exam 1 Flashcards
1
Q
what is a Cation?
A
A positively charged ion. it has more protons than electrons
2
Q
What is an Anion?
A
A negatively charged ion. It has more electrons than protons
3
Q
what is an atom?
A
the smallest unit of chemical elements
4
Q
what is an ion?
A
atoms with charges
5
Q
what is a molecule?
A
2 or more atoms that are bonded to eachother
6
Q
what is a covalent bond?
A
a bond between atoms where electrons are shared
7
Q
what is a non polar covalent bond?
A
a bond between atoms where electrons are shared equally
8
Q
are non polar covalent bonds hydrophobic or hydrophilic?
A
hydrophobic, they do NOT like water
9
Q
are polar covalent molecules hydrophobic or hydrophilic?
A
hydrophilic, they like water
10
Q
what is a polar covalent bond?
A
a bond between atoms in a molecule where electrons are unequally shared
11
Q
what is an ionic bond?
A
a bond between atoms where one atom donates electrons to the other
12
Q
out of covalent, ionic, and hydrogen bonds, which is the weakest?
A
hydrogen bond
13
Q
what type of bonding is used by the nitrogenous bases in DNA?
A
hydrogen bond
14
Q
why are the hydrogen bonds in DNA so strong when hydrogen bonds are weak?
A
because there are so many along the double helix of DNA
15
Q
what is bonded with hydrogen bonds?
A
molecules are bonded to molecules
16
Q
what is bonded with ionic bonds?
A
atoms are bonded to atoms to form molecules
17
Q
what is a hydrogen bond?
A
the weak attraction of H to a nearby O, N, or F
18
Q
what is a basic solution?
A
a solution with OH- > H+
19
Q
what is an acidic solution?
A
a solution with H+ > OH-
20
Q
what do you need to make a solution?
A
a solute and a solvent
21
Q
what is a solution with a neutral PH?
A
OH- = H+ in a solution
22
Q
what makes a solution either acidic or basic?
A
the molecules within the solution are able to release either OH- or H+ ions
23
Q
what contributes to changes in PH?
A
H+ concentration
24
Q
what does the PH scale represent?
A
the H+ concentration in a solution
25
what is neutral, acidic, and basic on the ph scale?
<7 is acidic, 7 is neutral, and >7 is basic
26
what is the formula for calculating PH?
PH = -log(H+)
27
what is a buffer?
any substance that moderates changes in PH
28
what is HCO3-?
bicarbonate (a buffer)
29
what is acidosis?
a condition where blood PH becomes too acidic
30
what is the correction for acidic blood?
HCO3- + H+ > H2CO3 > CO2 + H20
31
what is the correction for blood that is too basic?
H2CO3 > HCO3- + H+
32
what are monosaccharides?
simple sugars (carbohydrate monomers) / single sugar
33
what are pentose sugars and what are examples of pentoses?
5 carbon sugars. ribose and deoxyribose
34
what are hexoses and what are examples of them?
6 carbon sugars. fructose, glucose, and galactose
35
what are the most common simple sugars?
5 carbon and 6 carbon sugars
36
what type of sugars are DNA and RNA made of?
5 carbon sugars
37
what is a disaccharide?
2 carbohydrate molecules joined together to form a larger structure
38
how are disaccharides formed?
monosaccharides (glucose and another monosaccharide) are joined together by dehydration synthesis
39
what is dehydration synthesis?
monomers joined together by removing H2O
| monomer1)OH---HO(monomer2) = (monomer1)O(monomer2
40
what type of bond is formed in a dehydration synthesis?
covalent bond
41
what are polysaccharides?
complex sugars (many monosaccharides join to form polysaccharides)
42
what is glycogen?
a polysaccharide produced by the liver released during times when an increase in blood sugar level is needed
43
what type of saccharide is starch?
polysaccharide
44
what is hydrolysis?
splitting molecules with H2O
45
what is required for hydrolysis to occur?
water and an enzyme
46
what type of lipids are fat and oil?
triglycerides
47
are triglycerides polymers or monomers?
polymers
48
what are triglycerides composed of?
glycerol and 3 fatty acid chain(s)
49
what is the difference between monoglycerides, diglycerides, and triglycerides?
monoglycerides have one fatty acid chain attached to glycerol
diglycerides have 2 fatty acid chains attached to glycerol
triglycerides have 3 fatty acid chains attached to glycerol
50
what type of molecules are fatty acid chains?
hydrocarbons
51
are hydrocarbons polar or non polar?
non polar
52
what is the difference in molecular structure of saturated and unsaturated fatty acid chains?
unsaturated has double bonded carbons and less hydrogen monounsaturated has one double bond and polyunsaturated has multiple double bonds
53
what does a phospholipid consist of?
glycerol with 2 fatty acid chains and a phosphate group attached to it
54
how do phospholipids interact with water?
the head is hydrophilic and the non polar tails are hydrophobic
55
what is the primary source of steroids within the body?
cholesterol
56
how many linked carbon rings make up a molecule of cholesterol?
4
57
are proteins polymers or monomers?
polymers
58
what are the building blocks of proteins?
amino acids
59
how many different types of amino acids make up protein?
20 different types
60
draw an amino acid structure
61
what is a peptide?
a bond that links amino acids together
62
what is a dipeptide?
2 amino acids held together by a peptide bond
63
what type of bond is a peptide bond?
covalent bond
64
how are amino acids bonded to one another?
dehydration synthesis
65
how many amino acids are within oligopeptides?
2-9 amino acids
66
how many amino acids are within a polypeptide?
10-100 amino acids
67
how many amino acids are required to be considered a protein?
>100
68
what is a primary protein structure?
a linear sequence of amino acids joined by peptide bonds
69
what is a secondary protein structure?
H bonds change the linear shape of the primary protein structure to form secondary protein structure
70
what are the different shapes of secondary protein structures?
alpha / helix (like those found in DNA)
| pleated \/\/\/\/\/\/\
71
what is a tertiary protein structure?
a secondary protein structure folded into a 3D structure
72
how are tertiary protein structures held together?
different types of bonding:
| hydrogen bonds, ionic bonds, ionic attraction and repulsion, and disulfide bonds
73
what are the active sites in tertiary protein structures?
the open pockets within the tertiary structure
74
what are quaternary protein structures?
2 or more tertiary structures combined
75
hemoglobin and collagen fiber are examples of what type of protein structure?
quaternary
76
what are the monomers or subunits of DNA?
nucleotides
77
what are the components of nucleic acids?
```
*Pentose (5 carbon sugar):
DNA = deoxyribose
RNA = ribose
*nitrogenous bases:
Purine and pyrimidine
*phosphate group
```
78
what is the difference between ribose and deoxyribose?
ribose sugar contains OH on the bottom of the pentose structure and deoxyribose contains an H at the bottom of the pentose
79
what are purines?
nitrogenous bases Adenine(A) and Guanine(G)
80
what are pyrimidines?
nitrogenous bases Cytosine(C) Thymine(T) and Uracil(U)
81
what are the types of nucleic acid?
deoxyribonucleic acid and ribonucleic acid
82
in DNA which bases pair with one another?
Guanine-Cytocine and Thymine-Adenine
83
in RNA what has the base Thymine been replaced with?
Uracil
84
what does the base Uracil pair with ?
Adenine
85
what is intracellular fluid (ICF)?
fluid within a cell
86
what is extracellular fluid (ECF)?
fluid surrounding the exterior of a cell
87
what are the subcategories of extracellular fluid?
* interstitial fluid
| * plasma
88
what is cytoplasm?
the compartment within a cell
89
what is cytosol?
ICF
90
what are the components of a cell membrane?
* phospholipids
* proteins
* carbohydrates
* cholesterol
91
how many layers of phospholipids are in a cell membrane?
bilayer (2)
92
what are micelles?
droplets of phospholipids with a single layer arrangement (important for lipid digestion
93
what is a liposome?
a bilayer arrangement of phospholipids with an aqueous core
94
what is an integral protein?
AKA transmembrane protein, has contact with ICF and ECF and travels all the way through a cell membrane
95
what is a peripheral protein?
a protein located only on the outside or inside of a cell
96
where are carbohydrates located on a plasma membrane?
only on the external side of the cell membrane (the extra cellular side)
97
what part of plasma membranes are carbohydrates anchored to?
Proteins and phospholipid heads
98
what is a glycoprotein?
a protein on a cell membrane with sugar (carbohydrates) attached to it
99
what is a glycolipid?
a phospholipid with sugar (carbohydrate) attached to it
100
what is the function of carbohydrates (sugars) on cell membranes?
cell recognition
101
where can cholesterol come from?
ingested through diet and the cells can manufacture it
102
what is the building blocks of steroids?
cholesterol
103
where is cholesterol located within the cell membrane?
with the phospholipid tails, because cholesterol and the phospholipid tails are both non polar and hydrophobic
104
what are ribosomes composed of?
a large subunit and a small subunit
105
what is the function of ribosomes?
protein synthesis
106
what type of protein do free ribosomes synthesize?
proteins for use within the cell
107
what type of protein do fixed ribosomes produce?
protein to be used in the cell membrane, incorporated in lysosomes, or to be exported from the cell
108
what is the cristae in mitochondria arranged in folds for?
to increase surface area for more efficient ATP production
109
what are fixed ribosomes attached to in a cell?
rough endoplasmic reticulum
110
are ribosomes inclusions or organelles?
inclusions
111
what is the function of mitochondria?
to make ATP
112
what is the function of rough and smooth endoplasmic reticulum?
rough endoplasmic reticulum - synthesizes proteins for plasma membrane, lysosomes, and secretion
smooth endoplasmic reticulum - site of steroid, phospholipid, and fatty acid synthesis
113
what are the functions of the golgi apparatus?
* verifies protein structures sent to it are correct
* modifies the plasma membrane
* packages enzymes for lysosomes
* sorts and packages materials for destined for lysosomes, plasma membrane, and to be secreted from cell
114
what do lysosomes contain within them?
powerful enzymes that only function in the acidic ph found within the lysosome
115
what is the function of lysosomes?
digestion of particles that enter the cell. once digested they release any useful components into the cell for use
116
what type of reaction occurs within peroxisomes?
oxidation reactions
117
what is the function of peroxisomes and what is the byproduct produced?
to break down fatty acids. H2O2 (hydrogen peroxide) is a byproduct of this breakdown
118
what do peroxisomes do to remedy waste products of its reactions?
peroxisomes use the enzyme catalase to break H2O2 (hydrogen peroxide) down into H20 (water) and O2 (oxygen)
119
what is the membrane around the nucleus called?
nuclear membrane or nuclear envelope
120
what are nuclear pores and what is their function?
pores in the nuclear envelope that allow things to move into and out of the nucleus
121
how big are nuclear pores?
nuclear pore size is dynamic and varies according to the size of the matter passing through
122
what is a nucleolus and what is its function?
the darker part of the nucleus that produces ribosomal subunits
123
where do ribosomal subunits combine to form functional ribosomes?
in the cytoplasm
124
what is chromatin?
strands of DNA with organizational proteins. chromosomes are made up of condensed chromatin
125
what is the path of mRNA?
* made in the nucleus, made from a DNA template
* travels through nuclear pores
* attaches to either fixed or free ribosomes to make proteins
126
how are proteins transported from rough ER to Golgi apparatus and from Golgi apparatus to the plasma membrane?
* transport vesicles transport proteins from rough ER to golgi apparatus
* secretory vesicles transports protein from the golgi apparatus to the plasma membrane
127
what are gap junctions?
proteins with channels fused within the plasma membrane of 2 cells that allows cells to quickly communicate
128
what are tight junctions and where are they located
Tight junctions fuse cell membranes together and prevent movement of molecules passed/between cells. mostly found more on the apical side of cells
129
what are desmosomes and where are they located?
desmosomes are reinforced cell junctions that tightly bind cells together. they tend to be found in areas that experience alot of stretching. they are usually found more on the basal side between cells.
130
which cell junctions usually work together on the same cells?
tight junctions and desmosomes
131
transport across membranes can be divided into what 2 subcatagories?
passive transport and active transport
132
what type of energy is used in active transport?
ATP (cellular energy)
133
what type of energy does diffusion use?
diffusion uses kinetic energy of molecular movement
134
which direction do molecules diffuse?
from area of higher concentration to areas of lower concentration
135
diffusion continues until when?
until equilibrium is reached. molecular movement will continue however
136
under which condition does diffusion occur faster?
* along higher concentration gradients
* over shorter distances
* at higher temperatures
* smaller molecules are being diffused
137
what is the concentration gradient?
the difference in concentration
138
in what environments can diffusion take place?
in an open system or across a partition
139
what can make diffusion across a membrane faster?
* larger membrane surface area
* thinner membrane
* larger concentration gradient
* size of molecule and permeability of cell membrane
* lipid solubility
140
what are channel proteins?
transport proteins within a cell membrane that have a water filled channel passing through them
141
what are the two types of channel protein?
* open channels (no mechanism to close them hence no regulation on molecular movement)
* gated channels(open and close in response to signals to regulate molecular movement)
142
what are the different types of gated channel protein?
```
Chemically gated (responds to the correct molecule binding to it)
voltage-gated (responds to cellular voltage)
Mechanically gated (responds to pressure)
```
143
what are carrier proteins?
transporter proteins proteins that never form an open channel between the two side of a membrane. it will be open to one side until a molecule binds to the binding site inside. then it will be closed off to both sides, then open on the other side to allow molecule to pass
144
what are the different types of carrier proteins and what are their functions?
* uniport carrier - moves only one type of substrate (molecules)
* symport carrier (cotransporter) - moves two or more different types of substrates (molecules)
* antiport carrier - moves substrates (molecules) in opposite direction
145
what are molecules called if they are being transported by carrier proteins and why?
substrates because they are binding to a binding site of the protein
146
what is the transport protein property "specificity"?
transport proteins that move only one type of molecule or structurally related molecules
147
what is GLUT?
what does it transport?
where is it located?
a glucose transport protein
it transports glucose and other carbohydrates
found in cell membranes of cells throughout
148
what is the carrier transport protein property "competition"?
closely related substrates compete for binding sites
149
what does it mean when carrier proteins are saturated?
all carrier proteins are filled with substrates and transport rate is maximum
150
describe facilitated transport
facilitated transport follows the same rules as diffusion but it relies on transport proteins to move molecules across a membrane
151
what happens to glucose when it enters a cell?
when a glucose molecule enters a cell it is broken down using 1ATP
ATP transfers one of its phosphates to the glucose transforming the glucose molecule into G-6-P
from there it is either broken down using glycolysis for ATP production or converted into glycogen
152
how does a cell maintain glucoses concentration gradient so it can continue to move into the cell down its gradient?
glucose is converted into G-6-P (a different molecule) and glucose is able to continue to enter the cell down its concentration gradient
153
what is ATPase?
a carrier protein that is able to hydrolyze ATP and utilize the energy from it to transport molecules across a cell membrane
154
what does ATP stand for and what does it consist of?
Adenosine triphosphate
it consists of 3 phosphates, a pentose sugar (ribose), and a nitrogenous base
It is a nucleotide
155
what type of transport uses cellular energy to move molecules against their concentration gradients?
primary active transport
156
what type of carrier protein is a sodium/potassium pump?
an antiport carrier
157
where are sodium and potassium concentrations greatest (ICF or ECF)?
sodium is more concentrated in the ECF
| potassium is more concentrated in the ICF
158
how many sodium and potassium molecules are transported through a sodium potassium pump per cycle?
3 sodium molecules and 2 potassium molecules
159
out of sodium, potassium, calcium, and chloride, which have higher concentrations within a cell?
only potassium has a higher concentration within the cell
160
what is secondary active transport?
it works the same way facilitated transport does in that it is driven by concentration gradient. however the concentration gradient molecules travel down in secondary active transport is produced by primary active transport.
161
What does SGLT stand for and what is it?
Sodium-linked Glucose transporter
It is a carrier protein that relies sodium binding to its binding site to grant affinity to the glucose binding site. the affinity on the glucose binding site attracts and holds glucose molecules in place until sodium is released.
162
what is phagocytosis?
cell engulfs bacterium or large particles into large vesicles called phagosomes
163
what performs phagocytosis?
the white blood cells macrophages and neutrophils
164
describe the process of phagocytosis within a white blood cell
phagocyte engulfs foreign material
encases foreign matter into a phagosome (vesicle made of plasma membrane
phagosome fuses with lysosomes and powerful enzymes break down foreign matter
destroyed and digested particles are released into the cell
165
what is endocytosis?
the importing of large molecules that are already a part of the ECF into a cell through a vesicle
166
what are the 2 types of endocytosis?
| describe them
pinocytosis- intake of ECF (cell drinking)
receptor-mediated- targeted substrates bind to protein receptors which then triggers endocytosis of the substrate (molecule)
167
what is exocytosis?
the exporting of large lipophobic molecules
168
in osmosis, which direction does water move?
toward areas of higher solute concentration/lower water concentration
*like in the diffusion of solutes, water moves down its concentration gradient*
169
what is osmotic pressure?
the amount of pressure needed to prevent water from performing osmosis across a membrane
170
what is tonicity?
tonicity describes how the concentration of solution around a cell affects the cells volume
171
what is a solution that is isotonic to a cell in it?
| what happens to the cells volume in this solution?
ECF solute/water concentration is equal to ICF solute/water concentration
nothing, cell does not change volume
172
what is a solution that is hypertonic to a cell?
| what happens to the cells volume in this solution?
ECF solute concentration is greater than ICF solute concentration
water will travel out of the cell into the ECF and make the cell shrivel
173
what is a solution that is hypotonic to cell?
| what happens to a cells volume when in a hypotonic solution?
ECF solute concentration is less than ICF solute concentration.
water molecules will move into the cell and cause it to swell and possibly burst
174
what is a chemical reaction?
the transformation of substances by either forming or breaking covalent bonds
(storing and releasing covalent bond energy)
175
in biology, what are the reactants of a chemical reaction referred to as and why?
reactants are referred to as substrates because usually an enzyme is involved to help the reaction take place
176
what is activation energy?
the minimum energy required to start a chemical reaction
177
describe exergonic and endergonic reactions.
exergonic reactions release energy as a product
| endergonic reactions need energy for the reaction to take place. the energy is stored in the bonds of the products.
178
what is a coupling reaction?
a reaction where energy released in an exergonic reaction(reaction that releases energy to the environment) drives an endergonic reaction(reaction that requires outside energy to drive it)
A + B -------> C + D + ENERGY-------ENERGY + A + B -------> D + C
179
which bond stores the most energy in a molecule of ATP?
the bond between phosphates 2 and 3
180
what method is used to break the third phosphate off of ATP?
hydrolysis
181
what are examples of coupling reactions?
NAD+ and NADH
ADP and ATP
FAD+ and FADH2
182
describe which of NAD+ and NADH are high and low energy molecules
```
NAD+ = low energy
NADH = high energy
```
183
describe which of ADP and ATP are high energy and low energy
```
ADP = low energy
ATP = high energy
```
184
describe which of FAD+ and FADH2 are high energy and low energy
```
FAD+ = low energy
FADH2 = high energy
```
185
describe the endergonic and exergonic reactions out of the molecules
ADP - ATP
NAD+ - NADH
FAD+ = FADH2
ADP-->ATP = endergonic (energy stored)
ATP-->ADP = exergonic (energy released)
NAD+ --> NADH = endergonic (energy stored)
NADH --> NAD+ = exergonic (energy released)
FAD+ --> FADH2 = endergonic (energy stored)
FADH2 --> FAD+ = exergonic (energy released)
186
where does NAD+ and FAD+ get energy to transform into NADH and FADH2?
from high energy electrons (2H+)
187
what are the characteristics of enzymes?
* structure is unchanged in a reaction
* they are not consumed in a reaction
* they reduce activation energy of a reaction to increase reaction rate
* there are a limited amount of enzymes produced by a cell
188
what are the properties of enzymes?
* specificity (only specific substrates can bind to an enzyme)
* competition (substrates with similar structures compete for binding sites on enzymes)
* saturation (when there are more substrates than enzymes, the enzymes are considered to be saturated. enzymes are working at maximum reaction rate)
189
what are isozymes?
enzymes that catalyze the same reactions but in different locations and/or body tissues
190
when is an enzyme activated for use?
after the enzymes protein structure is complete
191
what is proteolytic activation of an enzyme?
the zymogen (unfinished enzyme) is built with peptide bonds across gaps in the structure. the peptide bonds are shed upon enzyme completion. at that point it is considered an active enzyme (enzyme that is complete and ready for use)
192
how are enzymes activated for use?
* proteolytic activation
| * addition of cofactors
193
what is a cofactor and how does it activate an enzyme?
a cofactor is a segment that contains the active sites and is built separate from the inactive protein enzyme. once ready for activation, the cofactor binds to the inactive protein enzyme and renders the enzyme active for use
194
what is the difference between inorganic cofactors and coenzymes?
only the material it is made of. inorganic cofactors are made of inorganic molecules and coenzymes are made of organic molecules
195
how are enzymes deactivated?
* inhibitors - inhibitors bind to active sites of enzymes an block substrates from binding. the smooth surface of inhibitors prevents binding of substrates
* denaturation - enzymes lose 3-D shape that makes them functional enzymes
196
which factors are associated with denaturation?
* PH
| * Temp
197
what temperatures and PH levels do enzymes function optimally in?
it varies. different enzymes function optimally in different temps and PH levels
198
what is Catabolism?
the breaking down of large particles (releases energy)
199
what is anabolism?
the synthesis of large molecules (utilizes/stores energy)
200
what are the steps of cellular respiration?
1) Glycolysis
2) Pyruvate metabolism
3) Citric acid cycle
4) electron transport system
201
what occurs in glycolysis and where does it occur?
* glucose is phosphorylated by 1 ATP and it transformed into Glucose-6-phosphate
* The structure of G-6-P is changed to form fructose-6-phosphate
* fructose-6-phosphate is further phosphorylated by 1 ATP and forms fructose 1 -6-bisphosphate
* finally the fructose 1 -6-bisphosphate is split to form 2 molecules of 3 carbon pyruvate
(glycolysis occurs in the cytoplasm)
202
from 1 glucose molecule, how many molecules of energy were spent and gained in glycolysis?
```
2 ATP spent
4 ATP gained
2 NADH gained
NET GAIN OF ENERGY MOLECULES:
2 ATP
2 NADH
```
203
how many 3 carbon pyruvate are produced at the end of glycolysis?
2 3-carbon pyruvate
204
does glycolysis require oxygen?
no
205
what is produced in glycolysis of 1 glucose molecule?
2 3-carbon pyruvate
2 ATP
2 NADH
2 H20
206
what happens to pyruvate under anaerobic conditions?
energy from 2NADH is used to convert 2pyruvate into lactic acid (Lactate)
207
how many ATP are gained in an entire anaerobic respiration cycle with 1 molecule of glucose?
2 ATP
208
what happens to pyruvate from 1 glucose molecule in aerobic conditions?
2pyruvate travels through the mitochondrial membranes and into the mitochondrial matrix where it is converted into 2Acetyl CoA. the conversion of 2 pyruvate into 2 Acetyl CoA produces 2 NADH and 2 CO2
209
what happens to the 2 Acetyl CoA molecules produced from a molecule of glucose in the citric acid cycle?
what is produced?
* the 2 Acetyl CoA molecules combine with 2 molecules of Oxaloacetate to form 2 molecules of Citrate. Citrate continues around the citric acid cycle until it becomes Oxaloacetate once again.
* the citric acid cycle produces 6 NADH, 2 FADH2, 2 ATP, and 4 CO2.
210
what is the function of the electron transport system and where does it take place?
the electron transport system converts NADH and FADH2 into ATP
this process occurs entirely in the mitochondrial matrix
211
what provides the energy for H+ protons to travel through transport proteins in the inner mitochondrial membrane against their concentration gradient?
the release of high energy electron bond energy from NADH and FADH2 molecules that travel through the transport proteins along the inner mitochondrial membrane
212
what happens to high energy electrons in the electron transport system after they have traveled through the transport proteins in the inner mitochondrial membrane?
H+ returns to the mitochondrial matric and binds with O2 molecules to form H20
213
what is the purpose of the high H+ concentration gradient between the mitochondrial intermembrane space and the inner membrane in electron transport system?
the high concentration gradient allows H+ to travel through ATP synthase using only kinetic energy of diffusion. the energy of their travel is used to convert ADP + P into ATP
214
how much ATP is produced in the electron transport system?
26-28 ATP
215
how do NADH molecules made outside of the mitochondria participate in the electron transport system?
each NADH molecule is converted into an FADH2 molecule and then transported into the mitochondrial matrix for processing
216
how much ATP does 1 molecule of NADH produce in the electron transport system?
how much ATP does 1 molecule of FADH2 produce in the electron transport system?
1 NADH = 2.5 ATP
| 1 FADH2 = 1.5 ATP
217
in fed state metabolism what happens to glucose and what is this process called?
Glycogenesis:
1) glucose enters the cell
2) glucose is converted to Glucose-6-phosphate at the cost of 1ATP
3) before g-6-p is able to enter into glycolysis, glucose-6-phosphate rearranges itself to form glucose-1-phosphate
4) finally g-1-p is attached to glycogen for later use
218
how is triglyceride formed from glucose molecules and what is this process called?
Lipogenesis:
1) a 3 carbon molecule of glycerol leaves glycolysis before it has had a chance to change into pyruvate
2) 2 carbon acetyl units exit pyruvate metabolism before it has had a chance to move into the citric acid cycle and bond with one another to form fatty acids
3) fatty acid chains are attached to each of the 3 carbons found in glycerol until a molecule of triglyceride has been formed.
219
what happens to glycogen in fasted state metabolism and what is this process called?
Glycogenolysis: this is the opposite process as glycogenesis
(NET GLUCOSE PRODUCTION)
1) glycogen is broken down into glucose-1-phosphate molecules
2) the phosphate bond is rearranged to form glucose-6-phosphate
3) the phosphate bond is broken releasing energy that is captured by ADP (producing one molecule of ATP)
4) glucose molecules are left over
220
which metabolism state does protein metabolism occur in?
fasted-state metabolism
221
describe the steps and processes of protein metabolism
1) hydrolysis: peptidase and H20 is used to break peptide bonds holding amino acid structures together.
2) deanimation: NAD + H2O is used to break the bond holding the amino group from the rest of the structure. this produces 1 NADH molecule
3) Urea formation: NH3 is formed from the separation of the amino group. H+ ions are added to NH3 to form NH4 (ammonium) and finally urea.
222
where does organic acids from protein metabolism end up?
they end up in either glycolysis or the citric acid cycle
223
what happens to triglycerides in fasted state metabolism and what is this process called?
Lipolysis:
1) lipases digest triglyceride into glycerol and 3 fatty acids
2) glycerol becomes a glycolysis substrate
3) fatty acid chains move into the mitochondrial matrix where beta-oxidation chops the 2 carbon acetyl units off of the fatty acid chains
4) acetyl units become acetyl CoA and can then be used in the citric acid cycle
224
what organelle takes part in beta-oxidation of fatty acid in the mitochondrial matrix?
peroxisomes
225
what is gluconeogensis?
the generation of glucose molecules from non carbohydrate substrates
226
when does gluconeogensis occur?
during times of extended fasting, starvation, low carb diets, and exercise
227
describe gluconeogensis
process
1) lactate is converted back into pyruvate which then undergoes gluconeogensis which is the opposite of glycolysis
2) organic acid from amino acids(from protein hydrolysis) and/or glycerol (from lipolysis) are used in gluconeogensis to produce molecules of glucose
3) this costs 2 ATP and 2 NADH to perform
228
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**DIGESTIVE SYSTEM**
what is digestion?
what is absorption?
what is motility?
what is secretion?
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digestion - chemical and mechanical breakdown of food into absorbable units
absorption - movement of material from GI lumen to ECF
motility - movement of material through GI tract as a result of muscle contraction
secretion - movement of material from cells to ECF or GI lumen
229
what enzymes are responsible for breaking down carbohydrates in the small intestines?
amylase breaks polysaccharides down into disaccharides
disaccharides are broken down into monosaccharides using molecule specific enzymes (brush boarder enzymes)
* * maltase breaks maltose down into 2 glucose molecules
* *sucrase breaks sucrose down into 1 glucose and 1 fructose
* *lactase breaks lactose down into 1 glucose and 1 galactose
230
what are microvilli in the small intestines known as?
the brush boarder
231
how is glucose and galactose absorbed into capillaries from the small intestine?
glucose and galactose enter intestinal mucosa cells via sodium symporter (SGLT) and exit through GLUT2 transport proteins
232
how does fructose get absorbed into capillaries from the small intestine?
fructose enters intestinal mucosa cells through GLUT5 transport proteins and exit via GLUT2 transport proteins
233
where are carbohydrates sent to after absorption and why?
the liver so they can be converted into glycogen
234
what breaks peptide bonds during protein digestion in the small intestine?
peptidase which is a brush boarder enzyme is used to break peptide bonds between amino acids
235
how are individual amino acids absorbed into the capillaries from the small intestine?
individual amino acids travel into intestinal mucosa cells via sodium linked symporter and exit via sodium linked antiporter
236
how are di and tripeptides absorbed into capillaries from the small intestine?
di and tripeptides are transported into the cell with hydrogen ions via symporter
hydrogen that comes into the cell with the di or tripeptides are removed through a sodium/hydrogen antiporter
on the basilar side of the cell they are exchanged with hydrogen ions via antiport transport protein
237
how are peptides larger than 3 absorbed into capillaries from the small intestine?
they enter the intestinal mucosa via endocytosis and exit via exocytosis
238
of protein, carbohydrates, and fat, which takes the longest to digest?
fat
239
how is fat digested?
1) bile coats lipid droplets
2) pancreatic lipase and colipase break fats into monoglycerides and fatty acids which are stored in micelles
3) monoglycerides and fatty acids diffuse into intestinal mucosa and then diffuse out of the basil side
4) monoglycerides and fatty acids enter the lymphatic system and travel through as lacteal
5) it travels to the vena cava and enters blood stream
240
why does the pancreas secrete bicarbonate into the duodenum?
to buffer stomach acids present in chyme
241
describe enzymes that are secreted by the pancreas
inactive enzymes called zymogens are secreted and activated in a cascade.
when activated they help digest proteins, fats, and carbohydrates
242
what does the large intestine absorb?
H2O
vitamins
electrolytes
243
what is feces stored and what signals its excretion?
in the rectum, rectal stretch signals the CNS
