is the ability of the GI tract muscles to move called ?
motility
136
where does carb digestion happen ? where does it not and why ?
carb digestion happens in mouth and in small intestine.
none in stomach bc gastric juices deactivate amylase
137
where is starch digestion most active ?
in small intestine with pancreatic enzymes
138
where does protein digestion happen most ?
stomach and small intestine
139
which fats are digested in mouth ?
hard fats which begin to melt as they reach body temperature
140
where does most fat digestion take place ?
in small intestine after it is emulsified
141
which cells in the small intestines secret mucus ?
goblet cells
142
what are the glands which secrete the intestinal juices into the small intestines ?
crypt glands
143
which nutrients in the small intestine are absorbed by simple diffusion ?
water and small lipids
144
which nutrients in the small intestine are absorbed by carrier facilitated diffusion ?
water-soluble vitamins
145
which nutrients in the small intestine are absorbed by active transport ?
glucose and amino acids
146
what causes villi to move ?
each villus lined with a thin sheet of muscle
147
where do the nutrients which go to the lymph go after ?
the heart
148
what is the difference between the lymphatic and vascular system ?
the lymphatic system has no pump . lymph circulates between cells of the body and collects into tiny vessels
149
what are the 8 vitamins produced by bacteria ?
```
biotin
folate
panthothenic acid
riboflavin
thiamin
B6
B12
K
```
150
describe the relationship between gastrin and pH
negative feedback loop
