SCI 230: Exam 1
Card Set Information
SCI 230: Exam 1
Verifiable observations and measurements
Describe life in variety of ways
Series of steps
Observations, hypothesis, experiment, result
A testable statement
"If __ occurs, then __ will result."
Has to be able to be proven false
Genus = capital letter
species = lowercase letter
4 Kingdoms in Domain Eukarya
7 Characteristics of Life
2) Grow and develop
3) Process energy
7) Evolutionary Adaptation
An observation that has been repeated confirmed and for all practical purposes is accepted as true.
A descriptive generalization about how some aspect of the natural world behaves under stated circumstances
1st Law of Thermodynamics
A well-substantiated explanation of some aspect of the natural world that can incorporate facts, laws, inferences, and tested hypothesis.
Theory of Evolution
Evidence behind it
What is meant by the phrase "science is not set in stone"?
The body of knowledge grows and science adapts to this new knowledge
Science can change (planets)
Body of science tends to be self-correcting
An apparent statistical relationship between variables
Established relationship between variables
1 unit of positive charge
Revolve around nucleus
1 unit of negative charge
Center of atom
Made up of protons and neutrons
The number of electrons in the outermost shell determines how the atom reacts
with other atoms and molecules
If the outermost shell is incomplete, then the atom or molecule is reactive
Have the same number of protons and electrons, but different number of neutrons
Determined by number of protons
Are ionic compounds that are held together by the attraction of opposite charge
Atoms/molecules with a + or – charge
Form between water molecules as they align themselves by opposite charges (H +, O -)
They stay bonded for only a short time
Each pH unit represents a 10-fold change in concentration
pH 7 = Neutral
pH 2 = Acidic
pH 8 = Base
Chemicals that releases H+ to a solution (increase the concentration (relative number) of H+ ions)
The more H+ ions, the stronger the acid
Chemical bond that accepts H+ ions and removes it from a solution (leaving behind OH- ions)
The more OH- ions, the stronger the base
What 4 elements make up 96.3% of our body weight? What 5th element is need in the molecules of life?
Oxygen, Carbon, Hydrogen, and Nitrogen
What are the 5 molecules of life given in class?
Why can isotopes be dangerous?
Some are radioactive = Nucleus decays, giving off particles and energy
Higher isotopes, more dangerous
What are the similarities and differences between ionic and covalent bonds?
Similarities = Both have complete outer shells and positive and negative charges hold them together
Differences = I bonds gain and lose electrons, but C bonds don't / I bonds form ionic compounds, but C bonds form molecules
What percentage of Earth is freshwater? What percentage is available to us?
Less than 3%
Only about 0.5%
What causes water to be a polar molecule?
The oxygen atom pulls all the electrons (water = 10e-) much more strongly to them than the hydrogen atoms, so they don’t share the electrons equally.
Electrons are mostly on the oxygen, so it shifts to the negative pole
How are hydrogen bonds differ from ionic bonds and covalent bonds?
Hydrogen bonds take place between water molecules by opposite charges
Ionic = Stronger charge
Covalent = Share electrons
Discuss the 4 unique qualities of water that make life possible on Earth with examples.
Liquid water is cohesive
- H bonds cause water molecules to stick together and pull each other up (Surface tension, moving water in trees)
Ice is less dense than liquid water
- Water molecules are spread apart, so there are less water molecules in a large space.
Water moderates temperature
- Water heats up and cools down slowly. (Evaporative cooling - sweating, Coastal Areas)
Water is the universal solvent
- Many things dissolve in water (H bonds pull Na and Cl into water.)
At what temperature is water most dense?
Most dense at 4C (39.2F)
What does pH measure?
The acidity or alkalinity of a solution on a scale in which 7 is neutral, lower values are more acidic and higher values are more basic.
What does each unit of pH represent?
It represents a tenfold change in concentration.
Lemon juice (pH-2) is 10 times more acidic than grapefruit juice (pH-3)
Multiply by 10 for each
What is the "biological range" on a pH scale?
pH 6.5 - 8.2
What is acid precipitation?
Rain, snow, or fog has a pH below 5.6.
What causes acid precipitation?
Caused by sulfur and nitrogen oxides, mostly from burning fossil fuels.
Most simple carbon molecules
Hydrogen and carbon only4 bonds for each carbon
Subunits of polymers
Molecules built by linking together a large number of subunits
“To form by removing water”
-OH and –H are removed
Making water H2O
Monomers are broken off of polymers using a process
Water is added to break the polymer
Split into –OH and –H
3 Types of Carbohydrates
Hydrogen bonds form between oxygen atoms on water or carbohydrate molecules and hydrogen atoms on the other
Large molecules attract water, small molecules dissolve in water
"Fear of water"
Molecules are repelled from water
Type of Lipid
3 fatty acids chains linked to glycerol
Main function = Energy storage
How many amino acids are in proteins?
20 Amino Acids monomers
What are the 4 classes of proteins?
Structural – Hair, tendons, silk (spiders)
Contractile – Provide movement (muscles)
Signaling – Messages within cells and from one cell to another
Enzymes – Greatly increase the rate of reactions in cells
Information storage in cells
Made up of carbon, oxygen, hydrogen,
nitrogen, and phosphorus
How many nitrogenous bases are in proteins?
There are 5 nitrogenous bases in proteins
4 Organic Molecules of Life and how each is used in organisms
Carbohydrates - Energy and structure
Lipids - Energy and structure
Proteins - Structure, enzymes, and signaling
Nucleic Acids - Storage of genetic information
Why is carbon so important in building these organic molecules?
Large amount of energy is stored in the Carbon-Hydrogen bonds
This is where most of the energy is stored in macromolecules
2 differences between hydrocarbons and carbohydrates
Carbohydrates are made up of carbon (c),
hydrogen (H), and oxygen (O) and hydrocarbons which are hydrogen and carbon only
Carbohydrates are our primary source of energy and hydrocarbons is where energy is stored, but can't use the energy
How are dehydration synthesis and hydrolysis used in cells to build and break down polymers? How is water used in each?
Polymers are built from monomers through
the process of dehydration synthesis.
- “To form by removing water”
- Making water H2O
Monomers are broken off of polymers using a process called hydrolysis
- Water is added to break the polymer
Where is most of the energy stored in both hydrocarbons and carbohydrates and fats?
Hydrocarbons store the most energy
3 Disaccharides and 1 place you might find each
Sucrose = Table sugar
Maltose = Beer
Lactose = Milk sugar
3 Polysaccharides and how each are used
Starch - Storage in plant roots and seeds, found in food (potatoes)
Glycogen - Stored in muscle cells for quick energy
Celluose - Plant cell walls, wood
What are fatty acids? How do they relate to fats and triglycerides?
C=O group plus a hyrdocarbon chain (about 15-18 carbons long)
3 fatty acids chains linked to glycerol - triglycerides (another name for fat)
What is the difference between saturated and unsatured fats?
Saturated - Fatty acids filled with the maximum number of hydrogen atoms on the carbon chain
Unsaturated - Fatty acid with less than the maximum number of hydrogen atoms on the carbon chain
Why are some fats solid at room temperature and others liquid?
Solid - Packed tightly because they are straight lined (saturated)
Liquid - Can't pack tightly because they are bent (unsaturated)
What are trans fat? Where do they come from? Why have they gotten so much attention recently?
Unsaturated fats that have been partially hydrogenated (H atoms added)
Adding H atoms often makes double bonds
in the trans configuration (across the bond)
Nutrition labels lie about having trans fats or “partially hydrogenated oils or hydrogenated oils.”
What are the 4 levels of structure in protein information?
Primary Structure -Unique sequence of amino acids / Different sequence for each protein
Secondary Structure - Interactions caused by hydrogen bonds
Tertiary Structure - Proteins automatically go into its 3D shape as they are being formed in water
What are the 2 forces that causes proteins to self-construct into their 3D shape?
Hydrophobic / hydrophilic interactions
Hydrophobic = Inside protein (get away from water), Hydrophilic = Outside protein (attract water)
Why is the 3D shape of a protein so important?
3-D shape determines the function of the proteins
What are the 3 components of DNA?
Which 2 components form the "backbone" of the molecule?
Sugar and phosphate groups
Which components form bonds across the helix?
Sugar and phosphate groups
What are the monomers and polymers for carbohydrates, lipids, proteins, and nucleic acids?