Chapter 2 Flashcards
1
Q
Define element.
A
Element is the simplest form of matter to have unique chemical properties
2
Q
Define Atomic number (for an element).
A
It is the Number of protons in the nucleus
3
Q
How many elements have biological roles?
A
24
4
Q
How many elements make up 98.5% of the body?
A
6
5
Q
What are the 6 elements make up the 98.5% of the body?
A
Oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus
6
Q
Define trace elements.
A
They are present in minute amounts, but play vital roles
7
Q
What are minerals?
A
They are Inorganic elements extracted from soil by plants and
passed up food chain to humans
8
Q
Minerals constitute what % of the body weight?
A
Constitute about 4% of body weight.
1. Ca and P make up about 3%
2. Remaining 1% is mainly Cl, Mg, K, Na, and S
9
Q
Define electrolytes.
A
Electrolytes are mineral salts needed for nerve and muscle function
10
Q
Minerals are essential for:
A
- Important for body structure (Ca crystals in teeth, bones, etc.)
- Important for enzyme function
11
Q
Who proposed planetary model of atomic structure in 1913?
A
Neils Bohr
12
Q
Where can the nucleus be found in an atom?
A
center of atom
13
Q
Where can the electron be found in an atom?
A
In concentric clouds surrounding nucleus
14
Q
What is a proton’s charge and atomic mass unit (amu)?
A
single (+) charge; mass = 1 atomic mass unit (amu)
15
Q
What is a neutron’s charge and atomic mass unit?
A
no charge; mass = 1 amu
16
Q
Where can the proton and neutron be found in an atom?
A
Nucleus
17
Q
Define Atomic mass.
A
The mass of an atom. It is approximately equal to total AMU of protons and neutrons
18
Q
What is the charge and atomic mass unit of an electron.
A
single (–) charge, very low mass
19
Q
Why is an atom considered electrically neutral?
A
Because number of electrons equals number of protons
20
Q
Valence electrons orbit in what shell and determine what?
A
Valence electrons orbit in the outermost shell and determine
chemical bonding properties of an atom
21
Q
Describe Isotope.
A
Isotopes are varieties of an element that differ only in the
number of neutrons
22
Q
Extra neutrons increase:
A
atomic weight
23
Q
Isotopes of an element are chemically similar because:
A
they have the same number of valence electrons
24
Q
Atomic weight (relative atomic mass) of an element accounts
for the fact that an element is a:
A
mixture of isotopes
25
What are considered Radioisotopes?
Unstable isotopes that decay and give off radiation
26
Intense radiation can be what and can cause what.
Intense radiation can be ionizing (ejects electrons, destroys
molecules, creates free radicals) and can cause genetic
mutations and cancer. Examples: UV radiation, X-rays, alpha particles, beta particles, gamma rays
27
Every element has at least one radioisotope. True/False
True
28
Sievert (Sv) is the unit of :
radiation dosage
29
Who coined the term radiativity and died of radiation poisoning?
Madame Curie
30
What is an ion?
Ions are charged particle (atom or molecule) with unequal number of protons and electrons
31
Define Ionization.
Involves Transfer of electrons from one atom to another
32
Define Anion?
It is a Particle that has a net negative charge (due to gain of
electrons)
33
Define Cation?
It is a Particle that has a net positive charge (due to loss of
electrons)
34
Ions with opposite charges are attracted to each other. True/False
True
35
What are Electrolytes?
They are substances that ionize in water and form solutions capable of conducting electric current
36
Why are electrolyte important?
1.Chemical reactivity
2. Osmotic effects
3. Electrical excitability of nerve and muscle
37
Define free radicals?
They are short-lived particles with an unusual number of electrons
38
How are free radicals produced?
They are produced by normal metabolic reactions, radiation, certain chemicals
39
How are free radicals dangerous to humans?
Trigger reactions that destroy molecules, and can cause cancer, death of heart tissue, and aging
40
Describe antioxidants.
They are chemicals that neutralize free radicals
41
Describe Superoxide dismutase (SOD).
Superoxide dismutase (SOD) is an antioxidant enzyme in the body
42
What are some antioxidants obtained through diet?
Selenium, vitamin E, vitamin C, and carotenoids are antioxidants obtained through the diet
43
Define Molecules
Particle composed of two or more atoms united by a chemical bond
44
Define Compound
Molecule composed of two or more different elements
45
Define Isomers
Molecules with identical molecular formulae but different arrangements of atoms
46
Define Molecular formula
Identifies constituent elements and how many atoms of each are present
47
Define Structural formula
Identifies location of each atom
48
Define Molecular Weight (MW)
The molecular weight (MW) of a compound is the sum of the atomic weights of its atoms.
49
List the 4 kinds of chemical bonds found in living organisms.
a. van der Walls forces
b. Ionic Bond
c. Covalent Bond
d. Hydrogen Bond
50
Describe Chemical Bond.
Hold atoms together within a molecule, or attract one molecule to another
51
Describe Ionic Bond.
a. Attraction of a cation to an anion.
b. Easily broken by water
52
Describe Covalent Bond.
Atoms share one or more pairs of electrons.
a.Single covalent bond: nuclei share 1 pair of electrons
b. Double covalent bond: nuclei share 2 pairs of electrons
53
Describe Nonpolar covalent bond.
Electrons shared equally
54
Describe Polar covalent bond.
Electrons shared unequally (spend
more time near oxygen)
55
Describe Hydrogen Bond.
Weak attraction between a slightly positive hydrogen atom in one molecule and a slightly negative oxygen or nitrogen atom in another atom
56
Water molecules are attracted to each other by:
Hydrogen bonds.
57
Large molecules (DNA and proteins) are shaped in part by the formation of which bonds within them.
Hydrogen Bonds.
58
Describe Van der Waals forces
Weak, brief attractions between neutral atoms
59
Describe Mixtures
Consist of substances that are physically blended but not chemically combined
60
Body fluids are complex mixtures of chemicals dissolved/suspended in water. True/False
True
61
List the properties of water that accounts for its ability to support life.
* Solvency
* Cohesion
* Adhesion
* Chemical reactivity
* Thermal stability
62
Describe the Solvency property of water.
* Ability to dissolve other chemicals
* Water is called the universal solvent
* Metabolic reactions depend on solvency of water
63
What are hydrophilic substances?
* Substances that dissolve in water
* Hydrophilic molecules are polarized or charged (e.g., sugar)
64
What are hydrophobic substances?
* Substances that do not dissolve in water
* Hydrophobic molecules are nonpolar or neutral (e.g., fats)
65
For water to dissolve salt, what occurs?
* Water forms hydration spheres around each ion and the salt dissolves
* Water’s negative pole faces Na+, its positive pole faces Cl–
66
Describe the adhesive property of water.
Tendency of one substance to cling to another
67
Describe the cohesive property of water.
* Tendency of like molecules to cling to each other
* Water is very cohesive due to its hydrogen bonds
68
Surface film on surface of water is due to molecules being held together by:
surface tension
69
What are some ways by which water participate in chemical reactivity?
* Water ionizes into H+ and OH–
* Water ionizes many other chemicals (acids and salts)
* Water is involved in hydrolysis and dehydration synthesis reactions
70
what is the base unit of heat?
Calorie (cal)
71
Define heat capacity.
Amount of heat needed to raise the temperature of 1 g of a substance by 1 °C
72
What is a protein?
A protein is a polymer made up of amino acids.
73
What is the basic structure of an amino acid?
An amino acid has a central carbon with three attachments: an amino group (-NH2), a carboxyl group (–COOH), and a radical group (R group).
74
How are amino acids differentiated from one another?
Amino acids are identical except for their radical (R) group, which determines the unique properties of each amino acid.
75
What is a peptide?
A peptide is composed of two or more amino acids joined by peptide bonds.
76
What is a peptide bond and how is it formed?
A peptide bond joins the amino group of one amino acid to the carboxyl group of another, and it is formed by dehydration synthesis.
77
How are peptides classified based on the number of amino acids?
* Dipeptides: 2 amino acids
* Tripeptides: 3 amino acids
* Oligopeptides: 3-15 amino acids
* Polypeptides: 15-50 amino acids
* Proteins: More than 50 amino acids
78
What is protein conformation?
Protein conformation is the unique, three-dimensional shape of a protein that is crucial to its function.
79
Which of the following processes can cause a protein to change conformation?
A) Muscle contraction
B) Enzyme catalysis
C) Membrane channel opening
D) All of the above
D) All of the above
80
What is denaturation?
A) A reversible change in protein shape
B) A loss of protein function due to extreme conformational change
C) The addition of amino acids to a protein
D) A type of peptide bond
B) A loss of protein function due to extreme conformational change
81
What are two causes of protein denaturation?
Extreme heat or pH changes can cause permanent denaturation, destroying protein function.
82
What determines the primary structure of a protein?
The primary structure is the sequence of amino acids within a protein molecule, and it is encoded by genes.
83
What type of bonds hold together the secondary structure of a protein?
Hydrogen bonds between the C = O group and N – H group hold together the secondary structure.
84
What are the two most common secondary protein structures?
α helix and the β pleated sheet.
85
What interactions shape the tertiary structure of a protein?
Hydrophobic–hydrophilic interactions and van der Waals forces cause further bending and folding into globular or fibrous shapes.
86
In which structure level does the association of two or more polypeptide chains occur?
A) Primary structure
B) Secondary structure
C) Tertiary structure
D) Quaternary structure
D) Quaternary structure
87
Which of the following proteins has a quaternary structure?
A) Alpha helix
B) Beta-pleated sheet
C) Hemoglobin
D) Collagen
C) Hemoglobin
88
What is the difference between globular and fibrous proteins?
Globular proteins have compact tertiary structures, suited for cell membrane roles or free movement in body fluids, while fibrous proteins are slender filaments ideal for muscle contraction and strengthening skin and hair.
89
What is a conjugated protein?
A conjugated protein contains a non-amino acid component, called a prosthetic group, covalently bound to it. Example: hemoglobin contains a heme moiety.
90
Which of the following is a tough structural protein found in hair, nails, and the skin surface?
A) Collagen
B) Keratin
C) Hemoglobin
D) Elastin
B) Keratin
91
What is collagen and where is it found?
Collagen is a structural protein found in the deeper layers of skin, bones, cartilage, and teeth.
92
What are signaling molecules that bind reversibly to receptor proteins called?
A) Ligands
B) Neurotransmitters
C) Antibodies
D) Enzymes
A) Ligands
93
What roles do glycoproteins and antibodies play in the body?
Glycoproteins are important for immune recognition, while antibodies are proteins that provide protection by recognizing harmful agents.
94
How do channel proteins and carrier proteins differ in membrane transport?
Channel proteins allow hydrophilic substances to diffuse across membranes, while carrier proteins help solutes cross via active or passive transport.
95
What is the function of motor proteins?
Motor proteins are molecules that enable movement by repeatedly changing shape.
96
How do proteins aid in cell adhesion?
Proteins bind cells together, facilitating cell adhesion.
97
What is the primary function of enzymes?
Enzymes are proteins that function as biological catalysts, lowering the activation energy required for reactions and allowing them to occur rapidly at body temperature.
98
What is a substrate in enzyme action?
A) The enzyme’s cofactor
B) The substance an enzyme acts upon
C) The byproduct of the reaction
D) The active site of the enzyme
B) The substance an enzyme acts upon
99
How are enzymes typically named?
Enzymes are named for their substrate, with the suffix "-ase" (e.g., amylase acts on amylose, lactase acts on lactose).
100
What model is used to describe enzyme–substrate specificity?
A) Induced fit
B) Lock and key
C) Substrate-product
D) Enzyme-reaction
B) Lock and key
101
What are cofactors and why are they important for enzyme function?
Cofactors are non-protein helper molecules required by many enzymes to function. They can be inorganic ions or organic molecules (coenzymes).
102
What is a coenzyme, and can you give an example?
Coenzymes are organic cofactors, often derived from vitamins. Example: NAD+, derived from niacin, plays a key role in metabolism and ATP production.
103
How does temperature and pH affect enzyme activity?
Temperature and pH can change enzyme shape and function. Each enzyme has an optimal pH (e.g., salivary amylase at pH 7.0, pepsin at pH 2.0) and typically works best near body temperature (37°C).
104
Are enzymes consumed in the reactions they catalyze?
No, enzymes are not consumed; they are reusable and can catalyze millions of reactions per minute.
105
What are nucleic acids, and what are their types?
Nucleic acids are polymers of nucleotides. The two main types are DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).
106
Which of the following is true about DNA?
A) It is a single strand
B) It contains instructions for synthesizing proteins
C) It is involved in protein assembly
D) It is made up of 70 to 10,000 nucleotides
B) It contains instructions for synthesizing proteins
107
What are the three types of RNA, and what is their function?
The three types of RNA are messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA). RNA carries out genetic instructions for synthesizing proteins and assembles amino acids in the correct order to produce proteins.
108
How does DNA indirectly control protein synthesis?
DNA is transcribed into RNA in the nucleus, and RNA is translated into proteins in the cytoplasm, guiding the process of protein assembly.
109
What process occurs first in the flow of genetic information?
A) Protein synthesis
B) DNA replication
C) RNA transcription
D) RNA translation
C) RNA transcription
110
What is the relationship between genes and DNA?
Genes are units of inheritance that consist of DNA, which programs the sequence of amino acids in a polypeptide.
111
How does RNA differ from DNA in terms of structure?
RNA is typically single-stranded and contains ribose sugar, while DNA is double-stranded and contains deoxyribose sugar.
112
What is the primary function of DNA?
DNA's primary function is to store genetic information and provide instructions for the synthesis of proteins.
113
How is genetic information passed from parents to offspring?
DNA is inherited from an organism’s parents and carries the genetic information necessary for development, functioning, and reproduction.
114
What happens during RNA translation?
During RNA translation, the mRNA sequence is used to assemble amino acids in the correct order to form a protein in the cytoplasm.
115
Which type of RNA is responsible for carrying the genetic instructions from DNA to the ribosome?
A) rRNA
B) tRNA
C) mRNA
D) cRNA
C) mRNA
116
What is the difference between transcription and translation?
Transcription is the process where DNA is converted into RNA in the nucleus, while translation is the process where RNA is used to assemble proteins in the cytoplasm.
