RNA, DNA, & Cells Flashcards
RNA performs these essential functions:
-converts genetic code from DNA to proteins
-regulates the process of gene expression
-facilitates biological reactions
-senses/communicates responses to cellular signals
-exist as the genetic material found in some viruses
During transcription, carries information transcribed from DNA to the cytoplasm of the cell
mRNA (messenger RNA)
During translation, gathers the appropriate amino acids and delivers them to the ribosome.
tRNA (transfer RNA)
During translation, carries out protein synthesis in the ribosome.
rRNA (ribosomal RNA)
Involved in splicing and processing of mRNA in the nucleus.
Contributes to transcription by modifying newly made mRNA.
Small Nuclear RNA (snRNA)
The joining or connecting of different segments of DNA or RNA.
Splicing
RNA present in the cytoplasm.
Small Cytoplasmic RNA (scRNA)
Small, highly-conserved segments of non-coding RNA that are involved in regulation of gene expression.
Micro RNA (miRNA)
RNA used in laboratories.
Regulates gene expression through RNA interference.
Small Interfering RNA (siRNA)
Silences genes by specifically targeting and degrading their RNA.
RNA Interference (RNAi)
Special type of virus that uses RNA (not DNA) as its genetic material.
Retrovirus
Changes in DNA.
Mutations
At the beginning of an mRNA sequence instructs to ribosome to begin fabricating a chain of amino acids.
Start Codon
Tell the ribosome to stop adding amino acids to the poly peptide chain.
Stop Codon
Happen during meiosis due to damaging agents (such as radiation or exposure to teratogens during development phases).
Large-Scale Mutations
Large-Scale Mutation
A segment of DNA is lost.
Deletion
Large-Scale Mutation
A segment is duplicated and inserted back into the original DNA.
Duplication
Types of large-scale mutations:
Deletion
Duplication
Inversion
Translocation
Large-Scale Mutation
A segment of DNA is reversed.
Inversion
Large-Scale Mutation
A segment of DNA is moved to another homologous chromosome.
Translocation
Primary affect protein synthesis.
Important source of diversity among organisms because they’re the source of new genes.
Classified as single nucleotide pair substitutions and nucleotide pair insertions or deletions.
Can have little to no impact (base pair substitution) OR can completely disrupt the reading frame (deletion) causing serious consequences.
Small-Scale Mutations
Occur at a single nucleotide.
A single nucleotide changed to another nucleotide.
Point Mutations
Point Mutation
Even though a base pair has been changed, the codon still codes for the same amino acid.
Silent Mutation
Point Mutation
The change in a single base changes the amino acid inserted.
Missense Mutation
Point Mutation
A single base-pair substitution that ends translation early.
If a sequence inadvertently codes for a stop codon, then translation can end too soon, and the protein is generally nonfunctional.
Nonsense Mutation
Point Mutation
A deletion or insertion of DNA shifts the reading frame of the mRNA message.
Disrupt the reading frame and can completely change the polypeptide that’s synthesized.
Frameshift Mutation
Change the DNA sequence of the gene.
Mutation
Hereditary mutations.
Inherited from a parent.
They’re in germ sells (parents’ sperm/egg cells).
Germaine Mutations
Acquired mutations.
Occur at some point in an organism’s life (not inherited from parents).
Caused by environmental exposure to mutagens.
Found in somatic cells and can’t be passed on to future generations.
Somatic Mutation
Any agent that cause genetic mutations (ex. UV-light, radioactive compounds, X-rays, some chemicals).
Mutagens
Genetic changes that occur in more than 1% of the population.
Genetic Polymorphisms
Steps in cell development:
1 - Cell Proliferation
2 - Cell Differentiation (& Specialization)
3 - Cell-Cell Interactions
4 - Cell Movement
Groups of cells that together have specific functions.
Tissues
The process of growth and division of cells that produce many cells from the original cell.
Divide through mitosis. —> Producing 2 identical cells (way cells pass on their genetic information across generations.
End goal = To create exact copes of a given cell and ensure that there are enough different cells for each type of tissue.
Cell Proliferation
Must go through this process to develop features that enable them to fulfill specific roles.
Cell Differentiation
Specialized cells have different genes turned on and expressed ad different times in the cell.
How different genes are turned on/off determines the ultimate fate of the cell.
Cell Specialization
Unspecialized cells that can divide limitlessly and differentiate into specialized cells.
Stem Cells
Can specialize in any of the cells the organism needs to grow and develop PLUS the extra embryonic cells necessary for the embryo to grow.
Zygote.
Totipotent
Can give rise to all of the body’s cell types, but NOT the extra embryonic cell types.
Embryonic stem cells.
Pluripotent
Can give rise to several different cell types, but their specialization is limited to the tissue in which they’re located so they can replace dead or damaged tissue.
Adult stem cells.
Multipotent
Adult cells that have been reprogrammed to become like embryonic stem cells.
Pluripotent so give rise to all the cells in the body.
Derived from adult stem cells so may still have DNA abnormalities that come from a lifetime of cell division.
Induced Pluripotent Stem Cells (iPSCs)
Types of cell-cell interaction (signaling):
Direct Contact
Paracrine (and Synaptic)
Autocrine
Endocrine
Cell-cell interaction (signaling)
Cells are located next to each other and small channels between the cells allow small molecules to diffuse from one cell to another.
Direct Contact Interaction
Cell-cell interaction (signaling)
Involves the production of a chemical signal by a cell… The chemical then diffuses over a short distance to reach nearby cells.
Paracrine Signaling
Cell-cell interaction (signaling)
Paracrine signaling in the nervous system.
Occurs between cells separated by a synapse (gap) over which neurotransmitters can diffuse to send messages from one cell to another.
Synaptic Signaling
Cell-cell interaction (signaling)
Involves a cell signaling itself. —> Cell releases molecules that bind to receptors on its surface.
Autocrine Signaling
Cell-cell interaction (signaling)
Signaling conducted by hormones, which can travel throughout the body via the circulatory system.
ex. Insulin made by the pancreas regulates blood sugar levels throughout the body.
Endocrine Signaling
