Chapter 2 Flashcards
The Chemistry of Life (98 cards)
1
Q
Matter
A
Makes up every object. Every object consists of one or more elements that organize into atoms and molecules
2
Q
Bulk element
A
Element that an organism requires in large amounts
-Carbon, hydrogen, oxygen, and nitrogen (makes up 96% of human body)
3
Q
Trace elements
A
Elements that an organism requires in small amounts
-ex. iron and zinc
4
Q
Radioactive isotope
A
Atom that emits particles or rays and its nucleus disintegrates
5
Q
Living things are mostly composed of 6 elements
A
-hydrogen
-oxygen
-carbon
-nitrogen
-phosphorus
-sulfur
6
Q
Atom
A
Smallest piece of an element that retains the characteristics of the element
-atoms are composed of protons (+), neutrons (neutral), and electrons (-)
7
Q
Where are electrons in an atom?
A
They surround the atomic nucleus, they are in energy shells (aka orbitals)
-they are very small and very fast
8
Q
Where are protons and neutrons in an atom?
A
They are close together in the atomic nucleus (the center of the atom)
9
Q
Atomic number
A
Indicates how many protons there are in each atom of a particular element
-it is the top number above the element’s symbol
10
Q
Atomic mass
A
The number of protons and neutrons in an atom’s nucleus
-is is the number on the bottom below the element symbol
11
Q
Anion
A
A negatively charge ion
12
Q
Isotopes
A
Different forms of the same element (same atomic number but different atomic mass)
-the number of neutrons may vary among atoms of the same element
13
Q
3 isotopes of carbon atom
A
-carbon 12= 6 protons, 6 neutrons and 6 electrons (99% of carbon atoms)
-carbon 13= 6 protons, 7 neutrons, and 6 electrons
-carbon 14= 6 protons, 8 neutrons, and 6 electrons
14
Q
Atomic weight
A
The average mass of all atoms of an element
15
Q
Atom are organized into…
A
Molecules
16
Q
What links atoms together?
A
Chemical bonds link atoms into a molecule
17
Q
Energy shells
A
Also known as orbitals
-contains atom’s electrons
-they exist at various distances from the atom’s nucleus
-the shell farthest from the nucleus is important for bonding
18
Q
Electrons are arranged in…
A
Pairs
-unpaired electrons form bonds with other atoms
-atoms are most stable when their outer shells have no vacancies
-vacancies make the atom less stable, and more likely to bond with other atoms
19
Q
Covalent bonds
A
Form when atoms share electrons
-two types are polar and nonpolar covalent bonds
20
Q
Double bonds
A
Covalent bonds that share 4 electrons between 2 atoms (ex. oxygen O2)
21
Q
Water is held together by…
A
A single covalent bond, each with 2 electrons (H2O)
22
Q
Valence shell
A
The outer most occupied energy shell
-atoms are most stable when the valence shell is full
23
Q
Electronegativity
A
Measures the atoms ability to attract electrons
24
Q
Periodic table arranges atoms by…
A
Electronegativity
-vertically going up: increase electronegativity and decrease in atomic radius
-horizontally going to the right: increase electronegativity and decrease atomic radius
25
Nonpolar covalent bonds
Type of bond that forms when atoms have similar electronegativities (ex. methane)
-in methane (CH4) all atoms equally share electrons, neither pulls stronger than the other
-electronegativity difference is less than 0.4
26
Polar covalent bonds
Type of bond that forms when atoms have different electronegativities (ex. water H2O)
-in water (H2O) oxygen atoms pull the electrons closer to it because it attracts them stronger than the hydrogen atoms can. This leaves oxygen slightly negative and hydrogen slightly positive because electrons have a negative charge
-electronegativity difference is 0.4-1.7
27
Hydrogen bonds
Always with hydrogen and always with molecules
-weak bond
-hydrogen (slightly positive) attracts oxygen (slightly negative)
-hydrogen bonds gives water is emergent properties
-hydrogen bonds give water a collection of unique properties and are important in protein and DNA structure
28
Ionic bonds
Type of bond that forms when atoms have such a dramatic difference in electronegativity that one atom completely pulls an electron away from another atom
-strong but breaks easily in water
-atom that loses electron becomes positively charged
-atom that gains electron becomes negatively charged
-both atoms achieve full outer energy shells, leaving no vacancies in either atom, which makes atoms more stable
-electronegativity difference is more than 1.7
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Solvent
Chemical in which other substances dissolve in
30
Solute
Chemical that dissolves in a solvent
31
Solution
A mixture of a solute dissolved in a solvent
32
Chemical reaction
Interaction in which bonds break and new bonds form, atoms swapped, energy released or used for form products
33
Reactant
Starting material in a chemical reaction
34
Product
The result of a chemical reaction
35
Unique properties of water
-cohesive
-adhesive
-excellent solvent
-excellent solvent for salt
-only dissolves selected molecules
-regulates temperature
-expands when freezes
36
Water Cohesion
The tendency of water molecules to stick to one another
-cohesion between molecules on the surface of liquid water gives it high surface tension
37
Water Adhesion
A process in which water molecules form hydrogen bonds with other molecules (ex. paper towels soaking up water)
38
Cohesion and adhesion allow water to...
It allowed water molecules to "climb" from a tree root to its highest leaves
39
Water is an excellent solvent
Water dissolves hydrophilic (water loving) substances (polar solutes and ions)
-the polarity of water molecules helps dissolve most biologically important molecules, since many of them are hydrophilic
40
Water is an excellent solvent for salt (NaCl)
-the slight negative charge of water attracts positive changes (Na+)
-the slight positive charge of water attracts negative charges (Cl-)
41
Water only dissolves selected molecules
-water doesn't dissolve hydrophobic (water fearing) substances
-the molecules in lipids, like butter, have nonpolar covalent bond
42
Water regulates temperature
Hydrogen bonds make water resist changes in temperature (cools and heats very slowly)
43
Water expands when it freezes
Hydrogen bonds make water molecules spread out at water freezes into ice
-because it's spread out, ice is less dense than liquid water, so ice will float to the top
-in large bodies of water, a top layer of ice provides insulation and keeps the rest from freezing underneath, making it possible for aquatic life to survive in the winter
44
Water participates in chemical reactions needed for life
It's a reactant in reactions that build and break down all classed of biological molecules (ex. nucleic acids)
45
Ph scale
A scale that shows the amount of H+ (hydrogen) ions in s solution (moles per liter)
46
Acidic solutions
Low Ph, less than 7
-has a high H+ (hydrogen) concentration
-it adds H+ to a solution
47
Basic solutions
High Ph, more than 7
-a low H+ (hydrogen) concentration
-have more OH- (hydroxide ion) than H+
-either absorb H+ ions or release OH-
48
Neutral Ph
7 Ph is neutral
-many organisms maintain a Ph homeostasis close to Ph 7, if it strays too far, it could die
49
Buffer solutions
A solution to help maintain a constant Ph by absorbing to releasing H+ ions into a solution
-when Ph is too high, buffers release H+ ions to lower Ph
-when Ph is too low, buffers absorb H+ ions to raise Ph
50
Organic molecule
A molecule that contains both carbon and hydrogen (ex. methane)
-organic molecules are biologically important, needed for life's processes and categorized into 4 main types
51
4 main types of organic molecules
-carbohydrates
-proteins
-nucleic acids
-lipids
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Macronutrients
Nutrients required in large amounts
53
Types of carbohydrates
-simple sugars
-polysaccharides
-complex carbohydrates (cellulose, chitin, starch, and glycogen)
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Types of lipids
-triglycerides
-phospholipids
-steroids
-waxes
55
Simple sugars
Carbohydrates
-chemical structure: monosaccharides and disaccharides
-function: to provide quick energy
56
Complex carbohydrates
-cellulose, chitin, starch, and glycogen
-chemical structure: polysaccharides (polymers of monosaccharides)
-function: support cells and organisms (cellulose and chitin)
-function: store energy (starch and glycogen)
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Proteins
-chemical structure: polymers of amino acids
-function: carry out nearly all the work of the cells
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Nucleic acids
DNA and RNA
-chemical structure: polymers of nucleotides
-function: store and use genetic information and transmit it to the next generation
59
Lipids
A collection of different hydrophobic molecules
-different groups of lipids include molecules with varying structures and functions
-unlike carbohydrates, proteins, and nucleic acids, lipids are not built from chains of monomers
60
Triglycerides
Lipids (fats and oils), energy rich
-formed by covalently attaching 3 fatty acids to a glycerol molecule
-chemical structure: glycerol and 3 fatty acids
-function: store energy long term
61
Phospholipids
Lipids
-chemical structure: glycerol, 2 fatty acids, and phosphate group
-function: form major part of biological membranes
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Steroids
Lipids
-chemical structure: 4 fused rings, mostly of carbon and hydrogen
-function: stabilize animal membranes and sex hormones (ex. testosterone)
-cholesterol regulates the fluidity of animal cell membranes
63
Waxes
Lipids
-chemical structure: fatty acids and other hydrocarbons or alcohol
-hydrophobic
-function: provide waterproofing seals (ex. cuticle the stops the leaves of drying out)
64
Monomers
A single unit of a carbohydrate, protein, or nucleic acid
-monomers join to form polymers
65
Oligosaccharides
Intermediate length carbohydrate consisting of 3-100 monosaccharides
66
Dehydration synthesis
A type of chemical reaction that joins monomers together into polymers
-to synthesis a polymer, enzymes form bonds between two monomers
-a water molecule is released as a part of the chemical reaction
-binds 2 monosaccharides together, forming a disaccharide (2 sugars) (ex. sucrose is a disaccharide)
67
Hydrolysis
A type of chemical reaction that breaks polymers apart into monomers
-to "digest" or break down a polymer, enzymes break bonds between the monomers
-a water molecule is required for the reaction to occur
-separates disaccharides into monosaccharides
68
Monosaccharides
Simple sugars
-the monomers that make up larger carbohydrates
-ex. ribose, glucose and fructose
69
Polysaccharides
A long chain of carbohydrates, many sugars
-hundreds to thousands of monosaccharide monomers
70
Cellulose structure
Starch energy and glycogen energy
71
R-group
An amino acid side chain
72
Protein structures and functions
-the "workers" of the cells, they do almost everything
-proteins, like collagen, create cellular structures
-proteins, like actin and myosin, produce muscle contractions
73
Proteins are made of...
Amino acids (monomers of proteins)
-there are 20 different amino acids in nature
-all amino acids have the same general structure
74
Each amino acid has its own chemical and physical properties
The 20 different amino acids have 20 different R-groups
-some are polar, some are nonpolar, some are charged
-some are small, some are medium, some are bulky
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Peptide bond
A covalent bond between adjacent amino acids
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Proteins: synthesis and breakdown
-dehydration synthesis binds 2 amino acids together forming a dipeptide (2 amino acids)
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Polypeptide
A long chain of amino acids (100+)
-fold up into a unique 3D shape to become a protein
78
The function of a protein depends on...
It's shape, or tertiary structure
79
Denatured proteins
Lose their shape
-raw egg (normal, functional protein) >heat> cooked egg (denatured, nonfunctional protein)
80
Different protein structures
-primary structure
-secondary structure
-tertiary structure
-quaternary structure
81
Protein: primary structure
Sequence
-amino acids sequence of a polypeptide
82
Protein: secondary structure
Substructure
-localized area of coils, sheets, and loops within a polypeptide
-ex. alpha helix and beta sheet
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Protein: tertiary structure
Polypeptide shape
-overall shape of 1 polypeptide
84
Protein: quaternary structure
Protein shape
-overall protein, arising from interactions between multiple polypeptides that make up a functional protein
-only proteins with multiple polypeptides have quaternary structure
85
The primary structure of each protein in a cell is determined by...
The nucleic acids
-monomers of nucleic acids are nucleotides
86
3 parts of a nucleotide
-a phosphate group
-a 5-carbon sugar
-a nitrogenous base (5 possible nitrogenous bases)
87
Nitrogenous base: DNA and RNA
Both incorporate adenine, cytosine, and guanine
87
Different nitrogenous bases are found in...
Nucloetides
87
Nitrogenous base: DNA
Uses thymine
87
Nitrogenous base: RNA
Uses uracil
87
Nucleic acids: synthesis and breakdown
-dehydration synthesis binds 2 nucleotides together
-hydrolysis separates nucleic acids into individual nucleotides
87
Saturated fatty acid
Triglycerides
All the hydrogens it possibly can
-all carbons of a saturated fatty acid are bonded to 4 other atoms (this makes the fatty acid have a straight shape)
-ex. butter (solid at room temperature)
87
Glycerol
3-carbon molecule that forms the back bone of triglycerides and phospholipids
-2 saturated fats and 1 unsaturated fat
87
DNA and RNA are long chains of...
Nucleotides
87
DNA
-deoxyribonucleic acid
-double strand of nucleotides
-includes deoxyribose
-has thymine
87
Unsaturated fatty acid
Triglycerides
Has at least 1 double bond between carbon atoms (this makes the fatty acid have a bent shape)
-bends in the unsaturated fatty acids prevent them from packing close together
-ex. vegetable acid (liquid at room temperature)
87
Triglycerides: synthesis and breakdown
-dehydration synthesis links the fatty acids to the glycerol, forming a triglyceride
-hydrolysis separates fatty acids from glycerol
87
RNA
-ribonucleic acid
-a single strand of nucleotides
-includes ribose
-has the nitrogenous base uracil
