Generalized Eukaryotic Workshop Flashcards
Cell Theory
- all living things are made up of cells
- cells are basic units of life.
- cells come only from other cells
- cells carry genetic information in the form of DNA. This genetic material is passed from parent to daughter cell.
What is light microscopy?
light is focused on a specimen by a glass lens.
The image is then magnified for projection on the eye or photographic film.
Used to study live cells, use of certain dyes or preparations may kill live specimens.
What is electron microscopy?
a beam of electrons is used instead of light and electromagnets are used instead of glass lenses.
Preparation of the specimen kkills cells, so it can not be used to study living cells.
What is cell fractionation?
Cells whose cell membranes have been ruptured are centrifuged at various speeds for varying lenghts of time to separate diff sizes, densities and shapes.
What is freeze fracture?
technique used to study cell membranes and organelles.
A frozen specimen is fractures with a cold knife, producing a fracture plane that generally splits lipid bilayer membranes.
Describe the nucleus
Its where the genetic material is contained.
The nuclear envelope, separates the nucleus from the rest of the cell, consist of two cell membranes and is perforated by nuclear pores. The nuclear pores regulate the passage of large macro molecules into and out of the nucleus.
Describe the nucleolus
Dense structure within the nucleus, is the site of ribosomal RNA (rRNA synthesis. The nucleus is not surrounded by a membrane. After assembly, the ribosomal subunits are exported from the nucleus to the cytoplasm, where they will participate in protein synthesis.
Describe the mitochondria
site of aerobic respiration and ATP production within the cell. “The power house”. Bound by an outer and inner phospholipid bilayer membrane. Outer membrane has pores which selectively allow molecules to enter the cell depending their size. Th space between the inner and outer membrane is known as the intermembrane space. The inner membrane has many convolutions called cristae and also houses the proteins of the electron transport chain. The area bound by the inner membrane is known as the mitochondrial matrix.
What is the endosymbiotic hypothesis
Mitochondria developed from early prok cells that began symbiotic relationship with ancestor euk. The mitochondria provided energy and the host of the cell providing nutrients and protection for the exterior environment.
Describe ribosomes
synthesized in the nucleus and exported into the cytoplasm.
responsible for protein synthesis.
Each consist of a large and small subunit which consist of rRNA and proteins.
Proteins designed for the cytoplasm are synthesized by free ribosomes.
Proteins designed for insertion or secretion are synthesized by ribosomes bound to the ER.
Describe the Endoplasmic Reticulum
extensive network of membrane enclosed spaces in the cytoplasm. The interior is called the lumen.
Describe Smooth ER
has no ribosomes on outer surface. Involved in lipid synthesis and detoxification of drugs and poisons.
Describe rough ER
has ribosomes on outer surface. Involved in protein synthesis
Describe Golgi Aparatus
Proteins are modified and sorted based on the destination.
Modification to the proteins include the addition to sugar groups to proteins process called glycosylation.
Describe lysosomes
Contain hydrolytic enzymes involved in intracellular digestion. These enzymes break down protein, carbohydrates and nucleic acids. pH=5.
what are peroxisomes
contain oxidative enzymes that catalyze rxns which hydrogen peroxide is produced and degraded. Break down fats into small molecules. used in the liver to detoxify potentially harmful compounds.
what is a cytoskeleton
network of specialized proteins that provide a framework for the cells shape. Also, involved in movement of organelles within a cell.
What are the three types of protein filaments that make up a cytoskeleton
Microfilaments
Intermediate Filaments
Microtubules
What are microfilaments
consist of two tangled stripes of actin (globular protein). involved in muscle contraction, along with thicker filaments of myosin.
What are intermediate filaments
fibrous protein coiled into thicker cables. Function in the structural support of a cell.
What are microtubules
hollow rods composed of two types of a globular protein called tubulin. Involved in the movement of organelles and chromosomes, maintenance of cell shape and motility.
what are centrioles
ONLY found in animal cells. are microtubule organizing centers (MTOCs) that anchor microtubules during mitosis.
whats cilia
small structures that move in a whip like fashion with the purpose of moving fluids along a cell surface or propelling a cell within a fluid.
Cilia lined the respiratory tract to move mucus, dead cells, dust and other matter to the mouth for expulsion.
what is a flagella
moves in a wave like fashion. used for motility.
In animal cells what are the three type of intracellular junctions?
tight, anchoring and gap junctions.
Describe tight junctions
the membranes of neighboring cells are attached , the cells are attached so tightly that no material can pass between cells or travel passed the junction. total barrier to transport and diffusion.
Describe anchoring junctions
found in cells subject to mechanical stress.
Describe gap junction
provide direct connection between the cytoplasm of one cell and the cytoplasm of neighboring cell via channels.
These channels are formed by proteins called connexins.
