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