Term
| In Griffith's experiments, what allowed the live R strain and the heat killed S strain to kill mice when injected together? |
|
Definition
|
|
Term
| What forms each DNA nucleotide? |
|
Definition
| Deoxyribose sugar, phosphate group, nitrogenous base |
|
|
Term
| What are the purines and pyramidines? |
|
Definition
Purines : Adenine + Guanine
Pyamidines : Thymine + Cytosine |
|
|
Term
| What is the linkage between nucleotides called? |
|
Definition
|
|
Term
The DNA backbone is...
A. Positive
B. Negative
C. Neutral |
|
Definition
|
|
Term
| What forces stabilize the double helix? |
|
Definition
| Hydrogen bonding, base stacking interactions |
|
|
Term
| Why is separation of strands during DNA replication possible? |
|
Definition
| The bonds holding them together are relatively weak (Van der Waal forces) |
|
|
Term
| What is the currently proven method of DNA replication? |
|
Definition
|
|
Term
| How many origins of replication are there during DNA replication in a) prokaryotes and b) eukaryotes? |
|
Definition
|
|
Term
| How does DNA polymerase work in DNA replication? |
|
Definition
| Adding nucleotides to the 3' end of daughter strand |
|
|
Term
| What does DNA helicase do? What is a side effect of this? |
|
Definition
| Unwinds the double helix by breaking hydrogen bonds between bases; this causes helix to twist more tightly beyond replication fork |
|
|
Term
| What relieves the tight coiling caused by helicase? |
|
Definition
|
|
Term
| What prevents strands from coming together again during DNA replication? |
|
Definition
| Single stranded binding proteins |
|
|
Term
| What is the role of primase in DNA replication? |
|
Definition
| It removes binding proteins and makes a short complementary RNA primer (5'-3' direction) |
|
|
Term
| What is the difference between DNA polymerase I and III? |
|
Definition
I - removes primer from the next okazaki fragment and fills the gap with nucleotides
III- extends the RNA primer |
|
|
Term
| Which enzyme repairs the nick in the DNA backbone on the lagging strand? |
|
Definition
|
|
Term
| What happens to unrepaired replication errors? |
|
Definition
|
|
Term
| What is 3'-5' exonuclease? |
|
Definition
| Proofreading mechanism in DNA polymerase; can remove and replace an incorrect nucleotide |
|
|
Term
| What causes incorrect base pairing? |
|
Definition
| Bases alternate between different isomers; it is a different base at the moment that polymerase comes to it |
|
|
Term
| What are two problems with mispaired bases? |
|
Definition
1. alter DNA's diameter
2. can't properly hydrogen bond |
|
|
Term
| Do genes code for proteins? |
|
Definition
| No - they code for polypeptides |
|
|
Term
| Where does transcription occur in a) prokaryotes and b) eukaryotes? |
|
Definition
|
|
Term
| What are the stages of transcription? |
|
Definition
| Initiation, elongation, termination |
|
|
Term
| Where is a TATA box found? |
|
Definition
|
|
Term
| How is transcription initiated? |
|
Definition
| Transcription factor proteins bind to promotor and recruit RNA polymerase |
|
|
Term
| What are three differences between DNA and RNA? |
|
Definition
1. DNA must stay in the nucleus
2. RNA uses ribose, DNA uses deoxyribose
3. Uracil replaces thymine in RNA |
|
|
Term
| Where would you find a polyadenelation signal in transcription? |
|
Definition
|
|
Term
| Why is the genetic code called degenerate or redundant? |
|
Definition
| 18 amino acids are coded for by multiple codons |
|
|
Term
| Are there spaces or markers between codons? |
|
Definition
|
|
Term
| How many correct reading frames are there? |
|
Definition
|
|
Term
| What is the function of the guanine cap on mRNA? Where is it found? |
|
Definition
| Initial attachment site for ribosomes; found at 5' end of eukaryotic mRNA |
|
|
Term
| What protects eukaryotic mRNA against RNA digesting enzymes in the cytosol? |
|
Definition
| Poly (A) tail - sequence of 50-250 adenine nucleotides on 3' end |
|
|
Term
| What is the spliceosome composed of? |
|
Definition
| pre-mRNA and small ribonucleoprotein particles (snRNPs) |
|
|
Term
| Where is the catalytic activity in the spliceosome? |
|
Definition
|
|
Term
| What does mRNA splicing remove? What does it leave behind? |
|
Definition
| Removes non-coding introns, leaving exons and joining them together |
|
|
Term
| What is the advantage of mRNA splicing? |
|
Definition
| Increases proteome without increasing genome through alternative splicing and exon shuffling |
|
|
Term
| What is the purpose of transfer RNA? |
|
Definition
| It can associate with both mRNA and an amino acid |
|
|
Term
| What causes tRNA's cloverleaf structure? |
|
Definition
|
|
Term
| What does aminoacylation do? |
|
Definition
| Pairs the correct amino acid with tRNA (also adding free energy) |
|
|
Term
| How many aminoacyl-tRNA synthetase enzymes are there? |
|
Definition
|
|
Term
| What does Crick's Wobble hypothesis account for? How does it work? |
|
Definition
| 20 enzymes can read 61 codons because the third base can pair more flexibly than the first two. |
|
|
Term
| How many ribosomes are in mammalian cells? |
|
Definition
|
|
Term
| When do the small and large ribosomal subunits come together? |
|
Definition
|
|
Term
| From 5' to 3', which order are the ribosome sites in? |
|
Definition
| E (exit), P (peptidyl), A (aminoacyl) |
|
|
Term
| At which site of the ribosome is the amino acid cleaved from tRNA? |
|
Definition
|
|
Term
| What is the rate of elongation in a) prokaryotes and b) eukaryotes? |
|
Definition
a) 15-20 cycles/second
b) 1-3 cycles/second |
|
|
Term
| How is translation terminated? |
|
Definition
| A stop codon reaches the A site of the ribosome |
|
|
Term
|
Definition
| Entire structure of mRNA and multiple ribosomes |
|
|
Term
| What are three example of initial protein modifications? |
|
Definition
1. addition of organic groups
2. removal of amino acids
3. folding, assisted by chaperones (helper proteins) |
|
|
Term
| Where do proteins go if they are made on free ribosomes and have no signal? |
|
Definition
|
|
Term
| Why do nuclear proteins retain their signal sequence? |
|
Definition
| They must re-enter the nucleus every time it dissolves and reforms during cell division |
|
|
Term
| What happens in contranslational transport? |
|
Definition
| A signal sequence on a protein temporarily stops translation until a signal recognition particle recognizes it and docks the ribosome to the ER membrane. The protein is then pushed into the ER lumen as it is translated. |
|
|
Term
| Are prokaryotic and eukaryotic routing signals the same? |
|
Definition
| Yes - they are interchangeable |
|
|
Term
| What is the source of new alleles? |
|
Definition
|
|
Term
True or false:
1. environmental factors can increase the rate of mutations.
2. Mutations occur as the organism tries to adapt to the environment.
3. Mutations may be predicted. |
|
Definition
|
|
Term
| Which mutations get passed down to offspring? |
|
Definition
|
|
Term
| What are two endogenous sources of mutations? |
|
Definition
| Unrepaired DNA replication errors; byproducts from cell metabolism (free radicals) |
|
|
Term
| Do small scale mutations affect whole chromosomes? |
|
Definition
|
|
Term
| What is the difference between a missence and a nonsense mutation? |
|
Definition
| Missense will create a different protein by replacing one amino acid with a different one; in a nonsense mutation the protein is incomplete because an amino acid was replaced with a stop codon |
|
|
Term
| What would a deletion or addition mutation result in? |
|
Definition
|
|
Term
| Why would a hydrogen atom be added to a reduced molecule? |
|
Definition
| To neutralize its charge, making it less reactive with surrounding tissues |
|
|
Term
| The more highly reduced a molecule is, the ____ potential energy it possesses. |
|
Definition
|
|
Term
More energy is stored in an electron ____ from the nucleus.
a) further
b) closer |
|
Definition
|
|
Term
Each molecule in an electron transport chain is ____ electronegative than the molecules before it.
a) less
b) more
c) the same |
|
Definition
|
|
Term
| Where are electron transport chains located? |
|
Definition
| The folded inner membrane of mitochondria or chloroplasts |
|
|
Term
| Can kinetic energy be used for work? Can heat energy? |
|
Definition
|
|
Term
| Which is a quicker process, combustion or cellular respiration? Why? |
|
Definition
| Combustion - cellular respiration releases energy bit by bit so that it doesn't burn the surrounding tissue |
|
|
Term
| Is photosynthesis a catabolic or anabolic reaction? Why? |
|
Definition
| Anabolic - it builds glucose |
|
|
Term
| What percentage of energy is wasted as heat in cellular respiration? |
|
Definition
|
|
Term
| Where does glycolysis occur? |
|
Definition
|
|
Term
| In the energy investment phase of glycolysis, why are phosphate groups added to glucose? |
|
Definition
|
|
Term
| What is the net yield of glycolysis? |
|
Definition
|
|
Term
| What is the first step of the energy liberation phase of glycolysis? |
|
Definition
| Cleavage phase - fructose-1,6-phosphate is split into two molecules of G3P, releasing two H+ ions and two electrons |
|
|
Term
| Is the reduction of NAD+ endergonic or exergonic? |
|
Definition
|
|
Term
| What are the two carbon molecules left at the end of glycolysis called? |
|
Definition
|
|
Term
| What is pyruvate oxidation? |
|
Definition
| Conversion of pyruvate to acetyl-CoA |
|
|
Term
| Why is the carboxyl group of pyruvate released as C)2 in a decarboxylation reaction? |
|
Definition
| The carboxyl group contains little potential energy |
|
|
Term
In pyruvate oxidation, after decarboxylation, the remaining carbons are _____ producing ____.
a) reduced; acetyl-CoA
b) reduced; acetate
c) oxidized; acetyl-CoA
d) oxidized; acetate |
|
Definition
|
|
Term
| What reacts with the acetyl group of acetate to form acetyl-CoA? |
|
Definition
|
|
Term
| How many enzyme-catalyzed reactions compose the citric acid cycle? |
|
Definition
|
|
Term
| What are the products of the citric acid cycle? |
|
Definition
| 2 CO2, 3 NADH, 1 FADH2, 1 ATP |
|
|
Term
| How many turns of the citric acid cycle occur for each glucose? |
|
Definition
|
|
Term
| Where is the respiratory electron transport chain found? |
|
Definition
| Inner mitochondrial membrane folds (cristae) |
|
|
Term
| The respiratory E.T.C. facilitates the flow of electrons from ____ to _____. |
|
Definition
|
|
Term
| What do ubiquinone molecules carry through the inner mitochondrial membrane? |
|
Definition
|
|
Term
| The proton gradient across the inner mithondrial membrane has potential energy. What is this energy called? |
|
Definition
|
|
Term
| What is the ability to use proton motive force to do work called? |
|
Definition
|
|
Term
| What is the difference between substrate level phosphorylation and oxidative phosphorylation? |
|
Definition
Substrate level: occurs in glycolysis
Oxidative: occurs in the electron transport chain |
|
|
Term
| Which method of ATP synthesis relies on ATP synthetase? What does ATP synthetase do? |
|
Definition
| Oxidative phosphorylation; forms a channel for H+ ions to flow down concentration gradient into mitochondrial matrix and uses that flow to catalyze the conversion of ADP to ATP |
|
|
Term
| The basal unit, stalk and headpiece compose which structure? |
|
Definition
|
|
Term
| Electron transport and chemiosmosis are uncoupled by ______ that let protons leak through the membrane. |
|
Definition
|
|
Term
| For each NADH oxidized (___ electrons), ___ H+ are pumped |
|
Definition
|
|
Term
| What is the total net yield of ATP per glucose? |
|
Definition
|
|
Term
| What percentage of energy from glucose is converted to ATP? |
|
Definition
|
|
Term
| How do ATP, ADP, and ions pass through the outer membrane of the mitochondria? |
|
Definition
|
|
Term
| What does ATP-ADP translocase allow? |
|
Definition
| Molecules to pass through inner mitochondrial membrane |
|
|
Term
| Why don't mitochondria work in the absence of oxygen? |
|
Definition
| They require oxygen as the final acceptor in the electron transport chain. |
|
|
Term
| Which molecule is used as the electron acceptor in fermentation? |
|
Definition
|
|
Term
| What type of fermentation occurs in animals? In yeast? |
|
Definition
|
|
Term
| What type of phosphorylation is used in fermentation? |
|
Definition
| substrate level phosphorylation |
|
|
Term
| Acetaldehyde is found in which cycle? |
|
Definition
|
|
Term
| Why is oxygen an efficient electron acceptor? |
|
Definition
|
|
Term
| Is photosynthesis endergonic or exergonic? |
|
Definition
| Endergonic; +685 kcal/mol |
|
|
Term
Photosynthesis is performed by
a)heterotrophs
b)autotrophs
c)protoautotrophs |
|
Definition
|
|
Term
Arrange the chlorophast structure from outside inwards:
stroma, thylakoid membrane, outer membranes, thylakoid lumen, intermembrane space |
|
Definition
| Outer membranes seperated by intermembrane space; stroma; thylakoid membrane; thylakoid lumen |
|
|
Term
| What are stacks of thylakoids called? |
|
Definition
|
|
Term
| What are three fates for the excited electron when a pigment absorbs a photon? |
|
Definition
1. reemmited as fluorescence
2. transferred to primary electron acceptor
3. release energy to nearby pigment molecule through inductive resonance |
|
|
Term
| Why are caratenoids and chlorophyll b called accessory pigments? |
|
Definition
| They can't donate electrons - only donate energy to chlorophyll a through inductive resonance |
|
|
Term
| What structure is composed of proteins, 2 specialized chlorophyll a molecules, and a primary electron acceptor? |
|
Definition
|
|
Term
| What composes a photosystem? |
|
Definition
| Central reaction center and a large antenna complex |
|
|
Term
| Which chlorophyll is found in photosystem I and photosystem II? |
|
Definition
|
|
Term
| What is the function of a photosystem? |
|
Definition
| To trap photons and oxidize a reaction center chlorophyll |
|
|
Term
| How many photons of light are required to make 1 molecule of oxygen? |
|
Definition
|
|
Term
| What are the three steps of the Calvin cycle? |
|
Definition
1. carbon fixation
2. reduction
3. regeneration |
|
|
Term
| In carbon fixation, what combines with a carbon atom from CO2 to make 2 three carbon molecules? |
|
Definition
|
|
Term
| What molecule provides the electrons for the reduction phase of the Calvin cycle? |
|
Definition
|
|
Term
| How many turns of the Calvin cycle are required to make one extra molecule of G3P? Where do the other carbons go? |
|
Definition
| 3; 5 out of 6 carbons in each turn of the cycle go to regenerate RuBP |
|
|
Term
| What is phosphofructinase? |
|
Definition
| A key enzyme in glycolysis - allosteric enzyme |
|
|
Term
Which of the following molecules, in high concentration, inhibit phosphofructinase? Which ones stimulate it?
FADH2, ATP, AMP, NAD+, NADH, Citrate |
|
Definition
Inhibit: ATP, citrate
Stimulate: AMP |
|
|
Term
| Where do a) glycolysis b) pyruvate oxidation + citric acid cycle c) electron transport chains occur in prokaryotes? |
|
Definition
a) cytosol
b) cytoplasm
c) plasma membrane |
|
|
Term
True or false:
Some bacteria can take electron directly from inorganic molecules. |
|
Definition
|
|
