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