Biol 1103
Primary Source
first hand accounts by researchers and professionals (theses, dissertations, scholarly journals)
Secondary Source
analysis or restatement of primary sources (magazines, newspapers, articles, textbooks)
Tertiary Source
sources that index, organize, or compile other sources (Wikipedia, fact books, guidebooks)
What is a Crap Test used for
to evaluate the quality of a source of information
What does Crap test stand for?
Currency, Relevance/Reliability, Authority/Audience, Purpose/Point of view
Epigenome
is what tells the DNA what to do based on chemical compounds and changes due to environmental factors
How does epigenome affect your cells?
by adding or taking away methyl groups or acetal groups, determining which genes are going to be expressed or not
Epigenome Study?
Study of heritable phenotype changes that do not involve changes in the DNA sequence
Why are all the cells in an individual genetically identical yet have distinct functions and characteristics?
Every cell in your body contains all genes, however only some of them are on or expressed, giving the tissue unique functions
Describe the protein involved in winding DNA into chromatin.
DNA is wound around histones, depending on how loose or tightly the histones are wrapped depends on whether or not the gene will be expressed
How does chromatin structure or chemical modification of DNA - known as epigenetics - affect gene expression?
by adding or taking away methyl or acetal groups, changing how tightly histones are wrapped, thus effecting how they are expressed. (tight = off, loose = on)
Methylation
causes histones to be wrapped tighter, turning off those genes
Acetylation
causes histones to be loosely bound and expressed in DNA
When does "epigenetic regulation" normally occur?
happens by proteins binding to the specific DNA sequence either activating transcription or shutting it down
Why does "epigenetic regulation" occur?
genes regulatory proteins recruit enzymes to add or remove these epigenetic tags
example of how epigenetic changes can occur in response to the environment
The chemicals in DNA can be altered by the foods people eat by changing the physical structure of the DNA or adding methyl or acetal groups
What are Regulatory Proteins?
proteins that attach themselves to a specific DNA sequence of one or more genes - it can block RNA polymerase from binding
Role of Regulatory Proteins in adding tags to the epigenome.
it can block RNA polymerase from binding
Explain how changes to the epigenome can be responsible for cancer
if certain genes are turned on or off, cells may rapidly divide for no reason
What happens when Methylating genes regulate cell division?
prevents those genes from doing their job and can cause rapid growth
What happens when Acetylating genes are responsible for cell division?
can cause unnecessary amounts of cell division, also causing rapid growth
How do chemotherapy drugs take advantage of methylation to re-activate gene expression
reverse the effects of the over-methylated or over-acetylated genes that are causing the rapid cell division by introducing either methyl groups or acetal groups depending on the type of cancer
How are Microarrays produced and used to detect differences in gene expression between cells?
Take normal and cancerous tissue samples; Remove the RNA; Dye the RNA; Add it to the microarray and rinse; Compare the different colors for the different genes and how they differ based on healthy and cancerous cells
If given a microarray, be able to explain what color spots you would expect to see for genes that are expressed in normal cells or overexpressed or under-expressed in cancer cells.
Green = mostly healthy; Red = mostly cancerous; Yellow = roughly same amount of both
The basis of cellular differentiation (e.g. kidney cells functioning and appearing different than nerve cells) is:
selective gene expression
Most differentiated cells (i.e. cells that develop into specific types such as nerve or muscle cells) retain:
a complete set of their genes, an retain the ability to express those genes under certain circumstances
Only cells in the digestive system have genes for digestive enzymes
False
Genes can be switched on and off in each particular cell type.
True
Brain cells and liver cells are genetically identical
True
Portions of DNA that have few methyl tags will be loosely wound around histones and can be transcribed.
True
In our cells, gene expression can be controlled by numerous mechanisms beyond transcription factors or epigenetic tags.
True
What is the relationship between DNA and proteins?
DNA encodes for proteins, and protein enzymes replicate and maintain DNA.
The term "gene expression" refers to the:
process by which genetic information flows from genes to proteins.
The GR gene, which codes for a protein that results in anxious behavior in rats, can be activated by:
injecting a drug that removes methyl groups from the DNA for the GR gene.
If you were able to look very closely at a portion of DNA and find methylated histones (histones with methyl groups), you would
observe highly compact chromatin structure
All of the following are true about DNA methylation, EXCEPT: take place on the DNA, enzymes add a methyl group, when it occurs, transcription is more likely to occur, chromatin becomes more tightly packed
when it occurs, transcription is more likely to occur
A densely staining region of highly compacted chromatin is known as _____Incorrect Response and is generally transcriptionally ______Incorrect Response
heterochromatin / inactive
During the process of cell division, epigenetic tags such as methyl groups are removed from DNA molecule.
false
DNA methylation leads to genomic imprinting, which is reversible
True
DNA methylation: it can silence genes on entire chromosomes, it, is a method of translational regulation, it is common in prokaryotes
False
Transcription ON
chromatin loosely wound (euchromatin),
acetylated histones
Transcription OFF
methylated DNA
chromatin tightly wound (heterochromatin)
methylated histones
Of these nucleotides ATCG, which pairs most closely resemble each other in size and shape?
T most closely resembles C
and
A most closely resembles G
the double helix of DNA, the "teeth holding together the two strands of the double helix consist of
hydrogen bonded nitrogen-containing bases
Identify the correct order of organization of genetic material, from largest to smallest.
Genome, chromosome, gene, nucleotide
Which of the following has a beads on a string structure?
nucleosomes
Inheritance of traits by mechanisms not directly involving nucleotide sequence is called
Epigenetic inheritance
If a cell were unable to produce histone proteins, which of the following would be expected to occur?
The cell's DNA could not be packed into its nucleus.
Which of the following is the main difference between a primary and secondary source?
Primary sources describe a single research study about a phenomenon or question, secondary sources present several research studies about that same phenomenon
Epigenetics describes the effect of on gene expression.
parental care
diet
environment
Studies examining epigenetic tags in twins have been useful in identifying variation in gene expression in humans. Which of the following patterns would you expect to be true based on epigenetics.
Younger identical twins have more similar epigenetic tags on their DNA because they have a more common life experiences.
If you were able to look very closely at a portion of DNA and find methylated histones (histones with methyl groups), you would:
be looking at a region of inactive DNA
The GR gene, which codes for a protein that results in anxious behavior in rats, can be inactivated by:
Injecting a drug that results in tightly winding the section of DNA that contains the GR gene.
The number of genes on each chromosome is different in different cell types.
False