Cell Biology 315 Exam 1 Review

How does PCR work?

-Uses DNA polymerase to amplify selected DNA sequences in test tube -multiple cycles of amplication in vitro generate billions of copies desired nucleotide sequence - repeated rounds of strand separation,hybridization and synthesis to amplify the DNA

Even rare proteins can be made in large amounts using cloned DNA...

1. amplify the cDNA fragments using pcr 2.insert the cDNA fragment into an expression vector 3.introduce the engineered vector into the bacteria 4. Purify the target

how to identify a gene

1. computer identify ORF's 2. Identify genes through homology with genes from other organism 3.cDNA analysis, ESTS

comparing the eukaryotic transcription with the bacterial transcription, which statement is NOT TRUE? A. bacterial cells contain a single RNA polymerase wheras eukaryotic cells have three B. bacterial RNA polymerase can not initiate transcription without the help of many general transcription factors C. in eukaryotic cells, gene regulatory proteins can influence transcriptional initiation thousands of nucleotides away from the promoter whereas bacterial regulatory sequences are very close to the promoter D. eukaryotic transcription is affected by chromatin structure and nucleosomes whereas bacterial transcription is not

B. bacterial RNA polymerase can not initate transcription without the help of many general transcription factors.

The gene encoding RNA polymerase can be inactivated by a mutation in a cell. The cell attempts to replicate it's DNA. What will likely happen in the absence of DNA polymerase? A. no replication can take place at all. RNA primers will be laid down at the origin of replication B.The lagging DNA strand will consist of newly synthsized fragments with both DNA and RNA C. the rate of DNA replication will be greatly slowed down D. some new DNA will be synthesized

B.The lagging DNA strand will consist of newly synthsized fragments with both DNA and RNA

Describe the consequences that would arise if a eukaryotic chromosome lacked one or both telomeres A. the rate of DNA would severely limit the rate of cell division B. many mutations occur during DNA replication C. the chromosome ends would gradually shrink. Eventually, essential genes would be lost, leading to cell death D. Newly replicated chromosomes could not be partitioned accurately between two daughter cells.

C. gradually shrink (To prevent the loss of genes as chromosome ends wear down, the tips of eukaryotic chromosomes have specialized DNA "caps" called telomeres)

what kind of system would you want to use to study protein-protein interactions?

Examine protein interactions with affinity chromatography and immunoprecipitation

True or false: There is a great deal of diversity in histones from various eukaryotes

FALSE (Histones are the major protein constituents of the chromatin of eukaryotic cell nuclei. This group of basic proteins is extremely conserved throughout evolution and includes five classes termed H1, H2A, H2B, H3 and H4)

The differences between multicellular organisms are largely explained by the different kinds of genes carried on their chromosomes

False

How are the 2 strands of DNA double helix held together?

Hydrogen bonds between complementary base pairs

What is the origin of Mitochondria and Chloroplasts?

Mitochondria and chloroplasts likely evolved from engulfed prokaryotic that once lived as independent organisms; symbiosis

what are tRNA molecules?

Molecular adapters, linking amino acids with codons

What is the most damaging mutational change?

Removal of a single nucleotide in the beginning of coding sequence

which of the following mutational changes would you expect to be the most harmful to an organism? A. Insertion of a single nucleotide near the end of the coding sequence B. Removal of a single nucleotide in the beginning of a sequence C. Deletion of three consecutive nucleotides in the middle of the coding sequence D. substitution of the one nucleotide for another in the end of the coding sequence.

Removal of a single nucleotide in the beginning of the coding sequence

SEM vs TEM

SEM- scattered scanning electrons, 3D image of surface TEM- Transmitted Electrons - 2D projection image of inner structure

If you're running out of GTP, microtubules will...

SHRINK AND DISAPPEAR

The replication fork is asymmetrical because it contains two DNA polymerase molecules that are structurally distinct

True

True or False: Alternate splicing in RNA transcript can produce many diff proteins

True

True or False: Each Eukaryotic chromosome must contain following DNA Sequence elements: Multiple origins of replication, 2 telomeres and 1 centromere

True

True or False: Nucleic acid hybridization is used to isolate or identify specific DNA fragment by base pairing between complementary DNA or RNA probes and the DNA of interest

True

True or False: Regulatory DNA sequences and alternative splicing dictate each organism developmental program

True

How are base pairs in RNA slightly different?

Uracil in RNA - forms base pair with adenine U-A Thymine in DNA A-T

Mutations in specifc genes affect cell cycle organism that provides best model:

Yeast

The Genetic code is translated by what 2 adapters?

aminoacyl- tRNA synthesis and tRNA (anticodons)

affinity chromatography

can isolate the binding partners of protein of interest

smallest unit of life

cells

cDNA library

containing only codes

gDNA library

containing same random DNA sequences with repetitive sequences,introns,gene regulatory regions

what is cytosol?

cytosol is the rest of the cell excluding organelles and cell membrane ; concentrated aqueous gel

Main difference between cDNA library and gDNA library

gDNA library contains DNA fragments that express the whole genome cDNA- mRNA taken from specific cells of an organism, cDNA made from that mRNA in a reaction which is catalyzed by an enzyme

What are the structural differences between a plant cell and animal cell?

plant cell: cell wall, Plasmodesmata, chloroplast and vesicle

Electron Microscope

resolves fine structure of cell uses beam of electrons instead of beam of light, magnetic coil instead of glass

Second generation sequencing differs from Sanger Sequencing because

second generation sequencing can sequence tens of millions of pieces of DNA at the same time on a single glass slide

For each statement below which one is false A. All highly conserved stretches of DNA in the genome are transcribed into RNA B. To find functionally important regions of the genome, it is useful to compare species whose last common ancestor lived 100 million years ago rather than 5 million years ago C.Most important mutations and genome alterations have neutral consequences d. Proteins required for growth,metabolism, and cell division are more highly conserved than those involved in development and in response to the environment

A is FALSE, All highly conserved stretches of DNA in the genome are transcribed into RNA

When a mutation arises, it can have three possible consequences: A.beneficial to the individual B.Selectively neutral C.detrimental The spread of a mutation in subsequent generations will, of course, depend on its consequences to individuals that inherit it. Order the 3 possibilities above from that which is most likely to spread and become over-represented in subsequent generations to that which is most likely to become under-represent or disappear from the population

A,B,C Beneficial to individual, selectively neutral and detrimental

which of the following is NOT a type of mRNA modification/processing that occurs in eukaryotes: A. 3' poly A tail B.splicing C. Acetylation D. 5' capping

Acetylation

True or false: Covalent modification of protein such as phosphorylation ( the adding of a phosphate group to a protein) ubiquitination ( molecule ubiquitine added to protein) and acetylation may affect its location

TRUE

True or false: Sugar phosphate backbone of DNA double helix contains many negative charges and is hydrophilic

TRUE

small non-protein coding RNAs, such as microRNAs can regulate expression of protein-coding genes by controlling mRNA stability and transmission

TRUE! microRNAs direct the destruction of target of mRNAs

what is a limitation of PCR to detect and isolate genes?

the sequence at the beginning and end of the DNA to be amplified must be known

It is possible for a coding region of a gene to be present in a genomic library prepared from a particular tissue, but not to be represented in a cDNA library prepared from the same tissue

true

True or false: Difference in gene regulation may explain how animals with similar genomes are so different.

true