Chapter 2 Flashcards
What are elements?
Elements contain only one type of atom Pure substances that cannot be broken down
- 118 known elements:
- 94 occur naturally.
- 24 have been created artificially in the laboratory.
what’s a positively charged ion?
atom that lost electron
what’s a negatively charged electron?
atom that gained electron
what do protons + electrons contribute to?
charge
define orbital
region where electron is found at least 90
percent of the time
what are reactive atoms?
have unpaired electrons in their outermost (valence) shell.
what are chemical bonds?
attractive force that links atoms together to form molecules
define covalent bonds
Can share valence electrons
Covalent bonds are very strong—a lot of energy
is required to break them.
define ionic bonds
Ionic bonds are formed by the electrical attraction of
positive and negative ions.
Eg- NaCl
define nonpolar covalent bonds
A covalent bond between atoms that have the
same, or nearly the same, electronegativity is a
nonpolar covalent bond.
atoms share the electrons equally.
is water polar or non polar
polar molecule
pH of water?
7
mention some uniquely unusual properties of water
- Moderation of Temperature
- Cohesion & Adhesion
- Ability to Act as an Insulator
- Ideal Solvent
- Weak Acid
what type of bonds is present in water?
Hydrogen bonds
Due to which of water’s properties does earth maintain a moderate temperature?
high heat capacity - moderation of temperature
explain cohesion in water
water molecules resist coming apart
from one another.
• Results in surface tension.
• Helps water move through plants (wicking)
what are the 4 major elements?
C,O,H,N
special property of Carbon?
Carbon is 47% of that dry mass. Carbon has the unique
ability to combine with a wide variety of molecules
what are organic molecules?
molecules that contain carbon
carbon containing molecules are very diverse
true or false
true
define isomers
Two molecules with the same chemical formula may
be arranged differently
subunits of proteins?
amino acids
main function of functional groups and some examples
add chemical character to carbon chains
what are the subunits of nucleic acids such as DNA or RNA called?
nucleotides
name the 3 components of nucleotides
five-carbon sugar (ribose or deoxyribose)
base containing nitrogen
one or more phosphate groups
how does the sugars differ in nucleotides?
The sugars differ only by the OH group or H group
at the 2′ carbon
name the pyramidine bases
Cytosine C
Uracil U
Thymine T
name the purine bases
Guanine G
Adenine A
what’s the bond between nucleotides called?
Phosphodiester bond
give carbohydrates structure
C6H12O6
what are the types of sugar molecules?
cyclic glucose
linear glucose
what’s name of the bond that holds carbohydrates?
Glycosidic bonds
how are lipds made?
fatty acids
what’s a triacylglycerol?
formed by addition of 3 fatty acid chains to glycerol
what’s an unsaturated fatty acid?
contains one/ more carbon, double bonds
what are van der waal’s forces?
How are steroids formed?
Steroids are composed of many carbon atoms
bonded to form rings.
Eg- Cholesterol (a steroid) is a precursor steroid
hormones such as estrogen and testosterone.
what are phospholipids?
contains hydrophillic head and hydrophobic tails
Could these building blocks have been
generated on early earth?
How did the building blocks
form macromolecules?
