exam 3
hydrophilic
phosphate heads of phospholipid is
tRNA
there is a separate _________ for each amino acid
type of molecule and the type of membrane
transport across membranes depends on the...
1 oxygen & 2 hydrogen atoms covalently attached together
water molecules are composed of
water can mean both: - 1 water molecule - many water molecules reacting together
water terminology issue
when the concentration of water inside the cell is the same as outside the cell
isotonic situations occur
energy relationship in the cell - we "make" and "use" energy all the time, but technically cannot make additional energy & cannot destroy what we have
law of thermodynamics explains the
change its form - sunlight - chemical energy - mechanical energy - work energy - heat
we might not be able to make or destroy energy but we can...
DNA dependent DNA polymerase
what enzyme moves along the original strand of DNA, "reading" the sequence of bases
"unwindase"
what enzyme will cause the original DNA molecule to unwind, exposing the bases on both strands
an acid
what is a high hydrogen ion concentration
a base
what is a high hydroxyl ion concentration
phospholipids
what is a major structural component of biological membranes?
glycerol + 2 fatty acids + 1 phosphate
what is a phospholipid composed of
a protein
what is the product of RNA translation?
5'-3' - 3'-5' is easier to read than 5'-3' - mRNA must be in the 5'-3' orientation
when DNA is converted into RNA is makes the corresponding _____ strand of mRNA
5'-3' chain & vice versa
when you copy a 3'-5' chain, you make a
maintain organization
without energy, a cell cannot...
- smaller nucleic acid used to get the information out of DNA - base sequence in DNA is converted into base sequence in RNA
RNA function
hypertonic situation inside: 20% salt = 80% water solution: 60% water
a cell that contains 20% salt is placed into a solution containing 60% water. what type of situation is this?
- sodium/potassium pump - calcium pumps - hydrogen/potassium pump
active transport examples
plasma membrane = cell membrane = phospholipids bilayer composition and function may be altered, but basics are consistent
all membranes have the same basic structure....
proteins (messenger, transfer, ribosomal)
all three types of RNA is needed to make...
tRNA (translation)
amino acids are transported by...
ribosome (translation)
base sequence of mRNA is read by the...
70%
cells contain around % water
must obtain & use energy - or they will die
cells must maintain organization, thus....
relationship between water molecules gives water all its characteristics: - surface tension - cohesion - temperature stability - dissolving capabilities
characteristics of water
- protein synthesis - location: cytoplasm, at the ribosome - base sequence in mRNA ~> amino acids sequence in protein - the sequences of bases carry the genetic information
describe translation in RNA
water will dissolve various polar or charged molecules - these are considered "hydrophilic"
dissolving power of water
- Photosynthesis: CO2 + H2O + energy ~> CARBS + O2 - aerobic respiration: CARBS + O2 ~> CO2 + H2O + energy they are the reverse of each other * energy is either ATP or sunlight
compare photosynthesis and aerobic respiration
how energy is used within the cell
define bioenergetics
- this enzyme is able to "read" nucleotide base sequences - it knows which new nucleotide need to be put into place - complementary base pairing (A-T G-C)
describe DNA dependent DNA polymerase
"DNA synthesis = semi-conservative replication" - prior to cell division (s phase of cell cycle), the cell will make an exact copy of its DNA to pass along to the daughter cells occurs: - in the nucleus of eukaryotes - in the cytoplasm of prokaryotes
describe DNA replication
making mRNA occurs: - in the nucleus of eukaryotes - in the cytoplasm of prokaryotes
describe DNA transcription & where does it occur?
making proteins occurs: at the ribosomes in all cells
describe DNA translation & where does it occur?
requires energy - must use ATP driven pumps - usually goes against a concentration gradient
describe active transport
- carbohydrates ~> ATP, electrons, & heat - Electrons ~> ATP & heat
describe aerobic reparation
- a codon is a series of 3 bases - each codon represents 1 amino acid
describe codons
"fluid": implies lots of movement within phospholipids "mosaic": implies many different molecules, not just phospholipids
describe fluid mosaic
- individual water molecules react with each other through hydrogen bonds - hydrogen bond is relatively weak, and is easily broken and reformed
describe hydrogen bonds
messenger RNA - transcribed from DNA; carries the information
describe mRNA
movement of water across a plasma membrane - water, like all molecules, will follow its concentration gradient, and move from high concentration to low concentration
describe osmosis
diffusion, no energy required - molecules follow concentration gradient from high to low - facilitated transport: "helps" molecules cross membrane
describe passive transport
sunlight ~> chemical energy ~> stored energy ~> chemical energy ~> heat
describe photosynthesis
- link the hydrogen & oxygen atoms in a water molecule - one part of the resulting molecule is more positive (2H) - the other is more negative (O) positive to negative
describe polar co-valent bonding
ribosomal RNA - makes up ribosomes - have large & small subunits
describe rRNA
membranes allow some molecules to pass and keep out others
describe semipermeable
transfer RNA - transports amino acids to the ribosome for protein synthesis
describe tRNA
- making mRNA from DNA - occurs in nucleus of eukaryotic cells - enzyme: DNA dependent RNA polymerase
describe transcription in RNA
peptide bonded
during RNA translation amino acids are ______bonded together
Photosynthesis & aerobic respiration
energy converting pathways
the phosphate bonds - major energy carrier in the cell
energy in ATP is stored in
Hydrophobic
fatty acid tails of phospholipid is
DNA ~> transcription mRNA ~> translation proteins
fill in blanks, what do the arrows mean? DNA ~> _______ mRNA ~> _______ proteins
- conservation & conversion of energy - energy cannot be created or destroyed - must conserve total amount
first law of thermodynamics
- DNA ~> DNA - DNA ~> mRNA ~> proteins
flow of genetic information
the survival of the cell
flow of genetic information is crucial to
high = base low = acid
high v.s. low pH concentration
- old strands are conserved, used as the model or template for the new strands - new molecules will each have 1 old strand and 1 new strand of nucleotides - the old molecule becomes part of the two newly produced molecules
how is DNA replication semi-conservative
there is more water inside the cell than outside the cell
hypertonic situations occur when
when there is more water outside the cell than inside the cell
hypotonic situation occur
they may die
if cells lose too much water
buffers resist changes in pH - take up excess hydrogen ions, or release hydrogen ions to keep the pH constant
importance of buffers
- animals do not photosynthesis - we make use of the sugars and starches photosynthetic organisms provide
importance of sunlight
ATP
in aerobic respiration energy =
its concentration gradient, and moves out - causing the cell to shrink (crenate)
in hypertonic situations water follows
its concentration gradient, and move into the cell - causing the cell to swell and potentially burst
in hypotonic situations water will follow
movement of molecules, but no net change
in isotonic situations there will be...
sunlight
in photosynthesis energy =
be retrieved and used for the cell to function properly
information stored in DNA must
span the membrane, act as transporters (shuttles, pumps, channels)
integral membrane proteins
water molecules can ionize into positive hydrogen ions and negative hydroxyl ions
ionization of water (pH)
each other
lipids on each layer face...
DNA - base sequence copied
mRNA is produced from
- phospholipid bilayer - semi-permeable - fluid mosaic
membrane characteristics
hydrophobic
molecules that will not dissolve in water are termed
water - we are aqueous organisms (cells) living in an aqueous environment (extracellular fluid)
most of our chemical reactions occur in ...
more hydroxyl ions, basic
pH above 7
- different enzymes have different pH requirements - change the pH, an enzyme may not be able to function
pH and enzyme activity
more hydrogen ions, acidic
pH below 7
on a scale 0 - 14, with 7 having equal hydrogen/hydroxyl ions
pH is rated on
the amount of hydrogen ions in a solution
pH is termed for
1. Glycolysis 2. Krebs Cycle 3. Electron Transport System
parts of aerobic respiration
on one face or the other only, act as receptors
peripheral membrane proteins
fluid inside the cell (cytoplasm) & outside the cell (extracellular fluid)
phosphates face....
other lipids, carbohydrates, proteins - function: as transporters, recognition, communication, identification markers
phospholipid bilayer "mosaic" composition & their function
they have hydrophilic portion and a hydrophobic portion
phospholipids are ideal biological membranes because
aerobic respiration - how we get energy from carbohydrates
photosynthesis is tied to...
water is able to pass though a plasma membrane (channel) - may be problematic for a cell, which contains water
problems with osmosis
- if you want to make a protein, you need amino acids in a particular sequence - you have all the information in DNAs sequence of bases - convert (transcribe) DNA base sequence into mRNA base sequence, then translate the mRNA base sequence into an amino acid sequence
relationships during mRNA replication
amino acids in particular order = primary structure (translation)
ribosomes calls in...
- law of entropy (disorder) - without energy, all things move towards a state of disorder
second law of thermodynamics
energy
the cell is constantly making and using
isotonic situation
the ideal situation for a cell
amino acid
there are multiple codons for each...
protein synthesis
translation is also called