exam 2 sample q's Flashcards
transcription factor
protein that promotes transcription
chromatin
mixture of DNA and proteins that form the chromosomes
chromosome
long DNA molecule with part of all of the genetic material in an organism. Single stranded form of condensed chromatin
sister chromatid
duplictaed copes of a single chromsoome that are attached to each other and are identical
independent assortment
alleles of two or more differebt gametes assorted into gametes indednet of one another. this si why offspring siblings will look different from each other. when cells divide during meiosis, homologous chromsoomes are randomly distributed to daughter cells
exon
coding sections of RNA transcript or the DNA encoding it, that are translated into a protein.
EXONS ARE PARTS OF A GENE THAT CODE FOR A PROTEIN
introns
nucelotide sequences in DNA adn RNA that do not code dreicly fot a protein
anabolic pathway
metabolic pathway that consues energy from synthesis of large molecules from smaller ones
catabolic pathway
metabolic pathway that releases energy from breaking down larger molecules into smaller ones
List and define the metabolic modes observed in prokaryotes?
The modes present in prokaryotes are phoottrophs and chemotrophs. Phototrophs obtain energy from the sun and chemotrophs obtain energy from chemicals.
List and define the metabolic modes observed in eukaryotes?
The modes found in euaryotes are photoautotrophs and chemoheterotrophs. Photoautotrophs carbon source is CO2 or related compounds and energy is obtained from the sun. Chemohererotropsh obtain energy from obtain energy from organic molecules and their carbon source is also organic molecules.
What is the endosymbiont theory? What evidence supports the endosymbiont theory
The endosymbiont theory is the theory that mitochondria and plastids orginated as prokaryotic cells engulfed by a host cell. The engulfed cell and its host then evolved into single organisms. The evidence that supports it is: 1)mitochondria and chloroplasts have their own DNA, ribosomes and double membranes. 2)mitochondria and chloroplasts replicate by binary fission. 3)DNA similar to prokaryotes that had similar functions
interphase
the phase tat is preparing the cell for division (mitosis). During interphase chromsoomes are duplicated. it consist of G1 which is metabplic growth and activity and S phase- it consist of metabolic growth and activity and DNA synthesisi. S phase is the part of interphase when chrosmomes are duplicated. G2 phase is metabolic growth and activity and its fully preparing the cell for dvisiion
mitosis
the cell division. It results in diploid daughter cells which means that the two daughter cells are identical to each other and the parent cell
subphases of mitosis
-prophase
-prometaphase
-metaphase
-anaphase
-telophase
-cytokinesis
prophase
when the chromsomoes condense and the microtubules/spindles attach to each chromosome
prometaphase
when the chromsomes further condense
metaphase
when the chromsomes line up in the middle of the cell
anaphase
when each chromatid is pulled aprt to opposite ends of the cell
telophase
when te ncueli form on each side of the cell
cytokinesis
final step- division of the cytoplasm
What is crossing over? When does it occur? What does it result in
It is the exchange of genetic material between homologous chromosomes during phrophase I of meiosis result in a mix of parental characteristics in offspring.
What is the composition (protein, mRNA, DNA) of the following components? Repressor, Transcription Factor, Operator, Promoter, Transcript, RNA polymerase, Ribosome, control elements
A repressor is a protein that inhibits transcription. A transcription factor is a protein that regulates the transcription of genes. Operator is DNA. Rrepressor molecule can bind to the operon and block RNA polymerase. Transcript is mRNA. RNA polyermase is a protein that aids in transcription. Ribosome is DNA, it synthesizes proteins. Control elements is DNA.It is elements of non coding DNA that serves as binding sites for transcription factors.
Why is gene regulation important in prokaryotes? Unicellular eukaryotes? Multicellular eukaryotes?
Gene regulation is actually important in unicellular eukaryotes because to help with the response to cellular and environmental cues. Gene regulation is important in multi-cellular eukaryotes in compartmentalization. Compartmentalization in cells is the separation of the cell interior in distinct sections with specific local conditions that allow the simultaneous occurrence of diverse metabolic reactions and processes. In multicellular eukaryotes, gene regulation also helps with the response to environmental cues as well.
If bacteria are grown in medium without tryptophan present, what is the condition of the trp operon? If these bacteria are transferred to medium with tryptophan, what is the response of the trp operon?
If tryptophan is not present in the environment the bacterium needs tryptophan for synthesis of proetins. Then, if trp becomes present in the envornments the bacterium does not need tryptophan for protein sytnethsis. Representing trp operson saves energy required to synthesize the enzymes of the pathway to make trp.
Explain why an anabolic pathway in prokaryotes is likely to be regulated by a repressible operon, but a catabolic pathway is regulated by an inducible operon.
Repressible operon represses transcription and an inducer blcoks the repressor and promotes transcription. With anabolic pathway, repressing the gene involved in biosynthesis when the end of the product is plentiful saves energy. With catabolic pathways inducing the genes involved in breaking down particular molecule only when that molecule is present saves energy.
what is the difference between a repressible operon and inducible operon
repressible operon represses trancription and an inducible operon bloclks the repressor and promotes trancription
Describe mRNA processing in a eukaryote. How is mRNA different in prokaryotes?
In eukaryotes transcription produces pre-mRNA molecule that can be processed into mature mRNA by the addition of a 5’ cap and a 3’ tail. mRNA in prokaryotes posses exons but does not have introns, while eukaryotic mRNA do have introns and exons.
Compare these different forms of cell division- binary fission, mitosis, meiosis. Identify common features, major differences, and which cells perform each type of cell division.
Binary fission is when a single cell called the parent cell splits into two cells called daughter cells. Mitosis Is when two daughter cells are made from division that are identical to each other and the parent cell. It is diploid, two identical sets to each other and they are somatic. Meiosis is haploid. It is a process where a single cell divides twice to produce four cells containi g half the original amount of genetic information.
What is the difference between euchromatin and heterochromatin? What process converts chromatin from one form to the other and how are these forms related to regulation of gene expression?
euchromaitn is loosely packed chromsoomes. heterochromatin is tightly packed chromsomes and the genes are ot usually expressed. the process that converts them from one form to another is chromatin modification
-remember DNA methylation
Distinguish between determination and differentiation during embryonic development.
Differntiation no precedes determination. Differentation is the process by which cells become specialized in structure and function. Determination is the process by which cells become specialized I structure and function. Determination also irreversibiky commits a cell to becoming a particular cell type.
what is the function of homeotic genes?
they are the regulator gene that directs the development of particular body segments or structures
Describe the role of cytoplasmic determinants in the induction of embryonic cells to undergo differentiation.
Cytoplasmic determinants come from the mother. They are maternal substances such as protein or mRNA, that when placed into an egg influences the course of early development by regulating expression of genes that affect developmental fate of cells. Induction is cells from one area of the embryo influence another via signals that affect gene expression.
