Module 1 bio 203
Ectoderm
(external layer) Skin, Neurons, eyes, ears
Endoderm
(internal layer) Pancreas, Liver, Thyroid, Lung
Mesoderm
(middle layer) Bone marrow, muscle, blood vessels
Chromatin is:
A complex of DNA and proteins that makes up chromosomes
People predisposed to colorectal cancer are usually born with a mutation in copy of this gene:
APC
Tumor
Abnormal proliferation of cells
The regulatory pathways disrupted in most human cancers are:
Cell proliferation Cell survival Cell growth DNA damage response
What maintains the hematopoietic stem cell?
Cell to cell contact
Events/conclusions from studies during the mid-1800s surrounding the discovery of the cells
Cells came to be known as the smallest universal building block of living organisms. Light microscopy was essential in demonstrating the commonalities between plants and animal tissues. New cells arise from the growth and division of previously existing cells.
Function of mRNA?
Code for proteins
Plasmodesmata (plant cell junction)
Communicating (cell/cell) functional classification.
A reason why gene expression is more complex in eukaryotes that it is in prokaryotes is:
Eukaryotic RNA must be processed
Chromosomal loop-forming clamp proteins:
Favor association of each gene with its proper enhancer
Function of rRNA?
Form the core of the ribosomes structure and catalyze protein synthesis
Gap junction
Forms channels that allow small, intracellular, water-soluble molecules, including inorganic ions and metabolites, to pass from cell to cell
Proteoglycans are...
GAGs linked to proteins Forms gels of varying pore sizes, regulate entry of molecules Binds growth factors and other signals Block, guide or encourage cell migration. Affect cell/tissue behavior
What statements about tumor suppressor genes are true?
Gene amplification of a tumor suppressor gene is less dangerous than gene amplification of a proto-oncogene. Inactivation of tumor suppressor genes leads to enhanced cell survival and proliferation. Individuals with only one functional copy of a tumor suppressor gene are more prone to cancer than individuals with two functional copies of a tumor suppressor gene.
Drosophila: Invertebrate model
Genetic model for human diseases
Microtubules
Hollow cylinder, 25 nm diameter Tubulin subunits Rigid, rupture when stretched Provide tracks for materials in cells Mitotic spindle - chromosome separation
Cytoskeletal Elements
Intermediate filaments, microtubules, and actin filaments(microfilaments)
Malignant
Invading capacity
A promoter:
Is a DNA sequence that initiates transcription Is recognized by the RNA polymerase and its accessory proteins
p53:
Is a tumor suppressor Is involved in stopping cells with DNA damage from going through the cell cycle
The Lac operon in bacteria:
Is regulated by both an activator and a repressor
Adherens junctions
Joins an actin bundle in one cell to a similar bundle in one all to a similar bundle in a neighboring cell
Desmosome
Joins the intermediate filaments in one cell to those in a neighbor
Which of the following is Not found in prokaryotes? A. Nucleus B. Ribosomes C. Microtubule D. DNA
Nucleus and microtubules
Arabidopis: Plant model
Physiology of crop plants, plant evolution
Cells of the inner cell mass are:
Pluripotent
Mitochondria
Powerhouse of the cell- makes most ATP- has its own DNA
Chloroplasts
Produces food - photosynthesis- has it's own DNA
When a terminally differentiated cell in an adult body dies, it can typically be replaced in the body by a stock of:
Proliferating precursor cells
What is a statement about animal connective tissues is TRUE?
Proteoglycans can resist compression in the extracellular matrix.
Cytoskeleton
Provides framework for the cell
Factors that can combine to regulate expression of an eukaryotic gene include:
RNA polymerase Mediator Chromatin remodeling complex
Function of miRNA?
Regulate gene expression
Benign
Remains confined to the original location
What is a statement about plant cell walls is TRUE?
The microtubule cytoskeleton directs the orientation in which cellulose is deposited in the cell wall.
Zebrafish [Danio rerio]
Transparent embryo
C.elegans: Invertebrate model
Transparent, 959 cells
True or false: Membrane components in the cell are made in the endoplasmic reticulum.
True
True or false: The Golgi apparatus is made up of a series of membrane-enclosed compartments through which materials destined for secretion must pass
True
Function of noncoding RNAs?
Used in RNA splicing, gene regulation, telomere maintenance, and many other processes
What are proto-oncogenes?
a dominant mutation for gain of function
Collagen is
a glycoprotein
A transcriptional regulator that can trigger the formation of an entire organ is called:
a master transcriptional activator
What are tumor suppressor genes?
a recessive mutation for loss of function
Peroxisomes
allows reactions to occur in the cell that would be damaging- uses hydrogen peroxide
Proteins are important architectural and catalytic components within the cell, helping to determine its chemistry, its shape, and its ability to respond to changes in the environment. Remarkably, all of the different proteins in a cell are made from the same 20 __________. By linking them in different sequences, the cell can make protein molecules with different conformations and surface chemistries, and therefore different functions.
amino acids
Micro RNAs are?
are expressed by a cellular gene as a longer precursor RNA molecule are dependent on complimentarity for specificity complex with RISC proteins
Zebrafish (Danio rerio) are especially useful in the study of early development because their embryos
are transparent
A hemidesmosome:
attaches a cell to the ECM
What are the matrix components of bone?
calcium phosphate, collagen
Totipotent
can form all cells in the embryo, placenta, and extra placental tissues
Pluripotent
can form all cells of the embryo but not placenta or extra embryonic structures
Cells that are terminally differentiated
can no longer undergo cell division.
What bEST describes the role of the lysosome?
clean-up, recycling, and disposal of macromolecules
Cytoplasm
contents of the cell inside the plasma membrane but outside the nucleus
Plasma membrane
creates the boundary for the cell
Lysosomes
digest old organelles/recycles
Where is cellulose synthesized?
extracellularly, outside the cell
Multipotent
form more than one cell type
Unipotent
form only one type of cell
The plasmodesmata in plants are functionally most similar to which animal cell junction?
gap junction
DNA:
has chemical polarity
Actin filaments (microfilaments):
helical filaments, 7 nm diameter actin subunits organized into linear bundles, 2D assemblies, and 3D gels with myosin, can contract
Nucleus
houses the genetic material (chromosomes
Frog [Xenopus laevis]
large oocyte - test tube
Endoplasmic Reticulum
lipid and protein synthesis- synthesizes materials for membrane and export
When complexed with a short single-stranded RNA, the RNA induced transcription complex (RITS):
recruits chromatin modifying proteins to generate heterochromatin at the transposon's locus
Intermediate filaments
rope-like fibers, 10 nm diameter various protein subunits (for example keratin) forms meshwork - can extend throughout cell flexible and great tensile strength
Tight junction
seals neighboring cells together in an epithelial sheet to prevent leakage of extracellular molecules between them; helps polarize cells
Mitochondria perform cellular respiration, a process that uses oxygen, generates carbon dioxide, and produces chemical energy for the cell. Which answer below indicates a correct pairing of the material "burned" and the form of energy produced during cellular respiration?
sugar, ATP
Genes transcribed from RNA polymerase III ?
tRNA genes, 5S rRNA gene, genes for many other small RNAs
Cytosol
the content of the cytoplasm outside the membrane bound organelles
Genes transcribed from RNA polymerase II ?
All protein-coding genes, miRNA genes, plus genes for other noncoding RNAs (e.g., those of the spliceosome)
Hemidesmosomes
Anchors intermediate filaments in a cell to the basal lamina
Nucleosomes:
Are responsible for "beads on a string" form of chromatin Contain histone proteins Contain ~200 bp of DNA
Where are embryonic stem cells found?
Blastocyst
E. coli: prokaryotic model
DNA replication, protein synthesis
Small interfering RNAs (sRNAs)
Could be processed from a viral ds RNA molecule Protect cells from viral infections Could be processed from an RNA that is an intermediate stage of a transposon Complex with RISC proteins
What must occur for a cell to differentiate?
Exit the cell cycle
Daughter cells "remembering" the gene expression patterns of the parental cell can occur due to:
Expression of a transcriptional regulator that is required for its own expression Inheritance of parental patterns of histone modifications Inheritance of parental DNA methylation patterns
True or false: Lysosomes are small organelles where fatty acid synthesis occurs
False, lysosomes breakdown and recycle cell components and some material entering the cell via endocytosis.
True or false: The number of mitochondria inside a cell remains constant over the life of the cell.
False, mitochondria number can change according to need
Yeast: Single cell eukaryote
Metabolic pathways, cell division
Golgi Apparatus
Modifies and packages molecules
Genes transcribed from RNA polymerase I?
Most rRNA genes
What was Louis Pasteur's contribution to cell biology/cell theory?
Negated the idea of spontaneous generation
Much of gene expression:
Occurs in euchromatin Occurs in regions of less chromosomal compaction
Fully differentiated Paneth cells:
Secrete Wnt and Differentiate from stem cells in the crypt
Function of tRNA?
Serve as adaptors between mRNA and amino acids during protein synthesis
Metastasis
Spread via the circulatory or lymphatic system
Chromosomes
Structures composed of proteins and DNA
Which of these cell juctions is funtionally a communicating junction?
plasmodesmata, gap junction
The artificial introductions of three key ______ into an adult cell can convert the adult cell into a cell with the properties of ES cells:
transcription factors