Chapter 2 Flashcards
1
Q
Matter
A
all living and nonliving things are composed of matter, which is anything that occupies space and has mass
2
Q
Mass
A
is the amount of matter in an object
3
Q
weight
A
is the gravitational force acting on an object of a given mass
4
Q
atom
A
is the smallest particle of an element that has the chemical characteristics of that element
5
Q
neutron
A
no electrical charge
6
Q
proton
A
one positive charge
7
Q
electron
A
one negative charge
8
Q
Nucleus of an atom
A
- the centre of the atom
- protons and neutrons are found in the centre of the atom
- electrons are found in an electron cloud that orbits around the nucleus
9
Q
chemical bond
A
association between two atoms formed when the outermost electrons are transferred or shared between atoms
10
Q
What is an atom called that has gained or lost an electron?
A
ion
11
Q
A molecule is formed when two or more ______ chemically combine.
A
atoms
12
Q
A molecule may be described as ______.
A
two or more atoms that are chemically bonded to one another
13
Q
Frequently, a phosphate group will react with adenosine diphosphate to form adenosine triphosphate. This is an example of a(n) ______ reaction..
A
Synthesis
14
Q
A weak attraction between a slightly positive region of one molecule and a slightly negative region of another molecule would be a(n) ______ bond.
A
Hydrogen
15
Q
True or false: When ATP is broken down, the energy that is transferred from this reaction can be used to synthesize molecules, perform work or produce heat.
A
TRUE
16
Q
By definition, a(n) ______ releases hydrogen ions when it is placed in a water solution.
A
acid
17
Q
In a synthesis reaction, the ______ is larger than the ______.
A
product, reactants
18
Q
Substances that resist changes in pH are known as
A
buffers
19
Q
How are salts formed?
A
By the reaction of an acid and a base
20
Q
atomic number
A
the number of protons and electrons (cause the amount of each is equal) in each atom
For example: hydrogen atoms have one proton (and 1 electron), and carbon atoms have 6 protons (and 6 electrons)
21
Q
Mass in atoms
A
protons and neutrons have about the same mass and they are responsible for most of the mass of atoms
- electrons have very little mass
The mass number of an element is determined by adding the number of protons and neutrons in each atoms - for example, carbon has 6 protons and 6 neutrons its mass number is 12 (6+6=12)
22
Q
isotopes
A
are two or more forms of the same element that have the same number of protons and electrons, but have a different number of neutrons
- most familiar isotopes are those that are radioactive, for example, PET scan uses radioactive isotopes to examine blood flow to certain organs or to detect cancer
23
Q
Chemical bonds
A
association between two atoms formed when the outermost electrons are transferred or shared between atoms
24
Q
valence shell
A
the outermost shell of an atom (think that there 2 electrons in the first ring, then the second ring can hold up to 8 electrons)
- the number of electrons in the valence shell determines an atom’s chemical behaviour
- if an atoms valence shell is not at its maximum (8 electrons), it will form bonds with other atoms to achieve a full valence shell, called an octet.
25
atoms achieve an octet in one of two ways
1. by transferring electrons between atoms (ionic bond)
2. by sharing electrons between atoms (covalent bond)
- whether an electron is transferred or shared between two atoms is determined by the relative electronegativities of two atoms (electronegativity is the ability of the atoms nucleus to pull electrons towards it)
- atoms w strong electronegativity have 6-7 electrons on valence shell while weak ones have 1-2 electrons on valence shell
26
ion
atom or group of atoms carrying an electrical charge because of a loss or gain of one or more electrons
- a sodium atom Na can lose an electron to become a positively charged sodium ion Na+, and a chlorine atom Cl can accept an electron to become a negatively charged chloride ion Cl-
- after this transfer, both chlorine and sodium have full valence shells
27
ionic bond
because oppositely charged ions are attracted to each other, negatively charged ions and positively charged ions tend to remain close together
- thus an ionic bond forms when electrons are transferred between atoms, creating oppositely charged ions
Example: Na+ and Cl- are held together by ionic bonding to form an array of ions called sodium chloride NaCl or table salt
28
Covalent bond
forms when atoms share one or more pairs of electrons
- sharing rather than transferring occurs because the atoms have similar electronegativities
- therefore the resulting combination of atoms are called molecules
29
The formation of a covalent bond between two hydrogen atoms to form a hydrogen molecule
1. initially the two atoms do no interact, because they are too far apart. Each hydrogen atom has 1 electron.
2. as the atoms get closer together, each hydrogen atom's positively charged nucleus begins to attract the electron of the other hydrogen atom
3. a non polar covalent bond forms when the electrons are shared equally between the nuclei, because the electrons have the same attraction to each nucleus. The two hydrogen atoms are held together by a non polar covalent bond and now form a non polar molecule
30
non polar molecule
a molecule formed by non polar covalent bonds where there is equal sharing of electrons between atoms of the molecule. A non polar molecule carries a neutral charge
31
polar covalent bond
chemical bond in which electrons are shared unequally between two atoms
- occurs when the two atoms involved in a covalent bond have different electronegativites thus forming a polar covalent bond
- polar covalent bonds can result in polar molecules, which are electrically asymmetric
32
compound
is a substance resulting from the chemical combination of two or more different types of atoms
- water is a compound AND a molecule (not all molecules are compounds)
- sodium chloride NaCl is a compound but not a molecule (it is an ion b/c of its ionic bonding and transfer or electrons)
33
intermolecular forces
are the weak charge attractions that exist between separate molecules, or between ions and molecules
- different from other chemical bonds because there is no exchange of electrons
- intermolecular forces are simply due to attractions between oppositely charged regions of molecules and include hydrogen bonds and the property of dissociation
34
hydrogen bonds
bonds between molecules
- the attraction of oppositely charged ends of one polar molecule to another polar molecule holds molecules or parts of molecules together
35
dissociation
When ionic compounds dissolve in water, their ions dissociate or separate, from each other because the positively charged ions are attracted to the negative ends of the water molecules, and the negatively charged ions are attracted to the positive ends of the water molecules
- the separation of positive and negative ions when they dissolve in water and are surrounded by water molecules
36
electrolyte
Positive and negative ions that conduct electricity in solution
- for example, a ECG is a recording of electrical currents produced by the heart, these currents can be detected by electrodes on the surface of the body because the ions in the body fluids conduct electrical currents
37
molecules in water
when molecules dissolve in water, the molecules usually remain intact even though they are surrounded by water molecules
38
chemical reaction, reactants, and products
A chemical reaction is the formation or breaking of chemical bonds between atoms, ion, molecules, or compounds.
The substances that enter into a chemical reactions are called reactants
The substances that result from the chemical reaction are called products
39
Synthesis reaction
When two or more reactants combine to form a larger, more complex product.
A + B -> AB
Example: ADP + Pi (phosphate group) -> ATP
- all synthesis reactions that occur in the body are collectively referred to as anabolism
- growth, maintenance, and repair of the body cannot take place without anabolism reactions
- synthesis reactions in which water is also a product are called dehydration reactions
40
decomposition reaction
reactants are broken down into smaller, less complex products
- reverse of a synthesis reaction
AB -> A + B
Example: ATP -> ADP + Pi
- the decomposition reactions that occur in the body are collectively called catabolism
- an example of decomposition reaction is the breakdown of food into individuals nutrients, which uses water in the process
- reactions that use water in this way are called hydrolysis reactions
- they include the digestion of food molecules in the intestine and within cells, the breakdown of lipid stores, and the breakdown of foreign matter and microorganisms in certain blood cells that protect the body
41
anabolic and catabolic reactions in the body
are defined as metabolism
42
Exchange reactions
is a combination of decomposition reaction and a synthesis reaction
AB + CD -> AC + BD
An example of an exchange reaction is the reaction of hydrochloric acid (Hal) with sodium hydroxide (NaOH) to form table salt (NaCl) and water (H2O)
HCl + NaOH -> NaCl + H2O
43
Reversible reactions
the reaction can run in the opposite direction, so that the products are converted back to the original reactants
- when the rate of product formation is equal to the rate of reactant formation, the reaction is said to be at equilibrium
- this kind of reaction is formed by have two arrows on top of each --> <--
44
Energy
is the capacity to do work
- work is the movement of matter
- energy is the ability to put matter into motion
45
potential energy
stored energy
46
kinetic energy
is energy caused by the movement of an object and is the form of energy that actually does work
47
potential and kinetic energy exist in many different forms
mechanical energy, chemical energy, heat energy, electrical energy, and electromagnetic (radiant) energy
48
mechanical energy
resulting from the position or movements of objects
- moving a limb, breathing, or circulating blood is mechanical energy
49
chemical energy
is a form of potential energy stored within the chemical bonds of a substance
ADP (less potential energy in reactants) + Pi + energy (from food molecules) --> ATP (more potential energy in products)
ATP (more potential energy in products) --> ADP (less potential energy in reactants) + Pi + energy (used by cells)
50
Catalyst
increases the rate of a chemical reaction, without being permanently changed or depleted
51
enzymes
is a protein catalyst that increases the rate at which chemical reactions proceeds, without the enzyme being permanently changed
- typically end in a 'ase'
- increase the rate of chemical reactions by lowering the activation energy, which is the energy necessary to start a chemical reaction
52
acid and bases
the body has many molecules and compounds called acids and bases that can alter body functions
53
acid
is a proton donor
- b/c hydrogen atom without its electron is a proton, any substance that releases hydrogen ions (H+) in water is an acid
54
base
is a proton acceptor
- example: sodium hydroxide (NaOH) forms sodium ions (Na+) and hydroxide ions (OH-). it is a base because the OH- is a proton acceptor that binds with a H+ to form water
55
pH scale
is a means of referring to the H+ concentration in a solution
- concentration of H+ determines the pH value
- scale ranges from 0 to 14
- neutral solution has an equal number of H+ and OH- and has a pH of 7
- acidic solution has a greater concentration of H+ than of OH- and the pH is LESS than 7
- a basic solution (or alkaline) has fewer H+ than OH- and the pH is GREATER than 7
- a solution w a pH of 6 has 100 times more H+ than a solution with a pH of 8
56
acidosis
the normal pH range for human blood is 7.35 to 7.45, if the blood drop below 7.35, the condition is acidosis
- the nervous system is depressed, and the individual becomes disoriented and possible comatose
- can result in death
57
Alkalosis
- if blood pH rises above 7.45, alkalosis results
- the nervous system becomes overexcitable and the individual can be extremely nervous or have convulsions
- can result in death
58
salt
salt is a compound consisting of a positive ion other than H+ and a negative ion other than OH-
- salts are formed by the reaction of an acid and a base
HCl (acid) + NaOH (base) -> NaCl (salt) + H2O (water)
59
Buffer
is a chemical that resists changes in pH when either an acid or base is added to a solution containing the buffer
- buffers reduce large changes in pH by binding and releasing H+
- when an acid is added to a buffer solution, the buffer binds to the H+, preventing these ions from causing a decrease in the pH of the solution
60
inorganic chemistry
deals with substances that do NOT contain carbon
- lacks carbon-hydrogen bonds
- CO2 and carbon monoxide (CO) are important inorganic substances that contain carbon, but LACK carbon-hydrogen bonds
61
organic chemistry
is the study of carbon-containing substances
62
Oxygen (O2)
is a small, non polar, inorganic molecule consisting of 2 oxygen atoms bound together by a double covalent bond
- about 21% of the gas in the atmosphere is O2
63
Carbon Dioxide (CO2)
consists of one carbon atom bound to two oxygen atoms
- each oxygen atom is bound to the carbon atom by a double covalent bond
- produced when food molecules, such as glucose, are metabolised within the cells of the body
- once it is produced, it is eliminated from the cell as a metabolic by-product, transferred to the lungs by the blood, and exhaled during respiration
- if CO2 accumulates within the cell it becomes toxic
64
Water
- polar
- water molecule is formed when an atom of oxygen forms polar covalent bonds with two atoms of hydrogen
- water stabilises body temperature
- water protects the body
- water is required for many chemical reactions
65
The purposes of cells utilising organic molecules
1. as energy molecules for synthesis of ATP
2. as structural components of the cell
3. as regulatory molecules
66
what's the backbone of many large molecules?
carbon atoms bound together by covalent bonds are the backbones
67
two mechanisms that allow for the formation of a wide variety of molecules
1. variation in the length of the carbon chains
2. the combination of the atoms involved
68
four major groups of organic molecules essential living organisms are
1. carbohydrates
2. lipids
3. proteins
4. nucleic acids
69
Carbohydrates
Organic molecules composed of carbon, hydrogen, and oxygen atoms
3 major roles in the body:
1. they are parts of other organic molecules
2. they are broken down to provide energy
3. when undigested, they provide bulk (fibre) in feces
- for each carbon atom there are two hydrogen atoms and one oxygen atom
- simplest carbohydrates are monosaccharides, or simple sugars, it is a building block for more complex carbohydrates
- glucose (blood sugar) and fructose (fruit sugar) are important monosaccharide energy sources for many of the body cells - cells preferentially use glucose to synthesise ATP
- disaccharides are formed when two monosaccharides are joined by a covalent bond
- for example: glucose and fructose combine to form the disaccharide sucrose (table sugar)
- polysaccharides consist of long chains of monosaccharides
70
The 3 important polysaccharides
1. glycogen
- main storage form of glucose in humans
- glucose is quickly broken down by cells to make ATP
- glycogen serves as a ready supply of more glucose for ATP production
2. starch
3. cellulose
- starch and cellulose are found in plants
- both are composed of long chains of glucose
- starch stores energy for plants in the same way as glucose stores energy
- when humans ingest starch our cells can break it down and sue the glucose to make ATP
- humans cannot digest cellulose and it is eliminated in the feces
- the presence of cellulose (fibre) in our diet is important for regularity of bowel movements and has been reported to help reduce cholesterol and control blood sugar levels
71
lipids
insoluble in water
- less polar
important functions:
1. provide protection and insulation
2. help regulate many physiological processes
3. form membranes
4. major energy storage molecules, which can be broken down and used as an energy source
major classes of lipids:
1. fats - mostly triglycerides
2. phospholipids
3. eicosanoids
4. steroids
- building blocks of fast are glycerol and fatty acids (glycerol is at the top head, and the fatty acid is the legs - I think)
- triglycerides have 3 fatty acids bound to a glycerol molecule
- fatty acid is saturated if it contains only single covalent bonds between the carbon atoms (means that each carbon is full w hydrogen)
- carbon chain is unsaturated if it has one or more double covalent bonds (double covalent bonds introduce kinks into the carbon chain, which tends to keep them liquid at room temperature)
- trans fats are unsaturated fats that have been chemically altered by the addition of H atoms (have a longer shelf life) but greater risk for cardiovascular disease
- phospholipid have a polar phosphate head and nonpolar 2 fatty acid chains. The head is hydrophilic and the non polar end is hydrophobic - important structural components of cell membranes
- eicosanoids are a group of important chemicals derived from fatty acids - made in most cells and are important regulatory molecules (they respond tissue injuries I think)
- example of eicosanoids is prostaglandins which regulate the secretion of some hormones, blood clotting, some reproductive functions, and more
- anti-inflammatory medications are effected in result from their ability to inhibit prostaglandin synthesis
- steroids are lipids that have 4 ringlike structures, cholesterol is important one b/c other steroid molecules are synthesised from it
- steroids derived from cholesterol include bile salts (lipid digestion), estrogen, progesterone, and testosterone
- cholesterol is important component of cell membrane
- cholesterol is needed for normal functioning but too much increases risk of cardiovascular disease
72
proteins
important functions:
1. regulation of body processes
2. acting as a transportation system
3. providing protection
4. helping muscles contract
5. providing structure and energy
- protein molecules are bound together by covalent bonds
- most proteins also contain sulfur and some contain small amounts of phosphorus
- building blocks of proteins are amino acids (contain -NH2)
- protein consists of many amino acids bound by covalent bonds called peptide bonds
- 20 different amino acids
- hydrogen bonds between amino acids in the chain cause the chain to fold or coil into a specific three-dimensional shape
- if it loses its shape (if hydrogen bonds break) the protein becomes nonfunctional and this change is called denaturation and can be caused by high temperatures or changes in pH
- proteins can be enzymes
73
DNA - deoxyribonucleic acid
genetic material of cells
- DNA contains genes which determines the structure of proteins
- DNA is a double helix
- the sides of the ladder are formed by covalent bonds between the monosaccharides and phosphate groups of adjacent nucleotides
- the rungs of the ladder are formed by nitrogenous bases of the nucleotides of one side connected to the bases of the other side by hydrogen bonds
- each nucleotide of DNA contains one of the nitrogenous bases: adenine, thymine, cytosine, or guanine
- A-T, C-G, and hydrogen bonds between them
- DNA stores information used to determine the structures and functions of cells
74
RNA - Ribonucleic acid
structurally related to DNA and important in protein synthesis
- single strand similar to DNA but single
- 4 different nucleotides make up RNA molecule, all the same BUT thymine is replaced with uracil, uracil can only bind to adenine
75
nucleotides
basic building blocks of DNA and RNA
composed of:
- monosaccharide
- nitrogenous base
- phosphate group
76
ATP - adenosine triphosphate
most important molecule for storing and providing energy in all living organisms
ATP consists of:
- adenosine (a monosaccharide with adenine)
- 3 phosphate groups
- the 3 negatively charged phosphate groups make ATP a very unstable molecules
- breaking the phosphate bonds releases a large of amount of energy
- removal of the third phosphate group generates adenosine diphosphate (ADP) which has 2 phosphate groups and much less potential energy than ATP
