Cell and Molec.
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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