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BIOL 203 > Lesson 3 > Flashcards

Lesson 3 Flashcards

1
Q

what is the percentage of elements of the periodic table essential for life ?

A

25%

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2
Q

do we also share chemical similarities with nonliving objects ?

A

no mostly made up of different elements

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3
Q

what is the smallest unit of matter

A

the atom

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4
Q

what is matter

A

anything that takes up space

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5
Q

the human body is composed of what

A

matter

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6
Q

how many elements is the human body composed of ?

A

about 23

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7
Q

water is composed of how many elements and atoms ?

A

2 elements

3 atoms

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8
Q

glucose is composed of how many elements and atoms ?

A

3 elements

24 atoms

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9
Q

what is a molecule

A

atoms bonding in a stable arrangement

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10
Q

what is a compound ?

A

a substance composed of two or more different atoms

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11
Q

why can’t O2 be a compound ?

A

because it contains a single element

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12
Q

atoms are composed of which three things

A

electrons protons and neutrons

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13
Q

the core of an atom contains what ?

A

positively charged protons and neutrons (no charge)

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14
Q

what is in the cloud of an atom ?

A

negatively charged electrons

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15
Q

first shell of an atom has how many electrons ?

A

except for hydrogen, 2

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16
Q

second shell of an atom has how many electrons ?

A

8 maximum

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17
Q

third shell of an atom has how many electrons ?

A

8 maximum

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18
Q

what is the valence shell ?

A

the outermost shell

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19
Q

what value do the number of electrons in the valence shell have ?

A

valence electrons determine the chemical behavior of an atom

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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

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21
Q

what is an atom’s quest in life ? (rule 1)

A

to have fully occupied valence shells

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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)

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23
Q

what is an ionic bond ?

A

atom donates outer electron to another atom

eg sodium chloride

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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)

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25
Q

when you place table salt in water, what happens ?

A

sodium chloride dissociates bc it is an ionic bond

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26
Q

why doesn’t an eraser destroy itself in water ?

A

because it is made of covalent bonds

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27
Q

what is a solution ?

A

an evenly distributed mixture of 2+ compounds

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28
Q

what is a solvent ?

A

the primary component of a solution

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29
Q

what is a solute ?

A

the lesser component of a solution

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30
Q

what is the solvent of blood

A

water

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31
Q

what are the 3 components of blood

A

55% plasma (water and nutrients)
1% leukocytes
45% erythrocytes

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32
Q

where do cells get their nutrients from ?

A

plasma escapes from vessels into interstitial fluid

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33
Q

what is electronegativity

A

an atom’s attraction for the electron in a chemical bond

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34
Q

what is the electronegativity of the oxygen atom ?

A

oxygen is very electronegative, so it pulls on electrons much more than the hydrogen atoms in an oxygen-hydrogen bond

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35
Q

what is the chemistry golden rule 2

A

oxygen is very electronegative

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36
Q

in water, what are the implications of oxygen’s electronegativity ?

A

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

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37
Q

what are polar molecules ?

A

partially charged molecules created by electronegative atoms

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38
Q

what are hydrogen bonds and how are they created

A

bond between an electronegative atom and a hydrogen atom bonded to another electronegative atom

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39
Q

polar molecules interact with other polar molecules with what

A

hydrogen bonds

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40
Q

when you put your finger in water, how are you altering its structure

A

disrupting hydrogen bonds

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41
Q

why does glucose dissolve in water

A

it is polar

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42
Q

why do proteins dissolve in water?

A

they are polar

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43
Q

if glucose is polar, does starch also dissolve in water ?

A

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.

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44
Q

what is the gelation temperature

A

temperature at which starch becomes an amorphous network of starch and water (no granules)

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45
Q

why is corn starch used to thicken sauces ?

A

hydrogen bond with starch, less water, thickening of solution

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46
Q

do enzymes dissolve easily

A

yes bc they are protein

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47
Q

in the absence of ______, absorption of nutrients would be impossible

A

enzymes

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48
Q

why can’t maltose be digested ?

A

we don’t have an enzyme that fits it in its specific 3D structure

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49
Q

how come we can easily change an enzyme’s shape ?

A

because its 3D shape is the result of hydrogen bonds

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50
Q

why is the pH crucial to digestion ?

A

bc it activates enzymes

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51
Q

why wouldn’t an enzyme working in mouth work in stomach ?

A

the change in pH would cause it to change shape

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52
Q

what is the mouth pH

A

6.4 (saliva)

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53
Q

what is the stomach pH

A

1 (gastric juice)

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54
Q

what is the intestine pH

A

8 (bile and pancreatic juice)

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55
Q

what is the pH

A

measure of concentrations of hydrogen ions

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56
Q

with each whole number increase in pH, what changes in [H+]

A

concentration of hydrogen ions decreases 10 times

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57
Q

the functionality of enzymes in body and in food depends on what

A

the solution in which they are suspended

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58
Q

how do you explain milk going bad ?

A

bacteria releases acid causing milk to curdle

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59
Q

what are the four types of tissue that form organs ?

A

epithelial
nerve
muscle
connective tissue

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60
Q

what is epithelial tissue ?

A

lines tissues

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61
Q

the lining of alimentary canal is made of what ?

A

epithelial tissue

62
Q

what is the role of epithelial tissue in GI tract

A

synthesize and excrete enzymes, absorb nutrients

63
Q

transit time of food in GI tract?

A

24-72 hrs

64
Q

what are the 3 functions of the digestive system ?

A

digestion, absorption, elimination

65
Q

what are the 3 substances released by epithelial tissues ?

A

enzymes, hormones, mucus

66
Q

mouth and stomach perform what kind of breakdown of food

A

chemical and mechanical

67
Q

what are the 3 muscle layers in stomach

A

longitudinal muscle layer over circular and over diagonal sheets

68
Q

what is chyme ?

A

food mixed with enzyme secretions in stomach

69
Q

what is the qty of chyme going into the small intestine at a time

A

teaspoons

70
Q

what are villi

A

finger-like projections in folds in small intestine

71
Q

each villi has what sort of vessel ?

A

blood vessel and a lymph (lacteal) vessel

72
Q

which part of the digestive system has a high turnover rate for its cells

A

small intestine

73
Q

why is one of the first signs of malnutrition diarrhea

A

inability to absorb food due to loss of villi and inability to replace

74
Q

what are the 3 digestive accessory organs

A

pancreas
gallbladder
liver

75
Q

how does the liver receive nutrients ?

A

nutrients absorbed from all over intestines and then delivered via hepatic portal vein

76
Q

the large intestine absorbs what

A

minerals and water

77
Q

gut flora likes what nutrient

A

fiber

78
Q

the nutrients of your most recent meals can be found where

A

blood on surface of your skin

79
Q

food must be combined with what to move through the system ?

A

lubricated with fluids

80
Q

for digestive enzymes to work, how must food be

A

broken down into small particles and suspended in liquid

81
Q

what is the lumen

A

space within a vessel, such as the intestine

82
Q

what is the pharynx

A

leads from the nose and mouth to larynx and esophagus

83
Q

what guards the entrance to the trachea ?

A

epiglottis

84
Q

what are the three parts of the small intestine

A

duodenum, jejunum, ileum

85
Q

what does the appendix contain

A

lymph cells

86
Q

what is digestion

A

Digestion is the body’s ingenious way of breaking down foods into nutrients in preparation for absorption.

87
Q

why does evacuation of waste matter need to be done periodically ?

A

because it would be impractical and embarassing if it were to happen constantly

88
Q

what is the gastrointestinal tract ?

A

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
Q

where does the process of digestion begin

A

the mouth

90
Q

what is a fancier word for chewing ?

A

mastication

91
Q

where is the ileocecal sphincter ?

A

separates small and large intestine

92
Q

what is the rectum ?

A

the muscular terminal part of the intestine

93
Q

what does the gallbladder do

A

store bile

94
Q

what is a bolus ?

A

what a mouthful of food is called after it has been chewed and swallowed

95
Q

what is the cardiac sphincter ?

A

the lower esophageal sphincter

96
Q

when you swallow, what happens in the esophagus ?

A

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
Q

explain the main 4 parts and the role of the large intestine

A

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
Q

what kind of muscle is found in the GI tract

A

circular smooth muscle which allows for peristalsis

99
Q

what is carbohydrase ?

A

enzyme causing hydrolysis of carbs

100
Q

what is protease

A

enzyme causing hydrolysis of proteins

101
Q

what is lipase

A

enzyme causing hydrolysis of fat

102
Q

how does peristalsis work in the smooth muscle ?

A

inner circular muscles contract, tightening the tube and pushing the chyme forward. when they relax, the outer longitudinal muscles contract

103
Q

explain how segmentation contractions work

A

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
Q

in the stomach, what is secreted ?

A

digestive juice (water, enzymes, and hydrochloric acid)

105
Q

what is bile ?

A

an emulsifier which make the fat more soluble in digestion, allowing for enzymes to break them down

106
Q

unlike most other nutrients, where does carbohydrate digestion begin ?

A

in the mouth, as salivary enzyme digests starch (amylase)

107
Q

where does protein begin to be digested ?

A

in the stomach, proteins are digested due to the HCl in gastric juice

108
Q

why does carb digestion cease in the stomach, and then start again in the small intestine ?

A

acid of gastric juices inactivates salivary enzyme amylase

109
Q

when does most fat digestion start ?

A

in the small intestine, emulsified by bile released by the gall bladder, can be digested into smaller fragments

110
Q

most fibre is absorbed where ?

A

nowhere it is excreted

111
Q

what is the difference between facilitated diffusion and active transport ?

A

active transport requires energy, moving against a concentration gradient

in both cases they require carriers

112
Q

is every part of the intestinal tract going to digest nutrients the same way

A

no. successive portions of the intestinal tract are specialized to absorb different nutrients

113
Q

absorption of nutrients into the small intestine usually happens with ________ and ________

A

simple diffusion and active transport

114
Q

what is the role of villi in the small intestine ?

A

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
Q

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 ?

A

no, false

116
Q

what is the vascular system ?

A

a closed system in which blood flows continuously

117
Q

the hepatic portal vein directs blood to __

A

liver

118
Q

the hepatic vein directs blood to __

A

heart (drains liver)

119
Q

what is the body’s main metabolic organ

A

the liver

120
Q

what is special about the liver’s placement

A

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
Q

nutrients leaving the digestive system via lymphatic vessels will have what pathway

A

lymph collects in thoracic duct and then subclavian vein where it enters the bloodstream (therefore bypasses liver)

122
Q

what are 4 factors that affect GI function

A

physical immaturity
nutrition
illness
aging

123
Q

why are probiotics good ?

A

because they change the condition of gut bacteria, in a way that benefits health (digestion)

124
Q

what are prebiotics?

A

fibre etc that encourages the growth of bacteria

125
Q

what is a synbiotic food product ?

A

one that contains pro and prebiotics

126
Q

what is the negative feedback loop in the stomach ?

A

when stomach pH reaches 1.5, no more production of gastrin and therefore no more HCl released

127
Q

what does cholecystokinin do ?

A

stimulates gall bladder contraction to release bile into small intestine (secreted from intestine wall)

128
Q

what does secretin do ?

A

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
Q

what is a zymogen

A

an inactive precursor of an enzyme

130
Q

why don’t digestive enzymes harm the pancreas ?

A

the pancreas protects itself with inactive forms of the enzymes

131
Q

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?

A

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
Q

what is intestinal ischemia?

A

not enough blood flow to the digestive system

133
Q

what are the 3 symptoms of intestinal ischemia

A

abdominal pain, forceful bowel movements, and blood in the stool.

134
Q

what are the 4 parts of the colon, in order ?

A

ascending
transverse
descending
sigmoid

135
Q

what is the ability of the GI tract muscles to move called ?

A

motility

136
Q

where does carb digestion happen ? where does it not and why ?

A

carb digestion happens in mouth and in small intestine.

none in stomach bc gastric juices deactivate amylase

137
Q

where is starch digestion most active ?

A

in small intestine with pancreatic enzymes

138
Q

where does protein digestion happen most ?

A

stomach and small intestine

139
Q

which fats are digested in mouth ?

A

hard fats which begin to melt as they reach body temperature

140
Q

where does most fat digestion take place ?

A

in small intestine after it is emulsified

141
Q

which cells in the small intestines secret mucus ?

A

goblet cells

142
Q

what are the glands which secrete the intestinal juices into the small intestines ?

A

crypt glands

143
Q

which nutrients in the small intestine are absorbed by simple diffusion ?

A

water and small lipids

144
Q

which nutrients in the small intestine are absorbed by carrier facilitated diffusion ?

A

water-soluble vitamins

145
Q

which nutrients in the small intestine are absorbed by active transport ?

A

glucose and amino acids

146
Q

what causes villi to move ?

A

each villus lined with a thin sheet of muscle

147
Q

where do the nutrients which go to the lymph go after ?

A

the heart

148
Q

what is the difference between the lymphatic and vascular system ?

A

the lymphatic system has no pump . lymph circulates between cells of the body and collects into tiny vessels

149
Q

what are the 8 vitamins produced by bacteria ?

A 
biotin
folate
panthothenic acid 
riboflavin
thiamin 
B6
B12
K
150
Q

describe the relationship between gastrin and pH

A

negative feedback loop

BIOL 203 (11 decks)

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