D-E Flashcards
Dendrites
A short branched extension of a nerve cell, along which impulses received from other cells at synapses are transmitted to the cell body
Desmosomes
A type of junctional complex, randomly arranged on the lateral sides of plasma membranes. They allow epithelial cells to resist shearing forces and are found in simple and stratified squamous epithelium
Provides adhesion between cells. There is an intracellular component.
Diastole
The portion of the cardiac cycle when the heart refills with blood following contraction. Ventricular diastole is when the ventricles are filling and relaxing, while atrial diastole when the atria are relaxing
Diffusion
The passive net movement of material from an area of high concentration to an area with lower concentration
Divergent evolution
The accumulation of differences between groups which can lead to the formation of new species
DNA helicase
An enzyme that moves directionally along a nucleic acid phosphodiester backbone, separating two annealed nucleic acid strands (DNA, RNA)
DNA ligase
An enzyme, that facilitates the joining of DNA strands together by catalyzing the formation of phosphodiester bond
DNA polymerase
An enzyme that creates DNA molecules by assembling nucleotides. These enzymes are essential to DNA replication and usually work in pairs to create two identical DNA strands from one original DNA molecule
Ectoderm
One of the primary germ layers in the very early embryo.
- nervous system
- skin
- cornea and lens of eyes
Endocrine glands
Any gland that secretes its products or hormones directly into the blood rather than through a duct
Endoderm
One of the primary germ layers
- Epithelial lining digestive tract
- Epithelial lining respiratory system
- Lining of urinary tract and reproductive system
- Liver
- Pancreas
- Thymus
- Thyroid and parathyroid
Endoplasmic reticulum
A network of tubules and flattened sacs that serve a variety of functions in the cell. The rough endoplasmic reticulum manufactures membranes and secretory proteins.
Smooth ER performs carbohydrates and lipid synthesis while also acting as a transitional area for vesicles that transport ER products to various destinations
Endopores
A dormant, tough, and non-reproductive structure produced by certain bacteria. It allows the bacterium to produce a dormant and highly resistant cell to preserve the cell’s genetic material in times of extreme stress
Enzyme
A biomolecule, usually a protein, that acts as a catalyst for biological reactions
Erythrocyte (RBC)
An anucleated cell that contains hemoglobin in order to transport oxygen throughout the body
Estrogen
A steroid hormone important to the maintenance of female secondary sex characteristics
Euchromatin
A loosely packed form of DNA . Euchromatin is prevalent in cells that are active in the transcription of many of their genes
Eukaryote
Any organism whose cells contain a nucleus and other organelles enclosed within membranes
Exocrine glands
Any gland that secretes its product by way of a duct to some environment external to the gland itself
Exocytosis
The process in which an intracellular vesicle moves to the plasma membrane and subsequent fusion of the vesicular membrane and plasma membrane ensues. The goal is to transport molecules outside of the cell
Exons
Any nucleotide sequence encoded by a gene that remains present within the final mature RNA product of the gene after introns have been removed by RNA splicing
Extracellular matrix (ECM)
A collection of extracellular molecules secreted by cells that provides structural and biochemical support to the surrounding cells
