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207 Cards in this Set

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What can only be viewd by electron microscopy?
Viruses
What is true of enzymes?
They are a specific biological catalyst, were originally known as ferments, and may function separately from cells
The limit of resolution can best be defined by?
The distance that two objects must be apart in order to be distinguished as separate objects
What microscopic technique is least likely to be used to view alive, motile protozoa?
electron microscopy
What is true of a nanometer?
a nanometer is also called a millimicron
what organelle is round and derives its name from the latin work of kernel?
nucleus
What is closest to a micrometer in size?
a typical bacteria cell
gregor mendel was most influential in what field of biology
genetics
hereditary factors is an old name for?
genes
what is not a tenet of the cell theory?
all cells have a membrane bound nucleus
cell biology emerged from what field of biology?
genetics, biochemistry, and cytology
what type of microscopy has the greatest resolving power?
electron
the ___ model of DNA structure was proposed by ___
double helix, watson and crick
what biological polymer is mismatched with its monomer?
cellulose - amino acid
the heirarchical nature of cellular structure is best illustrated in what list of substances?
nucleotide, DNA, chromosome, nucleus, cell
what is not a structural polysaccharide?
glycogen
what is the best explanation for the lack of activity of the synthesized enzyme?
the synthesized enzyme was not folded correctly because molecular chaperones were not present
what is not true of phosopholipids?
sphingolipids are the predominant phosopholipid in membranes
the primary structure of a protein
all of the above
cellulose belongs to which group of macromolecules?
carbohydrates
what has the greatest number of glycosidic bonds?
amylose
hydrogen bonding is most important in stabilizing the ___ structure of many proteins?
secondary
what is not true of amino acids?
all amino acids exist in two steroisomeric forms
what is not a major functional class of proteins?
trifunctional
frederick sanger recieved a nobel prize for his work on the structure of what?
insulin
whatis not characteristic of DNA?
contains ribose
what is not a base used in DNA replication?
uracil
what is true of purines?
purines have a double ringed structure
what describes the number of carbon atoms in glucose?
hexose
what is a disaccharide?
lactose
what is not one of the six classes of lipds?
pectins
what is true of fatty acids?
saturated fatty acids have no double bonds between carbons
what is true of glycolipids?
glycolipids are usually found on the exterior surface of the plasma membrane
which of the following are components of chargaffs rules of bases?
all of the above
an example of a purine is
guanine
DNA is different from RNA in that
RNA contains an additional oxygen atom on the ribose sugar
DNA has an adenine contant of 25%. what is the %G+C in this DNA?
50%
Which of the following shoes Chargaff's equivalence?
synthetic DNA (one strand all A, the other all T)
what regarding the watson-crick model of DNA is not accurate?
it is a left-handed helix
what is not a characteristic of prokaryotic genomes?
presence of introns
you and your neighbor have how much difference in DNA sequence?
0.1%
The phase of cell cycle associated with replication of DNA is
interphase
fractionation of cell organlles shows that
each organelle is responsible for specific cell activities, there is some degree of autonomy in cells, and we can study each organelle individually outside the cell
what bonding statement is incorrect?
peptide bonds hold nucleic acids together
denaturation of proteins results in
breakdown of the teriary structure
what statement about protein is correct?
peptide bonds are resonsible for teh primary structure, H-bonds for the secondary structure, ionic bonds for the tertiary structure, and sulfhydryl bonds for tertiary structure
all of the following are present in DNA except
sulfur
what kind of chemical bonds are found between paried bases of the DNA double helix?
hydrogen
all of the following statements apply to the watson and crick model of DNA except:
the two strands of the helix are held together by covalent bonds
what statement about enzymes is incorrect?
enzymes can make a thermodynamically impossible reaction possible
what is Km in enzyme mediated reaction?
a measure of enzyme-substrate affinity, the lower the Km the higher the affinity and the concentration of substrate needed for reaching 1/2 Vmax
Mitochondria is absent in what cells?
E.coli
What statement about cell culture is correct?
plant cell culture medium is the simplest
what organism is not most commonly used in molecular biology research?
earthworm
in evolution of life on earth what is the correct order of emergence?
bacteria, protista, plant, animal
enzymes work in the presence of vitamins and minerals because
coenzymes are vitamins which enhance enzyme-mediated reactions, and vitamins and minerals help the enzyme to become active
what technique is used to fractionate cellular organelles?
gradient centrugutins
which of the following is found in bacterial cells?
ribosome
One of the most important parts of meiosis?
recombinations
what is the nature of DNA replication?
semi-conservative
how was the semi-conservative nature of DNA replication discovered?
N15 labelling and centrifuging (3 bands)
what bases are needed for replication?
ATP, GTP, CTP, and TTP
why does replication need triphosphates?
the energy they release when broken down allows the reaction to proceed (3.5 vs. 7.5 bond energy)
Where does replication start?
at the replication orgin which is ~1000 nucleotides long all A-T
Eukaryotic vs. Prokaryotic orgins of replication
prokaryotes have only one, but eukaryotes may have up to 10,000
why is the replication origin all A-T?
A-T bonds have only 2 hydrogen bonds as opposed to G-C's 3. so its easier to break there
Where does DNA synthesis occur?
at the replication fork
What do you need for DNA to start synthesizing?
a primer (a short legnth RNA)
primer + helicase =?
primosome
DNA polymerase works in what direction?
5' to 3'
What quality is the replication fork?
assymetric because of leading and lagging strand
How accurate is DNA polymerase?
its only makes 1 in 10^7 mistakes
DNA polymerase has 2 sites for what functions?
DNA synthesis and proof-reading
proofreading is in what direction?
3' to 5'
what is nuclease's function?
to remove the primers off the lagging strands so they cna be joined by ligase
what mutation does sicle cell anemia involve?
a single nucleotide change from A to T
Kornberg could make ___, but not ___
synthetic and biologically active DNA and viruses, but not DNA polymerase
To finish replication these must be replicated
telomeres
What makes the end parts of DNA?
telomerase (an RNA polymerase)
Telomerase is what type of enzyme?
a synthesizing enzyme, it doesnt break anything
How many cell divisions in a cell life?
80-100
DNA polymerase is what quality?
self-replicating (because it makes the gene for itself)
Damage to DNA can happen by what?
chemical and physical agents (ex. electromagnetic radiation)
There is a low chance of getting cancer at a young age because?
the immune system is better at recognizing foreign cells and DNA polymerase is better
DNA repair involes 3 steps
excision, resynthesis, and ligation
transposable elements are also called
jumping genes
A large fraction of the human genome is made of?
2 families of transposable elements
Transposable elements can be identified by?
the teriminal inverted repeats next to flanking direct repeats
Jumping genes are responsible for?
verigated kernels and chromosome rearragements (like inversion)
transposable elements need?
DNA polymerase
Two types of transpositions?
cut and paste and copy and paste
Bacterial transpsans move by?
cut and paste
Retrotransposons are unique to?
eukaryotes
retrotransposons function to?
make RNA copies of transposable elements using RNA polymerase and reverse transcriptase
Two enzymes that help to unwind?
helicase and gyrase
How viruses vary?
they can be DNA or RNA, and there are plant, bacterial, and animal viruses
Viruses that attack bacteria are called?
bacteriophages
Viruses only attack their specific cell because of?
their protein coat
What is the Molecular Conspiracy?
the viruses genetic material make an infected cell replicate the virus DNA (~50 viruses) until the cell explodes
Two processes going on inside a viruses host cell?
Replication making more virus DNA and transciption--> translation that makes protein coat
Viruses can mutate frequenty because
they do not have repair machanisms
How many genes in E.coli, yeast, and humans?
4000, 15000, and 30000
What percentage of genes are continually functioning?
10%
Transciption needs?
RNA polymerase (does not need a primer)
4 types of RNA?
mRNA (gene copy), tRNA (for transfer), rRNA (plus a protein gives a robozome), and snRNA (is a ribozyme)
What is the difference between ribose and deoxyribose?
ribose has an OH where deoxyribose has an H
What is the difference between uracil and thymine?
Uracil has an H where thymine has a CH3
What at the beginning and end of a gene in DNA?
a promoter and a terminator
What initiates transciption?
the sigma factor binding to the promotor
In which direction does transciption move?
5' to 3'
About how long does it take to transcibe one gene?
50 seconds
What must RNA have to make it more stable?
a cap and a tail
What is the max life span of RNA?
up to 1/2 hour
DIfference between eukaryotic mRNA and prokaryotic?
Prokaryotic can transcibe several genes at once
What does the cap and tail of mRNA look like?
The cap is 3 phosphates, a G, and CH3. A tail is 5 As
What process is used to cut out introns?
splicing
What is a splicesome?
a combination of snRNA and proteins that make a complex called a SnRNP (involved in splicing)
What is the age range of mRNA?
3 minutes to 10 hours (average is 30 minutes)
Where does transciption and translation occur?
Transciption is inside the nuclues, translation is outisde on a ribosome (in eukaryotes)
What is making the tail of mRNA called?
polyadenylation
What do types 1, 2, and 3 RNA polymerase make?
1-rRNA, 2-mRNA, 3-tRNA
Who cracked the genetic code of translation?
Nirenburg
Which two amino acids are only coded for by one codom]n?
Met and Trp
There are 64 codon combinations, but only 20 amino acids which displays the quality of?
redundancy
The sigma factors purpose is to allow
the RNA polymerase to stick to the DNA
Some genes can be spliced in different ways to make different mRNAs, like...
alpha-tropomyosin
What is the initiation codon and the terminator codons?
initiation-AUG (Met)
terminator-UAA, UAG, UGA
The fact that some amino acids are coded for by several codons displays what quality?
degeneracy
How many tRNA's are there?
30 in prokaryotes, 50 in eukaryotes. tRNAs are iso-accepting
What is the reading frame set by?
the initiator codon
In order to attach to a ribosome mRNA needs?
a Shine-Delgarno box
tRNA consists of?
3' end, T loop, D loop, and the anticodon loop
Where are ribosomes assembled?
within the nucleolus of the nucleus
How big are the large and small subunits in eukaryotic vs. prokaryotic DNA?
eukaryotic-40s and 60s
prokaryotic-30s and 50s
What does the s stand for in mesauring ribosome subunits?
svedberg unit (involves the density in a centrifuge)
What are ribosomes made of?
rRNA and proteins
How many rRNAs and proteins in the large and small subunits of ribosomes in eukaryotes?
large-3 rRNA, 49 proteins
small-1 rRNA, 33 proteins
How do the ribosome parts fit together?
no chemical bonds, just sit together
What does the initiation of translation in bacterial cells require?
several initiation factors and GTP
What are the 3 steps of translation?
initiation, elongation, termination
What are the three sites on the ribosome?
A, P, and E site
What does the termination codon do?
It attracts release factors that disassemble the ribosome
What are the two types of ribosomes?
Free ribosome (if protein is for inside of the cell) and membrane-bound ribosome (if protein will be used in the membrane or ouside of the cell)
How does a cell quickly degrade a protein?
It gets labelled with ubiquitin that attracts proteasomes to degrade (called polyubiquitination)
How do antibiotics work?
They interfere with the translation of prokaryotes
What is contact inhibition?
As soon as cells touch they stop replicating
What plays the most important role in limiting cell replication?
the telomere
When cells are diving what is it called before they specialize? And after?
Morula, then a Gastrula
Where do stem cells establish?
On the mesoderm
What will happen to genes without a purpose put into an organism through recombinant DNA technology?
it will eventually be lost throughout the generations
What molecules are needed for PCR?
DNA polymerase and nucleotides
What bacteria are used to prevent DNA polymerase from denaturing?
thermophilic bacteria (Taq)
What is the technique of transfering gel information to nitrocellulose paper?
Southern Blotting
What blotting technique is used for RNA? For proteins?
RNA-Northern Blotting
Proteins-Western Blotting
What are small DNA Probes made of and what is their purpose?
They are made of radioactive nucleotides and are used to locate specific DNA on a blot
What is autoradiography?
When probes made DNA visible on a blot next to XRay film
What is the hardest part of molecular biology?
Figuring out the sequence of genes
What molecules are involved in the Sanger Sequencing Method?
dideoxyribonucleosides (missing an OH)
RFLP = ?
Restriction Fragment Length Polymorphism
If you used a restriction enzyme on the human genome how many pieces would you get?
about 6 billion
What is a hypervariable microsatellite?
a small part of DNA that can be used to tell people apart (used in forensics)
What is a genomic library comprised of?
Millions of recombinant DNA molecules in plasmids inserted into bacteria
How is a cDNA library made?
derived from mRNA using reverse transcriptase (so it has only exons)
Denaturation of DNA can be done at what temperatures and pHs?
100 degrees and 10-11 pH
What is in situ Hybridization?
Make naked DNA by removing the histones, denature the DNA, add the gene with a probe and see where it binds
What do hemophilliac patients lack?
Protein VIII (Factor F Protein)
What is an expression vector?
A plasmid carrying gene that is expressed by the bacteria
What is a cloning vector?
A plasmid carrying gene that is replicated by the bacteria
What is the only way to make a transgenic animal?
Introduce the genes into the gametes
What time period did we learn a lot about the cell membrane?
1960s-1970s
What are all membranes made of?
Phospholipids and proteins (different types and percentages)
What is the most complex and important part of the cell?
cell membrane
What does the membranes structure allow it to do?
Sense the physical environment
How wide is the phospholipid bilayer?
5 nm
What is the head and the tail of a phospholipd made of?
Head-glycerol and phosphoric acid
Tail-fatty acid
What does amphipathetic mean?
One side if hydrophillic and the other hydrophobic
What is a two-layered circle of phospholipids called?
A liposome
Where are membranes made?
Smooth ER
What are membranes made for?
cell expansion, repair, new organelles
What organelle specializes membranes?
golgi
What correctly positions proteins in the membrane?
Flippase enzyme
What are carbohydrates attached to peripheral proteins called?
antenna molecules (or gycoproteins)
the most common phospholipid has?
choline
How is the fluidity of the membrane increased?
More unsaturated fatty acid tails (like in animals in cold regions)
What molecule keeps the membrane stable?
cholesterol
What quality is the membrane?
assymetric
What are the 4 functions of proteins in the membrane?
transporters, anchors, receptors, and enzymes
What is the hydrate layer?
The coating of carbohydrates on the cell surface that serve as recognition molecules
What does the cell fusion experiment show?
Protein lateral mobility in the membrane
What is the phospholipid bilayer permeable to?
small, hydrophobic molecules (such as O2, CO2, N2, H2O, gycerol, and ethanol)
Which part of the membrane causes it to be semi-permeable?
the hydrophobic tails
How can water pass so quickly through the membrane?
aquaporins
Suction of Water =
Osmotic Pressure - Wall pressure
How do protista get water out of the cell?
Vacuoles pump water out
What are teh 3 types of passive transport?
simple passive transport, carrier mediated, and channel mediated
In animals about how much of the bodies energy is used for basal metabolism? And how much for active transport?
basal metabolism-2/3
active transport-1/3
How much oxygen is used for humans brain?
1/5
How do channel and carrier mediated proteins specify between molecules?
shape and size
What are the 3 types of active transport?
coupled, ATP-drived, and light driven
What does semi-permeable mean?
its only permeable to water
What does osmotic pressure depends on?
molarity
In dilute solutions what can affect osmotic pressure in addition to molarity?
number of ions
What are the three types of proteins for glucose diffusion in red blood cells?
G1, G2, G3
What are the three types of gates on channel gated proteins?
voltage gated, ligand gated, and mechanically gated
What do plant, fungi, and bacteria have instead of a Na-K pump?
H+ pump
What are the two driving forces in passive transport?
concentration gradeint and electrochemical gradient
What cells can do pinocytosis and phagocytosis?
only specialized cells in animals