Biology Chapter 5: Gene Expression, Biotechnology, and Laboratory Techniques Flashcards
Necrosis vs apoptosis
Necrosis: premature death of living cells by autolysis
Apoptosis: naturally occurring, programmed, and targeted cause of cellular death.
Vector
is a carrier used to deliver genetic material, such as DNA or RNA, into cells for research or therapeutic purposes.
Reporter Gene
gene used in molecular biology to produce a measurable product, such as fluorescence or enzymatic activity, to indicate the expression of a target gene or the activity of a regulatory sequence.
common reporter in bacteria is the E. coli lacZ gene, which encodes the protein beta-galactosidase. This enzyme causes bacteria expressing the gene to appear blue when grown on a medium that contains the substrate analog X-gal.
Restriction enzymes
protein that recognizes specific DNA sequences and cuts the DNA at or near these sites, commonly used in molecular biology for DNA manipulation.
Totipotent stem cells
Can differentiate into any type of cell
Pluripotent stem cells
are stem cells that have the ability to differentiate into any cell type in the body, except for extraembryonic tissues (e.g., placenta).
Multipotent stem cells
Most limited range
Only embryonic stem cells are ________. Mature stem cells are _________
Totipotent/pluripotent, multipotent
Histone acetylation _____________ transcription
Increases
DNA methylation _____________ transcription
Decreases
siRNA and miRNA _______________ protein synthesis
Decrease
Oncogenes
are mutated or overexpressed genes that drive uncontrolled cell growth and division, contributing to the development of cancer
Tumor suppressor genes
are genes that regulate cell growth, repair DNA damage, and prevent uncontrolled cell division, acting as a safeguard against cancer. When these genes are mutated or inactivated, cells can grow uncontrollably, leading to tumor formation.
Example of tumor suppressor gene
TP53 Encodes the p53 protein, which halts the cell cycle in response to DNA damage and can trigger apoptosis (programmed cell death).
Mutations in TP53 are common in many types of cancer
Tumorigenic phenotype
refers to the set of cellular traits or behaviors, such as uncontrolled growth, resistance to cell death, and invasiveness, that enable the formation and progression of tumors.
post-transcriptional modifications occur in the
nucleus
Steps in blotting
1) Run fragments through gel electrophoresis (size)
2) Transferring sample from gel via blotting (Pasting paper on top)
3) Using a labeled antibody to detect a specific molecule
Which blotting technique can provide info on transcription?
Northern blot (RNA)
Which blotting technique can provide info on translation?
Western blot (protein)
DNA palindrome
means that the sequence is the same on both strands when read in the 5’ to 3’ direction. ie AAGCTT
Restriction enzymes typically recognize and cut
palindromic sequences in DNA (usually 4 - 8 base pairs long)
HindIII
is a type II restriction enzyme that recognizes the specific palindromic DNA sequence 5’-AAGCTT-3’ and cuts at a specific site within that sequence.
Transfected
refers to the process of introducing foreign genetic material (DNA or RNA) into a eukaryotic cell using non-viral methods.
transfection occurs only by artificial means and is carried out in a lab.
Isoforms
different versions of a protein that come from the same gene but have different exon combinations due to alternative splicing.
Alternative splicing
a cellular process in which exons from the same gene are joined in different combinations, leading to different, but related, mRNA transcripts. These mRNAs can be translated to produce different proteins with distinct structures and functions — all from a single gene.
DNA probe
are single-stranded sequences of DNA or RNA used to search for its complementary sequence in a sample genome. Researchers use DNA probes to screen the genome, looking for the identification of cancers or hereditary syndromes. The probes are also used to identify microorganisms.
Open Reading Frame (ORF)
is a continuous sequence of codons in mRNA that begins with a start codon (AUG) and ends with a stop codon (UAA, UAG, or UGA). It represents the protein-coding region of the mRNA.
frameshift mutation
Frameshift mutations often alter the codon in which they were introduced, along with downstream codons. This will retain the same amino acid sequence from the amino terminus up to the point of the mutation. By contrast, the amino acid sequence from the point of the mutation through the carboxy-terminus will be altered, although the stop codon is maintained.
Types of point mutations
silent mutation vs conservative missense mutation
Silent mutations do not change the amino acid.
Conservative missense mutations do change the amino acid, but the new one is functionally similar.
What is 5’-UTR
5’-Untranslated Region
It is part of the mRNA but does not code for amino acids.
It is located upstream of the start codon (AUG).
It plays a role in regulating translation, mRNA stability, and ribosome binding.
5’-UTR vs coding region vs 3’-UTR
Why Does One Primer Lead to Linear Amplification in PCR?
PCR requires two primers (forward and reverse) to enable exponential DNA replication.
If only one primer is used:
It binds to only one of the two DNA strands.
Each cycle produces only one new strand (complementary to the original).
This new strand cannot serve as a template for further amplification since there is no second primer to bind to it.
As a result, only one strand is linearly amplified.
Thus, with one primer, amplification is linear because each cycle only adds one additional copy, instead of doubling the number of DNA molecules.
What kind of amplification occurs for single and double primers?
1 primer → Linear amplification (inefficient, one new strand per cycle).
2 primers → Exponential amplification (each cycle doubles the DNA amount).
mature mRNA consists of what parts?
consists of a 5’-cap (one base pair), the 5’ UTR, coding regions, the 3’ UTR, and a poly(A) tail.
Most compact to least compact?
1) Euchromatin
2) Heterochromatin
3) DNA
1) Heterochromatin (most compact)
2) Euchromatin
3) DNA
