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Biology 160 > Exam 1 > Flashcards

Exam 1 Flashcards

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1
Q

The number of ________ in an atom is always constant but the number of _______ can vary.

A

protons, electrons and neutrons

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2
Q

Mass number =

A

number of protons + neutrons

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3
Q

Atomic number =

A

number of protons

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4
Q

What are the most abundant elements found in organisms?

A

Hydrogen, carbon, nitrogen, oxygen, sodium, magnesium, phosphorous, sulfur, and chlorine

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5
Q

What is a covalent bond?

A

The sharing of electrons between atoms

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6
Q

How many bonds can carbon form?

A

4

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7
Q

How many bonds can oxygen form?

A

2

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8
Q

How many bonds can hydrogen form?

A

1

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9
Q

How many bonds can nitrogen form?

A

3 or 4

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10
Q

How many bonds can phosphorous form?

A

5

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11
Q

How many bonds can sulfur form?

A

2, 4, or 6

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12
Q

How many electrons can the third shell hold?

A

8 or 18

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13
Q

________ is the primary component of life on Earth.

A

Carbon

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14
Q

Carbon atoms in organic molecules are responsible for their overall _______.

A

shape

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15
Q

What is a nonpolar covalent bond?

A

When electrons are shared equally

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16
Q

What is a polar covalent bond?

A

When electrons are shared unequally

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17
Q

Electronegativity depends on what two factors?

A

number of protons and the distance between protons and the valence shell

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18
Q

What is the comparison of electronegativity between oxygen, nitrogen, carbon, sulfur, phosphorous, and hydrogen?

A

O>N>C-S-P-H

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19
Q

What is an ionic bond?

A

The gain or loss of an electron (due to electronegativity)

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20
Q

Water is ____.

A

polar

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21
Q

Water molecules form _______ _____.

A

hydrogen bonds

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22
Q

What are characteristics of hydrogen bonds?

A

Weak electrical attraction, no electron sharing, much weaker than covalent and ionic bonds, occurs between an H with a + charge and an atom with a - charge.

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23
Q

Why can many molecules dissolve in water?

A

Because they can form hydrogen bonds with the water molecules.

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24
Q

What shape does a water molecule have?

A

Bent

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25
Q

What are macromolecules?

A

Large, complex molecules (proteins, nucleic acids, carbohydrates, etc.)

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26
Q

A polymer is made up of _______.

A

monomers

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27
Q

Proteins are composed of ______ ______.

A

amino acids

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28
Q

What groups/atoms are in an amino acid?

A

Amino group, carboxyl group, hydrogen atom, a central carbon atom, and a side chain

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29
Q

What is an acid?

A

A molecule that can donate a proton

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30
Q

What is a base?

A

A molecule that can attract a proton

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31
Q

Does the amino group in proteins act as an acid or base?

A

base

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32
Q

Does the carboxyl group in proteins act as an acid or base?

A

acid

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33
Q

What is the side chain of glycine (Gly/G)?

A

a hydrogen atom

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34
Q

What are the characteristics of hydrophobic side chains?

A

nonpolar, does not contain O and N (except Trp)

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35
Q

What are the characteristics of hydrophilic side chains?

A

polar, have O and sometimes N, have a partial charge

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36
Q

If you see - it is an ______ side chain, if you see + it is a ______ side chain.

A

acidic, basic

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37
Q

What forms peptide bonds?

A

condensation (dehydration) reactions

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38
Q

What is a condensation (dehydration) reaction?

A

Monomer in, water out. A bond is formed and water is produced.

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39
Q

A peptide bond is similar to a _______ bond.

A

double

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40
Q

What group is on the N-terminus of a protein?

A

Amino group

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41
Q

What group is on the C-terminus of a protein?

A

Carboxyl group

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42
Q

What is the formula for a carboxyl group?

A

COOH

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43
Q

What is the formula for an amino group?

A

NH2

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44
Q

Proteins move because single bonds ________.

A

rotate

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45
Q

How many amino acids does a peptide (oligopeptide) contain?

A

less than 50

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46
Q

How many amino acids does a protein contain?

A

50 or more

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47
Q

A polypeptide can be a ______ or ______.

A

peptide, protein

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48
Q

What is the primary structure of a protein?

A

a unique sequence of amino acids

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49
Q

Changes (due to a mutation) in the primary structure of a protein can affect _______ _______.

A

protein function

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50
Q

What is the secondary structure of a protein?

A

Three-dimensional form of short amino acid sequences (a-helix or B-pleated sheets)

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51
Q

What type of bonding creates the secondary structure of protein?

A

Hydrogen bonding

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52
Q

What type of bonding forms the tertiary structure of proteins?

A

Hydrogen bonds, ionic bonds, hydrophobic interactions, and disulfide bonds

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53
Q

What is the tertiary structure of proteins?

A

A three-dimensional form of proteins comprised of multiple a-helices or B-pleated sheets

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54
Q

What is the quaternary structure of proteins?

A

When two or more proteins form a complex

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55
Q

What types of bonds form the quaternary structure of proteins?

A

Hydrogen bonds, ionic bonds, hydrophobic interactions, and disulfide bonds (same as tertiary structure)

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56
Q

What type of R group does cysteine have?

A

A sulfhydryl group (CH2-SH)

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57
Q

What is a dimer?

A

A complex of two proteins

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58
Q

What is a tetramer?

A

A complex of 4 proteins

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59
Q

How are proteins structures determined?

A

X-ray crystallography

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60
Q

What is the overall shape of a protein determined by?

A

Its primary structure

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61
Q

Structure defines ______.

A

function

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62
Q

_______ are the most versatile large molecules in the cell.

A

Proteins

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63
Q

What is the formation of the tertiary and quaternary structure of proteins called?

A

Protein folding

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64
Q

Protein folding is often _______.

A

Spontaneous

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65
Q

A folded molecule is often more __________ _____ than the unfolded molecule.

A

energetically stable

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66
Q

What is an unfolded protein called?

A

a denatured protein

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67
Q

What proteins help some proteins fold correctly in cells?

A

Chaperones

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68
Q

Why do high temperatures lead to protein unfolding?

A

High temperatures break bonds

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69
Q

What environmental conditions determine protein folding?

A

Temperature, ion concentration, and pH

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70
Q

What breaks proteins back down into amino acids?

A

Hydrolysis (water in, monomer out)

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71
Q

What monomers comprise nucleic acids?

A

nucleotides

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72
Q

What makes up a nucleotide?

A

Phosphate group, nitrogenous base, and a 5-carbon sugar

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73
Q

Which carbon in deoxyribose is lacking an oxygen atom compared to ribose?

A

C2

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74
Q

Which is larger: purine or pyrimidines?

A

Purines

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75
Q

Which nitrogenous bases are purines?

A

Guanine and adenine

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76
Q

Which nitrogenous bases are pyrimidines?

A

Cytosine, Uracil, and Thymine

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77
Q

The nitrogenous is bonded to which carbon in the 5-carbon sugar?

A

C1

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78
Q

What is the abbreviation for monophosphates, diphosphates, and triphosphates?

A

_MP, _DP, _TP

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79
Q

What goes in front of nucleotides with deoxyribose?

A

the letter “d”

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80
Q

What forms nucleic acids (type of linkage)?

A

Phosphodiester linkage

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81
Q

How is a phosphodiester linkage formed?

A

A condensation reaction between C3 of the 5-carbon sugar and phosphate

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82
Q

What is the 5’ end?

A

Then end with an unlinked 5’ phosphate

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83
Q

What is the 3’ end?

A

The end with an unlinked 3’ hydroxyl

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84
Q

What direction are nucleotide sequences written in?

A

5 ——> 3

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85
Q

What is used for DNA and RNA synthesis?

A

Nucleoside triphosphates

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86
Q

Are DNA and RNA acids or bases?

A

acids

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87
Q

What type of charge does DNA and RNA have?

A

A negative charge

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88
Q

What is the secondary structure of DNA stabilized by?

A

hydrogen bonding

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89
Q

What if the half life of DNA?

A

521 years

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90
Q

What is the secondary structure of RNA?

A

a double stranded region forming a helix, and and single stranded region forming a loop

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91
Q

What is the tertiary structure of RNA?

A

When secondary structures fold into more complex shapes

92
Q

What can RNA function as?

A

a catalytic molecule

93
Q

What are ribozymes?

A

Enzyme-like RNAs

94
Q

What type of carbohydrate is sugar?

A

sucrose

95
Q

What type of carbohydrate are wood and cotton?

A

cellulose

96
Q

Milk contains what type of carbohydrate?

A

lactose

97
Q

What is a carbohydrate?

A

Organic compounds with the empirical formula (CH20)n

98
Q

What functional groups are found in carbohydrates?

A

carbonyl group, hydroxyl group, and a hydrogen atom

99
Q

What is a monosaccharide?

A

simple sugars, monomers

100
Q

What are examples of monosaccharides?

A

glucose, galactose, fructose, ribose, and deoxyribose

101
Q

What are disaccharides made up of?

A

two monomers

102
Q

What is sucrose?

A

glucose+fructose

103
Q

What is lactose?

A

glucose+galactose

104
Q

What are oligosaccharides?

A

polymers made from 3-10 monosaccharides

105
Q

What is a polysaccharide?

A

A polymer made from many monosaccharides

106
Q

What are examples of polysaccharides?

A

starch, glycogen, cellulose, chitin, and peptidoglycan

107
Q

What do monosaccharides differ in?

A

The number of carbon atoms present, and the arrangement and number of their hydroxyl groups

108
Q

What is a monosaccharide with 3 carbons called?

A

a triose

109
Q

What is a monosaccharide with 5 carbons called?

A

a pentose

110
Q

What is a monosaccharide with 6 carbons called?

A

hexose

111
Q

What do glucose and galactose differ in?

A

The configuration of their hydroxyl groups at C4 (glucose = OH over H, galactose = OH under H)

112
Q

Hexokinase will interact with _______ but never _______.

A

glucose, galactose

113
Q

What do many monosaccharides form in aqueous solutions?

A

ring structures

114
Q

a-glucose and B- glucose differ in?

A

The configuration of their hydroxyl groups at C1 (a-glucose = OH on bottom, B-glucose = OH on top)

115
Q

Are carbohydrates hydrophobic or hydrophilic?

A

hydrophilic

116
Q

What produces polysaccharides?

A

The condensation of monosaccharides

117
Q

What type of linkage forms polysaccharides?

A

glycosidic linkage (condensation reaction)

118
Q

When B-galactose and B-glucose link together, ______ is flipped.

A

B-glucose

119
Q

What forms maltose?

A

a-glycosidic linkage

120
Q

What forms lactose?

A

B-glycosidic linkage

121
Q

What breaks down polysaccharides?

A

hydrolysis ( water in, monomer out)

122
Q

What polysaccharides are made of glucose?

A

glycogen, starch, and cellulose

123
Q

Cellulose =

A

(B1 –> 4) linked glucose units

124
Q

What do glycogen and starch do?

A

store and provide energy in cells

125
Q

Why do glycogen and starch provide energy in cells?

A

They have a lot of C-H and C-C bond, high potential energy bonds. When they are broken, energy is released.

126
Q

Glycogen is a _______ molecule.

A

Branched

127
Q

Which is more branched: glycogen or starch?

A

glycogen

128
Q

Starch is produced by ________, while glycogen is produced by ________.

A

Plants, animals

129
Q

Where is glycogen stored?

A

In the liver

130
Q

What does an organism do when it need energy?

A
  1. glycogen or starch are hydrolyzed to glucose
  2. cells break down glucose through a series of reactions (respiration)
  3. released energy is captured through synthesis of ATP (adenosine triphosphate)
131
Q

What forms cells walls?

A

cellulose

132
Q

What makes up a bacterial cell wall?

A

peptidoglycan

133
Q

What makes up fungi cell walls and insect exoskeletons?

A

Chitin

134
Q

What are characteristics/ roles of a cell wall?

A
  1. outside of the plasma membrane
  2. very rigid and cage-like
  3. responsible for cell shape
  4. prevents osmotic bursting
  5. protects from other organisms
135
Q

In a cell wall, many ______ molecules aligned along each other are joined by ______ ______.

A

cellulose, hydrogen bonding

136
Q

What is the most abundant molecule on earth?

A

cellulose

137
Q

In fungi cell walls and insect exoskeletons, many _______ molecules are aligned along each other and joined by ______ _____.

A

chitin, hydrogen bonding

138
Q

What is chitin similar to? What type of linkage does it have?

A

glucose, B1–>4 glycosidic linkage

139
Q

What type of linkage does peptidoglycan have? What bonds hold it together?

A

B1–>4 glycosidic linkage, hydrogen bonds

140
Q

What carbohydrates are structural carbohydrates?

A

cellulose, chitin, peptidoglycan

141
Q

What do carbohydrates do? (5 things)

A
  1. store chemical energy
  2. provide fibrous structural materials
  3. serve as precursors to larger molecules
  4. indicate cell identity
  5. make proteins more stable
142
Q

Which carbohydrates serve as precursors to larger molecules?

A

glucose, galactose, fructose

143
Q

Which carbohydrates indicate cell identity and make proteins more stable?

A

glycoproteins

144
Q

How do glycoproteins indicate cell identity?

A

They display informations on the outer surface of cells

145
Q

What is each spike on a spike protein made of?

A

Three intertwined proteins

146
Q

What are lipids?

A

Carbon containing compounds found in organisms.

147
Q

What are lipids mostly made of?

A

C-C and C-H bonds

148
Q

Are lipids polar or nonpolar?

A

nonpolar

149
Q

Are lipids hydrophobic or hydrophilic?

A

Largely hydrophobic

150
Q

What are the three most important types of lipids found in cells?

A

Triacylglycerols, phospholipids, and steroids

151
Q

What do tracylglycerols do?

A

Store energy through fats and oils

152
Q

What do phospholipids do?

A

Make membranes

153
Q

What do steroids do?

A

Found in membranes, vitamins, and hormones

154
Q

What are the key building blocks of lipids?

A

Fatty acids

155
Q

What do fatty acids contain?

A

A carboxyl group and a hydrocarbon chain

156
Q

Fatty acids are __________.

A

Amphipathic ( have polar and nonpolar parts)

157
Q

Amphipathic salts of fatty acids spontaneously form ________.

A

micelles

158
Q

Does a saturated fatty acid have double bonds?

A

No

159
Q

Does an unsaturated fatty acid have double bonds?

A

yes

160
Q

What do double bonds in fatty acids cause?

A

Kinks in the tails

161
Q

What does monounsaturated mean?

A

one double bond

162
Q

What does polyunsaturated mean?

A

many double bonds

163
Q

What does a triacylglycerol consist of?

A

A glycerol linked by ester linkages to three fatty acids

164
Q

How do fats form?

A

Via dehydration reacts (Ester linkages)

165
Q

What are tricylglycerols from animals called? Plants?

A

fats, oils

166
Q

What does the melting point of triacylglycerols depend on?

A

The number of double bonds in their tails

167
Q

Are oils saturated or unsaturated?

A

unsaturated

168
Q

Are fats saturated or unsaturated?

A

saturated

169
Q

What is the function of oils in plants?

A

Serve as an energy reserve in seeds

170
Q

What is a phospholipid made of?

A

glycerol, two fatty acids, and a polar group (has phosphate)

171
Q

Amphipathic phospholipids spontaneously form ______ ______.

A

lipid bilayers

172
Q

Eukaryotic cells have many _________.

A

membranes

173
Q

Phospholipids bilayers have selective ________.

A

permeability

174
Q

What types of molecules have the highest permeability?

A

Small, nonpolar molecules

175
Q

What types of molecules have the lowest permeability?

A

Ions

176
Q

Do lipid bilayers with short and unsaturated hydrocarbon tails have higher or lower permeability and fluidity?

A

higher

177
Q

Do lipid bilayers with long and saturated hydrocarbon tails have higher or lower permeability and fluidity?

A

lower

178
Q

What type of structure does a steroid have?

A

a bulky, four-ring structure

179
Q

What is the most abundant steroid in animals?

A

cholesterol

180
Q

What is the function of cholesterol?

A

reduces membrane permeability, precursor of vitamin D, and a precursor for several hormones

181
Q

Cholesterol does not exist in ______.

A

plants

182
Q

What does the quickness of molecule movement across membranes depend on?

A

The structure of fatty acid tails, the number of cholesterol molecules in the bilayer, and temperature

183
Q

How does temperature affect permeability?

A

Higher temperature = more movement

184
Q

Phospholipids are in _______ ______ motion.

A

constant lateral

185
Q

What do plasma membranes allow for?

A

For cells to create an internal environment that is much different from an external one.

186
Q

What do other cell membranes allow for?

A

compartmentalization

187
Q

What does the existence of membrane lead to the formation of?

A

concentration gradients

188
Q

What is a concentration gradient?

A

A difference in solute concentrations across a barrier

189
Q

Why do molecules cross membranes?

A

Molecules and ions move randomly (diffusion), net movement from high-concentration regions to low concentration regions, spontaneous process (requires no energy input)

190
Q

When does equilibrium occur?

A

When the molecules or ions are randomly distributes (no more net movement)

191
Q

How does water move across lipid bilayers?

A

Water moves from regions of low solute concentration to regions of high concentration

192
Q

What is osmosis?

A

The movement of water across a selectively permeable membrane

193
Q

What is passive diffusion?

A

Movement of molecules across membranes along their concentration gradients

194
Q

What is a hypotonic solution to outside?

A

When there is less of a solute within a cell and more outside

195
Q

What is a hypertonic solution to outside?

A

When there is more of a solute within a cell and less outside

196
Q

What is an isotonic solution to outside?

A

When the solute is evenly distributed

197
Q

What happens when a cell is hypotonic to the outside?

A

The cell shrinks

198
Q

What happens when a cell is hypertonic to the outside?

A

It swells with water and bursts

199
Q

What is a peripheral membrane protein?

A

The portion of the protein on the outside of the membrane

200
Q

What is an integral membrane protein?

A

The portion of a protein inside of the membrane

201
Q

What allows biologists to view membrane proteins?

A

Freeze-fracture preparations

202
Q

Proteins can be ________.

A

amphipathic

203
Q

What proteins can integrate into lipid layers?

A

Amphipathic proteins

204
Q

What are the two mechanisms of membrane transport?

A

Diffusion and facilitated diffusion (passive diffusion)

205
Q

What is aquaporin?

A

facilitated diffusion, water channel, passive transport along its electrochemical gradient, allows for osmosis

206
Q

What is active transport?

A

Transport against the electrochemical gradient

207
Q

What do channel proteins do?

A

Aid in facilitated diffusion

208
Q

What does each channel protein have?

A

A specific structure that allows only a particular type of ion or small molecule to pass through it

209
Q

What direction(s) can a molecule move through a channel?

A

Both directions

210
Q

What do gated proteins do?

A

Regulate movement through membrane channels: open or close in response to a signal

211
Q

What are the two types of gated proteins?

A

Voltage-gated and ligand-gated (extracellular ligand)

212
Q

How does a potassium channel work?

A

When the inside of the membrane is negatively charges relative to the outside, the channel is closed (gate blocks ions from entering channel). If membrane charge asymmetry is reversed, channel opens (filter only allows K+ ions to pass).

213
Q

How do carrier proteins work?

A

They change shape during the transport process, a glucose transporter named GLUT-1 increases permeability to glucose. Carrier proteins are slower than channels.

214
Q

What are the steps of glucose diffusion with GLUT-1?

A
  1. Unbound protein outside of the cell
  2. glucose binding
  3. conformational change
  4. release
215
Q

Is the movement of substances through channel and carriers passive or active?

A

Passive

216
Q

What is passive transport powered by?

A

diffusion along an electrochemical gradient

217
Q

What factors affect facilitated diffusion?

A

The difference in the concentration of solutes between the two sides of the membranes, the number of channels/carrier proteins available on the plasma membrane, the affinity of the channel/carrier protein for its substrate molecule

218
Q

What are pumps?

A

Membrane proteins that transport molecules across the membrane against the electrochemical gradient. Requires energy in the form of ATP

219
Q

What are the steps of Na+/K+ pump?

A
  1. unbound protein
  2. sodium binding
  3. shape change
  4. release
  5. unbound protein
  6. potassium binding
  7. shape change
  8. release
220
Q

What percentage of ATP generated by your body is used by the Na+/K+ pump?

A

30%

221
Q

What does the Na+/K= pump do?

A

It establishes an electrochemical gradient in animal cells

222
Q

What does an H+ pump do?

A

Establish an electrochemical gradient in bacterial, yeast, and plant cells

223
Q

What does the electrochemical gradient allow for?

A

secondary active transport, or co-transport

224
Q

What are antiporters?

A

Channel that move two ions in opposite directions

225
Q

What are symporters?

A

Channels that move two ions in the same directions

Biology 160 (4 decks)

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