Section 2: Chemistry of Life Flashcards
1
Q
What are carbohydrates?
A
- serve as fuel and building material
-Include sugars and their polymers
-Monosaccharides/disaccharides and polysaccharides
2
Q
What are examples of carbohydrates?
A
Monosaccharides: glucose, galactose, fructose
Disaccharides: sucrose, lactose, maltose
Polysaccharides: starch, cellulose (most abundant compound on earth)
3
Q
Draw a carbohydrate
A
(This can be glucose w ring structure)
4
Q
What are defining characteristics of Lipids?
A
-Hydrophobic
-Makes membranes, energy, insulation, messengers
-fatty acids, triglycerides, phospholipids
-There key feature is that they are amphipathic: membrane-forming
DO NOT form polymers
5
Q
Draw cholesterol
A
6
Q
What are proteins?
A
polymers of amino acids
7
Q
What are nucleic acids?
A
-Informational polymers made of nucleotides
-DNA makes RNA
-RNA makes protein
-Nucleotides have 3 parts, base, sugar, phosphate
8
Q
Draw a DNA chain -
A
Base, Sugar, Phosphate
9
Q
What is the base pair rule?
A
For DNA: A & T
C & G
For RNA: A & U
C & G
10
Q
What is DNA?
A
a double helix - found by Rosalind Franklin
11
Q
What are the four classes for biological macromolecules?
A
- Carbohydrates
- Lipids
- Nucleic acids
- Proteins
12
Q
What are the different types of carbohydrates?
A
The simplest are monosaccharides (simple sugars) this includes glucose and fructose
-Hydroxyl groups make them water-soluble (dissolve in water)
-Usually occur as polymers: polysaccharides (starch, cellulose)
- A lot of complexity in their chemistry and functions (chitin: in cell wall of fungi) sulfate and dermatan sulfate
13
Q
What are hydrocarbons?
A
organic molecules with hydrogen and carbon
- many organic molecules, such as fats have hydrocarbon components
-they can undergo reactions that release a large amount of energy
14
Q
What do nucleic acids do?
A
- Store, transmit and help express hereditary information
- Nucleic acids are made of monomers called nucleotides
- A gene consists of DNA
15
Q
What is ATP and what is it used for?
A
it is an important source of energy for cellular processes (it really is energy)
- it is an organic phosphate (adenosine triphosphate)
- consists of an organic molecule called adenosine attached to a string of three phosphate groups
16
Q
What is COPD also known as Chronic Obstructive Pulmonary Disease
A
The enlargement of the alveoli (tiny air sacs in the lungs) accompanied by the destruction of the cell walls ALSO known as emphysema
17
Q
What are the functions of proteins?
A
- Cells building blocks
-They account for more than 50% of the dry mass of most cells - Some proteins speed up chemical reactions
- Other functions are: defense, storage, transport, cellular communication, movement, and structural support
18
Q
What is an enzymatic protein?
A
Function: selective acceleration of chemical reactions
Example: digestive enzymes catalyze the hydrolysis of bonds in food molecules
19
Q
What is a defense protein?
A
Function: protein against disease
Example: Antibodies inactivate and help destroy viruses and bacteria
20
Q
What is a storage protein?
A
Function: storage of amino acids
Examples: casein the protein of milk is the major source of amino acids for baby mammals
21
Q
What are transport proteins?
A
Function: transport of substances
Examples: Hemoglobin, the iron-containing protein of vertebrate blood, transports oxygen from the lungs to other parts of the body
22
Q
What are hormonal proteins?
A
Function: Coordination of an organism’s activities
Example: Insulin, a hormone caused by the pancreas, causes other tissues to take up glucose, regulating blood sugar concentration
23
Q
What are Receptor proteins?
A
Function: response of cell to chemical stimuli
Example: receptors built into the membrane of a nerve cell detect signaling molecules released by other nerve cells
24
Q
What are Contractile and motor proteins?
A
Function: movement
Examples: motor proteins are responsible for the undulations (moving slowly up and down) of cilia and flagella. Actin and myosin are responsible for the contraction of muscles
25
what are structural proteins?
Function: support
Examples: Keratin is the protein of hair, horns, feathers and other skin appendages. Collagen and elastin proteins provide fibrous framework in animal connective tissue
26
What are enzymes?
They are proteins that act as catalysts to speed up chemical reactions
27
What are proteins constructed of?
the same set of 20 amino acids (this means that they are more easily identified)
28
What are polypeptides?
unbranched polymers built from amino acids
29
What is a protein?
Biologically functional molecule that consists of one or more polypeptides
30
What are amino acids?
organic molecules with amino and carboxyl groups
31
Why do amino acids differ in their properties?
Because they have differing side-chains, called R groups
32
Draw the base amino acid:
Found in red notebook
33
What are amino acids monomers?
amino acids are organic molecules with amino and carboxyl groups
- amino acids differ in their properties due to their differing side chains called R groups
34
What are polypeptides?
Amino acids are linked by covalent bonds called peptide bonds (so amino acids linked together)
- a peptide bond is a polymer of an amino acid
- Polypeptides range in length, from a few to mora than 1,000 monomers (monomer is a bond between two identical molecules)
- Each polypeptide has a unique linear sequence of amino acids, w a carboxyl and and an amino end
35
Draw an amino acid monomer:
(in red notebook for reference)
36
Draw a polypeptide:
37
What are the four levels of protein structure?
- Primary structure of a protein is its unique sequence of amino acids
- Secondary structure is found in most proteins, consists of coils and folds in the polypeptide chain
- Tertiary structure is determined by interactions among various side-chains
- Quaternary structure results when a protein consists of multiple polypeptide chains
38
What does the secondary protein structure look like?
it is an alpha helix that is spiraled or it is a beta strand that is pleated
39
What does the tertiary structure look like?
It has the a-helix, b-pleated sheet and transthyretin polypeptide
40
What does the quaternary protein structure look like?
Single polypeptide unit and transthyretin protein
41
Why are there coils in the secondary structure of protein?
There are coils and folds because of the hydrogen bonds, repeating in the polypeptide backbone
42
How does sickle cell disease affect the protein structure of blood cells?
Sickle cell disease affects the primary structure which affects the proteins ability to function,
- Sickle cell disease is an inherited blood disorder that results from a single amino acid substitution in the protein hemoglobin
- abnormal hemoglobin molecules cause the red blood cells to aggregate into chains and to deform into a sickle shape
43
What determines protein structure?
chemical and physical conditions can affect structure
- Alterations to pH, salt concentrations, temperature, or other environmental factors can cause proteins to unravel
44
What is denaturation?
when a proteins native structure is lost
45
What do Parkinson's and mad cow disease have in common?
They are both associated with misfolded proteins
46
What is matter in the universe made up of?
everything is made up of atoms
47
What are the parts of an atom and there charge:
Atoms have protons (positive charge, neutrons (neutral charge), electrons (negative charge)
48
What are protons and neutrons measured in?
They are measured in daltons
49
Where are valence electrons placed?
They are on the outermost shell
50
What happens when atoms have incomplete valence shells?
They can share or transfer valence electrons with certain atoms
51
What is a compound?
a substance containing two or more elements of a fixed ratio
52
What is a covalent bond?
Sharing of valence electrons by two atoms
53
What is electronegativity?
The more electronegative an atom is the more it pulls shared electrons to it
54
What is a nonpolar covalent bond?
atoms share the electron equally
55
What is a polar covalent bond?
one atom is more electronegative and the atoms do not share the electron equally
56
What is key to a molecules function?
shape and size determine a molecules function - shape also determines how biological molecules recognize and respond to each other
57
What do chemical reactions do to chemical bonds?
They make and break chemical bonds
58
What is thermodynamics the study of?
the study of energy transformations, in an open system, energy and matter can be transferred between the system and its surroundings
59
what happens in a closed system in thermodynamics?
In a closed system energy will exchange with its surroundings but not matter
60
What is the first law of thermodynamics?
the energy of the universe is constant. Energy can be transferred or transformed but it cannot be created or destroyed
61
What is the second law of thermodynamics?
During every transfer or transformation, some energy is unusable and is often lost as heat.
- Every energy transfer or transformation increases entropy of the universe
- Entropy is the measure of molecular disorder or randomness
62
What is free energy?
a measure of a systems instability, its tendency to change to a more stable state
63
what happens during a spontaneous change?
free energy decreases and the stability of a system increases
64
What are catabolic pathways?
they release energy by breaking down complex molecules into simpler compounds - such as cellular respiration (breakdown of glucose in the presence of oxygen)
65
What are anabolic pathways?
they consume energy to build complex molecules from simpler ones (synthesis of proteins from amino acids)
66
When can free energy work?
When temperatures and pressures are uniform, as in a living cell
67
What is an exergonic reaction?
proceeds with a net release of free energy and is spontaneous
68
What is an endergonic reaction?
absorbs free energy from its surroundings and is non-spontaneous
69
What is a catalyst?
a chemical agent that speeds up a reaction without being consumed by the reaction
70
What kind of reaction does ATP generate?
ATP is an endergonic reaction
71
Why is ATP endergonic?
it is a renewable resource that is regenerated by the addition of phosphate group to (ADP)
72
What is ATP composed of?
ribose (a sugar), adenine (nitrogenous base), three phosphate groups
73
How does ATP power cellular work?
it couples exergonic reactions with endergonic reactions
74
How is the cellular work powered by ATP?
the three types of cellular work are powered by the hydrolysis of ATP (breaking of compound due to water)
75
What does ATP hydrolysis lead to?
change in protein shape and binding ability
76
What does an enzyme act on?
this is called a substrate
77
What forms an enzyme-substrate complex?
When an enzyme binds to its substrate
78
Where does a substrate bind on an enzyme?
This is called an active site
79
How can you speed up the reaction if the enzyme is saturated?
reaction rate can only be sped up by adding more enzyme
80
What are cofactors?
they are nonprotein enzyme helpers, they can be inorganic (such as metal in ionic form) or organic
81
What is an organic cofactor called?
this is called a coenzyme and includes vitamins, which are vital for our bodies to function in small quantities. Cofactors will sit in the active site and help the substrate bind correctly
82
What is an inactive enzyme called?
an inactive enzyme is called apoenzyme
83
What is a competitive inhibitor?
they bind to the active site of an enzyme, and compete with the substrate
84
What is a non-competitive inhibitor?
it bind to another part of the enzyme, causing the enzyme to change shape and making the active site less effective
85
What are examples of inhibitors?
toxins, poisons, pesticides and antibiotics
86
What is allosteric regulation?
it either inhibits or stimulates enzyme activity, this happens when a regulatory molecule binds to a protein at one site and affects the proteins function at another site
87
What is feedback inhibition?
when the end product of a metabolic pathway shuts down the pathway, prevents the cell from wasting
88
What is cooperativity in enzymes?
a form of allosteric regulation that can amplify enzyme activity - cooperativity is allosteric
89
What is selective permeability?
it means to allow some substances to cross more easily than others
90
What are fats constructed from?
2 smaller molecules: glycerol and fatty acids
91
What are saturated fatty acids?
they have the maximum number of hydrogen atoms possible and no double bonds
- They are solid at room temperature (think of butter)
- Animal fats
92
What are unsaturated fatty acids?
They have one or more double bonds
- Liquid at room temperature (think oil, like olive oil)
- Found in fish and plants
93
What is cholesterol?
- it is a type of steroid and characterized by a carbon skeleton and four fused rings
94
What does cholesterol do in the membrane?
At warm temperatures cholesterol restrains the movement of phospholipids and at cool temperatures it maintains fluidity by preventing tight packing
95
What are peripheral proteins?
They are proteins bound to the surface if the membrane
96
What are integral proteins?
They penetrate the hydrophobic core, integral proteins that span the membrane are called transmembrane proteins
97
What determines most of a membranes functions?
proteins determine most of a membranes function
98
What do aquaporins do?
They facilitate the passage of water molecules
99
What is passive transport?
Diffusion is an example of passive transport and it is the tendency for molecules to spread out evenly into the available space
NO energy is expended by the cell in passive transport
100
What is osmosis?
diffusion of water across a selectively permeable membrane, water diffuses across the membrane from the region of lower solute to higher solute (to even things out/create homeostasis)
101
What is tonicity?
the ability of a surrounding solution to cause a cell to gain or loose water, tonicity depends on its concentration of solutes that cannot cross the membrane
102
What does it mean to be isotonic?
The solute concentration is the same inside and outside the cell (nothing moving back and forth to create osmosis)
103
What does it mean to be hypertonic?
the solute concentration is greater outside of the cell than inside (loss of water, cell shrivels)
104
What does it mean to be hypotonic?
the solute concentration inside the cell is more so it gains water (cell wall burst, water floods in)
105
What is facilitated diffusion?
transport proteins speed the passive movements of molecules across the plasma membrane
106
What is a gated channel in facilitated diffusion?
ion channels open or close in response to a stimulus and these are considered gated
107
Is facilitated diffusion still considered passive transport?
yes, because it moves the solute down the concentration gradient (no energy is required)
108
What is active transport?
this requires energy, usually in the form of ATP to move substances against their concentration gradients, proteins involved in active transport are carrier proteins
109
What is the sodium potassium pump?
This is a transport protein that is energized by transfer of a phosphate group from the hydrolysis of ATP
110
What is membrane potential?
it is the voltage across the membrane, the cytoplasmic side of the membrane in negative in charge relative to the extracellular side
111
What is a electrogenic pump?
a transport protein that generates voltage across a membrane (the major example of this is the sodium potassium pump). For plants, fungi and bacteria the main electrogenic pump is a proton pump
112
What is Cotransport?
when active transport of a solute indirectly drives the transport of another substance
113
What is exocytosis?
In exocytosis transport vesicles migrate to the membrane, fuse with it, and release their contents outside the cell, many secretory cells use exocytosis to export their products (especially cells of the digestive tract)
114
What is endocytosis?
When the cell takes in macromolecules by forming vesicles from the plasma membrane (reversal of exocytosis)
115
What is digestion?
the process of breaking down food into molecules small enough to absorb (starts in the mouth)
116
Why does the small intestine have a huge surface area?
This is because of villi and microvilli
117
Where is excess energy first stored?
in the liver and muscle cells in a polymer called glycogen (branched chain form of glucose)
118
How are carbohydrates broken down?
They are broken down into glucose by various enzymes, some glucose is used immediately but the majority enters the blood stream triggering insulin release and the uptake of glucose into cells
119
What is Acetyl-CoA?
it come from metabolized carbohydrates, fats, and proteins, it is and important part of the process which creates the energy molecule called ATP
120
What is Ghrelin?
it is a hormone secreted by the stomach wall, that triggers feelings of hunger before meals
121
What is insulin?
it is a hormone from the pancreas secreted in the small intestine after meals
122
What is leptin?
produced by adipose (fat) tissue, suppresses appetite and plays a role in regulating body fat levels
123
Where are insulin and glucagon both produced?
They are produced in the pancreas
124
What makes glucagon and insulin?
Alpha cells make glucagon and beta cells make insulin
125
What triggers the synthesis of glycogen?
higher insulin levels triggers the synthesis of glycogen
126
What is glucose useful for?
it is useful for short bursts of energy without the use of oxygen (but the breakdown of amino acids and fats requires oxygen)
127
What is glycolysis? and what type of process is it?
Glycolysis is the breakdown of glucose by enzymes, releasing energy and pyruvic acid, this is an exergonic process
128
What is glucogenesis and what type of process is it?
Glycogenesis is the synthesis of glucose and is an endergonic process
129
What happens to triglycerides in the lumen of the gut?
triglycerides aggregate (formed by combining several elements) into fat globules as a consequence of aqueous environments
130
What do bile salts do?
break down fat globules so that triglycerides can be accessed
131
What do epithelial cells do?
they absorb fatty acids and monoglycerides then recombine them back into triglycerides
132
What happens when the body needs energy?
adipose cells mobilize the triglycerides into free fatty acids and glycerol, which are then released into the blood
133
What kind of process is fatty acid breakdown?
this is an oxidative process that has 4 steps
134
What is Malonyl-CoA?
it is a key inhibitor of fatty acid oxidation and controls the switch between fatty acid synthesis and oxidation
