Chap 2 Flashcards
What is the smallest component of a substance that CANNOT be divided into smaller substances without losing its properties?
Atom
The nucleus contains
protons and neutrons.
Atoms with different numbers of neutrons in their nuclei are called
isotopes.
How many electrons can be held in the second shell?
8
An isotope of oxygen has an atomic number of 8 and an atomic weight of 18. How many neutrons does it have?
10
Which type of bond is weak and does NOT bind atoms into molecules?
Hydrogen bond
The number of extra or missing electrons in an atom’s outermost electron shell is called the atom’s
valence
A bond formed from the attraction between ions of opposite charge is called a(n)
ionic bond
A molecule that contains at least two different kinds of atoms is called a(n)
compound
Which of the following is formed by the sharing of electrons between atoms to fill an electron shell?
Covalent bond
Water has an unequal distribution of charges and is called a(n)
polar molecule
Which one of the following does NOT correctly describe inorganic compounds?
a)Usually small
b)Structurally simple
c)Contain carbon
d)Include salts, acids, and bases
Contain carbon
A compound that helps keep the pH from changing drastically is
Buffer
MOST microbes grow best at a pH from
6.5-8.5
A substance that dissociates into H+ and Cl– in water is an example of a(n)
acid
In a decomposition reaction (also known as hydrolysis), sucrose can be broken down into
glucose and fructose
The following is an example of what type of reaction? AB + CD → AD + BC
Exchange reaction
Endergonic reactions ALWAYS
absorb more energy than they release.
In a synthesis reaction,
atoms, ions, or molecules are combined to form a larger molecule.
In a decomposition reaction
a larger molecule is broken down into smaller parts.
Which of the following are the “building blocks” of proteins?
amino acids
Which of the following are purines?
Adenine and guanine
Which of the following nitrogenous bases is NOT found in an RNA molecule?
Thymine
Why do saturated fats become solid more easily than unsaturated fats?
They are straight chains and pack more tightly together.
Glycogen, dextran, and cellulose are examples of
polysaccharides
Which level of protein structure refers to the overall three-dimensional structure of a polypeptide chain?
tertiary structure
Chemistry
is the study of interactions between atoms and molecules
the smallest unit of matter and cannot be subdivided into smaller substances
atom
atoms interact to form
molecules
negatively charged particles
electrons
positively charged particles
protons
uncharged particles
neutrons
Atoms with the same number of protons are classified as the same
chemical element
Each different chemical element has a different number of
protons
atomic number
: number of protons in the nucleus
is the total number of protons and neutrons in an atom
Atomic mass
of an element are atoms with different numbers of neutrons
Isotopes
are the most abundant chemical elements in living Organisms.
Hydrogen, carbon, nitrogen, and oxygen
Electrons are arranged in _______ ________corresponding to different energy levels
Electron shells
Atoms form molecules by combining to fill their
outermost shells
Molecules hold together because the valence electrons of the combining atoms form attractive forces, called
chemical bonds, between the atomic nuclei
is a molecule that contains two or more kinds of atoms
compound
The number of protons and electrons are _______ in an atom
equal
are charged atoms that have gained or lost electrons
ions
are atoms that lose electrons and become positively charged ions
cations
are atoms that gain electrons and become negatively charged ions
anions
attractions between ions of opposite charge
ionic bonds
form when two atoms share one or more pairs of electrons
covalent bonds
are stronger and more common in organisms than ionic bonds
covalent bonds
form when a hydrogen atom that is covalently bonded to an O or N atom is attracted to another N or O atom in another molecule
Hydrogen bonds
molecular mass
The sum of the atomic masses in a molecule
One mole of a substance is
its molecular mass in grams
The unit of molecular mass is a
dalton (da)
involve the making or breaking of bonds between atoms
chemical reactions
A change in _______ _______ occurs during a chemical reaction
chemical energy
reactions that absorb energy
endergonic
reactions release energy
exergonic
Occur when atoms, ions, or molecules combine to form new, larger molecules
synthesis reactions
is the synthesis of molecules in a cell
Anabolism
Occur when a molecule is split into smaller molecules, ions, or atoms
decomposition reactions
is decomposition reactions in a cell
catabolism
Are part synthesis and part decomposition
exchange reactions
The Reversibility of Chemical Reactions
Can readily go in either direction
Each direction may need special conditions
Organic compounds
always contain carbon and hydrogen; typically structurally complex
Inorganic compounds
typically lack carbon; usually small and structurally simple
important characteristics of water
1.Polar molecule
2. Solvent
3. Hydrogen bonds absorb heat
Is water organic or inorganic?
inorganic
What does it mean for water to be a polar molecule?
Unequal distribution of charges
What does it mean for water to be a solvent?
Polar substances undergo dissociation in water, forming solutes
Why are hydrogen bonds in water important?
Hydrogen bonds absorb heat
Temperature buffer
Acids
Substances that dissociate into one or more hydrogen ions and one or more negative ions
Bases
Substances that dissociate into one or more hydroxide ions and one or more positive ions
Salts
Substances that dissociate into cations and anions, neither of which is
H+ or OH-
The concentration of H+ in a solution is expressed as
pH
pH formula
pH=-log10[H+]
Increasing H+ increases
acidity
Increasing OH- increases
alkalinity
Most organisms grow best between which pH?
6.5-8.5
Why is the polarity of a water molecule important?
Makes it a good solvent
Gives it ability for hydrogen bonding which lets it absorb a lot of heat
carbon skeleton
The chain of carbon atoms in an organic molecule is the
bond to carbon skeletons and are responsible for most of the chemical properties of a particular organic compound
functional groups
In an aldehyde, C===O is at the end of a molecule, vs a ketone where
in a ketone C===O is internal
Identify the functional groups in an amino acid
NH2 amine group
COOH carboxyl group
are polymers consisting of many small repeating molecules called monomers
macromolecules
Monomers join by
dehydration synthesis or condensation reactions
Serve as cell structures and cellular energy sources
Include sugars and starches
carbohydrates
Carbohydrates consist of
C, H, and O
Formula for carbohydrates
(CH2O)n
True or false: many carbohydrates are isomers
True
Isomers
Molecules with same chemical formula, but different structures
Monosaccharides
simple sugars with three to seven carbon atoms
examples of common monosaccharides
Glucose and deoxyribose
are formed when two monosaccharides are joined in a dehydration synthesis
Disaccharides
Disaccharides can be broken down by
Hydrolysis
consist of tens or hundreds of monosaccharides joined through dehydration synthesis
Polysaccharides
Examples of polysaccharides
Starch, glycogen, dextran, and cellulose are polymers of glucose that differ in their bonding and function
Examples of dissacharides
sucrose, lactose, and maltose.
Primary components of cell membranes
Consist of C, H, and O
Are nonpolar and insoluble in water
lipids
Simples lipids
Fats or triglycerides
Simple lipids contain
Contain glycerol and fatty acids;
Simple lipids are formed by
formed by dehydration synthesis
Saturated fat
no double bonds in the fatty acids
Unsaturated fat
one or more double bonds in the fatty acids
Cis
H atoms on the same side of the double bond
Trans
H atoms on opposite sides of the double bond
Complex lipids contain
Contain C, H, and O + P, N, and/or S
Cell membranes are made of complex lipids called
Phospholipids
Structure of phospholipids
Glycerol, two fatty acids, and a phosphate group
Regions of phospholipids
Phospholipids have polar as well as nonpolar regions
Four carbon rings with an -OH group attached to one ring
Steroids
Part of membranes that keep the membranes fluid
Steroids
How do simple lipids differ from complex lipids?
simple lipids aka triglycerides contain glycerol and fatty acids and are formed by dehydration synthesis (saturated, unsaturated, cis, trans). complex lipids ARE AMPHIPATHIC and contain c h o (and n or p or S) and are made up of glycerol two fatty acids and a phosphate (phospholipid)
Which elements make up proteins?
Made of C, H, O, N, and sometimes S
Functions of proteins
essential for cell structure and function
1.Enzymes that speed up chemical reactions
2. Transporters across cell membrane
3. Flagella
4.toxins and cell structures
subunit of proteins
aminoacids
Amino acids contain an alpha-carbon that has an attached:
- Carboxyl group -COOH
- Amino group NH2
3.side group
Amino acids exist is two stereoisomers
D or L
Stereoisomers
stereoisomers are isomers that differ in spatial arrangement of atoms, rather than order of atomic connectivity.
Which stereoisomers of aminoacids are most often found in nature?
L-form
Peptide bonds
between amino acids are formed by dehydration synthesis
Primary structure
Polypeptide chain
Secondary structure
occurs when the amino acid chain folds and coils in a helix or pleated sheet
Tertiary structure
occurs when the helix or sheet folds irregularly, forming disulfide bridges, hydrogen bonds, and ionic bonds between amino acids in the chain
quarternary structure
consists of two or more polypeptides
Denaturation occurs when
proteins encounter hostile environments such as temperature and pH, and therefore lose their shapes and functions
Conjugated proteins consist of
amino acids and other organic molecules
Glycoproteins
Nucleoproteins
Lipoproteins
What two functional groups are in all amino acids?
-COOH & -NH2
subunit of nucleic acids
nucleotides
components of nucleotides
A five-carbon (pentose) sugar
Phosphate group
Nitrogen-containing (purine or pyrimidine) base
Nucleosides components
Pentose
Nitrogen-containing base
DNA stands for
Deoxyribonucleic acid
Contains deoxyribose
Exists as a double helix
DNA
In DNA, Adenine bonds with
Thymine
A is to T
In DNA, Cytosine bonds with
Guanine
C is to G
how does A bind to T and C bind to G in DNA ?
Hydrogen bonding
Order of the nitrogen-containing bases forms
the genetic instructions of the organism
Ribonucleic acid
contains
Ribose
Is single stranded
RNA
Explain the bonding of nucleotides in RNA
Adenine hydrogen bonds with Uracil
A —>U
Cytosine hydrogen bonds with Guanine
C—>G
Several kinds of R N A play a specific role in
protein synthesis
ATP stands for
Adenosine triphosphate
ATP is made of
Made of ribose, adenine, and three phosphate groups
Function of ATP
Stores the chemical energy released by some chemical reactions
How does ATP release energy?
Releases phosphate groups by hydrolysis to liberate useful energy for the cell
Which can provide more energy for a cell and why: A T P or A D P?
Adenosine triphosphate (ATP) can provide more energy for a cell than adenosine diphosphate (ADP) because it has more phosphate groups and a higher-energy bond:
Serology
the use of specific antibody binding. Helps hasten diagnosis
