Lecture 2 Flashcards
What is biology?
The study of living things.
What are characteristics of all living organisms?
- Made of cells
- different molecular structure than living things
- sensitivity to environment
- growth, development, and reproduction
- energy utilization
- homeostasis
- evolutionary adaptation
What is homeostasis?
Maintaining a certain condition in change.
What determines function?
structure.
What are 5 levels of complexity and specificity that can be studied in biology?
- Cellular level
- Organismal level
- Population level
- Ecosystem level
- Biosphere
What is cellular level?
The level that includes atoms, molecules and organelle cells. It is the basic unit of life.
What is the organismal level?
The level that includes tissues, organs, and organ systems.
What is the population level?
The level that includes population and community.
What is the biosphere?
The ecosystem of the earth.
What is chemistry?
The study of matter.
What is matter?
Anything that has mass and occupies space.
What is matter made of?
Elements.
What is the simplest form of matter?
Elements.
What are elements made of?
Molecules.
What is one molecule of an element called?
An atom.
Which 6 elements does 99% of human body weight consist of?
- Oxygen
- Carbon
- Hydrogen
- Nitrogen
- Calcium
- Phosphorus
What are chemical bonds?
Attractive forces holding atoms together.
What are 3 kinds of chemical bonds?
- Covalent bonds - very strong (like glue)
- Ionic bonds - medium strength (Like a magnet)
- Hydrogen bonds - weak (like static)
What is energy?
the capacity to do work.
What fuels life?
energy.
What is potential energy?
Stored energy.
What is kinetic energy?
Energy in motion, doing work.
Can energy be transformed?
Yes. Kinetic energy can be transformed to potential energy and vice versa.
What is ATP?
- It is a nucleotide called adenosine triphosphate.
- universal energy source
- carries energy
What happens when bonds are broken?
Energy is released.
What partial electrical charge does Oxygen have in H2O?
A partial negative charge.
What partial electrical charge does Hydrogen have in H2O?
A partial positive charge.
How are hydrogen bonds produced?
The polarity of water allows water molecules to be attracted to one another, producing hydrogen bonds.
What is the individual strength of hydrogen bonds vs. the cumulative strength?
The individual strength is very weak, but cumulative effects are enormous.
What is responsible for many of water’s important physical properties?
Hydrogen bonds.
What is cohesion?
When water molecules stick to other water molecules by hydrogen bonding.
What is adhesion?
When water molecules tick to other polar molecules by hydrogen bonding.
What are 6 properties of water?
- Water has a high specific heat
- Water has a high heat of vaporization
- Solid water is less dense than liquid water
- Water is a good solvent
- Water organizes nonpolar molecules
- Water can form ions
What does it mean that water has a high specific heat?
It takes a large amount of energy to change the temperature of it.
What does it mean that water has a high heat of vaporization?
the evaporation of water from a surface causes the cooling of that surface.
What does it mean that water is a good solvent?
Water dissolves polar molecules and ions.
What are hydrophilic molecules?
nonpolar molecules that are ‘water loving’.
What are hydrophobic molecules?
nonpolar molecules that are ‘water fearing’.
what does it mean that water organizes nonpolar molecules?
Water causes hydrophobic molecules to aggregate or assume specific shapes.
What are the 2 ions that water can form?
- Hydroxide ion OH-
- Hydrogen ion H+
What does pH represent?
The negative logarithm of hydrogen ion concentration of a solution.
What is considered to be a neutral pH?
[H+] of 10^-7 or pH of 7
What makes a solution an acid?
When it has more hydrogen ions. (A smaller negative power means there is more hydrogen ions)
What makes a solution a base?
When it has less hydrogen ions. (A bigger negative power means there are less hydrogen ions)
What pH is considered acidic?
0-7 (10^-1 through 10^-6.9)
What pH is considered basic?
7-14 (10^-7.1 through 10^-14)
What pH is considered neutral?
7
What is a buffer?
A substance that resists changes in pH.
How do buffers work?
they release hydrogen ions when a base is added and absorb hydrogen ions when acid is added.
What do most biological buffers consist of?
Most consist of a pair of molecules, on acid and one base.
