Unit 1
Define the following terms: Scientific Law, Scientific Theory, Hypothesis
Hypothesis - A testable question developed by a
scientist based on a series of observations. A good
hypothesis makes testable predictions.
Scientific Theory - An explanatory idea that is broad
in scope and supported by the results from many
experiments designed to test hypotheses. It is not
simply a guess.
Scientific Law - A theory that has withstood repeated
testing and is accepted as being true in all cases.
What is the difference between hydrophobic and hydrophilic? What parts of the phospholipid bilayer are hydrophobic and hydrophilic?
hydrophobic-water fearing. non polar molecules do not have strong interactions with water and therefore do not dissolve in water. (phospholipid tails)
hydrophilic- water loving. polar molecules dissolve in water because they have strong interactions with water. (phospholipid heads)
What are the main differences between prokaryotes and eukaryotes?
Prokaryotes-lack a nucleus. they have no internal membrane bond organelles.
Eukaryotes-have a nucleus and membrane bond organelles.
What is the Central Dogma and what order does the process of DNA replication flow in?
Central Dogma is the flow of genetic information.
DNA->Transcription->RNA->Translation->Protein
If we are told that there is 30% of base A, what is the percentage of the other bases?
T-30%
G-20%
C-20%
• complexity, with precise spatial organization on
several scales
• ability to change in response to the environment
• abilities to metabolize and to reproduce
• capacity to evolve
What are the organic molecules and what are their monomers?
Proteins-amino acids
Nucleic acid-nucleotides
Carbohydrates- sugars
Lipids-fatty acids
**Remember: carbon is the backbone of all organic molecules**
What is the difference between micelle and bilayer when talking about lipid structure? What direction do lipids move in?
Micelle-large hydrophilic head and a single hydrophobic tail. spherical shape
Bilayer-the membrane. a hydrophilic head on either side and two pairs of hydrophobic tails in the middle
Lipids move laterally within the membrane.
What are the building blocks of nucleic acids? What are the four bases and how many hydrogen bonds do they form together?
Phosphate group, deoxyribose sugar, base
A-T: 2 hydrogen bonds
G-C: 3 hydrogen bonds
Describe the structure of amino acids.
Center carbon covalently bonded to a amino group, carboxyl group, side chain R group, and a hydrogen
What are the two laws of thermodynamics?
First Law- energy can not be created or destroyed. it can only be transformed from one form into another
Second Law- the degree of disorder (# of possible positions and motions of a molecule) in the universe tends to increase
What are the four types of chemical bonds and what makes each different?
Covalent-two atoms share a pair of electrons
Polar Covalent- non-equal sharing of electrons between two atoms, leading to charge difference (nonpolar has equal sharing and no charge difference)
Hydrogen-bond between hydrogen and another atom. Hydrogen will form polar bonds with oxygen and nitrogen but non-polar with carbon.
Ionic-complete transfer of an electron. formed by attraction between ions of opposite charges.(cations and anions)
What is the difference between saturated and unsaturated fats? What is the impact of cholesterol?
Saturated are tightly packed and have all single bonds between carbons. Unsaturated have a double bond between one carbon causing a kind and and reducing the tightness of packing.
Cholesterol affects membrane fluidity (acts as a 'buffer') and is amphipathic. (refer to graph)
What is the RNA strand what would be transcribed by the following DNA sequence? What is the template strand?
'5 ATGCTAGCC3'
3'TACGATCGG 5'
5'AUGCUAGCC 3'
Find the amino acid sequence from the follow DNA strand.
'5 TGAATGCTAGCC3'
3'ACTTACGATCGG 5'
5'AUGCUAGCC 3'
met-leu-ala
What are the essential cell features?
1. An ability to store and
transmit information.
2. A plasma membrane that
creates a distinct boundary
separating the cell interior
from the external
environment
3. An ability to harness
materials and energy from
the environment
What is electronegativity?
The ability of an atom to attract a
shared pair of electrons in a covalent bond more than its partner atom.
What proteins are present in the membrane and what are their purposes?
-transporters: that move ions and molecules.
-receptors: that allow the cell to receive signals from
the environment.
-enzymes: that catalyze chemical reactions in the
cell.
-anchors: that attach to other proteins.
(refer to diagram)
How is transcription initiated? When will it end?
Describe the following protein structure. Primary, Secondary and Tertiary
Primary-blocks on a string, polypeptide chain, a bunch of amino acids covalently bonded together
Secondary- alpha helix (carboxyl group and amino group bonded together 4 amino acids apart) and beta sheets (carboxyl group and amino group bonded together in parallel or antiparallel)
Tertiary- final folded shape determined by secondary structure, interactions between R groups, distribution of hydrophobic and hydrophilic groups
Describe what you know about the plasma membrane.
1.Plasma membrane separates
the living material within the cell
from the nonliving environment
around it, and controls exchange
of material between the cell and
the environment.
2.Some cells have internal
membranes that divide the cell
into compartments.
3.Some cells have a nucleus
(eukaryotes) and others do not
(prokaryotes).
The chemical reactions required to sustain life are collectively referred to as:
-anatomy
-genetics
-metabolism
-physiology
-all of the above
metabolism
How would you define the following modes of transport across the membrane? Simple Diffusion, Facilitated Diffusion, Primary Active Transport, Secondary Active Transport
Simple Diffusion-movement of molecules from high concentration to low concentration. small, hydrophobic molecules can get through this way. does not require protein channel or carrier.
Facilitated Diffusion-movement down the concentration gradient using a protein channel or carrier. polar molecules can get through this way.
Primary Active Transport-ATP is used to move molecules against concentration gradient
Secondary Active Transport-energy is stored in concentration gradient from Primary Active transport. This produces a electrochemical gradient to move molecules against concentration gradient.
What is the process of RNA splicing?
introns are non-coding regions of the RNA transcripts.Introns are removed and exons are spliced together. Alternative splicing is possible and will result in a different but related protein product in different cells.
What are the three sites on ribosomes and what are their purposes?
A site-accepts tRNA (this is where tRNA will bind to first)
P site-peptide bonds are formed and amino acid chain increases
E site-tRNA exists the ribosome