Exam 3
Each new molecule of DNA is
-double stranded -antiparallel -will twist into the double helix
DNA:
-double stranded molecule that has long chain of nucleotides -deoxyribose
Fluid mosaic:
-fluid implies motion -lots of movement within
Flow of information:
-DNA > DNA -DNA > mRNA > proteins
3'-5' and 5'-3':
-DNA is double stranded -strands are anti parallel
ATP:
-adenosine triphosphate -major energy carrier in the cell -energy stored in phosphate bonds
Phosphodiester bond:
-bond that links the nucleotides in DNA or RNA -joins the phosphate group of one nucleotide to the hydroxyl group on the sugar of another nucleotide
First law of thermodynamics:
-conservation and conversion of energy -energy cannot be created or destroyed -must conserve total amount
Facilitated diffusion
Using a membrane protein to help cross the membrane, no energy required
Most chemical reactions occur in
Water
Problem with osmosis
Water is able to pass through a plasma membrane
Ionization of water (pH)
Water molecules can ionize into positive hydrogen ions and negative hydroxyl ions
Active:
Requires energy
Facilitated transport
"Helps" molecules cross the membrane; passive, no energy
"Iso"
"The same"
Structure of water:
-1 oxygen atom -2 hydrogen atoms Covalently attached together
Mater may contain:
-1 water molecule or -many water molecules reacting together
DNA dependent DNA polymerase:
-enzyme that is able to "read" nucleotide base sequences -knows which new nucleotide needs to be out into place -complementary base pairing
Parts of aerobic respiration:
-glycolysis -Krebs cycle -electron transport system
pH:
-high hydrogen ion concentration is an acid -high hydroxyl ion concentration is a base (alkaline)
Phospholipids have a:
-hydrophilic portion -hydrophobic portion
Hydrogen bonding:
-individual water molecules react with each other -relatively weak, and is easily broken and reformed
A cell that contains 20% salt is placed into a solution containing 60% water. What is the type of situation?
-inside: 20% water (which means it's 80% water) -solution: 60% water More water inside the cell that outside, water moves out: hypertonic situation
Second law of thermodynamics:
-law of entropy -without energy, all things move towards a state of disorder
Phospholipids:
-major structural components of biological membranes -glycerol + 2 fatty acids + 1 phosphate
Transcription:
-making mRNA -occurs in the nucleus of eukaryotes & in the cytoplasm of prokaryotes
Translation: (aka protein synthesis)
-making proteins -occurs at the ribosomes in all cells
Passive transport:
-molecules will follow their concentration gradients from high to low -no energy required
Below pH 7:
-more hydrogen ions -acidic
Above pH 7:
-more hydroxyl ions -basic
Hypertonic situations:
-more water inside the cell than outside -water follows concentration gradient, and moves out -will cause the cell to shrink (crenate) -the cell may die
Hypotonic situations:
-more water outside than inside the cell -water will follow its concentration gradient, and move into the cell -will cause the cell to swell (may burst)
Osmosis:
-movement of water across a plasma membrane -will follow its concentration gradient and move from high to low concentration
Phospholipid bilayer:
-phosphates face fluid inside the cell and outside the cell -lipids (fatty acids) on each layer face each other
Membrane characteristics:
-phospholipid bilayer -semi-permeable -fluid mosaic
Energy converting pathways:
-photosynthesis -aerobic respiration
DNA replication:
-semi-conservative -old stains are conserved and used as the model or template for the new strands
RNA:
-single stranded molecule that has a shorter chain of nucleotides -ribose
Aerobic respiration:
-stored energy > chemical energy -energy = ATP
Photosynthesis:
-sunlight > chemical energy > stored energy > chemical energy -energy = sunlight
Characteristics of water:
-surface tension -cohesion -temperature stability -dissolving capabilities
Importance of buffers:
-take up excess hydrogen ions -release hydrogen ions to keep pH constant
DNA replication occurs in:
-the nucleus of eukaryotic cells -the cytoplasm of prokaryotic cells
Proteins, carbohydrates, & other lipids function as:
-transporters -recognition -communication -identification markers
Active transport:
-use ATP driven pumps -goes against concentration gradient -example: sodium/potassium pump
Dissolving power of water:
-will dissolve various polar or charged molecules -will not dissolve some molecules and do not like mixing with water
Cells contain around ___% of water
70
Photosynthesis is the inverse of
Aerobic respiration
A change in pH can cause
An enzyme not to function
Chemical equation for aerobic respiration
CARBS + O2 = energy + CO2 + H2O
Chemical equation for photosynthesis
CO2 + H2O + energy = CARBS + O2
mRNA
Carries information; transcribed from DNA
Plasma membrane
Cell membrane
Aqueous organisms
Cells
DNA > mRNA > proteins
Classical flow of genetic information
Flow of genetic information is
Crucial to cell survival
Concentration gradient
Dictates how molecules move from high to low until equilibrium is reached
Passive:
Diffusion; no energy required
Aqueous environment
Extracellular fluid
Cytoplasm
Fluid inside the cell
Extracellular fluid
Fluid outside the cell
DNA
Genetic material, found in all cells
Hydrophobic
Hates water
The phosphate portion of a phospholipid is
Hydrophilic
The fatty acid portion of a phospholipid is
Hydrophobic
Isotonic situations are
Ideal situations for a cell
Hydrophilic
Likes water
Prior to cell division, the cell will
Make an exact copy of its DNA to pass along to the daughter cells
rRNA
Makes up ribosomes
Mosaic means
Many different parts
Membranes are composed of
Many different types of molecules, not just phospholipids
Semi-permeable
Membranes allow some molecules to pass and keep others out
Diffusion
Movement along a concentration gradient, no energy required
Isotonic situations
Occur when the concentration of water inside the cell is the same as outside the cell
Peripheral proteins
On one face or the other only, act as receptors
Polar covalent bonding
One part of the resulting molecule is more positive and the other is more negative
"Unwindase"
Original DNA molecule will unwind, exposing the bases on both strands
Phosphodiester bonds are formed when
Two hydroxyl groups in phosphoric acid react with a hydroxyl group on other molecules forming ester bonds
Differences between DNA and RNA
RNA: ribose sugar, bases: AUGC DNA: deoxyribose, bases: ATGC
Buffers
Resist changes in pH
DNA replication (DNA synthesis)
Semi-conservative replication
Integral proteins
Span the membrane, act as transporters (shuttles, pumps, channels)
Result of semi-conservative replication
Two identical molecules with one old strand and one new strand
pH is
The amount of hydrogen ions in a solution is termed this, for the power of Hydrogen
Information stored in DNA must be retrieved and used for
The cell to function properly
Antiparallel
The opposite arrangement of the sugar-phosphate backbones in a DNA double helix
All membranes have
The same basic structure
In isotonic situations
There will be movement, but no net charge
How ATP acts as an energy carrier
Transfers a phosphate group to another molecule (phosphorylation)
tRNA
Transports amino acids
Codon
a sequence of three nucleotides that together form a unit of genetic code in a DNA or RNA molecule
Entropy
measure of disorder