Quiz 1 Vocabulary Flashcards
Cell (plasma) membrane
The cell membrane consists of a lipid bilayer that is interspersed with proteins. Some of these proteins serve as receptors for hormones and can move within the membrane. The membrane forms the boundary of the cell and regulates the entry and exit of substances.
Centrosome
An important cytoskeleton organizer that is composed of two centrioles and helps with transport through the endoplasmic reticulum and Golgi apparatus. The centrioles separate at mitosis and aid in the formation of the mitotic spindle.
Chromatin
That part of the cell’s nuclear substance which forms the most conspicuous part of the nuclear network; it includes the chromosomes, and stains deeply with certain types of dyes.
Cytoskeleton
generally consists of proteins (see microtubules and microfilaments below) that provide a dynamic structural framework for the cell and can effect cell shape, locomotion, intracellular transport, and gene expression.
Endoplasmic membrane
he endoplasmic reticulum (ER) is defined as rough (RER)
or smooth (SER) ER. The RER contains ribosomes which serve as the location for protein synthesis (translation); whereas, the SER has an important role in steroidogenesis. In general, the ER is involved in the segregation, storage, and transport of various cellular
products (i.e. proteins, calcium).
Extracellular matrix
Consists of an intricate meshwork of proteins and polysaccharide molecules that is located in the extracellular space. The extracellular matrix is dynamic and provides structural support as well as being reservoir for a number of biologically important molecules.
Genome
Total amount of genetic information in a complete set of chromosomes
Golgi apparatus
This cellular organelle has an important role in the packaging and secretion of proteins.
Lysosomes
These organelles serve as an intracellular digestive system that breaks down products that may originate inside or outside the cell
Mitochondria
Serve as the source of energy (ATP) production for the cell. The mitochondria also contain a small amount of extra-genomic DNA (maternally contributed).
Microtubules and microfilaments
These structures are components of the cytoskeleton which provide structural support for a cell. The cytoskeleton is connected to the nuclear matrix (located in the nucleus) and the extracellular matrix (located outside the cell). Consequently, changes in the extracellular matrix can cause changes in the cytoskeleton and nuclear matrix which can cause changes in gene expression.
Nucleus
Contains chromosomes and is the site of almost all DNA replication and RNA synthesis. Following transcription (mRNA synthesis) mRNA is transported out of the nucleus and translated by ribosomes.
Nucleolus
Is a sub organelle located in the nucleus and is involved in the production and assembly of the components of ribosomes.
Alveolus
An oval sac lined with epithelial cells and having a lumen (e.g. mammary gland; an air sac in the lungs)
Cilium
Minute, hairlike process attached to the luminal surface of certain cells.
Duct
A tube or canal that carries fluid or secretions from a gland.
Epithelium
The tissue covering the external and internal surfaces of the body, including the linings of vessels and cavities. The description of an epithelium is based on
the number of cell layers (simple or stratified) and the shape of the cells (squamous, cuboidal, or columnar)
Lumen
Hollow center of a tubular organ
Mucosa
Includes an epithelial lining, the underlying connective tissue and underlying glands if present
Muscularis
Layers of smooth muscle which normally consist of an inner circular layer and an outer longitudinal layer.
Serosa
Outside covering of a connective tissue. Present on organs that are within a body cavity (e.g. the abdominal cavity).
Simple
Refers to a single layer of epithelial cells
Squamous
Plate-like cells that resemble scales.
Stratified
Refers to more than one layer of epithelial cells.
5’ Cap
methylated guanine residue added to the 5’ (beginning) end of the mature mRNA transcript during mRNA processing. The 5’ Cap is important for export of the transcript from the nucleus, increasing the half life of the transcript, and in promoting translation.
Exon
Protein coding region of a gene, represented in the mature mRNA transcript
HRE (Hormone Response Element)
A DNA sequence that binds to a hormone-stimulated transcription factor to alter the rate of transcription of a proximal gene; specific examples are: ERE (estrogen response element), PRE (progesterone response element), and GRE (glucocorticoid response element).
Intron
The portion of a gene that is transcribed to form the primary mRNA transcript (pre-mRNA), but is removed by splicing during processing into the mature mRNA transcript; does not encode the protein.
Promoter
DNA sequence to which the transcription apparatus (RNA pol) binds to initiate transcription
Polyadenylation
Addition of a poly(A) tail (a string of adenine residues) to the 3’ end of mature mRNA during processing. The poly(A) tail has the following functions: aids in the termination of translation, affects the stability of the mature mRNA transcript, assists with export of the mature transcript from the nucleus, and is important for translation
RE (Regulatory Element)
Generic term for a DNA sequence that serves as a binding site for a transcription factor and has a role in regulating the rate of transcription of a proximal gene.
RNA Polymerase (RNA pol)
An enzyme that transcribes pre-mRNA from a DNA
template; is recruited (or blocked) by transcription factors to the promoter.
Transcription
Transfer of information from a segment of double stranded DNA (gene) to a single strand of messenger RNA.
Transcription Factor (TF)
A protein that can regulate the rate of transcription of a gene by interacting with a DNA sequence that may or may not be near the gene.
Translation (protein synthesis)
Translation of the nucleotide sequence of a messenger
RNA molecule to the amino acid sequence of a protein
UTR (Untranslated region)
The region of mRNA still present in mature mRNA that is not translated into protein (upstream of the start codon = 5’ UTR, downstream of the stop codon = 3’ UTR).
