GEN BIO: PROTEINS and NUCLEIC ACIDS Flashcards
1
Q
From the Greek word proteios, meaning “first place,” suggests the importance of this class of macromolecules
A
Proteins
2
Q
6 BIOLOGICAL FUNCTIONS OF PROTEINS
A
- Enzymes – Ribonuclease
- Regulatory proteins – Insulin
- Transport proteins – Hemoglobin
- Structural proteins – Collagen
- Contractile proteins – Actin, Myosin
- Exotic proteins – Antifreeze proteins in fish
3
Q
OTHER TYPES OF PROTEINS
A
- DEFENSIVE PROTEINS
- SIGNAL PROTEINS
- RECEPTOR PROTEINS
- STORAGE PROTEINS
4
Q
Type of Protein. Antibodies of the immune system
A
- DEFENSIVE PROTEINS
5
Q
Type of Protein. many of the hormones and other messengers that help coordinate body activities by communicating between cells
A
- SIGNAL PROTEINS
6
Q
Type of Protein. may be built into cell membranes and transmit signals into cells
A
- RECEPTOR PROTEINS
7
Q
Type of Protein. such as ovalbumin, the protein of egg white, which serves as a source of amino acids for developing embryos
A
- STORAGE PROTEINS
8
Q
Probably the most important role for proteins is as __________
A
Enzymes
9
Q
biological catalysts that speed and regulate virtually all chemical reactions in cells
A
Enzymes
10
Q
found in hair and the fibers that make up connective tissues such as tendons and ligaments.
A
STRUCTURAL PROTEINS
11
Q
Muscles contain _______ and __________ proteins.
A
contractile; regulatory
12
Q
Contractile Proteins (2)
A
Myosin and Actin; functions in shortening the muscle fibers
13
Q
Contractile Proteins (2)
A
Myosin and Actin; function in shortening the muscle fibers
14
Q
Regulatory Proteins (2)
A
Tropomyosin and Troponin
- starts and stops shortening of muscle cell
- troponin moves tropomyosin off the actin active sites
15
Q
Muscle contraction is activated by the release of calcium into sarcoplasm and its binding to troponin. With what type of protein?
A
Regulatory PRotein=Tropomyosin and Troponin
16
Q
Regulatory Protein formed in pancreatic tissue that helps to regulate blood sugar level
A
Insulin
17
Q
Other proteins called _________ regulate biosynthesis of enzymes
A
Repressors
18
Q
Proteins that protect against disease
A
Defensive Proteins
19
Q
A ________ is a protein molecule usually found embedded within the plasma membrane surface of a cell that receives chemical signals from outside the cell and when such chemical signals bind to a receptor, they cause some form of cellular/tissue response.
A
Receptor
20
Q
Functions in storage of amino acids
A
Storage Proteins
21
Q
Protein in Milk
A
Casein
22
Q
Exotic Proteins
A
- Monelin
- Antifreeze
- Resillin
23
Q
Protein of an African plant has an intensely sweet taste and used as non toxic food sweetener for human use
A
Monelin
24
Q
Protein present in wing hinges of some insects with elastic properties
A
Resillin
25
PROTEINS ARE MADE FROM AMINO ACIDS LINKED BY ________ BONDS
PEPTIDE
26
Protein diversity is based on differing arrangements of a common set of just _______ amino acids.
20
27
Amino acids all have an ______ and a _______ group
amino group; carboxyl
28
These functional groups (amino and carboxyl) are covalently bonded to a central carbon atom, called the ________
alpha carbon.
29
Also bonded to the alpha carbon is a ________ and a chemical group symbolized by the ____.
hydrogen atom; letter R
30
the simplest amino acid; the R group is just a hydrogen atom
Glycine
31
structure of the ________ determines the specific properties of each of the 20 amino acids that are found in proteins.
R group
32
Aspartate doesn't have _____ compared to aspartic
H atom
33
________ residues function in many enzyme-catalyzed reactions as proton donors and/or acceptors
Histidine
34
Amino acids with ___________ help proteins dissolve in the aqueous solutions inside cells
polar and charged R groups
35
Cells join amino acids together in a dehydration reaction that links the carboxyl group of one amino acid in the amino group of the next acid as a water molecule is removed. The resulting covalent linkage is called a _____________
peptide bond.
36
The product of the reaction from two amino acids is a ________
dipeptide.
37
Chain of amino acids
Polypeptide
38
The beginning amino group in a dipeptide
Terminal Amino Group (N-Terminal)
39
The end group in a Dipeptide
Terminal Carboxyl Group (C-Terminal)
40
Most polypeptides are at least how many amino acids in length?
100
41
T or F. Each polypeptide has a unique sequence of amino acids.
T
42
one or more polypeptide chains precisely coiled, twisted, and folded into a unique three-dimensional shape.
Proteins
43
A protein’s _______ determines its function
specific shape
44
a process where polypeptide chains unravel, losing their specific shape and as a result, their function
Denaturation
45
Causes of Denaturation
Change in salt concentration, pH, excessive heat
46
4 levels of structure for protein shape
Primary
Secondary
Tertiary
Quaternary
47
a protein’s unique sequence of amino acids
Primary Structure
48
T or F. Even a slight change in a protein’s primary structure may affect its overall shape and its ability to function
T
49
parts of the polypeptide coil or fold into local patterns called _______
Secondary Structure
50
In Secondary Structure, coiling results in a ________ and certain kinds of folding leads to a________
alpha helix; beta pleated sheet
51
T or F. Beta Pleated sheets are found in fibrous and globular protein
T
52
What stabilizes the B-pleated sheet?
hydrogen bonds between peptide bonds
53
Both alpha helix and beta pleated sheets are maintained by regularly spaced __________between the hydrogens of the –N-H groups and the oxygens of the –C=O groups of neighboring peptide bonds along the polypeptide chain
hydrogen bonds
54
Many fibrous proteins, such as the structural protein of hair, have the ________ structure over most of their length
alpha-helix
55
_________ make up the core of many globular proteins
Pleated sheets
56
refers to the overall three-dimensional shape of a polypeptide
Tertiary Structure
57
Most _________can be roughly described as either globular or fibrous. Generally, results from interactions among the R groups of the amino acids making up the polypeptide
tertiary structures
58
- Many proteins consist of two or more polypeptide chains or subunits. Such proteins have a ________, resulting from the association of the subunits.
quaternary structure
59
infectious misshapen proteins that are associated with serious degenerative brain diseases such as mad cow disease.
* Prions
60
diseases such as Alzheimer’s and Parkinson’s involve an accumulation of _______
misfolded proteins.
61
The amino acid sequence of a polypeptide is programmed by a discrete unit of inheritance known as
gene.
62
Genes consist of __________, one of the two types of polymers known as nucleic acids.
DNA (deoxyribonucleic acid)
63
A gene does not put its genetic DNA information to work directly. It works through an intermediary –the second type of nucleic acid known as _________.
ribonucleic acid (RNA)
64
The monomers that make up nucleic acid
nucleotides.
65
nucleotide has three parts
-A five-carbon sugar (DNA has deoxyribose, whereas RNA has ribose)
-Linked to one side of the sugar is a phosphate group
-Linked to the sugar’s other side is a nitrogenous base
66
DNA nucleotide vs. RNA nucleotide
DNA - has Thymine
- doesn't have O in carbon 2
RNA - has Uracuk
- has O in carbon 2
67
* Like polysaccharides and polypeptides, a nucleic acid polymer-a ___________-forms from its monomers by __________ reactions.
polynucleotide; dehydration
68
T or F. The phosphate group of one nucleotide bonds to the phosphate of the next monomer. result is a repeating sugar-phosphate backbone in the polymer.
F. The phosphate group of one nucleotide bonds to the sugar of the next monomer.
69
DNA is a double helix, in which __________ wrap around each other.
two polynucleotides
70
T or F. nitrogenous bases protrude from the two sugar-phosphate backbones into the center of the helix in DNA
T
71
A certain purine can only pair with a certain pyrimidine. A pairs with T, and C pairs with G. This is known a base complementary rule or _______.
Chargaff’s Rule
72
T or F. Two DNA chains are held in a double helix by hydrogen bonds between their paired bases.
T
73
Every base pair in the double helix is separated from the next base pair by _____nm.
0.34 nm
74
The two strands of the double helix run in opposite directions (__________ orientation)
antiparallel
75
mainly involved in the process of protein synthesis under the direction of DNA.
RNA
76
Usually single-stranded and is made of ribonucleotides
RNA
77
Ribonucleotide in the RNA chain contains_________(the pentose sugar), one of the four nitrogenous bases (A, U, G, and C) and the phosphate group.
ribose
78
4 major types of RNA:
1. messenger RNA (mRNA)
2. ribosomal RNA (rRNA)
3. transfer RNA (tRNA)
4. microRNA (miRNA)
79
carries the message from DNA, which controls all of the cellular activities
messenger RNA
80
major constituent of ribosomes on which the mRNA binds
ribosomal RNA
81
ensures the proper alignment of the mRNA and the ribosomes
ribosomal RNA
82
has enzymatic activity and catalyzes the formation of the peptide bonds between two aligned amino acids
ribosomal RNA
83
Polymers of amino acids arranged in a linear sequence
Proteins
84
Enzymes that break down their substrates
Catabolic Enzymes
85
Enzymes that build more complex molecules from their substrates are called?
Anabolic Enzymes
86
Enzymes that affect the rate of reaction are called?
Catalytic Enzymes
87
In every reaction, an enzyme will bind with a substrate in an area on the enzyme's surface called the _______, forming a substrate-enzyme complex.
Active Site
88
An enzyme which hydrolyzes its substrate amylose, a component of starch
Salivary Amylase
89
Each enzyme is specific for the substrate (a reactant that binds to an enzyme) it acts on, such that their active sites have very precise shapes, that only, one substrate can fit in each site and is chemically attracted
to it. This is known as
Enzyme-Substrate Specificity
90
rates of enzyme reactions are also affected by different factors such as
temperature, pH, and amount of substrate.
91
T or F. chemical reactions increase as temperature increases
T. chemical reactions increase as temperature increases because the reacting molecules move faster and collide more often.
92
However, as the temperature continues to increase beyond the optimum temperature, ___________
occurs: chemical bonds of the enzymes break causing alteration in the shape of the active site until it is no longer complementary to the substrate molecule.
enzyme denaturation
93
T or F. s. Most enzymes in the human body have optimum temperature at 37.0 'C. But some enzymes in organisms that live in extreme conditions, like those
in bacteria which thrive in hot springs or hydrothermal vents, can have extreme optimum temperatures of more than 65"C.
T
94
T or F. pH, which indicates the acidity/basicity of a solution, actually measures the concentration of hydrogen ions (H+). The lower the pH, the higher the concentration of H+ ions there is.
T.
94
T or F. pH, which indicates the acidity/basicity of a solution, actually measures the concentration of hydrogen ions (H+). The lower the pH, the higher the concentration of H+ ions there is.
T.
95
Most enzymes found in the human body have optimum
pH between pH ____
6-8
96
T or F. enzyme activity decreases as substrate concentration increases
F. Increases
97
Active sites of enzymes is said to be saturated with the substrate and thus called the _____
saturation point
98
monomers that make up proteins
Amino Acids
99
Structure of amino acid
- central carbon atom (alpha carbon)
- amino group
- carboxyl group
- hydrogen atom
- R-group
100
______ is an exception to the standard structure of amino acid, since its amino group is not separate from the side chain
Proline
101
Amino acids are represented by a _________
single upper case letter or a three-letter abbreviation
102
___________ and ________ in the polypeptide chain ultimately determine the protein's shape, size, and function.
amino acid sequence and the number of amino acids
103
products formed by such linkages (peptide bonds) are called ______
peptides; polypeptides as more amino acids join
104
After protein synthesis (translation), most proteins are modified. These are known as ______
post-translational modifications
105
The unique sequence for every protein is ultimately determined by the _____ encoding the protein.
gene
106
The local folding of the polypeptide in some regions
Secondary Structure
107
The a-helix and b-pleated sheet are secondary structures of proteins that form because of ________ between carbonyl and amino groups in the
peptide backbone.
hydrogen bonding
108
Every helical turn in an alpha helix has ______ amino acid residues.
3.6
109
T or F. In the b-pleated sheets, the pleated segments align parallel or antiparallel to each other, and hydrogen bonds form between the partially positive nitrogen
atom in the amino group and the partially negative oxygen atom in the carbonyl group of the peptide backbone.
T
110
The a-helix and B-pleated sheet structures are found in most ____ and _____, and they play an important structural role.
globular and fibrous proteins
111
When protein folding takes place, the hydrophobic R groups of nonpolar amino acids lay in the interior of the protein, whereas the hydrophilic R groups lay on the outside. The former types of interactions are also known as __________
hydrophobic interactions
112
In nature, some proteins are formed from several polypeptides (each polypeptide is called a subunit), and the interaction of these subunits forms
the ________
quaternary structure.
113
T or F. Not all proteins are denatured at high temperatures;
T. Not all proteins are denatured at high temperatures; for instance, bacteria that survive in hot springs have proteins that function at temperatures close to boiling. The stomach is also very acidic, has a low pH, and denatures proteins as part of the digestion process; however, the digestive enzymes of the stomach retain their activity under these conditions
114
Protein folding is critical to its function. It was originally thought that the proteins themselves were responsible for the folding process. Only recently was it found that often they receive assistance in the folding process from protein helpers known as_________that associate with the target protein during the folding process. They act by preventing aggregation of polypeptides that make up the complete protein structure and they disassociate from the protein once the target protein is folded.
chaperones (or.chaperonins)
115
_______ are the most important macromolecules for the continuity of life. They carry the genetic blueprint of a cell and carry instructions for the functioning of the cell.
Nucleic acids
116
T or F. In prokaryotes, the DNA is not enclosed in a membranous envelope, unlike eukaryotes.
T
117
In eukaryotic cells but not in prokaryotes, DNA forms a complex with histone proteins to form _______, the substance of eukaryotic chromosomes.
chromatin
118
The DNA molecules never leave the nucleus, but, use an intermediary to communicate with the rest of the cell instead. This intermediary is the ______
messenger RNA (mRNA).
119
Other types of RNA-like rRNA IRNA,
and microRNA-are involved in ______ and _____
protein synthesis and its regulation.
120
The nitrogenous bases, important components of nucleotides, are organic molecules and named because they contain carbon and nitrogen. They are bases because they contain an amino group that has the potential of _________; thus, decreasing the hydrogen ion concentration in its environment and making it more basic.
binding an extra hydrogen
121
Adenine and guanine are classified as______. The primary structure of a _______ is two carbon-nitrogen rings represented by adenine and guanine.
purines
122
Cytosine, thymine, and uracil (RNA) on the other hand, are classified as _______ which have a single carbon-nitrogen ring as their primary structure
pyrimidines
123
T or F. Purines have a double-ring structure, and
pyrimidines have a single ring.
T.
124
The phosphate residue is attached to the hydroxyl group of the 5'carbon of one sugar and the hydroxyl group of the 3'carbon of the sugar of the next nucleotide, which forms a 5'-3' ________
phosphodiester linkage.
125
The two strands of the helix run in opposite directions,
meaning that the 5' carbon end of one strand will face the 3' carbon end of its matching strand. (This is referred to as ____________and is important to DNA replication and in many nucleic acid interactions.)
antiparallel orientation
126
Only certain types of base pairing are allowed. For example, a certain purine can only pair with a certain pyrimidine. This means A can pair with T, and G can pair with C. This is known as the base complementary rule or __________
Chargaffs Rule.
127
RNA, is mainly involved in the process of protein
synthesis under the direction of _____
DNA
128
The mRNA is read in sets of three bases known as _______. Each ____ codes for a single amino acid. In this way, the mRNA is read and the protein
product is made. I
codons
129
________ is one of the smallest of the four types of RNA, usually 70-90 nucleotides long. It carries the correct amino acid to the site of protein synthesis.
Transfer RNA (tRNA)
130
_________ are the smallest RNA molecules, and their role involves the regulation of gene expression by interfering with the expression of certain mRNA messages.
MicroRNAs (miRNA)
131
DNA dictates the structure of mRNA in a process known as _______n, and
RNA dictates the structure of a protein in a process called_______.
transcriptio; translation
